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module altera_avalon_sc_fifo
#(
// --------------------------------------------------
// Parameters
// --------------------------------------------------
parameter SYMBOLS_PER_BEAT = 1,
parameter BITS_PER_SYMBOL = 8,
parameter FIFO_DEPTH = 16,
parameter CHANNEL_WIDTH = 0,
parameter ERROR_WIDTH = 0,
parameter USE_PACKETS = 0,
parameter USE_FILL_LEVEL = 0,
parameter USE_STORE_FORWARD = 0,
parameter USE_ALMOST_FULL_IF = 0,
parameter USE_ALMOST_EMPTY_IF = 0,
// --------------------------------------------------
// Empty latency is defined as the number of cycles
// required for a write to deassert the empty flag.
// For example, a latency of 1 means that the empty
// flag is deasserted on the cycle after a write.
//
// Another way to think of it is the latency for a
// write to propagate to the output.
//
// An empty latency of 0 implies lookahead, which is
// only implemented for the register-based FIFO.
// --------------------------------------------------
parameter EMPTY_LATENCY = 3,
parameter USE_MEMORY_BLOCKS = 1,
// --------------------------------------------------
// Internal Parameters
// --------------------------------------------------
parameter DATA_WIDTH = SYMBOLS_PER_BEAT * BITS_PER_SYMBOL,
parameter EMPTY_WIDTH = log2ceil(SYMBOLS_PER_BEAT)
)
(
// --------------------------------------------------
// Ports
// --------------------------------------------------
input clk,
input reset,
input [DATA_WIDTH-1: 0] in_data,
input in_valid,
input in_startofpacket,
input in_endofpacket,
input [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] in_empty,
input [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] in_error,
input [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] in_channel,
output in_ready,
output [DATA_WIDTH-1 : 0] out_data,
output reg out_valid,
output out_startofpacket,
output out_endofpacket,
output [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] out_empty,
output [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] out_error,
output [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] out_channel,
input out_ready,
input [(USE_STORE_FORWARD ? 2 : 1) : 0] csr_address,
input csr_write,
input csr_read,
input [31 : 0] csr_writedata,
output reg [31 : 0] csr_readdata,
output wire almost_full_data,
output wire almost_empty_data
);
// --------------------------------------------------
// Local Parameters
// --------------------------------------------------
localparam ADDR_WIDTH = log2ceil(FIFO_DEPTH);
localparam DEPTH = FIFO_DEPTH;
localparam PKT_SIGNALS_WIDTH = 2 + EMPTY_WIDTH;
localparam PAYLOAD_WIDTH = (USE_PACKETS == 1) ?
2 + EMPTY_WIDTH + DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH:
DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH;
// --------------------------------------------------
// Internal Signals
// --------------------------------------------------
genvar i;
reg [PAYLOAD_WIDTH-1 : 0] mem [DEPTH-1 : 0];
reg [ADDR_WIDTH-1 : 0] wr_ptr;
reg [ADDR_WIDTH-1 : 0] rd_ptr;
reg [DEPTH-1 : 0] mem_used;
wire [ADDR_WIDTH-1 : 0] next_wr_ptr;
wire [ADDR_WIDTH-1 : 0] next_rd_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_wr_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_rd_ptr;
wire [ADDR_WIDTH-1 : 0] mem_rd_ptr;
wire read;
wire write;
reg empty;
reg next_empty;
reg full;
reg next_full;
wire [PKT_SIGNALS_WIDTH-1 : 0] in_packet_signals;
wire [PKT_SIGNALS_WIDTH-1 : 0] out_packet_signals;
wire [PAYLOAD_WIDTH-1 : 0] in_payload;
reg [PAYLOAD_WIDTH-1 : 0] internal_out_payload;
reg [PAYLOAD_WIDTH-1 : 0] out_payload;
reg internal_out_valid;
wire internal_out_ready;
reg [ADDR_WIDTH : 0] fifo_fill_level;
reg [ADDR_WIDTH : 0] fill_level;
reg [ADDR_WIDTH-1 : 0] sop_ptr = 0;
wire [ADDR_WIDTH-1 : 0] curr_sop_ptr;
reg [23:0] almost_full_threshold;
reg [23:0] almost_empty_threshold;
reg [23:0] cut_through_threshold;
reg [15:0] pkt_cnt;
reg drop_on_error_en;
reg error_in_pkt;
reg pkt_has_started;
reg sop_has_left_fifo;
reg fifo_too_small_r;
reg pkt_cnt_eq_zero;
reg pkt_cnt_eq_one;
wire wait_for_threshold;
reg pkt_mode;
wire wait_for_pkt;
wire ok_to_forward;
wire in_pkt_eop_arrive;
wire out_pkt_leave;
wire in_pkt_start;
wire in_pkt_error;
wire drop_on_error;
wire fifo_too_small;
wire out_pkt_sop_leave;
wire [31:0] max_fifo_size;
reg fifo_fill_level_lt_cut_through_threshold;
// --------------------------------------------------
// Define Payload
//
// Icky part where we decide which signals form the
// payload to the FIFO with generate blocks.
// --------------------------------------------------
generate
if (EMPTY_WIDTH > 0) begin : gen_blk1
assign in_packet_signals = {in_startofpacket, in_endofpacket, in_empty};
assign {out_startofpacket, out_endofpacket, out_empty} = out_packet_signals;
end
else begin : gen_blk1_else
assign out_empty = in_error;
assign in_packet_signals = {in_startofpacket, in_endofpacket};
assign {out_startofpacket, out_endofpacket} = out_packet_signals;
end
endgenerate
generate
if (USE_PACKETS) begin : gen_blk2
if (ERROR_WIDTH > 0) begin : gen_blk3
if (CHANNEL_WIDTH > 0) begin : gen_blk4
assign in_payload = {in_packet_signals, in_data, in_error, in_channel};
assign {out_packet_signals, out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk4_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data, in_error};
assign {out_packet_signals, out_data, out_error} = out_payload;
end
end
else begin : gen_blk3_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk5
assign in_payload = {in_packet_signals, in_data, in_channel};
assign {out_packet_signals, out_data, out_channel} = out_payload;
end
else begin : gen_blk5_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data};
assign {out_packet_signals, out_data} = out_payload;
end
end
end
else begin : gen_blk2_else
assign out_packet_signals = 0;
if (ERROR_WIDTH > 0) begin : gen_blk6
if (CHANNEL_WIDTH > 0) begin : gen_blk7
assign in_payload = {in_data, in_error, in_channel};
assign {out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk7_else
assign out_channel = in_channel;
assign in_payload = {in_data, in_error};
assign {out_data, out_error} = out_payload;
end
end
else begin : gen_blk6_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk8
assign in_payload = {in_data, in_channel};
assign {out_data, out_channel} = out_payload;
end
else begin : gen_blk8_else
assign out_channel = in_channel;
assign in_payload = in_data;
assign out_data = out_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Memory-based FIFO storage
//
// To allow a ready latency of 0, the read index is
// obtained from the next read pointer and memory
// outputs are unregistered.
//
// If the empty latency is 1, we infer bypass logic
// around the memory so writes propagate to the
// outputs on the next cycle.
//
// Do not change the way this is coded: Quartus needs
// a perfect match to the template, and any attempt to
// refactor the two always blocks into one will break
// memory inference.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk9
if (EMPTY_LATENCY == 1) begin : gen_blk10
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] = in_payload;
internal_out_payload = mem[mem_rd_ptr];
end
end else begin : gen_blk10_else
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] <= in_payload;
internal_out_payload <= mem[mem_rd_ptr];
end
end
assign mem_rd_ptr = next_rd_ptr;
end else begin : gen_blk9_else
// --------------------------------------------------
// Register-based FIFO storage
//
// Uses a shift register as the storage element. Each
// shift register slot has a bit which indicates if
// the slot is occupied (credit to Sam H for the idea).
// The occupancy bits are contiguous and start from the
// lsb, so 0000, 0001, 0011, 0111, 1111 for a 4-deep
// FIFO.
//
// Each slot is enabled during a read or when it
// is unoccupied. New data is always written to every
// going-to-be-empty slot (we keep track of which ones
// are actually useful with the occupancy bits). On a
// read we shift occupied slots.
//
// The exception is the last slot, which always gets
// new data when it is unoccupied.
// --------------------------------------------------
for (i = 0; i < DEPTH-1; i = i + 1) begin : shift_reg
always @(posedge clk or posedge reset) begin
if (reset) begin
mem[i] <= 0;
end
else if (read || !mem_used[i]) begin
if (!mem_used[i+1])
mem[i] <= in_payload;
else
mem[i] <= mem[i+1];
end
end
end
always @(posedge clk, posedge reset) begin
if (reset) begin
mem[DEPTH-1] <= 0;
end
else begin
if (DEPTH == 1) begin
if (write)
mem[DEPTH-1] <= in_payload;
end
else if (!mem_used[DEPTH-1])
mem[DEPTH-1] <= in_payload;
end
end
end
endgenerate
assign read = internal_out_ready && internal_out_valid && ok_to_forward;
assign write = in_ready && in_valid;
// --------------------------------------------------
// Pointer Management
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk11
assign incremented_wr_ptr = wr_ptr + 1'b1;
assign incremented_rd_ptr = rd_ptr + 1'b1;
assign next_wr_ptr = drop_on_error ? curr_sop_ptr : write ? incremented_wr_ptr : wr_ptr;
assign next_rd_ptr = (read) ? incremented_rd_ptr : rd_ptr;
always @(posedge clk or posedge reset) begin
if (reset) begin
wr_ptr <= 0;
rd_ptr <= 0;
end
else begin
wr_ptr <= next_wr_ptr;
rd_ptr <= next_rd_ptr;
end
end
end else begin : gen_blk11_else
// --------------------------------------------------
// Shift Register Occupancy Bits
//
// Consider a 4-deep FIFO with 2 entries: 0011
// On a read and write, do not modify the bits.
// On a write, left-shift the bits to get 0111.
// On a read, right-shift the bits to get 0001.
//
// Also, on a write we set bit0 (the head), while
// clearing the tail on a read.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[0] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[0] <= 1;
else if (read) begin
if (DEPTH > 1)
mem_used[0] <= mem_used[1];
else
mem_used[0] <= 0;
end
end
end
end
if (DEPTH > 1) begin : gen_blk12
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[DEPTH-1] <= 0;
end
else begin
if (write ^ read) begin
mem_used[DEPTH-1] <= 0;
if (write)
mem_used[DEPTH-1] <= mem_used[DEPTH-2];
end
end
end
end
for (i = 1; i < DEPTH-1; i = i + 1) begin : storage_logic
always @(posedge clk, posedge reset) begin
if (reset) begin
mem_used[i] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[i] <= mem_used[i-1];
else if (read)
mem_used[i] <= mem_used[i+1];
end
end
end
end
end
endgenerate
// --------------------------------------------------
// Memory FIFO Status Management
//
// Generates the full and empty signals from the
// pointers. The FIFO is full when the next write
// pointer will be equal to the read pointer after
// a write. Reading from a FIFO clears full.
//
// The FIFO is empty when the next read pointer will
// be equal to the write pointer after a read. Writing
// to a FIFO clears empty.
//
// A simultaneous read and write must not change any of
// the empty or full flags unless there is a drop on error event.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk13
always @* begin
next_full = full;
next_empty = empty;
if (read && !write) begin
next_full = 1'b0;
if (incremented_rd_ptr == wr_ptr)
next_empty = 1'b1;
end
if (write && !read) begin
if (!drop_on_error)
next_empty = 1'b0;
else if (curr_sop_ptr == rd_ptr) // drop on error and only 1 pkt in fifo
next_empty = 1'b1;
if (incremented_wr_ptr == rd_ptr && !drop_on_error)
next_full = 1'b1;
end
if (write && read && drop_on_error) begin
if (curr_sop_ptr == next_rd_ptr)
next_empty = 1'b1;
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
empty <= 1;
full <= 0;
end
else begin
empty <= next_empty;
full <= next_full;
end
end
end else begin : gen_blk13_else
// --------------------------------------------------
// Register FIFO Status Management
//
// Full when the tail occupancy bit is 1. Empty when
// the head occupancy bit is 0.
// --------------------------------------------------
always @* begin
full = mem_used[DEPTH-1];
empty = !mem_used[0];
// ------------------------------------------
// For a single slot FIFO, reading clears the
// full status immediately.
// ------------------------------------------
if (DEPTH == 1)
full = mem_used[0] && !read;
internal_out_payload = mem[0];
// ------------------------------------------
// Writes clear empty immediately for lookahead modes.
// Note that we use in_valid instead of write to avoid
// combinational loops (in lookahead mode, qualifying
// with in_ready is meaningless).
//
// In a 1-deep FIFO, a possible combinational loop runs
// from write -> out_valid -> out_ready -> write
// ------------------------------------------
if (EMPTY_LATENCY == 0) begin
empty = !mem_used[0] && !in_valid;
if (!mem_used[0] && in_valid)
internal_out_payload = in_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Avalon-ST Signals
//
// The in_ready signal is straightforward.
//
// To match memory latency when empty latency > 1,
// out_valid assertions must be delayed by one clock
// cycle.
//
// Note: out_valid deassertions must not be delayed or
// the FIFO will underflow.
// --------------------------------------------------
assign in_ready = !full;
assign internal_out_ready = out_ready || !out_valid;
generate if (EMPTY_LATENCY > 1) begin : gen_blk14
always @(posedge clk or posedge reset) begin
if (reset)
internal_out_valid <= 0;
else begin
internal_out_valid <= !empty & ok_to_forward & ~drop_on_error;
if (read) begin
if (incremented_rd_ptr == wr_ptr)
internal_out_valid <= 1'b0;
end
end
end
end else begin : gen_blk14_else
always @* begin
internal_out_valid = !empty & ok_to_forward;
end
end
endgenerate
// --------------------------------------------------
// Single Output Pipeline Stage
//
// This output pipeline stage is enabled if the FIFO's
// empty latency is set to 3 (default). It is disabled
// for all other allowed latencies.
//
// Reason: The memory outputs are unregistered, so we have to
// register the output or fmax will drop if combinatorial
// logic is present on the output datapath.
//
// Q: The Avalon-ST spec says that I have to register my outputs
// But isn't the memory counted as a register?
// A: The path from the address lookup to the memory output is
// slow. Registering the memory outputs is a good idea.
//
// The registers get packed into the memory by the fitter
// which means minimal resources are consumed (the result
// is a altsyncram with registered outputs, available on
// all modern Altera devices).
//
// This output stage acts as an extra slot in the FIFO,
// and complicates the fill level.
// --------------------------------------------------
generate if (EMPTY_LATENCY == 3) begin : gen_blk15
always @(posedge clk or posedge reset) begin
if (reset) begin
out_valid <= 0;
out_payload <= 0;
end
else begin
if (internal_out_ready) begin
out_valid <= internal_out_valid & ok_to_forward;
out_payload <= internal_out_payload;
end
end
end
end
else begin : gen_blk15_else
always @* begin
out_valid = internal_out_valid;
out_payload = internal_out_payload;
end
end
endgenerate
// --------------------------------------------------
// Fill Level
//
// The fill level is calculated from the next write
// and read pointers to avoid unnecessary latency
// and logic.
//
// However, if the store-and-forward mode of the FIFO
// is enabled, the fill level is an up-down counter
// for fmax optimization reasons.
//
// If the output pipeline is enabled, the fill level
// must account for it, or we'll always be off by one.
// This may, or may not be important depending on the
// application.
//
// For now, we'll always calculate the exact fill level
// at the cost of an extra adder when the output stage
// is enabled.
// --------------------------------------------------
generate if (USE_FILL_LEVEL) begin : gen_blk16
wire [31:0] depth32;
assign depth32 = DEPTH;
if (USE_STORE_FORWARD) begin
reg [ADDR_WIDTH : 0] curr_packet_len_less_one;
// --------------------------------------------------
// We only drop on endofpacket. As long as we don't add to the fill
// level on the dropped endofpacket cycle, we can simply subtract
// (packet length - 1) from the fill level for dropped packets.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
curr_packet_len_less_one <= 0;
end else begin
if (write) begin
curr_packet_len_less_one <= curr_packet_len_less_one + 1'b1;
if (in_endofpacket)
curr_packet_len_less_one <= 0;
end
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
fifo_fill_level <= 0;
end else if (drop_on_error) begin
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one;
if (read)
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one - 1'b1;
end else if (write && !read) begin
fifo_fill_level <= fifo_fill_level + 1'b1;
end else if (read && !write) begin
fifo_fill_level <= fifo_fill_level - 1'b1;
end
end
end else begin
always @(posedge clk or posedge reset) begin
if (reset)
fifo_fill_level <= 0;
else if (next_full & !drop_on_error)
fifo_fill_level <= depth32[ADDR_WIDTH:0];
else begin
fifo_fill_level[ADDR_WIDTH] <= 1'b0;
fifo_fill_level[ADDR_WIDTH-1 : 0] <= next_wr_ptr - next_rd_ptr;
end
end
end
always @* begin
fill_level = fifo_fill_level;
if (EMPTY_LATENCY == 3)
fill_level = fifo_fill_level + {{ADDR_WIDTH{1'b0}}, out_valid};
end
end
else begin : gen_blk16_else
always @* begin
fill_level = 0;
end
end
endgenerate
generate if (USE_ALMOST_FULL_IF) begin : gen_blk17
assign almost_full_data = (fill_level >= almost_full_threshold);
end
else
assign almost_full_data = 0;
endgenerate
generate if (USE_ALMOST_EMPTY_IF) begin : gen_blk18
assign almost_empty_data = (fill_level <= almost_empty_threshold);
end
else
assign almost_empty_data = 0;
endgenerate
// --------------------------------------------------
// Avalon-MM Status & Control Connection Point
//
// Register map:
//
// | Addr | RW | 31 - 0 |
// | 0 | R | Fill level |
//
// The registering of this connection point means
// that there is a cycle of latency between
// reads/writes and the updating of the fill level.
// --------------------------------------------------
generate if (USE_STORE_FORWARD) begin : gen_blk19
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
cut_through_threshold <= 0;
drop_on_error_en <= 0;
csr_readdata <= 0;
pkt_mode <= 1'b1;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 5)
csr_readdata <= {31'b0, drop_on_error_en};
else if (csr_address == 4)
csr_readdata <= {8'b0, cut_through_threshold};
else if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b101)
drop_on_error_en <= csr_writedata[0];
else if(csr_address == 3'b100) begin
cut_through_threshold <= csr_writedata[23:0];
pkt_mode <= (csr_writedata[23:0] == 0);
end
else if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else if (USE_ALMOST_FULL_IF || USE_ALMOST_EMPTY_IF) begin : gen_blk19_else1
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
csr_readdata <= 0;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else begin : gen_blk19_else2
always @(posedge clk or posedge reset) begin
if (reset) begin
csr_readdata <= 0;
end
else if (csr_read) begin
csr_readdata <= 0;
if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
end
end
endgenerate
// --------------------------------------------------
// Store and forward logic
// --------------------------------------------------
// if the fifo gets full before the entire packet or the
// cut-threshold condition is met then start sending out
// data in order to avoid dead-lock situation
generate if (USE_STORE_FORWARD) begin : gen_blk20
assign wait_for_threshold = (fifo_fill_level_lt_cut_through_threshold) & wait_for_pkt ;
assign wait_for_pkt = pkt_cnt_eq_zero | (pkt_cnt_eq_one & out_pkt_leave);
assign ok_to_forward = (pkt_mode ? (~wait_for_pkt | ~pkt_has_started) :
~wait_for_threshold) | fifo_too_small_r;
assign in_pkt_eop_arrive = in_valid & in_ready & in_endofpacket;
assign in_pkt_start = in_valid & in_ready & in_startofpacket;
assign in_pkt_error = in_valid & in_ready & |in_error;
assign out_pkt_sop_leave = out_valid & out_ready & out_startofpacket;
assign out_pkt_leave = out_valid & out_ready & out_endofpacket;
assign fifo_too_small = (pkt_mode ? wait_for_pkt : wait_for_threshold) & full & out_ready;
// count packets coming and going into the fifo
always @(posedge clk or posedge reset) begin
if (reset) begin
pkt_cnt <= 0;
pkt_has_started <= 0;
sop_has_left_fifo <= 0;
fifo_too_small_r <= 0;
pkt_cnt_eq_zero <= 1'b1;
pkt_cnt_eq_one <= 1'b0;
fifo_fill_level_lt_cut_through_threshold <= 1'b1;
end
else begin
fifo_fill_level_lt_cut_through_threshold <= fifo_fill_level < cut_through_threshold;
fifo_too_small_r <= fifo_too_small;
if( in_pkt_eop_arrive )
sop_has_left_fifo <= 1'b0;
else if (out_pkt_sop_leave & pkt_cnt_eq_zero )
sop_has_left_fifo <= 1'b1;
if (in_pkt_eop_arrive & ~out_pkt_leave & ~drop_on_error ) begin
pkt_cnt <= pkt_cnt + 1'b1;
pkt_cnt_eq_zero <= 0;
if (pkt_cnt == 0)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
else if((~in_pkt_eop_arrive | drop_on_error) & out_pkt_leave) begin
pkt_cnt <= pkt_cnt - 1'b1;
if (pkt_cnt == 1)
pkt_cnt_eq_zero <= 1'b1;
else
pkt_cnt_eq_zero <= 1'b0;
if (pkt_cnt == 2)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
if (in_pkt_start)
pkt_has_started <= 1'b1;
else if (in_pkt_eop_arrive)
pkt_has_started <= 1'b0;
end
end
// drop on error logic
always @(posedge clk or posedge reset) begin
if (reset) begin
sop_ptr <= 0;
error_in_pkt <= 0;
end
else begin
// save the location of the SOP
if ( in_pkt_start )
sop_ptr <= wr_ptr;
// remember if error in pkt
// log error only if packet has already started
if (in_pkt_eop_arrive)
error_in_pkt <= 1'b0;
else if ( in_pkt_error & (pkt_has_started | in_pkt_start))
error_in_pkt <= 1'b1;
end
end
assign drop_on_error = drop_on_error_en & (error_in_pkt | in_pkt_error) & in_pkt_eop_arrive &
~sop_has_left_fifo & ~(out_pkt_sop_leave & pkt_cnt_eq_zero);
assign curr_sop_ptr = (write && in_startofpacket && in_endofpacket) ? wr_ptr : sop_ptr;
end
else begin : gen_blk20_else
assign ok_to_forward = 1'b1;
assign drop_on_error = 1'b0;
if (ADDR_WIDTH <= 1)
assign curr_sop_ptr = 1'b0;
else
assign curr_sop_ptr = {ADDR_WIDTH - 1 { 1'b0 }};
end
endgenerate
// --------------------------------------------------
// Calculates the log2ceil of the input value
// --------------------------------------------------
function integer log2ceil;
input integer val;
reg[31:0] i;
begin
i = 1;
log2ceil = 0;
while (i < val) begin
log2ceil = log2ceil + 1;
i = i[30:0] << 1;
end
end
endfunction
endmodule |
module altera_avalon_sc_fifo
#(
// --------------------------------------------------
// Parameters
// --------------------------------------------------
parameter SYMBOLS_PER_BEAT = 1,
parameter BITS_PER_SYMBOL = 8,
parameter FIFO_DEPTH = 16,
parameter CHANNEL_WIDTH = 0,
parameter ERROR_WIDTH = 0,
parameter USE_PACKETS = 0,
parameter USE_FILL_LEVEL = 0,
parameter USE_STORE_FORWARD = 0,
parameter USE_ALMOST_FULL_IF = 0,
parameter USE_ALMOST_EMPTY_IF = 0,
// --------------------------------------------------
// Empty latency is defined as the number of cycles
// required for a write to deassert the empty flag.
// For example, a latency of 1 means that the empty
// flag is deasserted on the cycle after a write.
//
// Another way to think of it is the latency for a
// write to propagate to the output.
//
// An empty latency of 0 implies lookahead, which is
// only implemented for the register-based FIFO.
// --------------------------------------------------
parameter EMPTY_LATENCY = 3,
parameter USE_MEMORY_BLOCKS = 1,
// --------------------------------------------------
// Internal Parameters
// --------------------------------------------------
parameter DATA_WIDTH = SYMBOLS_PER_BEAT * BITS_PER_SYMBOL,
parameter EMPTY_WIDTH = log2ceil(SYMBOLS_PER_BEAT)
)
(
// --------------------------------------------------
// Ports
// --------------------------------------------------
input clk,
input reset,
input [DATA_WIDTH-1: 0] in_data,
input in_valid,
input in_startofpacket,
input in_endofpacket,
input [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] in_empty,
input [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] in_error,
input [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] in_channel,
output in_ready,
output [DATA_WIDTH-1 : 0] out_data,
output reg out_valid,
output out_startofpacket,
output out_endofpacket,
output [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] out_empty,
output [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] out_error,
output [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] out_channel,
input out_ready,
input [(USE_STORE_FORWARD ? 2 : 1) : 0] csr_address,
input csr_write,
input csr_read,
input [31 : 0] csr_writedata,
output reg [31 : 0] csr_readdata,
output wire almost_full_data,
output wire almost_empty_data
);
// --------------------------------------------------
// Local Parameters
// --------------------------------------------------
localparam ADDR_WIDTH = log2ceil(FIFO_DEPTH);
localparam DEPTH = FIFO_DEPTH;
localparam PKT_SIGNALS_WIDTH = 2 + EMPTY_WIDTH;
localparam PAYLOAD_WIDTH = (USE_PACKETS == 1) ?
2 + EMPTY_WIDTH + DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH:
DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH;
// --------------------------------------------------
// Internal Signals
// --------------------------------------------------
genvar i;
reg [PAYLOAD_WIDTH-1 : 0] mem [DEPTH-1 : 0];
reg [ADDR_WIDTH-1 : 0] wr_ptr;
reg [ADDR_WIDTH-1 : 0] rd_ptr;
reg [DEPTH-1 : 0] mem_used;
wire [ADDR_WIDTH-1 : 0] next_wr_ptr;
wire [ADDR_WIDTH-1 : 0] next_rd_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_wr_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_rd_ptr;
wire [ADDR_WIDTH-1 : 0] mem_rd_ptr;
wire read;
wire write;
reg empty;
reg next_empty;
reg full;
reg next_full;
wire [PKT_SIGNALS_WIDTH-1 : 0] in_packet_signals;
wire [PKT_SIGNALS_WIDTH-1 : 0] out_packet_signals;
wire [PAYLOAD_WIDTH-1 : 0] in_payload;
reg [PAYLOAD_WIDTH-1 : 0] internal_out_payload;
reg [PAYLOAD_WIDTH-1 : 0] out_payload;
reg internal_out_valid;
wire internal_out_ready;
reg [ADDR_WIDTH : 0] fifo_fill_level;
reg [ADDR_WIDTH : 0] fill_level;
reg [ADDR_WIDTH-1 : 0] sop_ptr = 0;
wire [ADDR_WIDTH-1 : 0] curr_sop_ptr;
reg [23:0] almost_full_threshold;
reg [23:0] almost_empty_threshold;
reg [23:0] cut_through_threshold;
reg [15:0] pkt_cnt;
reg drop_on_error_en;
reg error_in_pkt;
reg pkt_has_started;
reg sop_has_left_fifo;
reg fifo_too_small_r;
reg pkt_cnt_eq_zero;
reg pkt_cnt_eq_one;
wire wait_for_threshold;
reg pkt_mode;
wire wait_for_pkt;
wire ok_to_forward;
wire in_pkt_eop_arrive;
wire out_pkt_leave;
wire in_pkt_start;
wire in_pkt_error;
wire drop_on_error;
wire fifo_too_small;
wire out_pkt_sop_leave;
wire [31:0] max_fifo_size;
reg fifo_fill_level_lt_cut_through_threshold;
// --------------------------------------------------
// Define Payload
//
// Icky part where we decide which signals form the
// payload to the FIFO with generate blocks.
// --------------------------------------------------
generate
if (EMPTY_WIDTH > 0) begin : gen_blk1
assign in_packet_signals = {in_startofpacket, in_endofpacket, in_empty};
assign {out_startofpacket, out_endofpacket, out_empty} = out_packet_signals;
end
else begin : gen_blk1_else
assign out_empty = in_error;
assign in_packet_signals = {in_startofpacket, in_endofpacket};
assign {out_startofpacket, out_endofpacket} = out_packet_signals;
end
endgenerate
generate
if (USE_PACKETS) begin : gen_blk2
if (ERROR_WIDTH > 0) begin : gen_blk3
if (CHANNEL_WIDTH > 0) begin : gen_blk4
assign in_payload = {in_packet_signals, in_data, in_error, in_channel};
assign {out_packet_signals, out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk4_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data, in_error};
assign {out_packet_signals, out_data, out_error} = out_payload;
end
end
else begin : gen_blk3_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk5
assign in_payload = {in_packet_signals, in_data, in_channel};
assign {out_packet_signals, out_data, out_channel} = out_payload;
end
else begin : gen_blk5_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data};
assign {out_packet_signals, out_data} = out_payload;
end
end
end
else begin : gen_blk2_else
assign out_packet_signals = 0;
if (ERROR_WIDTH > 0) begin : gen_blk6
if (CHANNEL_WIDTH > 0) begin : gen_blk7
assign in_payload = {in_data, in_error, in_channel};
assign {out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk7_else
assign out_channel = in_channel;
assign in_payload = {in_data, in_error};
assign {out_data, out_error} = out_payload;
end
end
else begin : gen_blk6_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk8
assign in_payload = {in_data, in_channel};
assign {out_data, out_channel} = out_payload;
end
else begin : gen_blk8_else
assign out_channel = in_channel;
assign in_payload = in_data;
assign out_data = out_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Memory-based FIFO storage
//
// To allow a ready latency of 0, the read index is
// obtained from the next read pointer and memory
// outputs are unregistered.
//
// If the empty latency is 1, we infer bypass logic
// around the memory so writes propagate to the
// outputs on the next cycle.
//
// Do not change the way this is coded: Quartus needs
// a perfect match to the template, and any attempt to
// refactor the two always blocks into one will break
// memory inference.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk9
if (EMPTY_LATENCY == 1) begin : gen_blk10
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] = in_payload;
internal_out_payload = mem[mem_rd_ptr];
end
end else begin : gen_blk10_else
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] <= in_payload;
internal_out_payload <= mem[mem_rd_ptr];
end
end
assign mem_rd_ptr = next_rd_ptr;
end else begin : gen_blk9_else
// --------------------------------------------------
// Register-based FIFO storage
//
// Uses a shift register as the storage element. Each
// shift register slot has a bit which indicates if
// the slot is occupied (credit to Sam H for the idea).
// The occupancy bits are contiguous and start from the
// lsb, so 0000, 0001, 0011, 0111, 1111 for a 4-deep
// FIFO.
//
// Each slot is enabled during a read or when it
// is unoccupied. New data is always written to every
// going-to-be-empty slot (we keep track of which ones
// are actually useful with the occupancy bits). On a
// read we shift occupied slots.
//
// The exception is the last slot, which always gets
// new data when it is unoccupied.
// --------------------------------------------------
for (i = 0; i < DEPTH-1; i = i + 1) begin : shift_reg
always @(posedge clk or posedge reset) begin
if (reset) begin
mem[i] <= 0;
end
else if (read || !mem_used[i]) begin
if (!mem_used[i+1])
mem[i] <= in_payload;
else
mem[i] <= mem[i+1];
end
end
end
always @(posedge clk, posedge reset) begin
if (reset) begin
mem[DEPTH-1] <= 0;
end
else begin
if (DEPTH == 1) begin
if (write)
mem[DEPTH-1] <= in_payload;
end
else if (!mem_used[DEPTH-1])
mem[DEPTH-1] <= in_payload;
end
end
end
endgenerate
assign read = internal_out_ready && internal_out_valid && ok_to_forward;
assign write = in_ready && in_valid;
// --------------------------------------------------
// Pointer Management
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk11
assign incremented_wr_ptr = wr_ptr + 1'b1;
assign incremented_rd_ptr = rd_ptr + 1'b1;
assign next_wr_ptr = drop_on_error ? curr_sop_ptr : write ? incremented_wr_ptr : wr_ptr;
assign next_rd_ptr = (read) ? incremented_rd_ptr : rd_ptr;
always @(posedge clk or posedge reset) begin
if (reset) begin
wr_ptr <= 0;
rd_ptr <= 0;
end
else begin
wr_ptr <= next_wr_ptr;
rd_ptr <= next_rd_ptr;
end
end
end else begin : gen_blk11_else
// --------------------------------------------------
// Shift Register Occupancy Bits
//
// Consider a 4-deep FIFO with 2 entries: 0011
// On a read and write, do not modify the bits.
// On a write, left-shift the bits to get 0111.
// On a read, right-shift the bits to get 0001.
//
// Also, on a write we set bit0 (the head), while
// clearing the tail on a read.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[0] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[0] <= 1;
else if (read) begin
if (DEPTH > 1)
mem_used[0] <= mem_used[1];
else
mem_used[0] <= 0;
end
end
end
end
if (DEPTH > 1) begin : gen_blk12
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[DEPTH-1] <= 0;
end
else begin
if (write ^ read) begin
mem_used[DEPTH-1] <= 0;
if (write)
mem_used[DEPTH-1] <= mem_used[DEPTH-2];
end
end
end
end
for (i = 1; i < DEPTH-1; i = i + 1) begin : storage_logic
always @(posedge clk, posedge reset) begin
if (reset) begin
mem_used[i] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[i] <= mem_used[i-1];
else if (read)
mem_used[i] <= mem_used[i+1];
end
end
end
end
end
endgenerate
// --------------------------------------------------
// Memory FIFO Status Management
//
// Generates the full and empty signals from the
// pointers. The FIFO is full when the next write
// pointer will be equal to the read pointer after
// a write. Reading from a FIFO clears full.
//
// The FIFO is empty when the next read pointer will
// be equal to the write pointer after a read. Writing
// to a FIFO clears empty.
//
// A simultaneous read and write must not change any of
// the empty or full flags unless there is a drop on error event.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk13
always @* begin
next_full = full;
next_empty = empty;
if (read && !write) begin
next_full = 1'b0;
if (incremented_rd_ptr == wr_ptr)
next_empty = 1'b1;
end
if (write && !read) begin
if (!drop_on_error)
next_empty = 1'b0;
else if (curr_sop_ptr == rd_ptr) // drop on error and only 1 pkt in fifo
next_empty = 1'b1;
if (incremented_wr_ptr == rd_ptr && !drop_on_error)
next_full = 1'b1;
end
if (write && read && drop_on_error) begin
if (curr_sop_ptr == next_rd_ptr)
next_empty = 1'b1;
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
empty <= 1;
full <= 0;
end
else begin
empty <= next_empty;
full <= next_full;
end
end
end else begin : gen_blk13_else
// --------------------------------------------------
// Register FIFO Status Management
//
// Full when the tail occupancy bit is 1. Empty when
// the head occupancy bit is 0.
// --------------------------------------------------
always @* begin
full = mem_used[DEPTH-1];
empty = !mem_used[0];
// ------------------------------------------
// For a single slot FIFO, reading clears the
// full status immediately.
// ------------------------------------------
if (DEPTH == 1)
full = mem_used[0] && !read;
internal_out_payload = mem[0];
// ------------------------------------------
// Writes clear empty immediately for lookahead modes.
// Note that we use in_valid instead of write to avoid
// combinational loops (in lookahead mode, qualifying
// with in_ready is meaningless).
//
// In a 1-deep FIFO, a possible combinational loop runs
// from write -> out_valid -> out_ready -> write
// ------------------------------------------
if (EMPTY_LATENCY == 0) begin
empty = !mem_used[0] && !in_valid;
if (!mem_used[0] && in_valid)
internal_out_payload = in_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Avalon-ST Signals
//
// The in_ready signal is straightforward.
//
// To match memory latency when empty latency > 1,
// out_valid assertions must be delayed by one clock
// cycle.
//
// Note: out_valid deassertions must not be delayed or
// the FIFO will underflow.
// --------------------------------------------------
assign in_ready = !full;
assign internal_out_ready = out_ready || !out_valid;
generate if (EMPTY_LATENCY > 1) begin : gen_blk14
always @(posedge clk or posedge reset) begin
if (reset)
internal_out_valid <= 0;
else begin
internal_out_valid <= !empty & ok_to_forward & ~drop_on_error;
if (read) begin
if (incremented_rd_ptr == wr_ptr)
internal_out_valid <= 1'b0;
end
end
end
end else begin : gen_blk14_else
always @* begin
internal_out_valid = !empty & ok_to_forward;
end
end
endgenerate
// --------------------------------------------------
// Single Output Pipeline Stage
//
// This output pipeline stage is enabled if the FIFO's
// empty latency is set to 3 (default). It is disabled
// for all other allowed latencies.
//
// Reason: The memory outputs are unregistered, so we have to
// register the output or fmax will drop if combinatorial
// logic is present on the output datapath.
//
// Q: The Avalon-ST spec says that I have to register my outputs
// But isn't the memory counted as a register?
// A: The path from the address lookup to the memory output is
// slow. Registering the memory outputs is a good idea.
//
// The registers get packed into the memory by the fitter
// which means minimal resources are consumed (the result
// is a altsyncram with registered outputs, available on
// all modern Altera devices).
//
// This output stage acts as an extra slot in the FIFO,
// and complicates the fill level.
// --------------------------------------------------
generate if (EMPTY_LATENCY == 3) begin : gen_blk15
always @(posedge clk or posedge reset) begin
if (reset) begin
out_valid <= 0;
out_payload <= 0;
end
else begin
if (internal_out_ready) begin
out_valid <= internal_out_valid & ok_to_forward;
out_payload <= internal_out_payload;
end
end
end
end
else begin : gen_blk15_else
always @* begin
out_valid = internal_out_valid;
out_payload = internal_out_payload;
end
end
endgenerate
// --------------------------------------------------
// Fill Level
//
// The fill level is calculated from the next write
// and read pointers to avoid unnecessary latency
// and logic.
//
// However, if the store-and-forward mode of the FIFO
// is enabled, the fill level is an up-down counter
// for fmax optimization reasons.
//
// If the output pipeline is enabled, the fill level
// must account for it, or we'll always be off by one.
// This may, or may not be important depending on the
// application.
//
// For now, we'll always calculate the exact fill level
// at the cost of an extra adder when the output stage
// is enabled.
// --------------------------------------------------
generate if (USE_FILL_LEVEL) begin : gen_blk16
wire [31:0] depth32;
assign depth32 = DEPTH;
if (USE_STORE_FORWARD) begin
reg [ADDR_WIDTH : 0] curr_packet_len_less_one;
// --------------------------------------------------
// We only drop on endofpacket. As long as we don't add to the fill
// level on the dropped endofpacket cycle, we can simply subtract
// (packet length - 1) from the fill level for dropped packets.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
curr_packet_len_less_one <= 0;
end else begin
if (write) begin
curr_packet_len_less_one <= curr_packet_len_less_one + 1'b1;
if (in_endofpacket)
curr_packet_len_less_one <= 0;
end
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
fifo_fill_level <= 0;
end else if (drop_on_error) begin
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one;
if (read)
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one - 1'b1;
end else if (write && !read) begin
fifo_fill_level <= fifo_fill_level + 1'b1;
end else if (read && !write) begin
fifo_fill_level <= fifo_fill_level - 1'b1;
end
end
end else begin
always @(posedge clk or posedge reset) begin
if (reset)
fifo_fill_level <= 0;
else if (next_full & !drop_on_error)
fifo_fill_level <= depth32[ADDR_WIDTH:0];
else begin
fifo_fill_level[ADDR_WIDTH] <= 1'b0;
fifo_fill_level[ADDR_WIDTH-1 : 0] <= next_wr_ptr - next_rd_ptr;
end
end
end
always @* begin
fill_level = fifo_fill_level;
if (EMPTY_LATENCY == 3)
fill_level = fifo_fill_level + {{ADDR_WIDTH{1'b0}}, out_valid};
end
end
else begin : gen_blk16_else
always @* begin
fill_level = 0;
end
end
endgenerate
generate if (USE_ALMOST_FULL_IF) begin : gen_blk17
assign almost_full_data = (fill_level >= almost_full_threshold);
end
else
assign almost_full_data = 0;
endgenerate
generate if (USE_ALMOST_EMPTY_IF) begin : gen_blk18
assign almost_empty_data = (fill_level <= almost_empty_threshold);
end
else
assign almost_empty_data = 0;
endgenerate
// --------------------------------------------------
// Avalon-MM Status & Control Connection Point
//
// Register map:
//
// | Addr | RW | 31 - 0 |
// | 0 | R | Fill level |
//
// The registering of this connection point means
// that there is a cycle of latency between
// reads/writes and the updating of the fill level.
// --------------------------------------------------
generate if (USE_STORE_FORWARD) begin : gen_blk19
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
cut_through_threshold <= 0;
drop_on_error_en <= 0;
csr_readdata <= 0;
pkt_mode <= 1'b1;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 5)
csr_readdata <= {31'b0, drop_on_error_en};
else if (csr_address == 4)
csr_readdata <= {8'b0, cut_through_threshold};
else if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b101)
drop_on_error_en <= csr_writedata[0];
else if(csr_address == 3'b100) begin
cut_through_threshold <= csr_writedata[23:0];
pkt_mode <= (csr_writedata[23:0] == 0);
end
else if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else if (USE_ALMOST_FULL_IF || USE_ALMOST_EMPTY_IF) begin : gen_blk19_else1
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
csr_readdata <= 0;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else begin : gen_blk19_else2
always @(posedge clk or posedge reset) begin
if (reset) begin
csr_readdata <= 0;
end
else if (csr_read) begin
csr_readdata <= 0;
if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
end
end
endgenerate
// --------------------------------------------------
// Store and forward logic
// --------------------------------------------------
// if the fifo gets full before the entire packet or the
// cut-threshold condition is met then start sending out
// data in order to avoid dead-lock situation
generate if (USE_STORE_FORWARD) begin : gen_blk20
assign wait_for_threshold = (fifo_fill_level_lt_cut_through_threshold) & wait_for_pkt ;
assign wait_for_pkt = pkt_cnt_eq_zero | (pkt_cnt_eq_one & out_pkt_leave);
assign ok_to_forward = (pkt_mode ? (~wait_for_pkt | ~pkt_has_started) :
~wait_for_threshold) | fifo_too_small_r;
assign in_pkt_eop_arrive = in_valid & in_ready & in_endofpacket;
assign in_pkt_start = in_valid & in_ready & in_startofpacket;
assign in_pkt_error = in_valid & in_ready & |in_error;
assign out_pkt_sop_leave = out_valid & out_ready & out_startofpacket;
assign out_pkt_leave = out_valid & out_ready & out_endofpacket;
assign fifo_too_small = (pkt_mode ? wait_for_pkt : wait_for_threshold) & full & out_ready;
// count packets coming and going into the fifo
always @(posedge clk or posedge reset) begin
if (reset) begin
pkt_cnt <= 0;
pkt_has_started <= 0;
sop_has_left_fifo <= 0;
fifo_too_small_r <= 0;
pkt_cnt_eq_zero <= 1'b1;
pkt_cnt_eq_one <= 1'b0;
fifo_fill_level_lt_cut_through_threshold <= 1'b1;
end
else begin
fifo_fill_level_lt_cut_through_threshold <= fifo_fill_level < cut_through_threshold;
fifo_too_small_r <= fifo_too_small;
if( in_pkt_eop_arrive )
sop_has_left_fifo <= 1'b0;
else if (out_pkt_sop_leave & pkt_cnt_eq_zero )
sop_has_left_fifo <= 1'b1;
if (in_pkt_eop_arrive & ~out_pkt_leave & ~drop_on_error ) begin
pkt_cnt <= pkt_cnt + 1'b1;
pkt_cnt_eq_zero <= 0;
if (pkt_cnt == 0)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
else if((~in_pkt_eop_arrive | drop_on_error) & out_pkt_leave) begin
pkt_cnt <= pkt_cnt - 1'b1;
if (pkt_cnt == 1)
pkt_cnt_eq_zero <= 1'b1;
else
pkt_cnt_eq_zero <= 1'b0;
if (pkt_cnt == 2)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
if (in_pkt_start)
pkt_has_started <= 1'b1;
else if (in_pkt_eop_arrive)
pkt_has_started <= 1'b0;
end
end
// drop on error logic
always @(posedge clk or posedge reset) begin
if (reset) begin
sop_ptr <= 0;
error_in_pkt <= 0;
end
else begin
// save the location of the SOP
if ( in_pkt_start )
sop_ptr <= wr_ptr;
// remember if error in pkt
// log error only if packet has already started
if (in_pkt_eop_arrive)
error_in_pkt <= 1'b0;
else if ( in_pkt_error & (pkt_has_started | in_pkt_start))
error_in_pkt <= 1'b1;
end
end
assign drop_on_error = drop_on_error_en & (error_in_pkt | in_pkt_error) & in_pkt_eop_arrive &
~sop_has_left_fifo & ~(out_pkt_sop_leave & pkt_cnt_eq_zero);
assign curr_sop_ptr = (write && in_startofpacket && in_endofpacket) ? wr_ptr : sop_ptr;
end
else begin : gen_blk20_else
assign ok_to_forward = 1'b1;
assign drop_on_error = 1'b0;
if (ADDR_WIDTH <= 1)
assign curr_sop_ptr = 1'b0;
else
assign curr_sop_ptr = {ADDR_WIDTH - 1 { 1'b0 }};
end
endgenerate
// --------------------------------------------------
// Calculates the log2ceil of the input value
// --------------------------------------------------
function integer log2ceil;
input integer val;
reg[31:0] i;
begin
i = 1;
log2ceil = 0;
while (i < val) begin
log2ceil = log2ceil + 1;
i = i[30:0] << 1;
end
end
endfunction
endmodule |
module altera_avalon_sc_fifo
#(
// --------------------------------------------------
// Parameters
// --------------------------------------------------
parameter SYMBOLS_PER_BEAT = 1,
parameter BITS_PER_SYMBOL = 8,
parameter FIFO_DEPTH = 16,
parameter CHANNEL_WIDTH = 0,
parameter ERROR_WIDTH = 0,
parameter USE_PACKETS = 0,
parameter USE_FILL_LEVEL = 0,
parameter USE_STORE_FORWARD = 0,
parameter USE_ALMOST_FULL_IF = 0,
parameter USE_ALMOST_EMPTY_IF = 0,
// --------------------------------------------------
// Empty latency is defined as the number of cycles
// required for a write to deassert the empty flag.
// For example, a latency of 1 means that the empty
// flag is deasserted on the cycle after a write.
//
// Another way to think of it is the latency for a
// write to propagate to the output.
//
// An empty latency of 0 implies lookahead, which is
// only implemented for the register-based FIFO.
// --------------------------------------------------
parameter EMPTY_LATENCY = 3,
parameter USE_MEMORY_BLOCKS = 1,
// --------------------------------------------------
// Internal Parameters
// --------------------------------------------------
parameter DATA_WIDTH = SYMBOLS_PER_BEAT * BITS_PER_SYMBOL,
parameter EMPTY_WIDTH = log2ceil(SYMBOLS_PER_BEAT)
)
(
// --------------------------------------------------
// Ports
// --------------------------------------------------
input clk,
input reset,
input [DATA_WIDTH-1: 0] in_data,
input in_valid,
input in_startofpacket,
input in_endofpacket,
input [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] in_empty,
input [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] in_error,
input [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] in_channel,
output in_ready,
output [DATA_WIDTH-1 : 0] out_data,
output reg out_valid,
output out_startofpacket,
output out_endofpacket,
output [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] out_empty,
output [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] out_error,
output [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] out_channel,
input out_ready,
input [(USE_STORE_FORWARD ? 2 : 1) : 0] csr_address,
input csr_write,
input csr_read,
input [31 : 0] csr_writedata,
output reg [31 : 0] csr_readdata,
output wire almost_full_data,
output wire almost_empty_data
);
// --------------------------------------------------
// Local Parameters
// --------------------------------------------------
localparam ADDR_WIDTH = log2ceil(FIFO_DEPTH);
localparam DEPTH = FIFO_DEPTH;
localparam PKT_SIGNALS_WIDTH = 2 + EMPTY_WIDTH;
localparam PAYLOAD_WIDTH = (USE_PACKETS == 1) ?
2 + EMPTY_WIDTH + DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH:
DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH;
// --------------------------------------------------
// Internal Signals
// --------------------------------------------------
genvar i;
reg [PAYLOAD_WIDTH-1 : 0] mem [DEPTH-1 : 0];
reg [ADDR_WIDTH-1 : 0] wr_ptr;
reg [ADDR_WIDTH-1 : 0] rd_ptr;
reg [DEPTH-1 : 0] mem_used;
wire [ADDR_WIDTH-1 : 0] next_wr_ptr;
wire [ADDR_WIDTH-1 : 0] next_rd_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_wr_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_rd_ptr;
wire [ADDR_WIDTH-1 : 0] mem_rd_ptr;
wire read;
wire write;
reg empty;
reg next_empty;
reg full;
reg next_full;
wire [PKT_SIGNALS_WIDTH-1 : 0] in_packet_signals;
wire [PKT_SIGNALS_WIDTH-1 : 0] out_packet_signals;
wire [PAYLOAD_WIDTH-1 : 0] in_payload;
reg [PAYLOAD_WIDTH-1 : 0] internal_out_payload;
reg [PAYLOAD_WIDTH-1 : 0] out_payload;
reg internal_out_valid;
wire internal_out_ready;
reg [ADDR_WIDTH : 0] fifo_fill_level;
reg [ADDR_WIDTH : 0] fill_level;
reg [ADDR_WIDTH-1 : 0] sop_ptr = 0;
wire [ADDR_WIDTH-1 : 0] curr_sop_ptr;
reg [23:0] almost_full_threshold;
reg [23:0] almost_empty_threshold;
reg [23:0] cut_through_threshold;
reg [15:0] pkt_cnt;
reg drop_on_error_en;
reg error_in_pkt;
reg pkt_has_started;
reg sop_has_left_fifo;
reg fifo_too_small_r;
reg pkt_cnt_eq_zero;
reg pkt_cnt_eq_one;
wire wait_for_threshold;
reg pkt_mode;
wire wait_for_pkt;
wire ok_to_forward;
wire in_pkt_eop_arrive;
wire out_pkt_leave;
wire in_pkt_start;
wire in_pkt_error;
wire drop_on_error;
wire fifo_too_small;
wire out_pkt_sop_leave;
wire [31:0] max_fifo_size;
reg fifo_fill_level_lt_cut_through_threshold;
// --------------------------------------------------
// Define Payload
//
// Icky part where we decide which signals form the
// payload to the FIFO with generate blocks.
// --------------------------------------------------
generate
if (EMPTY_WIDTH > 0) begin : gen_blk1
assign in_packet_signals = {in_startofpacket, in_endofpacket, in_empty};
assign {out_startofpacket, out_endofpacket, out_empty} = out_packet_signals;
end
else begin : gen_blk1_else
assign out_empty = in_error;
assign in_packet_signals = {in_startofpacket, in_endofpacket};
assign {out_startofpacket, out_endofpacket} = out_packet_signals;
end
endgenerate
generate
if (USE_PACKETS) begin : gen_blk2
if (ERROR_WIDTH > 0) begin : gen_blk3
if (CHANNEL_WIDTH > 0) begin : gen_blk4
assign in_payload = {in_packet_signals, in_data, in_error, in_channel};
assign {out_packet_signals, out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk4_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data, in_error};
assign {out_packet_signals, out_data, out_error} = out_payload;
end
end
else begin : gen_blk3_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk5
assign in_payload = {in_packet_signals, in_data, in_channel};
assign {out_packet_signals, out_data, out_channel} = out_payload;
end
else begin : gen_blk5_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data};
assign {out_packet_signals, out_data} = out_payload;
end
end
end
else begin : gen_blk2_else
assign out_packet_signals = 0;
if (ERROR_WIDTH > 0) begin : gen_blk6
if (CHANNEL_WIDTH > 0) begin : gen_blk7
assign in_payload = {in_data, in_error, in_channel};
assign {out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk7_else
assign out_channel = in_channel;
assign in_payload = {in_data, in_error};
assign {out_data, out_error} = out_payload;
end
end
else begin : gen_blk6_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk8
assign in_payload = {in_data, in_channel};
assign {out_data, out_channel} = out_payload;
end
else begin : gen_blk8_else
assign out_channel = in_channel;
assign in_payload = in_data;
assign out_data = out_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Memory-based FIFO storage
//
// To allow a ready latency of 0, the read index is
// obtained from the next read pointer and memory
// outputs are unregistered.
//
// If the empty latency is 1, we infer bypass logic
// around the memory so writes propagate to the
// outputs on the next cycle.
//
// Do not change the way this is coded: Quartus needs
// a perfect match to the template, and any attempt to
// refactor the two always blocks into one will break
// memory inference.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk9
if (EMPTY_LATENCY == 1) begin : gen_blk10
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] = in_payload;
internal_out_payload = mem[mem_rd_ptr];
end
end else begin : gen_blk10_else
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] <= in_payload;
internal_out_payload <= mem[mem_rd_ptr];
end
end
assign mem_rd_ptr = next_rd_ptr;
end else begin : gen_blk9_else
// --------------------------------------------------
// Register-based FIFO storage
//
// Uses a shift register as the storage element. Each
// shift register slot has a bit which indicates if
// the slot is occupied (credit to Sam H for the idea).
// The occupancy bits are contiguous and start from the
// lsb, so 0000, 0001, 0011, 0111, 1111 for a 4-deep
// FIFO.
//
// Each slot is enabled during a read or when it
// is unoccupied. New data is always written to every
// going-to-be-empty slot (we keep track of which ones
// are actually useful with the occupancy bits). On a
// read we shift occupied slots.
//
// The exception is the last slot, which always gets
// new data when it is unoccupied.
// --------------------------------------------------
for (i = 0; i < DEPTH-1; i = i + 1) begin : shift_reg
always @(posedge clk or posedge reset) begin
if (reset) begin
mem[i] <= 0;
end
else if (read || !mem_used[i]) begin
if (!mem_used[i+1])
mem[i] <= in_payload;
else
mem[i] <= mem[i+1];
end
end
end
always @(posedge clk, posedge reset) begin
if (reset) begin
mem[DEPTH-1] <= 0;
end
else begin
if (DEPTH == 1) begin
if (write)
mem[DEPTH-1] <= in_payload;
end
else if (!mem_used[DEPTH-1])
mem[DEPTH-1] <= in_payload;
end
end
end
endgenerate
assign read = internal_out_ready && internal_out_valid && ok_to_forward;
assign write = in_ready && in_valid;
// --------------------------------------------------
// Pointer Management
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk11
assign incremented_wr_ptr = wr_ptr + 1'b1;
assign incremented_rd_ptr = rd_ptr + 1'b1;
assign next_wr_ptr = drop_on_error ? curr_sop_ptr : write ? incremented_wr_ptr : wr_ptr;
assign next_rd_ptr = (read) ? incremented_rd_ptr : rd_ptr;
always @(posedge clk or posedge reset) begin
if (reset) begin
wr_ptr <= 0;
rd_ptr <= 0;
end
else begin
wr_ptr <= next_wr_ptr;
rd_ptr <= next_rd_ptr;
end
end
end else begin : gen_blk11_else
// --------------------------------------------------
// Shift Register Occupancy Bits
//
// Consider a 4-deep FIFO with 2 entries: 0011
// On a read and write, do not modify the bits.
// On a write, left-shift the bits to get 0111.
// On a read, right-shift the bits to get 0001.
//
// Also, on a write we set bit0 (the head), while
// clearing the tail on a read.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[0] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[0] <= 1;
else if (read) begin
if (DEPTH > 1)
mem_used[0] <= mem_used[1];
else
mem_used[0] <= 0;
end
end
end
end
if (DEPTH > 1) begin : gen_blk12
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[DEPTH-1] <= 0;
end
else begin
if (write ^ read) begin
mem_used[DEPTH-1] <= 0;
if (write)
mem_used[DEPTH-1] <= mem_used[DEPTH-2];
end
end
end
end
for (i = 1; i < DEPTH-1; i = i + 1) begin : storage_logic
always @(posedge clk, posedge reset) begin
if (reset) begin
mem_used[i] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[i] <= mem_used[i-1];
else if (read)
mem_used[i] <= mem_used[i+1];
end
end
end
end
end
endgenerate
// --------------------------------------------------
// Memory FIFO Status Management
//
// Generates the full and empty signals from the
// pointers. The FIFO is full when the next write
// pointer will be equal to the read pointer after
// a write. Reading from a FIFO clears full.
//
// The FIFO is empty when the next read pointer will
// be equal to the write pointer after a read. Writing
// to a FIFO clears empty.
//
// A simultaneous read and write must not change any of
// the empty or full flags unless there is a drop on error event.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk13
always @* begin
next_full = full;
next_empty = empty;
if (read && !write) begin
next_full = 1'b0;
if (incremented_rd_ptr == wr_ptr)
next_empty = 1'b1;
end
if (write && !read) begin
if (!drop_on_error)
next_empty = 1'b0;
else if (curr_sop_ptr == rd_ptr) // drop on error and only 1 pkt in fifo
next_empty = 1'b1;
if (incremented_wr_ptr == rd_ptr && !drop_on_error)
next_full = 1'b1;
end
if (write && read && drop_on_error) begin
if (curr_sop_ptr == next_rd_ptr)
next_empty = 1'b1;
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
empty <= 1;
full <= 0;
end
else begin
empty <= next_empty;
full <= next_full;
end
end
end else begin : gen_blk13_else
// --------------------------------------------------
// Register FIFO Status Management
//
// Full when the tail occupancy bit is 1. Empty when
// the head occupancy bit is 0.
// --------------------------------------------------
always @* begin
full = mem_used[DEPTH-1];
empty = !mem_used[0];
// ------------------------------------------
// For a single slot FIFO, reading clears the
// full status immediately.
// ------------------------------------------
if (DEPTH == 1)
full = mem_used[0] && !read;
internal_out_payload = mem[0];
// ------------------------------------------
// Writes clear empty immediately for lookahead modes.
// Note that we use in_valid instead of write to avoid
// combinational loops (in lookahead mode, qualifying
// with in_ready is meaningless).
//
// In a 1-deep FIFO, a possible combinational loop runs
// from write -> out_valid -> out_ready -> write
// ------------------------------------------
if (EMPTY_LATENCY == 0) begin
empty = !mem_used[0] && !in_valid;
if (!mem_used[0] && in_valid)
internal_out_payload = in_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Avalon-ST Signals
//
// The in_ready signal is straightforward.
//
// To match memory latency when empty latency > 1,
// out_valid assertions must be delayed by one clock
// cycle.
//
// Note: out_valid deassertions must not be delayed or
// the FIFO will underflow.
// --------------------------------------------------
assign in_ready = !full;
assign internal_out_ready = out_ready || !out_valid;
generate if (EMPTY_LATENCY > 1) begin : gen_blk14
always @(posedge clk or posedge reset) begin
if (reset)
internal_out_valid <= 0;
else begin
internal_out_valid <= !empty & ok_to_forward & ~drop_on_error;
if (read) begin
if (incremented_rd_ptr == wr_ptr)
internal_out_valid <= 1'b0;
end
end
end
end else begin : gen_blk14_else
always @* begin
internal_out_valid = !empty & ok_to_forward;
end
end
endgenerate
// --------------------------------------------------
// Single Output Pipeline Stage
//
// This output pipeline stage is enabled if the FIFO's
// empty latency is set to 3 (default). It is disabled
// for all other allowed latencies.
//
// Reason: The memory outputs are unregistered, so we have to
// register the output or fmax will drop if combinatorial
// logic is present on the output datapath.
//
// Q: The Avalon-ST spec says that I have to register my outputs
// But isn't the memory counted as a register?
// A: The path from the address lookup to the memory output is
// slow. Registering the memory outputs is a good idea.
//
// The registers get packed into the memory by the fitter
// which means minimal resources are consumed (the result
// is a altsyncram with registered outputs, available on
// all modern Altera devices).
//
// This output stage acts as an extra slot in the FIFO,
// and complicates the fill level.
// --------------------------------------------------
generate if (EMPTY_LATENCY == 3) begin : gen_blk15
always @(posedge clk or posedge reset) begin
if (reset) begin
out_valid <= 0;
out_payload <= 0;
end
else begin
if (internal_out_ready) begin
out_valid <= internal_out_valid & ok_to_forward;
out_payload <= internal_out_payload;
end
end
end
end
else begin : gen_blk15_else
always @* begin
out_valid = internal_out_valid;
out_payload = internal_out_payload;
end
end
endgenerate
// --------------------------------------------------
// Fill Level
//
// The fill level is calculated from the next write
// and read pointers to avoid unnecessary latency
// and logic.
//
// However, if the store-and-forward mode of the FIFO
// is enabled, the fill level is an up-down counter
// for fmax optimization reasons.
//
// If the output pipeline is enabled, the fill level
// must account for it, or we'll always be off by one.
// This may, or may not be important depending on the
// application.
//
// For now, we'll always calculate the exact fill level
// at the cost of an extra adder when the output stage
// is enabled.
// --------------------------------------------------
generate if (USE_FILL_LEVEL) begin : gen_blk16
wire [31:0] depth32;
assign depth32 = DEPTH;
if (USE_STORE_FORWARD) begin
reg [ADDR_WIDTH : 0] curr_packet_len_less_one;
// --------------------------------------------------
// We only drop on endofpacket. As long as we don't add to the fill
// level on the dropped endofpacket cycle, we can simply subtract
// (packet length - 1) from the fill level for dropped packets.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
curr_packet_len_less_one <= 0;
end else begin
if (write) begin
curr_packet_len_less_one <= curr_packet_len_less_one + 1'b1;
if (in_endofpacket)
curr_packet_len_less_one <= 0;
end
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
fifo_fill_level <= 0;
end else if (drop_on_error) begin
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one;
if (read)
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one - 1'b1;
end else if (write && !read) begin
fifo_fill_level <= fifo_fill_level + 1'b1;
end else if (read && !write) begin
fifo_fill_level <= fifo_fill_level - 1'b1;
end
end
end else begin
always @(posedge clk or posedge reset) begin
if (reset)
fifo_fill_level <= 0;
else if (next_full & !drop_on_error)
fifo_fill_level <= depth32[ADDR_WIDTH:0];
else begin
fifo_fill_level[ADDR_WIDTH] <= 1'b0;
fifo_fill_level[ADDR_WIDTH-1 : 0] <= next_wr_ptr - next_rd_ptr;
end
end
end
always @* begin
fill_level = fifo_fill_level;
if (EMPTY_LATENCY == 3)
fill_level = fifo_fill_level + {{ADDR_WIDTH{1'b0}}, out_valid};
end
end
else begin : gen_blk16_else
always @* begin
fill_level = 0;
end
end
endgenerate
generate if (USE_ALMOST_FULL_IF) begin : gen_blk17
assign almost_full_data = (fill_level >= almost_full_threshold);
end
else
assign almost_full_data = 0;
endgenerate
generate if (USE_ALMOST_EMPTY_IF) begin : gen_blk18
assign almost_empty_data = (fill_level <= almost_empty_threshold);
end
else
assign almost_empty_data = 0;
endgenerate
// --------------------------------------------------
// Avalon-MM Status & Control Connection Point
//
// Register map:
//
// | Addr | RW | 31 - 0 |
// | 0 | R | Fill level |
//
// The registering of this connection point means
// that there is a cycle of latency between
// reads/writes and the updating of the fill level.
// --------------------------------------------------
generate if (USE_STORE_FORWARD) begin : gen_blk19
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
cut_through_threshold <= 0;
drop_on_error_en <= 0;
csr_readdata <= 0;
pkt_mode <= 1'b1;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 5)
csr_readdata <= {31'b0, drop_on_error_en};
else if (csr_address == 4)
csr_readdata <= {8'b0, cut_through_threshold};
else if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b101)
drop_on_error_en <= csr_writedata[0];
else if(csr_address == 3'b100) begin
cut_through_threshold <= csr_writedata[23:0];
pkt_mode <= (csr_writedata[23:0] == 0);
end
else if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else if (USE_ALMOST_FULL_IF || USE_ALMOST_EMPTY_IF) begin : gen_blk19_else1
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
csr_readdata <= 0;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else begin : gen_blk19_else2
always @(posedge clk or posedge reset) begin
if (reset) begin
csr_readdata <= 0;
end
else if (csr_read) begin
csr_readdata <= 0;
if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
end
end
endgenerate
// --------------------------------------------------
// Store and forward logic
// --------------------------------------------------
// if the fifo gets full before the entire packet or the
// cut-threshold condition is met then start sending out
// data in order to avoid dead-lock situation
generate if (USE_STORE_FORWARD) begin : gen_blk20
assign wait_for_threshold = (fifo_fill_level_lt_cut_through_threshold) & wait_for_pkt ;
assign wait_for_pkt = pkt_cnt_eq_zero | (pkt_cnt_eq_one & out_pkt_leave);
assign ok_to_forward = (pkt_mode ? (~wait_for_pkt | ~pkt_has_started) :
~wait_for_threshold) | fifo_too_small_r;
assign in_pkt_eop_arrive = in_valid & in_ready & in_endofpacket;
assign in_pkt_start = in_valid & in_ready & in_startofpacket;
assign in_pkt_error = in_valid & in_ready & |in_error;
assign out_pkt_sop_leave = out_valid & out_ready & out_startofpacket;
assign out_pkt_leave = out_valid & out_ready & out_endofpacket;
assign fifo_too_small = (pkt_mode ? wait_for_pkt : wait_for_threshold) & full & out_ready;
// count packets coming and going into the fifo
always @(posedge clk or posedge reset) begin
if (reset) begin
pkt_cnt <= 0;
pkt_has_started <= 0;
sop_has_left_fifo <= 0;
fifo_too_small_r <= 0;
pkt_cnt_eq_zero <= 1'b1;
pkt_cnt_eq_one <= 1'b0;
fifo_fill_level_lt_cut_through_threshold <= 1'b1;
end
else begin
fifo_fill_level_lt_cut_through_threshold <= fifo_fill_level < cut_through_threshold;
fifo_too_small_r <= fifo_too_small;
if( in_pkt_eop_arrive )
sop_has_left_fifo <= 1'b0;
else if (out_pkt_sop_leave & pkt_cnt_eq_zero )
sop_has_left_fifo <= 1'b1;
if (in_pkt_eop_arrive & ~out_pkt_leave & ~drop_on_error ) begin
pkt_cnt <= pkt_cnt + 1'b1;
pkt_cnt_eq_zero <= 0;
if (pkt_cnt == 0)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
else if((~in_pkt_eop_arrive | drop_on_error) & out_pkt_leave) begin
pkt_cnt <= pkt_cnt - 1'b1;
if (pkt_cnt == 1)
pkt_cnt_eq_zero <= 1'b1;
else
pkt_cnt_eq_zero <= 1'b0;
if (pkt_cnt == 2)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
if (in_pkt_start)
pkt_has_started <= 1'b1;
else if (in_pkt_eop_arrive)
pkt_has_started <= 1'b0;
end
end
// drop on error logic
always @(posedge clk or posedge reset) begin
if (reset) begin
sop_ptr <= 0;
error_in_pkt <= 0;
end
else begin
// save the location of the SOP
if ( in_pkt_start )
sop_ptr <= wr_ptr;
// remember if error in pkt
// log error only if packet has already started
if (in_pkt_eop_arrive)
error_in_pkt <= 1'b0;
else if ( in_pkt_error & (pkt_has_started | in_pkt_start))
error_in_pkt <= 1'b1;
end
end
assign drop_on_error = drop_on_error_en & (error_in_pkt | in_pkt_error) & in_pkt_eop_arrive &
~sop_has_left_fifo & ~(out_pkt_sop_leave & pkt_cnt_eq_zero);
assign curr_sop_ptr = (write && in_startofpacket && in_endofpacket) ? wr_ptr : sop_ptr;
end
else begin : gen_blk20_else
assign ok_to_forward = 1'b1;
assign drop_on_error = 1'b0;
if (ADDR_WIDTH <= 1)
assign curr_sop_ptr = 1'b0;
else
assign curr_sop_ptr = {ADDR_WIDTH - 1 { 1'b0 }};
end
endgenerate
// --------------------------------------------------
// Calculates the log2ceil of the input value
// --------------------------------------------------
function integer log2ceil;
input integer val;
reg[31:0] i;
begin
i = 1;
log2ceil = 0;
while (i < val) begin
log2ceil = log2ceil + 1;
i = i[30:0] << 1;
end
end
endfunction
endmodule |
module altera_avalon_sc_fifo
#(
// --------------------------------------------------
// Parameters
// --------------------------------------------------
parameter SYMBOLS_PER_BEAT = 1,
parameter BITS_PER_SYMBOL = 8,
parameter FIFO_DEPTH = 16,
parameter CHANNEL_WIDTH = 0,
parameter ERROR_WIDTH = 0,
parameter USE_PACKETS = 0,
parameter USE_FILL_LEVEL = 0,
parameter USE_STORE_FORWARD = 0,
parameter USE_ALMOST_FULL_IF = 0,
parameter USE_ALMOST_EMPTY_IF = 0,
// --------------------------------------------------
// Empty latency is defined as the number of cycles
// required for a write to deassert the empty flag.
// For example, a latency of 1 means that the empty
// flag is deasserted on the cycle after a write.
//
// Another way to think of it is the latency for a
// write to propagate to the output.
//
// An empty latency of 0 implies lookahead, which is
// only implemented for the register-based FIFO.
// --------------------------------------------------
parameter EMPTY_LATENCY = 3,
parameter USE_MEMORY_BLOCKS = 1,
// --------------------------------------------------
// Internal Parameters
// --------------------------------------------------
parameter DATA_WIDTH = SYMBOLS_PER_BEAT * BITS_PER_SYMBOL,
parameter EMPTY_WIDTH = log2ceil(SYMBOLS_PER_BEAT)
)
(
// --------------------------------------------------
// Ports
// --------------------------------------------------
input clk,
input reset,
input [DATA_WIDTH-1: 0] in_data,
input in_valid,
input in_startofpacket,
input in_endofpacket,
input [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] in_empty,
input [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] in_error,
input [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] in_channel,
output in_ready,
output [DATA_WIDTH-1 : 0] out_data,
output reg out_valid,
output out_startofpacket,
output out_endofpacket,
output [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] out_empty,
output [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] out_error,
output [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] out_channel,
input out_ready,
input [(USE_STORE_FORWARD ? 2 : 1) : 0] csr_address,
input csr_write,
input csr_read,
input [31 : 0] csr_writedata,
output reg [31 : 0] csr_readdata,
output wire almost_full_data,
output wire almost_empty_data
);
// --------------------------------------------------
// Local Parameters
// --------------------------------------------------
localparam ADDR_WIDTH = log2ceil(FIFO_DEPTH);
localparam DEPTH = FIFO_DEPTH;
localparam PKT_SIGNALS_WIDTH = 2 + EMPTY_WIDTH;
localparam PAYLOAD_WIDTH = (USE_PACKETS == 1) ?
2 + EMPTY_WIDTH + DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH:
DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH;
// --------------------------------------------------
// Internal Signals
// --------------------------------------------------
genvar i;
reg [PAYLOAD_WIDTH-1 : 0] mem [DEPTH-1 : 0];
reg [ADDR_WIDTH-1 : 0] wr_ptr;
reg [ADDR_WIDTH-1 : 0] rd_ptr;
reg [DEPTH-1 : 0] mem_used;
wire [ADDR_WIDTH-1 : 0] next_wr_ptr;
wire [ADDR_WIDTH-1 : 0] next_rd_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_wr_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_rd_ptr;
wire [ADDR_WIDTH-1 : 0] mem_rd_ptr;
wire read;
wire write;
reg empty;
reg next_empty;
reg full;
reg next_full;
wire [PKT_SIGNALS_WIDTH-1 : 0] in_packet_signals;
wire [PKT_SIGNALS_WIDTH-1 : 0] out_packet_signals;
wire [PAYLOAD_WIDTH-1 : 0] in_payload;
reg [PAYLOAD_WIDTH-1 : 0] internal_out_payload;
reg [PAYLOAD_WIDTH-1 : 0] out_payload;
reg internal_out_valid;
wire internal_out_ready;
reg [ADDR_WIDTH : 0] fifo_fill_level;
reg [ADDR_WIDTH : 0] fill_level;
reg [ADDR_WIDTH-1 : 0] sop_ptr = 0;
wire [ADDR_WIDTH-1 : 0] curr_sop_ptr;
reg [23:0] almost_full_threshold;
reg [23:0] almost_empty_threshold;
reg [23:0] cut_through_threshold;
reg [15:0] pkt_cnt;
reg drop_on_error_en;
reg error_in_pkt;
reg pkt_has_started;
reg sop_has_left_fifo;
reg fifo_too_small_r;
reg pkt_cnt_eq_zero;
reg pkt_cnt_eq_one;
wire wait_for_threshold;
reg pkt_mode;
wire wait_for_pkt;
wire ok_to_forward;
wire in_pkt_eop_arrive;
wire out_pkt_leave;
wire in_pkt_start;
wire in_pkt_error;
wire drop_on_error;
wire fifo_too_small;
wire out_pkt_sop_leave;
wire [31:0] max_fifo_size;
reg fifo_fill_level_lt_cut_through_threshold;
// --------------------------------------------------
// Define Payload
//
// Icky part where we decide which signals form the
// payload to the FIFO with generate blocks.
// --------------------------------------------------
generate
if (EMPTY_WIDTH > 0) begin : gen_blk1
assign in_packet_signals = {in_startofpacket, in_endofpacket, in_empty};
assign {out_startofpacket, out_endofpacket, out_empty} = out_packet_signals;
end
else begin : gen_blk1_else
assign out_empty = in_error;
assign in_packet_signals = {in_startofpacket, in_endofpacket};
assign {out_startofpacket, out_endofpacket} = out_packet_signals;
end
endgenerate
generate
if (USE_PACKETS) begin : gen_blk2
if (ERROR_WIDTH > 0) begin : gen_blk3
if (CHANNEL_WIDTH > 0) begin : gen_blk4
assign in_payload = {in_packet_signals, in_data, in_error, in_channel};
assign {out_packet_signals, out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk4_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data, in_error};
assign {out_packet_signals, out_data, out_error} = out_payload;
end
end
else begin : gen_blk3_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk5
assign in_payload = {in_packet_signals, in_data, in_channel};
assign {out_packet_signals, out_data, out_channel} = out_payload;
end
else begin : gen_blk5_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data};
assign {out_packet_signals, out_data} = out_payload;
end
end
end
else begin : gen_blk2_else
assign out_packet_signals = 0;
if (ERROR_WIDTH > 0) begin : gen_blk6
if (CHANNEL_WIDTH > 0) begin : gen_blk7
assign in_payload = {in_data, in_error, in_channel};
assign {out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk7_else
assign out_channel = in_channel;
assign in_payload = {in_data, in_error};
assign {out_data, out_error} = out_payload;
end
end
else begin : gen_blk6_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk8
assign in_payload = {in_data, in_channel};
assign {out_data, out_channel} = out_payload;
end
else begin : gen_blk8_else
assign out_channel = in_channel;
assign in_payload = in_data;
assign out_data = out_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Memory-based FIFO storage
//
// To allow a ready latency of 0, the read index is
// obtained from the next read pointer and memory
// outputs are unregistered.
//
// If the empty latency is 1, we infer bypass logic
// around the memory so writes propagate to the
// outputs on the next cycle.
//
// Do not change the way this is coded: Quartus needs
// a perfect match to the template, and any attempt to
// refactor the two always blocks into one will break
// memory inference.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk9
if (EMPTY_LATENCY == 1) begin : gen_blk10
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] = in_payload;
internal_out_payload = mem[mem_rd_ptr];
end
end else begin : gen_blk10_else
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] <= in_payload;
internal_out_payload <= mem[mem_rd_ptr];
end
end
assign mem_rd_ptr = next_rd_ptr;
end else begin : gen_blk9_else
// --------------------------------------------------
// Register-based FIFO storage
//
// Uses a shift register as the storage element. Each
// shift register slot has a bit which indicates if
// the slot is occupied (credit to Sam H for the idea).
// The occupancy bits are contiguous and start from the
// lsb, so 0000, 0001, 0011, 0111, 1111 for a 4-deep
// FIFO.
//
// Each slot is enabled during a read or when it
// is unoccupied. New data is always written to every
// going-to-be-empty slot (we keep track of which ones
// are actually useful with the occupancy bits). On a
// read we shift occupied slots.
//
// The exception is the last slot, which always gets
// new data when it is unoccupied.
// --------------------------------------------------
for (i = 0; i < DEPTH-1; i = i + 1) begin : shift_reg
always @(posedge clk or posedge reset) begin
if (reset) begin
mem[i] <= 0;
end
else if (read || !mem_used[i]) begin
if (!mem_used[i+1])
mem[i] <= in_payload;
else
mem[i] <= mem[i+1];
end
end
end
always @(posedge clk, posedge reset) begin
if (reset) begin
mem[DEPTH-1] <= 0;
end
else begin
if (DEPTH == 1) begin
if (write)
mem[DEPTH-1] <= in_payload;
end
else if (!mem_used[DEPTH-1])
mem[DEPTH-1] <= in_payload;
end
end
end
endgenerate
assign read = internal_out_ready && internal_out_valid && ok_to_forward;
assign write = in_ready && in_valid;
// --------------------------------------------------
// Pointer Management
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk11
assign incremented_wr_ptr = wr_ptr + 1'b1;
assign incremented_rd_ptr = rd_ptr + 1'b1;
assign next_wr_ptr = drop_on_error ? curr_sop_ptr : write ? incremented_wr_ptr : wr_ptr;
assign next_rd_ptr = (read) ? incremented_rd_ptr : rd_ptr;
always @(posedge clk or posedge reset) begin
if (reset) begin
wr_ptr <= 0;
rd_ptr <= 0;
end
else begin
wr_ptr <= next_wr_ptr;
rd_ptr <= next_rd_ptr;
end
end
end else begin : gen_blk11_else
// --------------------------------------------------
// Shift Register Occupancy Bits
//
// Consider a 4-deep FIFO with 2 entries: 0011
// On a read and write, do not modify the bits.
// On a write, left-shift the bits to get 0111.
// On a read, right-shift the bits to get 0001.
//
// Also, on a write we set bit0 (the head), while
// clearing the tail on a read.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[0] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[0] <= 1;
else if (read) begin
if (DEPTH > 1)
mem_used[0] <= mem_used[1];
else
mem_used[0] <= 0;
end
end
end
end
if (DEPTH > 1) begin : gen_blk12
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[DEPTH-1] <= 0;
end
else begin
if (write ^ read) begin
mem_used[DEPTH-1] <= 0;
if (write)
mem_used[DEPTH-1] <= mem_used[DEPTH-2];
end
end
end
end
for (i = 1; i < DEPTH-1; i = i + 1) begin : storage_logic
always @(posedge clk, posedge reset) begin
if (reset) begin
mem_used[i] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[i] <= mem_used[i-1];
else if (read)
mem_used[i] <= mem_used[i+1];
end
end
end
end
end
endgenerate
// --------------------------------------------------
// Memory FIFO Status Management
//
// Generates the full and empty signals from the
// pointers. The FIFO is full when the next write
// pointer will be equal to the read pointer after
// a write. Reading from a FIFO clears full.
//
// The FIFO is empty when the next read pointer will
// be equal to the write pointer after a read. Writing
// to a FIFO clears empty.
//
// A simultaneous read and write must not change any of
// the empty or full flags unless there is a drop on error event.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk13
always @* begin
next_full = full;
next_empty = empty;
if (read && !write) begin
next_full = 1'b0;
if (incremented_rd_ptr == wr_ptr)
next_empty = 1'b1;
end
if (write && !read) begin
if (!drop_on_error)
next_empty = 1'b0;
else if (curr_sop_ptr == rd_ptr) // drop on error and only 1 pkt in fifo
next_empty = 1'b1;
if (incremented_wr_ptr == rd_ptr && !drop_on_error)
next_full = 1'b1;
end
if (write && read && drop_on_error) begin
if (curr_sop_ptr == next_rd_ptr)
next_empty = 1'b1;
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
empty <= 1;
full <= 0;
end
else begin
empty <= next_empty;
full <= next_full;
end
end
end else begin : gen_blk13_else
// --------------------------------------------------
// Register FIFO Status Management
//
// Full when the tail occupancy bit is 1. Empty when
// the head occupancy bit is 0.
// --------------------------------------------------
always @* begin
full = mem_used[DEPTH-1];
empty = !mem_used[0];
// ------------------------------------------
// For a single slot FIFO, reading clears the
// full status immediately.
// ------------------------------------------
if (DEPTH == 1)
full = mem_used[0] && !read;
internal_out_payload = mem[0];
// ------------------------------------------
// Writes clear empty immediately for lookahead modes.
// Note that we use in_valid instead of write to avoid
// combinational loops (in lookahead mode, qualifying
// with in_ready is meaningless).
//
// In a 1-deep FIFO, a possible combinational loop runs
// from write -> out_valid -> out_ready -> write
// ------------------------------------------
if (EMPTY_LATENCY == 0) begin
empty = !mem_used[0] && !in_valid;
if (!mem_used[0] && in_valid)
internal_out_payload = in_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Avalon-ST Signals
//
// The in_ready signal is straightforward.
//
// To match memory latency when empty latency > 1,
// out_valid assertions must be delayed by one clock
// cycle.
//
// Note: out_valid deassertions must not be delayed or
// the FIFO will underflow.
// --------------------------------------------------
assign in_ready = !full;
assign internal_out_ready = out_ready || !out_valid;
generate if (EMPTY_LATENCY > 1) begin : gen_blk14
always @(posedge clk or posedge reset) begin
if (reset)
internal_out_valid <= 0;
else begin
internal_out_valid <= !empty & ok_to_forward & ~drop_on_error;
if (read) begin
if (incremented_rd_ptr == wr_ptr)
internal_out_valid <= 1'b0;
end
end
end
end else begin : gen_blk14_else
always @* begin
internal_out_valid = !empty & ok_to_forward;
end
end
endgenerate
// --------------------------------------------------
// Single Output Pipeline Stage
//
// This output pipeline stage is enabled if the FIFO's
// empty latency is set to 3 (default). It is disabled
// for all other allowed latencies.
//
// Reason: The memory outputs are unregistered, so we have to
// register the output or fmax will drop if combinatorial
// logic is present on the output datapath.
//
// Q: The Avalon-ST spec says that I have to register my outputs
// But isn't the memory counted as a register?
// A: The path from the address lookup to the memory output is
// slow. Registering the memory outputs is a good idea.
//
// The registers get packed into the memory by the fitter
// which means minimal resources are consumed (the result
// is a altsyncram with registered outputs, available on
// all modern Altera devices).
//
// This output stage acts as an extra slot in the FIFO,
// and complicates the fill level.
// --------------------------------------------------
generate if (EMPTY_LATENCY == 3) begin : gen_blk15
always @(posedge clk or posedge reset) begin
if (reset) begin
out_valid <= 0;
out_payload <= 0;
end
else begin
if (internal_out_ready) begin
out_valid <= internal_out_valid & ok_to_forward;
out_payload <= internal_out_payload;
end
end
end
end
else begin : gen_blk15_else
always @* begin
out_valid = internal_out_valid;
out_payload = internal_out_payload;
end
end
endgenerate
// --------------------------------------------------
// Fill Level
//
// The fill level is calculated from the next write
// and read pointers to avoid unnecessary latency
// and logic.
//
// However, if the store-and-forward mode of the FIFO
// is enabled, the fill level is an up-down counter
// for fmax optimization reasons.
//
// If the output pipeline is enabled, the fill level
// must account for it, or we'll always be off by one.
// This may, or may not be important depending on the
// application.
//
// For now, we'll always calculate the exact fill level
// at the cost of an extra adder when the output stage
// is enabled.
// --------------------------------------------------
generate if (USE_FILL_LEVEL) begin : gen_blk16
wire [31:0] depth32;
assign depth32 = DEPTH;
if (USE_STORE_FORWARD) begin
reg [ADDR_WIDTH : 0] curr_packet_len_less_one;
// --------------------------------------------------
// We only drop on endofpacket. As long as we don't add to the fill
// level on the dropped endofpacket cycle, we can simply subtract
// (packet length - 1) from the fill level for dropped packets.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
curr_packet_len_less_one <= 0;
end else begin
if (write) begin
curr_packet_len_less_one <= curr_packet_len_less_one + 1'b1;
if (in_endofpacket)
curr_packet_len_less_one <= 0;
end
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
fifo_fill_level <= 0;
end else if (drop_on_error) begin
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one;
if (read)
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one - 1'b1;
end else if (write && !read) begin
fifo_fill_level <= fifo_fill_level + 1'b1;
end else if (read && !write) begin
fifo_fill_level <= fifo_fill_level - 1'b1;
end
end
end else begin
always @(posedge clk or posedge reset) begin
if (reset)
fifo_fill_level <= 0;
else if (next_full & !drop_on_error)
fifo_fill_level <= depth32[ADDR_WIDTH:0];
else begin
fifo_fill_level[ADDR_WIDTH] <= 1'b0;
fifo_fill_level[ADDR_WIDTH-1 : 0] <= next_wr_ptr - next_rd_ptr;
end
end
end
always @* begin
fill_level = fifo_fill_level;
if (EMPTY_LATENCY == 3)
fill_level = fifo_fill_level + {{ADDR_WIDTH{1'b0}}, out_valid};
end
end
else begin : gen_blk16_else
always @* begin
fill_level = 0;
end
end
endgenerate
generate if (USE_ALMOST_FULL_IF) begin : gen_blk17
assign almost_full_data = (fill_level >= almost_full_threshold);
end
else
assign almost_full_data = 0;
endgenerate
generate if (USE_ALMOST_EMPTY_IF) begin : gen_blk18
assign almost_empty_data = (fill_level <= almost_empty_threshold);
end
else
assign almost_empty_data = 0;
endgenerate
// --------------------------------------------------
// Avalon-MM Status & Control Connection Point
//
// Register map:
//
// | Addr | RW | 31 - 0 |
// | 0 | R | Fill level |
//
// The registering of this connection point means
// that there is a cycle of latency between
// reads/writes and the updating of the fill level.
// --------------------------------------------------
generate if (USE_STORE_FORWARD) begin : gen_blk19
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
cut_through_threshold <= 0;
drop_on_error_en <= 0;
csr_readdata <= 0;
pkt_mode <= 1'b1;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 5)
csr_readdata <= {31'b0, drop_on_error_en};
else if (csr_address == 4)
csr_readdata <= {8'b0, cut_through_threshold};
else if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b101)
drop_on_error_en <= csr_writedata[0];
else if(csr_address == 3'b100) begin
cut_through_threshold <= csr_writedata[23:0];
pkt_mode <= (csr_writedata[23:0] == 0);
end
else if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else if (USE_ALMOST_FULL_IF || USE_ALMOST_EMPTY_IF) begin : gen_blk19_else1
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
csr_readdata <= 0;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else begin : gen_blk19_else2
always @(posedge clk or posedge reset) begin
if (reset) begin
csr_readdata <= 0;
end
else if (csr_read) begin
csr_readdata <= 0;
if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
end
end
endgenerate
// --------------------------------------------------
// Store and forward logic
// --------------------------------------------------
// if the fifo gets full before the entire packet or the
// cut-threshold condition is met then start sending out
// data in order to avoid dead-lock situation
generate if (USE_STORE_FORWARD) begin : gen_blk20
assign wait_for_threshold = (fifo_fill_level_lt_cut_through_threshold) & wait_for_pkt ;
assign wait_for_pkt = pkt_cnt_eq_zero | (pkt_cnt_eq_one & out_pkt_leave);
assign ok_to_forward = (pkt_mode ? (~wait_for_pkt | ~pkt_has_started) :
~wait_for_threshold) | fifo_too_small_r;
assign in_pkt_eop_arrive = in_valid & in_ready & in_endofpacket;
assign in_pkt_start = in_valid & in_ready & in_startofpacket;
assign in_pkt_error = in_valid & in_ready & |in_error;
assign out_pkt_sop_leave = out_valid & out_ready & out_startofpacket;
assign out_pkt_leave = out_valid & out_ready & out_endofpacket;
assign fifo_too_small = (pkt_mode ? wait_for_pkt : wait_for_threshold) & full & out_ready;
// count packets coming and going into the fifo
always @(posedge clk or posedge reset) begin
if (reset) begin
pkt_cnt <= 0;
pkt_has_started <= 0;
sop_has_left_fifo <= 0;
fifo_too_small_r <= 0;
pkt_cnt_eq_zero <= 1'b1;
pkt_cnt_eq_one <= 1'b0;
fifo_fill_level_lt_cut_through_threshold <= 1'b1;
end
else begin
fifo_fill_level_lt_cut_through_threshold <= fifo_fill_level < cut_through_threshold;
fifo_too_small_r <= fifo_too_small;
if( in_pkt_eop_arrive )
sop_has_left_fifo <= 1'b0;
else if (out_pkt_sop_leave & pkt_cnt_eq_zero )
sop_has_left_fifo <= 1'b1;
if (in_pkt_eop_arrive & ~out_pkt_leave & ~drop_on_error ) begin
pkt_cnt <= pkt_cnt + 1'b1;
pkt_cnt_eq_zero <= 0;
if (pkt_cnt == 0)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
else if((~in_pkt_eop_arrive | drop_on_error) & out_pkt_leave) begin
pkt_cnt <= pkt_cnt - 1'b1;
if (pkt_cnt == 1)
pkt_cnt_eq_zero <= 1'b1;
else
pkt_cnt_eq_zero <= 1'b0;
if (pkt_cnt == 2)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
if (in_pkt_start)
pkt_has_started <= 1'b1;
else if (in_pkt_eop_arrive)
pkt_has_started <= 1'b0;
end
end
// drop on error logic
always @(posedge clk or posedge reset) begin
if (reset) begin
sop_ptr <= 0;
error_in_pkt <= 0;
end
else begin
// save the location of the SOP
if ( in_pkt_start )
sop_ptr <= wr_ptr;
// remember if error in pkt
// log error only if packet has already started
if (in_pkt_eop_arrive)
error_in_pkt <= 1'b0;
else if ( in_pkt_error & (pkt_has_started | in_pkt_start))
error_in_pkt <= 1'b1;
end
end
assign drop_on_error = drop_on_error_en & (error_in_pkt | in_pkt_error) & in_pkt_eop_arrive &
~sop_has_left_fifo & ~(out_pkt_sop_leave & pkt_cnt_eq_zero);
assign curr_sop_ptr = (write && in_startofpacket && in_endofpacket) ? wr_ptr : sop_ptr;
end
else begin : gen_blk20_else
assign ok_to_forward = 1'b1;
assign drop_on_error = 1'b0;
if (ADDR_WIDTH <= 1)
assign curr_sop_ptr = 1'b0;
else
assign curr_sop_ptr = {ADDR_WIDTH - 1 { 1'b0 }};
end
endgenerate
// --------------------------------------------------
// Calculates the log2ceil of the input value
// --------------------------------------------------
function integer log2ceil;
input integer val;
reg[31:0] i;
begin
i = 1;
log2ceil = 0;
while (i < val) begin
log2ceil = log2ceil + 1;
i = i[30:0] << 1;
end
end
endfunction
endmodule |
module altera_avalon_sc_fifo
#(
// --------------------------------------------------
// Parameters
// --------------------------------------------------
parameter SYMBOLS_PER_BEAT = 1,
parameter BITS_PER_SYMBOL = 8,
parameter FIFO_DEPTH = 16,
parameter CHANNEL_WIDTH = 0,
parameter ERROR_WIDTH = 0,
parameter USE_PACKETS = 0,
parameter USE_FILL_LEVEL = 0,
parameter USE_STORE_FORWARD = 0,
parameter USE_ALMOST_FULL_IF = 0,
parameter USE_ALMOST_EMPTY_IF = 0,
// --------------------------------------------------
// Empty latency is defined as the number of cycles
// required for a write to deassert the empty flag.
// For example, a latency of 1 means that the empty
// flag is deasserted on the cycle after a write.
//
// Another way to think of it is the latency for a
// write to propagate to the output.
//
// An empty latency of 0 implies lookahead, which is
// only implemented for the register-based FIFO.
// --------------------------------------------------
parameter EMPTY_LATENCY = 3,
parameter USE_MEMORY_BLOCKS = 1,
// --------------------------------------------------
// Internal Parameters
// --------------------------------------------------
parameter DATA_WIDTH = SYMBOLS_PER_BEAT * BITS_PER_SYMBOL,
parameter EMPTY_WIDTH = log2ceil(SYMBOLS_PER_BEAT)
)
(
// --------------------------------------------------
// Ports
// --------------------------------------------------
input clk,
input reset,
input [DATA_WIDTH-1: 0] in_data,
input in_valid,
input in_startofpacket,
input in_endofpacket,
input [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] in_empty,
input [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] in_error,
input [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] in_channel,
output in_ready,
output [DATA_WIDTH-1 : 0] out_data,
output reg out_valid,
output out_startofpacket,
output out_endofpacket,
output [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] out_empty,
output [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] out_error,
output [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] out_channel,
input out_ready,
input [(USE_STORE_FORWARD ? 2 : 1) : 0] csr_address,
input csr_write,
input csr_read,
input [31 : 0] csr_writedata,
output reg [31 : 0] csr_readdata,
output wire almost_full_data,
output wire almost_empty_data
);
// --------------------------------------------------
// Local Parameters
// --------------------------------------------------
localparam ADDR_WIDTH = log2ceil(FIFO_DEPTH);
localparam DEPTH = FIFO_DEPTH;
localparam PKT_SIGNALS_WIDTH = 2 + EMPTY_WIDTH;
localparam PAYLOAD_WIDTH = (USE_PACKETS == 1) ?
2 + EMPTY_WIDTH + DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH:
DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH;
// --------------------------------------------------
// Internal Signals
// --------------------------------------------------
genvar i;
reg [PAYLOAD_WIDTH-1 : 0] mem [DEPTH-1 : 0];
reg [ADDR_WIDTH-1 : 0] wr_ptr;
reg [ADDR_WIDTH-1 : 0] rd_ptr;
reg [DEPTH-1 : 0] mem_used;
wire [ADDR_WIDTH-1 : 0] next_wr_ptr;
wire [ADDR_WIDTH-1 : 0] next_rd_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_wr_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_rd_ptr;
wire [ADDR_WIDTH-1 : 0] mem_rd_ptr;
wire read;
wire write;
reg empty;
reg next_empty;
reg full;
reg next_full;
wire [PKT_SIGNALS_WIDTH-1 : 0] in_packet_signals;
wire [PKT_SIGNALS_WIDTH-1 : 0] out_packet_signals;
wire [PAYLOAD_WIDTH-1 : 0] in_payload;
reg [PAYLOAD_WIDTH-1 : 0] internal_out_payload;
reg [PAYLOAD_WIDTH-1 : 0] out_payload;
reg internal_out_valid;
wire internal_out_ready;
reg [ADDR_WIDTH : 0] fifo_fill_level;
reg [ADDR_WIDTH : 0] fill_level;
reg [ADDR_WIDTH-1 : 0] sop_ptr = 0;
wire [ADDR_WIDTH-1 : 0] curr_sop_ptr;
reg [23:0] almost_full_threshold;
reg [23:0] almost_empty_threshold;
reg [23:0] cut_through_threshold;
reg [15:0] pkt_cnt;
reg drop_on_error_en;
reg error_in_pkt;
reg pkt_has_started;
reg sop_has_left_fifo;
reg fifo_too_small_r;
reg pkt_cnt_eq_zero;
reg pkt_cnt_eq_one;
wire wait_for_threshold;
reg pkt_mode;
wire wait_for_pkt;
wire ok_to_forward;
wire in_pkt_eop_arrive;
wire out_pkt_leave;
wire in_pkt_start;
wire in_pkt_error;
wire drop_on_error;
wire fifo_too_small;
wire out_pkt_sop_leave;
wire [31:0] max_fifo_size;
reg fifo_fill_level_lt_cut_through_threshold;
// --------------------------------------------------
// Define Payload
//
// Icky part where we decide which signals form the
// payload to the FIFO with generate blocks.
// --------------------------------------------------
generate
if (EMPTY_WIDTH > 0) begin : gen_blk1
assign in_packet_signals = {in_startofpacket, in_endofpacket, in_empty};
assign {out_startofpacket, out_endofpacket, out_empty} = out_packet_signals;
end
else begin : gen_blk1_else
assign out_empty = in_error;
assign in_packet_signals = {in_startofpacket, in_endofpacket};
assign {out_startofpacket, out_endofpacket} = out_packet_signals;
end
endgenerate
generate
if (USE_PACKETS) begin : gen_blk2
if (ERROR_WIDTH > 0) begin : gen_blk3
if (CHANNEL_WIDTH > 0) begin : gen_blk4
assign in_payload = {in_packet_signals, in_data, in_error, in_channel};
assign {out_packet_signals, out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk4_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data, in_error};
assign {out_packet_signals, out_data, out_error} = out_payload;
end
end
else begin : gen_blk3_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk5
assign in_payload = {in_packet_signals, in_data, in_channel};
assign {out_packet_signals, out_data, out_channel} = out_payload;
end
else begin : gen_blk5_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data};
assign {out_packet_signals, out_data} = out_payload;
end
end
end
else begin : gen_blk2_else
assign out_packet_signals = 0;
if (ERROR_WIDTH > 0) begin : gen_blk6
if (CHANNEL_WIDTH > 0) begin : gen_blk7
assign in_payload = {in_data, in_error, in_channel};
assign {out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk7_else
assign out_channel = in_channel;
assign in_payload = {in_data, in_error};
assign {out_data, out_error} = out_payload;
end
end
else begin : gen_blk6_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk8
assign in_payload = {in_data, in_channel};
assign {out_data, out_channel} = out_payload;
end
else begin : gen_blk8_else
assign out_channel = in_channel;
assign in_payload = in_data;
assign out_data = out_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Memory-based FIFO storage
//
// To allow a ready latency of 0, the read index is
// obtained from the next read pointer and memory
// outputs are unregistered.
//
// If the empty latency is 1, we infer bypass logic
// around the memory so writes propagate to the
// outputs on the next cycle.
//
// Do not change the way this is coded: Quartus needs
// a perfect match to the template, and any attempt to
// refactor the two always blocks into one will break
// memory inference.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk9
if (EMPTY_LATENCY == 1) begin : gen_blk10
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] = in_payload;
internal_out_payload = mem[mem_rd_ptr];
end
end else begin : gen_blk10_else
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] <= in_payload;
internal_out_payload <= mem[mem_rd_ptr];
end
end
assign mem_rd_ptr = next_rd_ptr;
end else begin : gen_blk9_else
// --------------------------------------------------
// Register-based FIFO storage
//
// Uses a shift register as the storage element. Each
// shift register slot has a bit which indicates if
// the slot is occupied (credit to Sam H for the idea).
// The occupancy bits are contiguous and start from the
// lsb, so 0000, 0001, 0011, 0111, 1111 for a 4-deep
// FIFO.
//
// Each slot is enabled during a read or when it
// is unoccupied. New data is always written to every
// going-to-be-empty slot (we keep track of which ones
// are actually useful with the occupancy bits). On a
// read we shift occupied slots.
//
// The exception is the last slot, which always gets
// new data when it is unoccupied.
// --------------------------------------------------
for (i = 0; i < DEPTH-1; i = i + 1) begin : shift_reg
always @(posedge clk or posedge reset) begin
if (reset) begin
mem[i] <= 0;
end
else if (read || !mem_used[i]) begin
if (!mem_used[i+1])
mem[i] <= in_payload;
else
mem[i] <= mem[i+1];
end
end
end
always @(posedge clk, posedge reset) begin
if (reset) begin
mem[DEPTH-1] <= 0;
end
else begin
if (DEPTH == 1) begin
if (write)
mem[DEPTH-1] <= in_payload;
end
else if (!mem_used[DEPTH-1])
mem[DEPTH-1] <= in_payload;
end
end
end
endgenerate
assign read = internal_out_ready && internal_out_valid && ok_to_forward;
assign write = in_ready && in_valid;
// --------------------------------------------------
// Pointer Management
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk11
assign incremented_wr_ptr = wr_ptr + 1'b1;
assign incremented_rd_ptr = rd_ptr + 1'b1;
assign next_wr_ptr = drop_on_error ? curr_sop_ptr : write ? incremented_wr_ptr : wr_ptr;
assign next_rd_ptr = (read) ? incremented_rd_ptr : rd_ptr;
always @(posedge clk or posedge reset) begin
if (reset) begin
wr_ptr <= 0;
rd_ptr <= 0;
end
else begin
wr_ptr <= next_wr_ptr;
rd_ptr <= next_rd_ptr;
end
end
end else begin : gen_blk11_else
// --------------------------------------------------
// Shift Register Occupancy Bits
//
// Consider a 4-deep FIFO with 2 entries: 0011
// On a read and write, do not modify the bits.
// On a write, left-shift the bits to get 0111.
// On a read, right-shift the bits to get 0001.
//
// Also, on a write we set bit0 (the head), while
// clearing the tail on a read.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[0] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[0] <= 1;
else if (read) begin
if (DEPTH > 1)
mem_used[0] <= mem_used[1];
else
mem_used[0] <= 0;
end
end
end
end
if (DEPTH > 1) begin : gen_blk12
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[DEPTH-1] <= 0;
end
else begin
if (write ^ read) begin
mem_used[DEPTH-1] <= 0;
if (write)
mem_used[DEPTH-1] <= mem_used[DEPTH-2];
end
end
end
end
for (i = 1; i < DEPTH-1; i = i + 1) begin : storage_logic
always @(posedge clk, posedge reset) begin
if (reset) begin
mem_used[i] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[i] <= mem_used[i-1];
else if (read)
mem_used[i] <= mem_used[i+1];
end
end
end
end
end
endgenerate
// --------------------------------------------------
// Memory FIFO Status Management
//
// Generates the full and empty signals from the
// pointers. The FIFO is full when the next write
// pointer will be equal to the read pointer after
// a write. Reading from a FIFO clears full.
//
// The FIFO is empty when the next read pointer will
// be equal to the write pointer after a read. Writing
// to a FIFO clears empty.
//
// A simultaneous read and write must not change any of
// the empty or full flags unless there is a drop on error event.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk13
always @* begin
next_full = full;
next_empty = empty;
if (read && !write) begin
next_full = 1'b0;
if (incremented_rd_ptr == wr_ptr)
next_empty = 1'b1;
end
if (write && !read) begin
if (!drop_on_error)
next_empty = 1'b0;
else if (curr_sop_ptr == rd_ptr) // drop on error and only 1 pkt in fifo
next_empty = 1'b1;
if (incremented_wr_ptr == rd_ptr && !drop_on_error)
next_full = 1'b1;
end
if (write && read && drop_on_error) begin
if (curr_sop_ptr == next_rd_ptr)
next_empty = 1'b1;
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
empty <= 1;
full <= 0;
end
else begin
empty <= next_empty;
full <= next_full;
end
end
end else begin : gen_blk13_else
// --------------------------------------------------
// Register FIFO Status Management
//
// Full when the tail occupancy bit is 1. Empty when
// the head occupancy bit is 0.
// --------------------------------------------------
always @* begin
full = mem_used[DEPTH-1];
empty = !mem_used[0];
// ------------------------------------------
// For a single slot FIFO, reading clears the
// full status immediately.
// ------------------------------------------
if (DEPTH == 1)
full = mem_used[0] && !read;
internal_out_payload = mem[0];
// ------------------------------------------
// Writes clear empty immediately for lookahead modes.
// Note that we use in_valid instead of write to avoid
// combinational loops (in lookahead mode, qualifying
// with in_ready is meaningless).
//
// In a 1-deep FIFO, a possible combinational loop runs
// from write -> out_valid -> out_ready -> write
// ------------------------------------------
if (EMPTY_LATENCY == 0) begin
empty = !mem_used[0] && !in_valid;
if (!mem_used[0] && in_valid)
internal_out_payload = in_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Avalon-ST Signals
//
// The in_ready signal is straightforward.
//
// To match memory latency when empty latency > 1,
// out_valid assertions must be delayed by one clock
// cycle.
//
// Note: out_valid deassertions must not be delayed or
// the FIFO will underflow.
// --------------------------------------------------
assign in_ready = !full;
assign internal_out_ready = out_ready || !out_valid;
generate if (EMPTY_LATENCY > 1) begin : gen_blk14
always @(posedge clk or posedge reset) begin
if (reset)
internal_out_valid <= 0;
else begin
internal_out_valid <= !empty & ok_to_forward & ~drop_on_error;
if (read) begin
if (incremented_rd_ptr == wr_ptr)
internal_out_valid <= 1'b0;
end
end
end
end else begin : gen_blk14_else
always @* begin
internal_out_valid = !empty & ok_to_forward;
end
end
endgenerate
// --------------------------------------------------
// Single Output Pipeline Stage
//
// This output pipeline stage is enabled if the FIFO's
// empty latency is set to 3 (default). It is disabled
// for all other allowed latencies.
//
// Reason: The memory outputs are unregistered, so we have to
// register the output or fmax will drop if combinatorial
// logic is present on the output datapath.
//
// Q: The Avalon-ST spec says that I have to register my outputs
// But isn't the memory counted as a register?
// A: The path from the address lookup to the memory output is
// slow. Registering the memory outputs is a good idea.
//
// The registers get packed into the memory by the fitter
// which means minimal resources are consumed (the result
// is a altsyncram with registered outputs, available on
// all modern Altera devices).
//
// This output stage acts as an extra slot in the FIFO,
// and complicates the fill level.
// --------------------------------------------------
generate if (EMPTY_LATENCY == 3) begin : gen_blk15
always @(posedge clk or posedge reset) begin
if (reset) begin
out_valid <= 0;
out_payload <= 0;
end
else begin
if (internal_out_ready) begin
out_valid <= internal_out_valid & ok_to_forward;
out_payload <= internal_out_payload;
end
end
end
end
else begin : gen_blk15_else
always @* begin
out_valid = internal_out_valid;
out_payload = internal_out_payload;
end
end
endgenerate
// --------------------------------------------------
// Fill Level
//
// The fill level is calculated from the next write
// and read pointers to avoid unnecessary latency
// and logic.
//
// However, if the store-and-forward mode of the FIFO
// is enabled, the fill level is an up-down counter
// for fmax optimization reasons.
//
// If the output pipeline is enabled, the fill level
// must account for it, or we'll always be off by one.
// This may, or may not be important depending on the
// application.
//
// For now, we'll always calculate the exact fill level
// at the cost of an extra adder when the output stage
// is enabled.
// --------------------------------------------------
generate if (USE_FILL_LEVEL) begin : gen_blk16
wire [31:0] depth32;
assign depth32 = DEPTH;
if (USE_STORE_FORWARD) begin
reg [ADDR_WIDTH : 0] curr_packet_len_less_one;
// --------------------------------------------------
// We only drop on endofpacket. As long as we don't add to the fill
// level on the dropped endofpacket cycle, we can simply subtract
// (packet length - 1) from the fill level for dropped packets.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
curr_packet_len_less_one <= 0;
end else begin
if (write) begin
curr_packet_len_less_one <= curr_packet_len_less_one + 1'b1;
if (in_endofpacket)
curr_packet_len_less_one <= 0;
end
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
fifo_fill_level <= 0;
end else if (drop_on_error) begin
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one;
if (read)
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one - 1'b1;
end else if (write && !read) begin
fifo_fill_level <= fifo_fill_level + 1'b1;
end else if (read && !write) begin
fifo_fill_level <= fifo_fill_level - 1'b1;
end
end
end else begin
always @(posedge clk or posedge reset) begin
if (reset)
fifo_fill_level <= 0;
else if (next_full & !drop_on_error)
fifo_fill_level <= depth32[ADDR_WIDTH:0];
else begin
fifo_fill_level[ADDR_WIDTH] <= 1'b0;
fifo_fill_level[ADDR_WIDTH-1 : 0] <= next_wr_ptr - next_rd_ptr;
end
end
end
always @* begin
fill_level = fifo_fill_level;
if (EMPTY_LATENCY == 3)
fill_level = fifo_fill_level + {{ADDR_WIDTH{1'b0}}, out_valid};
end
end
else begin : gen_blk16_else
always @* begin
fill_level = 0;
end
end
endgenerate
generate if (USE_ALMOST_FULL_IF) begin : gen_blk17
assign almost_full_data = (fill_level >= almost_full_threshold);
end
else
assign almost_full_data = 0;
endgenerate
generate if (USE_ALMOST_EMPTY_IF) begin : gen_blk18
assign almost_empty_data = (fill_level <= almost_empty_threshold);
end
else
assign almost_empty_data = 0;
endgenerate
// --------------------------------------------------
// Avalon-MM Status & Control Connection Point
//
// Register map:
//
// | Addr | RW | 31 - 0 |
// | 0 | R | Fill level |
//
// The registering of this connection point means
// that there is a cycle of latency between
// reads/writes and the updating of the fill level.
// --------------------------------------------------
generate if (USE_STORE_FORWARD) begin : gen_blk19
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
cut_through_threshold <= 0;
drop_on_error_en <= 0;
csr_readdata <= 0;
pkt_mode <= 1'b1;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 5)
csr_readdata <= {31'b0, drop_on_error_en};
else if (csr_address == 4)
csr_readdata <= {8'b0, cut_through_threshold};
else if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b101)
drop_on_error_en <= csr_writedata[0];
else if(csr_address == 3'b100) begin
cut_through_threshold <= csr_writedata[23:0];
pkt_mode <= (csr_writedata[23:0] == 0);
end
else if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else if (USE_ALMOST_FULL_IF || USE_ALMOST_EMPTY_IF) begin : gen_blk19_else1
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
csr_readdata <= 0;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else begin : gen_blk19_else2
always @(posedge clk or posedge reset) begin
if (reset) begin
csr_readdata <= 0;
end
else if (csr_read) begin
csr_readdata <= 0;
if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
end
end
endgenerate
// --------------------------------------------------
// Store and forward logic
// --------------------------------------------------
// if the fifo gets full before the entire packet or the
// cut-threshold condition is met then start sending out
// data in order to avoid dead-lock situation
generate if (USE_STORE_FORWARD) begin : gen_blk20
assign wait_for_threshold = (fifo_fill_level_lt_cut_through_threshold) & wait_for_pkt ;
assign wait_for_pkt = pkt_cnt_eq_zero | (pkt_cnt_eq_one & out_pkt_leave);
assign ok_to_forward = (pkt_mode ? (~wait_for_pkt | ~pkt_has_started) :
~wait_for_threshold) | fifo_too_small_r;
assign in_pkt_eop_arrive = in_valid & in_ready & in_endofpacket;
assign in_pkt_start = in_valid & in_ready & in_startofpacket;
assign in_pkt_error = in_valid & in_ready & |in_error;
assign out_pkt_sop_leave = out_valid & out_ready & out_startofpacket;
assign out_pkt_leave = out_valid & out_ready & out_endofpacket;
assign fifo_too_small = (pkt_mode ? wait_for_pkt : wait_for_threshold) & full & out_ready;
// count packets coming and going into the fifo
always @(posedge clk or posedge reset) begin
if (reset) begin
pkt_cnt <= 0;
pkt_has_started <= 0;
sop_has_left_fifo <= 0;
fifo_too_small_r <= 0;
pkt_cnt_eq_zero <= 1'b1;
pkt_cnt_eq_one <= 1'b0;
fifo_fill_level_lt_cut_through_threshold <= 1'b1;
end
else begin
fifo_fill_level_lt_cut_through_threshold <= fifo_fill_level < cut_through_threshold;
fifo_too_small_r <= fifo_too_small;
if( in_pkt_eop_arrive )
sop_has_left_fifo <= 1'b0;
else if (out_pkt_sop_leave & pkt_cnt_eq_zero )
sop_has_left_fifo <= 1'b1;
if (in_pkt_eop_arrive & ~out_pkt_leave & ~drop_on_error ) begin
pkt_cnt <= pkt_cnt + 1'b1;
pkt_cnt_eq_zero <= 0;
if (pkt_cnt == 0)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
else if((~in_pkt_eop_arrive | drop_on_error) & out_pkt_leave) begin
pkt_cnt <= pkt_cnt - 1'b1;
if (pkt_cnt == 1)
pkt_cnt_eq_zero <= 1'b1;
else
pkt_cnt_eq_zero <= 1'b0;
if (pkt_cnt == 2)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
if (in_pkt_start)
pkt_has_started <= 1'b1;
else if (in_pkt_eop_arrive)
pkt_has_started <= 1'b0;
end
end
// drop on error logic
always @(posedge clk or posedge reset) begin
if (reset) begin
sop_ptr <= 0;
error_in_pkt <= 0;
end
else begin
// save the location of the SOP
if ( in_pkt_start )
sop_ptr <= wr_ptr;
// remember if error in pkt
// log error only if packet has already started
if (in_pkt_eop_arrive)
error_in_pkt <= 1'b0;
else if ( in_pkt_error & (pkt_has_started | in_pkt_start))
error_in_pkt <= 1'b1;
end
end
assign drop_on_error = drop_on_error_en & (error_in_pkt | in_pkt_error) & in_pkt_eop_arrive &
~sop_has_left_fifo & ~(out_pkt_sop_leave & pkt_cnt_eq_zero);
assign curr_sop_ptr = (write && in_startofpacket && in_endofpacket) ? wr_ptr : sop_ptr;
end
else begin : gen_blk20_else
assign ok_to_forward = 1'b1;
assign drop_on_error = 1'b0;
if (ADDR_WIDTH <= 1)
assign curr_sop_ptr = 1'b0;
else
assign curr_sop_ptr = {ADDR_WIDTH - 1 { 1'b0 }};
end
endgenerate
// --------------------------------------------------
// Calculates the log2ceil of the input value
// --------------------------------------------------
function integer log2ceil;
input integer val;
reg[31:0] i;
begin
i = 1;
log2ceil = 0;
while (i < val) begin
log2ceil = log2ceil + 1;
i = i[30:0] << 1;
end
end
endfunction
endmodule |
module altera_avalon_sc_fifo
#(
// --------------------------------------------------
// Parameters
// --------------------------------------------------
parameter SYMBOLS_PER_BEAT = 1,
parameter BITS_PER_SYMBOL = 8,
parameter FIFO_DEPTH = 16,
parameter CHANNEL_WIDTH = 0,
parameter ERROR_WIDTH = 0,
parameter USE_PACKETS = 0,
parameter USE_FILL_LEVEL = 0,
parameter USE_STORE_FORWARD = 0,
parameter USE_ALMOST_FULL_IF = 0,
parameter USE_ALMOST_EMPTY_IF = 0,
// --------------------------------------------------
// Empty latency is defined as the number of cycles
// required for a write to deassert the empty flag.
// For example, a latency of 1 means that the empty
// flag is deasserted on the cycle after a write.
//
// Another way to think of it is the latency for a
// write to propagate to the output.
//
// An empty latency of 0 implies lookahead, which is
// only implemented for the register-based FIFO.
// --------------------------------------------------
parameter EMPTY_LATENCY = 3,
parameter USE_MEMORY_BLOCKS = 1,
// --------------------------------------------------
// Internal Parameters
// --------------------------------------------------
parameter DATA_WIDTH = SYMBOLS_PER_BEAT * BITS_PER_SYMBOL,
parameter EMPTY_WIDTH = log2ceil(SYMBOLS_PER_BEAT)
)
(
// --------------------------------------------------
// Ports
// --------------------------------------------------
input clk,
input reset,
input [DATA_WIDTH-1: 0] in_data,
input in_valid,
input in_startofpacket,
input in_endofpacket,
input [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] in_empty,
input [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] in_error,
input [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] in_channel,
output in_ready,
output [DATA_WIDTH-1 : 0] out_data,
output reg out_valid,
output out_startofpacket,
output out_endofpacket,
output [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] out_empty,
output [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] out_error,
output [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] out_channel,
input out_ready,
input [(USE_STORE_FORWARD ? 2 : 1) : 0] csr_address,
input csr_write,
input csr_read,
input [31 : 0] csr_writedata,
output reg [31 : 0] csr_readdata,
output wire almost_full_data,
output wire almost_empty_data
);
// --------------------------------------------------
// Local Parameters
// --------------------------------------------------
localparam ADDR_WIDTH = log2ceil(FIFO_DEPTH);
localparam DEPTH = FIFO_DEPTH;
localparam PKT_SIGNALS_WIDTH = 2 + EMPTY_WIDTH;
localparam PAYLOAD_WIDTH = (USE_PACKETS == 1) ?
2 + EMPTY_WIDTH + DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH:
DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH;
// --------------------------------------------------
// Internal Signals
// --------------------------------------------------
genvar i;
reg [PAYLOAD_WIDTH-1 : 0] mem [DEPTH-1 : 0];
reg [ADDR_WIDTH-1 : 0] wr_ptr;
reg [ADDR_WIDTH-1 : 0] rd_ptr;
reg [DEPTH-1 : 0] mem_used;
wire [ADDR_WIDTH-1 : 0] next_wr_ptr;
wire [ADDR_WIDTH-1 : 0] next_rd_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_wr_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_rd_ptr;
wire [ADDR_WIDTH-1 : 0] mem_rd_ptr;
wire read;
wire write;
reg empty;
reg next_empty;
reg full;
reg next_full;
wire [PKT_SIGNALS_WIDTH-1 : 0] in_packet_signals;
wire [PKT_SIGNALS_WIDTH-1 : 0] out_packet_signals;
wire [PAYLOAD_WIDTH-1 : 0] in_payload;
reg [PAYLOAD_WIDTH-1 : 0] internal_out_payload;
reg [PAYLOAD_WIDTH-1 : 0] out_payload;
reg internal_out_valid;
wire internal_out_ready;
reg [ADDR_WIDTH : 0] fifo_fill_level;
reg [ADDR_WIDTH : 0] fill_level;
reg [ADDR_WIDTH-1 : 0] sop_ptr = 0;
wire [ADDR_WIDTH-1 : 0] curr_sop_ptr;
reg [23:0] almost_full_threshold;
reg [23:0] almost_empty_threshold;
reg [23:0] cut_through_threshold;
reg [15:0] pkt_cnt;
reg drop_on_error_en;
reg error_in_pkt;
reg pkt_has_started;
reg sop_has_left_fifo;
reg fifo_too_small_r;
reg pkt_cnt_eq_zero;
reg pkt_cnt_eq_one;
wire wait_for_threshold;
reg pkt_mode;
wire wait_for_pkt;
wire ok_to_forward;
wire in_pkt_eop_arrive;
wire out_pkt_leave;
wire in_pkt_start;
wire in_pkt_error;
wire drop_on_error;
wire fifo_too_small;
wire out_pkt_sop_leave;
wire [31:0] max_fifo_size;
reg fifo_fill_level_lt_cut_through_threshold;
// --------------------------------------------------
// Define Payload
//
// Icky part where we decide which signals form the
// payload to the FIFO with generate blocks.
// --------------------------------------------------
generate
if (EMPTY_WIDTH > 0) begin : gen_blk1
assign in_packet_signals = {in_startofpacket, in_endofpacket, in_empty};
assign {out_startofpacket, out_endofpacket, out_empty} = out_packet_signals;
end
else begin : gen_blk1_else
assign out_empty = in_error;
assign in_packet_signals = {in_startofpacket, in_endofpacket};
assign {out_startofpacket, out_endofpacket} = out_packet_signals;
end
endgenerate
generate
if (USE_PACKETS) begin : gen_blk2
if (ERROR_WIDTH > 0) begin : gen_blk3
if (CHANNEL_WIDTH > 0) begin : gen_blk4
assign in_payload = {in_packet_signals, in_data, in_error, in_channel};
assign {out_packet_signals, out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk4_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data, in_error};
assign {out_packet_signals, out_data, out_error} = out_payload;
end
end
else begin : gen_blk3_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk5
assign in_payload = {in_packet_signals, in_data, in_channel};
assign {out_packet_signals, out_data, out_channel} = out_payload;
end
else begin : gen_blk5_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data};
assign {out_packet_signals, out_data} = out_payload;
end
end
end
else begin : gen_blk2_else
assign out_packet_signals = 0;
if (ERROR_WIDTH > 0) begin : gen_blk6
if (CHANNEL_WIDTH > 0) begin : gen_blk7
assign in_payload = {in_data, in_error, in_channel};
assign {out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk7_else
assign out_channel = in_channel;
assign in_payload = {in_data, in_error};
assign {out_data, out_error} = out_payload;
end
end
else begin : gen_blk6_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk8
assign in_payload = {in_data, in_channel};
assign {out_data, out_channel} = out_payload;
end
else begin : gen_blk8_else
assign out_channel = in_channel;
assign in_payload = in_data;
assign out_data = out_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Memory-based FIFO storage
//
// To allow a ready latency of 0, the read index is
// obtained from the next read pointer and memory
// outputs are unregistered.
//
// If the empty latency is 1, we infer bypass logic
// around the memory so writes propagate to the
// outputs on the next cycle.
//
// Do not change the way this is coded: Quartus needs
// a perfect match to the template, and any attempt to
// refactor the two always blocks into one will break
// memory inference.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk9
if (EMPTY_LATENCY == 1) begin : gen_blk10
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] = in_payload;
internal_out_payload = mem[mem_rd_ptr];
end
end else begin : gen_blk10_else
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] <= in_payload;
internal_out_payload <= mem[mem_rd_ptr];
end
end
assign mem_rd_ptr = next_rd_ptr;
end else begin : gen_blk9_else
// --------------------------------------------------
// Register-based FIFO storage
//
// Uses a shift register as the storage element. Each
// shift register slot has a bit which indicates if
// the slot is occupied (credit to Sam H for the idea).
// The occupancy bits are contiguous and start from the
// lsb, so 0000, 0001, 0011, 0111, 1111 for a 4-deep
// FIFO.
//
// Each slot is enabled during a read or when it
// is unoccupied. New data is always written to every
// going-to-be-empty slot (we keep track of which ones
// are actually useful with the occupancy bits). On a
// read we shift occupied slots.
//
// The exception is the last slot, which always gets
// new data when it is unoccupied.
// --------------------------------------------------
for (i = 0; i < DEPTH-1; i = i + 1) begin : shift_reg
always @(posedge clk or posedge reset) begin
if (reset) begin
mem[i] <= 0;
end
else if (read || !mem_used[i]) begin
if (!mem_used[i+1])
mem[i] <= in_payload;
else
mem[i] <= mem[i+1];
end
end
end
always @(posedge clk, posedge reset) begin
if (reset) begin
mem[DEPTH-1] <= 0;
end
else begin
if (DEPTH == 1) begin
if (write)
mem[DEPTH-1] <= in_payload;
end
else if (!mem_used[DEPTH-1])
mem[DEPTH-1] <= in_payload;
end
end
end
endgenerate
assign read = internal_out_ready && internal_out_valid && ok_to_forward;
assign write = in_ready && in_valid;
// --------------------------------------------------
// Pointer Management
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk11
assign incremented_wr_ptr = wr_ptr + 1'b1;
assign incremented_rd_ptr = rd_ptr + 1'b1;
assign next_wr_ptr = drop_on_error ? curr_sop_ptr : write ? incremented_wr_ptr : wr_ptr;
assign next_rd_ptr = (read) ? incremented_rd_ptr : rd_ptr;
always @(posedge clk or posedge reset) begin
if (reset) begin
wr_ptr <= 0;
rd_ptr <= 0;
end
else begin
wr_ptr <= next_wr_ptr;
rd_ptr <= next_rd_ptr;
end
end
end else begin : gen_blk11_else
// --------------------------------------------------
// Shift Register Occupancy Bits
//
// Consider a 4-deep FIFO with 2 entries: 0011
// On a read and write, do not modify the bits.
// On a write, left-shift the bits to get 0111.
// On a read, right-shift the bits to get 0001.
//
// Also, on a write we set bit0 (the head), while
// clearing the tail on a read.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[0] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[0] <= 1;
else if (read) begin
if (DEPTH > 1)
mem_used[0] <= mem_used[1];
else
mem_used[0] <= 0;
end
end
end
end
if (DEPTH > 1) begin : gen_blk12
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[DEPTH-1] <= 0;
end
else begin
if (write ^ read) begin
mem_used[DEPTH-1] <= 0;
if (write)
mem_used[DEPTH-1] <= mem_used[DEPTH-2];
end
end
end
end
for (i = 1; i < DEPTH-1; i = i + 1) begin : storage_logic
always @(posedge clk, posedge reset) begin
if (reset) begin
mem_used[i] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[i] <= mem_used[i-1];
else if (read)
mem_used[i] <= mem_used[i+1];
end
end
end
end
end
endgenerate
// --------------------------------------------------
// Memory FIFO Status Management
//
// Generates the full and empty signals from the
// pointers. The FIFO is full when the next write
// pointer will be equal to the read pointer after
// a write. Reading from a FIFO clears full.
//
// The FIFO is empty when the next read pointer will
// be equal to the write pointer after a read. Writing
// to a FIFO clears empty.
//
// A simultaneous read and write must not change any of
// the empty or full flags unless there is a drop on error event.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk13
always @* begin
next_full = full;
next_empty = empty;
if (read && !write) begin
next_full = 1'b0;
if (incremented_rd_ptr == wr_ptr)
next_empty = 1'b1;
end
if (write && !read) begin
if (!drop_on_error)
next_empty = 1'b0;
else if (curr_sop_ptr == rd_ptr) // drop on error and only 1 pkt in fifo
next_empty = 1'b1;
if (incremented_wr_ptr == rd_ptr && !drop_on_error)
next_full = 1'b1;
end
if (write && read && drop_on_error) begin
if (curr_sop_ptr == next_rd_ptr)
next_empty = 1'b1;
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
empty <= 1;
full <= 0;
end
else begin
empty <= next_empty;
full <= next_full;
end
end
end else begin : gen_blk13_else
// --------------------------------------------------
// Register FIFO Status Management
//
// Full when the tail occupancy bit is 1. Empty when
// the head occupancy bit is 0.
// --------------------------------------------------
always @* begin
full = mem_used[DEPTH-1];
empty = !mem_used[0];
// ------------------------------------------
// For a single slot FIFO, reading clears the
// full status immediately.
// ------------------------------------------
if (DEPTH == 1)
full = mem_used[0] && !read;
internal_out_payload = mem[0];
// ------------------------------------------
// Writes clear empty immediately for lookahead modes.
// Note that we use in_valid instead of write to avoid
// combinational loops (in lookahead mode, qualifying
// with in_ready is meaningless).
//
// In a 1-deep FIFO, a possible combinational loop runs
// from write -> out_valid -> out_ready -> write
// ------------------------------------------
if (EMPTY_LATENCY == 0) begin
empty = !mem_used[0] && !in_valid;
if (!mem_used[0] && in_valid)
internal_out_payload = in_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Avalon-ST Signals
//
// The in_ready signal is straightforward.
//
// To match memory latency when empty latency > 1,
// out_valid assertions must be delayed by one clock
// cycle.
//
// Note: out_valid deassertions must not be delayed or
// the FIFO will underflow.
// --------------------------------------------------
assign in_ready = !full;
assign internal_out_ready = out_ready || !out_valid;
generate if (EMPTY_LATENCY > 1) begin : gen_blk14
always @(posedge clk or posedge reset) begin
if (reset)
internal_out_valid <= 0;
else begin
internal_out_valid <= !empty & ok_to_forward & ~drop_on_error;
if (read) begin
if (incremented_rd_ptr == wr_ptr)
internal_out_valid <= 1'b0;
end
end
end
end else begin : gen_blk14_else
always @* begin
internal_out_valid = !empty & ok_to_forward;
end
end
endgenerate
// --------------------------------------------------
// Single Output Pipeline Stage
//
// This output pipeline stage is enabled if the FIFO's
// empty latency is set to 3 (default). It is disabled
// for all other allowed latencies.
//
// Reason: The memory outputs are unregistered, so we have to
// register the output or fmax will drop if combinatorial
// logic is present on the output datapath.
//
// Q: The Avalon-ST spec says that I have to register my outputs
// But isn't the memory counted as a register?
// A: The path from the address lookup to the memory output is
// slow. Registering the memory outputs is a good idea.
//
// The registers get packed into the memory by the fitter
// which means minimal resources are consumed (the result
// is a altsyncram with registered outputs, available on
// all modern Altera devices).
//
// This output stage acts as an extra slot in the FIFO,
// and complicates the fill level.
// --------------------------------------------------
generate if (EMPTY_LATENCY == 3) begin : gen_blk15
always @(posedge clk or posedge reset) begin
if (reset) begin
out_valid <= 0;
out_payload <= 0;
end
else begin
if (internal_out_ready) begin
out_valid <= internal_out_valid & ok_to_forward;
out_payload <= internal_out_payload;
end
end
end
end
else begin : gen_blk15_else
always @* begin
out_valid = internal_out_valid;
out_payload = internal_out_payload;
end
end
endgenerate
// --------------------------------------------------
// Fill Level
//
// The fill level is calculated from the next write
// and read pointers to avoid unnecessary latency
// and logic.
//
// However, if the store-and-forward mode of the FIFO
// is enabled, the fill level is an up-down counter
// for fmax optimization reasons.
//
// If the output pipeline is enabled, the fill level
// must account for it, or we'll always be off by one.
// This may, or may not be important depending on the
// application.
//
// For now, we'll always calculate the exact fill level
// at the cost of an extra adder when the output stage
// is enabled.
// --------------------------------------------------
generate if (USE_FILL_LEVEL) begin : gen_blk16
wire [31:0] depth32;
assign depth32 = DEPTH;
if (USE_STORE_FORWARD) begin
reg [ADDR_WIDTH : 0] curr_packet_len_less_one;
// --------------------------------------------------
// We only drop on endofpacket. As long as we don't add to the fill
// level on the dropped endofpacket cycle, we can simply subtract
// (packet length - 1) from the fill level for dropped packets.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
curr_packet_len_less_one <= 0;
end else begin
if (write) begin
curr_packet_len_less_one <= curr_packet_len_less_one + 1'b1;
if (in_endofpacket)
curr_packet_len_less_one <= 0;
end
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
fifo_fill_level <= 0;
end else if (drop_on_error) begin
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one;
if (read)
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one - 1'b1;
end else if (write && !read) begin
fifo_fill_level <= fifo_fill_level + 1'b1;
end else if (read && !write) begin
fifo_fill_level <= fifo_fill_level - 1'b1;
end
end
end else begin
always @(posedge clk or posedge reset) begin
if (reset)
fifo_fill_level <= 0;
else if (next_full & !drop_on_error)
fifo_fill_level <= depth32[ADDR_WIDTH:0];
else begin
fifo_fill_level[ADDR_WIDTH] <= 1'b0;
fifo_fill_level[ADDR_WIDTH-1 : 0] <= next_wr_ptr - next_rd_ptr;
end
end
end
always @* begin
fill_level = fifo_fill_level;
if (EMPTY_LATENCY == 3)
fill_level = fifo_fill_level + {{ADDR_WIDTH{1'b0}}, out_valid};
end
end
else begin : gen_blk16_else
always @* begin
fill_level = 0;
end
end
endgenerate
generate if (USE_ALMOST_FULL_IF) begin : gen_blk17
assign almost_full_data = (fill_level >= almost_full_threshold);
end
else
assign almost_full_data = 0;
endgenerate
generate if (USE_ALMOST_EMPTY_IF) begin : gen_blk18
assign almost_empty_data = (fill_level <= almost_empty_threshold);
end
else
assign almost_empty_data = 0;
endgenerate
// --------------------------------------------------
// Avalon-MM Status & Control Connection Point
//
// Register map:
//
// | Addr | RW | 31 - 0 |
// | 0 | R | Fill level |
//
// The registering of this connection point means
// that there is a cycle of latency between
// reads/writes and the updating of the fill level.
// --------------------------------------------------
generate if (USE_STORE_FORWARD) begin : gen_blk19
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
cut_through_threshold <= 0;
drop_on_error_en <= 0;
csr_readdata <= 0;
pkt_mode <= 1'b1;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 5)
csr_readdata <= {31'b0, drop_on_error_en};
else if (csr_address == 4)
csr_readdata <= {8'b0, cut_through_threshold};
else if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b101)
drop_on_error_en <= csr_writedata[0];
else if(csr_address == 3'b100) begin
cut_through_threshold <= csr_writedata[23:0];
pkt_mode <= (csr_writedata[23:0] == 0);
end
else if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else if (USE_ALMOST_FULL_IF || USE_ALMOST_EMPTY_IF) begin : gen_blk19_else1
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
csr_readdata <= 0;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else begin : gen_blk19_else2
always @(posedge clk or posedge reset) begin
if (reset) begin
csr_readdata <= 0;
end
else if (csr_read) begin
csr_readdata <= 0;
if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
end
end
endgenerate
// --------------------------------------------------
// Store and forward logic
// --------------------------------------------------
// if the fifo gets full before the entire packet or the
// cut-threshold condition is met then start sending out
// data in order to avoid dead-lock situation
generate if (USE_STORE_FORWARD) begin : gen_blk20
assign wait_for_threshold = (fifo_fill_level_lt_cut_through_threshold) & wait_for_pkt ;
assign wait_for_pkt = pkt_cnt_eq_zero | (pkt_cnt_eq_one & out_pkt_leave);
assign ok_to_forward = (pkt_mode ? (~wait_for_pkt | ~pkt_has_started) :
~wait_for_threshold) | fifo_too_small_r;
assign in_pkt_eop_arrive = in_valid & in_ready & in_endofpacket;
assign in_pkt_start = in_valid & in_ready & in_startofpacket;
assign in_pkt_error = in_valid & in_ready & |in_error;
assign out_pkt_sop_leave = out_valid & out_ready & out_startofpacket;
assign out_pkt_leave = out_valid & out_ready & out_endofpacket;
assign fifo_too_small = (pkt_mode ? wait_for_pkt : wait_for_threshold) & full & out_ready;
// count packets coming and going into the fifo
always @(posedge clk or posedge reset) begin
if (reset) begin
pkt_cnt <= 0;
pkt_has_started <= 0;
sop_has_left_fifo <= 0;
fifo_too_small_r <= 0;
pkt_cnt_eq_zero <= 1'b1;
pkt_cnt_eq_one <= 1'b0;
fifo_fill_level_lt_cut_through_threshold <= 1'b1;
end
else begin
fifo_fill_level_lt_cut_through_threshold <= fifo_fill_level < cut_through_threshold;
fifo_too_small_r <= fifo_too_small;
if( in_pkt_eop_arrive )
sop_has_left_fifo <= 1'b0;
else if (out_pkt_sop_leave & pkt_cnt_eq_zero )
sop_has_left_fifo <= 1'b1;
if (in_pkt_eop_arrive & ~out_pkt_leave & ~drop_on_error ) begin
pkt_cnt <= pkt_cnt + 1'b1;
pkt_cnt_eq_zero <= 0;
if (pkt_cnt == 0)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
else if((~in_pkt_eop_arrive | drop_on_error) & out_pkt_leave) begin
pkt_cnt <= pkt_cnt - 1'b1;
if (pkt_cnt == 1)
pkt_cnt_eq_zero <= 1'b1;
else
pkt_cnt_eq_zero <= 1'b0;
if (pkt_cnt == 2)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
if (in_pkt_start)
pkt_has_started <= 1'b1;
else if (in_pkt_eop_arrive)
pkt_has_started <= 1'b0;
end
end
// drop on error logic
always @(posedge clk or posedge reset) begin
if (reset) begin
sop_ptr <= 0;
error_in_pkt <= 0;
end
else begin
// save the location of the SOP
if ( in_pkt_start )
sop_ptr <= wr_ptr;
// remember if error in pkt
// log error only if packet has already started
if (in_pkt_eop_arrive)
error_in_pkt <= 1'b0;
else if ( in_pkt_error & (pkt_has_started | in_pkt_start))
error_in_pkt <= 1'b1;
end
end
assign drop_on_error = drop_on_error_en & (error_in_pkt | in_pkt_error) & in_pkt_eop_arrive &
~sop_has_left_fifo & ~(out_pkt_sop_leave & pkt_cnt_eq_zero);
assign curr_sop_ptr = (write && in_startofpacket && in_endofpacket) ? wr_ptr : sop_ptr;
end
else begin : gen_blk20_else
assign ok_to_forward = 1'b1;
assign drop_on_error = 1'b0;
if (ADDR_WIDTH <= 1)
assign curr_sop_ptr = 1'b0;
else
assign curr_sop_ptr = {ADDR_WIDTH - 1 { 1'b0 }};
end
endgenerate
// --------------------------------------------------
// Calculates the log2ceil of the input value
// --------------------------------------------------
function integer log2ceil;
input integer val;
reg[31:0] i;
begin
i = 1;
log2ceil = 0;
while (i < val) begin
log2ceil = log2ceil + 1;
i = i[30:0] << 1;
end
end
endfunction
endmodule |
module altera_avalon_sc_fifo
#(
// --------------------------------------------------
// Parameters
// --------------------------------------------------
parameter SYMBOLS_PER_BEAT = 1,
parameter BITS_PER_SYMBOL = 8,
parameter FIFO_DEPTH = 16,
parameter CHANNEL_WIDTH = 0,
parameter ERROR_WIDTH = 0,
parameter USE_PACKETS = 0,
parameter USE_FILL_LEVEL = 0,
parameter USE_STORE_FORWARD = 0,
parameter USE_ALMOST_FULL_IF = 0,
parameter USE_ALMOST_EMPTY_IF = 0,
// --------------------------------------------------
// Empty latency is defined as the number of cycles
// required for a write to deassert the empty flag.
// For example, a latency of 1 means that the empty
// flag is deasserted on the cycle after a write.
//
// Another way to think of it is the latency for a
// write to propagate to the output.
//
// An empty latency of 0 implies lookahead, which is
// only implemented for the register-based FIFO.
// --------------------------------------------------
parameter EMPTY_LATENCY = 3,
parameter USE_MEMORY_BLOCKS = 1,
// --------------------------------------------------
// Internal Parameters
// --------------------------------------------------
parameter DATA_WIDTH = SYMBOLS_PER_BEAT * BITS_PER_SYMBOL,
parameter EMPTY_WIDTH = log2ceil(SYMBOLS_PER_BEAT)
)
(
// --------------------------------------------------
// Ports
// --------------------------------------------------
input clk,
input reset,
input [DATA_WIDTH-1: 0] in_data,
input in_valid,
input in_startofpacket,
input in_endofpacket,
input [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] in_empty,
input [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] in_error,
input [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] in_channel,
output in_ready,
output [DATA_WIDTH-1 : 0] out_data,
output reg out_valid,
output out_startofpacket,
output out_endofpacket,
output [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] out_empty,
output [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] out_error,
output [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] out_channel,
input out_ready,
input [(USE_STORE_FORWARD ? 2 : 1) : 0] csr_address,
input csr_write,
input csr_read,
input [31 : 0] csr_writedata,
output reg [31 : 0] csr_readdata,
output wire almost_full_data,
output wire almost_empty_data
);
// --------------------------------------------------
// Local Parameters
// --------------------------------------------------
localparam ADDR_WIDTH = log2ceil(FIFO_DEPTH);
localparam DEPTH = FIFO_DEPTH;
localparam PKT_SIGNALS_WIDTH = 2 + EMPTY_WIDTH;
localparam PAYLOAD_WIDTH = (USE_PACKETS == 1) ?
2 + EMPTY_WIDTH + DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH:
DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH;
// --------------------------------------------------
// Internal Signals
// --------------------------------------------------
genvar i;
reg [PAYLOAD_WIDTH-1 : 0] mem [DEPTH-1 : 0];
reg [ADDR_WIDTH-1 : 0] wr_ptr;
reg [ADDR_WIDTH-1 : 0] rd_ptr;
reg [DEPTH-1 : 0] mem_used;
wire [ADDR_WIDTH-1 : 0] next_wr_ptr;
wire [ADDR_WIDTH-1 : 0] next_rd_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_wr_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_rd_ptr;
wire [ADDR_WIDTH-1 : 0] mem_rd_ptr;
wire read;
wire write;
reg empty;
reg next_empty;
reg full;
reg next_full;
wire [PKT_SIGNALS_WIDTH-1 : 0] in_packet_signals;
wire [PKT_SIGNALS_WIDTH-1 : 0] out_packet_signals;
wire [PAYLOAD_WIDTH-1 : 0] in_payload;
reg [PAYLOAD_WIDTH-1 : 0] internal_out_payload;
reg [PAYLOAD_WIDTH-1 : 0] out_payload;
reg internal_out_valid;
wire internal_out_ready;
reg [ADDR_WIDTH : 0] fifo_fill_level;
reg [ADDR_WIDTH : 0] fill_level;
reg [ADDR_WIDTH-1 : 0] sop_ptr = 0;
wire [ADDR_WIDTH-1 : 0] curr_sop_ptr;
reg [23:0] almost_full_threshold;
reg [23:0] almost_empty_threshold;
reg [23:0] cut_through_threshold;
reg [15:0] pkt_cnt;
reg drop_on_error_en;
reg error_in_pkt;
reg pkt_has_started;
reg sop_has_left_fifo;
reg fifo_too_small_r;
reg pkt_cnt_eq_zero;
reg pkt_cnt_eq_one;
wire wait_for_threshold;
reg pkt_mode;
wire wait_for_pkt;
wire ok_to_forward;
wire in_pkt_eop_arrive;
wire out_pkt_leave;
wire in_pkt_start;
wire in_pkt_error;
wire drop_on_error;
wire fifo_too_small;
wire out_pkt_sop_leave;
wire [31:0] max_fifo_size;
reg fifo_fill_level_lt_cut_through_threshold;
// --------------------------------------------------
// Define Payload
//
// Icky part where we decide which signals form the
// payload to the FIFO with generate blocks.
// --------------------------------------------------
generate
if (EMPTY_WIDTH > 0) begin : gen_blk1
assign in_packet_signals = {in_startofpacket, in_endofpacket, in_empty};
assign {out_startofpacket, out_endofpacket, out_empty} = out_packet_signals;
end
else begin : gen_blk1_else
assign out_empty = in_error;
assign in_packet_signals = {in_startofpacket, in_endofpacket};
assign {out_startofpacket, out_endofpacket} = out_packet_signals;
end
endgenerate
generate
if (USE_PACKETS) begin : gen_blk2
if (ERROR_WIDTH > 0) begin : gen_blk3
if (CHANNEL_WIDTH > 0) begin : gen_blk4
assign in_payload = {in_packet_signals, in_data, in_error, in_channel};
assign {out_packet_signals, out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk4_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data, in_error};
assign {out_packet_signals, out_data, out_error} = out_payload;
end
end
else begin : gen_blk3_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk5
assign in_payload = {in_packet_signals, in_data, in_channel};
assign {out_packet_signals, out_data, out_channel} = out_payload;
end
else begin : gen_blk5_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data};
assign {out_packet_signals, out_data} = out_payload;
end
end
end
else begin : gen_blk2_else
assign out_packet_signals = 0;
if (ERROR_WIDTH > 0) begin : gen_blk6
if (CHANNEL_WIDTH > 0) begin : gen_blk7
assign in_payload = {in_data, in_error, in_channel};
assign {out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk7_else
assign out_channel = in_channel;
assign in_payload = {in_data, in_error};
assign {out_data, out_error} = out_payload;
end
end
else begin : gen_blk6_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk8
assign in_payload = {in_data, in_channel};
assign {out_data, out_channel} = out_payload;
end
else begin : gen_blk8_else
assign out_channel = in_channel;
assign in_payload = in_data;
assign out_data = out_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Memory-based FIFO storage
//
// To allow a ready latency of 0, the read index is
// obtained from the next read pointer and memory
// outputs are unregistered.
//
// If the empty latency is 1, we infer bypass logic
// around the memory so writes propagate to the
// outputs on the next cycle.
//
// Do not change the way this is coded: Quartus needs
// a perfect match to the template, and any attempt to
// refactor the two always blocks into one will break
// memory inference.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk9
if (EMPTY_LATENCY == 1) begin : gen_blk10
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] = in_payload;
internal_out_payload = mem[mem_rd_ptr];
end
end else begin : gen_blk10_else
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] <= in_payload;
internal_out_payload <= mem[mem_rd_ptr];
end
end
assign mem_rd_ptr = next_rd_ptr;
end else begin : gen_blk9_else
// --------------------------------------------------
// Register-based FIFO storage
//
// Uses a shift register as the storage element. Each
// shift register slot has a bit which indicates if
// the slot is occupied (credit to Sam H for the idea).
// The occupancy bits are contiguous and start from the
// lsb, so 0000, 0001, 0011, 0111, 1111 for a 4-deep
// FIFO.
//
// Each slot is enabled during a read or when it
// is unoccupied. New data is always written to every
// going-to-be-empty slot (we keep track of which ones
// are actually useful with the occupancy bits). On a
// read we shift occupied slots.
//
// The exception is the last slot, which always gets
// new data when it is unoccupied.
// --------------------------------------------------
for (i = 0; i < DEPTH-1; i = i + 1) begin : shift_reg
always @(posedge clk or posedge reset) begin
if (reset) begin
mem[i] <= 0;
end
else if (read || !mem_used[i]) begin
if (!mem_used[i+1])
mem[i] <= in_payload;
else
mem[i] <= mem[i+1];
end
end
end
always @(posedge clk, posedge reset) begin
if (reset) begin
mem[DEPTH-1] <= 0;
end
else begin
if (DEPTH == 1) begin
if (write)
mem[DEPTH-1] <= in_payload;
end
else if (!mem_used[DEPTH-1])
mem[DEPTH-1] <= in_payload;
end
end
end
endgenerate
assign read = internal_out_ready && internal_out_valid && ok_to_forward;
assign write = in_ready && in_valid;
// --------------------------------------------------
// Pointer Management
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk11
assign incremented_wr_ptr = wr_ptr + 1'b1;
assign incremented_rd_ptr = rd_ptr + 1'b1;
assign next_wr_ptr = drop_on_error ? curr_sop_ptr : write ? incremented_wr_ptr : wr_ptr;
assign next_rd_ptr = (read) ? incremented_rd_ptr : rd_ptr;
always @(posedge clk or posedge reset) begin
if (reset) begin
wr_ptr <= 0;
rd_ptr <= 0;
end
else begin
wr_ptr <= next_wr_ptr;
rd_ptr <= next_rd_ptr;
end
end
end else begin : gen_blk11_else
// --------------------------------------------------
// Shift Register Occupancy Bits
//
// Consider a 4-deep FIFO with 2 entries: 0011
// On a read and write, do not modify the bits.
// On a write, left-shift the bits to get 0111.
// On a read, right-shift the bits to get 0001.
//
// Also, on a write we set bit0 (the head), while
// clearing the tail on a read.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[0] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[0] <= 1;
else if (read) begin
if (DEPTH > 1)
mem_used[0] <= mem_used[1];
else
mem_used[0] <= 0;
end
end
end
end
if (DEPTH > 1) begin : gen_blk12
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[DEPTH-1] <= 0;
end
else begin
if (write ^ read) begin
mem_used[DEPTH-1] <= 0;
if (write)
mem_used[DEPTH-1] <= mem_used[DEPTH-2];
end
end
end
end
for (i = 1; i < DEPTH-1; i = i + 1) begin : storage_logic
always @(posedge clk, posedge reset) begin
if (reset) begin
mem_used[i] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[i] <= mem_used[i-1];
else if (read)
mem_used[i] <= mem_used[i+1];
end
end
end
end
end
endgenerate
// --------------------------------------------------
// Memory FIFO Status Management
//
// Generates the full and empty signals from the
// pointers. The FIFO is full when the next write
// pointer will be equal to the read pointer after
// a write. Reading from a FIFO clears full.
//
// The FIFO is empty when the next read pointer will
// be equal to the write pointer after a read. Writing
// to a FIFO clears empty.
//
// A simultaneous read and write must not change any of
// the empty or full flags unless there is a drop on error event.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk13
always @* begin
next_full = full;
next_empty = empty;
if (read && !write) begin
next_full = 1'b0;
if (incremented_rd_ptr == wr_ptr)
next_empty = 1'b1;
end
if (write && !read) begin
if (!drop_on_error)
next_empty = 1'b0;
else if (curr_sop_ptr == rd_ptr) // drop on error and only 1 pkt in fifo
next_empty = 1'b1;
if (incremented_wr_ptr == rd_ptr && !drop_on_error)
next_full = 1'b1;
end
if (write && read && drop_on_error) begin
if (curr_sop_ptr == next_rd_ptr)
next_empty = 1'b1;
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
empty <= 1;
full <= 0;
end
else begin
empty <= next_empty;
full <= next_full;
end
end
end else begin : gen_blk13_else
// --------------------------------------------------
// Register FIFO Status Management
//
// Full when the tail occupancy bit is 1. Empty when
// the head occupancy bit is 0.
// --------------------------------------------------
always @* begin
full = mem_used[DEPTH-1];
empty = !mem_used[0];
// ------------------------------------------
// For a single slot FIFO, reading clears the
// full status immediately.
// ------------------------------------------
if (DEPTH == 1)
full = mem_used[0] && !read;
internal_out_payload = mem[0];
// ------------------------------------------
// Writes clear empty immediately for lookahead modes.
// Note that we use in_valid instead of write to avoid
// combinational loops (in lookahead mode, qualifying
// with in_ready is meaningless).
//
// In a 1-deep FIFO, a possible combinational loop runs
// from write -> out_valid -> out_ready -> write
// ------------------------------------------
if (EMPTY_LATENCY == 0) begin
empty = !mem_used[0] && !in_valid;
if (!mem_used[0] && in_valid)
internal_out_payload = in_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Avalon-ST Signals
//
// The in_ready signal is straightforward.
//
// To match memory latency when empty latency > 1,
// out_valid assertions must be delayed by one clock
// cycle.
//
// Note: out_valid deassertions must not be delayed or
// the FIFO will underflow.
// --------------------------------------------------
assign in_ready = !full;
assign internal_out_ready = out_ready || !out_valid;
generate if (EMPTY_LATENCY > 1) begin : gen_blk14
always @(posedge clk or posedge reset) begin
if (reset)
internal_out_valid <= 0;
else begin
internal_out_valid <= !empty & ok_to_forward & ~drop_on_error;
if (read) begin
if (incremented_rd_ptr == wr_ptr)
internal_out_valid <= 1'b0;
end
end
end
end else begin : gen_blk14_else
always @* begin
internal_out_valid = !empty & ok_to_forward;
end
end
endgenerate
// --------------------------------------------------
// Single Output Pipeline Stage
//
// This output pipeline stage is enabled if the FIFO's
// empty latency is set to 3 (default). It is disabled
// for all other allowed latencies.
//
// Reason: The memory outputs are unregistered, so we have to
// register the output or fmax will drop if combinatorial
// logic is present on the output datapath.
//
// Q: The Avalon-ST spec says that I have to register my outputs
// But isn't the memory counted as a register?
// A: The path from the address lookup to the memory output is
// slow. Registering the memory outputs is a good idea.
//
// The registers get packed into the memory by the fitter
// which means minimal resources are consumed (the result
// is a altsyncram with registered outputs, available on
// all modern Altera devices).
//
// This output stage acts as an extra slot in the FIFO,
// and complicates the fill level.
// --------------------------------------------------
generate if (EMPTY_LATENCY == 3) begin : gen_blk15
always @(posedge clk or posedge reset) begin
if (reset) begin
out_valid <= 0;
out_payload <= 0;
end
else begin
if (internal_out_ready) begin
out_valid <= internal_out_valid & ok_to_forward;
out_payload <= internal_out_payload;
end
end
end
end
else begin : gen_blk15_else
always @* begin
out_valid = internal_out_valid;
out_payload = internal_out_payload;
end
end
endgenerate
// --------------------------------------------------
// Fill Level
//
// The fill level is calculated from the next write
// and read pointers to avoid unnecessary latency
// and logic.
//
// However, if the store-and-forward mode of the FIFO
// is enabled, the fill level is an up-down counter
// for fmax optimization reasons.
//
// If the output pipeline is enabled, the fill level
// must account for it, or we'll always be off by one.
// This may, or may not be important depending on the
// application.
//
// For now, we'll always calculate the exact fill level
// at the cost of an extra adder when the output stage
// is enabled.
// --------------------------------------------------
generate if (USE_FILL_LEVEL) begin : gen_blk16
wire [31:0] depth32;
assign depth32 = DEPTH;
if (USE_STORE_FORWARD) begin
reg [ADDR_WIDTH : 0] curr_packet_len_less_one;
// --------------------------------------------------
// We only drop on endofpacket. As long as we don't add to the fill
// level on the dropped endofpacket cycle, we can simply subtract
// (packet length - 1) from the fill level for dropped packets.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
curr_packet_len_less_one <= 0;
end else begin
if (write) begin
curr_packet_len_less_one <= curr_packet_len_less_one + 1'b1;
if (in_endofpacket)
curr_packet_len_less_one <= 0;
end
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
fifo_fill_level <= 0;
end else if (drop_on_error) begin
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one;
if (read)
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one - 1'b1;
end else if (write && !read) begin
fifo_fill_level <= fifo_fill_level + 1'b1;
end else if (read && !write) begin
fifo_fill_level <= fifo_fill_level - 1'b1;
end
end
end else begin
always @(posedge clk or posedge reset) begin
if (reset)
fifo_fill_level <= 0;
else if (next_full & !drop_on_error)
fifo_fill_level <= depth32[ADDR_WIDTH:0];
else begin
fifo_fill_level[ADDR_WIDTH] <= 1'b0;
fifo_fill_level[ADDR_WIDTH-1 : 0] <= next_wr_ptr - next_rd_ptr;
end
end
end
always @* begin
fill_level = fifo_fill_level;
if (EMPTY_LATENCY == 3)
fill_level = fifo_fill_level + {{ADDR_WIDTH{1'b0}}, out_valid};
end
end
else begin : gen_blk16_else
always @* begin
fill_level = 0;
end
end
endgenerate
generate if (USE_ALMOST_FULL_IF) begin : gen_blk17
assign almost_full_data = (fill_level >= almost_full_threshold);
end
else
assign almost_full_data = 0;
endgenerate
generate if (USE_ALMOST_EMPTY_IF) begin : gen_blk18
assign almost_empty_data = (fill_level <= almost_empty_threshold);
end
else
assign almost_empty_data = 0;
endgenerate
// --------------------------------------------------
// Avalon-MM Status & Control Connection Point
//
// Register map:
//
// | Addr | RW | 31 - 0 |
// | 0 | R | Fill level |
//
// The registering of this connection point means
// that there is a cycle of latency between
// reads/writes and the updating of the fill level.
// --------------------------------------------------
generate if (USE_STORE_FORWARD) begin : gen_blk19
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
cut_through_threshold <= 0;
drop_on_error_en <= 0;
csr_readdata <= 0;
pkt_mode <= 1'b1;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 5)
csr_readdata <= {31'b0, drop_on_error_en};
else if (csr_address == 4)
csr_readdata <= {8'b0, cut_through_threshold};
else if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b101)
drop_on_error_en <= csr_writedata[0];
else if(csr_address == 3'b100) begin
cut_through_threshold <= csr_writedata[23:0];
pkt_mode <= (csr_writedata[23:0] == 0);
end
else if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else if (USE_ALMOST_FULL_IF || USE_ALMOST_EMPTY_IF) begin : gen_blk19_else1
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
csr_readdata <= 0;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else begin : gen_blk19_else2
always @(posedge clk or posedge reset) begin
if (reset) begin
csr_readdata <= 0;
end
else if (csr_read) begin
csr_readdata <= 0;
if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
end
end
endgenerate
// --------------------------------------------------
// Store and forward logic
// --------------------------------------------------
// if the fifo gets full before the entire packet or the
// cut-threshold condition is met then start sending out
// data in order to avoid dead-lock situation
generate if (USE_STORE_FORWARD) begin : gen_blk20
assign wait_for_threshold = (fifo_fill_level_lt_cut_through_threshold) & wait_for_pkt ;
assign wait_for_pkt = pkt_cnt_eq_zero | (pkt_cnt_eq_one & out_pkt_leave);
assign ok_to_forward = (pkt_mode ? (~wait_for_pkt | ~pkt_has_started) :
~wait_for_threshold) | fifo_too_small_r;
assign in_pkt_eop_arrive = in_valid & in_ready & in_endofpacket;
assign in_pkt_start = in_valid & in_ready & in_startofpacket;
assign in_pkt_error = in_valid & in_ready & |in_error;
assign out_pkt_sop_leave = out_valid & out_ready & out_startofpacket;
assign out_pkt_leave = out_valid & out_ready & out_endofpacket;
assign fifo_too_small = (pkt_mode ? wait_for_pkt : wait_for_threshold) & full & out_ready;
// count packets coming and going into the fifo
always @(posedge clk or posedge reset) begin
if (reset) begin
pkt_cnt <= 0;
pkt_has_started <= 0;
sop_has_left_fifo <= 0;
fifo_too_small_r <= 0;
pkt_cnt_eq_zero <= 1'b1;
pkt_cnt_eq_one <= 1'b0;
fifo_fill_level_lt_cut_through_threshold <= 1'b1;
end
else begin
fifo_fill_level_lt_cut_through_threshold <= fifo_fill_level < cut_through_threshold;
fifo_too_small_r <= fifo_too_small;
if( in_pkt_eop_arrive )
sop_has_left_fifo <= 1'b0;
else if (out_pkt_sop_leave & pkt_cnt_eq_zero )
sop_has_left_fifo <= 1'b1;
if (in_pkt_eop_arrive & ~out_pkt_leave & ~drop_on_error ) begin
pkt_cnt <= pkt_cnt + 1'b1;
pkt_cnt_eq_zero <= 0;
if (pkt_cnt == 0)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
else if((~in_pkt_eop_arrive | drop_on_error) & out_pkt_leave) begin
pkt_cnt <= pkt_cnt - 1'b1;
if (pkt_cnt == 1)
pkt_cnt_eq_zero <= 1'b1;
else
pkt_cnt_eq_zero <= 1'b0;
if (pkt_cnt == 2)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
if (in_pkt_start)
pkt_has_started <= 1'b1;
else if (in_pkt_eop_arrive)
pkt_has_started <= 1'b0;
end
end
// drop on error logic
always @(posedge clk or posedge reset) begin
if (reset) begin
sop_ptr <= 0;
error_in_pkt <= 0;
end
else begin
// save the location of the SOP
if ( in_pkt_start )
sop_ptr <= wr_ptr;
// remember if error in pkt
// log error only if packet has already started
if (in_pkt_eop_arrive)
error_in_pkt <= 1'b0;
else if ( in_pkt_error & (pkt_has_started | in_pkt_start))
error_in_pkt <= 1'b1;
end
end
assign drop_on_error = drop_on_error_en & (error_in_pkt | in_pkt_error) & in_pkt_eop_arrive &
~sop_has_left_fifo & ~(out_pkt_sop_leave & pkt_cnt_eq_zero);
assign curr_sop_ptr = (write && in_startofpacket && in_endofpacket) ? wr_ptr : sop_ptr;
end
else begin : gen_blk20_else
assign ok_to_forward = 1'b1;
assign drop_on_error = 1'b0;
if (ADDR_WIDTH <= 1)
assign curr_sop_ptr = 1'b0;
else
assign curr_sop_ptr = {ADDR_WIDTH - 1 { 1'b0 }};
end
endgenerate
// --------------------------------------------------
// Calculates the log2ceil of the input value
// --------------------------------------------------
function integer log2ceil;
input integer val;
reg[31:0] i;
begin
i = 1;
log2ceil = 0;
while (i < val) begin
log2ceil = log2ceil + 1;
i = i[30:0] << 1;
end
end
endfunction
endmodule |
module altera_avalon_sc_fifo
#(
// --------------------------------------------------
// Parameters
// --------------------------------------------------
parameter SYMBOLS_PER_BEAT = 1,
parameter BITS_PER_SYMBOL = 8,
parameter FIFO_DEPTH = 16,
parameter CHANNEL_WIDTH = 0,
parameter ERROR_WIDTH = 0,
parameter USE_PACKETS = 0,
parameter USE_FILL_LEVEL = 0,
parameter USE_STORE_FORWARD = 0,
parameter USE_ALMOST_FULL_IF = 0,
parameter USE_ALMOST_EMPTY_IF = 0,
// --------------------------------------------------
// Empty latency is defined as the number of cycles
// required for a write to deassert the empty flag.
// For example, a latency of 1 means that the empty
// flag is deasserted on the cycle after a write.
//
// Another way to think of it is the latency for a
// write to propagate to the output.
//
// An empty latency of 0 implies lookahead, which is
// only implemented for the register-based FIFO.
// --------------------------------------------------
parameter EMPTY_LATENCY = 3,
parameter USE_MEMORY_BLOCKS = 1,
// --------------------------------------------------
// Internal Parameters
// --------------------------------------------------
parameter DATA_WIDTH = SYMBOLS_PER_BEAT * BITS_PER_SYMBOL,
parameter EMPTY_WIDTH = log2ceil(SYMBOLS_PER_BEAT)
)
(
// --------------------------------------------------
// Ports
// --------------------------------------------------
input clk,
input reset,
input [DATA_WIDTH-1: 0] in_data,
input in_valid,
input in_startofpacket,
input in_endofpacket,
input [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] in_empty,
input [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] in_error,
input [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] in_channel,
output in_ready,
output [DATA_WIDTH-1 : 0] out_data,
output reg out_valid,
output out_startofpacket,
output out_endofpacket,
output [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] out_empty,
output [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] out_error,
output [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] out_channel,
input out_ready,
input [(USE_STORE_FORWARD ? 2 : 1) : 0] csr_address,
input csr_write,
input csr_read,
input [31 : 0] csr_writedata,
output reg [31 : 0] csr_readdata,
output wire almost_full_data,
output wire almost_empty_data
);
// --------------------------------------------------
// Local Parameters
// --------------------------------------------------
localparam ADDR_WIDTH = log2ceil(FIFO_DEPTH);
localparam DEPTH = FIFO_DEPTH;
localparam PKT_SIGNALS_WIDTH = 2 + EMPTY_WIDTH;
localparam PAYLOAD_WIDTH = (USE_PACKETS == 1) ?
2 + EMPTY_WIDTH + DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH:
DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH;
// --------------------------------------------------
// Internal Signals
// --------------------------------------------------
genvar i;
reg [PAYLOAD_WIDTH-1 : 0] mem [DEPTH-1 : 0];
reg [ADDR_WIDTH-1 : 0] wr_ptr;
reg [ADDR_WIDTH-1 : 0] rd_ptr;
reg [DEPTH-1 : 0] mem_used;
wire [ADDR_WIDTH-1 : 0] next_wr_ptr;
wire [ADDR_WIDTH-1 : 0] next_rd_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_wr_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_rd_ptr;
wire [ADDR_WIDTH-1 : 0] mem_rd_ptr;
wire read;
wire write;
reg empty;
reg next_empty;
reg full;
reg next_full;
wire [PKT_SIGNALS_WIDTH-1 : 0] in_packet_signals;
wire [PKT_SIGNALS_WIDTH-1 : 0] out_packet_signals;
wire [PAYLOAD_WIDTH-1 : 0] in_payload;
reg [PAYLOAD_WIDTH-1 : 0] internal_out_payload;
reg [PAYLOAD_WIDTH-1 : 0] out_payload;
reg internal_out_valid;
wire internal_out_ready;
reg [ADDR_WIDTH : 0] fifo_fill_level;
reg [ADDR_WIDTH : 0] fill_level;
reg [ADDR_WIDTH-1 : 0] sop_ptr = 0;
wire [ADDR_WIDTH-1 : 0] curr_sop_ptr;
reg [23:0] almost_full_threshold;
reg [23:0] almost_empty_threshold;
reg [23:0] cut_through_threshold;
reg [15:0] pkt_cnt;
reg drop_on_error_en;
reg error_in_pkt;
reg pkt_has_started;
reg sop_has_left_fifo;
reg fifo_too_small_r;
reg pkt_cnt_eq_zero;
reg pkt_cnt_eq_one;
wire wait_for_threshold;
reg pkt_mode;
wire wait_for_pkt;
wire ok_to_forward;
wire in_pkt_eop_arrive;
wire out_pkt_leave;
wire in_pkt_start;
wire in_pkt_error;
wire drop_on_error;
wire fifo_too_small;
wire out_pkt_sop_leave;
wire [31:0] max_fifo_size;
reg fifo_fill_level_lt_cut_through_threshold;
// --------------------------------------------------
// Define Payload
//
// Icky part where we decide which signals form the
// payload to the FIFO with generate blocks.
// --------------------------------------------------
generate
if (EMPTY_WIDTH > 0) begin : gen_blk1
assign in_packet_signals = {in_startofpacket, in_endofpacket, in_empty};
assign {out_startofpacket, out_endofpacket, out_empty} = out_packet_signals;
end
else begin : gen_blk1_else
assign out_empty = in_error;
assign in_packet_signals = {in_startofpacket, in_endofpacket};
assign {out_startofpacket, out_endofpacket} = out_packet_signals;
end
endgenerate
generate
if (USE_PACKETS) begin : gen_blk2
if (ERROR_WIDTH > 0) begin : gen_blk3
if (CHANNEL_WIDTH > 0) begin : gen_blk4
assign in_payload = {in_packet_signals, in_data, in_error, in_channel};
assign {out_packet_signals, out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk4_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data, in_error};
assign {out_packet_signals, out_data, out_error} = out_payload;
end
end
else begin : gen_blk3_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk5
assign in_payload = {in_packet_signals, in_data, in_channel};
assign {out_packet_signals, out_data, out_channel} = out_payload;
end
else begin : gen_blk5_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data};
assign {out_packet_signals, out_data} = out_payload;
end
end
end
else begin : gen_blk2_else
assign out_packet_signals = 0;
if (ERROR_WIDTH > 0) begin : gen_blk6
if (CHANNEL_WIDTH > 0) begin : gen_blk7
assign in_payload = {in_data, in_error, in_channel};
assign {out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk7_else
assign out_channel = in_channel;
assign in_payload = {in_data, in_error};
assign {out_data, out_error} = out_payload;
end
end
else begin : gen_blk6_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk8
assign in_payload = {in_data, in_channel};
assign {out_data, out_channel} = out_payload;
end
else begin : gen_blk8_else
assign out_channel = in_channel;
assign in_payload = in_data;
assign out_data = out_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Memory-based FIFO storage
//
// To allow a ready latency of 0, the read index is
// obtained from the next read pointer and memory
// outputs are unregistered.
//
// If the empty latency is 1, we infer bypass logic
// around the memory so writes propagate to the
// outputs on the next cycle.
//
// Do not change the way this is coded: Quartus needs
// a perfect match to the template, and any attempt to
// refactor the two always blocks into one will break
// memory inference.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk9
if (EMPTY_LATENCY == 1) begin : gen_blk10
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] = in_payload;
internal_out_payload = mem[mem_rd_ptr];
end
end else begin : gen_blk10_else
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] <= in_payload;
internal_out_payload <= mem[mem_rd_ptr];
end
end
assign mem_rd_ptr = next_rd_ptr;
end else begin : gen_blk9_else
// --------------------------------------------------
// Register-based FIFO storage
//
// Uses a shift register as the storage element. Each
// shift register slot has a bit which indicates if
// the slot is occupied (credit to Sam H for the idea).
// The occupancy bits are contiguous and start from the
// lsb, so 0000, 0001, 0011, 0111, 1111 for a 4-deep
// FIFO.
//
// Each slot is enabled during a read or when it
// is unoccupied. New data is always written to every
// going-to-be-empty slot (we keep track of which ones
// are actually useful with the occupancy bits). On a
// read we shift occupied slots.
//
// The exception is the last slot, which always gets
// new data when it is unoccupied.
// --------------------------------------------------
for (i = 0; i < DEPTH-1; i = i + 1) begin : shift_reg
always @(posedge clk or posedge reset) begin
if (reset) begin
mem[i] <= 0;
end
else if (read || !mem_used[i]) begin
if (!mem_used[i+1])
mem[i] <= in_payload;
else
mem[i] <= mem[i+1];
end
end
end
always @(posedge clk, posedge reset) begin
if (reset) begin
mem[DEPTH-1] <= 0;
end
else begin
if (DEPTH == 1) begin
if (write)
mem[DEPTH-1] <= in_payload;
end
else if (!mem_used[DEPTH-1])
mem[DEPTH-1] <= in_payload;
end
end
end
endgenerate
assign read = internal_out_ready && internal_out_valid && ok_to_forward;
assign write = in_ready && in_valid;
// --------------------------------------------------
// Pointer Management
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk11
assign incremented_wr_ptr = wr_ptr + 1'b1;
assign incremented_rd_ptr = rd_ptr + 1'b1;
assign next_wr_ptr = drop_on_error ? curr_sop_ptr : write ? incremented_wr_ptr : wr_ptr;
assign next_rd_ptr = (read) ? incremented_rd_ptr : rd_ptr;
always @(posedge clk or posedge reset) begin
if (reset) begin
wr_ptr <= 0;
rd_ptr <= 0;
end
else begin
wr_ptr <= next_wr_ptr;
rd_ptr <= next_rd_ptr;
end
end
end else begin : gen_blk11_else
// --------------------------------------------------
// Shift Register Occupancy Bits
//
// Consider a 4-deep FIFO with 2 entries: 0011
// On a read and write, do not modify the bits.
// On a write, left-shift the bits to get 0111.
// On a read, right-shift the bits to get 0001.
//
// Also, on a write we set bit0 (the head), while
// clearing the tail on a read.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[0] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[0] <= 1;
else if (read) begin
if (DEPTH > 1)
mem_used[0] <= mem_used[1];
else
mem_used[0] <= 0;
end
end
end
end
if (DEPTH > 1) begin : gen_blk12
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[DEPTH-1] <= 0;
end
else begin
if (write ^ read) begin
mem_used[DEPTH-1] <= 0;
if (write)
mem_used[DEPTH-1] <= mem_used[DEPTH-2];
end
end
end
end
for (i = 1; i < DEPTH-1; i = i + 1) begin : storage_logic
always @(posedge clk, posedge reset) begin
if (reset) begin
mem_used[i] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[i] <= mem_used[i-1];
else if (read)
mem_used[i] <= mem_used[i+1];
end
end
end
end
end
endgenerate
// --------------------------------------------------
// Memory FIFO Status Management
//
// Generates the full and empty signals from the
// pointers. The FIFO is full when the next write
// pointer will be equal to the read pointer after
// a write. Reading from a FIFO clears full.
//
// The FIFO is empty when the next read pointer will
// be equal to the write pointer after a read. Writing
// to a FIFO clears empty.
//
// A simultaneous read and write must not change any of
// the empty or full flags unless there is a drop on error event.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk13
always @* begin
next_full = full;
next_empty = empty;
if (read && !write) begin
next_full = 1'b0;
if (incremented_rd_ptr == wr_ptr)
next_empty = 1'b1;
end
if (write && !read) begin
if (!drop_on_error)
next_empty = 1'b0;
else if (curr_sop_ptr == rd_ptr) // drop on error and only 1 pkt in fifo
next_empty = 1'b1;
if (incremented_wr_ptr == rd_ptr && !drop_on_error)
next_full = 1'b1;
end
if (write && read && drop_on_error) begin
if (curr_sop_ptr == next_rd_ptr)
next_empty = 1'b1;
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
empty <= 1;
full <= 0;
end
else begin
empty <= next_empty;
full <= next_full;
end
end
end else begin : gen_blk13_else
// --------------------------------------------------
// Register FIFO Status Management
//
// Full when the tail occupancy bit is 1. Empty when
// the head occupancy bit is 0.
// --------------------------------------------------
always @* begin
full = mem_used[DEPTH-1];
empty = !mem_used[0];
// ------------------------------------------
// For a single slot FIFO, reading clears the
// full status immediately.
// ------------------------------------------
if (DEPTH == 1)
full = mem_used[0] && !read;
internal_out_payload = mem[0];
// ------------------------------------------
// Writes clear empty immediately for lookahead modes.
// Note that we use in_valid instead of write to avoid
// combinational loops (in lookahead mode, qualifying
// with in_ready is meaningless).
//
// In a 1-deep FIFO, a possible combinational loop runs
// from write -> out_valid -> out_ready -> write
// ------------------------------------------
if (EMPTY_LATENCY == 0) begin
empty = !mem_used[0] && !in_valid;
if (!mem_used[0] && in_valid)
internal_out_payload = in_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Avalon-ST Signals
//
// The in_ready signal is straightforward.
//
// To match memory latency when empty latency > 1,
// out_valid assertions must be delayed by one clock
// cycle.
//
// Note: out_valid deassertions must not be delayed or
// the FIFO will underflow.
// --------------------------------------------------
assign in_ready = !full;
assign internal_out_ready = out_ready || !out_valid;
generate if (EMPTY_LATENCY > 1) begin : gen_blk14
always @(posedge clk or posedge reset) begin
if (reset)
internal_out_valid <= 0;
else begin
internal_out_valid <= !empty & ok_to_forward & ~drop_on_error;
if (read) begin
if (incremented_rd_ptr == wr_ptr)
internal_out_valid <= 1'b0;
end
end
end
end else begin : gen_blk14_else
always @* begin
internal_out_valid = !empty & ok_to_forward;
end
end
endgenerate
// --------------------------------------------------
// Single Output Pipeline Stage
//
// This output pipeline stage is enabled if the FIFO's
// empty latency is set to 3 (default). It is disabled
// for all other allowed latencies.
//
// Reason: The memory outputs are unregistered, so we have to
// register the output or fmax will drop if combinatorial
// logic is present on the output datapath.
//
// Q: The Avalon-ST spec says that I have to register my outputs
// But isn't the memory counted as a register?
// A: The path from the address lookup to the memory output is
// slow. Registering the memory outputs is a good idea.
//
// The registers get packed into the memory by the fitter
// which means minimal resources are consumed (the result
// is a altsyncram with registered outputs, available on
// all modern Altera devices).
//
// This output stage acts as an extra slot in the FIFO,
// and complicates the fill level.
// --------------------------------------------------
generate if (EMPTY_LATENCY == 3) begin : gen_blk15
always @(posedge clk or posedge reset) begin
if (reset) begin
out_valid <= 0;
out_payload <= 0;
end
else begin
if (internal_out_ready) begin
out_valid <= internal_out_valid & ok_to_forward;
out_payload <= internal_out_payload;
end
end
end
end
else begin : gen_blk15_else
always @* begin
out_valid = internal_out_valid;
out_payload = internal_out_payload;
end
end
endgenerate
// --------------------------------------------------
// Fill Level
//
// The fill level is calculated from the next write
// and read pointers to avoid unnecessary latency
// and logic.
//
// However, if the store-and-forward mode of the FIFO
// is enabled, the fill level is an up-down counter
// for fmax optimization reasons.
//
// If the output pipeline is enabled, the fill level
// must account for it, or we'll always be off by one.
// This may, or may not be important depending on the
// application.
//
// For now, we'll always calculate the exact fill level
// at the cost of an extra adder when the output stage
// is enabled.
// --------------------------------------------------
generate if (USE_FILL_LEVEL) begin : gen_blk16
wire [31:0] depth32;
assign depth32 = DEPTH;
if (USE_STORE_FORWARD) begin
reg [ADDR_WIDTH : 0] curr_packet_len_less_one;
// --------------------------------------------------
// We only drop on endofpacket. As long as we don't add to the fill
// level on the dropped endofpacket cycle, we can simply subtract
// (packet length - 1) from the fill level for dropped packets.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
curr_packet_len_less_one <= 0;
end else begin
if (write) begin
curr_packet_len_less_one <= curr_packet_len_less_one + 1'b1;
if (in_endofpacket)
curr_packet_len_less_one <= 0;
end
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
fifo_fill_level <= 0;
end else if (drop_on_error) begin
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one;
if (read)
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one - 1'b1;
end else if (write && !read) begin
fifo_fill_level <= fifo_fill_level + 1'b1;
end else if (read && !write) begin
fifo_fill_level <= fifo_fill_level - 1'b1;
end
end
end else begin
always @(posedge clk or posedge reset) begin
if (reset)
fifo_fill_level <= 0;
else if (next_full & !drop_on_error)
fifo_fill_level <= depth32[ADDR_WIDTH:0];
else begin
fifo_fill_level[ADDR_WIDTH] <= 1'b0;
fifo_fill_level[ADDR_WIDTH-1 : 0] <= next_wr_ptr - next_rd_ptr;
end
end
end
always @* begin
fill_level = fifo_fill_level;
if (EMPTY_LATENCY == 3)
fill_level = fifo_fill_level + {{ADDR_WIDTH{1'b0}}, out_valid};
end
end
else begin : gen_blk16_else
always @* begin
fill_level = 0;
end
end
endgenerate
generate if (USE_ALMOST_FULL_IF) begin : gen_blk17
assign almost_full_data = (fill_level >= almost_full_threshold);
end
else
assign almost_full_data = 0;
endgenerate
generate if (USE_ALMOST_EMPTY_IF) begin : gen_blk18
assign almost_empty_data = (fill_level <= almost_empty_threshold);
end
else
assign almost_empty_data = 0;
endgenerate
// --------------------------------------------------
// Avalon-MM Status & Control Connection Point
//
// Register map:
//
// | Addr | RW | 31 - 0 |
// | 0 | R | Fill level |
//
// The registering of this connection point means
// that there is a cycle of latency between
// reads/writes and the updating of the fill level.
// --------------------------------------------------
generate if (USE_STORE_FORWARD) begin : gen_blk19
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
cut_through_threshold <= 0;
drop_on_error_en <= 0;
csr_readdata <= 0;
pkt_mode <= 1'b1;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 5)
csr_readdata <= {31'b0, drop_on_error_en};
else if (csr_address == 4)
csr_readdata <= {8'b0, cut_through_threshold};
else if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b101)
drop_on_error_en <= csr_writedata[0];
else if(csr_address == 3'b100) begin
cut_through_threshold <= csr_writedata[23:0];
pkt_mode <= (csr_writedata[23:0] == 0);
end
else if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else if (USE_ALMOST_FULL_IF || USE_ALMOST_EMPTY_IF) begin : gen_blk19_else1
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
csr_readdata <= 0;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else begin : gen_blk19_else2
always @(posedge clk or posedge reset) begin
if (reset) begin
csr_readdata <= 0;
end
else if (csr_read) begin
csr_readdata <= 0;
if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
end
end
endgenerate
// --------------------------------------------------
// Store and forward logic
// --------------------------------------------------
// if the fifo gets full before the entire packet or the
// cut-threshold condition is met then start sending out
// data in order to avoid dead-lock situation
generate if (USE_STORE_FORWARD) begin : gen_blk20
assign wait_for_threshold = (fifo_fill_level_lt_cut_through_threshold) & wait_for_pkt ;
assign wait_for_pkt = pkt_cnt_eq_zero | (pkt_cnt_eq_one & out_pkt_leave);
assign ok_to_forward = (pkt_mode ? (~wait_for_pkt | ~pkt_has_started) :
~wait_for_threshold) | fifo_too_small_r;
assign in_pkt_eop_arrive = in_valid & in_ready & in_endofpacket;
assign in_pkt_start = in_valid & in_ready & in_startofpacket;
assign in_pkt_error = in_valid & in_ready & |in_error;
assign out_pkt_sop_leave = out_valid & out_ready & out_startofpacket;
assign out_pkt_leave = out_valid & out_ready & out_endofpacket;
assign fifo_too_small = (pkt_mode ? wait_for_pkt : wait_for_threshold) & full & out_ready;
// count packets coming and going into the fifo
always @(posedge clk or posedge reset) begin
if (reset) begin
pkt_cnt <= 0;
pkt_has_started <= 0;
sop_has_left_fifo <= 0;
fifo_too_small_r <= 0;
pkt_cnt_eq_zero <= 1'b1;
pkt_cnt_eq_one <= 1'b0;
fifo_fill_level_lt_cut_through_threshold <= 1'b1;
end
else begin
fifo_fill_level_lt_cut_through_threshold <= fifo_fill_level < cut_through_threshold;
fifo_too_small_r <= fifo_too_small;
if( in_pkt_eop_arrive )
sop_has_left_fifo <= 1'b0;
else if (out_pkt_sop_leave & pkt_cnt_eq_zero )
sop_has_left_fifo <= 1'b1;
if (in_pkt_eop_arrive & ~out_pkt_leave & ~drop_on_error ) begin
pkt_cnt <= pkt_cnt + 1'b1;
pkt_cnt_eq_zero <= 0;
if (pkt_cnt == 0)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
else if((~in_pkt_eop_arrive | drop_on_error) & out_pkt_leave) begin
pkt_cnt <= pkt_cnt - 1'b1;
if (pkt_cnt == 1)
pkt_cnt_eq_zero <= 1'b1;
else
pkt_cnt_eq_zero <= 1'b0;
if (pkt_cnt == 2)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
if (in_pkt_start)
pkt_has_started <= 1'b1;
else if (in_pkt_eop_arrive)
pkt_has_started <= 1'b0;
end
end
// drop on error logic
always @(posedge clk or posedge reset) begin
if (reset) begin
sop_ptr <= 0;
error_in_pkt <= 0;
end
else begin
// save the location of the SOP
if ( in_pkt_start )
sop_ptr <= wr_ptr;
// remember if error in pkt
// log error only if packet has already started
if (in_pkt_eop_arrive)
error_in_pkt <= 1'b0;
else if ( in_pkt_error & (pkt_has_started | in_pkt_start))
error_in_pkt <= 1'b1;
end
end
assign drop_on_error = drop_on_error_en & (error_in_pkt | in_pkt_error) & in_pkt_eop_arrive &
~sop_has_left_fifo & ~(out_pkt_sop_leave & pkt_cnt_eq_zero);
assign curr_sop_ptr = (write && in_startofpacket && in_endofpacket) ? wr_ptr : sop_ptr;
end
else begin : gen_blk20_else
assign ok_to_forward = 1'b1;
assign drop_on_error = 1'b0;
if (ADDR_WIDTH <= 1)
assign curr_sop_ptr = 1'b0;
else
assign curr_sop_ptr = {ADDR_WIDTH - 1 { 1'b0 }};
end
endgenerate
// --------------------------------------------------
// Calculates the log2ceil of the input value
// --------------------------------------------------
function integer log2ceil;
input integer val;
reg[31:0] i;
begin
i = 1;
log2ceil = 0;
while (i < val) begin
log2ceil = log2ceil + 1;
i = i[30:0] << 1;
end
end
endfunction
endmodule |
module altera_avalon_sc_fifo
#(
// --------------------------------------------------
// Parameters
// --------------------------------------------------
parameter SYMBOLS_PER_BEAT = 1,
parameter BITS_PER_SYMBOL = 8,
parameter FIFO_DEPTH = 16,
parameter CHANNEL_WIDTH = 0,
parameter ERROR_WIDTH = 0,
parameter USE_PACKETS = 0,
parameter USE_FILL_LEVEL = 0,
parameter USE_STORE_FORWARD = 0,
parameter USE_ALMOST_FULL_IF = 0,
parameter USE_ALMOST_EMPTY_IF = 0,
// --------------------------------------------------
// Empty latency is defined as the number of cycles
// required for a write to deassert the empty flag.
// For example, a latency of 1 means that the empty
// flag is deasserted on the cycle after a write.
//
// Another way to think of it is the latency for a
// write to propagate to the output.
//
// An empty latency of 0 implies lookahead, which is
// only implemented for the register-based FIFO.
// --------------------------------------------------
parameter EMPTY_LATENCY = 3,
parameter USE_MEMORY_BLOCKS = 1,
// --------------------------------------------------
// Internal Parameters
// --------------------------------------------------
parameter DATA_WIDTH = SYMBOLS_PER_BEAT * BITS_PER_SYMBOL,
parameter EMPTY_WIDTH = log2ceil(SYMBOLS_PER_BEAT)
)
(
// --------------------------------------------------
// Ports
// --------------------------------------------------
input clk,
input reset,
input [DATA_WIDTH-1: 0] in_data,
input in_valid,
input in_startofpacket,
input in_endofpacket,
input [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] in_empty,
input [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] in_error,
input [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] in_channel,
output in_ready,
output [DATA_WIDTH-1 : 0] out_data,
output reg out_valid,
output out_startofpacket,
output out_endofpacket,
output [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] out_empty,
output [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] out_error,
output [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] out_channel,
input out_ready,
input [(USE_STORE_FORWARD ? 2 : 1) : 0] csr_address,
input csr_write,
input csr_read,
input [31 : 0] csr_writedata,
output reg [31 : 0] csr_readdata,
output wire almost_full_data,
output wire almost_empty_data
);
// --------------------------------------------------
// Local Parameters
// --------------------------------------------------
localparam ADDR_WIDTH = log2ceil(FIFO_DEPTH);
localparam DEPTH = FIFO_DEPTH;
localparam PKT_SIGNALS_WIDTH = 2 + EMPTY_WIDTH;
localparam PAYLOAD_WIDTH = (USE_PACKETS == 1) ?
2 + EMPTY_WIDTH + DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH:
DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH;
// --------------------------------------------------
// Internal Signals
// --------------------------------------------------
genvar i;
reg [PAYLOAD_WIDTH-1 : 0] mem [DEPTH-1 : 0];
reg [ADDR_WIDTH-1 : 0] wr_ptr;
reg [ADDR_WIDTH-1 : 0] rd_ptr;
reg [DEPTH-1 : 0] mem_used;
wire [ADDR_WIDTH-1 : 0] next_wr_ptr;
wire [ADDR_WIDTH-1 : 0] next_rd_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_wr_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_rd_ptr;
wire [ADDR_WIDTH-1 : 0] mem_rd_ptr;
wire read;
wire write;
reg empty;
reg next_empty;
reg full;
reg next_full;
wire [PKT_SIGNALS_WIDTH-1 : 0] in_packet_signals;
wire [PKT_SIGNALS_WIDTH-1 : 0] out_packet_signals;
wire [PAYLOAD_WIDTH-1 : 0] in_payload;
reg [PAYLOAD_WIDTH-1 : 0] internal_out_payload;
reg [PAYLOAD_WIDTH-1 : 0] out_payload;
reg internal_out_valid;
wire internal_out_ready;
reg [ADDR_WIDTH : 0] fifo_fill_level;
reg [ADDR_WIDTH : 0] fill_level;
reg [ADDR_WIDTH-1 : 0] sop_ptr = 0;
wire [ADDR_WIDTH-1 : 0] curr_sop_ptr;
reg [23:0] almost_full_threshold;
reg [23:0] almost_empty_threshold;
reg [23:0] cut_through_threshold;
reg [15:0] pkt_cnt;
reg drop_on_error_en;
reg error_in_pkt;
reg pkt_has_started;
reg sop_has_left_fifo;
reg fifo_too_small_r;
reg pkt_cnt_eq_zero;
reg pkt_cnt_eq_one;
wire wait_for_threshold;
reg pkt_mode;
wire wait_for_pkt;
wire ok_to_forward;
wire in_pkt_eop_arrive;
wire out_pkt_leave;
wire in_pkt_start;
wire in_pkt_error;
wire drop_on_error;
wire fifo_too_small;
wire out_pkt_sop_leave;
wire [31:0] max_fifo_size;
reg fifo_fill_level_lt_cut_through_threshold;
// --------------------------------------------------
// Define Payload
//
// Icky part where we decide which signals form the
// payload to the FIFO with generate blocks.
// --------------------------------------------------
generate
if (EMPTY_WIDTH > 0) begin : gen_blk1
assign in_packet_signals = {in_startofpacket, in_endofpacket, in_empty};
assign {out_startofpacket, out_endofpacket, out_empty} = out_packet_signals;
end
else begin : gen_blk1_else
assign out_empty = in_error;
assign in_packet_signals = {in_startofpacket, in_endofpacket};
assign {out_startofpacket, out_endofpacket} = out_packet_signals;
end
endgenerate
generate
if (USE_PACKETS) begin : gen_blk2
if (ERROR_WIDTH > 0) begin : gen_blk3
if (CHANNEL_WIDTH > 0) begin : gen_blk4
assign in_payload = {in_packet_signals, in_data, in_error, in_channel};
assign {out_packet_signals, out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk4_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data, in_error};
assign {out_packet_signals, out_data, out_error} = out_payload;
end
end
else begin : gen_blk3_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk5
assign in_payload = {in_packet_signals, in_data, in_channel};
assign {out_packet_signals, out_data, out_channel} = out_payload;
end
else begin : gen_blk5_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data};
assign {out_packet_signals, out_data} = out_payload;
end
end
end
else begin : gen_blk2_else
assign out_packet_signals = 0;
if (ERROR_WIDTH > 0) begin : gen_blk6
if (CHANNEL_WIDTH > 0) begin : gen_blk7
assign in_payload = {in_data, in_error, in_channel};
assign {out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk7_else
assign out_channel = in_channel;
assign in_payload = {in_data, in_error};
assign {out_data, out_error} = out_payload;
end
end
else begin : gen_blk6_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk8
assign in_payload = {in_data, in_channel};
assign {out_data, out_channel} = out_payload;
end
else begin : gen_blk8_else
assign out_channel = in_channel;
assign in_payload = in_data;
assign out_data = out_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Memory-based FIFO storage
//
// To allow a ready latency of 0, the read index is
// obtained from the next read pointer and memory
// outputs are unregistered.
//
// If the empty latency is 1, we infer bypass logic
// around the memory so writes propagate to the
// outputs on the next cycle.
//
// Do not change the way this is coded: Quartus needs
// a perfect match to the template, and any attempt to
// refactor the two always blocks into one will break
// memory inference.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk9
if (EMPTY_LATENCY == 1) begin : gen_blk10
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] = in_payload;
internal_out_payload = mem[mem_rd_ptr];
end
end else begin : gen_blk10_else
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] <= in_payload;
internal_out_payload <= mem[mem_rd_ptr];
end
end
assign mem_rd_ptr = next_rd_ptr;
end else begin : gen_blk9_else
// --------------------------------------------------
// Register-based FIFO storage
//
// Uses a shift register as the storage element. Each
// shift register slot has a bit which indicates if
// the slot is occupied (credit to Sam H for the idea).
// The occupancy bits are contiguous and start from the
// lsb, so 0000, 0001, 0011, 0111, 1111 for a 4-deep
// FIFO.
//
// Each slot is enabled during a read or when it
// is unoccupied. New data is always written to every
// going-to-be-empty slot (we keep track of which ones
// are actually useful with the occupancy bits). On a
// read we shift occupied slots.
//
// The exception is the last slot, which always gets
// new data when it is unoccupied.
// --------------------------------------------------
for (i = 0; i < DEPTH-1; i = i + 1) begin : shift_reg
always @(posedge clk or posedge reset) begin
if (reset) begin
mem[i] <= 0;
end
else if (read || !mem_used[i]) begin
if (!mem_used[i+1])
mem[i] <= in_payload;
else
mem[i] <= mem[i+1];
end
end
end
always @(posedge clk, posedge reset) begin
if (reset) begin
mem[DEPTH-1] <= 0;
end
else begin
if (DEPTH == 1) begin
if (write)
mem[DEPTH-1] <= in_payload;
end
else if (!mem_used[DEPTH-1])
mem[DEPTH-1] <= in_payload;
end
end
end
endgenerate
assign read = internal_out_ready && internal_out_valid && ok_to_forward;
assign write = in_ready && in_valid;
// --------------------------------------------------
// Pointer Management
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk11
assign incremented_wr_ptr = wr_ptr + 1'b1;
assign incremented_rd_ptr = rd_ptr + 1'b1;
assign next_wr_ptr = drop_on_error ? curr_sop_ptr : write ? incremented_wr_ptr : wr_ptr;
assign next_rd_ptr = (read) ? incremented_rd_ptr : rd_ptr;
always @(posedge clk or posedge reset) begin
if (reset) begin
wr_ptr <= 0;
rd_ptr <= 0;
end
else begin
wr_ptr <= next_wr_ptr;
rd_ptr <= next_rd_ptr;
end
end
end else begin : gen_blk11_else
// --------------------------------------------------
// Shift Register Occupancy Bits
//
// Consider a 4-deep FIFO with 2 entries: 0011
// On a read and write, do not modify the bits.
// On a write, left-shift the bits to get 0111.
// On a read, right-shift the bits to get 0001.
//
// Also, on a write we set bit0 (the head), while
// clearing the tail on a read.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[0] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[0] <= 1;
else if (read) begin
if (DEPTH > 1)
mem_used[0] <= mem_used[1];
else
mem_used[0] <= 0;
end
end
end
end
if (DEPTH > 1) begin : gen_blk12
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[DEPTH-1] <= 0;
end
else begin
if (write ^ read) begin
mem_used[DEPTH-1] <= 0;
if (write)
mem_used[DEPTH-1] <= mem_used[DEPTH-2];
end
end
end
end
for (i = 1; i < DEPTH-1; i = i + 1) begin : storage_logic
always @(posedge clk, posedge reset) begin
if (reset) begin
mem_used[i] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[i] <= mem_used[i-1];
else if (read)
mem_used[i] <= mem_used[i+1];
end
end
end
end
end
endgenerate
// --------------------------------------------------
// Memory FIFO Status Management
//
// Generates the full and empty signals from the
// pointers. The FIFO is full when the next write
// pointer will be equal to the read pointer after
// a write. Reading from a FIFO clears full.
//
// The FIFO is empty when the next read pointer will
// be equal to the write pointer after a read. Writing
// to a FIFO clears empty.
//
// A simultaneous read and write must not change any of
// the empty or full flags unless there is a drop on error event.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk13
always @* begin
next_full = full;
next_empty = empty;
if (read && !write) begin
next_full = 1'b0;
if (incremented_rd_ptr == wr_ptr)
next_empty = 1'b1;
end
if (write && !read) begin
if (!drop_on_error)
next_empty = 1'b0;
else if (curr_sop_ptr == rd_ptr) // drop on error and only 1 pkt in fifo
next_empty = 1'b1;
if (incremented_wr_ptr == rd_ptr && !drop_on_error)
next_full = 1'b1;
end
if (write && read && drop_on_error) begin
if (curr_sop_ptr == next_rd_ptr)
next_empty = 1'b1;
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
empty <= 1;
full <= 0;
end
else begin
empty <= next_empty;
full <= next_full;
end
end
end else begin : gen_blk13_else
// --------------------------------------------------
// Register FIFO Status Management
//
// Full when the tail occupancy bit is 1. Empty when
// the head occupancy bit is 0.
// --------------------------------------------------
always @* begin
full = mem_used[DEPTH-1];
empty = !mem_used[0];
// ------------------------------------------
// For a single slot FIFO, reading clears the
// full status immediately.
// ------------------------------------------
if (DEPTH == 1)
full = mem_used[0] && !read;
internal_out_payload = mem[0];
// ------------------------------------------
// Writes clear empty immediately for lookahead modes.
// Note that we use in_valid instead of write to avoid
// combinational loops (in lookahead mode, qualifying
// with in_ready is meaningless).
//
// In a 1-deep FIFO, a possible combinational loop runs
// from write -> out_valid -> out_ready -> write
// ------------------------------------------
if (EMPTY_LATENCY == 0) begin
empty = !mem_used[0] && !in_valid;
if (!mem_used[0] && in_valid)
internal_out_payload = in_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Avalon-ST Signals
//
// The in_ready signal is straightforward.
//
// To match memory latency when empty latency > 1,
// out_valid assertions must be delayed by one clock
// cycle.
//
// Note: out_valid deassertions must not be delayed or
// the FIFO will underflow.
// --------------------------------------------------
assign in_ready = !full;
assign internal_out_ready = out_ready || !out_valid;
generate if (EMPTY_LATENCY > 1) begin : gen_blk14
always @(posedge clk or posedge reset) begin
if (reset)
internal_out_valid <= 0;
else begin
internal_out_valid <= !empty & ok_to_forward & ~drop_on_error;
if (read) begin
if (incremented_rd_ptr == wr_ptr)
internal_out_valid <= 1'b0;
end
end
end
end else begin : gen_blk14_else
always @* begin
internal_out_valid = !empty & ok_to_forward;
end
end
endgenerate
// --------------------------------------------------
// Single Output Pipeline Stage
//
// This output pipeline stage is enabled if the FIFO's
// empty latency is set to 3 (default). It is disabled
// for all other allowed latencies.
//
// Reason: The memory outputs are unregistered, so we have to
// register the output or fmax will drop if combinatorial
// logic is present on the output datapath.
//
// Q: The Avalon-ST spec says that I have to register my outputs
// But isn't the memory counted as a register?
// A: The path from the address lookup to the memory output is
// slow. Registering the memory outputs is a good idea.
//
// The registers get packed into the memory by the fitter
// which means minimal resources are consumed (the result
// is a altsyncram with registered outputs, available on
// all modern Altera devices).
//
// This output stage acts as an extra slot in the FIFO,
// and complicates the fill level.
// --------------------------------------------------
generate if (EMPTY_LATENCY == 3) begin : gen_blk15
always @(posedge clk or posedge reset) begin
if (reset) begin
out_valid <= 0;
out_payload <= 0;
end
else begin
if (internal_out_ready) begin
out_valid <= internal_out_valid & ok_to_forward;
out_payload <= internal_out_payload;
end
end
end
end
else begin : gen_blk15_else
always @* begin
out_valid = internal_out_valid;
out_payload = internal_out_payload;
end
end
endgenerate
// --------------------------------------------------
// Fill Level
//
// The fill level is calculated from the next write
// and read pointers to avoid unnecessary latency
// and logic.
//
// However, if the store-and-forward mode of the FIFO
// is enabled, the fill level is an up-down counter
// for fmax optimization reasons.
//
// If the output pipeline is enabled, the fill level
// must account for it, or we'll always be off by one.
// This may, or may not be important depending on the
// application.
//
// For now, we'll always calculate the exact fill level
// at the cost of an extra adder when the output stage
// is enabled.
// --------------------------------------------------
generate if (USE_FILL_LEVEL) begin : gen_blk16
wire [31:0] depth32;
assign depth32 = DEPTH;
if (USE_STORE_FORWARD) begin
reg [ADDR_WIDTH : 0] curr_packet_len_less_one;
// --------------------------------------------------
// We only drop on endofpacket. As long as we don't add to the fill
// level on the dropped endofpacket cycle, we can simply subtract
// (packet length - 1) from the fill level for dropped packets.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
curr_packet_len_less_one <= 0;
end else begin
if (write) begin
curr_packet_len_less_one <= curr_packet_len_less_one + 1'b1;
if (in_endofpacket)
curr_packet_len_less_one <= 0;
end
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
fifo_fill_level <= 0;
end else if (drop_on_error) begin
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one;
if (read)
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one - 1'b1;
end else if (write && !read) begin
fifo_fill_level <= fifo_fill_level + 1'b1;
end else if (read && !write) begin
fifo_fill_level <= fifo_fill_level - 1'b1;
end
end
end else begin
always @(posedge clk or posedge reset) begin
if (reset)
fifo_fill_level <= 0;
else if (next_full & !drop_on_error)
fifo_fill_level <= depth32[ADDR_WIDTH:0];
else begin
fifo_fill_level[ADDR_WIDTH] <= 1'b0;
fifo_fill_level[ADDR_WIDTH-1 : 0] <= next_wr_ptr - next_rd_ptr;
end
end
end
always @* begin
fill_level = fifo_fill_level;
if (EMPTY_LATENCY == 3)
fill_level = fifo_fill_level + {{ADDR_WIDTH{1'b0}}, out_valid};
end
end
else begin : gen_blk16_else
always @* begin
fill_level = 0;
end
end
endgenerate
generate if (USE_ALMOST_FULL_IF) begin : gen_blk17
assign almost_full_data = (fill_level >= almost_full_threshold);
end
else
assign almost_full_data = 0;
endgenerate
generate if (USE_ALMOST_EMPTY_IF) begin : gen_blk18
assign almost_empty_data = (fill_level <= almost_empty_threshold);
end
else
assign almost_empty_data = 0;
endgenerate
// --------------------------------------------------
// Avalon-MM Status & Control Connection Point
//
// Register map:
//
// | Addr | RW | 31 - 0 |
// | 0 | R | Fill level |
//
// The registering of this connection point means
// that there is a cycle of latency between
// reads/writes and the updating of the fill level.
// --------------------------------------------------
generate if (USE_STORE_FORWARD) begin : gen_blk19
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
cut_through_threshold <= 0;
drop_on_error_en <= 0;
csr_readdata <= 0;
pkt_mode <= 1'b1;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 5)
csr_readdata <= {31'b0, drop_on_error_en};
else if (csr_address == 4)
csr_readdata <= {8'b0, cut_through_threshold};
else if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b101)
drop_on_error_en <= csr_writedata[0];
else if(csr_address == 3'b100) begin
cut_through_threshold <= csr_writedata[23:0];
pkt_mode <= (csr_writedata[23:0] == 0);
end
else if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else if (USE_ALMOST_FULL_IF || USE_ALMOST_EMPTY_IF) begin : gen_blk19_else1
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
csr_readdata <= 0;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else begin : gen_blk19_else2
always @(posedge clk or posedge reset) begin
if (reset) begin
csr_readdata <= 0;
end
else if (csr_read) begin
csr_readdata <= 0;
if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
end
end
endgenerate
// --------------------------------------------------
// Store and forward logic
// --------------------------------------------------
// if the fifo gets full before the entire packet or the
// cut-threshold condition is met then start sending out
// data in order to avoid dead-lock situation
generate if (USE_STORE_FORWARD) begin : gen_blk20
assign wait_for_threshold = (fifo_fill_level_lt_cut_through_threshold) & wait_for_pkt ;
assign wait_for_pkt = pkt_cnt_eq_zero | (pkt_cnt_eq_one & out_pkt_leave);
assign ok_to_forward = (pkt_mode ? (~wait_for_pkt | ~pkt_has_started) :
~wait_for_threshold) | fifo_too_small_r;
assign in_pkt_eop_arrive = in_valid & in_ready & in_endofpacket;
assign in_pkt_start = in_valid & in_ready & in_startofpacket;
assign in_pkt_error = in_valid & in_ready & |in_error;
assign out_pkt_sop_leave = out_valid & out_ready & out_startofpacket;
assign out_pkt_leave = out_valid & out_ready & out_endofpacket;
assign fifo_too_small = (pkt_mode ? wait_for_pkt : wait_for_threshold) & full & out_ready;
// count packets coming and going into the fifo
always @(posedge clk or posedge reset) begin
if (reset) begin
pkt_cnt <= 0;
pkt_has_started <= 0;
sop_has_left_fifo <= 0;
fifo_too_small_r <= 0;
pkt_cnt_eq_zero <= 1'b1;
pkt_cnt_eq_one <= 1'b0;
fifo_fill_level_lt_cut_through_threshold <= 1'b1;
end
else begin
fifo_fill_level_lt_cut_through_threshold <= fifo_fill_level < cut_through_threshold;
fifo_too_small_r <= fifo_too_small;
if( in_pkt_eop_arrive )
sop_has_left_fifo <= 1'b0;
else if (out_pkt_sop_leave & pkt_cnt_eq_zero )
sop_has_left_fifo <= 1'b1;
if (in_pkt_eop_arrive & ~out_pkt_leave & ~drop_on_error ) begin
pkt_cnt <= pkt_cnt + 1'b1;
pkt_cnt_eq_zero <= 0;
if (pkt_cnt == 0)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
else if((~in_pkt_eop_arrive | drop_on_error) & out_pkt_leave) begin
pkt_cnt <= pkt_cnt - 1'b1;
if (pkt_cnt == 1)
pkt_cnt_eq_zero <= 1'b1;
else
pkt_cnt_eq_zero <= 1'b0;
if (pkt_cnt == 2)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
if (in_pkt_start)
pkt_has_started <= 1'b1;
else if (in_pkt_eop_arrive)
pkt_has_started <= 1'b0;
end
end
// drop on error logic
always @(posedge clk or posedge reset) begin
if (reset) begin
sop_ptr <= 0;
error_in_pkt <= 0;
end
else begin
// save the location of the SOP
if ( in_pkt_start )
sop_ptr <= wr_ptr;
// remember if error in pkt
// log error only if packet has already started
if (in_pkt_eop_arrive)
error_in_pkt <= 1'b0;
else if ( in_pkt_error & (pkt_has_started | in_pkt_start))
error_in_pkt <= 1'b1;
end
end
assign drop_on_error = drop_on_error_en & (error_in_pkt | in_pkt_error) & in_pkt_eop_arrive &
~sop_has_left_fifo & ~(out_pkt_sop_leave & pkt_cnt_eq_zero);
assign curr_sop_ptr = (write && in_startofpacket && in_endofpacket) ? wr_ptr : sop_ptr;
end
else begin : gen_blk20_else
assign ok_to_forward = 1'b1;
assign drop_on_error = 1'b0;
if (ADDR_WIDTH <= 1)
assign curr_sop_ptr = 1'b0;
else
assign curr_sop_ptr = {ADDR_WIDTH - 1 { 1'b0 }};
end
endgenerate
// --------------------------------------------------
// Calculates the log2ceil of the input value
// --------------------------------------------------
function integer log2ceil;
input integer val;
reg[31:0] i;
begin
i = 1;
log2ceil = 0;
while (i < val) begin
log2ceil = log2ceil + 1;
i = i[30:0] << 1;
end
end
endfunction
endmodule |
module altera_avalon_sc_fifo
#(
// --------------------------------------------------
// Parameters
// --------------------------------------------------
parameter SYMBOLS_PER_BEAT = 1,
parameter BITS_PER_SYMBOL = 8,
parameter FIFO_DEPTH = 16,
parameter CHANNEL_WIDTH = 0,
parameter ERROR_WIDTH = 0,
parameter USE_PACKETS = 0,
parameter USE_FILL_LEVEL = 0,
parameter USE_STORE_FORWARD = 0,
parameter USE_ALMOST_FULL_IF = 0,
parameter USE_ALMOST_EMPTY_IF = 0,
// --------------------------------------------------
// Empty latency is defined as the number of cycles
// required for a write to deassert the empty flag.
// For example, a latency of 1 means that the empty
// flag is deasserted on the cycle after a write.
//
// Another way to think of it is the latency for a
// write to propagate to the output.
//
// An empty latency of 0 implies lookahead, which is
// only implemented for the register-based FIFO.
// --------------------------------------------------
parameter EMPTY_LATENCY = 3,
parameter USE_MEMORY_BLOCKS = 1,
// --------------------------------------------------
// Internal Parameters
// --------------------------------------------------
parameter DATA_WIDTH = SYMBOLS_PER_BEAT * BITS_PER_SYMBOL,
parameter EMPTY_WIDTH = log2ceil(SYMBOLS_PER_BEAT)
)
(
// --------------------------------------------------
// Ports
// --------------------------------------------------
input clk,
input reset,
input [DATA_WIDTH-1: 0] in_data,
input in_valid,
input in_startofpacket,
input in_endofpacket,
input [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] in_empty,
input [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] in_error,
input [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] in_channel,
output in_ready,
output [DATA_WIDTH-1 : 0] out_data,
output reg out_valid,
output out_startofpacket,
output out_endofpacket,
output [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] out_empty,
output [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] out_error,
output [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] out_channel,
input out_ready,
input [(USE_STORE_FORWARD ? 2 : 1) : 0] csr_address,
input csr_write,
input csr_read,
input [31 : 0] csr_writedata,
output reg [31 : 0] csr_readdata,
output wire almost_full_data,
output wire almost_empty_data
);
// --------------------------------------------------
// Local Parameters
// --------------------------------------------------
localparam ADDR_WIDTH = log2ceil(FIFO_DEPTH);
localparam DEPTH = FIFO_DEPTH;
localparam PKT_SIGNALS_WIDTH = 2 + EMPTY_WIDTH;
localparam PAYLOAD_WIDTH = (USE_PACKETS == 1) ?
2 + EMPTY_WIDTH + DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH:
DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH;
// --------------------------------------------------
// Internal Signals
// --------------------------------------------------
genvar i;
reg [PAYLOAD_WIDTH-1 : 0] mem [DEPTH-1 : 0];
reg [ADDR_WIDTH-1 : 0] wr_ptr;
reg [ADDR_WIDTH-1 : 0] rd_ptr;
reg [DEPTH-1 : 0] mem_used;
wire [ADDR_WIDTH-1 : 0] next_wr_ptr;
wire [ADDR_WIDTH-1 : 0] next_rd_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_wr_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_rd_ptr;
wire [ADDR_WIDTH-1 : 0] mem_rd_ptr;
wire read;
wire write;
reg empty;
reg next_empty;
reg full;
reg next_full;
wire [PKT_SIGNALS_WIDTH-1 : 0] in_packet_signals;
wire [PKT_SIGNALS_WIDTH-1 : 0] out_packet_signals;
wire [PAYLOAD_WIDTH-1 : 0] in_payload;
reg [PAYLOAD_WIDTH-1 : 0] internal_out_payload;
reg [PAYLOAD_WIDTH-1 : 0] out_payload;
reg internal_out_valid;
wire internal_out_ready;
reg [ADDR_WIDTH : 0] fifo_fill_level;
reg [ADDR_WIDTH : 0] fill_level;
reg [ADDR_WIDTH-1 : 0] sop_ptr = 0;
wire [ADDR_WIDTH-1 : 0] curr_sop_ptr;
reg [23:0] almost_full_threshold;
reg [23:0] almost_empty_threshold;
reg [23:0] cut_through_threshold;
reg [15:0] pkt_cnt;
reg drop_on_error_en;
reg error_in_pkt;
reg pkt_has_started;
reg sop_has_left_fifo;
reg fifo_too_small_r;
reg pkt_cnt_eq_zero;
reg pkt_cnt_eq_one;
wire wait_for_threshold;
reg pkt_mode;
wire wait_for_pkt;
wire ok_to_forward;
wire in_pkt_eop_arrive;
wire out_pkt_leave;
wire in_pkt_start;
wire in_pkt_error;
wire drop_on_error;
wire fifo_too_small;
wire out_pkt_sop_leave;
wire [31:0] max_fifo_size;
reg fifo_fill_level_lt_cut_through_threshold;
// --------------------------------------------------
// Define Payload
//
// Icky part where we decide which signals form the
// payload to the FIFO with generate blocks.
// --------------------------------------------------
generate
if (EMPTY_WIDTH > 0) begin : gen_blk1
assign in_packet_signals = {in_startofpacket, in_endofpacket, in_empty};
assign {out_startofpacket, out_endofpacket, out_empty} = out_packet_signals;
end
else begin : gen_blk1_else
assign out_empty = in_error;
assign in_packet_signals = {in_startofpacket, in_endofpacket};
assign {out_startofpacket, out_endofpacket} = out_packet_signals;
end
endgenerate
generate
if (USE_PACKETS) begin : gen_blk2
if (ERROR_WIDTH > 0) begin : gen_blk3
if (CHANNEL_WIDTH > 0) begin : gen_blk4
assign in_payload = {in_packet_signals, in_data, in_error, in_channel};
assign {out_packet_signals, out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk4_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data, in_error};
assign {out_packet_signals, out_data, out_error} = out_payload;
end
end
else begin : gen_blk3_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk5
assign in_payload = {in_packet_signals, in_data, in_channel};
assign {out_packet_signals, out_data, out_channel} = out_payload;
end
else begin : gen_blk5_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data};
assign {out_packet_signals, out_data} = out_payload;
end
end
end
else begin : gen_blk2_else
assign out_packet_signals = 0;
if (ERROR_WIDTH > 0) begin : gen_blk6
if (CHANNEL_WIDTH > 0) begin : gen_blk7
assign in_payload = {in_data, in_error, in_channel};
assign {out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk7_else
assign out_channel = in_channel;
assign in_payload = {in_data, in_error};
assign {out_data, out_error} = out_payload;
end
end
else begin : gen_blk6_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk8
assign in_payload = {in_data, in_channel};
assign {out_data, out_channel} = out_payload;
end
else begin : gen_blk8_else
assign out_channel = in_channel;
assign in_payload = in_data;
assign out_data = out_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Memory-based FIFO storage
//
// To allow a ready latency of 0, the read index is
// obtained from the next read pointer and memory
// outputs are unregistered.
//
// If the empty latency is 1, we infer bypass logic
// around the memory so writes propagate to the
// outputs on the next cycle.
//
// Do not change the way this is coded: Quartus needs
// a perfect match to the template, and any attempt to
// refactor the two always blocks into one will break
// memory inference.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk9
if (EMPTY_LATENCY == 1) begin : gen_blk10
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] = in_payload;
internal_out_payload = mem[mem_rd_ptr];
end
end else begin : gen_blk10_else
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] <= in_payload;
internal_out_payload <= mem[mem_rd_ptr];
end
end
assign mem_rd_ptr = next_rd_ptr;
end else begin : gen_blk9_else
// --------------------------------------------------
// Register-based FIFO storage
//
// Uses a shift register as the storage element. Each
// shift register slot has a bit which indicates if
// the slot is occupied (credit to Sam H for the idea).
// The occupancy bits are contiguous and start from the
// lsb, so 0000, 0001, 0011, 0111, 1111 for a 4-deep
// FIFO.
//
// Each slot is enabled during a read or when it
// is unoccupied. New data is always written to every
// going-to-be-empty slot (we keep track of which ones
// are actually useful with the occupancy bits). On a
// read we shift occupied slots.
//
// The exception is the last slot, which always gets
// new data when it is unoccupied.
// --------------------------------------------------
for (i = 0; i < DEPTH-1; i = i + 1) begin : shift_reg
always @(posedge clk or posedge reset) begin
if (reset) begin
mem[i] <= 0;
end
else if (read || !mem_used[i]) begin
if (!mem_used[i+1])
mem[i] <= in_payload;
else
mem[i] <= mem[i+1];
end
end
end
always @(posedge clk, posedge reset) begin
if (reset) begin
mem[DEPTH-1] <= 0;
end
else begin
if (DEPTH == 1) begin
if (write)
mem[DEPTH-1] <= in_payload;
end
else if (!mem_used[DEPTH-1])
mem[DEPTH-1] <= in_payload;
end
end
end
endgenerate
assign read = internal_out_ready && internal_out_valid && ok_to_forward;
assign write = in_ready && in_valid;
// --------------------------------------------------
// Pointer Management
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk11
assign incremented_wr_ptr = wr_ptr + 1'b1;
assign incremented_rd_ptr = rd_ptr + 1'b1;
assign next_wr_ptr = drop_on_error ? curr_sop_ptr : write ? incremented_wr_ptr : wr_ptr;
assign next_rd_ptr = (read) ? incremented_rd_ptr : rd_ptr;
always @(posedge clk or posedge reset) begin
if (reset) begin
wr_ptr <= 0;
rd_ptr <= 0;
end
else begin
wr_ptr <= next_wr_ptr;
rd_ptr <= next_rd_ptr;
end
end
end else begin : gen_blk11_else
// --------------------------------------------------
// Shift Register Occupancy Bits
//
// Consider a 4-deep FIFO with 2 entries: 0011
// On a read and write, do not modify the bits.
// On a write, left-shift the bits to get 0111.
// On a read, right-shift the bits to get 0001.
//
// Also, on a write we set bit0 (the head), while
// clearing the tail on a read.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[0] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[0] <= 1;
else if (read) begin
if (DEPTH > 1)
mem_used[0] <= mem_used[1];
else
mem_used[0] <= 0;
end
end
end
end
if (DEPTH > 1) begin : gen_blk12
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[DEPTH-1] <= 0;
end
else begin
if (write ^ read) begin
mem_used[DEPTH-1] <= 0;
if (write)
mem_used[DEPTH-1] <= mem_used[DEPTH-2];
end
end
end
end
for (i = 1; i < DEPTH-1; i = i + 1) begin : storage_logic
always @(posedge clk, posedge reset) begin
if (reset) begin
mem_used[i] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[i] <= mem_used[i-1];
else if (read)
mem_used[i] <= mem_used[i+1];
end
end
end
end
end
endgenerate
// --------------------------------------------------
// Memory FIFO Status Management
//
// Generates the full and empty signals from the
// pointers. The FIFO is full when the next write
// pointer will be equal to the read pointer after
// a write. Reading from a FIFO clears full.
//
// The FIFO is empty when the next read pointer will
// be equal to the write pointer after a read. Writing
// to a FIFO clears empty.
//
// A simultaneous read and write must not change any of
// the empty or full flags unless there is a drop on error event.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk13
always @* begin
next_full = full;
next_empty = empty;
if (read && !write) begin
next_full = 1'b0;
if (incremented_rd_ptr == wr_ptr)
next_empty = 1'b1;
end
if (write && !read) begin
if (!drop_on_error)
next_empty = 1'b0;
else if (curr_sop_ptr == rd_ptr) // drop on error and only 1 pkt in fifo
next_empty = 1'b1;
if (incremented_wr_ptr == rd_ptr && !drop_on_error)
next_full = 1'b1;
end
if (write && read && drop_on_error) begin
if (curr_sop_ptr == next_rd_ptr)
next_empty = 1'b1;
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
empty <= 1;
full <= 0;
end
else begin
empty <= next_empty;
full <= next_full;
end
end
end else begin : gen_blk13_else
// --------------------------------------------------
// Register FIFO Status Management
//
// Full when the tail occupancy bit is 1. Empty when
// the head occupancy bit is 0.
// --------------------------------------------------
always @* begin
full = mem_used[DEPTH-1];
empty = !mem_used[0];
// ------------------------------------------
// For a single slot FIFO, reading clears the
// full status immediately.
// ------------------------------------------
if (DEPTH == 1)
full = mem_used[0] && !read;
internal_out_payload = mem[0];
// ------------------------------------------
// Writes clear empty immediately for lookahead modes.
// Note that we use in_valid instead of write to avoid
// combinational loops (in lookahead mode, qualifying
// with in_ready is meaningless).
//
// In a 1-deep FIFO, a possible combinational loop runs
// from write -> out_valid -> out_ready -> write
// ------------------------------------------
if (EMPTY_LATENCY == 0) begin
empty = !mem_used[0] && !in_valid;
if (!mem_used[0] && in_valid)
internal_out_payload = in_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Avalon-ST Signals
//
// The in_ready signal is straightforward.
//
// To match memory latency when empty latency > 1,
// out_valid assertions must be delayed by one clock
// cycle.
//
// Note: out_valid deassertions must not be delayed or
// the FIFO will underflow.
// --------------------------------------------------
assign in_ready = !full;
assign internal_out_ready = out_ready || !out_valid;
generate if (EMPTY_LATENCY > 1) begin : gen_blk14
always @(posedge clk or posedge reset) begin
if (reset)
internal_out_valid <= 0;
else begin
internal_out_valid <= !empty & ok_to_forward & ~drop_on_error;
if (read) begin
if (incremented_rd_ptr == wr_ptr)
internal_out_valid <= 1'b0;
end
end
end
end else begin : gen_blk14_else
always @* begin
internal_out_valid = !empty & ok_to_forward;
end
end
endgenerate
// --------------------------------------------------
// Single Output Pipeline Stage
//
// This output pipeline stage is enabled if the FIFO's
// empty latency is set to 3 (default). It is disabled
// for all other allowed latencies.
//
// Reason: The memory outputs are unregistered, so we have to
// register the output or fmax will drop if combinatorial
// logic is present on the output datapath.
//
// Q: The Avalon-ST spec says that I have to register my outputs
// But isn't the memory counted as a register?
// A: The path from the address lookup to the memory output is
// slow. Registering the memory outputs is a good idea.
//
// The registers get packed into the memory by the fitter
// which means minimal resources are consumed (the result
// is a altsyncram with registered outputs, available on
// all modern Altera devices).
//
// This output stage acts as an extra slot in the FIFO,
// and complicates the fill level.
// --------------------------------------------------
generate if (EMPTY_LATENCY == 3) begin : gen_blk15
always @(posedge clk or posedge reset) begin
if (reset) begin
out_valid <= 0;
out_payload <= 0;
end
else begin
if (internal_out_ready) begin
out_valid <= internal_out_valid & ok_to_forward;
out_payload <= internal_out_payload;
end
end
end
end
else begin : gen_blk15_else
always @* begin
out_valid = internal_out_valid;
out_payload = internal_out_payload;
end
end
endgenerate
// --------------------------------------------------
// Fill Level
//
// The fill level is calculated from the next write
// and read pointers to avoid unnecessary latency
// and logic.
//
// However, if the store-and-forward mode of the FIFO
// is enabled, the fill level is an up-down counter
// for fmax optimization reasons.
//
// If the output pipeline is enabled, the fill level
// must account for it, or we'll always be off by one.
// This may, or may not be important depending on the
// application.
//
// For now, we'll always calculate the exact fill level
// at the cost of an extra adder when the output stage
// is enabled.
// --------------------------------------------------
generate if (USE_FILL_LEVEL) begin : gen_blk16
wire [31:0] depth32;
assign depth32 = DEPTH;
if (USE_STORE_FORWARD) begin
reg [ADDR_WIDTH : 0] curr_packet_len_less_one;
// --------------------------------------------------
// We only drop on endofpacket. As long as we don't add to the fill
// level on the dropped endofpacket cycle, we can simply subtract
// (packet length - 1) from the fill level for dropped packets.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
curr_packet_len_less_one <= 0;
end else begin
if (write) begin
curr_packet_len_less_one <= curr_packet_len_less_one + 1'b1;
if (in_endofpacket)
curr_packet_len_less_one <= 0;
end
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
fifo_fill_level <= 0;
end else if (drop_on_error) begin
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one;
if (read)
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one - 1'b1;
end else if (write && !read) begin
fifo_fill_level <= fifo_fill_level + 1'b1;
end else if (read && !write) begin
fifo_fill_level <= fifo_fill_level - 1'b1;
end
end
end else begin
always @(posedge clk or posedge reset) begin
if (reset)
fifo_fill_level <= 0;
else if (next_full & !drop_on_error)
fifo_fill_level <= depth32[ADDR_WIDTH:0];
else begin
fifo_fill_level[ADDR_WIDTH] <= 1'b0;
fifo_fill_level[ADDR_WIDTH-1 : 0] <= next_wr_ptr - next_rd_ptr;
end
end
end
always @* begin
fill_level = fifo_fill_level;
if (EMPTY_LATENCY == 3)
fill_level = fifo_fill_level + {{ADDR_WIDTH{1'b0}}, out_valid};
end
end
else begin : gen_blk16_else
always @* begin
fill_level = 0;
end
end
endgenerate
generate if (USE_ALMOST_FULL_IF) begin : gen_blk17
assign almost_full_data = (fill_level >= almost_full_threshold);
end
else
assign almost_full_data = 0;
endgenerate
generate if (USE_ALMOST_EMPTY_IF) begin : gen_blk18
assign almost_empty_data = (fill_level <= almost_empty_threshold);
end
else
assign almost_empty_data = 0;
endgenerate
// --------------------------------------------------
// Avalon-MM Status & Control Connection Point
//
// Register map:
//
// | Addr | RW | 31 - 0 |
// | 0 | R | Fill level |
//
// The registering of this connection point means
// that there is a cycle of latency between
// reads/writes and the updating of the fill level.
// --------------------------------------------------
generate if (USE_STORE_FORWARD) begin : gen_blk19
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
cut_through_threshold <= 0;
drop_on_error_en <= 0;
csr_readdata <= 0;
pkt_mode <= 1'b1;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 5)
csr_readdata <= {31'b0, drop_on_error_en};
else if (csr_address == 4)
csr_readdata <= {8'b0, cut_through_threshold};
else if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b101)
drop_on_error_en <= csr_writedata[0];
else if(csr_address == 3'b100) begin
cut_through_threshold <= csr_writedata[23:0];
pkt_mode <= (csr_writedata[23:0] == 0);
end
else if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else if (USE_ALMOST_FULL_IF || USE_ALMOST_EMPTY_IF) begin : gen_blk19_else1
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
csr_readdata <= 0;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else begin : gen_blk19_else2
always @(posedge clk or posedge reset) begin
if (reset) begin
csr_readdata <= 0;
end
else if (csr_read) begin
csr_readdata <= 0;
if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
end
end
endgenerate
// --------------------------------------------------
// Store and forward logic
// --------------------------------------------------
// if the fifo gets full before the entire packet or the
// cut-threshold condition is met then start sending out
// data in order to avoid dead-lock situation
generate if (USE_STORE_FORWARD) begin : gen_blk20
assign wait_for_threshold = (fifo_fill_level_lt_cut_through_threshold) & wait_for_pkt ;
assign wait_for_pkt = pkt_cnt_eq_zero | (pkt_cnt_eq_one & out_pkt_leave);
assign ok_to_forward = (pkt_mode ? (~wait_for_pkt | ~pkt_has_started) :
~wait_for_threshold) | fifo_too_small_r;
assign in_pkt_eop_arrive = in_valid & in_ready & in_endofpacket;
assign in_pkt_start = in_valid & in_ready & in_startofpacket;
assign in_pkt_error = in_valid & in_ready & |in_error;
assign out_pkt_sop_leave = out_valid & out_ready & out_startofpacket;
assign out_pkt_leave = out_valid & out_ready & out_endofpacket;
assign fifo_too_small = (pkt_mode ? wait_for_pkt : wait_for_threshold) & full & out_ready;
// count packets coming and going into the fifo
always @(posedge clk or posedge reset) begin
if (reset) begin
pkt_cnt <= 0;
pkt_has_started <= 0;
sop_has_left_fifo <= 0;
fifo_too_small_r <= 0;
pkt_cnt_eq_zero <= 1'b1;
pkt_cnt_eq_one <= 1'b0;
fifo_fill_level_lt_cut_through_threshold <= 1'b1;
end
else begin
fifo_fill_level_lt_cut_through_threshold <= fifo_fill_level < cut_through_threshold;
fifo_too_small_r <= fifo_too_small;
if( in_pkt_eop_arrive )
sop_has_left_fifo <= 1'b0;
else if (out_pkt_sop_leave & pkt_cnt_eq_zero )
sop_has_left_fifo <= 1'b1;
if (in_pkt_eop_arrive & ~out_pkt_leave & ~drop_on_error ) begin
pkt_cnt <= pkt_cnt + 1'b1;
pkt_cnt_eq_zero <= 0;
if (pkt_cnt == 0)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
else if((~in_pkt_eop_arrive | drop_on_error) & out_pkt_leave) begin
pkt_cnt <= pkt_cnt - 1'b1;
if (pkt_cnt == 1)
pkt_cnt_eq_zero <= 1'b1;
else
pkt_cnt_eq_zero <= 1'b0;
if (pkt_cnt == 2)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
if (in_pkt_start)
pkt_has_started <= 1'b1;
else if (in_pkt_eop_arrive)
pkt_has_started <= 1'b0;
end
end
// drop on error logic
always @(posedge clk or posedge reset) begin
if (reset) begin
sop_ptr <= 0;
error_in_pkt <= 0;
end
else begin
// save the location of the SOP
if ( in_pkt_start )
sop_ptr <= wr_ptr;
// remember if error in pkt
// log error only if packet has already started
if (in_pkt_eop_arrive)
error_in_pkt <= 1'b0;
else if ( in_pkt_error & (pkt_has_started | in_pkt_start))
error_in_pkt <= 1'b1;
end
end
assign drop_on_error = drop_on_error_en & (error_in_pkt | in_pkt_error) & in_pkt_eop_arrive &
~sop_has_left_fifo & ~(out_pkt_sop_leave & pkt_cnt_eq_zero);
assign curr_sop_ptr = (write && in_startofpacket && in_endofpacket) ? wr_ptr : sop_ptr;
end
else begin : gen_blk20_else
assign ok_to_forward = 1'b1;
assign drop_on_error = 1'b0;
if (ADDR_WIDTH <= 1)
assign curr_sop_ptr = 1'b0;
else
assign curr_sop_ptr = {ADDR_WIDTH - 1 { 1'b0 }};
end
endgenerate
// --------------------------------------------------
// Calculates the log2ceil of the input value
// --------------------------------------------------
function integer log2ceil;
input integer val;
reg[31:0] i;
begin
i = 1;
log2ceil = 0;
while (i < val) begin
log2ceil = log2ceil + 1;
i = i[30:0] << 1;
end
end
endfunction
endmodule |
module altera_avalon_sc_fifo
#(
// --------------------------------------------------
// Parameters
// --------------------------------------------------
parameter SYMBOLS_PER_BEAT = 1,
parameter BITS_PER_SYMBOL = 8,
parameter FIFO_DEPTH = 16,
parameter CHANNEL_WIDTH = 0,
parameter ERROR_WIDTH = 0,
parameter USE_PACKETS = 0,
parameter USE_FILL_LEVEL = 0,
parameter USE_STORE_FORWARD = 0,
parameter USE_ALMOST_FULL_IF = 0,
parameter USE_ALMOST_EMPTY_IF = 0,
// --------------------------------------------------
// Empty latency is defined as the number of cycles
// required for a write to deassert the empty flag.
// For example, a latency of 1 means that the empty
// flag is deasserted on the cycle after a write.
//
// Another way to think of it is the latency for a
// write to propagate to the output.
//
// An empty latency of 0 implies lookahead, which is
// only implemented for the register-based FIFO.
// --------------------------------------------------
parameter EMPTY_LATENCY = 3,
parameter USE_MEMORY_BLOCKS = 1,
// --------------------------------------------------
// Internal Parameters
// --------------------------------------------------
parameter DATA_WIDTH = SYMBOLS_PER_BEAT * BITS_PER_SYMBOL,
parameter EMPTY_WIDTH = log2ceil(SYMBOLS_PER_BEAT)
)
(
// --------------------------------------------------
// Ports
// --------------------------------------------------
input clk,
input reset,
input [DATA_WIDTH-1: 0] in_data,
input in_valid,
input in_startofpacket,
input in_endofpacket,
input [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] in_empty,
input [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] in_error,
input [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] in_channel,
output in_ready,
output [DATA_WIDTH-1 : 0] out_data,
output reg out_valid,
output out_startofpacket,
output out_endofpacket,
output [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] out_empty,
output [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] out_error,
output [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] out_channel,
input out_ready,
input [(USE_STORE_FORWARD ? 2 : 1) : 0] csr_address,
input csr_write,
input csr_read,
input [31 : 0] csr_writedata,
output reg [31 : 0] csr_readdata,
output wire almost_full_data,
output wire almost_empty_data
);
// --------------------------------------------------
// Local Parameters
// --------------------------------------------------
localparam ADDR_WIDTH = log2ceil(FIFO_DEPTH);
localparam DEPTH = FIFO_DEPTH;
localparam PKT_SIGNALS_WIDTH = 2 + EMPTY_WIDTH;
localparam PAYLOAD_WIDTH = (USE_PACKETS == 1) ?
2 + EMPTY_WIDTH + DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH:
DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH;
// --------------------------------------------------
// Internal Signals
// --------------------------------------------------
genvar i;
reg [PAYLOAD_WIDTH-1 : 0] mem [DEPTH-1 : 0];
reg [ADDR_WIDTH-1 : 0] wr_ptr;
reg [ADDR_WIDTH-1 : 0] rd_ptr;
reg [DEPTH-1 : 0] mem_used;
wire [ADDR_WIDTH-1 : 0] next_wr_ptr;
wire [ADDR_WIDTH-1 : 0] next_rd_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_wr_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_rd_ptr;
wire [ADDR_WIDTH-1 : 0] mem_rd_ptr;
wire read;
wire write;
reg empty;
reg next_empty;
reg full;
reg next_full;
wire [PKT_SIGNALS_WIDTH-1 : 0] in_packet_signals;
wire [PKT_SIGNALS_WIDTH-1 : 0] out_packet_signals;
wire [PAYLOAD_WIDTH-1 : 0] in_payload;
reg [PAYLOAD_WIDTH-1 : 0] internal_out_payload;
reg [PAYLOAD_WIDTH-1 : 0] out_payload;
reg internal_out_valid;
wire internal_out_ready;
reg [ADDR_WIDTH : 0] fifo_fill_level;
reg [ADDR_WIDTH : 0] fill_level;
reg [ADDR_WIDTH-1 : 0] sop_ptr = 0;
wire [ADDR_WIDTH-1 : 0] curr_sop_ptr;
reg [23:0] almost_full_threshold;
reg [23:0] almost_empty_threshold;
reg [23:0] cut_through_threshold;
reg [15:0] pkt_cnt;
reg drop_on_error_en;
reg error_in_pkt;
reg pkt_has_started;
reg sop_has_left_fifo;
reg fifo_too_small_r;
reg pkt_cnt_eq_zero;
reg pkt_cnt_eq_one;
wire wait_for_threshold;
reg pkt_mode;
wire wait_for_pkt;
wire ok_to_forward;
wire in_pkt_eop_arrive;
wire out_pkt_leave;
wire in_pkt_start;
wire in_pkt_error;
wire drop_on_error;
wire fifo_too_small;
wire out_pkt_sop_leave;
wire [31:0] max_fifo_size;
reg fifo_fill_level_lt_cut_through_threshold;
// --------------------------------------------------
// Define Payload
//
// Icky part where we decide which signals form the
// payload to the FIFO with generate blocks.
// --------------------------------------------------
generate
if (EMPTY_WIDTH > 0) begin : gen_blk1
assign in_packet_signals = {in_startofpacket, in_endofpacket, in_empty};
assign {out_startofpacket, out_endofpacket, out_empty} = out_packet_signals;
end
else begin : gen_blk1_else
assign out_empty = in_error;
assign in_packet_signals = {in_startofpacket, in_endofpacket};
assign {out_startofpacket, out_endofpacket} = out_packet_signals;
end
endgenerate
generate
if (USE_PACKETS) begin : gen_blk2
if (ERROR_WIDTH > 0) begin : gen_blk3
if (CHANNEL_WIDTH > 0) begin : gen_blk4
assign in_payload = {in_packet_signals, in_data, in_error, in_channel};
assign {out_packet_signals, out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk4_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data, in_error};
assign {out_packet_signals, out_data, out_error} = out_payload;
end
end
else begin : gen_blk3_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk5
assign in_payload = {in_packet_signals, in_data, in_channel};
assign {out_packet_signals, out_data, out_channel} = out_payload;
end
else begin : gen_blk5_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data};
assign {out_packet_signals, out_data} = out_payload;
end
end
end
else begin : gen_blk2_else
assign out_packet_signals = 0;
if (ERROR_WIDTH > 0) begin : gen_blk6
if (CHANNEL_WIDTH > 0) begin : gen_blk7
assign in_payload = {in_data, in_error, in_channel};
assign {out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk7_else
assign out_channel = in_channel;
assign in_payload = {in_data, in_error};
assign {out_data, out_error} = out_payload;
end
end
else begin : gen_blk6_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk8
assign in_payload = {in_data, in_channel};
assign {out_data, out_channel} = out_payload;
end
else begin : gen_blk8_else
assign out_channel = in_channel;
assign in_payload = in_data;
assign out_data = out_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Memory-based FIFO storage
//
// To allow a ready latency of 0, the read index is
// obtained from the next read pointer and memory
// outputs are unregistered.
//
// If the empty latency is 1, we infer bypass logic
// around the memory so writes propagate to the
// outputs on the next cycle.
//
// Do not change the way this is coded: Quartus needs
// a perfect match to the template, and any attempt to
// refactor the two always blocks into one will break
// memory inference.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk9
if (EMPTY_LATENCY == 1) begin : gen_blk10
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] = in_payload;
internal_out_payload = mem[mem_rd_ptr];
end
end else begin : gen_blk10_else
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] <= in_payload;
internal_out_payload <= mem[mem_rd_ptr];
end
end
assign mem_rd_ptr = next_rd_ptr;
end else begin : gen_blk9_else
// --------------------------------------------------
// Register-based FIFO storage
//
// Uses a shift register as the storage element. Each
// shift register slot has a bit which indicates if
// the slot is occupied (credit to Sam H for the idea).
// The occupancy bits are contiguous and start from the
// lsb, so 0000, 0001, 0011, 0111, 1111 for a 4-deep
// FIFO.
//
// Each slot is enabled during a read or when it
// is unoccupied. New data is always written to every
// going-to-be-empty slot (we keep track of which ones
// are actually useful with the occupancy bits). On a
// read we shift occupied slots.
//
// The exception is the last slot, which always gets
// new data when it is unoccupied.
// --------------------------------------------------
for (i = 0; i < DEPTH-1; i = i + 1) begin : shift_reg
always @(posedge clk or posedge reset) begin
if (reset) begin
mem[i] <= 0;
end
else if (read || !mem_used[i]) begin
if (!mem_used[i+1])
mem[i] <= in_payload;
else
mem[i] <= mem[i+1];
end
end
end
always @(posedge clk, posedge reset) begin
if (reset) begin
mem[DEPTH-1] <= 0;
end
else begin
if (DEPTH == 1) begin
if (write)
mem[DEPTH-1] <= in_payload;
end
else if (!mem_used[DEPTH-1])
mem[DEPTH-1] <= in_payload;
end
end
end
endgenerate
assign read = internal_out_ready && internal_out_valid && ok_to_forward;
assign write = in_ready && in_valid;
// --------------------------------------------------
// Pointer Management
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk11
assign incremented_wr_ptr = wr_ptr + 1'b1;
assign incremented_rd_ptr = rd_ptr + 1'b1;
assign next_wr_ptr = drop_on_error ? curr_sop_ptr : write ? incremented_wr_ptr : wr_ptr;
assign next_rd_ptr = (read) ? incremented_rd_ptr : rd_ptr;
always @(posedge clk or posedge reset) begin
if (reset) begin
wr_ptr <= 0;
rd_ptr <= 0;
end
else begin
wr_ptr <= next_wr_ptr;
rd_ptr <= next_rd_ptr;
end
end
end else begin : gen_blk11_else
// --------------------------------------------------
// Shift Register Occupancy Bits
//
// Consider a 4-deep FIFO with 2 entries: 0011
// On a read and write, do not modify the bits.
// On a write, left-shift the bits to get 0111.
// On a read, right-shift the bits to get 0001.
//
// Also, on a write we set bit0 (the head), while
// clearing the tail on a read.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[0] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[0] <= 1;
else if (read) begin
if (DEPTH > 1)
mem_used[0] <= mem_used[1];
else
mem_used[0] <= 0;
end
end
end
end
if (DEPTH > 1) begin : gen_blk12
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[DEPTH-1] <= 0;
end
else begin
if (write ^ read) begin
mem_used[DEPTH-1] <= 0;
if (write)
mem_used[DEPTH-1] <= mem_used[DEPTH-2];
end
end
end
end
for (i = 1; i < DEPTH-1; i = i + 1) begin : storage_logic
always @(posedge clk, posedge reset) begin
if (reset) begin
mem_used[i] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[i] <= mem_used[i-1];
else if (read)
mem_used[i] <= mem_used[i+1];
end
end
end
end
end
endgenerate
// --------------------------------------------------
// Memory FIFO Status Management
//
// Generates the full and empty signals from the
// pointers. The FIFO is full when the next write
// pointer will be equal to the read pointer after
// a write. Reading from a FIFO clears full.
//
// The FIFO is empty when the next read pointer will
// be equal to the write pointer after a read. Writing
// to a FIFO clears empty.
//
// A simultaneous read and write must not change any of
// the empty or full flags unless there is a drop on error event.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk13
always @* begin
next_full = full;
next_empty = empty;
if (read && !write) begin
next_full = 1'b0;
if (incremented_rd_ptr == wr_ptr)
next_empty = 1'b1;
end
if (write && !read) begin
if (!drop_on_error)
next_empty = 1'b0;
else if (curr_sop_ptr == rd_ptr) // drop on error and only 1 pkt in fifo
next_empty = 1'b1;
if (incremented_wr_ptr == rd_ptr && !drop_on_error)
next_full = 1'b1;
end
if (write && read && drop_on_error) begin
if (curr_sop_ptr == next_rd_ptr)
next_empty = 1'b1;
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
empty <= 1;
full <= 0;
end
else begin
empty <= next_empty;
full <= next_full;
end
end
end else begin : gen_blk13_else
// --------------------------------------------------
// Register FIFO Status Management
//
// Full when the tail occupancy bit is 1. Empty when
// the head occupancy bit is 0.
// --------------------------------------------------
always @* begin
full = mem_used[DEPTH-1];
empty = !mem_used[0];
// ------------------------------------------
// For a single slot FIFO, reading clears the
// full status immediately.
// ------------------------------------------
if (DEPTH == 1)
full = mem_used[0] && !read;
internal_out_payload = mem[0];
// ------------------------------------------
// Writes clear empty immediately for lookahead modes.
// Note that we use in_valid instead of write to avoid
// combinational loops (in lookahead mode, qualifying
// with in_ready is meaningless).
//
// In a 1-deep FIFO, a possible combinational loop runs
// from write -> out_valid -> out_ready -> write
// ------------------------------------------
if (EMPTY_LATENCY == 0) begin
empty = !mem_used[0] && !in_valid;
if (!mem_used[0] && in_valid)
internal_out_payload = in_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Avalon-ST Signals
//
// The in_ready signal is straightforward.
//
// To match memory latency when empty latency > 1,
// out_valid assertions must be delayed by one clock
// cycle.
//
// Note: out_valid deassertions must not be delayed or
// the FIFO will underflow.
// --------------------------------------------------
assign in_ready = !full;
assign internal_out_ready = out_ready || !out_valid;
generate if (EMPTY_LATENCY > 1) begin : gen_blk14
always @(posedge clk or posedge reset) begin
if (reset)
internal_out_valid <= 0;
else begin
internal_out_valid <= !empty & ok_to_forward & ~drop_on_error;
if (read) begin
if (incremented_rd_ptr == wr_ptr)
internal_out_valid <= 1'b0;
end
end
end
end else begin : gen_blk14_else
always @* begin
internal_out_valid = !empty & ok_to_forward;
end
end
endgenerate
// --------------------------------------------------
// Single Output Pipeline Stage
//
// This output pipeline stage is enabled if the FIFO's
// empty latency is set to 3 (default). It is disabled
// for all other allowed latencies.
//
// Reason: The memory outputs are unregistered, so we have to
// register the output or fmax will drop if combinatorial
// logic is present on the output datapath.
//
// Q: The Avalon-ST spec says that I have to register my outputs
// But isn't the memory counted as a register?
// A: The path from the address lookup to the memory output is
// slow. Registering the memory outputs is a good idea.
//
// The registers get packed into the memory by the fitter
// which means minimal resources are consumed (the result
// is a altsyncram with registered outputs, available on
// all modern Altera devices).
//
// This output stage acts as an extra slot in the FIFO,
// and complicates the fill level.
// --------------------------------------------------
generate if (EMPTY_LATENCY == 3) begin : gen_blk15
always @(posedge clk or posedge reset) begin
if (reset) begin
out_valid <= 0;
out_payload <= 0;
end
else begin
if (internal_out_ready) begin
out_valid <= internal_out_valid & ok_to_forward;
out_payload <= internal_out_payload;
end
end
end
end
else begin : gen_blk15_else
always @* begin
out_valid = internal_out_valid;
out_payload = internal_out_payload;
end
end
endgenerate
// --------------------------------------------------
// Fill Level
//
// The fill level is calculated from the next write
// and read pointers to avoid unnecessary latency
// and logic.
//
// However, if the store-and-forward mode of the FIFO
// is enabled, the fill level is an up-down counter
// for fmax optimization reasons.
//
// If the output pipeline is enabled, the fill level
// must account for it, or we'll always be off by one.
// This may, or may not be important depending on the
// application.
//
// For now, we'll always calculate the exact fill level
// at the cost of an extra adder when the output stage
// is enabled.
// --------------------------------------------------
generate if (USE_FILL_LEVEL) begin : gen_blk16
wire [31:0] depth32;
assign depth32 = DEPTH;
if (USE_STORE_FORWARD) begin
reg [ADDR_WIDTH : 0] curr_packet_len_less_one;
// --------------------------------------------------
// We only drop on endofpacket. As long as we don't add to the fill
// level on the dropped endofpacket cycle, we can simply subtract
// (packet length - 1) from the fill level for dropped packets.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
curr_packet_len_less_one <= 0;
end else begin
if (write) begin
curr_packet_len_less_one <= curr_packet_len_less_one + 1'b1;
if (in_endofpacket)
curr_packet_len_less_one <= 0;
end
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
fifo_fill_level <= 0;
end else if (drop_on_error) begin
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one;
if (read)
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one - 1'b1;
end else if (write && !read) begin
fifo_fill_level <= fifo_fill_level + 1'b1;
end else if (read && !write) begin
fifo_fill_level <= fifo_fill_level - 1'b1;
end
end
end else begin
always @(posedge clk or posedge reset) begin
if (reset)
fifo_fill_level <= 0;
else if (next_full & !drop_on_error)
fifo_fill_level <= depth32[ADDR_WIDTH:0];
else begin
fifo_fill_level[ADDR_WIDTH] <= 1'b0;
fifo_fill_level[ADDR_WIDTH-1 : 0] <= next_wr_ptr - next_rd_ptr;
end
end
end
always @* begin
fill_level = fifo_fill_level;
if (EMPTY_LATENCY == 3)
fill_level = fifo_fill_level + {{ADDR_WIDTH{1'b0}}, out_valid};
end
end
else begin : gen_blk16_else
always @* begin
fill_level = 0;
end
end
endgenerate
generate if (USE_ALMOST_FULL_IF) begin : gen_blk17
assign almost_full_data = (fill_level >= almost_full_threshold);
end
else
assign almost_full_data = 0;
endgenerate
generate if (USE_ALMOST_EMPTY_IF) begin : gen_blk18
assign almost_empty_data = (fill_level <= almost_empty_threshold);
end
else
assign almost_empty_data = 0;
endgenerate
// --------------------------------------------------
// Avalon-MM Status & Control Connection Point
//
// Register map:
//
// | Addr | RW | 31 - 0 |
// | 0 | R | Fill level |
//
// The registering of this connection point means
// that there is a cycle of latency between
// reads/writes and the updating of the fill level.
// --------------------------------------------------
generate if (USE_STORE_FORWARD) begin : gen_blk19
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
cut_through_threshold <= 0;
drop_on_error_en <= 0;
csr_readdata <= 0;
pkt_mode <= 1'b1;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 5)
csr_readdata <= {31'b0, drop_on_error_en};
else if (csr_address == 4)
csr_readdata <= {8'b0, cut_through_threshold};
else if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b101)
drop_on_error_en <= csr_writedata[0];
else if(csr_address == 3'b100) begin
cut_through_threshold <= csr_writedata[23:0];
pkt_mode <= (csr_writedata[23:0] == 0);
end
else if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else if (USE_ALMOST_FULL_IF || USE_ALMOST_EMPTY_IF) begin : gen_blk19_else1
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
csr_readdata <= 0;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else begin : gen_blk19_else2
always @(posedge clk or posedge reset) begin
if (reset) begin
csr_readdata <= 0;
end
else if (csr_read) begin
csr_readdata <= 0;
if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
end
end
endgenerate
// --------------------------------------------------
// Store and forward logic
// --------------------------------------------------
// if the fifo gets full before the entire packet or the
// cut-threshold condition is met then start sending out
// data in order to avoid dead-lock situation
generate if (USE_STORE_FORWARD) begin : gen_blk20
assign wait_for_threshold = (fifo_fill_level_lt_cut_through_threshold) & wait_for_pkt ;
assign wait_for_pkt = pkt_cnt_eq_zero | (pkt_cnt_eq_one & out_pkt_leave);
assign ok_to_forward = (pkt_mode ? (~wait_for_pkt | ~pkt_has_started) :
~wait_for_threshold) | fifo_too_small_r;
assign in_pkt_eop_arrive = in_valid & in_ready & in_endofpacket;
assign in_pkt_start = in_valid & in_ready & in_startofpacket;
assign in_pkt_error = in_valid & in_ready & |in_error;
assign out_pkt_sop_leave = out_valid & out_ready & out_startofpacket;
assign out_pkt_leave = out_valid & out_ready & out_endofpacket;
assign fifo_too_small = (pkt_mode ? wait_for_pkt : wait_for_threshold) & full & out_ready;
// count packets coming and going into the fifo
always @(posedge clk or posedge reset) begin
if (reset) begin
pkt_cnt <= 0;
pkt_has_started <= 0;
sop_has_left_fifo <= 0;
fifo_too_small_r <= 0;
pkt_cnt_eq_zero <= 1'b1;
pkt_cnt_eq_one <= 1'b0;
fifo_fill_level_lt_cut_through_threshold <= 1'b1;
end
else begin
fifo_fill_level_lt_cut_through_threshold <= fifo_fill_level < cut_through_threshold;
fifo_too_small_r <= fifo_too_small;
if( in_pkt_eop_arrive )
sop_has_left_fifo <= 1'b0;
else if (out_pkt_sop_leave & pkt_cnt_eq_zero )
sop_has_left_fifo <= 1'b1;
if (in_pkt_eop_arrive & ~out_pkt_leave & ~drop_on_error ) begin
pkt_cnt <= pkt_cnt + 1'b1;
pkt_cnt_eq_zero <= 0;
if (pkt_cnt == 0)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
else if((~in_pkt_eop_arrive | drop_on_error) & out_pkt_leave) begin
pkt_cnt <= pkt_cnt - 1'b1;
if (pkt_cnt == 1)
pkt_cnt_eq_zero <= 1'b1;
else
pkt_cnt_eq_zero <= 1'b0;
if (pkt_cnt == 2)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
if (in_pkt_start)
pkt_has_started <= 1'b1;
else if (in_pkt_eop_arrive)
pkt_has_started <= 1'b0;
end
end
// drop on error logic
always @(posedge clk or posedge reset) begin
if (reset) begin
sop_ptr <= 0;
error_in_pkt <= 0;
end
else begin
// save the location of the SOP
if ( in_pkt_start )
sop_ptr <= wr_ptr;
// remember if error in pkt
// log error only if packet has already started
if (in_pkt_eop_arrive)
error_in_pkt <= 1'b0;
else if ( in_pkt_error & (pkt_has_started | in_pkt_start))
error_in_pkt <= 1'b1;
end
end
assign drop_on_error = drop_on_error_en & (error_in_pkt | in_pkt_error) & in_pkt_eop_arrive &
~sop_has_left_fifo & ~(out_pkt_sop_leave & pkt_cnt_eq_zero);
assign curr_sop_ptr = (write && in_startofpacket && in_endofpacket) ? wr_ptr : sop_ptr;
end
else begin : gen_blk20_else
assign ok_to_forward = 1'b1;
assign drop_on_error = 1'b0;
if (ADDR_WIDTH <= 1)
assign curr_sop_ptr = 1'b0;
else
assign curr_sop_ptr = {ADDR_WIDTH - 1 { 1'b0 }};
end
endgenerate
// --------------------------------------------------
// Calculates the log2ceil of the input value
// --------------------------------------------------
function integer log2ceil;
input integer val;
reg[31:0] i;
begin
i = 1;
log2ceil = 0;
while (i < val) begin
log2ceil = log2ceil + 1;
i = i[30:0] << 1;
end
end
endfunction
endmodule |
module altera_avalon_sc_fifo
#(
// --------------------------------------------------
// Parameters
// --------------------------------------------------
parameter SYMBOLS_PER_BEAT = 1,
parameter BITS_PER_SYMBOL = 8,
parameter FIFO_DEPTH = 16,
parameter CHANNEL_WIDTH = 0,
parameter ERROR_WIDTH = 0,
parameter USE_PACKETS = 0,
parameter USE_FILL_LEVEL = 0,
parameter USE_STORE_FORWARD = 0,
parameter USE_ALMOST_FULL_IF = 0,
parameter USE_ALMOST_EMPTY_IF = 0,
// --------------------------------------------------
// Empty latency is defined as the number of cycles
// required for a write to deassert the empty flag.
// For example, a latency of 1 means that the empty
// flag is deasserted on the cycle after a write.
//
// Another way to think of it is the latency for a
// write to propagate to the output.
//
// An empty latency of 0 implies lookahead, which is
// only implemented for the register-based FIFO.
// --------------------------------------------------
parameter EMPTY_LATENCY = 3,
parameter USE_MEMORY_BLOCKS = 1,
// --------------------------------------------------
// Internal Parameters
// --------------------------------------------------
parameter DATA_WIDTH = SYMBOLS_PER_BEAT * BITS_PER_SYMBOL,
parameter EMPTY_WIDTH = log2ceil(SYMBOLS_PER_BEAT)
)
(
// --------------------------------------------------
// Ports
// --------------------------------------------------
input clk,
input reset,
input [DATA_WIDTH-1: 0] in_data,
input in_valid,
input in_startofpacket,
input in_endofpacket,
input [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] in_empty,
input [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] in_error,
input [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] in_channel,
output in_ready,
output [DATA_WIDTH-1 : 0] out_data,
output reg out_valid,
output out_startofpacket,
output out_endofpacket,
output [((EMPTY_WIDTH>0) ? (EMPTY_WIDTH-1):0) : 0] out_empty,
output [((ERROR_WIDTH>0) ? (ERROR_WIDTH-1):0) : 0] out_error,
output [((CHANNEL_WIDTH>0) ? (CHANNEL_WIDTH-1):0): 0] out_channel,
input out_ready,
input [(USE_STORE_FORWARD ? 2 : 1) : 0] csr_address,
input csr_write,
input csr_read,
input [31 : 0] csr_writedata,
output reg [31 : 0] csr_readdata,
output wire almost_full_data,
output wire almost_empty_data
);
// --------------------------------------------------
// Local Parameters
// --------------------------------------------------
localparam ADDR_WIDTH = log2ceil(FIFO_DEPTH);
localparam DEPTH = FIFO_DEPTH;
localparam PKT_SIGNALS_WIDTH = 2 + EMPTY_WIDTH;
localparam PAYLOAD_WIDTH = (USE_PACKETS == 1) ?
2 + EMPTY_WIDTH + DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH:
DATA_WIDTH + ERROR_WIDTH + CHANNEL_WIDTH;
// --------------------------------------------------
// Internal Signals
// --------------------------------------------------
genvar i;
reg [PAYLOAD_WIDTH-1 : 0] mem [DEPTH-1 : 0];
reg [ADDR_WIDTH-1 : 0] wr_ptr;
reg [ADDR_WIDTH-1 : 0] rd_ptr;
reg [DEPTH-1 : 0] mem_used;
wire [ADDR_WIDTH-1 : 0] next_wr_ptr;
wire [ADDR_WIDTH-1 : 0] next_rd_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_wr_ptr;
wire [ADDR_WIDTH-1 : 0] incremented_rd_ptr;
wire [ADDR_WIDTH-1 : 0] mem_rd_ptr;
wire read;
wire write;
reg empty;
reg next_empty;
reg full;
reg next_full;
wire [PKT_SIGNALS_WIDTH-1 : 0] in_packet_signals;
wire [PKT_SIGNALS_WIDTH-1 : 0] out_packet_signals;
wire [PAYLOAD_WIDTH-1 : 0] in_payload;
reg [PAYLOAD_WIDTH-1 : 0] internal_out_payload;
reg [PAYLOAD_WIDTH-1 : 0] out_payload;
reg internal_out_valid;
wire internal_out_ready;
reg [ADDR_WIDTH : 0] fifo_fill_level;
reg [ADDR_WIDTH : 0] fill_level;
reg [ADDR_WIDTH-1 : 0] sop_ptr = 0;
wire [ADDR_WIDTH-1 : 0] curr_sop_ptr;
reg [23:0] almost_full_threshold;
reg [23:0] almost_empty_threshold;
reg [23:0] cut_through_threshold;
reg [15:0] pkt_cnt;
reg drop_on_error_en;
reg error_in_pkt;
reg pkt_has_started;
reg sop_has_left_fifo;
reg fifo_too_small_r;
reg pkt_cnt_eq_zero;
reg pkt_cnt_eq_one;
wire wait_for_threshold;
reg pkt_mode;
wire wait_for_pkt;
wire ok_to_forward;
wire in_pkt_eop_arrive;
wire out_pkt_leave;
wire in_pkt_start;
wire in_pkt_error;
wire drop_on_error;
wire fifo_too_small;
wire out_pkt_sop_leave;
wire [31:0] max_fifo_size;
reg fifo_fill_level_lt_cut_through_threshold;
// --------------------------------------------------
// Define Payload
//
// Icky part where we decide which signals form the
// payload to the FIFO with generate blocks.
// --------------------------------------------------
generate
if (EMPTY_WIDTH > 0) begin : gen_blk1
assign in_packet_signals = {in_startofpacket, in_endofpacket, in_empty};
assign {out_startofpacket, out_endofpacket, out_empty} = out_packet_signals;
end
else begin : gen_blk1_else
assign out_empty = in_error;
assign in_packet_signals = {in_startofpacket, in_endofpacket};
assign {out_startofpacket, out_endofpacket} = out_packet_signals;
end
endgenerate
generate
if (USE_PACKETS) begin : gen_blk2
if (ERROR_WIDTH > 0) begin : gen_blk3
if (CHANNEL_WIDTH > 0) begin : gen_blk4
assign in_payload = {in_packet_signals, in_data, in_error, in_channel};
assign {out_packet_signals, out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk4_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data, in_error};
assign {out_packet_signals, out_data, out_error} = out_payload;
end
end
else begin : gen_blk3_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk5
assign in_payload = {in_packet_signals, in_data, in_channel};
assign {out_packet_signals, out_data, out_channel} = out_payload;
end
else begin : gen_blk5_else
assign out_channel = in_channel;
assign in_payload = {in_packet_signals, in_data};
assign {out_packet_signals, out_data} = out_payload;
end
end
end
else begin : gen_blk2_else
assign out_packet_signals = 0;
if (ERROR_WIDTH > 0) begin : gen_blk6
if (CHANNEL_WIDTH > 0) begin : gen_blk7
assign in_payload = {in_data, in_error, in_channel};
assign {out_data, out_error, out_channel} = out_payload;
end
else begin : gen_blk7_else
assign out_channel = in_channel;
assign in_payload = {in_data, in_error};
assign {out_data, out_error} = out_payload;
end
end
else begin : gen_blk6_else
assign out_error = in_error;
if (CHANNEL_WIDTH > 0) begin : gen_blk8
assign in_payload = {in_data, in_channel};
assign {out_data, out_channel} = out_payload;
end
else begin : gen_blk8_else
assign out_channel = in_channel;
assign in_payload = in_data;
assign out_data = out_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Memory-based FIFO storage
//
// To allow a ready latency of 0, the read index is
// obtained from the next read pointer and memory
// outputs are unregistered.
//
// If the empty latency is 1, we infer bypass logic
// around the memory so writes propagate to the
// outputs on the next cycle.
//
// Do not change the way this is coded: Quartus needs
// a perfect match to the template, and any attempt to
// refactor the two always blocks into one will break
// memory inference.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk9
if (EMPTY_LATENCY == 1) begin : gen_blk10
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] = in_payload;
internal_out_payload = mem[mem_rd_ptr];
end
end else begin : gen_blk10_else
always @(posedge clk) begin
if (in_valid && in_ready)
mem[wr_ptr] <= in_payload;
internal_out_payload <= mem[mem_rd_ptr];
end
end
assign mem_rd_ptr = next_rd_ptr;
end else begin : gen_blk9_else
// --------------------------------------------------
// Register-based FIFO storage
//
// Uses a shift register as the storage element. Each
// shift register slot has a bit which indicates if
// the slot is occupied (credit to Sam H for the idea).
// The occupancy bits are contiguous and start from the
// lsb, so 0000, 0001, 0011, 0111, 1111 for a 4-deep
// FIFO.
//
// Each slot is enabled during a read or when it
// is unoccupied. New data is always written to every
// going-to-be-empty slot (we keep track of which ones
// are actually useful with the occupancy bits). On a
// read we shift occupied slots.
//
// The exception is the last slot, which always gets
// new data when it is unoccupied.
// --------------------------------------------------
for (i = 0; i < DEPTH-1; i = i + 1) begin : shift_reg
always @(posedge clk or posedge reset) begin
if (reset) begin
mem[i] <= 0;
end
else if (read || !mem_used[i]) begin
if (!mem_used[i+1])
mem[i] <= in_payload;
else
mem[i] <= mem[i+1];
end
end
end
always @(posedge clk, posedge reset) begin
if (reset) begin
mem[DEPTH-1] <= 0;
end
else begin
if (DEPTH == 1) begin
if (write)
mem[DEPTH-1] <= in_payload;
end
else if (!mem_used[DEPTH-1])
mem[DEPTH-1] <= in_payload;
end
end
end
endgenerate
assign read = internal_out_ready && internal_out_valid && ok_to_forward;
assign write = in_ready && in_valid;
// --------------------------------------------------
// Pointer Management
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk11
assign incremented_wr_ptr = wr_ptr + 1'b1;
assign incremented_rd_ptr = rd_ptr + 1'b1;
assign next_wr_ptr = drop_on_error ? curr_sop_ptr : write ? incremented_wr_ptr : wr_ptr;
assign next_rd_ptr = (read) ? incremented_rd_ptr : rd_ptr;
always @(posedge clk or posedge reset) begin
if (reset) begin
wr_ptr <= 0;
rd_ptr <= 0;
end
else begin
wr_ptr <= next_wr_ptr;
rd_ptr <= next_rd_ptr;
end
end
end else begin : gen_blk11_else
// --------------------------------------------------
// Shift Register Occupancy Bits
//
// Consider a 4-deep FIFO with 2 entries: 0011
// On a read and write, do not modify the bits.
// On a write, left-shift the bits to get 0111.
// On a read, right-shift the bits to get 0001.
//
// Also, on a write we set bit0 (the head), while
// clearing the tail on a read.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[0] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[0] <= 1;
else if (read) begin
if (DEPTH > 1)
mem_used[0] <= mem_used[1];
else
mem_used[0] <= 0;
end
end
end
end
if (DEPTH > 1) begin : gen_blk12
always @(posedge clk or posedge reset) begin
if (reset) begin
mem_used[DEPTH-1] <= 0;
end
else begin
if (write ^ read) begin
mem_used[DEPTH-1] <= 0;
if (write)
mem_used[DEPTH-1] <= mem_used[DEPTH-2];
end
end
end
end
for (i = 1; i < DEPTH-1; i = i + 1) begin : storage_logic
always @(posedge clk, posedge reset) begin
if (reset) begin
mem_used[i] <= 0;
end
else begin
if (write ^ read) begin
if (write)
mem_used[i] <= mem_used[i-1];
else if (read)
mem_used[i] <= mem_used[i+1];
end
end
end
end
end
endgenerate
// --------------------------------------------------
// Memory FIFO Status Management
//
// Generates the full and empty signals from the
// pointers. The FIFO is full when the next write
// pointer will be equal to the read pointer after
// a write. Reading from a FIFO clears full.
//
// The FIFO is empty when the next read pointer will
// be equal to the write pointer after a read. Writing
// to a FIFO clears empty.
//
// A simultaneous read and write must not change any of
// the empty or full flags unless there is a drop on error event.
// --------------------------------------------------
generate if (USE_MEMORY_BLOCKS == 1) begin : gen_blk13
always @* begin
next_full = full;
next_empty = empty;
if (read && !write) begin
next_full = 1'b0;
if (incremented_rd_ptr == wr_ptr)
next_empty = 1'b1;
end
if (write && !read) begin
if (!drop_on_error)
next_empty = 1'b0;
else if (curr_sop_ptr == rd_ptr) // drop on error and only 1 pkt in fifo
next_empty = 1'b1;
if (incremented_wr_ptr == rd_ptr && !drop_on_error)
next_full = 1'b1;
end
if (write && read && drop_on_error) begin
if (curr_sop_ptr == next_rd_ptr)
next_empty = 1'b1;
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
empty <= 1;
full <= 0;
end
else begin
empty <= next_empty;
full <= next_full;
end
end
end else begin : gen_blk13_else
// --------------------------------------------------
// Register FIFO Status Management
//
// Full when the tail occupancy bit is 1. Empty when
// the head occupancy bit is 0.
// --------------------------------------------------
always @* begin
full = mem_used[DEPTH-1];
empty = !mem_used[0];
// ------------------------------------------
// For a single slot FIFO, reading clears the
// full status immediately.
// ------------------------------------------
if (DEPTH == 1)
full = mem_used[0] && !read;
internal_out_payload = mem[0];
// ------------------------------------------
// Writes clear empty immediately for lookahead modes.
// Note that we use in_valid instead of write to avoid
// combinational loops (in lookahead mode, qualifying
// with in_ready is meaningless).
//
// In a 1-deep FIFO, a possible combinational loop runs
// from write -> out_valid -> out_ready -> write
// ------------------------------------------
if (EMPTY_LATENCY == 0) begin
empty = !mem_used[0] && !in_valid;
if (!mem_used[0] && in_valid)
internal_out_payload = in_payload;
end
end
end
endgenerate
// --------------------------------------------------
// Avalon-ST Signals
//
// The in_ready signal is straightforward.
//
// To match memory latency when empty latency > 1,
// out_valid assertions must be delayed by one clock
// cycle.
//
// Note: out_valid deassertions must not be delayed or
// the FIFO will underflow.
// --------------------------------------------------
assign in_ready = !full;
assign internal_out_ready = out_ready || !out_valid;
generate if (EMPTY_LATENCY > 1) begin : gen_blk14
always @(posedge clk or posedge reset) begin
if (reset)
internal_out_valid <= 0;
else begin
internal_out_valid <= !empty & ok_to_forward & ~drop_on_error;
if (read) begin
if (incremented_rd_ptr == wr_ptr)
internal_out_valid <= 1'b0;
end
end
end
end else begin : gen_blk14_else
always @* begin
internal_out_valid = !empty & ok_to_forward;
end
end
endgenerate
// --------------------------------------------------
// Single Output Pipeline Stage
//
// This output pipeline stage is enabled if the FIFO's
// empty latency is set to 3 (default). It is disabled
// for all other allowed latencies.
//
// Reason: The memory outputs are unregistered, so we have to
// register the output or fmax will drop if combinatorial
// logic is present on the output datapath.
//
// Q: The Avalon-ST spec says that I have to register my outputs
// But isn't the memory counted as a register?
// A: The path from the address lookup to the memory output is
// slow. Registering the memory outputs is a good idea.
//
// The registers get packed into the memory by the fitter
// which means minimal resources are consumed (the result
// is a altsyncram with registered outputs, available on
// all modern Altera devices).
//
// This output stage acts as an extra slot in the FIFO,
// and complicates the fill level.
// --------------------------------------------------
generate if (EMPTY_LATENCY == 3) begin : gen_blk15
always @(posedge clk or posedge reset) begin
if (reset) begin
out_valid <= 0;
out_payload <= 0;
end
else begin
if (internal_out_ready) begin
out_valid <= internal_out_valid & ok_to_forward;
out_payload <= internal_out_payload;
end
end
end
end
else begin : gen_blk15_else
always @* begin
out_valid = internal_out_valid;
out_payload = internal_out_payload;
end
end
endgenerate
// --------------------------------------------------
// Fill Level
//
// The fill level is calculated from the next write
// and read pointers to avoid unnecessary latency
// and logic.
//
// However, if the store-and-forward mode of the FIFO
// is enabled, the fill level is an up-down counter
// for fmax optimization reasons.
//
// If the output pipeline is enabled, the fill level
// must account for it, or we'll always be off by one.
// This may, or may not be important depending on the
// application.
//
// For now, we'll always calculate the exact fill level
// at the cost of an extra adder when the output stage
// is enabled.
// --------------------------------------------------
generate if (USE_FILL_LEVEL) begin : gen_blk16
wire [31:0] depth32;
assign depth32 = DEPTH;
if (USE_STORE_FORWARD) begin
reg [ADDR_WIDTH : 0] curr_packet_len_less_one;
// --------------------------------------------------
// We only drop on endofpacket. As long as we don't add to the fill
// level on the dropped endofpacket cycle, we can simply subtract
// (packet length - 1) from the fill level for dropped packets.
// --------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
curr_packet_len_less_one <= 0;
end else begin
if (write) begin
curr_packet_len_less_one <= curr_packet_len_less_one + 1'b1;
if (in_endofpacket)
curr_packet_len_less_one <= 0;
end
end
end
always @(posedge clk or posedge reset) begin
if (reset) begin
fifo_fill_level <= 0;
end else if (drop_on_error) begin
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one;
if (read)
fifo_fill_level <= fifo_fill_level - curr_packet_len_less_one - 1'b1;
end else if (write && !read) begin
fifo_fill_level <= fifo_fill_level + 1'b1;
end else if (read && !write) begin
fifo_fill_level <= fifo_fill_level - 1'b1;
end
end
end else begin
always @(posedge clk or posedge reset) begin
if (reset)
fifo_fill_level <= 0;
else if (next_full & !drop_on_error)
fifo_fill_level <= depth32[ADDR_WIDTH:0];
else begin
fifo_fill_level[ADDR_WIDTH] <= 1'b0;
fifo_fill_level[ADDR_WIDTH-1 : 0] <= next_wr_ptr - next_rd_ptr;
end
end
end
always @* begin
fill_level = fifo_fill_level;
if (EMPTY_LATENCY == 3)
fill_level = fifo_fill_level + {{ADDR_WIDTH{1'b0}}, out_valid};
end
end
else begin : gen_blk16_else
always @* begin
fill_level = 0;
end
end
endgenerate
generate if (USE_ALMOST_FULL_IF) begin : gen_blk17
assign almost_full_data = (fill_level >= almost_full_threshold);
end
else
assign almost_full_data = 0;
endgenerate
generate if (USE_ALMOST_EMPTY_IF) begin : gen_blk18
assign almost_empty_data = (fill_level <= almost_empty_threshold);
end
else
assign almost_empty_data = 0;
endgenerate
// --------------------------------------------------
// Avalon-MM Status & Control Connection Point
//
// Register map:
//
// | Addr | RW | 31 - 0 |
// | 0 | R | Fill level |
//
// The registering of this connection point means
// that there is a cycle of latency between
// reads/writes and the updating of the fill level.
// --------------------------------------------------
generate if (USE_STORE_FORWARD) begin : gen_blk19
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
cut_through_threshold <= 0;
drop_on_error_en <= 0;
csr_readdata <= 0;
pkt_mode <= 1'b1;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 5)
csr_readdata <= {31'b0, drop_on_error_en};
else if (csr_address == 4)
csr_readdata <= {8'b0, cut_through_threshold};
else if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b101)
drop_on_error_en <= csr_writedata[0];
else if(csr_address == 3'b100) begin
cut_through_threshold <= csr_writedata[23:0];
pkt_mode <= (csr_writedata[23:0] == 0);
end
else if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else if (USE_ALMOST_FULL_IF || USE_ALMOST_EMPTY_IF) begin : gen_blk19_else1
assign max_fifo_size = FIFO_DEPTH - 1;
always @(posedge clk or posedge reset) begin
if (reset) begin
almost_full_threshold <= max_fifo_size[23 : 0];
almost_empty_threshold <= 0;
csr_readdata <= 0;
end
else begin
if (csr_read) begin
csr_readdata <= 32'b0;
if (csr_address == 3)
csr_readdata <= {8'b0, almost_empty_threshold};
else if (csr_address == 2)
csr_readdata <= {8'b0, almost_full_threshold};
else if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
else if (csr_write) begin
if(csr_address == 3'b011)
almost_empty_threshold <= csr_writedata[23:0];
else if(csr_address == 3'b010)
almost_full_threshold <= csr_writedata[23:0];
end
end
end
end
else begin : gen_blk19_else2
always @(posedge clk or posedge reset) begin
if (reset) begin
csr_readdata <= 0;
end
else if (csr_read) begin
csr_readdata <= 0;
if (csr_address == 0)
csr_readdata <= {{(31 - ADDR_WIDTH){1'b0}}, fill_level};
end
end
end
endgenerate
// --------------------------------------------------
// Store and forward logic
// --------------------------------------------------
// if the fifo gets full before the entire packet or the
// cut-threshold condition is met then start sending out
// data in order to avoid dead-lock situation
generate if (USE_STORE_FORWARD) begin : gen_blk20
assign wait_for_threshold = (fifo_fill_level_lt_cut_through_threshold) & wait_for_pkt ;
assign wait_for_pkt = pkt_cnt_eq_zero | (pkt_cnt_eq_one & out_pkt_leave);
assign ok_to_forward = (pkt_mode ? (~wait_for_pkt | ~pkt_has_started) :
~wait_for_threshold) | fifo_too_small_r;
assign in_pkt_eop_arrive = in_valid & in_ready & in_endofpacket;
assign in_pkt_start = in_valid & in_ready & in_startofpacket;
assign in_pkt_error = in_valid & in_ready & |in_error;
assign out_pkt_sop_leave = out_valid & out_ready & out_startofpacket;
assign out_pkt_leave = out_valid & out_ready & out_endofpacket;
assign fifo_too_small = (pkt_mode ? wait_for_pkt : wait_for_threshold) & full & out_ready;
// count packets coming and going into the fifo
always @(posedge clk or posedge reset) begin
if (reset) begin
pkt_cnt <= 0;
pkt_has_started <= 0;
sop_has_left_fifo <= 0;
fifo_too_small_r <= 0;
pkt_cnt_eq_zero <= 1'b1;
pkt_cnt_eq_one <= 1'b0;
fifo_fill_level_lt_cut_through_threshold <= 1'b1;
end
else begin
fifo_fill_level_lt_cut_through_threshold <= fifo_fill_level < cut_through_threshold;
fifo_too_small_r <= fifo_too_small;
if( in_pkt_eop_arrive )
sop_has_left_fifo <= 1'b0;
else if (out_pkt_sop_leave & pkt_cnt_eq_zero )
sop_has_left_fifo <= 1'b1;
if (in_pkt_eop_arrive & ~out_pkt_leave & ~drop_on_error ) begin
pkt_cnt <= pkt_cnt + 1'b1;
pkt_cnt_eq_zero <= 0;
if (pkt_cnt == 0)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
else if((~in_pkt_eop_arrive | drop_on_error) & out_pkt_leave) begin
pkt_cnt <= pkt_cnt - 1'b1;
if (pkt_cnt == 1)
pkt_cnt_eq_zero <= 1'b1;
else
pkt_cnt_eq_zero <= 1'b0;
if (pkt_cnt == 2)
pkt_cnt_eq_one <= 1'b1;
else
pkt_cnt_eq_one <= 1'b0;
end
if (in_pkt_start)
pkt_has_started <= 1'b1;
else if (in_pkt_eop_arrive)
pkt_has_started <= 1'b0;
end
end
// drop on error logic
always @(posedge clk or posedge reset) begin
if (reset) begin
sop_ptr <= 0;
error_in_pkt <= 0;
end
else begin
// save the location of the SOP
if ( in_pkt_start )
sop_ptr <= wr_ptr;
// remember if error in pkt
// log error only if packet has already started
if (in_pkt_eop_arrive)
error_in_pkt <= 1'b0;
else if ( in_pkt_error & (pkt_has_started | in_pkt_start))
error_in_pkt <= 1'b1;
end
end
assign drop_on_error = drop_on_error_en & (error_in_pkt | in_pkt_error) & in_pkt_eop_arrive &
~sop_has_left_fifo & ~(out_pkt_sop_leave & pkt_cnt_eq_zero);
assign curr_sop_ptr = (write && in_startofpacket && in_endofpacket) ? wr_ptr : sop_ptr;
end
else begin : gen_blk20_else
assign ok_to_forward = 1'b1;
assign drop_on_error = 1'b0;
if (ADDR_WIDTH <= 1)
assign curr_sop_ptr = 1'b0;
else
assign curr_sop_ptr = {ADDR_WIDTH - 1 { 1'b0 }};
end
endgenerate
// --------------------------------------------------
// Calculates the log2ceil of the input value
// --------------------------------------------------
function integer log2ceil;
input integer val;
reg[31:0] i;
begin
i = 1;
log2ceil = 0;
while (i < val) begin
log2ceil = log2ceil + 1;
i = i[30:0] << 1;
end
end
endfunction
endmodule |
module axi_protocol_converter_v2_1_r_axi3_conv #
(
parameter C_FAMILY = "none",
parameter integer C_AXI_ID_WIDTH = 1,
parameter integer C_AXI_ADDR_WIDTH = 32,
parameter integer C_AXI_DATA_WIDTH = 32,
parameter integer C_AXI_SUPPORTS_USER_SIGNALS = 0,
parameter integer C_AXI_RUSER_WIDTH = 1,
parameter integer C_SUPPORT_SPLITTING = 1,
// Implement transaction splitting logic.
// Disabled whan all connected masters are AXI3 and have same or narrower data width.
parameter integer C_SUPPORT_BURSTS = 1
// Disabled when all connected masters are AxiLite,
// allowing logic to be simplified.
)
(
// System Signals
input wire ACLK,
input wire ARESET,
// Command Interface
input wire cmd_valid,
input wire cmd_split,
output wire cmd_ready,
// Slave Interface Read Data Ports
output wire [C_AXI_ID_WIDTH-1:0] S_AXI_RID,
output wire [C_AXI_DATA_WIDTH-1:0] S_AXI_RDATA,
output wire [2-1:0] S_AXI_RRESP,
output wire S_AXI_RLAST,
output wire [C_AXI_RUSER_WIDTH-1:0] S_AXI_RUSER,
output wire S_AXI_RVALID,
input wire S_AXI_RREADY,
// Master Interface Read Data Ports
input wire [C_AXI_ID_WIDTH-1:0] M_AXI_RID,
input wire [C_AXI_DATA_WIDTH-1:0] M_AXI_RDATA,
input wire [2-1:0] M_AXI_RRESP,
input wire M_AXI_RLAST,
input wire [C_AXI_RUSER_WIDTH-1:0] M_AXI_RUSER,
input wire M_AXI_RVALID,
output wire M_AXI_RREADY
);
/////////////////////////////////////////////////////////////////////////////
// Variables for generating parameter controlled instances.
/////////////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////
// Local params
/////////////////////////////////////////////////////////////////////////////
// Constants for packing levels.
localparam [2-1:0] C_RESP_OKAY = 2'b00;
localparam [2-1:0] C_RESP_EXOKAY = 2'b01;
localparam [2-1:0] C_RESP_SLVERROR = 2'b10;
localparam [2-1:0] C_RESP_DECERR = 2'b11;
/////////////////////////////////////////////////////////////////////////////
// Functions
/////////////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////
// Internal signals
/////////////////////////////////////////////////////////////////////////////
// Throttling help signals.
wire cmd_ready_i;
wire pop_si_data;
wire si_stalling;
// Internal MI-side control signals.
wire M_AXI_RREADY_I;
// Internal signals for SI-side.
wire [C_AXI_ID_WIDTH-1:0] S_AXI_RID_I;
wire [C_AXI_DATA_WIDTH-1:0] S_AXI_RDATA_I;
wire [2-1:0] S_AXI_RRESP_I;
wire S_AXI_RLAST_I;
wire [C_AXI_RUSER_WIDTH-1:0] S_AXI_RUSER_I;
wire S_AXI_RVALID_I;
wire S_AXI_RREADY_I;
/////////////////////////////////////////////////////////////////////////////
// Handle interface handshaking:
//
// Forward data from MI-Side to SI-Side while a command is available. When
// the transaction has completed the command is popped from the Command FIFO.
//
//
/////////////////////////////////////////////////////////////////////////////
// Pop word from SI-side.
assign M_AXI_RREADY_I = ~si_stalling & cmd_valid;
assign M_AXI_RREADY = M_AXI_RREADY_I;
// Indicate when there is data available @ SI-side.
assign S_AXI_RVALID_I = M_AXI_RVALID & cmd_valid;
// Get SI-side data.
assign pop_si_data = S_AXI_RVALID_I & S_AXI_RREADY_I;
// Signal that the command is done (so that it can be poped from command queue).
assign cmd_ready_i = cmd_valid & pop_si_data & M_AXI_RLAST;
assign cmd_ready = cmd_ready_i;
// Detect when MI-side is stalling.
assign si_stalling = S_AXI_RVALID_I & ~S_AXI_RREADY_I;
/////////////////////////////////////////////////////////////////////////////
// Simple AXI signal forwarding:
//
// USER, ID, DATA and RRESP passes through untouched.
//
// LAST has to be filtered to remove any intermediate LAST (due to split
// trasactions). LAST is only removed for the first parts of a split
// transaction. When splitting is unsupported is the LAST filtering completely
// completely removed.
//
/////////////////////////////////////////////////////////////////////////////
// Calculate last, i.e. mask from split transactions.
assign S_AXI_RLAST_I = M_AXI_RLAST &
( ~cmd_split | ( C_SUPPORT_SPLITTING == 0 ) );
// Data is passed through.
assign S_AXI_RID_I = M_AXI_RID;
assign S_AXI_RUSER_I = M_AXI_RUSER;
assign S_AXI_RDATA_I = M_AXI_RDATA;
assign S_AXI_RRESP_I = M_AXI_RRESP;
/////////////////////////////////////////////////////////////////////////////
// SI-side output handling
//
/////////////////////////////////////////////////////////////////////////////
// TODO: registered?
assign S_AXI_RREADY_I = S_AXI_RREADY;
assign S_AXI_RVALID = S_AXI_RVALID_I;
assign S_AXI_RID = S_AXI_RID_I;
assign S_AXI_RDATA = S_AXI_RDATA_I;
assign S_AXI_RRESP = S_AXI_RRESP_I;
assign S_AXI_RLAST = S_AXI_RLAST_I;
assign S_AXI_RUSER = S_AXI_RUSER_I;
endmodule |
module axi_protocol_converter_v2_1_r_axi3_conv #
(
parameter C_FAMILY = "none",
parameter integer C_AXI_ID_WIDTH = 1,
parameter integer C_AXI_ADDR_WIDTH = 32,
parameter integer C_AXI_DATA_WIDTH = 32,
parameter integer C_AXI_SUPPORTS_USER_SIGNALS = 0,
parameter integer C_AXI_RUSER_WIDTH = 1,
parameter integer C_SUPPORT_SPLITTING = 1,
// Implement transaction splitting logic.
// Disabled whan all connected masters are AXI3 and have same or narrower data width.
parameter integer C_SUPPORT_BURSTS = 1
// Disabled when all connected masters are AxiLite,
// allowing logic to be simplified.
)
(
// System Signals
input wire ACLK,
input wire ARESET,
// Command Interface
input wire cmd_valid,
input wire cmd_split,
output wire cmd_ready,
// Slave Interface Read Data Ports
output wire [C_AXI_ID_WIDTH-1:0] S_AXI_RID,
output wire [C_AXI_DATA_WIDTH-1:0] S_AXI_RDATA,
output wire [2-1:0] S_AXI_RRESP,
output wire S_AXI_RLAST,
output wire [C_AXI_RUSER_WIDTH-1:0] S_AXI_RUSER,
output wire S_AXI_RVALID,
input wire S_AXI_RREADY,
// Master Interface Read Data Ports
input wire [C_AXI_ID_WIDTH-1:0] M_AXI_RID,
input wire [C_AXI_DATA_WIDTH-1:0] M_AXI_RDATA,
input wire [2-1:0] M_AXI_RRESP,
input wire M_AXI_RLAST,
input wire [C_AXI_RUSER_WIDTH-1:0] M_AXI_RUSER,
input wire M_AXI_RVALID,
output wire M_AXI_RREADY
);
/////////////////////////////////////////////////////////////////////////////
// Variables for generating parameter controlled instances.
/////////////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////
// Local params
/////////////////////////////////////////////////////////////////////////////
// Constants for packing levels.
localparam [2-1:0] C_RESP_OKAY = 2'b00;
localparam [2-1:0] C_RESP_EXOKAY = 2'b01;
localparam [2-1:0] C_RESP_SLVERROR = 2'b10;
localparam [2-1:0] C_RESP_DECERR = 2'b11;
/////////////////////////////////////////////////////////////////////////////
// Functions
/////////////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////
// Internal signals
/////////////////////////////////////////////////////////////////////////////
// Throttling help signals.
wire cmd_ready_i;
wire pop_si_data;
wire si_stalling;
// Internal MI-side control signals.
wire M_AXI_RREADY_I;
// Internal signals for SI-side.
wire [C_AXI_ID_WIDTH-1:0] S_AXI_RID_I;
wire [C_AXI_DATA_WIDTH-1:0] S_AXI_RDATA_I;
wire [2-1:0] S_AXI_RRESP_I;
wire S_AXI_RLAST_I;
wire [C_AXI_RUSER_WIDTH-1:0] S_AXI_RUSER_I;
wire S_AXI_RVALID_I;
wire S_AXI_RREADY_I;
/////////////////////////////////////////////////////////////////////////////
// Handle interface handshaking:
//
// Forward data from MI-Side to SI-Side while a command is available. When
// the transaction has completed the command is popped from the Command FIFO.
//
//
/////////////////////////////////////////////////////////////////////////////
// Pop word from SI-side.
assign M_AXI_RREADY_I = ~si_stalling & cmd_valid;
assign M_AXI_RREADY = M_AXI_RREADY_I;
// Indicate when there is data available @ SI-side.
assign S_AXI_RVALID_I = M_AXI_RVALID & cmd_valid;
// Get SI-side data.
assign pop_si_data = S_AXI_RVALID_I & S_AXI_RREADY_I;
// Signal that the command is done (so that it can be poped from command queue).
assign cmd_ready_i = cmd_valid & pop_si_data & M_AXI_RLAST;
assign cmd_ready = cmd_ready_i;
// Detect when MI-side is stalling.
assign si_stalling = S_AXI_RVALID_I & ~S_AXI_RREADY_I;
/////////////////////////////////////////////////////////////////////////////
// Simple AXI signal forwarding:
//
// USER, ID, DATA and RRESP passes through untouched.
//
// LAST has to be filtered to remove any intermediate LAST (due to split
// trasactions). LAST is only removed for the first parts of a split
// transaction. When splitting is unsupported is the LAST filtering completely
// completely removed.
//
/////////////////////////////////////////////////////////////////////////////
// Calculate last, i.e. mask from split transactions.
assign S_AXI_RLAST_I = M_AXI_RLAST &
( ~cmd_split | ( C_SUPPORT_SPLITTING == 0 ) );
// Data is passed through.
assign S_AXI_RID_I = M_AXI_RID;
assign S_AXI_RUSER_I = M_AXI_RUSER;
assign S_AXI_RDATA_I = M_AXI_RDATA;
assign S_AXI_RRESP_I = M_AXI_RRESP;
/////////////////////////////////////////////////////////////////////////////
// SI-side output handling
//
/////////////////////////////////////////////////////////////////////////////
// TODO: registered?
assign S_AXI_RREADY_I = S_AXI_RREADY;
assign S_AXI_RVALID = S_AXI_RVALID_I;
assign S_AXI_RID = S_AXI_RID_I;
assign S_AXI_RDATA = S_AXI_RDATA_I;
assign S_AXI_RRESP = S_AXI_RRESP_I;
assign S_AXI_RLAST = S_AXI_RLAST_I;
assign S_AXI_RUSER = S_AXI_RUSER_I;
endmodule |
module axi_protocol_converter_v2_1_r_axi3_conv #
(
parameter C_FAMILY = "none",
parameter integer C_AXI_ID_WIDTH = 1,
parameter integer C_AXI_ADDR_WIDTH = 32,
parameter integer C_AXI_DATA_WIDTH = 32,
parameter integer C_AXI_SUPPORTS_USER_SIGNALS = 0,
parameter integer C_AXI_RUSER_WIDTH = 1,
parameter integer C_SUPPORT_SPLITTING = 1,
// Implement transaction splitting logic.
// Disabled whan all connected masters are AXI3 and have same or narrower data width.
parameter integer C_SUPPORT_BURSTS = 1
// Disabled when all connected masters are AxiLite,
// allowing logic to be simplified.
)
(
// System Signals
input wire ACLK,
input wire ARESET,
// Command Interface
input wire cmd_valid,
input wire cmd_split,
output wire cmd_ready,
// Slave Interface Read Data Ports
output wire [C_AXI_ID_WIDTH-1:0] S_AXI_RID,
output wire [C_AXI_DATA_WIDTH-1:0] S_AXI_RDATA,
output wire [2-1:0] S_AXI_RRESP,
output wire S_AXI_RLAST,
output wire [C_AXI_RUSER_WIDTH-1:0] S_AXI_RUSER,
output wire S_AXI_RVALID,
input wire S_AXI_RREADY,
// Master Interface Read Data Ports
input wire [C_AXI_ID_WIDTH-1:0] M_AXI_RID,
input wire [C_AXI_DATA_WIDTH-1:0] M_AXI_RDATA,
input wire [2-1:0] M_AXI_RRESP,
input wire M_AXI_RLAST,
input wire [C_AXI_RUSER_WIDTH-1:0] M_AXI_RUSER,
input wire M_AXI_RVALID,
output wire M_AXI_RREADY
);
/////////////////////////////////////////////////////////////////////////////
// Variables for generating parameter controlled instances.
/////////////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////
// Local params
/////////////////////////////////////////////////////////////////////////////
// Constants for packing levels.
localparam [2-1:0] C_RESP_OKAY = 2'b00;
localparam [2-1:0] C_RESP_EXOKAY = 2'b01;
localparam [2-1:0] C_RESP_SLVERROR = 2'b10;
localparam [2-1:0] C_RESP_DECERR = 2'b11;
/////////////////////////////////////////////////////////////////////////////
// Functions
/////////////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////
// Internal signals
/////////////////////////////////////////////////////////////////////////////
// Throttling help signals.
wire cmd_ready_i;
wire pop_si_data;
wire si_stalling;
// Internal MI-side control signals.
wire M_AXI_RREADY_I;
// Internal signals for SI-side.
wire [C_AXI_ID_WIDTH-1:0] S_AXI_RID_I;
wire [C_AXI_DATA_WIDTH-1:0] S_AXI_RDATA_I;
wire [2-1:0] S_AXI_RRESP_I;
wire S_AXI_RLAST_I;
wire [C_AXI_RUSER_WIDTH-1:0] S_AXI_RUSER_I;
wire S_AXI_RVALID_I;
wire S_AXI_RREADY_I;
/////////////////////////////////////////////////////////////////////////////
// Handle interface handshaking:
//
// Forward data from MI-Side to SI-Side while a command is available. When
// the transaction has completed the command is popped from the Command FIFO.
//
//
/////////////////////////////////////////////////////////////////////////////
// Pop word from SI-side.
assign M_AXI_RREADY_I = ~si_stalling & cmd_valid;
assign M_AXI_RREADY = M_AXI_RREADY_I;
// Indicate when there is data available @ SI-side.
assign S_AXI_RVALID_I = M_AXI_RVALID & cmd_valid;
// Get SI-side data.
assign pop_si_data = S_AXI_RVALID_I & S_AXI_RREADY_I;
// Signal that the command is done (so that it can be poped from command queue).
assign cmd_ready_i = cmd_valid & pop_si_data & M_AXI_RLAST;
assign cmd_ready = cmd_ready_i;
// Detect when MI-side is stalling.
assign si_stalling = S_AXI_RVALID_I & ~S_AXI_RREADY_I;
/////////////////////////////////////////////////////////////////////////////
// Simple AXI signal forwarding:
//
// USER, ID, DATA and RRESP passes through untouched.
//
// LAST has to be filtered to remove any intermediate LAST (due to split
// trasactions). LAST is only removed for the first parts of a split
// transaction. When splitting is unsupported is the LAST filtering completely
// completely removed.
//
/////////////////////////////////////////////////////////////////////////////
// Calculate last, i.e. mask from split transactions.
assign S_AXI_RLAST_I = M_AXI_RLAST &
( ~cmd_split | ( C_SUPPORT_SPLITTING == 0 ) );
// Data is passed through.
assign S_AXI_RID_I = M_AXI_RID;
assign S_AXI_RUSER_I = M_AXI_RUSER;
assign S_AXI_RDATA_I = M_AXI_RDATA;
assign S_AXI_RRESP_I = M_AXI_RRESP;
/////////////////////////////////////////////////////////////////////////////
// SI-side output handling
//
/////////////////////////////////////////////////////////////////////////////
// TODO: registered?
assign S_AXI_RREADY_I = S_AXI_RREADY;
assign S_AXI_RVALID = S_AXI_RVALID_I;
assign S_AXI_RID = S_AXI_RID_I;
assign S_AXI_RDATA = S_AXI_RDATA_I;
assign S_AXI_RRESP = S_AXI_RRESP_I;
assign S_AXI_RLAST = S_AXI_RLAST_I;
assign S_AXI_RUSER = S_AXI_RUSER_I;
endmodule |
module axi_protocol_converter_v2_1_r_axi3_conv #
(
parameter C_FAMILY = "none",
parameter integer C_AXI_ID_WIDTH = 1,
parameter integer C_AXI_ADDR_WIDTH = 32,
parameter integer C_AXI_DATA_WIDTH = 32,
parameter integer C_AXI_SUPPORTS_USER_SIGNALS = 0,
parameter integer C_AXI_RUSER_WIDTH = 1,
parameter integer C_SUPPORT_SPLITTING = 1,
// Implement transaction splitting logic.
// Disabled whan all connected masters are AXI3 and have same or narrower data width.
parameter integer C_SUPPORT_BURSTS = 1
// Disabled when all connected masters are AxiLite,
// allowing logic to be simplified.
)
(
// System Signals
input wire ACLK,
input wire ARESET,
// Command Interface
input wire cmd_valid,
input wire cmd_split,
output wire cmd_ready,
// Slave Interface Read Data Ports
output wire [C_AXI_ID_WIDTH-1:0] S_AXI_RID,
output wire [C_AXI_DATA_WIDTH-1:0] S_AXI_RDATA,
output wire [2-1:0] S_AXI_RRESP,
output wire S_AXI_RLAST,
output wire [C_AXI_RUSER_WIDTH-1:0] S_AXI_RUSER,
output wire S_AXI_RVALID,
input wire S_AXI_RREADY,
// Master Interface Read Data Ports
input wire [C_AXI_ID_WIDTH-1:0] M_AXI_RID,
input wire [C_AXI_DATA_WIDTH-1:0] M_AXI_RDATA,
input wire [2-1:0] M_AXI_RRESP,
input wire M_AXI_RLAST,
input wire [C_AXI_RUSER_WIDTH-1:0] M_AXI_RUSER,
input wire M_AXI_RVALID,
output wire M_AXI_RREADY
);
/////////////////////////////////////////////////////////////////////////////
// Variables for generating parameter controlled instances.
/////////////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////
// Local params
/////////////////////////////////////////////////////////////////////////////
// Constants for packing levels.
localparam [2-1:0] C_RESP_OKAY = 2'b00;
localparam [2-1:0] C_RESP_EXOKAY = 2'b01;
localparam [2-1:0] C_RESP_SLVERROR = 2'b10;
localparam [2-1:0] C_RESP_DECERR = 2'b11;
/////////////////////////////////////////////////////////////////////////////
// Functions
/////////////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////
// Internal signals
/////////////////////////////////////////////////////////////////////////////
// Throttling help signals.
wire cmd_ready_i;
wire pop_si_data;
wire si_stalling;
// Internal MI-side control signals.
wire M_AXI_RREADY_I;
// Internal signals for SI-side.
wire [C_AXI_ID_WIDTH-1:0] S_AXI_RID_I;
wire [C_AXI_DATA_WIDTH-1:0] S_AXI_RDATA_I;
wire [2-1:0] S_AXI_RRESP_I;
wire S_AXI_RLAST_I;
wire [C_AXI_RUSER_WIDTH-1:0] S_AXI_RUSER_I;
wire S_AXI_RVALID_I;
wire S_AXI_RREADY_I;
/////////////////////////////////////////////////////////////////////////////
// Handle interface handshaking:
//
// Forward data from MI-Side to SI-Side while a command is available. When
// the transaction has completed the command is popped from the Command FIFO.
//
//
/////////////////////////////////////////////////////////////////////////////
// Pop word from SI-side.
assign M_AXI_RREADY_I = ~si_stalling & cmd_valid;
assign M_AXI_RREADY = M_AXI_RREADY_I;
// Indicate when there is data available @ SI-side.
assign S_AXI_RVALID_I = M_AXI_RVALID & cmd_valid;
// Get SI-side data.
assign pop_si_data = S_AXI_RVALID_I & S_AXI_RREADY_I;
// Signal that the command is done (so that it can be poped from command queue).
assign cmd_ready_i = cmd_valid & pop_si_data & M_AXI_RLAST;
assign cmd_ready = cmd_ready_i;
// Detect when MI-side is stalling.
assign si_stalling = S_AXI_RVALID_I & ~S_AXI_RREADY_I;
/////////////////////////////////////////////////////////////////////////////
// Simple AXI signal forwarding:
//
// USER, ID, DATA and RRESP passes through untouched.
//
// LAST has to be filtered to remove any intermediate LAST (due to split
// trasactions). LAST is only removed for the first parts of a split
// transaction. When splitting is unsupported is the LAST filtering completely
// completely removed.
//
/////////////////////////////////////////////////////////////////////////////
// Calculate last, i.e. mask from split transactions.
assign S_AXI_RLAST_I = M_AXI_RLAST &
( ~cmd_split | ( C_SUPPORT_SPLITTING == 0 ) );
// Data is passed through.
assign S_AXI_RID_I = M_AXI_RID;
assign S_AXI_RUSER_I = M_AXI_RUSER;
assign S_AXI_RDATA_I = M_AXI_RDATA;
assign S_AXI_RRESP_I = M_AXI_RRESP;
/////////////////////////////////////////////////////////////////////////////
// SI-side output handling
//
/////////////////////////////////////////////////////////////////////////////
// TODO: registered?
assign S_AXI_RREADY_I = S_AXI_RREADY;
assign S_AXI_RVALID = S_AXI_RVALID_I;
assign S_AXI_RID = S_AXI_RID_I;
assign S_AXI_RDATA = S_AXI_RDATA_I;
assign S_AXI_RRESP = S_AXI_RRESP_I;
assign S_AXI_RLAST = S_AXI_RLAST_I;
assign S_AXI_RUSER = S_AXI_RUSER_I;
endmodule |
module e0 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[1:0],x[31:2]} ^ {x[12:0],x[31:13]} ^ {x[21:0],x[31:22]};
endmodule |
module e1 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[5:0],x[31:6]} ^ {x[10:0],x[31:11]} ^ {x[24:0],x[31:25]};
endmodule |
module ch (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = z ^ (x & (y ^ z));
endmodule |
module maj (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = (x & y) | (z & (x | y));
endmodule |
module s0 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:29] = x[6:4] ^ x[17:15];
assign y[28:0] = {x[3:0], x[31:7]} ^ {x[14:0],x[31:18]} ^ x[31:3];
endmodule |
module s1 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:22] = x[16:7] ^ x[18:9];
assign y[21:0] = {x[6:0],x[31:17]} ^ {x[8:0],x[31:19]} ^ x[31:10];
endmodule |
module e0 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[1:0],x[31:2]} ^ {x[12:0],x[31:13]} ^ {x[21:0],x[31:22]};
endmodule |
module e1 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[5:0],x[31:6]} ^ {x[10:0],x[31:11]} ^ {x[24:0],x[31:25]};
endmodule |
module ch (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = z ^ (x & (y ^ z));
endmodule |
module maj (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = (x & y) | (z & (x | y));
endmodule |
module s0 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:29] = x[6:4] ^ x[17:15];
assign y[28:0] = {x[3:0], x[31:7]} ^ {x[14:0],x[31:18]} ^ x[31:3];
endmodule |
module s1 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:22] = x[16:7] ^ x[18:9];
assign y[21:0] = {x[6:0],x[31:17]} ^ {x[8:0],x[31:19]} ^ x[31:10];
endmodule |
module e0 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[1:0],x[31:2]} ^ {x[12:0],x[31:13]} ^ {x[21:0],x[31:22]};
endmodule |
module e1 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[5:0],x[31:6]} ^ {x[10:0],x[31:11]} ^ {x[24:0],x[31:25]};
endmodule |
module ch (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = z ^ (x & (y ^ z));
endmodule |
module maj (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = (x & y) | (z & (x | y));
endmodule |
module s0 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:29] = x[6:4] ^ x[17:15];
assign y[28:0] = {x[3:0], x[31:7]} ^ {x[14:0],x[31:18]} ^ x[31:3];
endmodule |
module s1 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:22] = x[16:7] ^ x[18:9];
assign y[21:0] = {x[6:0],x[31:17]} ^ {x[8:0],x[31:19]} ^ x[31:10];
endmodule |
module e0 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[1:0],x[31:2]} ^ {x[12:0],x[31:13]} ^ {x[21:0],x[31:22]};
endmodule |
module e1 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[5:0],x[31:6]} ^ {x[10:0],x[31:11]} ^ {x[24:0],x[31:25]};
endmodule |
module ch (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = z ^ (x & (y ^ z));
endmodule |
module maj (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = (x & y) | (z & (x | y));
endmodule |
module s0 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:29] = x[6:4] ^ x[17:15];
assign y[28:0] = {x[3:0], x[31:7]} ^ {x[14:0],x[31:18]} ^ x[31:3];
endmodule |
module s1 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:22] = x[16:7] ^ x[18:9];
assign y[21:0] = {x[6:0],x[31:17]} ^ {x[8:0],x[31:19]} ^ x[31:10];
endmodule |
module e0 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[1:0],x[31:2]} ^ {x[12:0],x[31:13]} ^ {x[21:0],x[31:22]};
endmodule |
module e1 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[5:0],x[31:6]} ^ {x[10:0],x[31:11]} ^ {x[24:0],x[31:25]};
endmodule |
module ch (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = z ^ (x & (y ^ z));
endmodule |
module maj (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = (x & y) | (z & (x | y));
endmodule |
module s0 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:29] = x[6:4] ^ x[17:15];
assign y[28:0] = {x[3:0], x[31:7]} ^ {x[14:0],x[31:18]} ^ x[31:3];
endmodule |
module s1 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:22] = x[16:7] ^ x[18:9];
assign y[21:0] = {x[6:0],x[31:17]} ^ {x[8:0],x[31:19]} ^ x[31:10];
endmodule |
module e0 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[1:0],x[31:2]} ^ {x[12:0],x[31:13]} ^ {x[21:0],x[31:22]};
endmodule |
module e1 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[5:0],x[31:6]} ^ {x[10:0],x[31:11]} ^ {x[24:0],x[31:25]};
endmodule |
module ch (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = z ^ (x & (y ^ z));
endmodule |
module maj (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = (x & y) | (z & (x | y));
endmodule |
module s0 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:29] = x[6:4] ^ x[17:15];
assign y[28:0] = {x[3:0], x[31:7]} ^ {x[14:0],x[31:18]} ^ x[31:3];
endmodule |
module s1 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:22] = x[16:7] ^ x[18:9];
assign y[21:0] = {x[6:0],x[31:17]} ^ {x[8:0],x[31:19]} ^ x[31:10];
endmodule |
module e0 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[1:0],x[31:2]} ^ {x[12:0],x[31:13]} ^ {x[21:0],x[31:22]};
endmodule |
module e1 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[5:0],x[31:6]} ^ {x[10:0],x[31:11]} ^ {x[24:0],x[31:25]};
endmodule |
module ch (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = z ^ (x & (y ^ z));
endmodule |
module maj (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = (x & y) | (z & (x | y));
endmodule |
module s0 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:29] = x[6:4] ^ x[17:15];
assign y[28:0] = {x[3:0], x[31:7]} ^ {x[14:0],x[31:18]} ^ x[31:3];
endmodule |
module s1 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:22] = x[16:7] ^ x[18:9];
assign y[21:0] = {x[6:0],x[31:17]} ^ {x[8:0],x[31:19]} ^ x[31:10];
endmodule |
module e0 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[1:0],x[31:2]} ^ {x[12:0],x[31:13]} ^ {x[21:0],x[31:22]};
endmodule |
module e1 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[5:0],x[31:6]} ^ {x[10:0],x[31:11]} ^ {x[24:0],x[31:25]};
endmodule |
module ch (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = z ^ (x & (y ^ z));
endmodule |
module maj (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = (x & y) | (z & (x | y));
endmodule |
module s0 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:29] = x[6:4] ^ x[17:15];
assign y[28:0] = {x[3:0], x[31:7]} ^ {x[14:0],x[31:18]} ^ x[31:3];
endmodule |
module s1 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:22] = x[16:7] ^ x[18:9];
assign y[21:0] = {x[6:0],x[31:17]} ^ {x[8:0],x[31:19]} ^ x[31:10];
endmodule |
module e0 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[1:0],x[31:2]} ^ {x[12:0],x[31:13]} ^ {x[21:0],x[31:22]};
endmodule |
module e1 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[5:0],x[31:6]} ^ {x[10:0],x[31:11]} ^ {x[24:0],x[31:25]};
endmodule |
module ch (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = z ^ (x & (y ^ z));
endmodule |
module maj (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = (x & y) | (z & (x | y));
endmodule |
module s0 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:29] = x[6:4] ^ x[17:15];
assign y[28:0] = {x[3:0], x[31:7]} ^ {x[14:0],x[31:18]} ^ x[31:3];
endmodule |
module s1 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:22] = x[16:7] ^ x[18:9];
assign y[21:0] = {x[6:0],x[31:17]} ^ {x[8:0],x[31:19]} ^ x[31:10];
endmodule |
module e0 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[1:0],x[31:2]} ^ {x[12:0],x[31:13]} ^ {x[21:0],x[31:22]};
endmodule |
module e1 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[5:0],x[31:6]} ^ {x[10:0],x[31:11]} ^ {x[24:0],x[31:25]};
endmodule |
module ch (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = z ^ (x & (y ^ z));
endmodule |
module maj (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = (x & y) | (z & (x | y));
endmodule |
module s0 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:29] = x[6:4] ^ x[17:15];
assign y[28:0] = {x[3:0], x[31:7]} ^ {x[14:0],x[31:18]} ^ x[31:3];
endmodule |
module s1 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:22] = x[16:7] ^ x[18:9];
assign y[21:0] = {x[6:0],x[31:17]} ^ {x[8:0],x[31:19]} ^ x[31:10];
endmodule |
module e0 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[1:0],x[31:2]} ^ {x[12:0],x[31:13]} ^ {x[21:0],x[31:22]};
endmodule |
module e1 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[5:0],x[31:6]} ^ {x[10:0],x[31:11]} ^ {x[24:0],x[31:25]};
endmodule |
module ch (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = z ^ (x & (y ^ z));
endmodule |
module maj (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = (x & y) | (z & (x | y));
endmodule |
module s0 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:29] = x[6:4] ^ x[17:15];
assign y[28:0] = {x[3:0], x[31:7]} ^ {x[14:0],x[31:18]} ^ x[31:3];
endmodule |
module s1 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:22] = x[16:7] ^ x[18:9];
assign y[21:0] = {x[6:0],x[31:17]} ^ {x[8:0],x[31:19]} ^ x[31:10];
endmodule |
module e0 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[1:0],x[31:2]} ^ {x[12:0],x[31:13]} ^ {x[21:0],x[31:22]};
endmodule |
module e1 (x, y);
input [31:0] x;
output [31:0] y;
assign y = {x[5:0],x[31:6]} ^ {x[10:0],x[31:11]} ^ {x[24:0],x[31:25]};
endmodule |
module ch (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = z ^ (x & (y ^ z));
endmodule |
module maj (x, y, z, o);
input [31:0] x, y, z;
output [31:0] o;
assign o = (x & y) | (z & (x | y));
endmodule |
module s0 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:29] = x[6:4] ^ x[17:15];
assign y[28:0] = {x[3:0], x[31:7]} ^ {x[14:0],x[31:18]} ^ x[31:3];
endmodule |
module s1 (x, y);
input [31:0] x;
output [31:0] y;
assign y[31:22] = x[16:7] ^ x[18:9];
assign y[21:0] = {x[6:0],x[31:17]} ^ {x[8:0],x[31:19]} ^ x[31:10];
endmodule |
module axi_protocol_converter_v2_1_axi_protocol_converter #(
parameter C_FAMILY = "virtex6",
parameter integer C_M_AXI_PROTOCOL = 0,
parameter integer C_S_AXI_PROTOCOL = 0,
parameter integer C_IGNORE_ID = 0,
// 0 = RID/BID are stored by axilite_conv.
// 1 = RID/BID have already been stored in an upstream device, like SASD crossbar.
parameter integer C_AXI_ID_WIDTH = 4,
parameter integer C_AXI_ADDR_WIDTH = 32,
parameter integer C_AXI_DATA_WIDTH = 32,
parameter integer C_AXI_SUPPORTS_WRITE = 1,
parameter integer C_AXI_SUPPORTS_READ = 1,
parameter integer C_AXI_SUPPORTS_USER_SIGNALS = 0,
// 1 = Propagate all USER signals, 0 = Dont propagate.
parameter integer C_AXI_AWUSER_WIDTH = 1,
parameter integer C_AXI_ARUSER_WIDTH = 1,
parameter integer C_AXI_WUSER_WIDTH = 1,
parameter integer C_AXI_RUSER_WIDTH = 1,
parameter integer C_AXI_BUSER_WIDTH = 1,
parameter integer C_TRANSLATION_MODE = 1
// 0 (Unprotected) = Disable all error checking; master is well-behaved.
// 1 (Protection) = Detect SI transaction violations, but perform no splitting.
// AXI4 -> AXI3 must be <= 16 beats; AXI4/3 -> AXI4LITE must be single.
// 2 (Conversion) = Include transaction splitting logic
) (
// Global Signals
input wire aclk,
input wire aresetn,
// Slave Interface Write Address Ports
input wire [C_AXI_ID_WIDTH-1:0] s_axi_awid,
input wire [C_AXI_ADDR_WIDTH-1:0] s_axi_awaddr,
input wire [((C_S_AXI_PROTOCOL == 1) ? 4 : 8)-1:0] s_axi_awlen,
input wire [3-1:0] s_axi_awsize,
input wire [2-1:0] s_axi_awburst,
input wire [((C_S_AXI_PROTOCOL == 1) ? 2 : 1)-1:0] s_axi_awlock,
input wire [4-1:0] s_axi_awcache,
input wire [3-1:0] s_axi_awprot,
input wire [4-1:0] s_axi_awregion,
input wire [4-1:0] s_axi_awqos,
input wire [C_AXI_AWUSER_WIDTH-1:0] s_axi_awuser,
input wire s_axi_awvalid,
output wire s_axi_awready,
// Slave Interface Write Data Ports
input wire [C_AXI_ID_WIDTH-1:0] s_axi_wid,
input wire [C_AXI_DATA_WIDTH-1:0] s_axi_wdata,
input wire [C_AXI_DATA_WIDTH/8-1:0] s_axi_wstrb,
input wire s_axi_wlast,
input wire [C_AXI_WUSER_WIDTH-1:0] s_axi_wuser,
input wire s_axi_wvalid,
output wire s_axi_wready,
// Slave Interface Write Response Ports
output wire [C_AXI_ID_WIDTH-1:0] s_axi_bid,
output wire [2-1:0] s_axi_bresp,
output wire [C_AXI_BUSER_WIDTH-1:0] s_axi_buser,
output wire s_axi_bvalid,
input wire s_axi_bready,
// Slave Interface Read Address Ports
input wire [C_AXI_ID_WIDTH-1:0] s_axi_arid,
input wire [C_AXI_ADDR_WIDTH-1:0] s_axi_araddr,
input wire [((C_S_AXI_PROTOCOL == 1) ? 4 : 8)-1:0] s_axi_arlen,
input wire [3-1:0] s_axi_arsize,
input wire [2-1:0] s_axi_arburst,
input wire [((C_S_AXI_PROTOCOL == 1) ? 2 : 1)-1:0] s_axi_arlock,
input wire [4-1:0] s_axi_arcache,
input wire [3-1:0] s_axi_arprot,
input wire [4-1:0] s_axi_arregion,
input wire [4-1:0] s_axi_arqos,
input wire [C_AXI_ARUSER_WIDTH-1:0] s_axi_aruser,
input wire s_axi_arvalid,
output wire s_axi_arready,
// Slave Interface Read Data Ports
output wire [C_AXI_ID_WIDTH-1:0] s_axi_rid,
output wire [C_AXI_DATA_WIDTH-1:0] s_axi_rdata,
output wire [2-1:0] s_axi_rresp,
output wire s_axi_rlast,
output wire [C_AXI_RUSER_WIDTH-1:0] s_axi_ruser,
output wire s_axi_rvalid,
input wire s_axi_rready,
// Master Interface Write Address Port
output wire [C_AXI_ID_WIDTH-1:0] m_axi_awid,
output wire [C_AXI_ADDR_WIDTH-1:0] m_axi_awaddr,
output wire [((C_M_AXI_PROTOCOL == 1) ? 4 : 8)-1:0] m_axi_awlen,
output wire [3-1:0] m_axi_awsize,
output wire [2-1:0] m_axi_awburst,
output wire [((C_M_AXI_PROTOCOL == 1) ? 2 : 1)-1:0] m_axi_awlock,
output wire [4-1:0] m_axi_awcache,
output wire [3-1:0] m_axi_awprot,
output wire [4-1:0] m_axi_awregion,
output wire [4-1:0] m_axi_awqos,
output wire [C_AXI_AWUSER_WIDTH-1:0] m_axi_awuser,
output wire m_axi_awvalid,
input wire m_axi_awready,
// Master Interface Write Data Ports
output wire [C_AXI_ID_WIDTH-1:0] m_axi_wid,
output wire [C_AXI_DATA_WIDTH-1:0] m_axi_wdata,
output wire [C_AXI_DATA_WIDTH/8-1:0] m_axi_wstrb,
output wire m_axi_wlast,
output wire [C_AXI_WUSER_WIDTH-1:0] m_axi_wuser,
output wire m_axi_wvalid,
input wire m_axi_wready,
// Master Interface Write Response Ports
input wire [C_AXI_ID_WIDTH-1:0] m_axi_bid,
input wire [2-1:0] m_axi_bresp,
input wire [C_AXI_BUSER_WIDTH-1:0] m_axi_buser,
input wire m_axi_bvalid,
output wire m_axi_bready,
// Master Interface Read Address Port
output wire [C_AXI_ID_WIDTH-1:0] m_axi_arid,
output wire [C_AXI_ADDR_WIDTH-1:0] m_axi_araddr,
output wire [((C_M_AXI_PROTOCOL == 1) ? 4 : 8)-1:0] m_axi_arlen,
output wire [3-1:0] m_axi_arsize,
output wire [2-1:0] m_axi_arburst,
output wire [((C_M_AXI_PROTOCOL == 1) ? 2 : 1)-1:0] m_axi_arlock,
output wire [4-1:0] m_axi_arcache,
output wire [3-1:0] m_axi_arprot,
output wire [4-1:0] m_axi_arregion,
output wire [4-1:0] m_axi_arqos,
output wire [C_AXI_ARUSER_WIDTH-1:0] m_axi_aruser,
output wire m_axi_arvalid,
input wire m_axi_arready,
// Master Interface Read Data Ports
input wire [C_AXI_ID_WIDTH-1:0] m_axi_rid,
input wire [C_AXI_DATA_WIDTH-1:0] m_axi_rdata,
input wire [2-1:0] m_axi_rresp,
input wire m_axi_rlast,
input wire [C_AXI_RUSER_WIDTH-1:0] m_axi_ruser,
input wire m_axi_rvalid,
output wire m_axi_rready
);
localparam P_AXI4 = 32'h0;
localparam P_AXI3 = 32'h1;
localparam P_AXILITE = 32'h2;
localparam P_AXILITE_SIZE = (C_AXI_DATA_WIDTH == 32) ? 3'b010 : 3'b011;
localparam P_INCR = 2'b01;
localparam P_DECERR = 2'b11;
localparam P_SLVERR = 2'b10;
localparam integer P_PROTECTION = 1;
localparam integer P_CONVERSION = 2;
wire s_awvalid_i;
wire s_arvalid_i;
wire s_wvalid_i ;
wire s_bready_i ;
wire s_rready_i ;
wire s_awready_i;
wire s_wready_i;
wire s_bvalid_i;
wire [C_AXI_ID_WIDTH-1:0] s_bid_i;
wire [1:0] s_bresp_i;
wire [C_AXI_BUSER_WIDTH-1:0] s_buser_i;
wire s_arready_i;
wire s_rvalid_i;
wire [C_AXI_ID_WIDTH-1:0] s_rid_i;
wire [1:0] s_rresp_i;
wire [C_AXI_RUSER_WIDTH-1:0] s_ruser_i;
wire [C_AXI_DATA_WIDTH-1:0] s_rdata_i;
wire s_rlast_i;
generate
if ((C_M_AXI_PROTOCOL == P_AXILITE) || (C_S_AXI_PROTOCOL == P_AXILITE)) begin : gen_axilite
assign m_axi_awid = 0;
assign m_axi_awlen = 0;
assign m_axi_awsize = P_AXILITE_SIZE;
assign m_axi_awburst = P_INCR;
assign m_axi_awlock = 0;
assign m_axi_awcache = 0;
assign m_axi_awregion = 0;
assign m_axi_awqos = 0;
assign m_axi_awuser = 0;
assign m_axi_wid = 0;
assign m_axi_wlast = 1'b1;
assign m_axi_wuser = 0;
assign m_axi_arid = 0;
assign m_axi_arlen = 0;
assign m_axi_arsize = P_AXILITE_SIZE;
assign m_axi_arburst = P_INCR;
assign m_axi_arlock = 0;
assign m_axi_arcache = 0;
assign m_axi_arregion = 0;
assign m_axi_arqos = 0;
assign m_axi_aruser = 0;
if (((C_IGNORE_ID == 1) && (C_TRANSLATION_MODE != P_CONVERSION)) || (C_S_AXI_PROTOCOL == P_AXILITE)) begin : gen_axilite_passthru
assign m_axi_awaddr = s_axi_awaddr;
assign m_axi_awprot = s_axi_awprot;
assign m_axi_awvalid = s_awvalid_i;
assign s_awready_i = m_axi_awready;
assign m_axi_wdata = s_axi_wdata;
assign m_axi_wstrb = s_axi_wstrb;
assign m_axi_wvalid = s_wvalid_i;
assign s_wready_i = m_axi_wready;
assign s_bid_i = 0;
assign s_bresp_i = m_axi_bresp;
assign s_buser_i = 0;
assign s_bvalid_i = m_axi_bvalid;
assign m_axi_bready = s_bready_i;
assign m_axi_araddr = s_axi_araddr;
assign m_axi_arprot = s_axi_arprot;
assign m_axi_arvalid = s_arvalid_i;
assign s_arready_i = m_axi_arready;
assign s_rid_i = 0;
assign s_rdata_i = m_axi_rdata;
assign s_rresp_i = m_axi_rresp;
assign s_rlast_i = 1'b1;
assign s_ruser_i = 0;
assign s_rvalid_i = m_axi_rvalid;
assign m_axi_rready = s_rready_i;
end else if (C_TRANSLATION_MODE == P_CONVERSION) begin : gen_b2s_conv
assign s_buser_i = {C_AXI_BUSER_WIDTH{1'b0}};
assign s_ruser_i = {C_AXI_RUSER_WIDTH{1'b0}};
axi_protocol_converter_v2_1_b2s #(
.C_S_AXI_PROTOCOL (C_S_AXI_PROTOCOL),
.C_AXI_ID_WIDTH (C_AXI_ID_WIDTH),
.C_AXI_ADDR_WIDTH (C_AXI_ADDR_WIDTH),
.C_AXI_DATA_WIDTH (C_AXI_DATA_WIDTH),
.C_AXI_SUPPORTS_WRITE (C_AXI_SUPPORTS_WRITE),
.C_AXI_SUPPORTS_READ (C_AXI_SUPPORTS_READ)
) axilite_b2s (
.aresetn (aresetn),
.aclk (aclk),
.s_axi_awid (s_axi_awid),
.s_axi_awaddr (s_axi_awaddr),
.s_axi_awlen (s_axi_awlen),
.s_axi_awsize (s_axi_awsize),
.s_axi_awburst (s_axi_awburst),
.s_axi_awprot (s_axi_awprot),
.s_axi_awvalid (s_awvalid_i),
.s_axi_awready (s_awready_i),
.s_axi_wdata (s_axi_wdata),
.s_axi_wstrb (s_axi_wstrb),
.s_axi_wlast (s_axi_wlast),
.s_axi_wvalid (s_wvalid_i),
.s_axi_wready (s_wready_i),
.s_axi_bid (s_bid_i),
.s_axi_bresp (s_bresp_i),
.s_axi_bvalid (s_bvalid_i),
.s_axi_bready (s_bready_i),
.s_axi_arid (s_axi_arid),
.s_axi_araddr (s_axi_araddr),
.s_axi_arlen (s_axi_arlen),
.s_axi_arsize (s_axi_arsize),
.s_axi_arburst (s_axi_arburst),
.s_axi_arprot (s_axi_arprot),
.s_axi_arvalid (s_arvalid_i),
.s_axi_arready (s_arready_i),
.s_axi_rid (s_rid_i),
.s_axi_rdata (s_rdata_i),
.s_axi_rresp (s_rresp_i),
.s_axi_rlast (s_rlast_i),
.s_axi_rvalid (s_rvalid_i),
.s_axi_rready (s_rready_i),
.m_axi_awaddr (m_axi_awaddr),
.m_axi_awprot (m_axi_awprot),
.m_axi_awvalid (m_axi_awvalid),
.m_axi_awready (m_axi_awready),
.m_axi_wdata (m_axi_wdata),
.m_axi_wstrb (m_axi_wstrb),
.m_axi_wvalid (m_axi_wvalid),
.m_axi_wready (m_axi_wready),
.m_axi_bresp (m_axi_bresp),
.m_axi_bvalid (m_axi_bvalid),
.m_axi_bready (m_axi_bready),
.m_axi_araddr (m_axi_araddr),
.m_axi_arprot (m_axi_arprot),
.m_axi_arvalid (m_axi_arvalid),
.m_axi_arready (m_axi_arready),
.m_axi_rdata (m_axi_rdata),
.m_axi_rresp (m_axi_rresp),
.m_axi_rvalid (m_axi_rvalid),
.m_axi_rready (m_axi_rready)
);
end else begin : gen_axilite_conv
axi_protocol_converter_v2_1_axilite_conv #(
.C_FAMILY (C_FAMILY),
.C_AXI_ID_WIDTH (C_AXI_ID_WIDTH),
.C_AXI_ADDR_WIDTH (C_AXI_ADDR_WIDTH),
.C_AXI_DATA_WIDTH (C_AXI_DATA_WIDTH),
.C_AXI_SUPPORTS_WRITE (C_AXI_SUPPORTS_WRITE),
.C_AXI_SUPPORTS_READ (C_AXI_SUPPORTS_READ),
.C_AXI_RUSER_WIDTH (C_AXI_RUSER_WIDTH),
.C_AXI_BUSER_WIDTH (C_AXI_BUSER_WIDTH)
) axilite_conv_inst (
.ARESETN (aresetn),
.ACLK (aclk),
.S_AXI_AWID (s_axi_awid),
.S_AXI_AWADDR (s_axi_awaddr),
.S_AXI_AWPROT (s_axi_awprot),
.S_AXI_AWVALID (s_awvalid_i),
.S_AXI_AWREADY (s_awready_i),
.S_AXI_WDATA (s_axi_wdata),
.S_AXI_WSTRB (s_axi_wstrb),
.S_AXI_WVALID (s_wvalid_i),
.S_AXI_WREADY (s_wready_i),
.S_AXI_BID (s_bid_i),
.S_AXI_BRESP (s_bresp_i),
.S_AXI_BUSER (s_buser_i),
.S_AXI_BVALID (s_bvalid_i),
.S_AXI_BREADY (s_bready_i),
.S_AXI_ARID (s_axi_arid),
.S_AXI_ARADDR (s_axi_araddr),
.S_AXI_ARPROT (s_axi_arprot),
.S_AXI_ARVALID (s_arvalid_i),
.S_AXI_ARREADY (s_arready_i),
.S_AXI_RID (s_rid_i),
.S_AXI_RDATA (s_rdata_i),
.S_AXI_RRESP (s_rresp_i),
.S_AXI_RLAST (s_rlast_i),
.S_AXI_RUSER (s_ruser_i),
.S_AXI_RVALID (s_rvalid_i),
.S_AXI_RREADY (s_rready_i),
.M_AXI_AWADDR (m_axi_awaddr),
.M_AXI_AWPROT (m_axi_awprot),
.M_AXI_AWVALID (m_axi_awvalid),
.M_AXI_AWREADY (m_axi_awready),
.M_AXI_WDATA (m_axi_wdata),
.M_AXI_WSTRB (m_axi_wstrb),
.M_AXI_WVALID (m_axi_wvalid),
.M_AXI_WREADY (m_axi_wready),
.M_AXI_BRESP (m_axi_bresp),
.M_AXI_BVALID (m_axi_bvalid),
.M_AXI_BREADY (m_axi_bready),
.M_AXI_ARADDR (m_axi_araddr),
.M_AXI_ARPROT (m_axi_arprot),
.M_AXI_ARVALID (m_axi_arvalid),
.M_AXI_ARREADY (m_axi_arready),
.M_AXI_RDATA (m_axi_rdata),
.M_AXI_RRESP (m_axi_rresp),
.M_AXI_RVALID (m_axi_rvalid),
.M_AXI_RREADY (m_axi_rready)
);
end
end else if ((C_M_AXI_PROTOCOL == P_AXI3) && (C_S_AXI_PROTOCOL == P_AXI4)) begin : gen_axi4_axi3
axi_protocol_converter_v2_1_axi3_conv #(
.C_FAMILY (C_FAMILY),
.C_AXI_ID_WIDTH (C_AXI_ID_WIDTH),
.C_AXI_ADDR_WIDTH (C_AXI_ADDR_WIDTH),
.C_AXI_DATA_WIDTH (C_AXI_DATA_WIDTH),
.C_AXI_SUPPORTS_USER_SIGNALS (C_AXI_SUPPORTS_USER_SIGNALS),
.C_AXI_AWUSER_WIDTH (C_AXI_AWUSER_WIDTH),
.C_AXI_ARUSER_WIDTH (C_AXI_ARUSER_WIDTH),
.C_AXI_WUSER_WIDTH (C_AXI_WUSER_WIDTH),
.C_AXI_RUSER_WIDTH (C_AXI_RUSER_WIDTH),
.C_AXI_BUSER_WIDTH (C_AXI_BUSER_WIDTH),
.C_AXI_SUPPORTS_WRITE (C_AXI_SUPPORTS_WRITE),
.C_AXI_SUPPORTS_READ (C_AXI_SUPPORTS_READ),
.C_SUPPORT_SPLITTING ((C_TRANSLATION_MODE == P_CONVERSION) ? 1 : 0)
) axi3_conv_inst (
.ARESETN (aresetn),
.ACLK (aclk),
.S_AXI_AWID (s_axi_awid),
.S_AXI_AWADDR (s_axi_awaddr),
.S_AXI_AWLEN (s_axi_awlen),
.S_AXI_AWSIZE (s_axi_awsize),
.S_AXI_AWBURST (s_axi_awburst),
.S_AXI_AWLOCK (s_axi_awlock),
.S_AXI_AWCACHE (s_axi_awcache),
.S_AXI_AWPROT (s_axi_awprot),
.S_AXI_AWQOS (s_axi_awqos),
.S_AXI_AWUSER (s_axi_awuser),
.S_AXI_AWVALID (s_awvalid_i),
.S_AXI_AWREADY (s_awready_i),
.S_AXI_WDATA (s_axi_wdata),
.S_AXI_WSTRB (s_axi_wstrb),
.S_AXI_WLAST (s_axi_wlast),
.S_AXI_WUSER (s_axi_wuser),
.S_AXI_WVALID (s_wvalid_i),
.S_AXI_WREADY (s_wready_i),
.S_AXI_BID (s_bid_i),
.S_AXI_BRESP (s_bresp_i),
.S_AXI_BUSER (s_buser_i),
.S_AXI_BVALID (s_bvalid_i),
.S_AXI_BREADY (s_bready_i),
.S_AXI_ARID (s_axi_arid),
.S_AXI_ARADDR (s_axi_araddr),
.S_AXI_ARLEN (s_axi_arlen),
.S_AXI_ARSIZE (s_axi_arsize),
.S_AXI_ARBURST (s_axi_arburst),
.S_AXI_ARLOCK (s_axi_arlock),
.S_AXI_ARCACHE (s_axi_arcache),
.S_AXI_ARPROT (s_axi_arprot),
.S_AXI_ARQOS (s_axi_arqos),
.S_AXI_ARUSER (s_axi_aruser),
.S_AXI_ARVALID (s_arvalid_i),
.S_AXI_ARREADY (s_arready_i),
.S_AXI_RID (s_rid_i),
.S_AXI_RDATA (s_rdata_i),
.S_AXI_RRESP (s_rresp_i),
.S_AXI_RLAST (s_rlast_i),
.S_AXI_RUSER (s_ruser_i),
.S_AXI_RVALID (s_rvalid_i),
.S_AXI_RREADY (s_rready_i),
.M_AXI_AWID (m_axi_awid),
.M_AXI_AWADDR (m_axi_awaddr),
.M_AXI_AWLEN (m_axi_awlen),
.M_AXI_AWSIZE (m_axi_awsize),
.M_AXI_AWBURST (m_axi_awburst),
.M_AXI_AWLOCK (m_axi_awlock),
.M_AXI_AWCACHE (m_axi_awcache),
.M_AXI_AWPROT (m_axi_awprot),
.M_AXI_AWQOS (m_axi_awqos),
.M_AXI_AWUSER (m_axi_awuser),
.M_AXI_AWVALID (m_axi_awvalid),
.M_AXI_AWREADY (m_axi_awready),
.M_AXI_WID (m_axi_wid),
.M_AXI_WDATA (m_axi_wdata),
.M_AXI_WSTRB (m_axi_wstrb),
.M_AXI_WLAST (m_axi_wlast),
.M_AXI_WUSER (m_axi_wuser),
.M_AXI_WVALID (m_axi_wvalid),
.M_AXI_WREADY (m_axi_wready),
.M_AXI_BID (m_axi_bid),
.M_AXI_BRESP (m_axi_bresp),
.M_AXI_BUSER (m_axi_buser),
.M_AXI_BVALID (m_axi_bvalid),
.M_AXI_BREADY (m_axi_bready),
.M_AXI_ARID (m_axi_arid),
.M_AXI_ARADDR (m_axi_araddr),
.M_AXI_ARLEN (m_axi_arlen),
.M_AXI_ARSIZE (m_axi_arsize),
.M_AXI_ARBURST (m_axi_arburst),
.M_AXI_ARLOCK (m_axi_arlock),
.M_AXI_ARCACHE (m_axi_arcache),
.M_AXI_ARPROT (m_axi_arprot),
.M_AXI_ARQOS (m_axi_arqos),
.M_AXI_ARUSER (m_axi_aruser),
.M_AXI_ARVALID (m_axi_arvalid),
.M_AXI_ARREADY (m_axi_arready),
.M_AXI_RID (m_axi_rid),
.M_AXI_RDATA (m_axi_rdata),
.M_AXI_RRESP (m_axi_rresp),
.M_AXI_RLAST (m_axi_rlast),
.M_AXI_RUSER (m_axi_ruser),
.M_AXI_RVALID (m_axi_rvalid),
.M_AXI_RREADY (m_axi_rready)
);
assign m_axi_awregion = 0;
assign m_axi_arregion = 0;
end else if ((C_S_AXI_PROTOCOL == P_AXI3) && (C_M_AXI_PROTOCOL == P_AXI4)) begin : gen_axi3_axi4
assign m_axi_awid = s_axi_awid;
assign m_axi_awaddr = s_axi_awaddr;
assign m_axi_awlen = {4'h0, s_axi_awlen[3:0]};
assign m_axi_awsize = s_axi_awsize;
assign m_axi_awburst = s_axi_awburst;
assign m_axi_awlock = s_axi_awlock[0];
assign m_axi_awcache = s_axi_awcache;
assign m_axi_awprot = s_axi_awprot;
assign m_axi_awregion = 4'h0;
assign m_axi_awqos = s_axi_awqos;
assign m_axi_awuser = s_axi_awuser;
assign m_axi_awvalid = s_awvalid_i;
assign s_awready_i = m_axi_awready;
assign m_axi_wid = {C_AXI_ID_WIDTH{1'b0}} ;
assign m_axi_wdata = s_axi_wdata;
assign m_axi_wstrb = s_axi_wstrb;
assign m_axi_wlast = s_axi_wlast;
assign m_axi_wuser = s_axi_wuser;
assign m_axi_wvalid = s_wvalid_i;
assign s_wready_i = m_axi_wready;
assign s_bid_i = m_axi_bid;
assign s_bresp_i = m_axi_bresp;
assign s_buser_i = m_axi_buser;
assign s_bvalid_i = m_axi_bvalid;
assign m_axi_bready = s_bready_i;
assign m_axi_arid = s_axi_arid;
assign m_axi_araddr = s_axi_araddr;
assign m_axi_arlen = {4'h0, s_axi_arlen[3:0]};
assign m_axi_arsize = s_axi_arsize;
assign m_axi_arburst = s_axi_arburst;
assign m_axi_arlock = s_axi_arlock[0];
assign m_axi_arcache = s_axi_arcache;
assign m_axi_arprot = s_axi_arprot;
assign m_axi_arregion = 4'h0;
assign m_axi_arqos = s_axi_arqos;
assign m_axi_aruser = s_axi_aruser;
assign m_axi_arvalid = s_arvalid_i;
assign s_arready_i = m_axi_arready;
assign s_rid_i = m_axi_rid;
assign s_rdata_i = m_axi_rdata;
assign s_rresp_i = m_axi_rresp;
assign s_rlast_i = m_axi_rlast;
assign s_ruser_i = m_axi_ruser;
assign s_rvalid_i = m_axi_rvalid;
assign m_axi_rready = s_rready_i;
end else begin :gen_no_conv
assign m_axi_awid = s_axi_awid;
assign m_axi_awaddr = s_axi_awaddr;
assign m_axi_awlen = s_axi_awlen;
assign m_axi_awsize = s_axi_awsize;
assign m_axi_awburst = s_axi_awburst;
assign m_axi_awlock = s_axi_awlock;
assign m_axi_awcache = s_axi_awcache;
assign m_axi_awprot = s_axi_awprot;
assign m_axi_awregion = s_axi_awregion;
assign m_axi_awqos = s_axi_awqos;
assign m_axi_awuser = s_axi_awuser;
assign m_axi_awvalid = s_awvalid_i;
assign s_awready_i = m_axi_awready;
assign m_axi_wid = s_axi_wid;
assign m_axi_wdata = s_axi_wdata;
assign m_axi_wstrb = s_axi_wstrb;
assign m_axi_wlast = s_axi_wlast;
assign m_axi_wuser = s_axi_wuser;
assign m_axi_wvalid = s_wvalid_i;
assign s_wready_i = m_axi_wready;
assign s_bid_i = m_axi_bid;
assign s_bresp_i = m_axi_bresp;
assign s_buser_i = m_axi_buser;
assign s_bvalid_i = m_axi_bvalid;
assign m_axi_bready = s_bready_i;
assign m_axi_arid = s_axi_arid;
assign m_axi_araddr = s_axi_araddr;
assign m_axi_arlen = s_axi_arlen;
assign m_axi_arsize = s_axi_arsize;
assign m_axi_arburst = s_axi_arburst;
assign m_axi_arlock = s_axi_arlock;
assign m_axi_arcache = s_axi_arcache;
assign m_axi_arprot = s_axi_arprot;
assign m_axi_arregion = s_axi_arregion;
assign m_axi_arqos = s_axi_arqos;
assign m_axi_aruser = s_axi_aruser;
assign m_axi_arvalid = s_arvalid_i;
assign s_arready_i = m_axi_arready;
assign s_rid_i = m_axi_rid;
assign s_rdata_i = m_axi_rdata;
assign s_rresp_i = m_axi_rresp;
assign s_rlast_i = m_axi_rlast;
assign s_ruser_i = m_axi_ruser;
assign s_rvalid_i = m_axi_rvalid;
assign m_axi_rready = s_rready_i;
end
if ((C_TRANSLATION_MODE == P_PROTECTION) &&
(((C_S_AXI_PROTOCOL != P_AXILITE) && (C_M_AXI_PROTOCOL == P_AXILITE)) ||
((C_S_AXI_PROTOCOL == P_AXI4) && (C_M_AXI_PROTOCOL == P_AXI3)))) begin : gen_err_detect
wire e_awvalid;
reg e_awvalid_r;
wire e_arvalid;
reg e_arvalid_r;
wire e_wvalid;
wire e_bvalid;
wire e_rvalid;
reg e_awready;
reg e_arready;
wire e_wready;
reg [C_AXI_ID_WIDTH-1:0] e_awid;
reg [C_AXI_ID_WIDTH-1:0] e_arid;
reg [8-1:0] e_arlen;
wire [C_AXI_ID_WIDTH-1:0] e_bid;
wire [C_AXI_ID_WIDTH-1:0] e_rid;
wire e_rlast;
wire w_err;
wire r_err;
wire busy_aw;
wire busy_w;
wire busy_ar;
wire aw_push;
wire aw_pop;
wire w_pop;
wire ar_push;
wire ar_pop;
reg s_awvalid_pending;
reg s_awvalid_en;
reg s_arvalid_en;
reg s_awready_en;
reg s_arready_en;
reg [4:0] aw_cnt;
reg [4:0] ar_cnt;
reg [4:0] w_cnt;
reg w_borrow;
reg err_busy_w;
reg err_busy_r;
assign w_err = (C_M_AXI_PROTOCOL == P_AXILITE) ? (s_axi_awlen != 0) : ((s_axi_awlen>>4) != 0);
assign r_err = (C_M_AXI_PROTOCOL == P_AXILITE) ? (s_axi_arlen != 0) : ((s_axi_arlen>>4) != 0);
assign s_awvalid_i = s_axi_awvalid & s_awvalid_en & ~w_err;
assign e_awvalid = e_awvalid_r & ~busy_aw & ~busy_w;
assign s_arvalid_i = s_axi_arvalid & s_arvalid_en & ~r_err;
assign e_arvalid = e_arvalid_r & ~busy_ar ;
assign s_wvalid_i = s_axi_wvalid & (busy_w | (s_awvalid_pending & ~w_borrow));
assign e_wvalid = s_axi_wvalid & err_busy_w;
assign s_bready_i = s_axi_bready & busy_aw;
assign s_rready_i = s_axi_rready & busy_ar;
assign s_axi_awready = (s_awready_i & s_awready_en) | e_awready;
assign s_axi_wready = (s_wready_i & (busy_w | (s_awvalid_pending & ~w_borrow))) | e_wready;
assign s_axi_bvalid = (s_bvalid_i & busy_aw) | e_bvalid;
assign s_axi_bid = err_busy_w ? e_bid : s_bid_i;
assign s_axi_bresp = err_busy_w ? P_SLVERR : s_bresp_i;
assign s_axi_buser = err_busy_w ? {C_AXI_BUSER_WIDTH{1'b0}} : s_buser_i;
assign s_axi_arready = (s_arready_i & s_arready_en) | e_arready;
assign s_axi_rvalid = (s_rvalid_i & busy_ar) | e_rvalid;
assign s_axi_rid = err_busy_r ? e_rid : s_rid_i;
assign s_axi_rresp = err_busy_r ? P_SLVERR : s_rresp_i;
assign s_axi_ruser = err_busy_r ? {C_AXI_RUSER_WIDTH{1'b0}} : s_ruser_i;
assign s_axi_rdata = err_busy_r ? {C_AXI_DATA_WIDTH{1'b0}} : s_rdata_i;
assign s_axi_rlast = err_busy_r ? e_rlast : s_rlast_i;
assign busy_aw = (aw_cnt != 0);
assign busy_w = (w_cnt != 0);
assign busy_ar = (ar_cnt != 0);
assign aw_push = s_awvalid_i & s_awready_i & s_awready_en;
assign aw_pop = s_bvalid_i & s_bready_i;
assign w_pop = s_wvalid_i & s_wready_i & s_axi_wlast;
assign ar_push = s_arvalid_i & s_arready_i & s_arready_en;
assign ar_pop = s_rvalid_i & s_rready_i & s_rlast_i;
always @(posedge aclk) begin
if (~aresetn) begin
s_awvalid_en <= 1'b0;
s_arvalid_en <= 1'b0;
s_awready_en <= 1'b0;
s_arready_en <= 1'b0;
e_awvalid_r <= 1'b0;
e_arvalid_r <= 1'b0;
e_awready <= 1'b0;
e_arready <= 1'b0;
aw_cnt <= 0;
w_cnt <= 0;
ar_cnt <= 0;
err_busy_w <= 1'b0;
err_busy_r <= 1'b0;
w_borrow <= 1'b0;
s_awvalid_pending <= 1'b0;
end else begin
e_awready <= 1'b0; // One-cycle pulse
if (e_bvalid & s_axi_bready) begin
s_awvalid_en <= 1'b1;
s_awready_en <= 1'b1;
err_busy_w <= 1'b0;
end else if (e_awvalid) begin
e_awvalid_r <= 1'b0;
err_busy_w <= 1'b1;
end else if (s_axi_awvalid & w_err & ~e_awvalid_r & ~err_busy_w) begin
e_awvalid_r <= 1'b1;
e_awready <= ~(s_awready_i & s_awvalid_en); // 1-cycle pulse if awready not already asserted
s_awvalid_en <= 1'b0;
s_awready_en <= 1'b0;
end else if ((&aw_cnt) | (&w_cnt) | aw_push) begin
s_awvalid_en <= 1'b0;
s_awready_en <= 1'b0;
end else if (~err_busy_w & ~e_awvalid_r & ~(s_axi_awvalid & w_err)) begin
s_awvalid_en <= 1'b1;
s_awready_en <= 1'b1;
end
if (aw_push & ~aw_pop) begin
aw_cnt <= aw_cnt + 1;
end else if (~aw_push & aw_pop & (|aw_cnt)) begin
aw_cnt <= aw_cnt - 1;
end
if (aw_push) begin
if (~w_pop & ~w_borrow) begin
w_cnt <= w_cnt + 1;
end
w_borrow <= 1'b0;
end else if (~aw_push & w_pop) begin
if (|w_cnt) begin
w_cnt <= w_cnt - 1;
end else begin
w_borrow <= 1'b1;
end
end
s_awvalid_pending <= s_awvalid_i & ~s_awready_i;
e_arready <= 1'b0; // One-cycle pulse
if (e_rvalid & s_axi_rready & e_rlast) begin
s_arvalid_en <= 1'b1;
s_arready_en <= 1'b1;
err_busy_r <= 1'b0;
end else if (e_arvalid) begin
e_arvalid_r <= 1'b0;
err_busy_r <= 1'b1;
end else if (s_axi_arvalid & r_err & ~e_arvalid_r & ~err_busy_r) begin
e_arvalid_r <= 1'b1;
e_arready <= ~(s_arready_i & s_arvalid_en); // 1-cycle pulse if arready not already asserted
s_arvalid_en <= 1'b0;
s_arready_en <= 1'b0;
end else if ((&ar_cnt) | ar_push) begin
s_arvalid_en <= 1'b0;
s_arready_en <= 1'b0;
end else if (~err_busy_r & ~e_arvalid_r & ~(s_axi_arvalid & r_err)) begin
s_arvalid_en <= 1'b1;
s_arready_en <= 1'b1;
end
if (ar_push & ~ar_pop) begin
ar_cnt <= ar_cnt + 1;
end else if (~ar_push & ar_pop & (|ar_cnt)) begin
ar_cnt <= ar_cnt - 1;
end
end
end
always @(posedge aclk) begin
if (s_axi_awvalid & ~err_busy_w & ~e_awvalid_r ) begin
e_awid <= s_axi_awid;
end
if (s_axi_arvalid & ~err_busy_r & ~e_arvalid_r ) begin
e_arid <= s_axi_arid;
e_arlen <= s_axi_arlen;
end
end
axi_protocol_converter_v2_1_decerr_slave #
(
.C_AXI_ID_WIDTH (C_AXI_ID_WIDTH),
.C_AXI_DATA_WIDTH (C_AXI_DATA_WIDTH),
.C_AXI_RUSER_WIDTH (C_AXI_RUSER_WIDTH),
.C_AXI_BUSER_WIDTH (C_AXI_BUSER_WIDTH),
.C_AXI_PROTOCOL (C_S_AXI_PROTOCOL),
.C_RESP (P_SLVERR),
.C_IGNORE_ID (C_IGNORE_ID)
)
decerr_slave_inst
(
.ACLK (aclk),
.ARESETN (aresetn),
.S_AXI_AWID (e_awid),
.S_AXI_AWVALID (e_awvalid),
.S_AXI_AWREADY (),
.S_AXI_WLAST (s_axi_wlast),
.S_AXI_WVALID (e_wvalid),
.S_AXI_WREADY (e_wready),
.S_AXI_BID (e_bid),
.S_AXI_BRESP (),
.S_AXI_BUSER (),
.S_AXI_BVALID (e_bvalid),
.S_AXI_BREADY (s_axi_bready),
.S_AXI_ARID (e_arid),
.S_AXI_ARLEN (e_arlen),
.S_AXI_ARVALID (e_arvalid),
.S_AXI_ARREADY (),
.S_AXI_RID (e_rid),
.S_AXI_RDATA (),
.S_AXI_RRESP (),
.S_AXI_RUSER (),
.S_AXI_RLAST (e_rlast),
.S_AXI_RVALID (e_rvalid),
.S_AXI_RREADY (s_axi_rready)
);
end else begin : gen_no_err_detect
assign s_awvalid_i = s_axi_awvalid;
assign s_arvalid_i = s_axi_arvalid;
assign s_wvalid_i = s_axi_wvalid;
assign s_bready_i = s_axi_bready;
assign s_rready_i = s_axi_rready;
assign s_axi_awready = s_awready_i;
assign s_axi_wready = s_wready_i;
assign s_axi_bvalid = s_bvalid_i;
assign s_axi_bid = s_bid_i;
assign s_axi_bresp = s_bresp_i;
assign s_axi_buser = s_buser_i;
assign s_axi_arready = s_arready_i;
assign s_axi_rvalid = s_rvalid_i;
assign s_axi_rid = s_rid_i;
assign s_axi_rresp = s_rresp_i;
assign s_axi_ruser = s_ruser_i;
assign s_axi_rdata = s_rdata_i;
assign s_axi_rlast = s_rlast_i;
end // gen_err_detect
endgenerate
endmodule |
module axi_protocol_converter_v2_1_axi_protocol_converter #(
parameter C_FAMILY = "virtex6",
parameter integer C_M_AXI_PROTOCOL = 0,
parameter integer C_S_AXI_PROTOCOL = 0,
parameter integer C_IGNORE_ID = 0,
// 0 = RID/BID are stored by axilite_conv.
// 1 = RID/BID have already been stored in an upstream device, like SASD crossbar.
parameter integer C_AXI_ID_WIDTH = 4,
parameter integer C_AXI_ADDR_WIDTH = 32,
parameter integer C_AXI_DATA_WIDTH = 32,
parameter integer C_AXI_SUPPORTS_WRITE = 1,
parameter integer C_AXI_SUPPORTS_READ = 1,
parameter integer C_AXI_SUPPORTS_USER_SIGNALS = 0,
// 1 = Propagate all USER signals, 0 = Dont propagate.
parameter integer C_AXI_AWUSER_WIDTH = 1,
parameter integer C_AXI_ARUSER_WIDTH = 1,
parameter integer C_AXI_WUSER_WIDTH = 1,
parameter integer C_AXI_RUSER_WIDTH = 1,
parameter integer C_AXI_BUSER_WIDTH = 1,
parameter integer C_TRANSLATION_MODE = 1
// 0 (Unprotected) = Disable all error checking; master is well-behaved.
// 1 (Protection) = Detect SI transaction violations, but perform no splitting.
// AXI4 -> AXI3 must be <= 16 beats; AXI4/3 -> AXI4LITE must be single.
// 2 (Conversion) = Include transaction splitting logic
) (
// Global Signals
input wire aclk,
input wire aresetn,
// Slave Interface Write Address Ports
input wire [C_AXI_ID_WIDTH-1:0] s_axi_awid,
input wire [C_AXI_ADDR_WIDTH-1:0] s_axi_awaddr,
input wire [((C_S_AXI_PROTOCOL == 1) ? 4 : 8)-1:0] s_axi_awlen,
input wire [3-1:0] s_axi_awsize,
input wire [2-1:0] s_axi_awburst,
input wire [((C_S_AXI_PROTOCOL == 1) ? 2 : 1)-1:0] s_axi_awlock,
input wire [4-1:0] s_axi_awcache,
input wire [3-1:0] s_axi_awprot,
input wire [4-1:0] s_axi_awregion,
input wire [4-1:0] s_axi_awqos,
input wire [C_AXI_AWUSER_WIDTH-1:0] s_axi_awuser,
input wire s_axi_awvalid,
output wire s_axi_awready,
// Slave Interface Write Data Ports
input wire [C_AXI_ID_WIDTH-1:0] s_axi_wid,
input wire [C_AXI_DATA_WIDTH-1:0] s_axi_wdata,
input wire [C_AXI_DATA_WIDTH/8-1:0] s_axi_wstrb,
input wire s_axi_wlast,
input wire [C_AXI_WUSER_WIDTH-1:0] s_axi_wuser,
input wire s_axi_wvalid,
output wire s_axi_wready,
// Slave Interface Write Response Ports
output wire [C_AXI_ID_WIDTH-1:0] s_axi_bid,
output wire [2-1:0] s_axi_bresp,
output wire [C_AXI_BUSER_WIDTH-1:0] s_axi_buser,
output wire s_axi_bvalid,
input wire s_axi_bready,
// Slave Interface Read Address Ports
input wire [C_AXI_ID_WIDTH-1:0] s_axi_arid,
input wire [C_AXI_ADDR_WIDTH-1:0] s_axi_araddr,
input wire [((C_S_AXI_PROTOCOL == 1) ? 4 : 8)-1:0] s_axi_arlen,
input wire [3-1:0] s_axi_arsize,
input wire [2-1:0] s_axi_arburst,
input wire [((C_S_AXI_PROTOCOL == 1) ? 2 : 1)-1:0] s_axi_arlock,
input wire [4-1:0] s_axi_arcache,
input wire [3-1:0] s_axi_arprot,
input wire [4-1:0] s_axi_arregion,
input wire [4-1:0] s_axi_arqos,
input wire [C_AXI_ARUSER_WIDTH-1:0] s_axi_aruser,
input wire s_axi_arvalid,
output wire s_axi_arready,
// Slave Interface Read Data Ports
output wire [C_AXI_ID_WIDTH-1:0] s_axi_rid,
output wire [C_AXI_DATA_WIDTH-1:0] s_axi_rdata,
output wire [2-1:0] s_axi_rresp,
output wire s_axi_rlast,
output wire [C_AXI_RUSER_WIDTH-1:0] s_axi_ruser,
output wire s_axi_rvalid,
input wire s_axi_rready,
// Master Interface Write Address Port
output wire [C_AXI_ID_WIDTH-1:0] m_axi_awid,
output wire [C_AXI_ADDR_WIDTH-1:0] m_axi_awaddr,
output wire [((C_M_AXI_PROTOCOL == 1) ? 4 : 8)-1:0] m_axi_awlen,
output wire [3-1:0] m_axi_awsize,
output wire [2-1:0] m_axi_awburst,
output wire [((C_M_AXI_PROTOCOL == 1) ? 2 : 1)-1:0] m_axi_awlock,
output wire [4-1:0] m_axi_awcache,
output wire [3-1:0] m_axi_awprot,
output wire [4-1:0] m_axi_awregion,
output wire [4-1:0] m_axi_awqos,
output wire [C_AXI_AWUSER_WIDTH-1:0] m_axi_awuser,
output wire m_axi_awvalid,
input wire m_axi_awready,
// Master Interface Write Data Ports
output wire [C_AXI_ID_WIDTH-1:0] m_axi_wid,
output wire [C_AXI_DATA_WIDTH-1:0] m_axi_wdata,
output wire [C_AXI_DATA_WIDTH/8-1:0] m_axi_wstrb,
output wire m_axi_wlast,
output wire [C_AXI_WUSER_WIDTH-1:0] m_axi_wuser,
output wire m_axi_wvalid,
input wire m_axi_wready,
// Master Interface Write Response Ports
input wire [C_AXI_ID_WIDTH-1:0] m_axi_bid,
input wire [2-1:0] m_axi_bresp,
input wire [C_AXI_BUSER_WIDTH-1:0] m_axi_buser,
input wire m_axi_bvalid,
output wire m_axi_bready,
// Master Interface Read Address Port
output wire [C_AXI_ID_WIDTH-1:0] m_axi_arid,
output wire [C_AXI_ADDR_WIDTH-1:0] m_axi_araddr,
output wire [((C_M_AXI_PROTOCOL == 1) ? 4 : 8)-1:0] m_axi_arlen,
output wire [3-1:0] m_axi_arsize,
output wire [2-1:0] m_axi_arburst,
output wire [((C_M_AXI_PROTOCOL == 1) ? 2 : 1)-1:0] m_axi_arlock,
output wire [4-1:0] m_axi_arcache,
output wire [3-1:0] m_axi_arprot,
output wire [4-1:0] m_axi_arregion,
output wire [4-1:0] m_axi_arqos,
output wire [C_AXI_ARUSER_WIDTH-1:0] m_axi_aruser,
output wire m_axi_arvalid,
input wire m_axi_arready,
// Master Interface Read Data Ports
input wire [C_AXI_ID_WIDTH-1:0] m_axi_rid,
input wire [C_AXI_DATA_WIDTH-1:0] m_axi_rdata,
input wire [2-1:0] m_axi_rresp,
input wire m_axi_rlast,
input wire [C_AXI_RUSER_WIDTH-1:0] m_axi_ruser,
input wire m_axi_rvalid,
output wire m_axi_rready
);
localparam P_AXI4 = 32'h0;
localparam P_AXI3 = 32'h1;
localparam P_AXILITE = 32'h2;
localparam P_AXILITE_SIZE = (C_AXI_DATA_WIDTH == 32) ? 3'b010 : 3'b011;
localparam P_INCR = 2'b01;
localparam P_DECERR = 2'b11;
localparam P_SLVERR = 2'b10;
localparam integer P_PROTECTION = 1;
localparam integer P_CONVERSION = 2;
wire s_awvalid_i;
wire s_arvalid_i;
wire s_wvalid_i ;
wire s_bready_i ;
wire s_rready_i ;
wire s_awready_i;
wire s_wready_i;
wire s_bvalid_i;
wire [C_AXI_ID_WIDTH-1:0] s_bid_i;
wire [1:0] s_bresp_i;
wire [C_AXI_BUSER_WIDTH-1:0] s_buser_i;
wire s_arready_i;
wire s_rvalid_i;
wire [C_AXI_ID_WIDTH-1:0] s_rid_i;
wire [1:0] s_rresp_i;
wire [C_AXI_RUSER_WIDTH-1:0] s_ruser_i;
wire [C_AXI_DATA_WIDTH-1:0] s_rdata_i;
wire s_rlast_i;
generate
if ((C_M_AXI_PROTOCOL == P_AXILITE) || (C_S_AXI_PROTOCOL == P_AXILITE)) begin : gen_axilite
assign m_axi_awid = 0;
assign m_axi_awlen = 0;
assign m_axi_awsize = P_AXILITE_SIZE;
assign m_axi_awburst = P_INCR;
assign m_axi_awlock = 0;
assign m_axi_awcache = 0;
assign m_axi_awregion = 0;
assign m_axi_awqos = 0;
assign m_axi_awuser = 0;
assign m_axi_wid = 0;
assign m_axi_wlast = 1'b1;
assign m_axi_wuser = 0;
assign m_axi_arid = 0;
assign m_axi_arlen = 0;
assign m_axi_arsize = P_AXILITE_SIZE;
assign m_axi_arburst = P_INCR;
assign m_axi_arlock = 0;
assign m_axi_arcache = 0;
assign m_axi_arregion = 0;
assign m_axi_arqos = 0;
assign m_axi_aruser = 0;
if (((C_IGNORE_ID == 1) && (C_TRANSLATION_MODE != P_CONVERSION)) || (C_S_AXI_PROTOCOL == P_AXILITE)) begin : gen_axilite_passthru
assign m_axi_awaddr = s_axi_awaddr;
assign m_axi_awprot = s_axi_awprot;
assign m_axi_awvalid = s_awvalid_i;
assign s_awready_i = m_axi_awready;
assign m_axi_wdata = s_axi_wdata;
assign m_axi_wstrb = s_axi_wstrb;
assign m_axi_wvalid = s_wvalid_i;
assign s_wready_i = m_axi_wready;
assign s_bid_i = 0;
assign s_bresp_i = m_axi_bresp;
assign s_buser_i = 0;
assign s_bvalid_i = m_axi_bvalid;
assign m_axi_bready = s_bready_i;
assign m_axi_araddr = s_axi_araddr;
assign m_axi_arprot = s_axi_arprot;
assign m_axi_arvalid = s_arvalid_i;
assign s_arready_i = m_axi_arready;
assign s_rid_i = 0;
assign s_rdata_i = m_axi_rdata;
assign s_rresp_i = m_axi_rresp;
assign s_rlast_i = 1'b1;
assign s_ruser_i = 0;
assign s_rvalid_i = m_axi_rvalid;
assign m_axi_rready = s_rready_i;
end else if (C_TRANSLATION_MODE == P_CONVERSION) begin : gen_b2s_conv
assign s_buser_i = {C_AXI_BUSER_WIDTH{1'b0}};
assign s_ruser_i = {C_AXI_RUSER_WIDTH{1'b0}};
axi_protocol_converter_v2_1_b2s #(
.C_S_AXI_PROTOCOL (C_S_AXI_PROTOCOL),
.C_AXI_ID_WIDTH (C_AXI_ID_WIDTH),
.C_AXI_ADDR_WIDTH (C_AXI_ADDR_WIDTH),
.C_AXI_DATA_WIDTH (C_AXI_DATA_WIDTH),
.C_AXI_SUPPORTS_WRITE (C_AXI_SUPPORTS_WRITE),
.C_AXI_SUPPORTS_READ (C_AXI_SUPPORTS_READ)
) axilite_b2s (
.aresetn (aresetn),
.aclk (aclk),
.s_axi_awid (s_axi_awid),
.s_axi_awaddr (s_axi_awaddr),
.s_axi_awlen (s_axi_awlen),
.s_axi_awsize (s_axi_awsize),
.s_axi_awburst (s_axi_awburst),
.s_axi_awprot (s_axi_awprot),
.s_axi_awvalid (s_awvalid_i),
.s_axi_awready (s_awready_i),
.s_axi_wdata (s_axi_wdata),
.s_axi_wstrb (s_axi_wstrb),
.s_axi_wlast (s_axi_wlast),
.s_axi_wvalid (s_wvalid_i),
.s_axi_wready (s_wready_i),
.s_axi_bid (s_bid_i),
.s_axi_bresp (s_bresp_i),
.s_axi_bvalid (s_bvalid_i),
.s_axi_bready (s_bready_i),
.s_axi_arid (s_axi_arid),
.s_axi_araddr (s_axi_araddr),
.s_axi_arlen (s_axi_arlen),
.s_axi_arsize (s_axi_arsize),
.s_axi_arburst (s_axi_arburst),
.s_axi_arprot (s_axi_arprot),
.s_axi_arvalid (s_arvalid_i),
.s_axi_arready (s_arready_i),
.s_axi_rid (s_rid_i),
.s_axi_rdata (s_rdata_i),
.s_axi_rresp (s_rresp_i),
.s_axi_rlast (s_rlast_i),
.s_axi_rvalid (s_rvalid_i),
.s_axi_rready (s_rready_i),
.m_axi_awaddr (m_axi_awaddr),
.m_axi_awprot (m_axi_awprot),
.m_axi_awvalid (m_axi_awvalid),
.m_axi_awready (m_axi_awready),
.m_axi_wdata (m_axi_wdata),
.m_axi_wstrb (m_axi_wstrb),
.m_axi_wvalid (m_axi_wvalid),
.m_axi_wready (m_axi_wready),
.m_axi_bresp (m_axi_bresp),
.m_axi_bvalid (m_axi_bvalid),
.m_axi_bready (m_axi_bready),
.m_axi_araddr (m_axi_araddr),
.m_axi_arprot (m_axi_arprot),
.m_axi_arvalid (m_axi_arvalid),
.m_axi_arready (m_axi_arready),
.m_axi_rdata (m_axi_rdata),
.m_axi_rresp (m_axi_rresp),
.m_axi_rvalid (m_axi_rvalid),
.m_axi_rready (m_axi_rready)
);
end else begin : gen_axilite_conv
axi_protocol_converter_v2_1_axilite_conv #(
.C_FAMILY (C_FAMILY),
.C_AXI_ID_WIDTH (C_AXI_ID_WIDTH),
.C_AXI_ADDR_WIDTH (C_AXI_ADDR_WIDTH),
.C_AXI_DATA_WIDTH (C_AXI_DATA_WIDTH),
.C_AXI_SUPPORTS_WRITE (C_AXI_SUPPORTS_WRITE),
.C_AXI_SUPPORTS_READ (C_AXI_SUPPORTS_READ),
.C_AXI_RUSER_WIDTH (C_AXI_RUSER_WIDTH),
.C_AXI_BUSER_WIDTH (C_AXI_BUSER_WIDTH)
) axilite_conv_inst (
.ARESETN (aresetn),
.ACLK (aclk),
.S_AXI_AWID (s_axi_awid),
.S_AXI_AWADDR (s_axi_awaddr),
.S_AXI_AWPROT (s_axi_awprot),
.S_AXI_AWVALID (s_awvalid_i),
.S_AXI_AWREADY (s_awready_i),
.S_AXI_WDATA (s_axi_wdata),
.S_AXI_WSTRB (s_axi_wstrb),
.S_AXI_WVALID (s_wvalid_i),
.S_AXI_WREADY (s_wready_i),
.S_AXI_BID (s_bid_i),
.S_AXI_BRESP (s_bresp_i),
.S_AXI_BUSER (s_buser_i),
.S_AXI_BVALID (s_bvalid_i),
.S_AXI_BREADY (s_bready_i),
.S_AXI_ARID (s_axi_arid),
.S_AXI_ARADDR (s_axi_araddr),
.S_AXI_ARPROT (s_axi_arprot),
.S_AXI_ARVALID (s_arvalid_i),
.S_AXI_ARREADY (s_arready_i),
.S_AXI_RID (s_rid_i),
.S_AXI_RDATA (s_rdata_i),
.S_AXI_RRESP (s_rresp_i),
.S_AXI_RLAST (s_rlast_i),
.S_AXI_RUSER (s_ruser_i),
.S_AXI_RVALID (s_rvalid_i),
.S_AXI_RREADY (s_rready_i),
.M_AXI_AWADDR (m_axi_awaddr),
.M_AXI_AWPROT (m_axi_awprot),
.M_AXI_AWVALID (m_axi_awvalid),
.M_AXI_AWREADY (m_axi_awready),
.M_AXI_WDATA (m_axi_wdata),
.M_AXI_WSTRB (m_axi_wstrb),
.M_AXI_WVALID (m_axi_wvalid),
.M_AXI_WREADY (m_axi_wready),
.M_AXI_BRESP (m_axi_bresp),
.M_AXI_BVALID (m_axi_bvalid),
.M_AXI_BREADY (m_axi_bready),
.M_AXI_ARADDR (m_axi_araddr),
.M_AXI_ARPROT (m_axi_arprot),
.M_AXI_ARVALID (m_axi_arvalid),
.M_AXI_ARREADY (m_axi_arready),
.M_AXI_RDATA (m_axi_rdata),
.M_AXI_RRESP (m_axi_rresp),
.M_AXI_RVALID (m_axi_rvalid),
.M_AXI_RREADY (m_axi_rready)
);
end
end else if ((C_M_AXI_PROTOCOL == P_AXI3) && (C_S_AXI_PROTOCOL == P_AXI4)) begin : gen_axi4_axi3
axi_protocol_converter_v2_1_axi3_conv #(
.C_FAMILY (C_FAMILY),
.C_AXI_ID_WIDTH (C_AXI_ID_WIDTH),
.C_AXI_ADDR_WIDTH (C_AXI_ADDR_WIDTH),
.C_AXI_DATA_WIDTH (C_AXI_DATA_WIDTH),
.C_AXI_SUPPORTS_USER_SIGNALS (C_AXI_SUPPORTS_USER_SIGNALS),
.C_AXI_AWUSER_WIDTH (C_AXI_AWUSER_WIDTH),
.C_AXI_ARUSER_WIDTH (C_AXI_ARUSER_WIDTH),
.C_AXI_WUSER_WIDTH (C_AXI_WUSER_WIDTH),
.C_AXI_RUSER_WIDTH (C_AXI_RUSER_WIDTH),
.C_AXI_BUSER_WIDTH (C_AXI_BUSER_WIDTH),
.C_AXI_SUPPORTS_WRITE (C_AXI_SUPPORTS_WRITE),
.C_AXI_SUPPORTS_READ (C_AXI_SUPPORTS_READ),
.C_SUPPORT_SPLITTING ((C_TRANSLATION_MODE == P_CONVERSION) ? 1 : 0)
) axi3_conv_inst (
.ARESETN (aresetn),
.ACLK (aclk),
.S_AXI_AWID (s_axi_awid),
.S_AXI_AWADDR (s_axi_awaddr),
.S_AXI_AWLEN (s_axi_awlen),
.S_AXI_AWSIZE (s_axi_awsize),
.S_AXI_AWBURST (s_axi_awburst),
.S_AXI_AWLOCK (s_axi_awlock),
.S_AXI_AWCACHE (s_axi_awcache),
.S_AXI_AWPROT (s_axi_awprot),
.S_AXI_AWQOS (s_axi_awqos),
.S_AXI_AWUSER (s_axi_awuser),
.S_AXI_AWVALID (s_awvalid_i),
.S_AXI_AWREADY (s_awready_i),
.S_AXI_WDATA (s_axi_wdata),
.S_AXI_WSTRB (s_axi_wstrb),
.S_AXI_WLAST (s_axi_wlast),
.S_AXI_WUSER (s_axi_wuser),
.S_AXI_WVALID (s_wvalid_i),
.S_AXI_WREADY (s_wready_i),
.S_AXI_BID (s_bid_i),
.S_AXI_BRESP (s_bresp_i),
.S_AXI_BUSER (s_buser_i),
.S_AXI_BVALID (s_bvalid_i),
.S_AXI_BREADY (s_bready_i),
.S_AXI_ARID (s_axi_arid),
.S_AXI_ARADDR (s_axi_araddr),
.S_AXI_ARLEN (s_axi_arlen),
.S_AXI_ARSIZE (s_axi_arsize),
.S_AXI_ARBURST (s_axi_arburst),
.S_AXI_ARLOCK (s_axi_arlock),
.S_AXI_ARCACHE (s_axi_arcache),
.S_AXI_ARPROT (s_axi_arprot),
.S_AXI_ARQOS (s_axi_arqos),
.S_AXI_ARUSER (s_axi_aruser),
.S_AXI_ARVALID (s_arvalid_i),
.S_AXI_ARREADY (s_arready_i),
.S_AXI_RID (s_rid_i),
.S_AXI_RDATA (s_rdata_i),
.S_AXI_RRESP (s_rresp_i),
.S_AXI_RLAST (s_rlast_i),
.S_AXI_RUSER (s_ruser_i),
.S_AXI_RVALID (s_rvalid_i),
.S_AXI_RREADY (s_rready_i),
.M_AXI_AWID (m_axi_awid),
.M_AXI_AWADDR (m_axi_awaddr),
.M_AXI_AWLEN (m_axi_awlen),
.M_AXI_AWSIZE (m_axi_awsize),
.M_AXI_AWBURST (m_axi_awburst),
.M_AXI_AWLOCK (m_axi_awlock),
.M_AXI_AWCACHE (m_axi_awcache),
.M_AXI_AWPROT (m_axi_awprot),
.M_AXI_AWQOS (m_axi_awqos),
.M_AXI_AWUSER (m_axi_awuser),
.M_AXI_AWVALID (m_axi_awvalid),
.M_AXI_AWREADY (m_axi_awready),
.M_AXI_WID (m_axi_wid),
.M_AXI_WDATA (m_axi_wdata),
.M_AXI_WSTRB (m_axi_wstrb),
.M_AXI_WLAST (m_axi_wlast),
.M_AXI_WUSER (m_axi_wuser),
.M_AXI_WVALID (m_axi_wvalid),
.M_AXI_WREADY (m_axi_wready),
.M_AXI_BID (m_axi_bid),
.M_AXI_BRESP (m_axi_bresp),
.M_AXI_BUSER (m_axi_buser),
.M_AXI_BVALID (m_axi_bvalid),
.M_AXI_BREADY (m_axi_bready),
.M_AXI_ARID (m_axi_arid),
.M_AXI_ARADDR (m_axi_araddr),
.M_AXI_ARLEN (m_axi_arlen),
.M_AXI_ARSIZE (m_axi_arsize),
.M_AXI_ARBURST (m_axi_arburst),
.M_AXI_ARLOCK (m_axi_arlock),
.M_AXI_ARCACHE (m_axi_arcache),
.M_AXI_ARPROT (m_axi_arprot),
.M_AXI_ARQOS (m_axi_arqos),
.M_AXI_ARUSER (m_axi_aruser),
.M_AXI_ARVALID (m_axi_arvalid),
.M_AXI_ARREADY (m_axi_arready),
.M_AXI_RID (m_axi_rid),
.M_AXI_RDATA (m_axi_rdata),
.M_AXI_RRESP (m_axi_rresp),
.M_AXI_RLAST (m_axi_rlast),
.M_AXI_RUSER (m_axi_ruser),
.M_AXI_RVALID (m_axi_rvalid),
.M_AXI_RREADY (m_axi_rready)
);
assign m_axi_awregion = 0;
assign m_axi_arregion = 0;
end else if ((C_S_AXI_PROTOCOL == P_AXI3) && (C_M_AXI_PROTOCOL == P_AXI4)) begin : gen_axi3_axi4
assign m_axi_awid = s_axi_awid;
assign m_axi_awaddr = s_axi_awaddr;
assign m_axi_awlen = {4'h0, s_axi_awlen[3:0]};
assign m_axi_awsize = s_axi_awsize;
assign m_axi_awburst = s_axi_awburst;
assign m_axi_awlock = s_axi_awlock[0];
assign m_axi_awcache = s_axi_awcache;
assign m_axi_awprot = s_axi_awprot;
assign m_axi_awregion = 4'h0;
assign m_axi_awqos = s_axi_awqos;
assign m_axi_awuser = s_axi_awuser;
assign m_axi_awvalid = s_awvalid_i;
assign s_awready_i = m_axi_awready;
assign m_axi_wid = {C_AXI_ID_WIDTH{1'b0}} ;
assign m_axi_wdata = s_axi_wdata;
assign m_axi_wstrb = s_axi_wstrb;
assign m_axi_wlast = s_axi_wlast;
assign m_axi_wuser = s_axi_wuser;
assign m_axi_wvalid = s_wvalid_i;
assign s_wready_i = m_axi_wready;
assign s_bid_i = m_axi_bid;
assign s_bresp_i = m_axi_bresp;
assign s_buser_i = m_axi_buser;
assign s_bvalid_i = m_axi_bvalid;
assign m_axi_bready = s_bready_i;
assign m_axi_arid = s_axi_arid;
assign m_axi_araddr = s_axi_araddr;
assign m_axi_arlen = {4'h0, s_axi_arlen[3:0]};
assign m_axi_arsize = s_axi_arsize;
assign m_axi_arburst = s_axi_arburst;
assign m_axi_arlock = s_axi_arlock[0];
assign m_axi_arcache = s_axi_arcache;
assign m_axi_arprot = s_axi_arprot;
assign m_axi_arregion = 4'h0;
assign m_axi_arqos = s_axi_arqos;
assign m_axi_aruser = s_axi_aruser;
assign m_axi_arvalid = s_arvalid_i;
assign s_arready_i = m_axi_arready;
assign s_rid_i = m_axi_rid;
assign s_rdata_i = m_axi_rdata;
assign s_rresp_i = m_axi_rresp;
assign s_rlast_i = m_axi_rlast;
assign s_ruser_i = m_axi_ruser;
assign s_rvalid_i = m_axi_rvalid;
assign m_axi_rready = s_rready_i;
end else begin :gen_no_conv
assign m_axi_awid = s_axi_awid;
assign m_axi_awaddr = s_axi_awaddr;
assign m_axi_awlen = s_axi_awlen;
assign m_axi_awsize = s_axi_awsize;
assign m_axi_awburst = s_axi_awburst;
assign m_axi_awlock = s_axi_awlock;
assign m_axi_awcache = s_axi_awcache;
assign m_axi_awprot = s_axi_awprot;
assign m_axi_awregion = s_axi_awregion;
assign m_axi_awqos = s_axi_awqos;
assign m_axi_awuser = s_axi_awuser;
assign m_axi_awvalid = s_awvalid_i;
assign s_awready_i = m_axi_awready;
assign m_axi_wid = s_axi_wid;
assign m_axi_wdata = s_axi_wdata;
assign m_axi_wstrb = s_axi_wstrb;
assign m_axi_wlast = s_axi_wlast;
assign m_axi_wuser = s_axi_wuser;
assign m_axi_wvalid = s_wvalid_i;
assign s_wready_i = m_axi_wready;
assign s_bid_i = m_axi_bid;
assign s_bresp_i = m_axi_bresp;
assign s_buser_i = m_axi_buser;
assign s_bvalid_i = m_axi_bvalid;
assign m_axi_bready = s_bready_i;
assign m_axi_arid = s_axi_arid;
assign m_axi_araddr = s_axi_araddr;
assign m_axi_arlen = s_axi_arlen;
assign m_axi_arsize = s_axi_arsize;
assign m_axi_arburst = s_axi_arburst;
assign m_axi_arlock = s_axi_arlock;
assign m_axi_arcache = s_axi_arcache;
assign m_axi_arprot = s_axi_arprot;
assign m_axi_arregion = s_axi_arregion;
assign m_axi_arqos = s_axi_arqos;
assign m_axi_aruser = s_axi_aruser;
assign m_axi_arvalid = s_arvalid_i;
assign s_arready_i = m_axi_arready;
assign s_rid_i = m_axi_rid;
assign s_rdata_i = m_axi_rdata;
assign s_rresp_i = m_axi_rresp;
assign s_rlast_i = m_axi_rlast;
assign s_ruser_i = m_axi_ruser;
assign s_rvalid_i = m_axi_rvalid;
assign m_axi_rready = s_rready_i;
end
if ((C_TRANSLATION_MODE == P_PROTECTION) &&
(((C_S_AXI_PROTOCOL != P_AXILITE) && (C_M_AXI_PROTOCOL == P_AXILITE)) ||
((C_S_AXI_PROTOCOL == P_AXI4) && (C_M_AXI_PROTOCOL == P_AXI3)))) begin : gen_err_detect
wire e_awvalid;
reg e_awvalid_r;
wire e_arvalid;
reg e_arvalid_r;
wire e_wvalid;
wire e_bvalid;
wire e_rvalid;
reg e_awready;
reg e_arready;
wire e_wready;
reg [C_AXI_ID_WIDTH-1:0] e_awid;
reg [C_AXI_ID_WIDTH-1:0] e_arid;
reg [8-1:0] e_arlen;
wire [C_AXI_ID_WIDTH-1:0] e_bid;
wire [C_AXI_ID_WIDTH-1:0] e_rid;
wire e_rlast;
wire w_err;
wire r_err;
wire busy_aw;
wire busy_w;
wire busy_ar;
wire aw_push;
wire aw_pop;
wire w_pop;
wire ar_push;
wire ar_pop;
reg s_awvalid_pending;
reg s_awvalid_en;
reg s_arvalid_en;
reg s_awready_en;
reg s_arready_en;
reg [4:0] aw_cnt;
reg [4:0] ar_cnt;
reg [4:0] w_cnt;
reg w_borrow;
reg err_busy_w;
reg err_busy_r;
assign w_err = (C_M_AXI_PROTOCOL == P_AXILITE) ? (s_axi_awlen != 0) : ((s_axi_awlen>>4) != 0);
assign r_err = (C_M_AXI_PROTOCOL == P_AXILITE) ? (s_axi_arlen != 0) : ((s_axi_arlen>>4) != 0);
assign s_awvalid_i = s_axi_awvalid & s_awvalid_en & ~w_err;
assign e_awvalid = e_awvalid_r & ~busy_aw & ~busy_w;
assign s_arvalid_i = s_axi_arvalid & s_arvalid_en & ~r_err;
assign e_arvalid = e_arvalid_r & ~busy_ar ;
assign s_wvalid_i = s_axi_wvalid & (busy_w | (s_awvalid_pending & ~w_borrow));
assign e_wvalid = s_axi_wvalid & err_busy_w;
assign s_bready_i = s_axi_bready & busy_aw;
assign s_rready_i = s_axi_rready & busy_ar;
assign s_axi_awready = (s_awready_i & s_awready_en) | e_awready;
assign s_axi_wready = (s_wready_i & (busy_w | (s_awvalid_pending & ~w_borrow))) | e_wready;
assign s_axi_bvalid = (s_bvalid_i & busy_aw) | e_bvalid;
assign s_axi_bid = err_busy_w ? e_bid : s_bid_i;
assign s_axi_bresp = err_busy_w ? P_SLVERR : s_bresp_i;
assign s_axi_buser = err_busy_w ? {C_AXI_BUSER_WIDTH{1'b0}} : s_buser_i;
assign s_axi_arready = (s_arready_i & s_arready_en) | e_arready;
assign s_axi_rvalid = (s_rvalid_i & busy_ar) | e_rvalid;
assign s_axi_rid = err_busy_r ? e_rid : s_rid_i;
assign s_axi_rresp = err_busy_r ? P_SLVERR : s_rresp_i;
assign s_axi_ruser = err_busy_r ? {C_AXI_RUSER_WIDTH{1'b0}} : s_ruser_i;
assign s_axi_rdata = err_busy_r ? {C_AXI_DATA_WIDTH{1'b0}} : s_rdata_i;
assign s_axi_rlast = err_busy_r ? e_rlast : s_rlast_i;
assign busy_aw = (aw_cnt != 0);
assign busy_w = (w_cnt != 0);
assign busy_ar = (ar_cnt != 0);
assign aw_push = s_awvalid_i & s_awready_i & s_awready_en;
assign aw_pop = s_bvalid_i & s_bready_i;
assign w_pop = s_wvalid_i & s_wready_i & s_axi_wlast;
assign ar_push = s_arvalid_i & s_arready_i & s_arready_en;
assign ar_pop = s_rvalid_i & s_rready_i & s_rlast_i;
always @(posedge aclk) begin
if (~aresetn) begin
s_awvalid_en <= 1'b0;
s_arvalid_en <= 1'b0;
s_awready_en <= 1'b0;
s_arready_en <= 1'b0;
e_awvalid_r <= 1'b0;
e_arvalid_r <= 1'b0;
e_awready <= 1'b0;
e_arready <= 1'b0;
aw_cnt <= 0;
w_cnt <= 0;
ar_cnt <= 0;
err_busy_w <= 1'b0;
err_busy_r <= 1'b0;
w_borrow <= 1'b0;
s_awvalid_pending <= 1'b0;
end else begin
e_awready <= 1'b0; // One-cycle pulse
if (e_bvalid & s_axi_bready) begin
s_awvalid_en <= 1'b1;
s_awready_en <= 1'b1;
err_busy_w <= 1'b0;
end else if (e_awvalid) begin
e_awvalid_r <= 1'b0;
err_busy_w <= 1'b1;
end else if (s_axi_awvalid & w_err & ~e_awvalid_r & ~err_busy_w) begin
e_awvalid_r <= 1'b1;
e_awready <= ~(s_awready_i & s_awvalid_en); // 1-cycle pulse if awready not already asserted
s_awvalid_en <= 1'b0;
s_awready_en <= 1'b0;
end else if ((&aw_cnt) | (&w_cnt) | aw_push) begin
s_awvalid_en <= 1'b0;
s_awready_en <= 1'b0;
end else if (~err_busy_w & ~e_awvalid_r & ~(s_axi_awvalid & w_err)) begin
s_awvalid_en <= 1'b1;
s_awready_en <= 1'b1;
end
if (aw_push & ~aw_pop) begin
aw_cnt <= aw_cnt + 1;
end else if (~aw_push & aw_pop & (|aw_cnt)) begin
aw_cnt <= aw_cnt - 1;
end
if (aw_push) begin
if (~w_pop & ~w_borrow) begin
w_cnt <= w_cnt + 1;
end
w_borrow <= 1'b0;
end else if (~aw_push & w_pop) begin
if (|w_cnt) begin
w_cnt <= w_cnt - 1;
end else begin
w_borrow <= 1'b1;
end
end
s_awvalid_pending <= s_awvalid_i & ~s_awready_i;
e_arready <= 1'b0; // One-cycle pulse
if (e_rvalid & s_axi_rready & e_rlast) begin
s_arvalid_en <= 1'b1;
s_arready_en <= 1'b1;
err_busy_r <= 1'b0;
end else if (e_arvalid) begin
e_arvalid_r <= 1'b0;
err_busy_r <= 1'b1;
end else if (s_axi_arvalid & r_err & ~e_arvalid_r & ~err_busy_r) begin
e_arvalid_r <= 1'b1;
e_arready <= ~(s_arready_i & s_arvalid_en); // 1-cycle pulse if arready not already asserted
s_arvalid_en <= 1'b0;
s_arready_en <= 1'b0;
end else if ((&ar_cnt) | ar_push) begin
s_arvalid_en <= 1'b0;
s_arready_en <= 1'b0;
end else if (~err_busy_r & ~e_arvalid_r & ~(s_axi_arvalid & r_err)) begin
s_arvalid_en <= 1'b1;
s_arready_en <= 1'b1;
end
if (ar_push & ~ar_pop) begin
ar_cnt <= ar_cnt + 1;
end else if (~ar_push & ar_pop & (|ar_cnt)) begin
ar_cnt <= ar_cnt - 1;
end
end
end
always @(posedge aclk) begin
if (s_axi_awvalid & ~err_busy_w & ~e_awvalid_r ) begin
e_awid <= s_axi_awid;
end
if (s_axi_arvalid & ~err_busy_r & ~e_arvalid_r ) begin
e_arid <= s_axi_arid;
e_arlen <= s_axi_arlen;
end
end
axi_protocol_converter_v2_1_decerr_slave #
(
.C_AXI_ID_WIDTH (C_AXI_ID_WIDTH),
.C_AXI_DATA_WIDTH (C_AXI_DATA_WIDTH),
.C_AXI_RUSER_WIDTH (C_AXI_RUSER_WIDTH),
.C_AXI_BUSER_WIDTH (C_AXI_BUSER_WIDTH),
.C_AXI_PROTOCOL (C_S_AXI_PROTOCOL),
.C_RESP (P_SLVERR),
.C_IGNORE_ID (C_IGNORE_ID)
)
decerr_slave_inst
(
.ACLK (aclk),
.ARESETN (aresetn),
.S_AXI_AWID (e_awid),
.S_AXI_AWVALID (e_awvalid),
.S_AXI_AWREADY (),
.S_AXI_WLAST (s_axi_wlast),
.S_AXI_WVALID (e_wvalid),
.S_AXI_WREADY (e_wready),
.S_AXI_BID (e_bid),
.S_AXI_BRESP (),
.S_AXI_BUSER (),
.S_AXI_BVALID (e_bvalid),
.S_AXI_BREADY (s_axi_bready),
.S_AXI_ARID (e_arid),
.S_AXI_ARLEN (e_arlen),
.S_AXI_ARVALID (e_arvalid),
.S_AXI_ARREADY (),
.S_AXI_RID (e_rid),
.S_AXI_RDATA (),
.S_AXI_RRESP (),
.S_AXI_RUSER (),
.S_AXI_RLAST (e_rlast),
.S_AXI_RVALID (e_rvalid),
.S_AXI_RREADY (s_axi_rready)
);
end else begin : gen_no_err_detect
assign s_awvalid_i = s_axi_awvalid;
assign s_arvalid_i = s_axi_arvalid;
assign s_wvalid_i = s_axi_wvalid;
assign s_bready_i = s_axi_bready;
assign s_rready_i = s_axi_rready;
assign s_axi_awready = s_awready_i;
assign s_axi_wready = s_wready_i;
assign s_axi_bvalid = s_bvalid_i;
assign s_axi_bid = s_bid_i;
assign s_axi_bresp = s_bresp_i;
assign s_axi_buser = s_buser_i;
assign s_axi_arready = s_arready_i;
assign s_axi_rvalid = s_rvalid_i;
assign s_axi_rid = s_rid_i;
assign s_axi_rresp = s_rresp_i;
assign s_axi_ruser = s_ruser_i;
assign s_axi_rdata = s_rdata_i;
assign s_axi_rlast = s_rlast_i;
end // gen_err_detect
endgenerate
endmodule |
module
input wire load_a_i,
input wire load_b_i,
input wire [EW-1:0] Data_A_i,
input wire [EW-1:0] Data_B_i,
input wire Add_Subt_i,
///////////////////////////////////////////////////////////////////77
output wire [EW-1:0] Data_Result_o,
output wire Overflow_flag_o,
output wire Underflow_flag_o
);
//wire [EW-1:0] Data_B;
wire [EW:0] Data_S;
/////////////////////////////////////////7
//genvar j;
//for (j=0; j<EW; j=j+1)begin
// assign Data_B[j] = PreData_B_i[j] ^ Add_Subt_i;
//end
/////////////////////////////////////////
add_sub_carry_out #(.W(EW)) exp_add_subt(
.op_mode (Add_Subt_i),
.Data_A (Data_A_i),
.Data_B (Data_B_i),
.Data_S (Data_S)
);
//assign Overflow_flag_o = 1'b0;
//assign Underflow_flag_o = 1'b0;
Comparators #(.W_Exp(EW+1)) array_comparators(
.exp(Data_S),
.overflow(Overflow_flag),
.underflow(Underflow_flag)
);
RegisterAdd #(.W(EW)) exp_result(
.clk (clk),
.rst (rst),
.load (load_a_i),
.D (Data_S[EW-1:0]),
.Q (Data_Result_o)
);
RegisterAdd #(.W(1)) Overflow (
.clk(clk),
.rst(rst),
.load(load_a_i),
.D(Overflow_flag),
.Q(Overflow_flag_o)
);
RegisterAdd #(.W(1)) Underflow (
.clk(clk),
.rst(rst),
.load(load_b_i),
.D(Underflow_flag),
.Q(Underflow_flag_o)
);
endmodule |
module vga (
// Wishbone signals
input wb_clk_i, // 25 Mhz VDU clock
input wb_rst_i,
input [15:0] wb_dat_i,
output [15:0] wb_dat_o,
input [16:1] wb_adr_i,
input wb_we_i,
input wb_tga_i,
input [ 1:0] wb_sel_i,
input wb_stb_i,
input wb_cyc_i,
output wb_ack_o,
// VGA pad signals
output [ 3:0] vga_red_o,
output [ 3:0] vga_green_o,
output [ 3:0] vga_blue_o,
output horiz_sync,
output vert_sync,
// CSR SRAM master interface
output [17:1] csrm_adr_o,
output [ 1:0] csrm_sel_o,
output csrm_we_o,
output [15:0] csrm_dat_o,
input [15:0] csrm_dat_i
);
// Registers and nets
//
// csr address
reg [17:1] csr_adr_i;
reg csr_stb_i;
// Config wires
wire [15:0] conf_wb_dat_o;
wire conf_wb_ack_o;
// Mem wires
wire [15:0] mem_wb_dat_o;
wire mem_wb_ack_o;
// LCD wires
wire [17:1] csr_adr_o;
wire [15:0] csr_dat_i;
wire csr_stb_o;
wire v_retrace;
wire vh_retrace;
wire w_vert_sync;
// VGA configuration registers
wire shift_reg1;
wire graphics_alpha;
wire memory_mapping1;
wire [ 1:0] write_mode;
wire [ 1:0] raster_op;
wire read_mode;
wire [ 7:0] bitmask;
wire [ 3:0] set_reset;
wire [ 3:0] enable_set_reset;
wire [ 3:0] map_mask;
wire x_dotclockdiv2;
wire chain_four;
wire [ 1:0] read_map_select;
wire [ 3:0] color_compare;
wire [ 3:0] color_dont_care;
// Wishbone master to SRAM
wire [17:1] wbm_adr_o;
wire [ 1:0] wbm_sel_o;
wire wbm_we_o;
wire [15:0] wbm_dat_o;
wire [15:0] wbm_dat_i;
wire wbm_stb_o;
wire wbm_ack_i;
wire stb;
// CRT wires
wire [ 5:0] cur_start;
wire [ 5:0] cur_end;
wire [15:0] start_addr;
wire [ 4:0] vcursor;
wire [ 6:0] hcursor;
wire [ 6:0] horiz_total;
wire [ 6:0] end_horiz;
wire [ 6:0] st_hor_retr;
wire [ 4:0] end_hor_retr;
wire [ 9:0] vert_total;
wire [ 9:0] end_vert;
wire [ 9:0] st_ver_retr;
wire [ 3:0] end_ver_retr;
// attribute_ctrl wires
wire [3:0] pal_addr;
wire pal_we;
wire [7:0] pal_read;
wire [7:0] pal_write;
// dac_regs wires
wire dac_we;
wire [1:0] dac_read_data_cycle;
wire [7:0] dac_read_data_register;
wire [3:0] dac_read_data;
wire [1:0] dac_write_data_cycle;
wire [7:0] dac_write_data_register;
wire [3:0] dac_write_data;
// Module instances
//
vga_config_iface config_iface (
.wb_clk_i (wb_clk_i),
.wb_rst_i (wb_rst_i),
.wb_dat_i (wb_dat_i),
.wb_dat_o (conf_wb_dat_o),
.wb_adr_i (wb_adr_i[4:1]),
.wb_we_i (wb_we_i),
.wb_sel_i (wb_sel_i),
.wb_stb_i (stb & wb_tga_i),
.wb_ack_o (conf_wb_ack_o),
.shift_reg1 (shift_reg1),
.graphics_alpha (graphics_alpha),
.memory_mapping1 (memory_mapping1),
.write_mode (write_mode),
.raster_op (raster_op),
.read_mode (read_mode),
.bitmask (bitmask),
.set_reset (set_reset),
.enable_set_reset (enable_set_reset),
.map_mask (map_mask),
.x_dotclockdiv2 (x_dotclockdiv2),
.chain_four (chain_four),
.read_map_select (read_map_select),
.color_compare (color_compare),
.color_dont_care (color_dont_care),
.pal_addr (pal_addr),
.pal_we (pal_we),
.pal_read (pal_read),
.pal_write (pal_write),
.dac_we (dac_we),
.dac_read_data_cycle (dac_read_data_cycle),
.dac_read_data_register (dac_read_data_register),
.dac_read_data (dac_read_data),
.dac_write_data_cycle (dac_write_data_cycle),
.dac_write_data_register (dac_write_data_register),
.dac_write_data (dac_write_data),
.cur_start (cur_start),
.cur_end (cur_end),
.start_addr (start_addr),
.vcursor (vcursor),
.hcursor (hcursor),
.horiz_total (horiz_total),
.end_horiz (end_horiz),
.st_hor_retr (st_hor_retr),
.end_hor_retr (end_hor_retr),
.vert_total (vert_total),
.end_vert (end_vert),
.st_ver_retr (st_ver_retr),
.end_ver_retr (end_ver_retr),
.v_retrace (v_retrace),
.vh_retrace (vh_retrace)
);
vga_lcd lcd (
.clk (wb_clk_i),
.rst (wb_rst_i),
.shift_reg1 (shift_reg1),
.graphics_alpha (graphics_alpha),
.pal_addr (pal_addr),
.pal_we (pal_we),
.pal_read (pal_read),
.pal_write (pal_write),
.dac_we (dac_we),
.dac_read_data_cycle (dac_read_data_cycle),
.dac_read_data_register (dac_read_data_register),
.dac_read_data (dac_read_data),
.dac_write_data_cycle (dac_write_data_cycle),
.dac_write_data_register (dac_write_data_register),
.dac_write_data (dac_write_data),
.csr_adr_o (csr_adr_o),
.csr_dat_i (csr_dat_i),
.csr_stb_o (csr_stb_o),
.vga_red_o (vga_red_o),
.vga_green_o (vga_green_o),
.vga_blue_o (vga_blue_o),
.horiz_sync (horiz_sync),
.vert_sync (w_vert_sync),
.cur_start (cur_start),
.cur_end (cur_end),
.vcursor (vcursor),
.hcursor (hcursor),
.horiz_total (horiz_total),
.end_horiz (end_horiz),
.st_hor_retr (st_hor_retr),
.end_hor_retr (end_hor_retr),
.vert_total (vert_total),
.end_vert (end_vert),
.st_ver_retr (st_ver_retr),
.end_ver_retr (end_ver_retr),
.x_dotclockdiv2 (x_dotclockdiv2),
.v_retrace (v_retrace),
.vh_retrace (vh_retrace)
);
vga_cpu_mem_iface cpu_mem_iface (
.wb_clk_i (wb_clk_i),
.wb_rst_i (wb_rst_i),
.wbs_adr_i (wb_adr_i),
.wbs_sel_i (wb_sel_i),
.wbs_we_i (wb_we_i),
.wbs_dat_i (wb_dat_i),
.wbs_dat_o (mem_wb_dat_o),
.wbs_stb_i (stb & !wb_tga_i),
.wbs_ack_o (mem_wb_ack_o),
.wbm_adr_o (wbm_adr_o),
.wbm_sel_o (wbm_sel_o),
.wbm_we_o (wbm_we_o),
.wbm_dat_o (wbm_dat_o),
.wbm_dat_i (wbm_dat_i),
.wbm_stb_o (wbm_stb_o),
.wbm_ack_i (wbm_ack_i),
.chain_four (chain_four),
.memory_mapping1 (memory_mapping1),
.write_mode (write_mode),
.raster_op (raster_op),
.read_mode (read_mode),
.bitmask (bitmask),
.set_reset (set_reset),
.enable_set_reset (enable_set_reset),
.map_mask (map_mask),
.read_map_select (read_map_select),
.color_compare (color_compare),
.color_dont_care (color_dont_care)
);
vga_mem_arbitrer mem_arbitrer (
.clk_i (wb_clk_i),
.rst_i (wb_rst_i),
.wb_adr_i (wbm_adr_o),
.wb_sel_i (wbm_sel_o),
.wb_we_i (wbm_we_o),
.wb_dat_i (wbm_dat_o),
.wb_dat_o (wbm_dat_i),
.wb_stb_i (wbm_stb_o),
.wb_ack_o (wbm_ack_i),
.csr_adr_i (csr_adr_i),
.csr_dat_o (csr_dat_i),
.csr_stb_i (csr_stb_i),
.csrm_adr_o (csrm_adr_o),
.csrm_sel_o (csrm_sel_o),
.csrm_we_o (csrm_we_o),
.csrm_dat_o (csrm_dat_o),
.csrm_dat_i (csrm_dat_i)
);
// Continous assignments
assign wb_dat_o = wb_tga_i ? conf_wb_dat_o : mem_wb_dat_o;
assign wb_ack_o = wb_tga_i ? conf_wb_ack_o : mem_wb_ack_o;
assign stb = wb_stb_i & wb_cyc_i;
assign vert_sync = ~graphics_alpha ^ w_vert_sync;
// Behaviour
// csr_adr_i
always @(posedge wb_clk_i)
csr_adr_i <= wb_rst_i ? 17'h0 : csr_adr_o + start_addr[15:1];
// csr_stb_i
always @(posedge wb_clk_i)
csr_stb_i <= wb_rst_i ? 1'b0 : csr_stb_o;
endmodule |
module vga (
// Wishbone signals
input wb_clk_i, // 25 Mhz VDU clock
input wb_rst_i,
input [15:0] wb_dat_i,
output [15:0] wb_dat_o,
input [16:1] wb_adr_i,
input wb_we_i,
input wb_tga_i,
input [ 1:0] wb_sel_i,
input wb_stb_i,
input wb_cyc_i,
output wb_ack_o,
// VGA pad signals
output [ 3:0] vga_red_o,
output [ 3:0] vga_green_o,
output [ 3:0] vga_blue_o,
output horiz_sync,
output vert_sync,
// CSR SRAM master interface
output [17:1] csrm_adr_o,
output [ 1:0] csrm_sel_o,
output csrm_we_o,
output [15:0] csrm_dat_o,
input [15:0] csrm_dat_i
);
// Registers and nets
//
// csr address
reg [17:1] csr_adr_i;
reg csr_stb_i;
// Config wires
wire [15:0] conf_wb_dat_o;
wire conf_wb_ack_o;
// Mem wires
wire [15:0] mem_wb_dat_o;
wire mem_wb_ack_o;
// LCD wires
wire [17:1] csr_adr_o;
wire [15:0] csr_dat_i;
wire csr_stb_o;
wire v_retrace;
wire vh_retrace;
wire w_vert_sync;
// VGA configuration registers
wire shift_reg1;
wire graphics_alpha;
wire memory_mapping1;
wire [ 1:0] write_mode;
wire [ 1:0] raster_op;
wire read_mode;
wire [ 7:0] bitmask;
wire [ 3:0] set_reset;
wire [ 3:0] enable_set_reset;
wire [ 3:0] map_mask;
wire x_dotclockdiv2;
wire chain_four;
wire [ 1:0] read_map_select;
wire [ 3:0] color_compare;
wire [ 3:0] color_dont_care;
// Wishbone master to SRAM
wire [17:1] wbm_adr_o;
wire [ 1:0] wbm_sel_o;
wire wbm_we_o;
wire [15:0] wbm_dat_o;
wire [15:0] wbm_dat_i;
wire wbm_stb_o;
wire wbm_ack_i;
wire stb;
// CRT wires
wire [ 5:0] cur_start;
wire [ 5:0] cur_end;
wire [15:0] start_addr;
wire [ 4:0] vcursor;
wire [ 6:0] hcursor;
wire [ 6:0] horiz_total;
wire [ 6:0] end_horiz;
wire [ 6:0] st_hor_retr;
wire [ 4:0] end_hor_retr;
wire [ 9:0] vert_total;
wire [ 9:0] end_vert;
wire [ 9:0] st_ver_retr;
wire [ 3:0] end_ver_retr;
// attribute_ctrl wires
wire [3:0] pal_addr;
wire pal_we;
wire [7:0] pal_read;
wire [7:0] pal_write;
// dac_regs wires
wire dac_we;
wire [1:0] dac_read_data_cycle;
wire [7:0] dac_read_data_register;
wire [3:0] dac_read_data;
wire [1:0] dac_write_data_cycle;
wire [7:0] dac_write_data_register;
wire [3:0] dac_write_data;
// Module instances
//
vga_config_iface config_iface (
.wb_clk_i (wb_clk_i),
.wb_rst_i (wb_rst_i),
.wb_dat_i (wb_dat_i),
.wb_dat_o (conf_wb_dat_o),
.wb_adr_i (wb_adr_i[4:1]),
.wb_we_i (wb_we_i),
.wb_sel_i (wb_sel_i),
.wb_stb_i (stb & wb_tga_i),
.wb_ack_o (conf_wb_ack_o),
.shift_reg1 (shift_reg1),
.graphics_alpha (graphics_alpha),
.memory_mapping1 (memory_mapping1),
.write_mode (write_mode),
.raster_op (raster_op),
.read_mode (read_mode),
.bitmask (bitmask),
.set_reset (set_reset),
.enable_set_reset (enable_set_reset),
.map_mask (map_mask),
.x_dotclockdiv2 (x_dotclockdiv2),
.chain_four (chain_four),
.read_map_select (read_map_select),
.color_compare (color_compare),
.color_dont_care (color_dont_care),
.pal_addr (pal_addr),
.pal_we (pal_we),
.pal_read (pal_read),
.pal_write (pal_write),
.dac_we (dac_we),
.dac_read_data_cycle (dac_read_data_cycle),
.dac_read_data_register (dac_read_data_register),
.dac_read_data (dac_read_data),
.dac_write_data_cycle (dac_write_data_cycle),
.dac_write_data_register (dac_write_data_register),
.dac_write_data (dac_write_data),
.cur_start (cur_start),
.cur_end (cur_end),
.start_addr (start_addr),
.vcursor (vcursor),
.hcursor (hcursor),
.horiz_total (horiz_total),
.end_horiz (end_horiz),
.st_hor_retr (st_hor_retr),
.end_hor_retr (end_hor_retr),
.vert_total (vert_total),
.end_vert (end_vert),
.st_ver_retr (st_ver_retr),
.end_ver_retr (end_ver_retr),
.v_retrace (v_retrace),
.vh_retrace (vh_retrace)
);
vga_lcd lcd (
.clk (wb_clk_i),
.rst (wb_rst_i),
.shift_reg1 (shift_reg1),
.graphics_alpha (graphics_alpha),
.pal_addr (pal_addr),
.pal_we (pal_we),
.pal_read (pal_read),
.pal_write (pal_write),
.dac_we (dac_we),
.dac_read_data_cycle (dac_read_data_cycle),
.dac_read_data_register (dac_read_data_register),
.dac_read_data (dac_read_data),
.dac_write_data_cycle (dac_write_data_cycle),
.dac_write_data_register (dac_write_data_register),
.dac_write_data (dac_write_data),
.csr_adr_o (csr_adr_o),
.csr_dat_i (csr_dat_i),
.csr_stb_o (csr_stb_o),
.vga_red_o (vga_red_o),
.vga_green_o (vga_green_o),
.vga_blue_o (vga_blue_o),
.horiz_sync (horiz_sync),
.vert_sync (w_vert_sync),
.cur_start (cur_start),
.cur_end (cur_end),
.vcursor (vcursor),
.hcursor (hcursor),
.horiz_total (horiz_total),
.end_horiz (end_horiz),
.st_hor_retr (st_hor_retr),
.end_hor_retr (end_hor_retr),
.vert_total (vert_total),
.end_vert (end_vert),
.st_ver_retr (st_ver_retr),
.end_ver_retr (end_ver_retr),
.x_dotclockdiv2 (x_dotclockdiv2),
.v_retrace (v_retrace),
.vh_retrace (vh_retrace)
);
vga_cpu_mem_iface cpu_mem_iface (
.wb_clk_i (wb_clk_i),
.wb_rst_i (wb_rst_i),
.wbs_adr_i (wb_adr_i),
.wbs_sel_i (wb_sel_i),
.wbs_we_i (wb_we_i),
.wbs_dat_i (wb_dat_i),
.wbs_dat_o (mem_wb_dat_o),
.wbs_stb_i (stb & !wb_tga_i),
.wbs_ack_o (mem_wb_ack_o),
.wbm_adr_o (wbm_adr_o),
.wbm_sel_o (wbm_sel_o),
.wbm_we_o (wbm_we_o),
.wbm_dat_o (wbm_dat_o),
.wbm_dat_i (wbm_dat_i),
.wbm_stb_o (wbm_stb_o),
.wbm_ack_i (wbm_ack_i),
.chain_four (chain_four),
.memory_mapping1 (memory_mapping1),
.write_mode (write_mode),
.raster_op (raster_op),
.read_mode (read_mode),
.bitmask (bitmask),
.set_reset (set_reset),
.enable_set_reset (enable_set_reset),
.map_mask (map_mask),
.read_map_select (read_map_select),
.color_compare (color_compare),
.color_dont_care (color_dont_care)
);
vga_mem_arbitrer mem_arbitrer (
.clk_i (wb_clk_i),
.rst_i (wb_rst_i),
.wb_adr_i (wbm_adr_o),
.wb_sel_i (wbm_sel_o),
.wb_we_i (wbm_we_o),
.wb_dat_i (wbm_dat_o),
.wb_dat_o (wbm_dat_i),
.wb_stb_i (wbm_stb_o),
.wb_ack_o (wbm_ack_i),
.csr_adr_i (csr_adr_i),
.csr_dat_o (csr_dat_i),
.csr_stb_i (csr_stb_i),
.csrm_adr_o (csrm_adr_o),
.csrm_sel_o (csrm_sel_o),
.csrm_we_o (csrm_we_o),
.csrm_dat_o (csrm_dat_o),
.csrm_dat_i (csrm_dat_i)
);
// Continous assignments
assign wb_dat_o = wb_tga_i ? conf_wb_dat_o : mem_wb_dat_o;
assign wb_ack_o = wb_tga_i ? conf_wb_ack_o : mem_wb_ack_o;
assign stb = wb_stb_i & wb_cyc_i;
assign vert_sync = ~graphics_alpha ^ w_vert_sync;
// Behaviour
// csr_adr_i
always @(posedge wb_clk_i)
csr_adr_i <= wb_rst_i ? 17'h0 : csr_adr_o + start_addr[15:1];
// csr_stb_i
always @(posedge wb_clk_i)
csr_stb_i <= wb_rst_i ? 1'b0 : csr_stb_o;
endmodule |
module vga (
// Wishbone signals
input wb_clk_i, // 25 Mhz VDU clock
input wb_rst_i,
input [15:0] wb_dat_i,
output [15:0] wb_dat_o,
input [16:1] wb_adr_i,
input wb_we_i,
input wb_tga_i,
input [ 1:0] wb_sel_i,
input wb_stb_i,
input wb_cyc_i,
output wb_ack_o,
// VGA pad signals
output [ 3:0] vga_red_o,
output [ 3:0] vga_green_o,
output [ 3:0] vga_blue_o,
output horiz_sync,
output vert_sync,
// CSR SRAM master interface
output [17:1] csrm_adr_o,
output [ 1:0] csrm_sel_o,
output csrm_we_o,
output [15:0] csrm_dat_o,
input [15:0] csrm_dat_i
);
// Registers and nets
//
// csr address
reg [17:1] csr_adr_i;
reg csr_stb_i;
// Config wires
wire [15:0] conf_wb_dat_o;
wire conf_wb_ack_o;
// Mem wires
wire [15:0] mem_wb_dat_o;
wire mem_wb_ack_o;
// LCD wires
wire [17:1] csr_adr_o;
wire [15:0] csr_dat_i;
wire csr_stb_o;
wire v_retrace;
wire vh_retrace;
wire w_vert_sync;
// VGA configuration registers
wire shift_reg1;
wire graphics_alpha;
wire memory_mapping1;
wire [ 1:0] write_mode;
wire [ 1:0] raster_op;
wire read_mode;
wire [ 7:0] bitmask;
wire [ 3:0] set_reset;
wire [ 3:0] enable_set_reset;
wire [ 3:0] map_mask;
wire x_dotclockdiv2;
wire chain_four;
wire [ 1:0] read_map_select;
wire [ 3:0] color_compare;
wire [ 3:0] color_dont_care;
// Wishbone master to SRAM
wire [17:1] wbm_adr_o;
wire [ 1:0] wbm_sel_o;
wire wbm_we_o;
wire [15:0] wbm_dat_o;
wire [15:0] wbm_dat_i;
wire wbm_stb_o;
wire wbm_ack_i;
wire stb;
// CRT wires
wire [ 5:0] cur_start;
wire [ 5:0] cur_end;
wire [15:0] start_addr;
wire [ 4:0] vcursor;
wire [ 6:0] hcursor;
wire [ 6:0] horiz_total;
wire [ 6:0] end_horiz;
wire [ 6:0] st_hor_retr;
wire [ 4:0] end_hor_retr;
wire [ 9:0] vert_total;
wire [ 9:0] end_vert;
wire [ 9:0] st_ver_retr;
wire [ 3:0] end_ver_retr;
// attribute_ctrl wires
wire [3:0] pal_addr;
wire pal_we;
wire [7:0] pal_read;
wire [7:0] pal_write;
// dac_regs wires
wire dac_we;
wire [1:0] dac_read_data_cycle;
wire [7:0] dac_read_data_register;
wire [3:0] dac_read_data;
wire [1:0] dac_write_data_cycle;
wire [7:0] dac_write_data_register;
wire [3:0] dac_write_data;
// Module instances
//
vga_config_iface config_iface (
.wb_clk_i (wb_clk_i),
.wb_rst_i (wb_rst_i),
.wb_dat_i (wb_dat_i),
.wb_dat_o (conf_wb_dat_o),
.wb_adr_i (wb_adr_i[4:1]),
.wb_we_i (wb_we_i),
.wb_sel_i (wb_sel_i),
.wb_stb_i (stb & wb_tga_i),
.wb_ack_o (conf_wb_ack_o),
.shift_reg1 (shift_reg1),
.graphics_alpha (graphics_alpha),
.memory_mapping1 (memory_mapping1),
.write_mode (write_mode),
.raster_op (raster_op),
.read_mode (read_mode),
.bitmask (bitmask),
.set_reset (set_reset),
.enable_set_reset (enable_set_reset),
.map_mask (map_mask),
.x_dotclockdiv2 (x_dotclockdiv2),
.chain_four (chain_four),
.read_map_select (read_map_select),
.color_compare (color_compare),
.color_dont_care (color_dont_care),
.pal_addr (pal_addr),
.pal_we (pal_we),
.pal_read (pal_read),
.pal_write (pal_write),
.dac_we (dac_we),
.dac_read_data_cycle (dac_read_data_cycle),
.dac_read_data_register (dac_read_data_register),
.dac_read_data (dac_read_data),
.dac_write_data_cycle (dac_write_data_cycle),
.dac_write_data_register (dac_write_data_register),
.dac_write_data (dac_write_data),
.cur_start (cur_start),
.cur_end (cur_end),
.start_addr (start_addr),
.vcursor (vcursor),
.hcursor (hcursor),
.horiz_total (horiz_total),
.end_horiz (end_horiz),
.st_hor_retr (st_hor_retr),
.end_hor_retr (end_hor_retr),
.vert_total (vert_total),
.end_vert (end_vert),
.st_ver_retr (st_ver_retr),
.end_ver_retr (end_ver_retr),
.v_retrace (v_retrace),
.vh_retrace (vh_retrace)
);
vga_lcd lcd (
.clk (wb_clk_i),
.rst (wb_rst_i),
.shift_reg1 (shift_reg1),
.graphics_alpha (graphics_alpha),
.pal_addr (pal_addr),
.pal_we (pal_we),
.pal_read (pal_read),
.pal_write (pal_write),
.dac_we (dac_we),
.dac_read_data_cycle (dac_read_data_cycle),
.dac_read_data_register (dac_read_data_register),
.dac_read_data (dac_read_data),
.dac_write_data_cycle (dac_write_data_cycle),
.dac_write_data_register (dac_write_data_register),
.dac_write_data (dac_write_data),
.csr_adr_o (csr_adr_o),
.csr_dat_i (csr_dat_i),
.csr_stb_o (csr_stb_o),
.vga_red_o (vga_red_o),
.vga_green_o (vga_green_o),
.vga_blue_o (vga_blue_o),
.horiz_sync (horiz_sync),
.vert_sync (w_vert_sync),
.cur_start (cur_start),
.cur_end (cur_end),
.vcursor (vcursor),
.hcursor (hcursor),
.horiz_total (horiz_total),
.end_horiz (end_horiz),
.st_hor_retr (st_hor_retr),
.end_hor_retr (end_hor_retr),
.vert_total (vert_total),
.end_vert (end_vert),
.st_ver_retr (st_ver_retr),
.end_ver_retr (end_ver_retr),
.x_dotclockdiv2 (x_dotclockdiv2),
.v_retrace (v_retrace),
.vh_retrace (vh_retrace)
);
vga_cpu_mem_iface cpu_mem_iface (
.wb_clk_i (wb_clk_i),
.wb_rst_i (wb_rst_i),
.wbs_adr_i (wb_adr_i),
.wbs_sel_i (wb_sel_i),
.wbs_we_i (wb_we_i),
.wbs_dat_i (wb_dat_i),
.wbs_dat_o (mem_wb_dat_o),
.wbs_stb_i (stb & !wb_tga_i),
.wbs_ack_o (mem_wb_ack_o),
.wbm_adr_o (wbm_adr_o),
.wbm_sel_o (wbm_sel_o),
.wbm_we_o (wbm_we_o),
.wbm_dat_o (wbm_dat_o),
.wbm_dat_i (wbm_dat_i),
.wbm_stb_o (wbm_stb_o),
.wbm_ack_i (wbm_ack_i),
.chain_four (chain_four),
.memory_mapping1 (memory_mapping1),
.write_mode (write_mode),
.raster_op (raster_op),
.read_mode (read_mode),
.bitmask (bitmask),
.set_reset (set_reset),
.enable_set_reset (enable_set_reset),
.map_mask (map_mask),
.read_map_select (read_map_select),
.color_compare (color_compare),
.color_dont_care (color_dont_care)
);
vga_mem_arbitrer mem_arbitrer (
.clk_i (wb_clk_i),
.rst_i (wb_rst_i),
.wb_adr_i (wbm_adr_o),
.wb_sel_i (wbm_sel_o),
.wb_we_i (wbm_we_o),
.wb_dat_i (wbm_dat_o),
.wb_dat_o (wbm_dat_i),
.wb_stb_i (wbm_stb_o),
.wb_ack_o (wbm_ack_i),
.csr_adr_i (csr_adr_i),
.csr_dat_o (csr_dat_i),
.csr_stb_i (csr_stb_i),
.csrm_adr_o (csrm_adr_o),
.csrm_sel_o (csrm_sel_o),
.csrm_we_o (csrm_we_o),
.csrm_dat_o (csrm_dat_o),
.csrm_dat_i (csrm_dat_i)
);
// Continous assignments
assign wb_dat_o = wb_tga_i ? conf_wb_dat_o : mem_wb_dat_o;
assign wb_ack_o = wb_tga_i ? conf_wb_ack_o : mem_wb_ack_o;
assign stb = wb_stb_i & wb_cyc_i;
assign vert_sync = ~graphics_alpha ^ w_vert_sync;
// Behaviour
// csr_adr_i
always @(posedge wb_clk_i)
csr_adr_i <= wb_rst_i ? 17'h0 : csr_adr_o + start_addr[15:1];
// csr_stb_i
always @(posedge wb_clk_i)
csr_stb_i <= wb_rst_i ? 1'b0 : csr_stb_o;
endmodule |
module vga (
// Wishbone signals
input wb_clk_i, // 25 Mhz VDU clock
input wb_rst_i,
input [15:0] wb_dat_i,
output [15:0] wb_dat_o,
input [16:1] wb_adr_i,
input wb_we_i,
input wb_tga_i,
input [ 1:0] wb_sel_i,
input wb_stb_i,
input wb_cyc_i,
output wb_ack_o,
// VGA pad signals
output [ 3:0] vga_red_o,
output [ 3:0] vga_green_o,
output [ 3:0] vga_blue_o,
output horiz_sync,
output vert_sync,
// CSR SRAM master interface
output [17:1] csrm_adr_o,
output [ 1:0] csrm_sel_o,
output csrm_we_o,
output [15:0] csrm_dat_o,
input [15:0] csrm_dat_i
);
// Registers and nets
//
// csr address
reg [17:1] csr_adr_i;
reg csr_stb_i;
// Config wires
wire [15:0] conf_wb_dat_o;
wire conf_wb_ack_o;
// Mem wires
wire [15:0] mem_wb_dat_o;
wire mem_wb_ack_o;
// LCD wires
wire [17:1] csr_adr_o;
wire [15:0] csr_dat_i;
wire csr_stb_o;
wire v_retrace;
wire vh_retrace;
wire w_vert_sync;
// VGA configuration registers
wire shift_reg1;
wire graphics_alpha;
wire memory_mapping1;
wire [ 1:0] write_mode;
wire [ 1:0] raster_op;
wire read_mode;
wire [ 7:0] bitmask;
wire [ 3:0] set_reset;
wire [ 3:0] enable_set_reset;
wire [ 3:0] map_mask;
wire x_dotclockdiv2;
wire chain_four;
wire [ 1:0] read_map_select;
wire [ 3:0] color_compare;
wire [ 3:0] color_dont_care;
// Wishbone master to SRAM
wire [17:1] wbm_adr_o;
wire [ 1:0] wbm_sel_o;
wire wbm_we_o;
wire [15:0] wbm_dat_o;
wire [15:0] wbm_dat_i;
wire wbm_stb_o;
wire wbm_ack_i;
wire stb;
// CRT wires
wire [ 5:0] cur_start;
wire [ 5:0] cur_end;
wire [15:0] start_addr;
wire [ 4:0] vcursor;
wire [ 6:0] hcursor;
wire [ 6:0] horiz_total;
wire [ 6:0] end_horiz;
wire [ 6:0] st_hor_retr;
wire [ 4:0] end_hor_retr;
wire [ 9:0] vert_total;
wire [ 9:0] end_vert;
wire [ 9:0] st_ver_retr;
wire [ 3:0] end_ver_retr;
// attribute_ctrl wires
wire [3:0] pal_addr;
wire pal_we;
wire [7:0] pal_read;
wire [7:0] pal_write;
// dac_regs wires
wire dac_we;
wire [1:0] dac_read_data_cycle;
wire [7:0] dac_read_data_register;
wire [3:0] dac_read_data;
wire [1:0] dac_write_data_cycle;
wire [7:0] dac_write_data_register;
wire [3:0] dac_write_data;
// Module instances
//
vga_config_iface config_iface (
.wb_clk_i (wb_clk_i),
.wb_rst_i (wb_rst_i),
.wb_dat_i (wb_dat_i),
.wb_dat_o (conf_wb_dat_o),
.wb_adr_i (wb_adr_i[4:1]),
.wb_we_i (wb_we_i),
.wb_sel_i (wb_sel_i),
.wb_stb_i (stb & wb_tga_i),
.wb_ack_o (conf_wb_ack_o),
.shift_reg1 (shift_reg1),
.graphics_alpha (graphics_alpha),
.memory_mapping1 (memory_mapping1),
.write_mode (write_mode),
.raster_op (raster_op),
.read_mode (read_mode),
.bitmask (bitmask),
.set_reset (set_reset),
.enable_set_reset (enable_set_reset),
.map_mask (map_mask),
.x_dotclockdiv2 (x_dotclockdiv2),
.chain_four (chain_four),
.read_map_select (read_map_select),
.color_compare (color_compare),
.color_dont_care (color_dont_care),
.pal_addr (pal_addr),
.pal_we (pal_we),
.pal_read (pal_read),
.pal_write (pal_write),
.dac_we (dac_we),
.dac_read_data_cycle (dac_read_data_cycle),
.dac_read_data_register (dac_read_data_register),
.dac_read_data (dac_read_data),
.dac_write_data_cycle (dac_write_data_cycle),
.dac_write_data_register (dac_write_data_register),
.dac_write_data (dac_write_data),
.cur_start (cur_start),
.cur_end (cur_end),
.start_addr (start_addr),
.vcursor (vcursor),
.hcursor (hcursor),
.horiz_total (horiz_total),
.end_horiz (end_horiz),
.st_hor_retr (st_hor_retr),
.end_hor_retr (end_hor_retr),
.vert_total (vert_total),
.end_vert (end_vert),
.st_ver_retr (st_ver_retr),
.end_ver_retr (end_ver_retr),
.v_retrace (v_retrace),
.vh_retrace (vh_retrace)
);
vga_lcd lcd (
.clk (wb_clk_i),
.rst (wb_rst_i),
.shift_reg1 (shift_reg1),
.graphics_alpha (graphics_alpha),
.pal_addr (pal_addr),
.pal_we (pal_we),
.pal_read (pal_read),
.pal_write (pal_write),
.dac_we (dac_we),
.dac_read_data_cycle (dac_read_data_cycle),
.dac_read_data_register (dac_read_data_register),
.dac_read_data (dac_read_data),
.dac_write_data_cycle (dac_write_data_cycle),
.dac_write_data_register (dac_write_data_register),
.dac_write_data (dac_write_data),
.csr_adr_o (csr_adr_o),
.csr_dat_i (csr_dat_i),
.csr_stb_o (csr_stb_o),
.vga_red_o (vga_red_o),
.vga_green_o (vga_green_o),
.vga_blue_o (vga_blue_o),
.horiz_sync (horiz_sync),
.vert_sync (w_vert_sync),
.cur_start (cur_start),
.cur_end (cur_end),
.vcursor (vcursor),
.hcursor (hcursor),
.horiz_total (horiz_total),
.end_horiz (end_horiz),
.st_hor_retr (st_hor_retr),
.end_hor_retr (end_hor_retr),
.vert_total (vert_total),
.end_vert (end_vert),
.st_ver_retr (st_ver_retr),
.end_ver_retr (end_ver_retr),
.x_dotclockdiv2 (x_dotclockdiv2),
.v_retrace (v_retrace),
.vh_retrace (vh_retrace)
);
vga_cpu_mem_iface cpu_mem_iface (
.wb_clk_i (wb_clk_i),
.wb_rst_i (wb_rst_i),
.wbs_adr_i (wb_adr_i),
.wbs_sel_i (wb_sel_i),
.wbs_we_i (wb_we_i),
.wbs_dat_i (wb_dat_i),
.wbs_dat_o (mem_wb_dat_o),
.wbs_stb_i (stb & !wb_tga_i),
.wbs_ack_o (mem_wb_ack_o),
.wbm_adr_o (wbm_adr_o),
.wbm_sel_o (wbm_sel_o),
.wbm_we_o (wbm_we_o),
.wbm_dat_o (wbm_dat_o),
.wbm_dat_i (wbm_dat_i),
.wbm_stb_o (wbm_stb_o),
.wbm_ack_i (wbm_ack_i),
.chain_four (chain_four),
.memory_mapping1 (memory_mapping1),
.write_mode (write_mode),
.raster_op (raster_op),
.read_mode (read_mode),
.bitmask (bitmask),
.set_reset (set_reset),
.enable_set_reset (enable_set_reset),
.map_mask (map_mask),
.read_map_select (read_map_select),
.color_compare (color_compare),
.color_dont_care (color_dont_care)
);
vga_mem_arbitrer mem_arbitrer (
.clk_i (wb_clk_i),
.rst_i (wb_rst_i),
.wb_adr_i (wbm_adr_o),
.wb_sel_i (wbm_sel_o),
.wb_we_i (wbm_we_o),
.wb_dat_i (wbm_dat_o),
.wb_dat_o (wbm_dat_i),
.wb_stb_i (wbm_stb_o),
.wb_ack_o (wbm_ack_i),
.csr_adr_i (csr_adr_i),
.csr_dat_o (csr_dat_i),
.csr_stb_i (csr_stb_i),
.csrm_adr_o (csrm_adr_o),
.csrm_sel_o (csrm_sel_o),
.csrm_we_o (csrm_we_o),
.csrm_dat_o (csrm_dat_o),
.csrm_dat_i (csrm_dat_i)
);
// Continous assignments
assign wb_dat_o = wb_tga_i ? conf_wb_dat_o : mem_wb_dat_o;
assign wb_ack_o = wb_tga_i ? conf_wb_ack_o : mem_wb_ack_o;
assign stb = wb_stb_i & wb_cyc_i;
assign vert_sync = ~graphics_alpha ^ w_vert_sync;
// Behaviour
// csr_adr_i
always @(posedge wb_clk_i)
csr_adr_i <= wb_rst_i ? 17'h0 : csr_adr_o + start_addr[15:1];
// csr_stb_i
always @(posedge wb_clk_i)
csr_stb_i <= wb_rst_i ? 1'b0 : csr_stb_o;
endmodule |
module vga (
// Wishbone signals
input wb_clk_i, // 25 Mhz VDU clock
input wb_rst_i,
input [15:0] wb_dat_i,
output [15:0] wb_dat_o,
input [16:1] wb_adr_i,
input wb_we_i,
input wb_tga_i,
input [ 1:0] wb_sel_i,
input wb_stb_i,
input wb_cyc_i,
output wb_ack_o,
// VGA pad signals
output [ 3:0] vga_red_o,
output [ 3:0] vga_green_o,
output [ 3:0] vga_blue_o,
output horiz_sync,
output vert_sync,
// CSR SRAM master interface
output [17:1] csrm_adr_o,
output [ 1:0] csrm_sel_o,
output csrm_we_o,
output [15:0] csrm_dat_o,
input [15:0] csrm_dat_i
);
// Registers and nets
//
// csr address
reg [17:1] csr_adr_i;
reg csr_stb_i;
// Config wires
wire [15:0] conf_wb_dat_o;
wire conf_wb_ack_o;
// Mem wires
wire [15:0] mem_wb_dat_o;
wire mem_wb_ack_o;
// LCD wires
wire [17:1] csr_adr_o;
wire [15:0] csr_dat_i;
wire csr_stb_o;
wire v_retrace;
wire vh_retrace;
wire w_vert_sync;
// VGA configuration registers
wire shift_reg1;
wire graphics_alpha;
wire memory_mapping1;
wire [ 1:0] write_mode;
wire [ 1:0] raster_op;
wire read_mode;
wire [ 7:0] bitmask;
wire [ 3:0] set_reset;
wire [ 3:0] enable_set_reset;
wire [ 3:0] map_mask;
wire x_dotclockdiv2;
wire chain_four;
wire [ 1:0] read_map_select;
wire [ 3:0] color_compare;
wire [ 3:0] color_dont_care;
// Wishbone master to SRAM
wire [17:1] wbm_adr_o;
wire [ 1:0] wbm_sel_o;
wire wbm_we_o;
wire [15:0] wbm_dat_o;
wire [15:0] wbm_dat_i;
wire wbm_stb_o;
wire wbm_ack_i;
wire stb;
// CRT wires
wire [ 5:0] cur_start;
wire [ 5:0] cur_end;
wire [15:0] start_addr;
wire [ 4:0] vcursor;
wire [ 6:0] hcursor;
wire [ 6:0] horiz_total;
wire [ 6:0] end_horiz;
wire [ 6:0] st_hor_retr;
wire [ 4:0] end_hor_retr;
wire [ 9:0] vert_total;
wire [ 9:0] end_vert;
wire [ 9:0] st_ver_retr;
wire [ 3:0] end_ver_retr;
// attribute_ctrl wires
wire [3:0] pal_addr;
wire pal_we;
wire [7:0] pal_read;
wire [7:0] pal_write;
// dac_regs wires
wire dac_we;
wire [1:0] dac_read_data_cycle;
wire [7:0] dac_read_data_register;
wire [3:0] dac_read_data;
wire [1:0] dac_write_data_cycle;
wire [7:0] dac_write_data_register;
wire [3:0] dac_write_data;
// Module instances
//
vga_config_iface config_iface (
.wb_clk_i (wb_clk_i),
.wb_rst_i (wb_rst_i),
.wb_dat_i (wb_dat_i),
.wb_dat_o (conf_wb_dat_o),
.wb_adr_i (wb_adr_i[4:1]),
.wb_we_i (wb_we_i),
.wb_sel_i (wb_sel_i),
.wb_stb_i (stb & wb_tga_i),
.wb_ack_o (conf_wb_ack_o),
.shift_reg1 (shift_reg1),
.graphics_alpha (graphics_alpha),
.memory_mapping1 (memory_mapping1),
.write_mode (write_mode),
.raster_op (raster_op),
.read_mode (read_mode),
.bitmask (bitmask),
.set_reset (set_reset),
.enable_set_reset (enable_set_reset),
.map_mask (map_mask),
.x_dotclockdiv2 (x_dotclockdiv2),
.chain_four (chain_four),
.read_map_select (read_map_select),
.color_compare (color_compare),
.color_dont_care (color_dont_care),
.pal_addr (pal_addr),
.pal_we (pal_we),
.pal_read (pal_read),
.pal_write (pal_write),
.dac_we (dac_we),
.dac_read_data_cycle (dac_read_data_cycle),
.dac_read_data_register (dac_read_data_register),
.dac_read_data (dac_read_data),
.dac_write_data_cycle (dac_write_data_cycle),
.dac_write_data_register (dac_write_data_register),
.dac_write_data (dac_write_data),
.cur_start (cur_start),
.cur_end (cur_end),
.start_addr (start_addr),
.vcursor (vcursor),
.hcursor (hcursor),
.horiz_total (horiz_total),
.end_horiz (end_horiz),
.st_hor_retr (st_hor_retr),
.end_hor_retr (end_hor_retr),
.vert_total (vert_total),
.end_vert (end_vert),
.st_ver_retr (st_ver_retr),
.end_ver_retr (end_ver_retr),
.v_retrace (v_retrace),
.vh_retrace (vh_retrace)
);
vga_lcd lcd (
.clk (wb_clk_i),
.rst (wb_rst_i),
.shift_reg1 (shift_reg1),
.graphics_alpha (graphics_alpha),
.pal_addr (pal_addr),
.pal_we (pal_we),
.pal_read (pal_read),
.pal_write (pal_write),
.dac_we (dac_we),
.dac_read_data_cycle (dac_read_data_cycle),
.dac_read_data_register (dac_read_data_register),
.dac_read_data (dac_read_data),
.dac_write_data_cycle (dac_write_data_cycle),
.dac_write_data_register (dac_write_data_register),
.dac_write_data (dac_write_data),
.csr_adr_o (csr_adr_o),
.csr_dat_i (csr_dat_i),
.csr_stb_o (csr_stb_o),
.vga_red_o (vga_red_o),
.vga_green_o (vga_green_o),
.vga_blue_o (vga_blue_o),
.horiz_sync (horiz_sync),
.vert_sync (w_vert_sync),
.cur_start (cur_start),
.cur_end (cur_end),
.vcursor (vcursor),
.hcursor (hcursor),
.horiz_total (horiz_total),
.end_horiz (end_horiz),
.st_hor_retr (st_hor_retr),
.end_hor_retr (end_hor_retr),
.vert_total (vert_total),
.end_vert (end_vert),
.st_ver_retr (st_ver_retr),
.end_ver_retr (end_ver_retr),
.x_dotclockdiv2 (x_dotclockdiv2),
.v_retrace (v_retrace),
.vh_retrace (vh_retrace)
);
vga_cpu_mem_iface cpu_mem_iface (
.wb_clk_i (wb_clk_i),
.wb_rst_i (wb_rst_i),
.wbs_adr_i (wb_adr_i),
.wbs_sel_i (wb_sel_i),
.wbs_we_i (wb_we_i),
.wbs_dat_i (wb_dat_i),
.wbs_dat_o (mem_wb_dat_o),
.wbs_stb_i (stb & !wb_tga_i),
.wbs_ack_o (mem_wb_ack_o),
.wbm_adr_o (wbm_adr_o),
.wbm_sel_o (wbm_sel_o),
.wbm_we_o (wbm_we_o),
.wbm_dat_o (wbm_dat_o),
.wbm_dat_i (wbm_dat_i),
.wbm_stb_o (wbm_stb_o),
.wbm_ack_i (wbm_ack_i),
.chain_four (chain_four),
.memory_mapping1 (memory_mapping1),
.write_mode (write_mode),
.raster_op (raster_op),
.read_mode (read_mode),
.bitmask (bitmask),
.set_reset (set_reset),
.enable_set_reset (enable_set_reset),
.map_mask (map_mask),
.read_map_select (read_map_select),
.color_compare (color_compare),
.color_dont_care (color_dont_care)
);
vga_mem_arbitrer mem_arbitrer (
.clk_i (wb_clk_i),
.rst_i (wb_rst_i),
.wb_adr_i (wbm_adr_o),
.wb_sel_i (wbm_sel_o),
.wb_we_i (wbm_we_o),
.wb_dat_i (wbm_dat_o),
.wb_dat_o (wbm_dat_i),
.wb_stb_i (wbm_stb_o),
.wb_ack_o (wbm_ack_i),
.csr_adr_i (csr_adr_i),
.csr_dat_o (csr_dat_i),
.csr_stb_i (csr_stb_i),
.csrm_adr_o (csrm_adr_o),
.csrm_sel_o (csrm_sel_o),
.csrm_we_o (csrm_we_o),
.csrm_dat_o (csrm_dat_o),
.csrm_dat_i (csrm_dat_i)
);
// Continous assignments
assign wb_dat_o = wb_tga_i ? conf_wb_dat_o : mem_wb_dat_o;
assign wb_ack_o = wb_tga_i ? conf_wb_ack_o : mem_wb_ack_o;
assign stb = wb_stb_i & wb_cyc_i;
assign vert_sync = ~graphics_alpha ^ w_vert_sync;
// Behaviour
// csr_adr_i
always @(posedge wb_clk_i)
csr_adr_i <= wb_rst_i ? 17'h0 : csr_adr_o + start_addr[15:1];
// csr_stb_i
always @(posedge wb_clk_i)
csr_stb_i <= wb_rst_i ? 1'b0 : csr_stb_o;
endmodule |
module vga (
// Wishbone signals
input wb_clk_i, // 25 Mhz VDU clock
input wb_rst_i,
input [15:0] wb_dat_i,
output [15:0] wb_dat_o,
input [16:1] wb_adr_i,
input wb_we_i,
input wb_tga_i,
input [ 1:0] wb_sel_i,
input wb_stb_i,
input wb_cyc_i,
output wb_ack_o,
// VGA pad signals
output [ 3:0] vga_red_o,
output [ 3:0] vga_green_o,
output [ 3:0] vga_blue_o,
output horiz_sync,
output vert_sync,
// CSR SRAM master interface
output [17:1] csrm_adr_o,
output [ 1:0] csrm_sel_o,
output csrm_we_o,
output [15:0] csrm_dat_o,
input [15:0] csrm_dat_i
);
// Registers and nets
//
// csr address
reg [17:1] csr_adr_i;
reg csr_stb_i;
// Config wires
wire [15:0] conf_wb_dat_o;
wire conf_wb_ack_o;
// Mem wires
wire [15:0] mem_wb_dat_o;
wire mem_wb_ack_o;
// LCD wires
wire [17:1] csr_adr_o;
wire [15:0] csr_dat_i;
wire csr_stb_o;
wire v_retrace;
wire vh_retrace;
wire w_vert_sync;
// VGA configuration registers
wire shift_reg1;
wire graphics_alpha;
wire memory_mapping1;
wire [ 1:0] write_mode;
wire [ 1:0] raster_op;
wire read_mode;
wire [ 7:0] bitmask;
wire [ 3:0] set_reset;
wire [ 3:0] enable_set_reset;
wire [ 3:0] map_mask;
wire x_dotclockdiv2;
wire chain_four;
wire [ 1:0] read_map_select;
wire [ 3:0] color_compare;
wire [ 3:0] color_dont_care;
// Wishbone master to SRAM
wire [17:1] wbm_adr_o;
wire [ 1:0] wbm_sel_o;
wire wbm_we_o;
wire [15:0] wbm_dat_o;
wire [15:0] wbm_dat_i;
wire wbm_stb_o;
wire wbm_ack_i;
wire stb;
// CRT wires
wire [ 5:0] cur_start;
wire [ 5:0] cur_end;
wire [15:0] start_addr;
wire [ 4:0] vcursor;
wire [ 6:0] hcursor;
wire [ 6:0] horiz_total;
wire [ 6:0] end_horiz;
wire [ 6:0] st_hor_retr;
wire [ 4:0] end_hor_retr;
wire [ 9:0] vert_total;
wire [ 9:0] end_vert;
wire [ 9:0] st_ver_retr;
wire [ 3:0] end_ver_retr;
// attribute_ctrl wires
wire [3:0] pal_addr;
wire pal_we;
wire [7:0] pal_read;
wire [7:0] pal_write;
// dac_regs wires
wire dac_we;
wire [1:0] dac_read_data_cycle;
wire [7:0] dac_read_data_register;
wire [3:0] dac_read_data;
wire [1:0] dac_write_data_cycle;
wire [7:0] dac_write_data_register;
wire [3:0] dac_write_data;
// Module instances
//
vga_config_iface config_iface (
.wb_clk_i (wb_clk_i),
.wb_rst_i (wb_rst_i),
.wb_dat_i (wb_dat_i),
.wb_dat_o (conf_wb_dat_o),
.wb_adr_i (wb_adr_i[4:1]),
.wb_we_i (wb_we_i),
.wb_sel_i (wb_sel_i),
.wb_stb_i (stb & wb_tga_i),
.wb_ack_o (conf_wb_ack_o),
.shift_reg1 (shift_reg1),
.graphics_alpha (graphics_alpha),
.memory_mapping1 (memory_mapping1),
.write_mode (write_mode),
.raster_op (raster_op),
.read_mode (read_mode),
.bitmask (bitmask),
.set_reset (set_reset),
.enable_set_reset (enable_set_reset),
.map_mask (map_mask),
.x_dotclockdiv2 (x_dotclockdiv2),
.chain_four (chain_four),
.read_map_select (read_map_select),
.color_compare (color_compare),
.color_dont_care (color_dont_care),
.pal_addr (pal_addr),
.pal_we (pal_we),
.pal_read (pal_read),
.pal_write (pal_write),
.dac_we (dac_we),
.dac_read_data_cycle (dac_read_data_cycle),
.dac_read_data_register (dac_read_data_register),
.dac_read_data (dac_read_data),
.dac_write_data_cycle (dac_write_data_cycle),
.dac_write_data_register (dac_write_data_register),
.dac_write_data (dac_write_data),
.cur_start (cur_start),
.cur_end (cur_end),
.start_addr (start_addr),
.vcursor (vcursor),
.hcursor (hcursor),
.horiz_total (horiz_total),
.end_horiz (end_horiz),
.st_hor_retr (st_hor_retr),
.end_hor_retr (end_hor_retr),
.vert_total (vert_total),
.end_vert (end_vert),
.st_ver_retr (st_ver_retr),
.end_ver_retr (end_ver_retr),
.v_retrace (v_retrace),
.vh_retrace (vh_retrace)
);
vga_lcd lcd (
.clk (wb_clk_i),
.rst (wb_rst_i),
.shift_reg1 (shift_reg1),
.graphics_alpha (graphics_alpha),
.pal_addr (pal_addr),
.pal_we (pal_we),
.pal_read (pal_read),
.pal_write (pal_write),
.dac_we (dac_we),
.dac_read_data_cycle (dac_read_data_cycle),
.dac_read_data_register (dac_read_data_register),
.dac_read_data (dac_read_data),
.dac_write_data_cycle (dac_write_data_cycle),
.dac_write_data_register (dac_write_data_register),
.dac_write_data (dac_write_data),
.csr_adr_o (csr_adr_o),
.csr_dat_i (csr_dat_i),
.csr_stb_o (csr_stb_o),
.vga_red_o (vga_red_o),
.vga_green_o (vga_green_o),
.vga_blue_o (vga_blue_o),
.horiz_sync (horiz_sync),
.vert_sync (w_vert_sync),
.cur_start (cur_start),
.cur_end (cur_end),
.vcursor (vcursor),
.hcursor (hcursor),
.horiz_total (horiz_total),
.end_horiz (end_horiz),
.st_hor_retr (st_hor_retr),
.end_hor_retr (end_hor_retr),
.vert_total (vert_total),
.end_vert (end_vert),
.st_ver_retr (st_ver_retr),
.end_ver_retr (end_ver_retr),
.x_dotclockdiv2 (x_dotclockdiv2),
.v_retrace (v_retrace),
.vh_retrace (vh_retrace)
);
vga_cpu_mem_iface cpu_mem_iface (
.wb_clk_i (wb_clk_i),
.wb_rst_i (wb_rst_i),
.wbs_adr_i (wb_adr_i),
.wbs_sel_i (wb_sel_i),
.wbs_we_i (wb_we_i),
.wbs_dat_i (wb_dat_i),
.wbs_dat_o (mem_wb_dat_o),
.wbs_stb_i (stb & !wb_tga_i),
.wbs_ack_o (mem_wb_ack_o),
.wbm_adr_o (wbm_adr_o),
.wbm_sel_o (wbm_sel_o),
.wbm_we_o (wbm_we_o),
.wbm_dat_o (wbm_dat_o),
.wbm_dat_i (wbm_dat_i),
.wbm_stb_o (wbm_stb_o),
.wbm_ack_i (wbm_ack_i),
.chain_four (chain_four),
.memory_mapping1 (memory_mapping1),
.write_mode (write_mode),
.raster_op (raster_op),
.read_mode (read_mode),
.bitmask (bitmask),
.set_reset (set_reset),
.enable_set_reset (enable_set_reset),
.map_mask (map_mask),
.read_map_select (read_map_select),
.color_compare (color_compare),
.color_dont_care (color_dont_care)
);
vga_mem_arbitrer mem_arbitrer (
.clk_i (wb_clk_i),
.rst_i (wb_rst_i),
.wb_adr_i (wbm_adr_o),
.wb_sel_i (wbm_sel_o),
.wb_we_i (wbm_we_o),
.wb_dat_i (wbm_dat_o),
.wb_dat_o (wbm_dat_i),
.wb_stb_i (wbm_stb_o),
.wb_ack_o (wbm_ack_i),
.csr_adr_i (csr_adr_i),
.csr_dat_o (csr_dat_i),
.csr_stb_i (csr_stb_i),
.csrm_adr_o (csrm_adr_o),
.csrm_sel_o (csrm_sel_o),
.csrm_we_o (csrm_we_o),
.csrm_dat_o (csrm_dat_o),
.csrm_dat_i (csrm_dat_i)
);
// Continous assignments
assign wb_dat_o = wb_tga_i ? conf_wb_dat_o : mem_wb_dat_o;
assign wb_ack_o = wb_tga_i ? conf_wb_ack_o : mem_wb_ack_o;
assign stb = wb_stb_i & wb_cyc_i;
assign vert_sync = ~graphics_alpha ^ w_vert_sync;
// Behaviour
// csr_adr_i
always @(posedge wb_clk_i)
csr_adr_i <= wb_rst_i ? 17'h0 : csr_adr_o + start_addr[15:1];
// csr_stb_i
always @(posedge wb_clk_i)
csr_stb_i <= wb_rst_i ? 1'b0 : csr_stb_o;
endmodule |
module vga (
// Wishbone signals
input wb_clk_i, // 25 Mhz VDU clock
input wb_rst_i,
input [15:0] wb_dat_i,
output [15:0] wb_dat_o,
input [16:1] wb_adr_i,
input wb_we_i,
input wb_tga_i,
input [ 1:0] wb_sel_i,
input wb_stb_i,
input wb_cyc_i,
output wb_ack_o,
// VGA pad signals
output [ 3:0] vga_red_o,
output [ 3:0] vga_green_o,
output [ 3:0] vga_blue_o,
output horiz_sync,
output vert_sync,
// CSR SRAM master interface
output [17:1] csrm_adr_o,
output [ 1:0] csrm_sel_o,
output csrm_we_o,
output [15:0] csrm_dat_o,
input [15:0] csrm_dat_i
);
// Registers and nets
//
// csr address
reg [17:1] csr_adr_i;
reg csr_stb_i;
// Config wires
wire [15:0] conf_wb_dat_o;
wire conf_wb_ack_o;
// Mem wires
wire [15:0] mem_wb_dat_o;
wire mem_wb_ack_o;
// LCD wires
wire [17:1] csr_adr_o;
wire [15:0] csr_dat_i;
wire csr_stb_o;
wire v_retrace;
wire vh_retrace;
wire w_vert_sync;
// VGA configuration registers
wire shift_reg1;
wire graphics_alpha;
wire memory_mapping1;
wire [ 1:0] write_mode;
wire [ 1:0] raster_op;
wire read_mode;
wire [ 7:0] bitmask;
wire [ 3:0] set_reset;
wire [ 3:0] enable_set_reset;
wire [ 3:0] map_mask;
wire x_dotclockdiv2;
wire chain_four;
wire [ 1:0] read_map_select;
wire [ 3:0] color_compare;
wire [ 3:0] color_dont_care;
// Wishbone master to SRAM
wire [17:1] wbm_adr_o;
wire [ 1:0] wbm_sel_o;
wire wbm_we_o;
wire [15:0] wbm_dat_o;
wire [15:0] wbm_dat_i;
wire wbm_stb_o;
wire wbm_ack_i;
wire stb;
// CRT wires
wire [ 5:0] cur_start;
wire [ 5:0] cur_end;
wire [15:0] start_addr;
wire [ 4:0] vcursor;
wire [ 6:0] hcursor;
wire [ 6:0] horiz_total;
wire [ 6:0] end_horiz;
wire [ 6:0] st_hor_retr;
wire [ 4:0] end_hor_retr;
wire [ 9:0] vert_total;
wire [ 9:0] end_vert;
wire [ 9:0] st_ver_retr;
wire [ 3:0] end_ver_retr;
// attribute_ctrl wires
wire [3:0] pal_addr;
wire pal_we;
wire [7:0] pal_read;
wire [7:0] pal_write;
// dac_regs wires
wire dac_we;
wire [1:0] dac_read_data_cycle;
wire [7:0] dac_read_data_register;
wire [3:0] dac_read_data;
wire [1:0] dac_write_data_cycle;
wire [7:0] dac_write_data_register;
wire [3:0] dac_write_data;
// Module instances
//
vga_config_iface config_iface (
.wb_clk_i (wb_clk_i),
.wb_rst_i (wb_rst_i),
.wb_dat_i (wb_dat_i),
.wb_dat_o (conf_wb_dat_o),
.wb_adr_i (wb_adr_i[4:1]),
.wb_we_i (wb_we_i),
.wb_sel_i (wb_sel_i),
.wb_stb_i (stb & wb_tga_i),
.wb_ack_o (conf_wb_ack_o),
.shift_reg1 (shift_reg1),
.graphics_alpha (graphics_alpha),
.memory_mapping1 (memory_mapping1),
.write_mode (write_mode),
.raster_op (raster_op),
.read_mode (read_mode),
.bitmask (bitmask),
.set_reset (set_reset),
.enable_set_reset (enable_set_reset),
.map_mask (map_mask),
.x_dotclockdiv2 (x_dotclockdiv2),
.chain_four (chain_four),
.read_map_select (read_map_select),
.color_compare (color_compare),
.color_dont_care (color_dont_care),
.pal_addr (pal_addr),
.pal_we (pal_we),
.pal_read (pal_read),
.pal_write (pal_write),
.dac_we (dac_we),
.dac_read_data_cycle (dac_read_data_cycle),
.dac_read_data_register (dac_read_data_register),
.dac_read_data (dac_read_data),
.dac_write_data_cycle (dac_write_data_cycle),
.dac_write_data_register (dac_write_data_register),
.dac_write_data (dac_write_data),
.cur_start (cur_start),
.cur_end (cur_end),
.start_addr (start_addr),
.vcursor (vcursor),
.hcursor (hcursor),
.horiz_total (horiz_total),
.end_horiz (end_horiz),
.st_hor_retr (st_hor_retr),
.end_hor_retr (end_hor_retr),
.vert_total (vert_total),
.end_vert (end_vert),
.st_ver_retr (st_ver_retr),
.end_ver_retr (end_ver_retr),
.v_retrace (v_retrace),
.vh_retrace (vh_retrace)
);
vga_lcd lcd (
.clk (wb_clk_i),
.rst (wb_rst_i),
.shift_reg1 (shift_reg1),
.graphics_alpha (graphics_alpha),
.pal_addr (pal_addr),
.pal_we (pal_we),
.pal_read (pal_read),
.pal_write (pal_write),
.dac_we (dac_we),
.dac_read_data_cycle (dac_read_data_cycle),
.dac_read_data_register (dac_read_data_register),
.dac_read_data (dac_read_data),
.dac_write_data_cycle (dac_write_data_cycle),
.dac_write_data_register (dac_write_data_register),
.dac_write_data (dac_write_data),
.csr_adr_o (csr_adr_o),
.csr_dat_i (csr_dat_i),
.csr_stb_o (csr_stb_o),
.vga_red_o (vga_red_o),
.vga_green_o (vga_green_o),
.vga_blue_o (vga_blue_o),
.horiz_sync (horiz_sync),
.vert_sync (w_vert_sync),
.cur_start (cur_start),
.cur_end (cur_end),
.vcursor (vcursor),
.hcursor (hcursor),
.horiz_total (horiz_total),
.end_horiz (end_horiz),
.st_hor_retr (st_hor_retr),
.end_hor_retr (end_hor_retr),
.vert_total (vert_total),
.end_vert (end_vert),
.st_ver_retr (st_ver_retr),
.end_ver_retr (end_ver_retr),
.x_dotclockdiv2 (x_dotclockdiv2),
.v_retrace (v_retrace),
.vh_retrace (vh_retrace)
);
vga_cpu_mem_iface cpu_mem_iface (
.wb_clk_i (wb_clk_i),
.wb_rst_i (wb_rst_i),
.wbs_adr_i (wb_adr_i),
.wbs_sel_i (wb_sel_i),
.wbs_we_i (wb_we_i),
.wbs_dat_i (wb_dat_i),
.wbs_dat_o (mem_wb_dat_o),
.wbs_stb_i (stb & !wb_tga_i),
.wbs_ack_o (mem_wb_ack_o),
.wbm_adr_o (wbm_adr_o),
.wbm_sel_o (wbm_sel_o),
.wbm_we_o (wbm_we_o),
.wbm_dat_o (wbm_dat_o),
.wbm_dat_i (wbm_dat_i),
.wbm_stb_o (wbm_stb_o),
.wbm_ack_i (wbm_ack_i),
.chain_four (chain_four),
.memory_mapping1 (memory_mapping1),
.write_mode (write_mode),
.raster_op (raster_op),
.read_mode (read_mode),
.bitmask (bitmask),
.set_reset (set_reset),
.enable_set_reset (enable_set_reset),
.map_mask (map_mask),
.read_map_select (read_map_select),
.color_compare (color_compare),
.color_dont_care (color_dont_care)
);
vga_mem_arbitrer mem_arbitrer (
.clk_i (wb_clk_i),
.rst_i (wb_rst_i),
.wb_adr_i (wbm_adr_o),
.wb_sel_i (wbm_sel_o),
.wb_we_i (wbm_we_o),
.wb_dat_i (wbm_dat_o),
.wb_dat_o (wbm_dat_i),
.wb_stb_i (wbm_stb_o),
.wb_ack_o (wbm_ack_i),
.csr_adr_i (csr_adr_i),
.csr_dat_o (csr_dat_i),
.csr_stb_i (csr_stb_i),
.csrm_adr_o (csrm_adr_o),
.csrm_sel_o (csrm_sel_o),
.csrm_we_o (csrm_we_o),
.csrm_dat_o (csrm_dat_o),
.csrm_dat_i (csrm_dat_i)
);
// Continous assignments
assign wb_dat_o = wb_tga_i ? conf_wb_dat_o : mem_wb_dat_o;
assign wb_ack_o = wb_tga_i ? conf_wb_ack_o : mem_wb_ack_o;
assign stb = wb_stb_i & wb_cyc_i;
assign vert_sync = ~graphics_alpha ^ w_vert_sync;
// Behaviour
// csr_adr_i
always @(posedge wb_clk_i)
csr_adr_i <= wb_rst_i ? 17'h0 : csr_adr_o + start_addr[15:1];
// csr_stb_i
always @(posedge wb_clk_i)
csr_stb_i <= wb_rst_i ? 1'b0 : csr_stb_o;
endmodule |
module vga (
// Wishbone signals
input wb_clk_i, // 25 Mhz VDU clock
input wb_rst_i,
input [15:0] wb_dat_i,
output [15:0] wb_dat_o,
input [16:1] wb_adr_i,
input wb_we_i,
input wb_tga_i,
input [ 1:0] wb_sel_i,
input wb_stb_i,
input wb_cyc_i,
output wb_ack_o,
// VGA pad signals
output [ 3:0] vga_red_o,
output [ 3:0] vga_green_o,
output [ 3:0] vga_blue_o,
output horiz_sync,
output vert_sync,
// CSR SRAM master interface
output [17:1] csrm_adr_o,
output [ 1:0] csrm_sel_o,
output csrm_we_o,
output [15:0] csrm_dat_o,
input [15:0] csrm_dat_i
);
// Registers and nets
//
// csr address
reg [17:1] csr_adr_i;
reg csr_stb_i;
// Config wires
wire [15:0] conf_wb_dat_o;
wire conf_wb_ack_o;
// Mem wires
wire [15:0] mem_wb_dat_o;
wire mem_wb_ack_o;
// LCD wires
wire [17:1] csr_adr_o;
wire [15:0] csr_dat_i;
wire csr_stb_o;
wire v_retrace;
wire vh_retrace;
wire w_vert_sync;
// VGA configuration registers
wire shift_reg1;
wire graphics_alpha;
wire memory_mapping1;
wire [ 1:0] write_mode;
wire [ 1:0] raster_op;
wire read_mode;
wire [ 7:0] bitmask;
wire [ 3:0] set_reset;
wire [ 3:0] enable_set_reset;
wire [ 3:0] map_mask;
wire x_dotclockdiv2;
wire chain_four;
wire [ 1:0] read_map_select;
wire [ 3:0] color_compare;
wire [ 3:0] color_dont_care;
// Wishbone master to SRAM
wire [17:1] wbm_adr_o;
wire [ 1:0] wbm_sel_o;
wire wbm_we_o;
wire [15:0] wbm_dat_o;
wire [15:0] wbm_dat_i;
wire wbm_stb_o;
wire wbm_ack_i;
wire stb;
// CRT wires
wire [ 5:0] cur_start;
wire [ 5:0] cur_end;
wire [15:0] start_addr;
wire [ 4:0] vcursor;
wire [ 6:0] hcursor;
wire [ 6:0] horiz_total;
wire [ 6:0] end_horiz;
wire [ 6:0] st_hor_retr;
wire [ 4:0] end_hor_retr;
wire [ 9:0] vert_total;
wire [ 9:0] end_vert;
wire [ 9:0] st_ver_retr;
wire [ 3:0] end_ver_retr;
// attribute_ctrl wires
wire [3:0] pal_addr;
wire pal_we;
wire [7:0] pal_read;
wire [7:0] pal_write;
// dac_regs wires
wire dac_we;
wire [1:0] dac_read_data_cycle;
wire [7:0] dac_read_data_register;
wire [3:0] dac_read_data;
wire [1:0] dac_write_data_cycle;
wire [7:0] dac_write_data_register;
wire [3:0] dac_write_data;
// Module instances
//
vga_config_iface config_iface (
.wb_clk_i (wb_clk_i),
.wb_rst_i (wb_rst_i),
.wb_dat_i (wb_dat_i),
.wb_dat_o (conf_wb_dat_o),
.wb_adr_i (wb_adr_i[4:1]),
.wb_we_i (wb_we_i),
.wb_sel_i (wb_sel_i),
.wb_stb_i (stb & wb_tga_i),
.wb_ack_o (conf_wb_ack_o),
.shift_reg1 (shift_reg1),
.graphics_alpha (graphics_alpha),
.memory_mapping1 (memory_mapping1),
.write_mode (write_mode),
.raster_op (raster_op),
.read_mode (read_mode),
.bitmask (bitmask),
.set_reset (set_reset),
.enable_set_reset (enable_set_reset),
.map_mask (map_mask),
.x_dotclockdiv2 (x_dotclockdiv2),
.chain_four (chain_four),
.read_map_select (read_map_select),
.color_compare (color_compare),
.color_dont_care (color_dont_care),
.pal_addr (pal_addr),
.pal_we (pal_we),
.pal_read (pal_read),
.pal_write (pal_write),
.dac_we (dac_we),
.dac_read_data_cycle (dac_read_data_cycle),
.dac_read_data_register (dac_read_data_register),
.dac_read_data (dac_read_data),
.dac_write_data_cycle (dac_write_data_cycle),
.dac_write_data_register (dac_write_data_register),
.dac_write_data (dac_write_data),
.cur_start (cur_start),
.cur_end (cur_end),
.start_addr (start_addr),
.vcursor (vcursor),
.hcursor (hcursor),
.horiz_total (horiz_total),
.end_horiz (end_horiz),
.st_hor_retr (st_hor_retr),
.end_hor_retr (end_hor_retr),
.vert_total (vert_total),
.end_vert (end_vert),
.st_ver_retr (st_ver_retr),
.end_ver_retr (end_ver_retr),
.v_retrace (v_retrace),
.vh_retrace (vh_retrace)
);
vga_lcd lcd (
.clk (wb_clk_i),
.rst (wb_rst_i),
.shift_reg1 (shift_reg1),
.graphics_alpha (graphics_alpha),
.pal_addr (pal_addr),
.pal_we (pal_we),
.pal_read (pal_read),
.pal_write (pal_write),
.dac_we (dac_we),
.dac_read_data_cycle (dac_read_data_cycle),
.dac_read_data_register (dac_read_data_register),
.dac_read_data (dac_read_data),
.dac_write_data_cycle (dac_write_data_cycle),
.dac_write_data_register (dac_write_data_register),
.dac_write_data (dac_write_data),
.csr_adr_o (csr_adr_o),
.csr_dat_i (csr_dat_i),
.csr_stb_o (csr_stb_o),
.vga_red_o (vga_red_o),
.vga_green_o (vga_green_o),
.vga_blue_o (vga_blue_o),
.horiz_sync (horiz_sync),
.vert_sync (w_vert_sync),
.cur_start (cur_start),
.cur_end (cur_end),
.vcursor (vcursor),
.hcursor (hcursor),
.horiz_total (horiz_total),
.end_horiz (end_horiz),
.st_hor_retr (st_hor_retr),
.end_hor_retr (end_hor_retr),
.vert_total (vert_total),
.end_vert (end_vert),
.st_ver_retr (st_ver_retr),
.end_ver_retr (end_ver_retr),
.x_dotclockdiv2 (x_dotclockdiv2),
.v_retrace (v_retrace),
.vh_retrace (vh_retrace)
);
vga_cpu_mem_iface cpu_mem_iface (
.wb_clk_i (wb_clk_i),
.wb_rst_i (wb_rst_i),
.wbs_adr_i (wb_adr_i),
.wbs_sel_i (wb_sel_i),
.wbs_we_i (wb_we_i),
.wbs_dat_i (wb_dat_i),
.wbs_dat_o (mem_wb_dat_o),
.wbs_stb_i (stb & !wb_tga_i),
.wbs_ack_o (mem_wb_ack_o),
.wbm_adr_o (wbm_adr_o),
.wbm_sel_o (wbm_sel_o),
.wbm_we_o (wbm_we_o),
.wbm_dat_o (wbm_dat_o),
.wbm_dat_i (wbm_dat_i),
.wbm_stb_o (wbm_stb_o),
.wbm_ack_i (wbm_ack_i),
.chain_four (chain_four),
.memory_mapping1 (memory_mapping1),
.write_mode (write_mode),
.raster_op (raster_op),
.read_mode (read_mode),
.bitmask (bitmask),
.set_reset (set_reset),
.enable_set_reset (enable_set_reset),
.map_mask (map_mask),
.read_map_select (read_map_select),
.color_compare (color_compare),
.color_dont_care (color_dont_care)
);
vga_mem_arbitrer mem_arbitrer (
.clk_i (wb_clk_i),
.rst_i (wb_rst_i),
.wb_adr_i (wbm_adr_o),
.wb_sel_i (wbm_sel_o),
.wb_we_i (wbm_we_o),
.wb_dat_i (wbm_dat_o),
.wb_dat_o (wbm_dat_i),
.wb_stb_i (wbm_stb_o),
.wb_ack_o (wbm_ack_i),
.csr_adr_i (csr_adr_i),
.csr_dat_o (csr_dat_i),
.csr_stb_i (csr_stb_i),
.csrm_adr_o (csrm_adr_o),
.csrm_sel_o (csrm_sel_o),
.csrm_we_o (csrm_we_o),
.csrm_dat_o (csrm_dat_o),
.csrm_dat_i (csrm_dat_i)
);
// Continous assignments
assign wb_dat_o = wb_tga_i ? conf_wb_dat_o : mem_wb_dat_o;
assign wb_ack_o = wb_tga_i ? conf_wb_ack_o : mem_wb_ack_o;
assign stb = wb_stb_i & wb_cyc_i;
assign vert_sync = ~graphics_alpha ^ w_vert_sync;
// Behaviour
// csr_adr_i
always @(posedge wb_clk_i)
csr_adr_i <= wb_rst_i ? 17'h0 : csr_adr_o + start_addr[15:1];
// csr_stb_i
always @(posedge wb_clk_i)
csr_stb_i <= wb_rst_i ? 1'b0 : csr_stb_o;
endmodule |
module vga (
// Wishbone signals
input wb_clk_i, // 25 Mhz VDU clock
input wb_rst_i,
input [15:0] wb_dat_i,
output [15:0] wb_dat_o,
input [16:1] wb_adr_i,
input wb_we_i,
input wb_tga_i,
input [ 1:0] wb_sel_i,
input wb_stb_i,
input wb_cyc_i,
output wb_ack_o,
// VGA pad signals
output [ 3:0] vga_red_o,
output [ 3:0] vga_green_o,
output [ 3:0] vga_blue_o,
output horiz_sync,
output vert_sync,
// CSR SRAM master interface
output [17:1] csrm_adr_o,
output [ 1:0] csrm_sel_o,
output csrm_we_o,
output [15:0] csrm_dat_o,
input [15:0] csrm_dat_i
);
// Registers and nets
//
// csr address
reg [17:1] csr_adr_i;
reg csr_stb_i;
// Config wires
wire [15:0] conf_wb_dat_o;
wire conf_wb_ack_o;
// Mem wires
wire [15:0] mem_wb_dat_o;
wire mem_wb_ack_o;
// LCD wires
wire [17:1] csr_adr_o;
wire [15:0] csr_dat_i;
wire csr_stb_o;
wire v_retrace;
wire vh_retrace;
wire w_vert_sync;
// VGA configuration registers
wire shift_reg1;
wire graphics_alpha;
wire memory_mapping1;
wire [ 1:0] write_mode;
wire [ 1:0] raster_op;
wire read_mode;
wire [ 7:0] bitmask;
wire [ 3:0] set_reset;
wire [ 3:0] enable_set_reset;
wire [ 3:0] map_mask;
wire x_dotclockdiv2;
wire chain_four;
wire [ 1:0] read_map_select;
wire [ 3:0] color_compare;
wire [ 3:0] color_dont_care;
// Wishbone master to SRAM
wire [17:1] wbm_adr_o;
wire [ 1:0] wbm_sel_o;
wire wbm_we_o;
wire [15:0] wbm_dat_o;
wire [15:0] wbm_dat_i;
wire wbm_stb_o;
wire wbm_ack_i;
wire stb;
// CRT wires
wire [ 5:0] cur_start;
wire [ 5:0] cur_end;
wire [15:0] start_addr;
wire [ 4:0] vcursor;
wire [ 6:0] hcursor;
wire [ 6:0] horiz_total;
wire [ 6:0] end_horiz;
wire [ 6:0] st_hor_retr;
wire [ 4:0] end_hor_retr;
wire [ 9:0] vert_total;
wire [ 9:0] end_vert;
wire [ 9:0] st_ver_retr;
wire [ 3:0] end_ver_retr;
// attribute_ctrl wires
wire [3:0] pal_addr;
wire pal_we;
wire [7:0] pal_read;
wire [7:0] pal_write;
// dac_regs wires
wire dac_we;
wire [1:0] dac_read_data_cycle;
wire [7:0] dac_read_data_register;
wire [3:0] dac_read_data;
wire [1:0] dac_write_data_cycle;
wire [7:0] dac_write_data_register;
wire [3:0] dac_write_data;
// Module instances
//
vga_config_iface config_iface (
.wb_clk_i (wb_clk_i),
.wb_rst_i (wb_rst_i),
.wb_dat_i (wb_dat_i),
.wb_dat_o (conf_wb_dat_o),
.wb_adr_i (wb_adr_i[4:1]),
.wb_we_i (wb_we_i),
.wb_sel_i (wb_sel_i),
.wb_stb_i (stb & wb_tga_i),
.wb_ack_o (conf_wb_ack_o),
.shift_reg1 (shift_reg1),
.graphics_alpha (graphics_alpha),
.memory_mapping1 (memory_mapping1),
.write_mode (write_mode),
.raster_op (raster_op),
.read_mode (read_mode),
.bitmask (bitmask),
.set_reset (set_reset),
.enable_set_reset (enable_set_reset),
.map_mask (map_mask),
.x_dotclockdiv2 (x_dotclockdiv2),
.chain_four (chain_four),
.read_map_select (read_map_select),
.color_compare (color_compare),
.color_dont_care (color_dont_care),
.pal_addr (pal_addr),
.pal_we (pal_we),
.pal_read (pal_read),
.pal_write (pal_write),
.dac_we (dac_we),
.dac_read_data_cycle (dac_read_data_cycle),
.dac_read_data_register (dac_read_data_register),
.dac_read_data (dac_read_data),
.dac_write_data_cycle (dac_write_data_cycle),
.dac_write_data_register (dac_write_data_register),
.dac_write_data (dac_write_data),
.cur_start (cur_start),
.cur_end (cur_end),
.start_addr (start_addr),
.vcursor (vcursor),
.hcursor (hcursor),
.horiz_total (horiz_total),
.end_horiz (end_horiz),
.st_hor_retr (st_hor_retr),
.end_hor_retr (end_hor_retr),
.vert_total (vert_total),
.end_vert (end_vert),
.st_ver_retr (st_ver_retr),
.end_ver_retr (end_ver_retr),
.v_retrace (v_retrace),
.vh_retrace (vh_retrace)
);
vga_lcd lcd (
.clk (wb_clk_i),
.rst (wb_rst_i),
.shift_reg1 (shift_reg1),
.graphics_alpha (graphics_alpha),
.pal_addr (pal_addr),
.pal_we (pal_we),
.pal_read (pal_read),
.pal_write (pal_write),
.dac_we (dac_we),
.dac_read_data_cycle (dac_read_data_cycle),
.dac_read_data_register (dac_read_data_register),
.dac_read_data (dac_read_data),
.dac_write_data_cycle (dac_write_data_cycle),
.dac_write_data_register (dac_write_data_register),
.dac_write_data (dac_write_data),
.csr_adr_o (csr_adr_o),
.csr_dat_i (csr_dat_i),
.csr_stb_o (csr_stb_o),
.vga_red_o (vga_red_o),
.vga_green_o (vga_green_o),
.vga_blue_o (vga_blue_o),
.horiz_sync (horiz_sync),
.vert_sync (w_vert_sync),
.cur_start (cur_start),
.cur_end (cur_end),
.vcursor (vcursor),
.hcursor (hcursor),
.horiz_total (horiz_total),
.end_horiz (end_horiz),
.st_hor_retr (st_hor_retr),
.end_hor_retr (end_hor_retr),
.vert_total (vert_total),
.end_vert (end_vert),
.st_ver_retr (st_ver_retr),
.end_ver_retr (end_ver_retr),
.x_dotclockdiv2 (x_dotclockdiv2),
.v_retrace (v_retrace),
.vh_retrace (vh_retrace)
);
vga_cpu_mem_iface cpu_mem_iface (
.wb_clk_i (wb_clk_i),
.wb_rst_i (wb_rst_i),
.wbs_adr_i (wb_adr_i),
.wbs_sel_i (wb_sel_i),
.wbs_we_i (wb_we_i),
.wbs_dat_i (wb_dat_i),
.wbs_dat_o (mem_wb_dat_o),
.wbs_stb_i (stb & !wb_tga_i),
.wbs_ack_o (mem_wb_ack_o),
.wbm_adr_o (wbm_adr_o),
.wbm_sel_o (wbm_sel_o),
.wbm_we_o (wbm_we_o),
.wbm_dat_o (wbm_dat_o),
.wbm_dat_i (wbm_dat_i),
.wbm_stb_o (wbm_stb_o),
.wbm_ack_i (wbm_ack_i),
.chain_four (chain_four),
.memory_mapping1 (memory_mapping1),
.write_mode (write_mode),
.raster_op (raster_op),
.read_mode (read_mode),
.bitmask (bitmask),
.set_reset (set_reset),
.enable_set_reset (enable_set_reset),
.map_mask (map_mask),
.read_map_select (read_map_select),
.color_compare (color_compare),
.color_dont_care (color_dont_care)
);
vga_mem_arbitrer mem_arbitrer (
.clk_i (wb_clk_i),
.rst_i (wb_rst_i),
.wb_adr_i (wbm_adr_o),
.wb_sel_i (wbm_sel_o),
.wb_we_i (wbm_we_o),
.wb_dat_i (wbm_dat_o),
.wb_dat_o (wbm_dat_i),
.wb_stb_i (wbm_stb_o),
.wb_ack_o (wbm_ack_i),
.csr_adr_i (csr_adr_i),
.csr_dat_o (csr_dat_i),
.csr_stb_i (csr_stb_i),
.csrm_adr_o (csrm_adr_o),
.csrm_sel_o (csrm_sel_o),
.csrm_we_o (csrm_we_o),
.csrm_dat_o (csrm_dat_o),
.csrm_dat_i (csrm_dat_i)
);
// Continous assignments
assign wb_dat_o = wb_tga_i ? conf_wb_dat_o : mem_wb_dat_o;
assign wb_ack_o = wb_tga_i ? conf_wb_ack_o : mem_wb_ack_o;
assign stb = wb_stb_i & wb_cyc_i;
assign vert_sync = ~graphics_alpha ^ w_vert_sync;
// Behaviour
// csr_adr_i
always @(posedge wb_clk_i)
csr_adr_i <= wb_rst_i ? 17'h0 : csr_adr_o + start_addr[15:1];
// csr_stb_i
always @(posedge wb_clk_i)
csr_stb_i <= wb_rst_i ? 1'b0 : csr_stb_o;
endmodule |
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