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corundum/rtl/axis_pipeline_fifo.v
2021-10-20 15:33:38 -07:00

261 lines
9.8 KiB
Verilog

/*
Copyright (c) 2021 Alex Forencich
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/
// Language: Verilog 2001
`resetall
`timescale 1ns / 1ps
`default_nettype none
/*
* AXI4-Stream pipeline FIFO
*/
module axis_pipeline_fifo #
(
// Width of AXI stream interfaces in bits
parameter DATA_WIDTH = 8,
// Propagate tkeep signal
parameter KEEP_ENABLE = (DATA_WIDTH>8),
// tkeep signal width (words per cycle)
parameter KEEP_WIDTH = (DATA_WIDTH/8),
// Propagate tlast signal
parameter LAST_ENABLE = 1,
// Propagate tid signal
parameter ID_ENABLE = 0,
// tid signal width
parameter ID_WIDTH = 8,
// Propagate tdest signal
parameter DEST_ENABLE = 0,
// tdest signal width
parameter DEST_WIDTH = 8,
// Propagate tuser signal
parameter USER_ENABLE = 1,
// tuser signal width
parameter USER_WIDTH = 1,
// Number of registers in pipeline
parameter LENGTH = 2
)
(
input wire clk,
input wire rst,
/*
* AXI input
*/
input wire [DATA_WIDTH-1:0] s_axis_tdata,
input wire [KEEP_WIDTH-1:0] s_axis_tkeep,
input wire s_axis_tvalid,
output wire s_axis_tready,
input wire s_axis_tlast,
input wire [ID_WIDTH-1:0] s_axis_tid,
input wire [DEST_WIDTH-1:0] s_axis_tdest,
input wire [USER_WIDTH-1:0] s_axis_tuser,
/*
* AXI output
*/
output wire [DATA_WIDTH-1:0] m_axis_tdata,
output wire [KEEP_WIDTH-1:0] m_axis_tkeep,
output wire m_axis_tvalid,
input wire m_axis_tready,
output wire m_axis_tlast,
output wire [ID_WIDTH-1:0] m_axis_tid,
output wire [DEST_WIDTH-1:0] m_axis_tdest,
output wire [USER_WIDTH-1:0] m_axis_tuser
);
parameter FIFO_ADDR_WIDTH = LENGTH < 2 ? 3 : $clog2(LENGTH*4+1);
generate
if (LENGTH > 0) begin
// pipeline
(* shreg_extract = "no" *)
reg [DATA_WIDTH-1:0] axis_tdata_reg[0:LENGTH-1];
(* shreg_extract = "no" *)
reg [KEEP_WIDTH-1:0] axis_tkeep_reg[0:LENGTH-1];
(* shreg_extract = "no" *)
reg axis_tvalid_reg[0:LENGTH-1];
(* shreg_extract = "no" *)
reg axis_tready_reg[0:LENGTH-1];
(* shreg_extract = "no" *)
reg axis_tlast_reg[0:LENGTH-1];
(* shreg_extract = "no" *)
reg [ID_WIDTH-1:0] axis_tid_reg[0:LENGTH-1];
(* shreg_extract = "no" *)
reg [DEST_WIDTH-1:0] axis_tdest_reg[0:LENGTH-1];
(* shreg_extract = "no" *)
reg [USER_WIDTH-1:0] axis_tuser_reg[0:LENGTH-1];
wire [DATA_WIDTH-1:0] m_axis_tdata_int = axis_tdata_reg[LENGTH-1];
wire [KEEP_WIDTH-1:0] m_axis_tkeep_int = axis_tkeep_reg[LENGTH-1];
wire m_axis_tvalid_int = axis_tvalid_reg[LENGTH-1];
wire m_axis_tready_int;
wire m_axis_tlast_int = axis_tlast_reg[LENGTH-1];
wire [ID_WIDTH-1:0] m_axis_tid_int = axis_tid_reg[LENGTH-1];
wire [DEST_WIDTH-1:0] m_axis_tdest_int = axis_tdest_reg[LENGTH-1];
wire [USER_WIDTH-1:0] m_axis_tuser_int = axis_tuser_reg[LENGTH-1];
assign s_axis_tready = axis_tready_reg[0];
integer i;
initial begin
for (i = 0; i < LENGTH; i = i + 1) begin
axis_tdata_reg[i] = {DATA_WIDTH{1'b0}};
axis_tkeep_reg[i] = {KEEP_WIDTH{1'b0}};
axis_tvalid_reg[i] = 1'b0;
axis_tready_reg[i] = 1'b0;
axis_tlast_reg[i] = 1'b0;
axis_tid_reg[i] = {ID_WIDTH{1'b0}};
axis_tdest_reg[i] = {DEST_WIDTH{1'b0}};
axis_tuser_reg[i] = {USER_WIDTH{1'b0}};
end
end
always @(posedge clk) begin
axis_tdata_reg[0] <= s_axis_tdata;
axis_tkeep_reg[0] <= s_axis_tkeep;
axis_tvalid_reg[0] <= s_axis_tvalid && s_axis_tready;
axis_tlast_reg[0] <= s_axis_tlast;
axis_tid_reg[0] <= s_axis_tid;
axis_tdest_reg[0] <= s_axis_tdest;
axis_tuser_reg[0] <= s_axis_tuser;
axis_tready_reg[LENGTH-1] <= m_axis_tready_int;
for (i = 0; i < LENGTH-1; i = i + 1) begin
axis_tdata_reg[i+1] <= axis_tdata_reg[i];
axis_tkeep_reg[i+1] <= axis_tkeep_reg[i];
axis_tvalid_reg[i+1] <= axis_tvalid_reg[i];
axis_tlast_reg[i+1] <= axis_tlast_reg[i];
axis_tid_reg[i+1] <= axis_tid_reg[i];
axis_tdest_reg[i+1] <= axis_tdest_reg[i];
axis_tuser_reg[i+1] <= axis_tuser_reg[i];
axis_tready_reg[i] <= axis_tready_reg[i+1];
end
if (rst) begin
for (i = 0; i < LENGTH; i = i + 1) begin
axis_tvalid_reg[i] <= 1'b0;
axis_tready_reg[i] <= 1'b0;
end
end
end
// output datapath logic
reg [DATA_WIDTH-1:0] m_axis_tdata_reg = {DATA_WIDTH{1'b0}};
reg [KEEP_WIDTH-1:0] m_axis_tkeep_reg = {KEEP_WIDTH{1'b0}};
reg m_axis_tvalid_reg = 1'b0;
reg m_axis_tlast_reg = 1'b0;
reg [ID_WIDTH-1:0] m_axis_tid_reg = {ID_WIDTH{1'b0}};
reg [DEST_WIDTH-1:0] m_axis_tdest_reg = {DEST_WIDTH{1'b0}};
reg [USER_WIDTH-1:0] m_axis_tuser_reg = {USER_WIDTH{1'b0}};
reg [FIFO_ADDR_WIDTH+1-1:0] out_fifo_wr_ptr_reg = 0;
reg [FIFO_ADDR_WIDTH+1-1:0] out_fifo_rd_ptr_reg = 0;
reg out_fifo_half_full_reg = 1'b0;
wire out_fifo_full = out_fifo_wr_ptr_reg == (out_fifo_rd_ptr_reg ^ {1'b1, {FIFO_ADDR_WIDTH{1'b0}}});
wire out_fifo_empty = out_fifo_wr_ptr_reg == out_fifo_rd_ptr_reg;
(* ram_style = "distributed" *)
reg [DATA_WIDTH-1:0] out_fifo_tdata[2**FIFO_ADDR_WIDTH-1:0];
(* ram_style = "distributed" *)
reg [KEEP_WIDTH-1:0] out_fifo_tkeep[2**FIFO_ADDR_WIDTH-1:0];
(* ram_style = "distributed" *)
reg out_fifo_tlast[2**FIFO_ADDR_WIDTH-1:0];
(* ram_style = "distributed" *)
reg [ID_WIDTH-1:0] out_fifo_tid[2**FIFO_ADDR_WIDTH-1:0];
(* ram_style = "distributed" *)
reg [DEST_WIDTH-1:0] out_fifo_tdest[2**FIFO_ADDR_WIDTH-1:0];
(* ram_style = "distributed" *)
reg [USER_WIDTH-1:0] out_fifo_tuser[2**FIFO_ADDR_WIDTH-1:0];
assign m_axis_tready_int = !out_fifo_half_full_reg;
assign m_axis_tdata = m_axis_tdata_reg;
assign m_axis_tkeep = KEEP_ENABLE ? m_axis_tkeep_reg : {KEEP_WIDTH{1'b1}};
assign m_axis_tvalid = m_axis_tvalid_reg;
assign m_axis_tlast = LAST_ENABLE ? m_axis_tlast_reg : 1'b1;
assign m_axis_tid = ID_ENABLE ? m_axis_tid_reg : {ID_WIDTH{1'b0}};
assign m_axis_tdest = DEST_ENABLE ? m_axis_tdest_reg : {DEST_WIDTH{1'b0}};
assign m_axis_tuser = USER_ENABLE ? m_axis_tuser_reg : {USER_WIDTH{1'b0}};
always @(posedge clk) begin
m_axis_tvalid_reg <= m_axis_tvalid_reg && !m_axis_tready;
out_fifo_half_full_reg <= $unsigned(out_fifo_wr_ptr_reg - out_fifo_rd_ptr_reg) >= 2**(FIFO_ADDR_WIDTH-1);
if (!out_fifo_full && m_axis_tvalid_int) begin
out_fifo_tdata[out_fifo_wr_ptr_reg[FIFO_ADDR_WIDTH-1:0]] <= m_axis_tdata_int;
out_fifo_tkeep[out_fifo_wr_ptr_reg[FIFO_ADDR_WIDTH-1:0]] <= m_axis_tkeep_int;
out_fifo_tlast[out_fifo_wr_ptr_reg[FIFO_ADDR_WIDTH-1:0]] <= m_axis_tlast_int;
out_fifo_tid[out_fifo_wr_ptr_reg[FIFO_ADDR_WIDTH-1:0]] <= m_axis_tid_int;
out_fifo_tdest[out_fifo_wr_ptr_reg[FIFO_ADDR_WIDTH-1:0]] <= m_axis_tdest_int;
out_fifo_tuser[out_fifo_wr_ptr_reg[FIFO_ADDR_WIDTH-1:0]] <= m_axis_tuser_int;
out_fifo_wr_ptr_reg <= out_fifo_wr_ptr_reg + 1;
end
if (!out_fifo_empty && (!m_axis_tvalid_reg || m_axis_tready)) begin
m_axis_tdata_reg <= out_fifo_tdata[out_fifo_rd_ptr_reg[FIFO_ADDR_WIDTH-1:0]];
m_axis_tkeep_reg <= out_fifo_tkeep[out_fifo_rd_ptr_reg[FIFO_ADDR_WIDTH-1:0]];
m_axis_tvalid_reg <= 1'b1;
m_axis_tlast_reg <= out_fifo_tlast[out_fifo_rd_ptr_reg[FIFO_ADDR_WIDTH-1:0]];
m_axis_tid_reg <= out_fifo_tid[out_fifo_rd_ptr_reg[FIFO_ADDR_WIDTH-1:0]];
m_axis_tdest_reg <= out_fifo_tdest[out_fifo_rd_ptr_reg[FIFO_ADDR_WIDTH-1:0]];
m_axis_tuser_reg <= out_fifo_tuser[out_fifo_rd_ptr_reg[FIFO_ADDR_WIDTH-1:0]];
out_fifo_rd_ptr_reg <= out_fifo_rd_ptr_reg + 1;
end
if (rst) begin
out_fifo_wr_ptr_reg <= 0;
out_fifo_rd_ptr_reg <= 0;
m_axis_tvalid_reg <= 1'b0;
end
end
end else begin
// bypass
assign m_axis_tdata = s_axis_tdata;
assign m_axis_tkeep = KEEP_ENABLE ? s_axis_tkeep : {KEEP_WIDTH{1'b1}};
assign m_axis_tvalid = s_axis_tvalid;
assign m_axis_tlast = LAST_ENABLE ? s_axis_tlast : 1'b1;
assign m_axis_tid = ID_ENABLE ? s_axis_tid : {ID_WIDTH{1'b0}};
assign m_axis_tdest = DEST_ENABLE ? s_axis_tdest : {DEST_WIDTH{1'b0}};
assign m_axis_tuser = USER_ENABLE ? s_axis_tuser : {USER_WIDTH{1'b0}};
assign s_axis_tready = m_axis_tready;
end
endgenerate
endmodule
`resetall