axi: Add AXI lite register module and testbench

Signed-off-by: Alex Forencich <alex@alexforencich.com>
This commit is contained in:
Alex Forencich
2025-02-26 21:02:50 -08:00
parent 5e5bce9aa0
commit 1075896ecc
7 changed files with 1384 additions and 0 deletions

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taxi_axil_register.sv
taxi_axil_register_wr.sv
taxi_axil_register_rd.sv
taxi_axil_if.sv

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// SPDX-License-Identifier: CERN-OHL-S-2.0
/*
Copyright (c) 2018-2025 FPGA Ninja, LLC
Authors:
- Alex Forencich
*/
`resetall
`timescale 1ns / 1ps
`default_nettype none
/*
* AXI4 lite register
*/
module taxi_axil_register #
(
// AW channel register type
// 0 to bypass, 1 for simple buffer
parameter AW_REG_TYPE = 1,
// W channel register type
// 0 to bypass, 1 for simple buffer
parameter W_REG_TYPE = 1,
// B channel register type
// 0 to bypass, 1 for simple buffer
parameter B_REG_TYPE = 1,
// AR channel register type
// 0 to bypass, 1 for simple buffer
parameter AR_REG_TYPE = 1,
// R channel register type
// 0 to bypass, 1 for simple buffer
parameter R_REG_TYPE = 1
)
(
input wire logic clk,
input wire logic rst,
/*
* AXI4-Lite slave interface
*/
taxi_axil_if.wr_slv s_axil_wr,
taxi_axil_if.rd_slv s_axil_rd,
/*
* AXI4-Lite master interface
*/
taxi_axil_if.wr_mst m_axil_wr,
taxi_axil_if.rd_mst m_axil_rd
);
taxi_axil_register_wr #(
.AW_REG_TYPE(AW_REG_TYPE),
.W_REG_TYPE(W_REG_TYPE),
.B_REG_TYPE(B_REG_TYPE)
)
axil_register_wr_inst (
.clk(clk),
.rst(rst),
/*
* AXI4-Lite slave interface
*/
.s_axil_wr(s_axil_wr),
/*
* AXI4-Lite master interface
*/
.m_axil_wr(m_axil_wr)
);
taxi_axil_register_rd #(
.AR_REG_TYPE(AR_REG_TYPE),
.R_REG_TYPE(R_REG_TYPE)
)
axil_register_rd_inst (
.clk(clk),
.rst(rst),
/*
* AXI4-Lite slave interface
*/
.s_axil_rd(s_axil_rd),
/*
* AXI4-Lite master interface
*/
.m_axil_rd(m_axil_rd)
);
endmodule
`resetall

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// SPDX-License-Identifier: CERN-OHL-S-2.0
/*
Copyright (c) 2018-2025 FPGA Ninja, LLC
Authors:
- Alex Forencich
*/
`resetall
`timescale 1ns / 1ps
`default_nettype none
/*
* AXI4 lite register (read)
*/
module taxi_axil_register_rd #
(
// AR channel register type
// 0 to bypass, 1 for simple buffer
parameter AR_REG_TYPE = 1,
// R channel register type
// 0 to bypass, 1 for simple buffer
parameter R_REG_TYPE = 1
)
(
input wire logic clk,
input wire logic rst,
/*
* AXI4-Lite slave interface
*/
taxi_axil_if.rd_slv s_axil_rd,
/*
* AXI4-Lite master interface
*/
taxi_axil_if.rd_mst m_axil_rd
);
// extract parameters
localparam DATA_W = s_axil_rd.DATA_W;
localparam ADDR_W = s_axil_rd.ADDR_W;
localparam STRB_W = s_axil_rd.STRB_W;
localparam logic ARUSER_EN = s_axil_rd.ARUSER_EN && m_axil_rd.ARUSER_EN;
localparam ARUSER_W = s_axil_rd.ARUSER_W;
localparam logic RUSER_EN = s_axil_rd.RUSER_EN && m_axil_rd.RUSER_EN;
localparam RUSER_W = s_axil_rd.RUSER_W;
if (m_axil_rd.DATA_W != DATA_W)
$fatal(0, "Error: Interface DATA_W parameter mismatch (instance %m)");
if (m_axil_rd.STRB_W != STRB_W)
$fatal(0, "Error: Interface STRB_W parameter mismatch (instance %m)");
// AR channel
if (AR_REG_TYPE > 1) begin
// skid buffer, no bubble cycles
// datapath registers
logic s_axil_arready_reg = 1'b0;
logic [ADDR_W-1:0] m_axil_araddr_reg = '0;
logic [2:0] m_axil_arprot_reg = '0;
logic [ARUSER_W-1:0] m_axil_aruser_reg = '0;
logic m_axil_arvalid_reg = 1'b0, m_axil_arvalid_next;
logic [ADDR_W-1:0] temp_m_axil_araddr_reg = '0;
logic [2:0] temp_m_axil_arprot_reg = '0;
logic [ARUSER_W-1:0] temp_m_axil_aruser_reg = '0;
logic temp_m_axil_arvalid_reg = 1'b0, temp_m_axil_arvalid_next;
// datapath control
logic store_axil_ar_input_to_output;
logic store_axil_ar_input_to_temp;
logic store_axil_ar_temp_to_output;
assign s_axil_rd.arready = s_axil_arready_reg;
assign m_axil_rd.araddr = m_axil_araddr_reg;
assign m_axil_rd.arprot = m_axil_arprot_reg;
assign m_axil_rd.aruser = ARUSER_EN ? m_axil_aruser_reg : '0;
assign m_axil_rd.arvalid = m_axil_arvalid_reg;
// enable ready input next cycle if output is ready or the temp reg will not be filled on the next cycle (output reg empty or no input)
wire s_axil_arready_early = m_axil_rd.arready || (!temp_m_axil_arvalid_reg && (!m_axil_arvalid_reg || !s_axil_rd.arvalid));
always_comb begin
// transfer sink ready state to source
m_axil_arvalid_next = m_axil_arvalid_reg;
temp_m_axil_arvalid_next = temp_m_axil_arvalid_reg;
store_axil_ar_input_to_output = 1'b0;
store_axil_ar_input_to_temp = 1'b0;
store_axil_ar_temp_to_output = 1'b0;
if (s_axil_arready_reg) begin
// input is ready
if (m_axil_rd.arready || !m_axil_arvalid_reg) begin
// output is ready or currently not valid, transfer data to output
m_axil_arvalid_next = s_axil_rd.arvalid;
store_axil_ar_input_to_output = 1'b1;
end else begin
// output is not ready, store input in temp
temp_m_axil_arvalid_next = s_axil_rd.arvalid;
store_axil_ar_input_to_temp = 1'b1;
end
end else if (m_axil_rd.arready) begin
// input is not ready, but output is ready
m_axil_arvalid_next = temp_m_axil_arvalid_reg;
temp_m_axil_arvalid_next = 1'b0;
store_axil_ar_temp_to_output = 1'b1;
end
end
always_ff @(posedge clk) begin
s_axil_arready_reg <= s_axil_arready_early;
m_axil_arvalid_reg <= m_axil_arvalid_next;
temp_m_axil_arvalid_reg <= temp_m_axil_arvalid_next;
// datapath
if (store_axil_ar_input_to_output) begin
m_axil_araddr_reg <= s_axil_rd.araddr;
m_axil_arprot_reg <= s_axil_rd.arprot;
m_axil_aruser_reg <= s_axil_rd.aruser;
end else if (store_axil_ar_temp_to_output) begin
m_axil_araddr_reg <= temp_m_axil_araddr_reg;
m_axil_arprot_reg <= temp_m_axil_arprot_reg;
m_axil_aruser_reg <= temp_m_axil_aruser_reg;
end
if (store_axil_ar_input_to_temp) begin
temp_m_axil_araddr_reg <= s_axil_rd.araddr;
temp_m_axil_arprot_reg <= s_axil_rd.arprot;
temp_m_axil_aruser_reg <= s_axil_rd.aruser;
end
if (rst) begin
s_axil_arready_reg <= 1'b0;
m_axil_arvalid_reg <= 1'b0;
temp_m_axil_arvalid_reg <= 1'b0;
end
end
end else if (AR_REG_TYPE == 1) begin
// simple register, inserts bubble cycles
// datapath registers
logic s_axil_arready_reg = 1'b0;
logic [ADDR_W-1:0] m_axil_araddr_reg = '0;
logic [2:0] m_axil_arprot_reg = '0;
logic [ARUSER_W-1:0] m_axil_aruser_reg = '0;
logic m_axil_arvalid_reg = 1'b0, m_axil_arvalid_next;
// datapath control
logic store_axil_ar_input_to_output;
assign s_axil_rd.arready = s_axil_arready_reg;
assign m_axil_rd.araddr = m_axil_araddr_reg;
assign m_axil_rd.arprot = m_axil_arprot_reg;
assign m_axil_rd.aruser = ARUSER_EN ? m_axil_aruser_reg : '0;
assign m_axil_rd.arvalid = m_axil_arvalid_reg;
// enable ready input next cycle if output buffer will be empty
wire s_axil_arready_early = !m_axil_arvalid_next;
always_comb begin
// transfer sink ready state to source
m_axil_arvalid_next = m_axil_arvalid_reg;
store_axil_ar_input_to_output = 1'b0;
if (s_axil_arready_reg) begin
m_axil_arvalid_next = s_axil_rd.arvalid;
store_axil_ar_input_to_output = 1'b1;
end else if (m_axil_rd.arready) begin
m_axil_arvalid_next = 1'b0;
end
end
always_ff @(posedge clk) begin
s_axil_arready_reg <= s_axil_arready_early;
m_axil_arvalid_reg <= m_axil_arvalid_next;
// datapath
if (store_axil_ar_input_to_output) begin
m_axil_araddr_reg <= s_axil_rd.araddr;
m_axil_arprot_reg <= s_axil_rd.arprot;
m_axil_aruser_reg <= s_axil_rd.aruser;
end
if (rst) begin
s_axil_arready_reg <= 1'b0;
m_axil_arvalid_reg <= 1'b0;
end
end
end else begin
// bypass AR channel
assign m_axil_rd.araddr = s_axil_rd.araddr;
assign m_axil_rd.arprot = s_axil_rd.arprot;
assign m_axil_rd.aruser = ARUSER_EN ? s_axil_rd.aruser : '0;
assign m_axil_rd.arvalid = s_axil_rd.arvalid;
assign s_axil_rd.arready = m_axil_rd.arready;
end
// R channel
if (R_REG_TYPE > 1) begin
// skid buffer, no bubble cycles
// datapath registers
logic m_axil_rready_reg = 1'b0;
logic [DATA_W-1:0] s_axil_rdata_reg = '0;
logic [1:0] s_axil_rresp_reg = 2'b0;
logic [RUSER_W-1:0] s_axil_ruser_reg = '0;
logic s_axil_rvalid_reg = 1'b0, s_axil_rvalid_next;
logic [DATA_W-1:0] temp_s_axil_rdata_reg = '0;
logic [1:0] temp_s_axil_rresp_reg = 2'b0;
logic [RUSER_W-1:0] temp_s_axil_ruser_reg = '0;
logic temp_s_axil_rvalid_reg = 1'b0, temp_s_axil_rvalid_next;
// datapath control
logic store_axil_r_input_to_output;
logic store_axil_r_input_to_temp;
logic store_axil_r_temp_to_output;
assign m_axil_rd.rready = m_axil_rready_reg;
assign s_axil_rd.rdata = s_axil_rdata_reg;
assign s_axil_rd.rresp = s_axil_rresp_reg;
assign s_axil_rd.ruser = RUSER_EN ? s_axil_ruser_reg : '0;
assign s_axil_rd.rvalid = s_axil_rvalid_reg;
// enable ready input next cycle if output is ready or the temp reg will not be filled on the next cycle (output reg empty or no input)
wire m_axil_rready_early = s_axil_rd.rready || (!temp_s_axil_rvalid_reg && (!s_axil_rvalid_reg || !m_axil_rd.rvalid));
always_comb begin
// transfer sink ready state to source
s_axil_rvalid_next = s_axil_rvalid_reg;
temp_s_axil_rvalid_next = temp_s_axil_rvalid_reg;
store_axil_r_input_to_output = 1'b0;
store_axil_r_input_to_temp = 1'b0;
store_axil_r_temp_to_output = 1'b0;
if (m_axil_rready_reg) begin
// input is ready
if (s_axil_rd.rready || !s_axil_rvalid_reg) begin
// output is ready or currently not valid, transfer data to output
s_axil_rvalid_next = m_axil_rd.rvalid;
store_axil_r_input_to_output = 1'b1;
end else begin
// output is not ready, store input in temp
temp_s_axil_rvalid_next = m_axil_rd.rvalid;
store_axil_r_input_to_temp = 1'b1;
end
end else if (s_axil_rd.rready) begin
// input is not ready, but output is ready
s_axil_rvalid_next = temp_s_axil_rvalid_reg;
temp_s_axil_rvalid_next = 1'b0;
store_axil_r_temp_to_output = 1'b1;
end
end
always_ff @(posedge clk) begin
m_axil_rready_reg <= m_axil_rready_early;
s_axil_rvalid_reg <= s_axil_rvalid_next;
temp_s_axil_rvalid_reg <= temp_s_axil_rvalid_next;
// datapath
if (store_axil_r_input_to_output) begin
s_axil_rdata_reg <= m_axil_rd.rdata;
s_axil_rresp_reg <= m_axil_rd.rresp;
s_axil_ruser_reg <= m_axil_rd.ruser;
end else if (store_axil_r_temp_to_output) begin
s_axil_rdata_reg <= temp_s_axil_rdata_reg;
s_axil_rresp_reg <= temp_s_axil_rresp_reg;
s_axil_ruser_reg <= temp_s_axil_ruser_reg;
end
if (store_axil_r_input_to_temp) begin
temp_s_axil_rdata_reg <= m_axil_rd.rdata;
temp_s_axil_rresp_reg <= m_axil_rd.rresp;
temp_s_axil_ruser_reg <= m_axil_rd.ruser;
end
if (rst) begin
m_axil_rready_reg <= 1'b0;
s_axil_rvalid_reg <= 1'b0;
temp_s_axil_rvalid_reg <= 1'b0;
end
end
end else if (R_REG_TYPE == 1) begin
// simple register, inserts bubble cycles
// datapath registers
logic m_axil_rready_reg = 1'b0;
logic [DATA_W-1:0] s_axil_rdata_reg = '0;
logic [1:0] s_axil_rresp_reg = 2'b0;
logic [RUSER_W-1:0] s_axil_ruser_reg = '0;
logic s_axil_rvalid_reg = 1'b0, s_axil_rvalid_next;
// datapath control
logic store_axil_r_input_to_output;
assign m_axil_rd.rready = m_axil_rready_reg;
assign s_axil_rd.rdata = s_axil_rdata_reg;
assign s_axil_rd.rresp = s_axil_rresp_reg;
assign s_axil_rd.ruser = RUSER_EN ? s_axil_ruser_reg : '0;
assign s_axil_rd.rvalid = s_axil_rvalid_reg;
// enable ready input next cycle if output buffer will be empty
wire m_axil_rready_early = !s_axil_rvalid_next;
always_comb begin
// transfer sink ready state to source
s_axil_rvalid_next = s_axil_rvalid_reg;
store_axil_r_input_to_output = 1'b0;
if (m_axil_rready_reg) begin
s_axil_rvalid_next = m_axil_rd.rvalid;
store_axil_r_input_to_output = 1'b1;
end else if (s_axil_rd.rready) begin
s_axil_rvalid_next = 1'b0;
end
end
always_ff @(posedge clk) begin
m_axil_rready_reg <= m_axil_rready_early;
s_axil_rvalid_reg <= s_axil_rvalid_next;
// datapath
if (store_axil_r_input_to_output) begin
s_axil_rdata_reg <= m_axil_rd.rdata;
s_axil_rresp_reg <= m_axil_rd.rresp;
s_axil_ruser_reg <= m_axil_rd.ruser;
end
if (rst) begin
m_axil_rready_reg <= 1'b0;
s_axil_rvalid_reg <= 1'b0;
end
end
end else begin
// bypass R channel
assign s_axil_rd.rdata = m_axil_rd.rdata;
assign s_axil_rd.rresp = m_axil_rd.rresp;
assign s_axil_rd.ruser = RUSER_EN ? m_axil_rd.ruser : '0;
assign s_axil_rd.rvalid = m_axil_rd.rvalid;
assign m_axil_rd.rready = s_axil_rd.rready;
end
endmodule
`resetall

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// SPDX-License-Identifier: CERN-OHL-S-2.0
/*
Copyright (c) 2018-2025 FPGA Ninja, LLC
Authors:
- Alex Forencich
*/
`resetall
`timescale 1ns / 1ps
`default_nettype none
/*
* AXI4 lite register (write)
*/
module taxi_axil_register_wr #
(
// AW channel register type
// 0 to bypass, 1 for simple buffer
parameter AW_REG_TYPE = 1,
// W channel register type
// 0 to bypass, 1 for simple buffer
parameter W_REG_TYPE = 1,
// B channel register type
// 0 to bypass, 1 for simple buffer
parameter B_REG_TYPE = 1
)
(
input wire logic clk,
input wire logic rst,
/*
* AXI4-Lite slave interface
*/
taxi_axil_if.wr_slv s_axil_wr,
/*
* AXI4-Lite master interface
*/
taxi_axil_if.wr_mst m_axil_wr
);
// extract parameters
localparam DATA_W = s_axil_wr.DATA_W;
localparam ADDR_W = s_axil_wr.ADDR_W;
localparam STRB_W = s_axil_wr.STRB_W;
localparam logic AWUSER_EN = s_axil_wr.AWUSER_EN && m_axil_wr.AWUSER_EN;
localparam AWUSER_W = s_axil_wr.AWUSER_W;
localparam logic WUSER_EN = s_axil_wr.WUSER_EN && m_axil_wr.WUSER_EN;
localparam WUSER_W = s_axil_wr.WUSER_W;
localparam logic BUSER_EN = s_axil_wr.BUSER_EN && m_axil_wr.BUSER_EN;
localparam BUSER_W = s_axil_wr.BUSER_W;
if (m_axil_wr.DATA_W != DATA_W)
$fatal(0, "Error: Interface DATA_W parameter mismatch (instance %m)");
if (m_axil_wr.STRB_W != STRB_W)
$fatal(0, "Error: Interface STRB_W parameter mismatch (instance %m)");
// AW channel
if (AW_REG_TYPE > 1) begin
// skid buffer, no bubble cycles
// datapath registers
logic s_axil_awready_reg = 1'b0;
logic [ADDR_W-1:0] m_axil_awaddr_reg = '0;
logic [2:0] m_axil_awprot_reg = '0;
logic [AWUSER_W-1:0] m_axil_awuser_reg = '0;
logic m_axil_awvalid_reg = 1'b0, m_axil_awvalid_next;
logic [ADDR_W-1:0] temp_m_axil_awaddr_reg = '0;
logic [2:0] temp_m_axil_awprot_reg = '0;
logic [AWUSER_W-1:0] temp_m_axil_awuser_reg = '0;
logic temp_m_axil_awvalid_reg = 1'b0, temp_m_axil_awvalid_next;
// datapath control
logic store_axil_aw_input_to_output;
logic store_axil_aw_input_to_temp;
logic store_axil_aw_temp_to_output;
assign s_axil_wr.awready = s_axil_awready_reg;
assign m_axil_wr.awaddr = m_axil_awaddr_reg;
assign m_axil_wr.awprot = m_axil_awprot_reg;
assign m_axil_wr.awuser = AWUSER_EN ? m_axil_awuser_reg : '0;
assign m_axil_wr.awvalid = m_axil_awvalid_reg;
// enable ready input next cycle if output is ready or the temp reg will not be filled on the next cycle (output reg empty or no input)
wire s_axil_awready_early = m_axil_wr.awready || (!temp_m_axil_awvalid_reg && (!m_axil_awvalid_reg || !s_axil_wr.awvalid));
always_comb begin
// transfer sink ready state to source
m_axil_awvalid_next = m_axil_awvalid_reg;
temp_m_axil_awvalid_next = temp_m_axil_awvalid_reg;
store_axil_aw_input_to_output = 1'b0;
store_axil_aw_input_to_temp = 1'b0;
store_axil_aw_temp_to_output = 1'b0;
if (s_axil_awready_reg) begin
// input is ready
if (m_axil_wr.awready || !m_axil_awvalid_reg) begin
// output is ready or currently not valid, transfer data to output
m_axil_awvalid_next = s_axil_wr.awvalid;
store_axil_aw_input_to_output = 1'b1;
end else begin
// output is not ready, store input in temp
temp_m_axil_awvalid_next = s_axil_wr.awvalid;
store_axil_aw_input_to_temp = 1'b1;
end
end else if (m_axil_wr.awready) begin
// input is not ready, but output is ready
m_axil_awvalid_next = temp_m_axil_awvalid_reg;
temp_m_axil_awvalid_next = 1'b0;
store_axil_aw_temp_to_output = 1'b1;
end
end
always_ff @(posedge clk) begin
s_axil_awready_reg <= s_axil_awready_early;
m_axil_awvalid_reg <= m_axil_awvalid_next;
temp_m_axil_awvalid_reg <= temp_m_axil_awvalid_next;
// datapath
if (store_axil_aw_input_to_output) begin
m_axil_awaddr_reg <= s_axil_wr.awaddr;
m_axil_awprot_reg <= s_axil_wr.awprot;
m_axil_awuser_reg <= s_axil_wr.awuser;
end else if (store_axil_aw_temp_to_output) begin
m_axil_awaddr_reg <= temp_m_axil_awaddr_reg;
m_axil_awprot_reg <= temp_m_axil_awprot_reg;
m_axil_awuser_reg <= temp_m_axil_awuser_reg;
end
if (store_axil_aw_input_to_temp) begin
temp_m_axil_awaddr_reg <= s_axil_wr.awaddr;
temp_m_axil_awprot_reg <= s_axil_wr.awprot;
temp_m_axil_awuser_reg <= s_axil_wr.awuser;
end
if (rst) begin
s_axil_awready_reg <= 1'b0;
m_axil_awvalid_reg <= 1'b0;
temp_m_axil_awvalid_reg <= 1'b0;
end
end
end else if (AW_REG_TYPE == 1) begin
// simple register, inserts bubble cycles
// datapath registers
logic s_axil_awready_reg = 1'b0;
logic [ADDR_W-1:0] m_axil_awaddr_reg = '0;
logic [2:0] m_axil_awprot_reg = '0;
logic [AWUSER_W-1:0] m_axil_awuser_reg = '0;
logic m_axil_awvalid_reg = 1'b0, m_axil_awvalid_next;
// datapath control
logic store_axil_aw_input_to_output;
assign s_axil_wr.awready = s_axil_awready_reg;
assign m_axil_wr.awaddr = m_axil_awaddr_reg;
assign m_axil_wr.awprot = m_axil_awprot_reg;
assign m_axil_wr.awuser = AWUSER_EN ? m_axil_awuser_reg : '0;
assign m_axil_wr.awvalid = m_axil_awvalid_reg;
// enable ready input next cycle if output buffer will be empty
wire s_axil_awready_early = !m_axil_awvalid_next;
always_comb begin
// transfer sink ready state to source
m_axil_awvalid_next = m_axil_awvalid_reg;
store_axil_aw_input_to_output = 1'b0;
if (s_axil_awready_reg) begin
m_axil_awvalid_next = s_axil_wr.awvalid;
store_axil_aw_input_to_output = 1'b1;
end else if (m_axil_wr.awready) begin
m_axil_awvalid_next = 1'b0;
end
end
always_ff @(posedge clk) begin
s_axil_awready_reg <= s_axil_awready_early;
m_axil_awvalid_reg <= m_axil_awvalid_next;
// datapath
if (store_axil_aw_input_to_output) begin
m_axil_awaddr_reg <= s_axil_wr.awaddr;
m_axil_awprot_reg <= s_axil_wr.awprot;
m_axil_awuser_reg <= s_axil_wr.awuser;
end
if (rst) begin
s_axil_awready_reg <= 1'b0;
m_axil_awvalid_reg <= 1'b0;
end
end
end else begin
// bypass AW channel
assign m_axil_wr.awaddr = s_axil_wr.awaddr;
assign m_axil_wr.awprot = s_axil_wr.awprot;
assign m_axil_wr.awuser = AWUSER_EN ? s_axil_wr.awuser : '0;
assign m_axil_wr.awvalid = s_axil_wr.awvalid;
assign s_axil_wr.awready = m_axil_wr.awready;
end
// W channel
if (W_REG_TYPE > 1) begin
// skid buffer, no bubble cycles
// datapath registers
logic s_axil_wready_reg = 1'b0;
logic [DATA_W-1:0] m_axil_wdata_reg = '0;
logic [STRB_W-1:0] m_axil_wstrb_reg = '0;
logic [WUSER_W-1:0] m_axil_wuser_reg = '0;
logic m_axil_wvalid_reg = 1'b0, m_axil_wvalid_next;
logic [DATA_W-1:0] temp_m_axil_wdata_reg = '0;
logic [STRB_W-1:0] temp_m_axil_wstrb_reg = '0;
logic [WUSER_W-1:0] temp_m_axil_wuser_reg = '0;
logic temp_m_axil_wvalid_reg = 1'b0, temp_m_axil_wvalid_next;
// datapath control
logic store_axil_w_input_to_output;
logic store_axil_w_input_to_temp;
logic store_axil_w_temp_to_output;
assign s_axil_wr.wready = s_axil_wready_reg;
assign m_axil_wr.wdata = m_axil_wdata_reg;
assign m_axil_wr.wstrb = m_axil_wstrb_reg;
assign m_axil_wr.wuser = WUSER_EN ? m_axil_wuser_reg : '0;
assign m_axil_wr.wvalid = m_axil_wvalid_reg;
// enable ready input next cycle if output is ready or the temp reg will not be filled on the next cycle (output reg empty or no input)
wire s_axil_wready_early = m_axil_wr.wready || (!temp_m_axil_wvalid_reg && (!m_axil_wvalid_reg || !s_axil_wr.wvalid));
always_comb begin
// transfer sink ready state to source
m_axil_wvalid_next = m_axil_wvalid_reg;
temp_m_axil_wvalid_next = temp_m_axil_wvalid_reg;
store_axil_w_input_to_output = 1'b0;
store_axil_w_input_to_temp = 1'b0;
store_axil_w_temp_to_output = 1'b0;
if (s_axil_wready_reg) begin
// input is ready
if (m_axil_wr.wready || !m_axil_wvalid_reg) begin
// output is ready or currently not valid, transfer data to output
m_axil_wvalid_next = s_axil_wr.wvalid;
store_axil_w_input_to_output = 1'b1;
end else begin
// output is not ready, store input in temp
temp_m_axil_wvalid_next = s_axil_wr.wvalid;
store_axil_w_input_to_temp = 1'b1;
end
end else if (m_axil_wr.wready) begin
// input is not ready, but output is ready
m_axil_wvalid_next = temp_m_axil_wvalid_reg;
temp_m_axil_wvalid_next = 1'b0;
store_axil_w_temp_to_output = 1'b1;
end
end
always_ff @(posedge clk) begin
s_axil_wready_reg <= s_axil_wready_early;
m_axil_wvalid_reg <= m_axil_wvalid_next;
temp_m_axil_wvalid_reg <= temp_m_axil_wvalid_next;
// datapath
if (store_axil_w_input_to_output) begin
m_axil_wdata_reg <= s_axil_wr.wdata;
m_axil_wstrb_reg <= s_axil_wr.wstrb;
m_axil_wuser_reg <= s_axil_wr.wuser;
end else if (store_axil_w_temp_to_output) begin
m_axil_wdata_reg <= temp_m_axil_wdata_reg;
m_axil_wstrb_reg <= temp_m_axil_wstrb_reg;
m_axil_wuser_reg <= temp_m_axil_wuser_reg;
end
if (store_axil_w_input_to_temp) begin
temp_m_axil_wdata_reg <= s_axil_wr.wdata;
temp_m_axil_wstrb_reg <= s_axil_wr.wstrb;
temp_m_axil_wuser_reg <= s_axil_wr.wuser;
end
if (rst) begin
s_axil_wready_reg <= 1'b0;
m_axil_wvalid_reg <= 1'b0;
temp_m_axil_wvalid_reg <= 1'b0;
end
end
end else if (W_REG_TYPE == 1) begin
// simple register, inserts bubble cycles
// datapath registers
logic s_axil_wready_reg = 1'b0;
logic [DATA_W-1:0] m_axil_wdata_reg = '0;
logic [STRB_W-1:0] m_axil_wstrb_reg = '0;
logic [WUSER_W-1:0] m_axil_wuser_reg = '0;
logic m_axil_wvalid_reg = 1'b0, m_axil_wvalid_next;
// datapath control
logic store_axil_w_input_to_output;
assign s_axil_wr.wready = s_axil_wready_reg;
assign m_axil_wr.wdata = m_axil_wdata_reg;
assign m_axil_wr.wstrb = m_axil_wstrb_reg;
assign m_axil_wr.wuser = WUSER_EN ? m_axil_wuser_reg : '0;
assign m_axil_wr.wvalid = m_axil_wvalid_reg;
// enable ready input next cycle if output buffer will be empty
wire s_axil_wready_early = !m_axil_wvalid_next;
always_comb begin
// transfer sink ready state to source
m_axil_wvalid_next = m_axil_wvalid_reg;
store_axil_w_input_to_output = 1'b0;
if (s_axil_wready_reg) begin
m_axil_wvalid_next = s_axil_wr.wvalid;
store_axil_w_input_to_output = 1'b1;
end else if (m_axil_wr.wready) begin
m_axil_wvalid_next = 1'b0;
end
end
always_ff @(posedge clk) begin
s_axil_wready_reg <= s_axil_wready_early;
m_axil_wvalid_reg <= m_axil_wvalid_next;
// datapath
if (store_axil_w_input_to_output) begin
m_axil_wdata_reg <= s_axil_wr.wdata;
m_axil_wstrb_reg <= s_axil_wr.wstrb;
m_axil_wuser_reg <= s_axil_wr.wuser;
end
if (rst) begin
s_axil_wready_reg <= 1'b0;
m_axil_wvalid_reg <= 1'b0;
end
end
end else begin
// bypass W channel
assign m_axil_wr.wdata = s_axil_wr.wdata;
assign m_axil_wr.wstrb = s_axil_wr.wstrb;
assign m_axil_wr.wuser = WUSER_EN ? s_axil_wr.wuser : '0;
assign m_axil_wr.wvalid = s_axil_wr.wvalid;
assign s_axil_wr.wready = m_axil_wr.wready;
end
// B channel
if (B_REG_TYPE > 1) begin
// skid buffer, no bubble cycles
// datapath registers
logic m_axil_bready_reg = 1'b0;
logic [1:0] s_axil_bresp_reg = 2'b0;
logic [BUSER_W-1:0] s_axil_buser_reg = '0;
logic s_axil_bvalid_reg = 1'b0, s_axil_bvalid_next;
logic [1:0] temp_s_axil_bresp_reg = 2'b0;
logic [BUSER_W-1:0] temp_s_axil_buser_reg = '0;
logic temp_s_axil_bvalid_reg = 1'b0, temp_s_axil_bvalid_next;
// datapath control
logic store_axil_b_input_to_output;
logic store_axil_b_input_to_temp;
logic store_axil_b_temp_to_output;
assign m_axil_wr.bready = m_axil_bready_reg;
assign s_axil_wr.bresp = s_axil_bresp_reg;
assign s_axil_wr.buser = BUSER_EN ? s_axil_buser_reg : '0;
assign s_axil_wr.bvalid = s_axil_bvalid_reg;
// enable ready input next cycle if output is ready or the temp reg will not be filled on the next cycle (output reg empty or no input)
wire m_axil_bready_early = s_axil_wr.bready || (!temp_s_axil_bvalid_reg && (!s_axil_bvalid_reg || !m_axil_wr.bvalid));
always_comb begin
// transfer sink ready state to source
s_axil_bvalid_next = s_axil_bvalid_reg;
temp_s_axil_bvalid_next = temp_s_axil_bvalid_reg;
store_axil_b_input_to_output = 1'b0;
store_axil_b_input_to_temp = 1'b0;
store_axil_b_temp_to_output = 1'b0;
if (m_axil_bready_reg) begin
// input is ready
if (s_axil_wr.bready || !s_axil_bvalid_reg) begin
// output is ready or currently not valid, transfer data to output
s_axil_bvalid_next = m_axil_wr.bvalid;
store_axil_b_input_to_output = 1'b1;
end else begin
// output is not ready, store input in temp
temp_s_axil_bvalid_next = m_axil_wr.bvalid;
store_axil_b_input_to_temp = 1'b1;
end
end else if (s_axil_wr.bready) begin
// input is not ready, but output is ready
s_axil_bvalid_next = temp_s_axil_bvalid_reg;
temp_s_axil_bvalid_next = 1'b0;
store_axil_b_temp_to_output = 1'b1;
end
end
always_ff @(posedge clk) begin
m_axil_bready_reg <= m_axil_bready_early;
s_axil_bvalid_reg <= s_axil_bvalid_next;
temp_s_axil_bvalid_reg <= temp_s_axil_bvalid_next;
// datapath
if (store_axil_b_input_to_output) begin
s_axil_bresp_reg <= m_axil_wr.bresp;
s_axil_buser_reg <= m_axil_wr.buser;
end else if (store_axil_b_temp_to_output) begin
s_axil_bresp_reg <= temp_s_axil_bresp_reg;
s_axil_buser_reg <= temp_s_axil_buser_reg;
end
if (store_axil_b_input_to_temp) begin
temp_s_axil_bresp_reg <= m_axil_wr.bresp;
temp_s_axil_buser_reg <= m_axil_wr.buser;
end
if (rst) begin
m_axil_bready_reg <= 1'b0;
s_axil_bvalid_reg <= 1'b0;
temp_s_axil_bvalid_reg <= 1'b0;
end
end
end else if (B_REG_TYPE == 1) begin
// simple register, inserts bubble cycles
// datapath registers
logic m_axil_bready_reg = 1'b0;
logic [1:0] s_axil_bresp_reg = 2'b0;
logic [BUSER_W-1:0] s_axil_buser_reg = '0;
logic s_axil_bvalid_reg = 1'b0, s_axil_bvalid_next;
// datapath control
logic store_axil_b_input_to_output;
assign m_axil_wr.bready = m_axil_bready_reg;
assign s_axil_wr.bresp = s_axil_bresp_reg;
assign s_axil_wr.buser = BUSER_EN ? s_axil_buser_reg : '0;
assign s_axil_wr.bvalid = s_axil_bvalid_reg;
// enable ready input next cycle if output buffer will be empty
wire m_axil_bready_early = !s_axil_bvalid_next;
always_comb begin
// transfer sink ready state to source
s_axil_bvalid_next = s_axil_bvalid_reg;
store_axil_b_input_to_output = 1'b0;
if (m_axil_bready_reg) begin
s_axil_bvalid_next = m_axil_wr.bvalid;
store_axil_b_input_to_output = 1'b1;
end else if (s_axil_wr.bready) begin
s_axil_bvalid_next = 1'b0;
end
end
always_ff @(posedge clk) begin
m_axil_bready_reg <= m_axil_bready_early;
s_axil_bvalid_reg <= s_axil_bvalid_next;
// datapath
if (store_axil_b_input_to_output) begin
s_axil_bresp_reg <= m_axil_wr.bresp;
s_axil_buser_reg <= m_axil_wr.buser;
end
if (rst) begin
m_axil_bready_reg <= 1'b0;
s_axil_bvalid_reg <= 1'b0;
end
end
end else begin
// bypass B channel
assign s_axil_wr.bresp = m_axil_wr.bresp;
assign s_axil_wr.buser = BUSER_EN ? m_axil_wr.buser : '0;
assign s_axil_wr.bvalid = m_axil_wr.bvalid;
assign m_axil_wr.bready = s_axil_wr.bready;
end
endmodule
`resetall