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util_axis_fifo: Refactoring 

Refactor the AXI4 stream FIFO implementation.

  - Define a single address generator which supports both single and double
clock mode. (synchronous and asynchronous)
  - Fix FIFO status bits (empty/full). NOTE: In asynchronous mode the
flags can have a several clock cycle delay in function of the upstream/downstream
clock ratio.
  - In synchronous none FIFO mode (ADDRESS_WIDTH==0), the module acts as
    an AXI4 stream pipeline.
main
Istvan Csomortani 2020-11-18 16:14:49 +00:00 committed by István Csomortáni
parent 5df2961624
commit 5ac728392d
7 changed files with 306 additions and 530 deletions
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5
library/util_axis_fifo/Makefile
View File

@ -6,9 +6,8 @@
LIBRARY_NAME := util_axis_fifo
GENERIC_DEPS += ../common/ad_mem.v
GENERIC_DEPS += address_gray.v
GENERIC_DEPS += address_gray_pipelined.v
GENERIC_DEPS += address_sync.v
GENERIC_DEPS += ../common/ad_mem_asym.v
GENERIC_DEPS += util_axis_fifo_address_generator.v
GENERIC_DEPS += util_axis_fifo.v
XILINX_DEPS += util_axis_fifo_ip.tcl

155
library/util_axis_fifo/address_gray.v
View File

@ -1,155 +0,0 @@
// ***************************************************************************
// ***************************************************************************
// Copyright 2014 - 2017 (c) Analog Devices, Inc. All rights reserved.
//
// In this HDL repository, there are many different and unique modules, consisting
// of various HDL (Verilog or VHDL) components. The individual modules are
// developed independently, and may be accompanied by separate and unique license
// terms.
//
// The user should read each of these license terms, and understand the
// freedoms and responsibilities that he or she has by using this source/core.
//
// This core is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
// A PARTICULAR PURPOSE.
//
// Redistribution and use of source or resulting binaries, with or without modification
// of this file, are permitted under one of the following two license terms:
//
// 1. The GNU General Public License version 2 as published by the
// Free Software Foundation, which can be found in the top level directory
// of this repository (LICENSE_GPL2), and also online at:
// <https://www.gnu.org/licenses/old-licenses/gpl-2.0.html>
//
// OR
//
// 2. An ADI specific BSD license, which can be found in the top level directory
// of this repository (LICENSE_ADIBSD), and also on-line at:
// https://github.com/analogdevicesinc/hdl/blob/master/LICENSE_ADIBSD
// This will allow to generate bit files and not release the source code,
// as long as it attaches to an ADI device.
//
// ***************************************************************************
// ***************************************************************************
`timescale 1ns/100ps
module fifo_address_gray #(
parameter ADDRESS_WIDTH = 4
) (
input m_axis_aclk,
input m_axis_aresetn,
input m_axis_ready,
output reg m_axis_valid,
output reg [ADDRESS_WIDTH:0] m_axis_level,
input s_axis_aclk,
input s_axis_aresetn,
output reg s_axis_ready,
input s_axis_valid,
output reg s_axis_empty,
output [ADDRESS_WIDTH-1:0] s_axis_waddr,
output reg [ADDRESS_WIDTH:0] s_axis_room
);
reg [ADDRESS_WIDTH:0] _s_axis_waddr = 'h00;
reg [ADDRESS_WIDTH:0] _s_axis_waddr_next;
reg [ADDRESS_WIDTH:0] _m_axis_raddr = 'h00;
reg [ADDRESS_WIDTH:0] _m_axis_raddr_next;
reg [ADDRESS_WIDTH:0] s_axis_waddr_gray = 'h00;
wire [ADDRESS_WIDTH:0] s_axis_waddr_gray_next;
wire [ADDRESS_WIDTH:0] s_axis_raddr_gray;
reg [ADDRESS_WIDTH:0] m_axis_raddr_gray = 'h00;
wire [ADDRESS_WIDTH:0] m_axis_raddr_gray_next;
wire [ADDRESS_WIDTH:0] m_axis_waddr_gray;
assign s_axis_waddr = _s_axis_waddr[ADDRESS_WIDTH-1:0];
always @(*)
begin
if (s_axis_ready && s_axis_valid)
_s_axis_waddr_next <= _s_axis_waddr + 1;
else
_s_axis_waddr_next <= _s_axis_waddr;
end
assign s_axis_waddr_gray_next = _s_axis_waddr_next ^ _s_axis_waddr_next[ADDRESS_WIDTH:1];
always @(posedge s_axis_aclk)
begin
if (s_axis_aresetn == 1'b0) begin
_s_axis_waddr <= 'h00;
s_axis_waddr_gray <= 'h00;
end else begin
_s_axis_waddr <= _s_axis_waddr_next;
s_axis_waddr_gray <= s_axis_waddr_gray_next;
end
end
always @(*)
begin
if (m_axis_ready && m_axis_valid)
_m_axis_raddr_next <= _m_axis_raddr + 1;
else
_m_axis_raddr_next <= _m_axis_raddr;
end
assign m_axis_raddr_gray_next = _m_axis_raddr_next ^ _m_axis_raddr_next[ADDRESS_WIDTH:1];
always @(posedge m_axis_aclk)
begin
if (m_axis_aresetn == 1'b0) begin
_m_axis_raddr <= 'h00;
m_axis_raddr_gray <= 'h00;
end else begin
_m_axis_raddr <= _m_axis_raddr_next;
m_axis_raddr_gray <= m_axis_raddr_gray_next;
end
end
sync_bits #(
.NUM_OF_BITS(ADDRESS_WIDTH + 1)
) i_waddr_sync (
.out_clk(m_axis_aclk),
.out_resetn(m_axis_aresetn),
.in_bits(s_axis_waddr_gray),
.out_bits(m_axis_waddr_gray)
);
sync_bits #(
.NUM_OF_BITS(ADDRESS_WIDTH + 1)
) i_raddr_sync (
.out_clk(s_axis_aclk),
.out_resetn(s_axis_aresetn),
.in_bits(m_axis_raddr_gray),
.out_bits(s_axis_raddr_gray)
);
always @(posedge s_axis_aclk)
begin
if (s_axis_aresetn == 1'b0) begin
s_axis_ready <= 1'b1;
s_axis_empty <= 1'b1;
end else begin
s_axis_ready <= (s_axis_raddr_gray[ADDRESS_WIDTH] == s_axis_waddr_gray_next[ADDRESS_WIDTH] ||
s_axis_raddr_gray[ADDRESS_WIDTH-1] == s_axis_waddr_gray_next[ADDRESS_WIDTH-1] ||
s_axis_raddr_gray[ADDRESS_WIDTH-2:0] != s_axis_waddr_gray_next[ADDRESS_WIDTH-2:0]);
s_axis_empty <= s_axis_raddr_gray == s_axis_waddr_gray_next;
end
end
always @(posedge m_axis_aclk)
begin
if (s_axis_aresetn == 1'b0)
m_axis_valid <= 1'b0;
else begin
m_axis_valid <= m_axis_waddr_gray != m_axis_raddr_gray_next;
end
end
endmodule

152
library/util_axis_fifo/address_gray_pipelined.v
View File

@ -1,152 +0,0 @@
// ***************************************************************************
// ***************************************************************************
// Copyright 2014 - 2017 (c) Analog Devices, Inc. All rights reserved.
//
// In this HDL repository, there are many different and unique modules, consisting
// of various HDL (Verilog or VHDL) components. The individual modules are
// developed independently, and may be accompanied by separate and unique license
// terms.
//
// The user should read each of these license terms, and understand the
// freedoms and responsibilities that he or she has by using this source/core.
//
// This core is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
// A PARTICULAR PURPOSE.
//
// Redistribution and use of source or resulting binaries, with or without modification
// of this file, are permitted under one of the following two license terms:
//
// 1. The GNU General Public License version 2 as published by the
// Free Software Foundation, which can be found in the top level directory
// of this repository (LICENSE_GPL2), and also online at:
// <https://www.gnu.org/licenses/old-licenses/gpl-2.0.html>
//
// OR
//
// 2. An ADI specific BSD license, which can be found in the top level directory
// of this repository (LICENSE_ADIBSD), and also on-line at:
// https://github.com/analogdevicesinc/hdl/blob/master/LICENSE_ADIBSD
// This will allow to generate bit files and not release the source code,
// as long as it attaches to an ADI device.
//
// ***************************************************************************
// ***************************************************************************
`timescale 1ns/100ps
module fifo_address_gray_pipelined #(
parameter ADDRESS_WIDTH = 4
) (
input m_axis_aclk,
input m_axis_aresetn,
input m_axis_ready,
output reg m_axis_valid,
output [ADDRESS_WIDTH-1:0] m_axis_raddr,
output reg [ADDRESS_WIDTH:0] m_axis_level,
input s_axis_aclk,
input s_axis_aresetn,
output reg s_axis_ready,
input s_axis_valid,
output reg s_axis_empty,
output [ADDRESS_WIDTH-1:0] s_axis_waddr,
output reg [ADDRESS_WIDTH:0] s_axis_room
);
localparam MAX_ROOM = {1'b1,{ADDRESS_WIDTH{1'b0}}};
reg [ADDRESS_WIDTH:0] _s_axis_waddr = 'h00;
reg [ADDRESS_WIDTH:0] _s_axis_waddr_next;
wire [ADDRESS_WIDTH:0] _s_axis_raddr;
reg [ADDRESS_WIDTH:0] _m_axis_raddr = 'h00;
reg [ADDRESS_WIDTH:0] _m_axis_raddr_next;
wire [ADDRESS_WIDTH:0] _m_axis_waddr;
assign s_axis_waddr = _s_axis_waddr[ADDRESS_WIDTH-1:0];
assign m_axis_raddr = _m_axis_raddr[ADDRESS_WIDTH-1:0];
always @(*)
begin
if (s_axis_ready && s_axis_valid)
_s_axis_waddr_next <= _s_axis_waddr + 1'b1;
else
_s_axis_waddr_next <= _s_axis_waddr;
end
always @(posedge s_axis_aclk)
begin
if (s_axis_aresetn == 1'b0) begin
_s_axis_waddr <= 'h00;
end else begin
_s_axis_waddr <= _s_axis_waddr_next;
end
end
always @(*)
begin
if (m_axis_ready && m_axis_valid)
_m_axis_raddr_next <= _m_axis_raddr + 1'b1;
else
_m_axis_raddr_next <= _m_axis_raddr;
end
always @(posedge m_axis_aclk)
begin
if (m_axis_aresetn == 1'b0) begin
_m_axis_raddr <= 'h00;
end else begin
_m_axis_raddr <= _m_axis_raddr_next;
end
end
sync_gray #(
.DATA_WIDTH(ADDRESS_WIDTH + 1)
) i_waddr_sync (
.in_clk(s_axis_aclk),
.in_resetn(s_axis_aresetn),
.out_clk(m_axis_aclk),
.out_resetn(m_axis_aresetn),
.in_count(_s_axis_waddr),
.out_count(_m_axis_waddr)
);
sync_gray #(
.DATA_WIDTH(ADDRESS_WIDTH + 1)
) i_raddr_sync (
.in_clk(m_axis_aclk),
.in_resetn(m_axis_aresetn),
.out_clk(s_axis_aclk),
.out_resetn(s_axis_aresetn),
.in_count(_m_axis_raddr),
.out_count(_s_axis_raddr)
);
always @(posedge s_axis_aclk)
begin
if (s_axis_aresetn == 1'b0) begin
s_axis_ready <= 1'b1;
s_axis_empty <= 1'b1;
s_axis_room <= MAX_ROOM;
end else begin
s_axis_ready <= (_s_axis_raddr[ADDRESS_WIDTH] == _s_axis_waddr_next[ADDRESS_WIDTH] ||
_s_axis_raddr[ADDRESS_WIDTH-1:0] != _s_axis_waddr_next[ADDRESS_WIDTH-1:0]);
s_axis_empty <= _s_axis_raddr == _s_axis_waddr_next;
s_axis_room <= _s_axis_raddr - _s_axis_waddr_next + MAX_ROOM;
end
end
always @(posedge m_axis_aclk)
begin
if (m_axis_aresetn == 1'b0) begin
m_axis_valid <= 1'b0;
m_axis_level <= 'h00;
end else begin
m_axis_valid <= _m_axis_waddr != _m_axis_raddr_next;
m_axis_level <= _m_axis_waddr - _m_axis_raddr_next;
end
end
endmodule

109
library/util_axis_fifo/address_sync.v
View File

@ -1,109 +0,0 @@
// ***************************************************************************
// ***************************************************************************
// Copyright 2014 - 2017 (c) Analog Devices, Inc. All rights reserved.
//
// In this HDL repository, there are many different and unique modules, consisting
// of various HDL (Verilog or VHDL) components. The individual modules are
// developed independently, and may be accompanied by separate and unique license
// terms.
//
// The user should read each of these license terms, and understand the
// freedoms and responsibilities that he or she has by using this source/core.
//
// This core is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
// A PARTICULAR PURPOSE.
//
// Redistribution and use of source or resulting binaries, with or without modification
// of this file, are permitted under one of the following two license terms:
//
// 1. The GNU General Public License version 2 as published by the
// Free Software Foundation, which can be found in the top level directory
// of this repository (LICENSE_GPL2), and also online at:
// <https://www.gnu.org/licenses/old-licenses/gpl-2.0.html>
//
// OR
//
// 2. An ADI specific BSD license, which can be found in the top level directory
// of this repository (LICENSE_ADIBSD), and also on-line at:
// https://github.com/analogdevicesinc/hdl/blob/master/LICENSE_ADIBSD
// This will allow to generate bit files and not release the source code,
// as long as it attaches to an ADI device.
//
// ***************************************************************************
// ***************************************************************************
`timescale 1ns/100ps
module fifo_address_sync #(
parameter ADDRESS_WIDTH = 4
) (
input clk,
input resetn,
input m_axis_ready,
output reg m_axis_valid,
output reg [ADDRESS_WIDTH-1:0] m_axis_raddr,
output [ADDRESS_WIDTH:0] m_axis_level,
output reg s_axis_ready,
input s_axis_valid,
output reg s_axis_empty,
output reg [ADDRESS_WIDTH-1:0] s_axis_waddr,
output [ADDRESS_WIDTH:0] s_axis_room
);
localparam MAX_ROOM = {1'b1,{ADDRESS_WIDTH{1'b0}}};
reg [ADDRESS_WIDTH:0] room = MAX_ROOM;
reg [ADDRESS_WIDTH:0] level = 'h00;
reg [ADDRESS_WIDTH:0] level_next;
assign s_axis_room = room;
assign m_axis_level = level;
wire read = m_axis_ready & m_axis_valid;
wire write = s_axis_ready & s_axis_valid;
always @(posedge clk)
begin
if (resetn == 1'b0) begin
s_axis_waddr <= 'h00;
m_axis_raddr <= 'h00;
end else begin
if (write)
s_axis_waddr <= s_axis_waddr + 1'b1;
if (read)
m_axis_raddr <= m_axis_raddr + 1'b1;
end
end
always @(*)
begin
if (read & ~write)
level_next <= level - 1'b1;
else if (~read & write)
level_next <= level + 1'b1;
else
level_next <= level;
end
always @(posedge clk)
begin
if (resetn == 1'b0) begin
m_axis_valid <= 1'b0;
s_axis_ready <= 1'b0;
level <= 'h00;
room <= MAX_ROOM;
s_axis_empty <= 'h00;
end else begin
level <= level_next;
room <= MAX_ROOM - level_next;
m_axis_valid <= level_next != 0;
s_axis_ready <= level_next != MAX_ROOM;
s_axis_empty <= level_next == 0;
end
end
endmodule

109
library/util_axis_fifo/util_axis_fifo.v
View File

@ -32,32 +32,34 @@
//
// ***************************************************************************
// ***************************************************************************
`timescale 1ns/100ps
`timescale 1ns/1ps
module util_axis_fifo #(
parameter DATA_WIDTH = 64,
parameter ADDRESS_WIDTH = 5,
parameter ASYNC_CLK = 1,
parameter ADDRESS_WIDTH = 4,
parameter S_AXIS_REGISTERED = 1
parameter M_AXIS_REGISTERED = 1
) (
input m_axis_aclk,
input m_axis_aresetn,
input m_axis_ready,
output m_axis_valid,
output [DATA_WIDTH-1:0] m_axis_data,
output [ADDRESS_WIDTH:0] m_axis_level,
output [ADDRESS_WIDTH-1:0] m_axis_level,
output m_axis_empty,
input s_axis_aclk,
input s_axis_aresetn,
output s_axis_ready,
input s_axis_valid,
input [DATA_WIDTH-1:0] s_axis_data,
output s_axis_empty,
output [ADDRESS_WIDTH:0] s_axis_room
output [ADDRESS_WIDTH-1:0] s_axis_room,
output s_axis_full
);
generate if (ADDRESS_WIDTH == 0) begin
generate if (ADDRESS_WIDTH == 0) begin : zerodeep /* it's not a real FIFO, just a 1 stage pipeline */
if (ASYNC_CLK) begin
reg [DATA_WIDTH-1:0] cdc_sync_fifo_ram;
reg s_axis_waddr = 1'b0;
@ -87,9 +89,9 @@ generate if (ADDRESS_WIDTH == 0) begin
);
assign m_axis_valid = m_axis_raddr != m_axis_waddr;
assign m_axis_level = m_axis_valid;
assign m_axis_level = ~m_axis_ready;
assign s_axis_ready = s_axis_raddr == s_axis_waddr;
assign s_axis_empty = s_axis_ready;
assign s_axis_empty = ~s_axis_valid;
assign s_axis_room = s_axis_ready;
always @(posedge s_axis_aclk) begin
@ -100,12 +102,10 @@ generate if (ADDRESS_WIDTH == 0) begin
always @(posedge s_axis_aclk) begin
if (s_axis_aresetn == 1'b0) begin
s_axis_waddr <= 1'b0;
end else begin
if (s_axis_ready & s_axis_valid) begin
end else if (s_axis_ready & s_axis_valid) begin
s_axis_waddr <= s_axis_waddr + 1'b1;
end
end
end
always @(posedge m_axis_aclk) begin
if (m_axis_aresetn == 1'b0) begin
@ -118,21 +118,46 @@ generate if (ADDRESS_WIDTH == 0) begin
assign m_axis_data = cdc_sync_fifo_ram;
end else begin
end else begin /* !ASYNC_CLK */
reg [DATA_WIDTH-1:0] ram[0:2**ADDRESS_WIDTH-1];
// Note: In this mode, the write and read interface must have a symmetric
// aspect ratio
reg [DATA_WIDTH-1:0] axis_data_d;
reg axis_valid_d;
always @(posedge s_axis_aclk) begin
if (!s_axis_aresetn) begin
axis_data_d <= {DATA_WIDTH{1'b0}};
axis_valid_d <= 1'b0;
end else if (s_axis_ready) begin
axis_data_d <= s_axis_data;
axis_valid_d <= s_axis_valid;
end
end
assign m_axis_data = axis_data_d;
assign m_axis_valid = axis_valid_d;
assign s_axis_ready = m_axis_ready | ~m_axis_valid;
assign m_axis_empty = 1'b0;
assign m_axis_level = 1'b0;
assign s_axis_full = 1'b0;
assign s_axis_room = 1'b0;
end
end else begin : fifo /* ADDRESS_WIDTH != 0 - this is a real FIFO implementation */
wire [ADDRESS_WIDTH-1:0] s_axis_waddr;
wire [ADDRESS_WIDTH-1:0] m_axis_raddr;
wire _m_axis_ready;
wire _m_axis_valid;
wire [ADDRESS_WIDTH:0] _m_axis_level;
wire s_mem_write;
wire m_mem_read;
reg valid;
reg valid = 1'b0;
/* Control for first falls through */
always @(posedge m_axis_aclk) begin
if (m_axis_aresetn == 1'b0) begin
valid <= 1'b0;
@ -147,29 +172,29 @@ end else begin
assign s_mem_write = s_axis_ready & s_axis_valid;
assign m_mem_read = (~valid || m_axis_ready) && _m_axis_valid;
if (ASYNC_CLK == 1) begin
// The assumption is that in this mode the S_AXIS_REGISTERED is 1
fifo_address_gray_pipelined #(
.ADDRESS_WIDTH(ADDRESS_WIDTH)
) i_address_gray (
util_axis_fifo_address_generator #(
.ASYNC_CLK(ASYNC_CLK),
.ADDRESS_WIDTH(ADDRESS_WIDTH))
i_address_gray (
.m_axis_aclk(m_axis_aclk),
.m_axis_aresetn(m_axis_aresetn),
.m_axis_ready(_m_axis_ready),
.m_axis_valid(_m_axis_valid),
.m_axis_raddr(m_axis_raddr),
.m_axis_level(_m_axis_level),
.m_axis_level(m_axis_level),
.m_axis_empty(m_axis_empty),
.s_axis_aclk(s_axis_aclk),
.s_axis_aresetn(s_axis_aresetn),
.s_axis_ready(s_axis_ready),
.s_axis_valid(s_axis_valid),
.s_axis_empty(s_axis_empty),
.s_axis_full(s_axis_full),
.s_axis_waddr(s_axis_waddr),
.s_axis_room(s_axis_room)
);
if (ASYNC_CLK == 1) begin : async_clocks /* Asynchronous WRITE/READ clocks */
// The assumption is that in this mode the M_AXIS_REGISTERED is 1
// When the clocks are asynchronous instantiate a block RAM
// regardless of the requested size to make sure we threat the
// clock crossing correctly
@ -189,29 +214,10 @@ end else begin
assign _m_axis_ready = ~valid || m_axis_ready;
assign m_axis_valid = valid;
// the util_axis_fifo is functioning in 'first write fall through' mode,
// which means that we need to assure that the value of the level reflects
// the actual FIFO level plus the available data, which sits on the bus
assign m_axis_level = (m_axis_valid) ? _m_axis_level + 1'b1 : _m_axis_level;
end else begin
end else begin : sync_clocks /* Synchronous WRITE/READ clocks */
fifo_address_sync #(
.ADDRESS_WIDTH(ADDRESS_WIDTH)
) i_address_sync (
.clk(m_axis_aclk),
.resetn(m_axis_aresetn),
.m_axis_ready(_m_axis_ready),
.m_axis_valid(_m_axis_valid),
.m_axis_raddr(m_axis_raddr),
.m_axis_level(m_axis_level),
.s_axis_ready(s_axis_ready),
.s_axis_valid(s_axis_valid),
.s_axis_empty(s_axis_empty),
.s_axis_waddr(s_axis_waddr),
.s_axis_room(s_axis_room)
);
reg [DATA_WIDTH-1:0] ram[0:2**ADDRESS_WIDTH-1];
// When the clocks are synchronous use behavioral modeling for the SDP RAM
// Let the synthesizer decide what to infer (distributed or block RAM)
@ -220,7 +226,7 @@ end else begin
ram[s_axis_waddr] <= s_axis_data;
end
if (S_AXIS_REGISTERED == 1) begin
if (M_AXIS_REGISTERED == 1) begin
reg [DATA_WIDTH-1:0] data;
@ -240,9 +246,8 @@ end else begin
assign m_axis_data = ram[m_axis_raddr];
end
end
end endgenerate
end /* fifo */
endgenerate
endmodule

187
library/util_axis_fifo/util_axis_fifo_address_generator.v Normal file
View File

@ -0,0 +1,187 @@
// ***************************************************************************
// ***************************************************************************
// Copyright 2014 - 2017 (c) Analog Devices, Inc. All rights reserved.
//
// In this HDL repository, there are many different and unique modules, consisting
// of various HDL (Verilog or VHDL) components. The individual modules are
// developed independently, and may be accompanied by separate and unique license
// terms.
//
// The user should read each of these license terms, and understand the
// freedoms and responsibilities that he or she has by using this source/core.
//
// This core is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
// A PARTICULAR PURPOSE.
//
// Redistribution and use of source or resulting binaries, with or without modification
// of this file, are permitted under one of the following two license terms:
//
// 1. The GNU General Public License version 2 as published by the
// Free Software Foundation, which can be found in the top level directory
// of this repository (LICENSE_GPL2), and also online at:
// <https://www.gnu.org/licenses/old-licenses/gpl-2.0.html>
//
// OR
//
// 2. An ADI specific BSD license, which can be found in the top level directory
// of this repository (LICENSE_ADIBSD), and also on-line at:
// https://github.com/analogdevicesinc/hdl/blob/master/LICENSE_ADIBSD
// This will allow to generate bit files and not release the source code,
// as long as it attaches to an ADI device.
//
// ***************************************************************************
// ***************************************************************************
`timescale 1ns/1ps
module util_axis_fifo_address_generator #(
parameter ASYNC_CLK = 0, // single or double clocked FIFO
parameter ADDRESS_WIDTH = 4 // address width, effective FIFO depth
) (
// Read interface - Sink side
input m_axis_aclk,
input m_axis_aresetn,
input m_axis_ready,
output m_axis_valid,
output m_axis_empty,
output [ADDRESS_WIDTH-1:0] m_axis_raddr,
output [ADDRESS_WIDTH-1:0] m_axis_level,
// Write interface - Source side
input s_axis_aclk,
input s_axis_aresetn,
output s_axis_ready,
input s_axis_valid,
output s_axis_full,
output [ADDRESS_WIDTH-1:0] s_axis_waddr,
output [ADDRESS_WIDTH-1:0] s_axis_room
);
//------------------------------------------------------------------------------
// local parameters
//------------------------------------------------------------------------------
localparam FIFO_DEPTH = {ADDRESS_WIDTH{1'b1}};
//------------------------------------------------------------------------------
// registers
//------------------------------------------------------------------------------
// Definition of address counters
// All the counters are wider with one bit to indicate wraparounds
reg [ADDRESS_WIDTH:0] s_axis_waddr_reg = 'h0;
reg [ADDRESS_WIDTH:0] m_axis_raddr_reg = 'h0;
//------------------------------------------------------------------------------
// wires
//------------------------------------------------------------------------------
wire [ADDRESS_WIDTH:0] s_axis_raddr_reg;
wire [ADDRESS_WIDTH:0] m_axis_waddr_reg;
wire s_axis_write_s;
wire s_axis_ready_s;
wire m_axis_read_s;
wire m_axis_valid_s;
wire [ADDRESS_WIDTH-1:0] m_axis_level_s;
//------------------------------------------------------------------------------
// Write address counter
//------------------------------------------------------------------------------
assign s_axis_write_s = s_axis_ready && s_axis_valid;
always @(posedge s_axis_aclk)
begin
if (!s_axis_aresetn)
s_axis_waddr_reg <= 'h0;
else
if (s_axis_write_s)
s_axis_waddr_reg <= s_axis_waddr_reg + 1'b1;
end
//------------------------------------------------------------------------------
// Read address counter
//------------------------------------------------------------------------------
assign m_axis_read_s = m_axis_ready && m_axis_valid;
always @(posedge m_axis_aclk)
begin
if (!m_axis_aresetn)
m_axis_raddr_reg <= 'h0;
else
if (m_axis_read_s)
m_axis_raddr_reg <= m_axis_raddr_reg + 1'b1;
end
//------------------------------------------------------------------------------
// Output assignments
//------------------------------------------------------------------------------
assign s_axis_waddr = s_axis_waddr_reg[ADDRESS_WIDTH-1:0];
assign m_axis_raddr = m_axis_raddr_reg[ADDRESS_WIDTH-1:0];
//------------------------------------------------------------------------------
// CDC circuits for double clock configuration
//------------------------------------------------------------------------------
generate if (ASYNC_CLK == 1) begin : g_async_clock
// CDC transfer of the write pointer to the read clock domain
sync_gray #(
.DATA_WIDTH(ADDRESS_WIDTH + 1)
) i_waddr_sync_gray (
.in_clk(s_axis_aclk),
.in_resetn(s_axis_aresetn),
.out_clk(m_axis_aclk),
.out_resetn(m_axis_aresetn),
.in_count(s_axis_waddr_reg),
.out_count(m_axis_waddr_reg)
);
// CDC transfer of the read pointer to the write clock domain
sync_gray #(
.DATA_WIDTH(ADDRESS_WIDTH + 1)
) i_raddr_sync_gray (
.in_clk(m_axis_aclk),
.in_resetn(m_axis_aresetn),
.out_clk(s_axis_aclk),
.out_resetn(s_axis_aresetn),
.in_count(m_axis_raddr_reg),
.out_count(s_axis_raddr_reg)
);
end else begin
assign m_axis_waddr_reg = s_axis_waddr_reg;
assign s_axis_raddr_reg = m_axis_raddr_reg;
end
endgenerate
//------------------------------------------------------------------------------
// FIFO write logic - upstream
//
// s_axis_full - FIFO is full if next write pointer equal to read pointer
// s_axis_ready - FIFO is always ready, unless it's full
//
//------------------------------------------------------------------------------
wire [ADDRESS_WIDTH:0] s_axis_fifo_fill = s_axis_waddr_reg - s_axis_raddr_reg;
assign s_axis_full = (s_axis_fifo_fill == { 1'b1, {ADDRESS_WIDTH-1{1'b0}}});
assign s_axis_ready = ~s_axis_full;
assign s_axis_room = ~s_axis_fifo_fill;
//------------------------------------------------------------------------------
// FIFO read logic - downstream
//
// m_axis_empty - FIFO is empty if read pointer equal to write pointer
// m_axis_valid - FIFO has a valid output data, if it's not empty
//
//------------------------------------------------------------------------------
wire [ADDRESS_WIDTH:0] m_axis_fifo_fill = m_axis_waddr_reg - m_axis_raddr_reg;
assign m_axis_empty = m_axis_fifo_fill == 0;
assign m_axis_valid = ~m_axis_empty;
assign m_axis_level = m_axis_fifo_fill;
endmodule

7
library/util_axis_fifo/util_axis_fifo_ip.tcl
View File

@ -4,10 +4,9 @@ source $ad_hdl_dir/library/scripts/adi_ip_xilinx.tcl
adi_ip_create util_axis_fifo
adi_ip_files util_axis_fifo [list \
"address_gray.v" \
"address_gray_pipelined.v" \
"address_sync.v" \
"util_axis_fifo_address_generator.v" \
"../common/ad_mem.v" \
"../common/ad_mem_asym.v" \
"util_axis_fifo.v" \
]
@ -38,4 +37,6 @@ adi_add_bus "m_axis" "master" \
adi_add_bus_clock "m_axis_aclk" "m_axis" "m_axis_aresetn"
adi_add_bus_clock "s_axis_aclk" "s_axis" "m_axis_aresetn"
## TODO: Validate RD_ADDRESS_WIDTH
ipx::save_core [ipx::current_core]