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corundum/rtl/axis_frame_join.v
2018-10-25 10:20:17 -07:00

324 lines
11 KiB
Verilog

/*
Copyright (c) 2014-2018 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
`timescale 1ns / 1ps
/*
* AXI4-Stream frame joiner
*/
module axis_frame_join #
(
parameter S_COUNT = 4,
parameter DATA_WIDTH = 8,
parameter TAG_ENABLE = 1,
parameter TAG_WIDTH = 16
)
(
input wire clk,
input wire rst,
/*
* AXI inputs
*/
input wire [S_COUNT*DATA_WIDTH-1:0] s_axis_tdata,
input wire [S_COUNT-1:0] s_axis_tvalid,
output wire [S_COUNT-1:0] s_axis_tready,
input wire [S_COUNT-1:0] s_axis_tlast,
input wire [S_COUNT-1:0] s_axis_tuser,
/*
* AXI output
*/
output wire [DATA_WIDTH-1:0] m_axis_tdata,
output wire m_axis_tvalid,
input wire m_axis_tready,
output wire m_axis_tlast,
output wire m_axis_tuser,
/*
* Configuration
*/
input wire [TAG_WIDTH-1:0] tag,
/*
* Status signals
*/
output wire busy
);
parameter CL_S_COUNT = $clog2(S_COUNT);
parameter TAG_WORD_WIDTH = (TAG_WIDTH + DATA_WIDTH - 1) / DATA_WIDTH;
parameter CL_TAG_WORD_WIDTH = $clog2(TAG_WORD_WIDTH);
// state register
localparam [1:0]
STATE_IDLE = 2'd0,
STATE_WRITE_TAG = 2'd1,
STATE_TRANSFER = 2'd2;
reg [1:0] state_reg = STATE_IDLE, state_next;
reg [CL_TAG_WORD_WIDTH-1:0] frame_ptr_reg = {CL_TAG_WORD_WIDTH{1'b0}}, frame_ptr_next;
reg [CL_S_COUNT-1:0] port_sel_reg = {CL_S_COUNT{1'b0}}, port_sel_next;
reg busy_reg = 1'b0, busy_next;
reg output_tuser_reg = 1'b0, output_tuser_next;
reg [S_COUNT-1:0] s_axis_tready_reg = {S_COUNT{1'b0}}, s_axis_tready_next;
// internal datapath
reg [DATA_WIDTH-1:0] m_axis_tdata_int;
reg m_axis_tvalid_int;
reg m_axis_tready_int_reg = 1'b0;
reg m_axis_tlast_int;
reg m_axis_tuser_int;
wire m_axis_tready_int_early;
assign s_axis_tready = s_axis_tready_reg;
assign busy = busy_reg;
wire [DATA_WIDTH-1:0] input_tdata = s_axis_tdata[port_sel_reg*DATA_WIDTH +: DATA_WIDTH];
wire input_tvalid = s_axis_tvalid[port_sel_reg];
wire input_tlast = s_axis_tlast[port_sel_reg];
wire input_tuser = s_axis_tuser[port_sel_reg];
always @* begin
state_next = STATE_IDLE;
frame_ptr_next = frame_ptr_reg;
port_sel_next = port_sel_reg;
s_axis_tready_next = {S_COUNT{1'b0}};
m_axis_tdata_int = 8'd0;
m_axis_tvalid_int = 1'b0;
m_axis_tlast_int = 1'b0;
m_axis_tuser_int = 1'b0;
output_tuser_next = output_tuser_reg;
case (state_reg)
STATE_IDLE: begin
// idle state - wait for data
frame_ptr_next = {CL_TAG_WORD_WIDTH{1'b0}};
port_sel_next = {CL_S_COUNT{1'b0}};
output_tuser_next = 1'b0;
if (TAG_ENABLE) begin
// next cycle if started will send tag, so do not enable input
s_axis_tready_next = 1'b0;
end else begin
// next cycle if started will send data, so enable input
s_axis_tready_next = m_axis_tready_int_early;
end
if (s_axis_tvalid) begin
// input 0 valid; start transferring data
if (TAG_ENABLE) begin
// tag enabled, so transmit it
if (m_axis_tready_int_reg) begin
// output is ready, so short-circuit first tag word
frame_ptr_next = 1;
m_axis_tdata_int = tag;
m_axis_tvalid_int = 1'b1;
end
state_next = STATE_WRITE_TAG;
end else begin
// tag disabled, so transmit data
if (m_axis_tready_int_reg) begin
// output is ready, so short-circuit first data word
m_axis_tdata_int = s_axis_tdata;
m_axis_tvalid_int = 1'b1;
end
state_next = STATE_TRANSFER;
end
end else begin
state_next = STATE_IDLE;
end
end
STATE_WRITE_TAG: begin
// write tag data
if (m_axis_tready_int_reg) begin
// output ready, so send tag word
state_next = STATE_WRITE_TAG;
frame_ptr_next = frame_ptr_reg + 1;
m_axis_tvalid_int = 1'b1;
m_axis_tdata_int = tag >> frame_ptr_reg*DATA_WIDTH;
if (frame_ptr_reg == TAG_WORD_WIDTH-1) begin
s_axis_tready_next = m_axis_tready_int_early << 0;
state_next = STATE_TRANSFER;
end
end else begin
state_next = STATE_WRITE_TAG;
end
end
STATE_TRANSFER: begin
// transfer input data
// set ready for current input
s_axis_tready_next = m_axis_tready_int_early << port_sel_reg;
if (input_tvalid && m_axis_tready_int_reg) begin
// output ready, transfer byte
state_next = STATE_TRANSFER;
m_axis_tdata_int = input_tdata;
m_axis_tvalid_int = input_tvalid;
if (input_tlast) begin
// last flag received, switch to next port
port_sel_next = port_sel_reg + 1;
// save tuser - assert tuser out if ANY tuser asserts received
output_tuser_next = output_tuser_next | input_tuser;
// disable input
s_axis_tready_next = {S_COUNT{1'b0}};
if (S_COUNT == 1 || port_sel_reg == S_COUNT-1) begin
// last port - send tlast and tuser and revert to idle
m_axis_tlast_int = 1'b1;
m_axis_tuser_int = output_tuser_next;
state_next = STATE_IDLE;
end else begin
// otherwise, disable enable next port
s_axis_tready_next = m_axis_tready_int_early << port_sel_next;
end
end
end else begin
state_next = STATE_TRANSFER;
end
end
endcase
end
always @(posedge clk) begin
if (rst) begin
state_reg <= STATE_IDLE;
frame_ptr_reg <= {CL_TAG_WORD_WIDTH{1'b0}};
port_sel_reg <= {CL_S_COUNT{1'b0}};
s_axis_tready_reg <= {S_COUNT{1'b0}};
output_tuser_reg <= 1'b0;
busy_reg <= 1'b0;
end else begin
state_reg <= state_next;
frame_ptr_reg <= frame_ptr_next;
port_sel_reg <= port_sel_next;
s_axis_tready_reg <= s_axis_tready_next;
output_tuser_reg <= output_tuser_next;
busy_reg <= state_next != STATE_IDLE;
end
end
// output datapath logic
reg [DATA_WIDTH-1:0] m_axis_tdata_reg = {DATA_WIDTH{1'b0}};
reg m_axis_tvalid_reg = 1'b0, m_axis_tvalid_next;
reg m_axis_tlast_reg = 1'b0;
reg m_axis_tuser_reg = 1'b0;
reg [DATA_WIDTH-1:0] temp_m_axis_tdata_reg = {DATA_WIDTH{1'b0}};
reg temp_m_axis_tvalid_reg = 1'b0, temp_m_axis_tvalid_next;
reg temp_m_axis_tlast_reg = 1'b0;
reg temp_m_axis_tuser_reg = 1'b0;
// datapath control
reg store_axis_int_to_output;
reg store_axis_int_to_temp;
reg store_axis_temp_to_output;
assign m_axis_tdata = m_axis_tdata_reg;
assign m_axis_tvalid = m_axis_tvalid_reg;
assign m_axis_tlast = m_axis_tlast_reg;
assign m_axis_tuser = m_axis_tuser_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)
assign m_axis_tready_int_early = m_axis_tready || (!temp_m_axis_tvalid_reg && (!m_axis_tvalid_reg || !m_axis_tvalid_int));
always @* begin
// transfer sink ready state to source
m_axis_tvalid_next = m_axis_tvalid_reg;
temp_m_axis_tvalid_next = temp_m_axis_tvalid_reg;
store_axis_int_to_output = 1'b0;
store_axis_int_to_temp = 1'b0;
store_axis_temp_to_output = 1'b0;
if (m_axis_tready_int_reg) begin
// input is ready
if (m_axis_tready || !m_axis_tvalid_reg) begin
// output is ready or currently not valid, transfer data to output
m_axis_tvalid_next = m_axis_tvalid_int;
store_axis_int_to_output = 1'b1;
end else begin
// output is not ready, store input in temp
temp_m_axis_tvalid_next = m_axis_tvalid_int;
store_axis_int_to_temp = 1'b1;
end
end else if (m_axis_tready) begin
// input is not ready, but output is ready
m_axis_tvalid_next = temp_m_axis_tvalid_reg;
temp_m_axis_tvalid_next = 1'b0;
store_axis_temp_to_output = 1'b1;
end
end
always @(posedge clk) begin
if (rst) begin
m_axis_tvalid_reg <= 1'b0;
m_axis_tready_int_reg <= 1'b0;
temp_m_axis_tvalid_reg <= 1'b0;
end else begin
m_axis_tvalid_reg <= m_axis_tvalid_next;
m_axis_tready_int_reg <= m_axis_tready_int_early;
temp_m_axis_tvalid_reg <= temp_m_axis_tvalid_next;
end
// datapath
if (store_axis_int_to_output) begin
m_axis_tdata_reg <= m_axis_tdata_int;
m_axis_tlast_reg <= m_axis_tlast_int;
m_axis_tuser_reg <= m_axis_tuser_int;
end else if (store_axis_temp_to_output) begin
m_axis_tdata_reg <= temp_m_axis_tdata_reg;
m_axis_tlast_reg <= temp_m_axis_tlast_reg;
m_axis_tuser_reg <= temp_m_axis_tuser_reg;
end
if (store_axis_int_to_temp) begin
temp_m_axis_tdata_reg <= m_axis_tdata_int;
temp_m_axis_tlast_reg <= m_axis_tlast_int;
temp_m_axis_tuser_reg <= m_axis_tuser_int;
end
end
endmodule