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corundum/rtl/ip_eth_tx_64.v
Alex Forencich eb1f38a749 More critical path optimizations
2019-06-19 15:06:55 -07:00

649 lines
26 KiB
Verilog
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/*
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
/*
* IP ethernet frame transmitter (IP frame in, Ethernet frame out, 64 bit datapath)
*/
module ip_eth_tx_64
(
input wire clk,
input wire rst,
/*
* IP frame input
*/
input wire s_ip_hdr_valid,
output wire s_ip_hdr_ready,
input wire [47:0] s_eth_dest_mac,
input wire [47:0] s_eth_src_mac,
input wire [15:0] s_eth_type,
input wire [5:0] s_ip_dscp,
input wire [1:0] s_ip_ecn,
input wire [15:0] s_ip_length,
input wire [15:0] s_ip_identification,
input wire [2:0] s_ip_flags,
input wire [12:0] s_ip_fragment_offset,
input wire [7:0] s_ip_ttl,
input wire [7:0] s_ip_protocol,
input wire [31:0] s_ip_source_ip,
input wire [31:0] s_ip_dest_ip,
input wire [63:0] s_ip_payload_axis_tdata,
input wire [7:0] s_ip_payload_axis_tkeep,
input wire s_ip_payload_axis_tvalid,
output wire s_ip_payload_axis_tready,
input wire s_ip_payload_axis_tlast,
input wire s_ip_payload_axis_tuser,
/*
* Ethernet frame output
*/
output wire m_eth_hdr_valid,
input wire m_eth_hdr_ready,
output wire [47:0] m_eth_dest_mac,
output wire [47:0] m_eth_src_mac,
output wire [15:0] m_eth_type,
output wire [63:0] m_eth_payload_axis_tdata,
output wire [7:0] m_eth_payload_axis_tkeep,
output wire m_eth_payload_axis_tvalid,
input wire m_eth_payload_axis_tready,
output wire m_eth_payload_axis_tlast,
output wire m_eth_payload_axis_tuser,
/*
* Status signals
*/
output wire busy,
output wire error_payload_early_termination
);
/*
IP Frame
Field Length
Destination MAC address 6 octets
Source MAC address 6 octets
Ethertype (0x0800) 2 octets
Version (4) 4 bits
IHL (5-15) 4 bits
DSCP (0) 6 bits
ECN (0) 2 bits
length 2 octets
identification (0?) 2 octets
flags (010) 3 bits
fragment offset (0) 13 bits
time to live (64?) 1 octet
protocol 1 octet
header checksum 2 octets
source IP 4 octets
destination IP 4 octets
options (IHL-5)*4 octets
payload length octets
This module receives an IP frame with header fields in parallel along with the
payload in an AXI stream, combines the header with the payload, passes through
the Ethernet headers, and transmits the complete Ethernet payload on an AXI
interface.
*/
localparam [2:0]
STATE_IDLE = 3'd0,
STATE_WRITE_HEADER = 3'd1,
STATE_WRITE_HEADER_LAST = 3'd2,
STATE_WRITE_PAYLOAD = 3'd3,
STATE_WRITE_PAYLOAD_LAST = 3'd4,
STATE_WAIT_LAST = 3'd5;
reg [2:0] state_reg = STATE_IDLE, state_next;
// datapath control signals
reg store_ip_hdr;
reg store_last_word;
reg [5:0] hdr_ptr_reg = 6'd0, hdr_ptr_next;
reg [15:0] word_count_reg = 16'd0, word_count_next;
reg flush_save;
reg transfer_in_save;
reg [19:0] hdr_sum_temp;
reg [19:0] hdr_sum_reg = 20'd0, hdr_sum_next;
reg [63:0] last_word_data_reg = 64'd0;
reg [7:0] last_word_keep_reg = 8'd0;
reg [5:0] ip_dscp_reg = 6'd0;
reg [1:0] ip_ecn_reg = 2'd0;
reg [15:0] ip_length_reg = 16'd0;
reg [15:0] ip_identification_reg = 16'd0;
reg [2:0] ip_flags_reg = 3'd0;
reg [12:0] ip_fragment_offset_reg = 13'd0;
reg [7:0] ip_ttl_reg = 8'd0;
reg [7:0] ip_protocol_reg = 8'd0;
reg [31:0] ip_source_ip_reg = 32'd0;
reg [31:0] ip_dest_ip_reg = 32'd0;
reg s_ip_hdr_ready_reg = 1'b0, s_ip_hdr_ready_next;
reg s_ip_payload_axis_tready_reg = 1'b0, s_ip_payload_axis_tready_next;
reg m_eth_hdr_valid_reg = 1'b0, m_eth_hdr_valid_next;
reg [47:0] m_eth_dest_mac_reg = 48'd0;
reg [47:0] m_eth_src_mac_reg = 48'd0;
reg [15:0] m_eth_type_reg = 16'd0;
reg busy_reg = 1'b0;
reg error_payload_early_termination_reg = 1'b0, error_payload_early_termination_next;
reg [63:0] save_ip_payload_axis_tdata_reg = 64'd0;
reg [7:0] save_ip_payload_axis_tkeep_reg = 8'd0;
reg save_ip_payload_axis_tlast_reg = 1'b0;
reg save_ip_payload_axis_tuser_reg = 1'b0;
reg [63:0] shift_ip_payload_axis_tdata;
reg [7:0] shift_ip_payload_axis_tkeep;
reg shift_ip_payload_axis_tvalid;
reg shift_ip_payload_axis_tlast;
reg shift_ip_payload_axis_tuser;
reg shift_ip_payload_s_tready;
reg shift_ip_payload_extra_cycle_reg = 1'b0;
// internal datapath
reg [63:0] m_eth_payload_axis_tdata_int;
reg [7:0] m_eth_payload_axis_tkeep_int;
reg m_eth_payload_axis_tvalid_int;
reg m_eth_payload_axis_tready_int_reg = 1'b0;
reg m_eth_payload_axis_tlast_int;
reg m_eth_payload_axis_tuser_int;
wire m_eth_payload_axis_tready_int_early;
assign s_ip_hdr_ready = s_ip_hdr_ready_reg;
assign s_ip_payload_axis_tready = s_ip_payload_axis_tready_reg;
assign m_eth_hdr_valid = m_eth_hdr_valid_reg;
assign m_eth_dest_mac = m_eth_dest_mac_reg;
assign m_eth_src_mac = m_eth_src_mac_reg;
assign m_eth_type = m_eth_type_reg;
assign busy = busy_reg;
assign error_payload_early_termination = error_payload_early_termination_reg;
function [3:0] keep2count;
input [7:0] k;
casez (k)
8'bzzzzzzz0: keep2count = 4'd0;
8'bzzzzzz01: keep2count = 4'd1;
8'bzzzzz011: keep2count = 4'd2;
8'bzzzz0111: keep2count = 4'd3;
8'bzzz01111: keep2count = 4'd4;
8'bzz011111: keep2count = 4'd5;
8'bz0111111: keep2count = 4'd6;
8'b01111111: keep2count = 4'd7;
8'b11111111: keep2count = 4'd8;
endcase
endfunction
function [7:0] count2keep;
input [3:0] k;
case (k)
4'd0: count2keep = 8'b00000000;
4'd1: count2keep = 8'b00000001;
4'd2: count2keep = 8'b00000011;
4'd3: count2keep = 8'b00000111;
4'd4: count2keep = 8'b00001111;
4'd5: count2keep = 8'b00011111;
4'd6: count2keep = 8'b00111111;
4'd7: count2keep = 8'b01111111;
4'd8: count2keep = 8'b11111111;
endcase
endfunction
always @* begin
shift_ip_payload_axis_tdata[31:0] = save_ip_payload_axis_tdata_reg[63:32];
shift_ip_payload_axis_tkeep[3:0] = save_ip_payload_axis_tkeep_reg[7:4];
if (shift_ip_payload_extra_cycle_reg) begin
shift_ip_payload_axis_tdata[63:32] = 32'd0;
shift_ip_payload_axis_tkeep[7:4] = 4'd0;
shift_ip_payload_axis_tvalid = 1'b1;
shift_ip_payload_axis_tlast = save_ip_payload_axis_tlast_reg;
shift_ip_payload_axis_tuser = save_ip_payload_axis_tuser_reg;
shift_ip_payload_s_tready = flush_save;
end else begin
shift_ip_payload_axis_tdata[63:32] = s_ip_payload_axis_tdata[31:0];
shift_ip_payload_axis_tkeep[7:4] = s_ip_payload_axis_tkeep[3:0];
shift_ip_payload_axis_tvalid = s_ip_payload_axis_tvalid;
shift_ip_payload_axis_tlast = (s_ip_payload_axis_tlast && (s_ip_payload_axis_tkeep[7:4] == 0));
shift_ip_payload_axis_tuser = (s_ip_payload_axis_tuser && (s_ip_payload_axis_tkeep[7:4] == 0));
shift_ip_payload_s_tready = !(s_ip_payload_axis_tlast && s_ip_payload_axis_tvalid && transfer_in_save) && !save_ip_payload_axis_tlast_reg;
end
end
always @* begin
state_next = STATE_IDLE;
s_ip_hdr_ready_next = 1'b0;
s_ip_payload_axis_tready_next = 1'b0;
store_ip_hdr = 1'b0;
store_last_word = 1'b0;
flush_save = 1'b0;
transfer_in_save = 1'b0;
hdr_ptr_next = hdr_ptr_reg;
word_count_next = word_count_reg;
hdr_sum_temp = 20'd0;
hdr_sum_next = hdr_sum_reg;
m_eth_hdr_valid_next = m_eth_hdr_valid_reg && !m_eth_hdr_ready;
error_payload_early_termination_next = 1'b0;
m_eth_payload_axis_tdata_int = 1'b0;
m_eth_payload_axis_tkeep_int = 1'b0;
m_eth_payload_axis_tvalid_int = 1'b0;
m_eth_payload_axis_tlast_int = 1'b0;
m_eth_payload_axis_tuser_int = 1'b0;
case (state_reg)
STATE_IDLE: begin
// idle state - wait for data
hdr_ptr_next = 6'd0;
flush_save = 1'b1;
s_ip_hdr_ready_next = !m_eth_hdr_valid_next;
if (s_ip_hdr_ready && s_ip_hdr_valid) begin
store_ip_hdr = 1'b1;
hdr_sum_next = {4'd4, 4'd5, s_ip_dscp, s_ip_ecn} +
s_ip_length +
s_ip_identification +
{s_ip_flags, s_ip_fragment_offset} +
{s_ip_ttl, s_ip_protocol} +
s_ip_source_ip[31:16] +
s_ip_source_ip[15: 0] +
s_ip_dest_ip[31:16] +
s_ip_dest_ip[15: 0];
s_ip_hdr_ready_next = 1'b0;
m_eth_hdr_valid_next = 1'b1;
if (m_eth_payload_axis_tready_int_reg) begin
m_eth_payload_axis_tvalid_int = 1'b1;
m_eth_payload_axis_tdata_int[ 7: 0] = {4'd4, 4'd5}; // ip_version, ip_ihl
m_eth_payload_axis_tdata_int[15: 8] = {s_ip_dscp, s_ip_ecn};
m_eth_payload_axis_tdata_int[23:16] = s_ip_length[15: 8];
m_eth_payload_axis_tdata_int[31:24] = s_ip_length[ 7: 0];
m_eth_payload_axis_tdata_int[39:32] = s_ip_identification[15: 8];
m_eth_payload_axis_tdata_int[47:40] = s_ip_identification[ 7: 0];
m_eth_payload_axis_tdata_int[55:48] = {s_ip_flags, s_ip_fragment_offset[12: 8]};
m_eth_payload_axis_tdata_int[63:56] = s_ip_fragment_offset[ 7: 0];
m_eth_payload_axis_tkeep_int = 8'hff;
hdr_ptr_next = 6'd8;
end
state_next = STATE_WRITE_HEADER;
end else begin
state_next = STATE_IDLE;
end
end
STATE_WRITE_HEADER: begin
// write header
word_count_next = ip_length_reg - 5*4 + 4;
if (m_eth_payload_axis_tready_int_reg) begin
hdr_ptr_next = hdr_ptr_reg + 6'd8;
m_eth_payload_axis_tvalid_int = 1'b1;
state_next = STATE_WRITE_HEADER;
case (hdr_ptr_reg)
6'h00: begin
m_eth_payload_axis_tdata_int[ 7: 0] = {4'd4, 4'd5}; // ip_version, ip_ihl
m_eth_payload_axis_tdata_int[15: 8] = {ip_dscp_reg, ip_ecn_reg};
m_eth_payload_axis_tdata_int[23:16] = ip_length_reg[15: 8];
m_eth_payload_axis_tdata_int[31:24] = ip_length_reg[ 7: 0];
m_eth_payload_axis_tdata_int[39:32] = ip_identification_reg[15: 8];
m_eth_payload_axis_tdata_int[47:40] = ip_identification_reg[ 7: 0];
m_eth_payload_axis_tdata_int[55:48] = {ip_flags_reg, ip_fragment_offset_reg[12: 8]};
m_eth_payload_axis_tdata_int[63:56] = ip_fragment_offset_reg[ 7: 0];
m_eth_payload_axis_tkeep_int = 8'hff;
end
6'h08: begin
hdr_sum_temp = hdr_sum_reg[15:0] + hdr_sum_reg[19:16];
hdr_sum_temp = hdr_sum_temp[15:0] + hdr_sum_temp[16];
m_eth_payload_axis_tdata_int[ 7: 0] = ip_ttl_reg;
m_eth_payload_axis_tdata_int[15: 8] = ip_protocol_reg;
m_eth_payload_axis_tdata_int[23:16] = ~hdr_sum_temp[15: 8];
m_eth_payload_axis_tdata_int[31:24] = ~hdr_sum_temp[ 7: 0];
m_eth_payload_axis_tdata_int[39:32] = ip_source_ip_reg[31:24];
m_eth_payload_axis_tdata_int[47:40] = ip_source_ip_reg[23:16];
m_eth_payload_axis_tdata_int[55:48] = ip_source_ip_reg[15: 8];
m_eth_payload_axis_tdata_int[63:56] = ip_source_ip_reg[ 7: 0];
m_eth_payload_axis_tkeep_int = 8'hff;
s_ip_payload_axis_tready_next = m_eth_payload_axis_tready_int_early;
state_next = STATE_WRITE_HEADER_LAST;
end
endcase
end else begin
state_next = STATE_WRITE_HEADER;
end
end
STATE_WRITE_HEADER_LAST: begin
// last header word requires first payload word; process accordingly
s_ip_payload_axis_tready_next = m_eth_payload_axis_tready_int_early && shift_ip_payload_s_tready;
if (s_ip_payload_axis_tready && s_ip_payload_axis_tvalid) begin
m_eth_payload_axis_tvalid_int = 1'b1;
transfer_in_save = 1'b1;
m_eth_payload_axis_tdata_int[ 7: 0] = ip_dest_ip_reg[31:24];
m_eth_payload_axis_tdata_int[15: 8] = ip_dest_ip_reg[23:16];
m_eth_payload_axis_tdata_int[23:16] = ip_dest_ip_reg[15: 8];
m_eth_payload_axis_tdata_int[31:24] = ip_dest_ip_reg[ 7: 0];
m_eth_payload_axis_tdata_int[39:32] = shift_ip_payload_axis_tdata[39:32];
m_eth_payload_axis_tdata_int[47:40] = shift_ip_payload_axis_tdata[47:40];
m_eth_payload_axis_tdata_int[55:48] = shift_ip_payload_axis_tdata[55:48];
m_eth_payload_axis_tdata_int[63:56] = shift_ip_payload_axis_tdata[63:56];
m_eth_payload_axis_tkeep_int = {shift_ip_payload_axis_tkeep[7:4], 4'hF};
m_eth_payload_axis_tlast_int = shift_ip_payload_axis_tlast;
m_eth_payload_axis_tuser_int = shift_ip_payload_axis_tuser;
word_count_next = word_count_reg - 16'd8;
if (keep2count(m_eth_payload_axis_tkeep_int) >= word_count_reg) begin
// have entire payload
m_eth_payload_axis_tkeep_int = count2keep(word_count_reg);
if (shift_ip_payload_axis_tlast) begin
s_ip_hdr_ready_next = !m_eth_hdr_valid_next;
s_ip_payload_axis_tready_next = 1'b0;
state_next = STATE_IDLE;
end else begin
store_last_word = 1'b1;
s_ip_payload_axis_tready_next = shift_ip_payload_s_tready;
m_eth_payload_axis_tvalid_int = 1'b0;
state_next = STATE_WRITE_PAYLOAD_LAST;
end
end else begin
if (shift_ip_payload_axis_tlast) begin
// end of frame, but length does not match
error_payload_early_termination_next = 1'b1;
s_ip_payload_axis_tready_next = shift_ip_payload_s_tready;
m_eth_payload_axis_tuser_int = 1'b1;
state_next = STATE_WAIT_LAST;
end else begin
state_next = STATE_WRITE_PAYLOAD;
end
end
end else begin
state_next = STATE_WRITE_HEADER_LAST;
end
end
STATE_WRITE_PAYLOAD: begin
// write payload
s_ip_payload_axis_tready_next = m_eth_payload_axis_tready_int_early && shift_ip_payload_s_tready;
m_eth_payload_axis_tdata_int = shift_ip_payload_axis_tdata;
m_eth_payload_axis_tkeep_int = shift_ip_payload_axis_tkeep;
m_eth_payload_axis_tvalid_int = shift_ip_payload_axis_tvalid;
m_eth_payload_axis_tlast_int = shift_ip_payload_axis_tlast;
m_eth_payload_axis_tuser_int = shift_ip_payload_axis_tuser;
store_last_word = 1'b1;
if (m_eth_payload_axis_tready_int_reg && shift_ip_payload_axis_tvalid) begin
// word transfer through
word_count_next = word_count_reg - 16'd8;
transfer_in_save = 1'b1;
if (word_count_reg <= 8) begin
// have entire payload
m_eth_payload_axis_tkeep_int = count2keep(word_count_reg);
if (shift_ip_payload_axis_tlast) begin
if (keep2count(shift_ip_payload_axis_tkeep) < word_count_reg[4:0]) begin
// end of frame, but length does not match
error_payload_early_termination_next = 1'b1;
m_eth_payload_axis_tuser_int = 1'b1;
end
s_ip_payload_axis_tready_next = 1'b0;
flush_save = 1'b1;
s_ip_hdr_ready_next = !m_eth_hdr_valid_next;
state_next = STATE_IDLE;
end else begin
m_eth_payload_axis_tvalid_int = 1'b0;
state_next = STATE_WRITE_PAYLOAD_LAST;
end
end else begin
if (shift_ip_payload_axis_tlast) begin
// end of frame, but length does not match
error_payload_early_termination_next = 1'b1;
m_eth_payload_axis_tuser_int = 1'b1;
s_ip_payload_axis_tready_next = 1'b0;
flush_save = 1'b1;
s_ip_hdr_ready_next = !m_eth_hdr_valid_next;
state_next = STATE_IDLE;
end else begin
state_next = STATE_WRITE_PAYLOAD;
end
end
end else begin
state_next = STATE_WRITE_PAYLOAD;
end
end
STATE_WRITE_PAYLOAD_LAST: begin
// read and discard until end of frame
s_ip_payload_axis_tready_next = m_eth_payload_axis_tready_int_early && shift_ip_payload_s_tready;
m_eth_payload_axis_tdata_int = last_word_data_reg;
m_eth_payload_axis_tkeep_int = last_word_keep_reg;
m_eth_payload_axis_tvalid_int = shift_ip_payload_axis_tvalid && shift_ip_payload_axis_tlast;
m_eth_payload_axis_tlast_int = shift_ip_payload_axis_tlast;
m_eth_payload_axis_tuser_int = shift_ip_payload_axis_tuser;
if (m_eth_payload_axis_tready_int_reg && shift_ip_payload_axis_tvalid) begin
transfer_in_save = 1'b1;
if (shift_ip_payload_axis_tlast) begin
s_ip_hdr_ready_next = !m_eth_hdr_valid_next;
s_ip_payload_axis_tready_next = 1'b0;
state_next = STATE_IDLE;
end else begin
state_next = STATE_WRITE_PAYLOAD_LAST;
end
end else begin
state_next = STATE_WRITE_PAYLOAD_LAST;
end
end
STATE_WAIT_LAST: begin
// read and discard until end of frame
s_ip_payload_axis_tready_next = shift_ip_payload_s_tready;
if (shift_ip_payload_axis_tvalid) begin
transfer_in_save = 1'b1;
if (shift_ip_payload_axis_tlast) begin
s_ip_hdr_ready_next = !m_eth_hdr_valid_next;
s_ip_payload_axis_tready_next = 1'b0;
state_next = STATE_IDLE;
end else begin
state_next = STATE_WAIT_LAST;
end
end else begin
state_next = STATE_WAIT_LAST;
end
end
endcase
end
always @(posedge clk) begin
if (rst) begin
state_reg <= STATE_IDLE;
s_ip_hdr_ready_reg <= 1'b0;
s_ip_payload_axis_tready_reg <= 1'b0;
m_eth_hdr_valid_reg <= 1'b0;
save_ip_payload_axis_tlast_reg <= 1'b0;
shift_ip_payload_extra_cycle_reg <= 1'b0;
busy_reg <= 1'b0;
error_payload_early_termination_reg <= 1'b0;
end else begin
state_reg <= state_next;
s_ip_hdr_ready_reg <= s_ip_hdr_ready_next;
s_ip_payload_axis_tready_reg <= s_ip_payload_axis_tready_next;
m_eth_hdr_valid_reg <= m_eth_hdr_valid_next;
busy_reg <= state_next != STATE_IDLE;
error_payload_early_termination_reg <= error_payload_early_termination_next;
if (flush_save) begin
save_ip_payload_axis_tlast_reg <= 1'b0;
shift_ip_payload_extra_cycle_reg <= 1'b0;
end else if (transfer_in_save) begin
save_ip_payload_axis_tlast_reg <= s_ip_payload_axis_tlast;
shift_ip_payload_extra_cycle_reg <= s_ip_payload_axis_tlast && (s_ip_payload_axis_tkeep[7:4] != 0);
end
end
hdr_ptr_reg <= hdr_ptr_next;
word_count_reg <= word_count_next;
hdr_sum_reg <= hdr_sum_next;
// datapath
if (store_ip_hdr) begin
m_eth_dest_mac_reg <= s_eth_dest_mac;
m_eth_src_mac_reg <= s_eth_src_mac;
m_eth_type_reg <= s_eth_type;
ip_dscp_reg <= s_ip_dscp;
ip_ecn_reg <= s_ip_ecn;
ip_length_reg <= s_ip_length;
ip_identification_reg <= s_ip_identification;
ip_flags_reg <= s_ip_flags;
ip_fragment_offset_reg <= s_ip_fragment_offset;
ip_ttl_reg <= s_ip_ttl;
ip_protocol_reg <= s_ip_protocol;
ip_source_ip_reg <= s_ip_source_ip;
ip_dest_ip_reg <= s_ip_dest_ip;
end
if (store_last_word) begin
last_word_data_reg <= m_eth_payload_axis_tdata_int;
last_word_keep_reg <= m_eth_payload_axis_tkeep_int;
end
if (transfer_in_save) begin
save_ip_payload_axis_tdata_reg <= s_ip_payload_axis_tdata;
save_ip_payload_axis_tkeep_reg <= s_ip_payload_axis_tkeep;
save_ip_payload_axis_tuser_reg <= s_ip_payload_axis_tuser;
end
end
// output datapath logic
reg [63:0] m_eth_payload_axis_tdata_reg = 64'd0;
reg [7:0] m_eth_payload_axis_tkeep_reg = 8'd0;
reg m_eth_payload_axis_tvalid_reg = 1'b0, m_eth_payload_axis_tvalid_next;
reg m_eth_payload_axis_tlast_reg = 1'b0;
reg m_eth_payload_axis_tuser_reg = 1'b0;
reg [63:0] temp_m_eth_payload_axis_tdata_reg = 64'd0;
reg [7:0] temp_m_eth_payload_axis_tkeep_reg = 8'd0;
reg temp_m_eth_payload_axis_tvalid_reg = 1'b0, temp_m_eth_payload_axis_tvalid_next;
reg temp_m_eth_payload_axis_tlast_reg = 1'b0;
reg temp_m_eth_payload_axis_tuser_reg = 1'b0;
// datapath control
reg store_eth_payload_int_to_output;
reg store_eth_payload_int_to_temp;
reg store_eth_payload_axis_temp_to_output;
assign m_eth_payload_axis_tdata = m_eth_payload_axis_tdata_reg;
assign m_eth_payload_axis_tkeep = m_eth_payload_axis_tkeep_reg;
assign m_eth_payload_axis_tvalid = m_eth_payload_axis_tvalid_reg;
assign m_eth_payload_axis_tlast = m_eth_payload_axis_tlast_reg;
assign m_eth_payload_axis_tuser = m_eth_payload_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_eth_payload_axis_tready_int_early = m_eth_payload_axis_tready | (!temp_m_eth_payload_axis_tvalid_reg && (!m_eth_payload_axis_tvalid_reg | !m_eth_payload_axis_tvalid_int));
always @* begin
// transfer sink ready state to source
m_eth_payload_axis_tvalid_next = m_eth_payload_axis_tvalid_reg;
temp_m_eth_payload_axis_tvalid_next = temp_m_eth_payload_axis_tvalid_reg;
store_eth_payload_int_to_output = 1'b0;
store_eth_payload_int_to_temp = 1'b0;
store_eth_payload_axis_temp_to_output = 1'b0;
if (m_eth_payload_axis_tready_int_reg) begin
// input is ready
if (m_eth_payload_axis_tready | !m_eth_payload_axis_tvalid_reg) begin
// output is ready or currently not valid, transfer data to output
m_eth_payload_axis_tvalid_next = m_eth_payload_axis_tvalid_int;
store_eth_payload_int_to_output = 1'b1;
end else begin
// output is not ready, store input in temp
temp_m_eth_payload_axis_tvalid_next = m_eth_payload_axis_tvalid_int;
store_eth_payload_int_to_temp = 1'b1;
end
end else if (m_eth_payload_axis_tready) begin
// input is not ready, but output is ready
m_eth_payload_axis_tvalid_next = temp_m_eth_payload_axis_tvalid_reg;
temp_m_eth_payload_axis_tvalid_next = 1'b0;
store_eth_payload_axis_temp_to_output = 1'b1;
end
end
always @(posedge clk) begin
if (rst) begin
m_eth_payload_axis_tvalid_reg <= 1'b0;
m_eth_payload_axis_tready_int_reg <= 1'b0;
temp_m_eth_payload_axis_tvalid_reg <= 1'b0;
end else begin
m_eth_payload_axis_tvalid_reg <= m_eth_payload_axis_tvalid_next;
m_eth_payload_axis_tready_int_reg <= m_eth_payload_axis_tready_int_early;
temp_m_eth_payload_axis_tvalid_reg <= temp_m_eth_payload_axis_tvalid_next;
end
// datapath
if (store_eth_payload_int_to_output) begin
m_eth_payload_axis_tdata_reg <= m_eth_payload_axis_tdata_int;
m_eth_payload_axis_tkeep_reg <= m_eth_payload_axis_tkeep_int;
m_eth_payload_axis_tlast_reg <= m_eth_payload_axis_tlast_int;
m_eth_payload_axis_tuser_reg <= m_eth_payload_axis_tuser_int;
end else if (store_eth_payload_axis_temp_to_output) begin
m_eth_payload_axis_tdata_reg <= temp_m_eth_payload_axis_tdata_reg;
m_eth_payload_axis_tkeep_reg <= temp_m_eth_payload_axis_tkeep_reg;
m_eth_payload_axis_tlast_reg <= temp_m_eth_payload_axis_tlast_reg;
m_eth_payload_axis_tuser_reg <= temp_m_eth_payload_axis_tuser_reg;
end
if (store_eth_payload_int_to_temp) begin
temp_m_eth_payload_axis_tdata_reg <= m_eth_payload_axis_tdata_int;
temp_m_eth_payload_axis_tkeep_reg <= m_eth_payload_axis_tkeep_int;
temp_m_eth_payload_axis_tlast_reg <= m_eth_payload_axis_tlast_int;
temp_m_eth_payload_axis_tuser_reg <= m_eth_payload_axis_tuser_int;
end
end
endmodule
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