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corundum/rtl/ip_eth_rx_64.v

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/*
Copyright (c) 2014 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 receiver (Ethernet frame in, IP frame out, 64 bit datapath)
*/
module ip_eth_rx_64
(
input wire clk,
input wire rst,
/*
* Ethernet frame input
*/
input wire input_eth_hdr_valid,
output wire input_eth_hdr_ready,
input wire [47:0] input_eth_dest_mac,
input wire [47:0] input_eth_src_mac,
input wire [15:0] input_eth_type,
input wire [63:0] input_eth_payload_tdata,
input wire [7:0] input_eth_payload_tkeep,
input wire input_eth_payload_tvalid,
output wire input_eth_payload_tready,
input wire input_eth_payload_tlast,
input wire input_eth_payload_tuser,
/*
* IP frame output
*/
output wire output_ip_hdr_valid,
input wire output_ip_hdr_ready,
output wire [47:0] output_eth_dest_mac,
output wire [47:0] output_eth_src_mac,
output wire [15:0] output_eth_type,
output wire [3:0] output_ip_version,
output wire [3:0] output_ip_ihl,
output wire [5:0] output_ip_dscp,
output wire [1:0] output_ip_ecn,
output wire [15:0] output_ip_length,
output wire [15:0] output_ip_identification,
output wire [2:0] output_ip_flags,
output wire [12:0] output_ip_fragment_offset,
output wire [7:0] output_ip_ttl,
output wire [7:0] output_ip_protocol,
output wire [15:0] output_ip_header_checksum,
output wire [31:0] output_ip_source_ip,
output wire [31:0] output_ip_dest_ip,
output wire [63:0] output_ip_payload_tdata,
output wire [7:0] output_ip_payload_tkeep,
output wire output_ip_payload_tvalid,
input wire output_ip_payload_tready,
output wire output_ip_payload_tlast,
output wire output_ip_payload_tuser,
/*
* Status signals
*/
output wire busy,
output wire error_header_early_termination,
output wire error_payload_early_termination,
output wire error_invalid_header,
output wire error_invalid_checksum
);
/*
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 Ethernet frame with header fields in parallel and
payload on an AXI stream interface, decodes and strips the IP header fields,
then produces the header fields in parallel along with the IP payload in a
separate AXI stream.
*/
localparam [2:0]
STATE_IDLE = 3'd0,
STATE_READ_HEADER = 3'd1,
STATE_READ_PAYLOAD = 3'd2,
STATE_READ_PAYLOAD_LAST = 3'd3,
STATE_WAIT_LAST = 3'd4;
reg [2:0] state_reg = STATE_IDLE, state_next;
// datapath control signals
reg store_eth_hdr;
reg store_hdr_word_0;
reg store_hdr_word_1;
reg store_hdr_word_2;
reg store_last_word;
reg flush_save;
reg transfer_in_save;
reg [15:0] frame_ptr_reg = 0, frame_ptr_next;
reg [31:0] hdr_sum_temp;
reg [15:0] hdr_sum_reg = 0, hdr_sum_next;
reg [15:0] hdr_sum_temp_a_reg = 0, hdr_sum_temp_a_next;
reg [15:0] hdr_sum_temp_b_reg = 0, hdr_sum_temp_b_next;
reg [63:0] last_word_data_reg = 0;
reg [7:0] last_word_keep_reg = 0;
reg input_eth_hdr_ready_reg = 0, input_eth_hdr_ready_next;
reg input_eth_payload_tready_reg = 0, input_eth_payload_tready_next;
reg output_ip_hdr_valid_reg = 0, output_ip_hdr_valid_next;
reg [47:0] output_eth_dest_mac_reg = 0;
reg [47:0] output_eth_src_mac_reg = 0;
reg [15:0] output_eth_type_reg = 0;
reg [3:0] output_ip_version_reg = 0;
reg [3:0] output_ip_ihl_reg = 0;
reg [5:0] output_ip_dscp_reg = 0;
reg [1:0] output_ip_ecn_reg = 0;
reg [15:0] output_ip_length_reg = 0;
reg [15:0] output_ip_identification_reg = 0;
reg [2:0] output_ip_flags_reg = 0;
reg [12:0] output_ip_fragment_offset_reg = 0;
reg [7:0] output_ip_ttl_reg = 0;
reg [7:0] output_ip_protocol_reg = 0;
reg [15:0] output_ip_header_checksum_reg = 0;
reg [31:0] output_ip_source_ip_reg = 0;
reg [31:0] output_ip_dest_ip_reg = 0;
reg busy_reg = 0;
reg error_header_early_termination_reg = 0, error_header_early_termination_next;
reg error_payload_early_termination_reg = 0, error_payload_early_termination_next;
reg error_invalid_header_reg = 0, error_invalid_header_next;
reg error_invalid_checksum_reg = 0, error_invalid_checksum_next;
reg [63:0] save_eth_payload_tdata_reg = 0;
reg [7:0] save_eth_payload_tkeep_reg = 0;
reg save_eth_payload_tlast_reg = 0;
reg save_eth_payload_tuser_reg = 0;
reg [63:0] shift_eth_payload_tdata;
reg [7:0] shift_eth_payload_tkeep;
reg shift_eth_payload_tvalid;
reg shift_eth_payload_tlast;
reg shift_eth_payload_tuser;
reg shift_eth_payload_input_tready;
reg shift_eth_payload_extra_cycle;
// internal datapath
reg [63:0] output_ip_payload_tdata_int;
reg [7:0] output_ip_payload_tkeep_int;
reg output_ip_payload_tvalid_int;
reg output_ip_payload_tready_int = 0;
reg output_ip_payload_tlast_int;
reg output_ip_payload_tuser_int;
wire output_ip_payload_tready_int_early;
assign input_eth_hdr_ready = input_eth_hdr_ready_reg;
assign input_eth_payload_tready = input_eth_payload_tready_reg;
assign output_ip_hdr_valid = output_ip_hdr_valid_reg;
assign output_eth_dest_mac = output_eth_dest_mac_reg;
assign output_eth_src_mac = output_eth_src_mac_reg;
assign output_eth_type = output_eth_type_reg;
assign output_ip_version = output_ip_version_reg;
assign output_ip_ihl = output_ip_ihl_reg;
assign output_ip_dscp = output_ip_dscp_reg;
assign output_ip_ecn = output_ip_ecn_reg;
assign output_ip_length = output_ip_length_reg;
assign output_ip_identification = output_ip_identification_reg;
assign output_ip_flags = output_ip_flags_reg;
assign output_ip_fragment_offset = output_ip_fragment_offset_reg;
assign output_ip_ttl = output_ip_ttl_reg;
assign output_ip_protocol = output_ip_protocol_reg;
assign output_ip_header_checksum = output_ip_header_checksum_reg;
assign output_ip_source_ip = output_ip_source_ip_reg;
assign output_ip_dest_ip = output_ip_dest_ip_reg;
assign busy = busy_reg;
assign error_header_early_termination = error_header_early_termination_reg;
assign error_payload_early_termination = error_payload_early_termination_reg;
assign error_invalid_header = error_invalid_header_reg;
assign error_invalid_checksum = error_invalid_checksum_reg;
function [3:0] keep2count;
input [7:0] k;
case (k)
8'b00000000: keep2count = 0;
8'b00000001: keep2count = 1;
8'b00000011: keep2count = 2;
8'b00000111: keep2count = 3;
8'b00001111: keep2count = 4;
8'b00011111: keep2count = 5;
8'b00111111: keep2count = 6;
8'b01111111: keep2count = 7;
8'b11111111: keep2count = 8;
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_eth_payload_tdata[31:0] = save_eth_payload_tdata_reg[63:32];
shift_eth_payload_tkeep[3:0] = save_eth_payload_tkeep_reg[7:4];
shift_eth_payload_extra_cycle = save_eth_payload_tlast_reg & (save_eth_payload_tkeep_reg[7:4] != 0);
if (shift_eth_payload_extra_cycle) begin
shift_eth_payload_tdata[63:32] = 0;
shift_eth_payload_tkeep[7:4] = 0;
shift_eth_payload_tvalid = 1;
shift_eth_payload_tlast = save_eth_payload_tlast_reg;
shift_eth_payload_tuser = save_eth_payload_tuser_reg;
shift_eth_payload_input_tready = flush_save;
end else begin
shift_eth_payload_tdata[63:32] = input_eth_payload_tdata[31:0];
shift_eth_payload_tkeep[7:4] = input_eth_payload_tkeep[3:0];
shift_eth_payload_tvalid = input_eth_payload_tvalid;
shift_eth_payload_tlast = (input_eth_payload_tlast & (input_eth_payload_tkeep[7:4] == 0));
shift_eth_payload_tuser = (input_eth_payload_tuser & (input_eth_payload_tkeep[7:4] == 0));
shift_eth_payload_input_tready = ~(input_eth_payload_tlast & input_eth_payload_tvalid & transfer_in_save);
end
end
always @* begin
state_next = 2'bz;
flush_save = 0;
transfer_in_save = 0;
input_eth_hdr_ready_next = 0;
input_eth_payload_tready_next = 0;
store_eth_hdr = 0;
store_hdr_word_0 = 0;
store_hdr_word_1 = 0;
store_hdr_word_2 = 0;
store_last_word = 0;
frame_ptr_next = frame_ptr_reg;
hdr_sum_temp = 0;
hdr_sum_next = hdr_sum_reg;
hdr_sum_temp_a_next = hdr_sum_temp_a_reg;
hdr_sum_temp_b_next = hdr_sum_temp_b_reg;
output_ip_hdr_valid_next = output_ip_hdr_valid_reg & ~output_ip_hdr_ready;
error_header_early_termination_next = 0;
error_payload_early_termination_next = 0;
error_invalid_header_next = 0;
error_invalid_checksum_next = 0;
output_ip_payload_tdata_int = 0;
output_ip_payload_tkeep_int = 0;
output_ip_payload_tvalid_int = 0;
output_ip_payload_tlast_int = 0;
output_ip_payload_tuser_int = 0;
case (state_reg)
STATE_IDLE: begin
// idle state - wait for header
frame_ptr_next = 0;
hdr_sum_next = 0;
flush_save = 1;
input_eth_hdr_ready_next = ~output_ip_hdr_valid_reg;
if (input_eth_hdr_ready & input_eth_hdr_valid) begin
input_eth_hdr_ready_next = 0;
input_eth_payload_tready_next = 1;
store_eth_hdr = 1;
state_next = STATE_READ_HEADER;
end else begin
state_next = STATE_IDLE;
end
end
STATE_READ_HEADER: begin
// read header
input_eth_payload_tready_next = shift_eth_payload_input_tready;
if (input_eth_payload_tvalid) begin
// word transfer in - store it
frame_ptr_next = frame_ptr_reg+8;
transfer_in_save = 1;
state_next = STATE_READ_HEADER;
case (frame_ptr_reg)
8'h00: begin
store_hdr_word_0 = 1;
hdr_sum_temp = input_eth_payload_tdata[15:0] +
input_eth_payload_tdata[31:16] +
input_eth_payload_tdata[47:32] +
input_eth_payload_tdata[63:48];
hdr_sum_temp = hdr_sum_temp[15:0] + hdr_sum_temp[31:16];
hdr_sum_temp_a_next = hdr_sum_temp[15:0] + hdr_sum_temp[16];
end
8'h08: begin
store_hdr_word_1 = 1;
hdr_sum_temp = input_eth_payload_tdata[15:0] +
input_eth_payload_tdata[31:16] +
input_eth_payload_tdata[47:32] +
input_eth_payload_tdata[63:48];
hdr_sum_temp = hdr_sum_temp[15:0] + hdr_sum_temp[31:16];
hdr_sum_temp_b_next = hdr_sum_temp[15:0] + hdr_sum_temp[16];
end
8'h10: begin
store_hdr_word_2 = 1;
hdr_sum_temp = input_eth_payload_tdata[15:0] +
input_eth_payload_tdata[31:16] +
hdr_sum_temp_a_reg +
hdr_sum_temp_b_reg;
hdr_sum_temp = hdr_sum_temp[15:0] + hdr_sum_temp[31:16];
hdr_sum_next = hdr_sum_temp[15:0] + hdr_sum_temp[16];
frame_ptr_next = frame_ptr_reg+4;
if (output_ip_version_reg != 4 || output_ip_ihl_reg != 5) begin
error_invalid_header_next = 1;
input_eth_payload_tready_next = shift_eth_payload_input_tready;
state_next = STATE_WAIT_LAST;
end else if (hdr_sum_next != 16'hffff) begin
error_invalid_checksum_next = 1;
input_eth_payload_tready_next = shift_eth_payload_input_tready;
state_next = STATE_WAIT_LAST;
end else begin
output_ip_hdr_valid_next = 1;
input_eth_payload_tready_next = output_ip_payload_tready_int_early & shift_eth_payload_input_tready;
state_next = STATE_READ_PAYLOAD;
end
end
endcase
if (shift_eth_payload_tlast) begin
error_header_early_termination_next = 1;
error_invalid_header_next = 0;
error_invalid_checksum_next = 0;
output_ip_hdr_valid_next = 0;
input_eth_hdr_ready_next = ~output_ip_hdr_valid_reg;
input_eth_payload_tready_next = 0;
state_next = STATE_IDLE;
end
end else begin
state_next = STATE_READ_HEADER;
end
end
STATE_READ_PAYLOAD: begin
// read payload
input_eth_payload_tready_next = output_ip_payload_tready_int_early & shift_eth_payload_input_tready;
output_ip_payload_tdata_int = shift_eth_payload_tdata;
output_ip_payload_tkeep_int = shift_eth_payload_tkeep;
output_ip_payload_tvalid_int = shift_eth_payload_tvalid;
output_ip_payload_tlast_int = shift_eth_payload_tlast;
output_ip_payload_tuser_int = shift_eth_payload_tuser;
if (output_ip_payload_tready_int & shift_eth_payload_tvalid) begin
// word transfer through
frame_ptr_next = frame_ptr_reg+keep2count(shift_eth_payload_tkeep);
transfer_in_save = 1;
if (frame_ptr_next >= output_ip_length_reg) begin
// have entire payload
frame_ptr_next = output_ip_length_reg;
output_ip_payload_tkeep_int = shift_eth_payload_tkeep & count2keep(output_ip_length_reg - frame_ptr_reg);
if (shift_eth_payload_tlast) begin
input_eth_payload_tready_next = 0;
flush_save = 1;
input_eth_hdr_ready_next = ~output_ip_hdr_valid_reg;
state_next = STATE_IDLE;
end else begin
store_last_word = 1;
output_ip_payload_tvalid_int = 0;
state_next = STATE_READ_PAYLOAD_LAST;
end
end else begin
if (shift_eth_payload_tlast) begin
// end of frame, but length does not match
error_payload_early_termination_next = 1;
output_ip_payload_tuser_int = 1;
input_eth_payload_tready_next = 0;
flush_save = 1;
input_eth_hdr_ready_next = ~output_ip_hdr_valid_reg;
state_next = STATE_IDLE;
end else begin
state_next = STATE_READ_PAYLOAD;
end
end
end else begin
state_next = STATE_READ_PAYLOAD;
end
end
STATE_READ_PAYLOAD_LAST: begin
// read and discard until end of frame
input_eth_payload_tready_next = output_ip_payload_tready_int_early & shift_eth_payload_input_tready;
output_ip_payload_tdata_int = last_word_data_reg;
output_ip_payload_tkeep_int = last_word_keep_reg;
output_ip_payload_tvalid_int = shift_eth_payload_tvalid & shift_eth_payload_tlast;
output_ip_payload_tlast_int = shift_eth_payload_tlast;
output_ip_payload_tuser_int = shift_eth_payload_tuser;
if (output_ip_payload_tready_int & shift_eth_payload_tvalid) begin
transfer_in_save = 1;
if (shift_eth_payload_tlast) begin
input_eth_payload_tready_next = 0;
flush_save = 1;
input_eth_hdr_ready_next = 1;
state_next = STATE_IDLE;
end else begin
state_next = STATE_READ_PAYLOAD_LAST;
end
end else begin
state_next = STATE_READ_PAYLOAD_LAST;
end
end
STATE_WAIT_LAST: begin
// read and discard until end of frame
input_eth_payload_tready_next = shift_eth_payload_input_tready;
if (shift_eth_payload_tvalid) begin
transfer_in_save = 1;
if (shift_eth_payload_tlast) begin
input_eth_payload_tready_next = 0;
flush_save = 1;
input_eth_hdr_ready_next = 1;
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 or posedge rst) begin
if (rst) begin
state_reg <= STATE_IDLE;
frame_ptr_reg <= 0;
hdr_sum_reg <= 0;
hdr_sum_temp_a_reg <= 0;
hdr_sum_temp_b_reg <= 0;
last_word_data_reg <= 0;
last_word_keep_reg <= 0;
input_eth_hdr_ready_reg <= 0;
input_eth_payload_tready_reg <= 0;
output_ip_hdr_valid_reg <= 0;
output_eth_dest_mac_reg <= 0;
output_eth_src_mac_reg <= 0;
output_eth_type_reg <= 0;
output_ip_version_reg <= 0;
output_ip_ihl_reg <= 0;
output_ip_dscp_reg <= 0;
output_ip_ecn_reg <= 0;
output_ip_length_reg <= 0;
output_ip_identification_reg <= 0;
output_ip_flags_reg <= 0;
output_ip_fragment_offset_reg <= 0;
output_ip_ttl_reg <= 0;
output_ip_protocol_reg <= 0;
output_ip_header_checksum_reg <= 0;
output_ip_source_ip_reg <= 0;
output_ip_dest_ip_reg <= 0;
output_ip_payload_tdata_reg <= 0;
output_ip_payload_tvalid_reg <= 0;
output_ip_payload_tlast_reg <= 0;
output_ip_payload_tuser_reg <= 0;
save_eth_payload_tdata_reg <= 0;
save_eth_payload_tkeep_reg <= 0;
save_eth_payload_tlast_reg <= 0;
save_eth_payload_tuser_reg <= 0;
busy_reg <= 0;
error_header_early_termination_reg <= 0;
error_payload_early_termination_reg <= 0;
error_invalid_header_reg <= 0;
error_invalid_checksum_reg <= 0;
end else begin
state_reg <= state_next;
frame_ptr_reg <= frame_ptr_next;
hdr_sum_reg <= hdr_sum_next;
hdr_sum_temp_a_reg <= hdr_sum_temp_a_next;
hdr_sum_temp_b_reg <= hdr_sum_temp_b_next;
input_eth_hdr_ready_reg <= input_eth_hdr_ready_next;
input_eth_payload_tready_reg <= input_eth_payload_tready_next;
output_ip_hdr_valid_reg <= output_ip_hdr_valid_next;
error_header_early_termination_reg <= error_header_early_termination_next;
error_payload_early_termination_reg <= error_payload_early_termination_next;
error_invalid_header_reg <= error_invalid_header_next;
error_invalid_checksum_reg <= error_invalid_checksum_next;
busy_reg <= state_next != STATE_IDLE;
// datapath
if (store_eth_hdr) begin
output_eth_dest_mac_reg <= input_eth_dest_mac;
output_eth_src_mac_reg <= input_eth_src_mac;
output_eth_type_reg <= input_eth_type;
end
if (store_last_word) begin
last_word_data_reg <= output_ip_payload_tdata_int;
last_word_keep_reg <= output_ip_payload_tkeep_int;
end
if (store_hdr_word_0) begin
{output_ip_version_reg, output_ip_ihl_reg} <= input_eth_payload_tdata[ 7: 0];
{output_ip_dscp_reg, output_ip_ecn_reg} <= input_eth_payload_tdata[15: 8];
output_ip_length_reg[15: 8] <= input_eth_payload_tdata[23:16];
output_ip_length_reg[ 7: 0] <= input_eth_payload_tdata[31:24];
output_ip_identification_reg[15: 8] <= input_eth_payload_tdata[39:32];
output_ip_identification_reg[ 7: 0] <= input_eth_payload_tdata[47:40];
{output_ip_flags_reg, output_ip_fragment_offset_reg[12:8]} <= input_eth_payload_tdata[55:48];
output_ip_fragment_offset_reg[ 7:0] <= input_eth_payload_tdata[63:56];
end
if (store_hdr_word_1) begin
output_ip_ttl_reg <= input_eth_payload_tdata[ 7: 0];
output_ip_protocol_reg <= input_eth_payload_tdata[15: 8];
output_ip_header_checksum_reg[15: 8] <= input_eth_payload_tdata[23:16];
output_ip_header_checksum_reg[ 7: 0] <= input_eth_payload_tdata[31:24];
output_ip_source_ip_reg[31:24] <= input_eth_payload_tdata[39:32];
output_ip_source_ip_reg[23:16] <= input_eth_payload_tdata[47:40];
output_ip_source_ip_reg[15: 8] <= input_eth_payload_tdata[55:48];
output_ip_source_ip_reg[ 7: 0] <= input_eth_payload_tdata[63:56];
end
if (store_hdr_word_2) begin
output_ip_dest_ip_reg[31:24] <= input_eth_payload_tdata[ 7: 0];
output_ip_dest_ip_reg[23:16] <= input_eth_payload_tdata[15: 8];
output_ip_dest_ip_reg[15: 8] <= input_eth_payload_tdata[23:16];
output_ip_dest_ip_reg[ 7: 0] <= input_eth_payload_tdata[31:24];
end
if (flush_save) begin
save_eth_payload_tdata_reg <= 0;
save_eth_payload_tkeep_reg <= 0;
save_eth_payload_tlast_reg <= 0;
save_eth_payload_tuser_reg <= 0;
end else if (transfer_in_save) begin
save_eth_payload_tdata_reg <= input_eth_payload_tdata;
save_eth_payload_tkeep_reg <= input_eth_payload_tkeep;
save_eth_payload_tlast_reg <= input_eth_payload_tlast;
save_eth_payload_tuser_reg <= input_eth_payload_tuser;
end
end
end
// output datapath logic
reg [63:0] output_ip_payload_tdata_reg = 0;
reg [7:0] output_ip_payload_tkeep_reg = 0;
reg output_ip_payload_tvalid_reg = 0;
reg output_ip_payload_tlast_reg = 0;
reg output_ip_payload_tuser_reg = 0;
reg [63:0] temp_ip_payload_tdata_reg = 0;
reg [7:0] temp_ip_payload_tkeep_reg = 0;
reg temp_ip_payload_tvalid_reg = 0;
reg temp_ip_payload_tlast_reg = 0;
reg temp_ip_payload_tuser_reg = 0;
// enable ready input next cycle if output is ready or if there is space in both output registers or if there is space in the temp register that will not be filled next cycle
assign output_ip_payload_tready_int_early = output_ip_payload_tready | (~temp_ip_payload_tvalid_reg & ~output_ip_payload_tvalid_reg) | (~temp_ip_payload_tvalid_reg & ~output_ip_payload_tvalid_int);
assign output_ip_payload_tdata = output_ip_payload_tdata_reg;
assign output_ip_payload_tkeep = output_ip_payload_tkeep_reg;
assign output_ip_payload_tvalid = output_ip_payload_tvalid_reg;
assign output_ip_payload_tlast = output_ip_payload_tlast_reg;
assign output_ip_payload_tuser = output_ip_payload_tuser_reg;
always @(posedge clk or posedge rst) begin
if (rst) begin
output_ip_payload_tdata_reg <= 0;
output_ip_payload_tkeep_reg <= 0;
output_ip_payload_tvalid_reg <= 0;
output_ip_payload_tlast_reg <= 0;
output_ip_payload_tuser_reg <= 0;
output_ip_payload_tready_int <= 0;
temp_ip_payload_tdata_reg <= 0;
temp_ip_payload_tkeep_reg <= 0;
temp_ip_payload_tvalid_reg <= 0;
temp_ip_payload_tlast_reg <= 0;
temp_ip_payload_tuser_reg <= 0;
end else begin
// transfer sink ready state to source
output_ip_payload_tready_int <= output_ip_payload_tready_int_early;
if (output_ip_payload_tready_int) begin
// input is ready
if (output_ip_payload_tready | ~output_ip_payload_tvalid_reg) begin
// output is ready or currently not valid, transfer data to output
output_ip_payload_tdata_reg <= output_ip_payload_tdata_int;
output_ip_payload_tkeep_reg <= output_ip_payload_tkeep_int;
output_ip_payload_tvalid_reg <= output_ip_payload_tvalid_int;
output_ip_payload_tlast_reg <= output_ip_payload_tlast_int;
output_ip_payload_tuser_reg <= output_ip_payload_tuser_int;
end else begin
// output is not ready and currently valid, store input in temp
temp_ip_payload_tdata_reg <= output_ip_payload_tdata_int;
temp_ip_payload_tkeep_reg <= output_ip_payload_tkeep_int;
temp_ip_payload_tvalid_reg <= output_ip_payload_tvalid_int;
temp_ip_payload_tlast_reg <= output_ip_payload_tlast_int;
temp_ip_payload_tuser_reg <= output_ip_payload_tuser_int;
end
end else if (output_ip_payload_tready) begin
// input is not ready, but output is ready
output_ip_payload_tdata_reg <= temp_ip_payload_tdata_reg;
output_ip_payload_tkeep_reg <= temp_ip_payload_tkeep_reg;
output_ip_payload_tvalid_reg <= temp_ip_payload_tvalid_reg;
output_ip_payload_tlast_reg <= temp_ip_payload_tlast_reg;
output_ip_payload_tuser_reg <= temp_ip_payload_tuser_reg;
temp_ip_payload_tdata_reg <= 0;
temp_ip_payload_tkeep_reg <= 0;
temp_ip_payload_tvalid_reg <= 0;
temp_ip_payload_tlast_reg <= 0;
temp_ip_payload_tuser_reg <= 0;
end
end
end
endmodule
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