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//////////////////////////////////////////////////////////////////////
////                                                              ////
////  Ethernet MAC Stimulus                                       ////
////                                                              ////
////  Description                                                 ////
////  Ethernet MAC stimulus tasks. Taken from the project         ////
////  testbench in the ethmac core.                               ////
////                                                              ////
////  To Do:                                                      ////
////                                                              ////
////                                                              ////
////  Author(s):                                                  ////
////      - Tadej Markovic, tadej@opencores.org                   ////
////      - Igor Mohor,     igorM@opencores.org                   ////
////      - Julius Baxter   julius.baxter@orsoc.se                ////
////                                                              ////
////                                                              ////
//////////////////////////////////////////////////////////////////////
////                                                              ////
//// Copyright (C) 2009 Authors and OPENCORES.ORG                 ////
////                                                              ////
//// This source file may be used and distributed without         ////
//// restriction provided that this copyright statement is not    ////
//// removed from the file and that any derivative work contains  ////
//// the original copyright notice and the associated disclaimer. ////
////                                                              ////
//// This source file is free software; you can redistribute it   ////
//// and/or modify it under the terms of the GNU Lesser General   ////
//// Public License as published by the Free Software Foundation; ////
//// either version 2.1 of the License, or (at your option) any   ////
//// later version.                                               ////
////                                                              ////
//// This source 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.  See the GNU Lesser General Public License for more ////
//// details.                                                     ////
////                                                              ////
//// You should have received a copy of the GNU Lesser General    ////
//// Public License along with this source; if not, download it   ////
//// from http://www.opencores.org/lgpl.shtml                     ////
////                                                              ////
//////////////////////////////////////////////////////////////////////
`define TIME $display("Time: %0t", $time)
 
// Defines for ethernet test to trigger sending/receiving
// Is straight forward when using RTL design, but if using netlist then paths to
// the RX/TX enabled bits depend on synthesis tool, etc, but ones here appear to
// work with design put through Synplify, with hierarchy maintained.
`define ETH_TOP dut.ethmac0
`define ETH_BD_RAM_PATH `ETH_TOP.wishbone.bd_ram
`define ETH_MODER_PATH `ETH_TOP.ethreg1.MODER_0
 
`ifdef RTL_SIM
 `ifdef ethmac_IS_GATELEVEL
  `define ETH_MODER_TXEN_BIT `ETH_MODER_PATH.r_TxEn;
  `define ETH_MODER_RXEN_BIT `ETH_MODER_PATH.r_RxEn;
 `else
  `define ETH_MODER_TXEN_BIT `ETH_MODER_PATH.DataOut[1];
  `define ETH_MODER_RXEN_BIT `ETH_MODER_PATH.DataOut[0];
 `endif
`endif
 
`ifdef GATE_SIM
 `define ETH_MODER_TXEN_BIT `ETH_MODER_PATH.r_TxEn;
 `define ETH_MODER_RXEN_BIT `ETH_MODER_PATH.r_RxEn;
`endif
 
reg [15:0] eth_stim_rx_packet_length;
reg [7:0] st_data;
reg [31:0] lfsr;
integer lfsr_last_byte;
 
// Is number of ethernet packets to send if doing the eth-rx test.
parameter eth_stim_num_rx_only_num_packets = 500; // Set to 0 for continuous RX
parameter eth_stim_num_rx_only_packet_size = 512;
parameter eth_stim_num_rx_only_packet_size_change = 2'b01;  // 2'b01: Increment
parameter eth_stim_num_rx_only_packet_size_change_amount = 1;
parameter eth_stim_num_rx_only_IPG = 800000; // ns
 
// Do call/response test
reg eth_stim_do_rx_reponse_to_tx;
 
 
parameter num_tx_bds = 16;
parameter num_tx_bds_mask = 4'hf;
parameter num_rx_bds = 16;
parameter num_rx_bds_mask = 4'hf;
parameter max_eth_packet_size = 16'h0600;
 
// If running eth-rxtxbig test (sending and receiving maximum packets), then
// set this parameter to the max packet size, otherwise min packet size
//parameter rx_while_tx_min_packet_size = max_eth_packet_size;
parameter rx_while_tx_min_packet_size = 32;
 
// Use the smallest possible IPG
parameter eth_stim_use_min_IPG = 0;
parameter eth_stim_IPG_delay_max = 500_000; // Maximum 500uS ga
//parameter eth_stim_IPG_delay_max = 100_000_000; // Maximum 100mS between packets
parameter eth_stim_IPG_min_10mb = 9600; // 9.6 uS
parameter eth_stim_IPG_min_100mb = 800; // 860+~100 = 960 nS 100MBit min IPG
parameter eth_stim_check_rx_packet_contents = 1;
parameter eth_stim_check_tx_packet_contents = 1;
 
parameter eth_inject_errors = 0;
 
// When running simulations where you don't want to feed packets to the design
// like this...
parameter eth_stim_disable_rx_stim = 0;
 
// Delay between seeing that the buffer descriptor for an RX packet says it's
// been received and ending up in the memory.
// For 25MHz sdram controller, use following:
//parameter  Td_rx_packet_check = (`BOARD_CLOCK_PERIOD * 2000);
// For 64MHz sdram controller, use following:
parameter  Td_rx_packet_check = (`BOARD_CLOCK_PERIOD * 500);
 
 
 
integer expected_rxbd;// init to 0
integer expected_txbd;
 
wire ethmac_rxen;
wire ethmac_txen;
assign ethmac_rxen = eth_stim_disable_rx_stim ? 0 : `ETH_MODER_RXEN_BIT;
assign ethmac_txen = `ETH_MODER_TXEN_BIT;
 
integer eth_rx_num_packets_sent = 0;
integer eth_rx_num_packets_checked = 0;
integer num_tx_packets = 1;
 
integer rx_packet_lengths [0:1023]; // Array of packet lengths
 
 
integer speed_loop;
 
// When txen is (re)enabled, the tx bd pointer goes back to 0
always @(posedge ethmac_txen)
  expected_txbd = 0;
 
   reg  eth_stim_waiting;
 
initial
  begin
     #1;
     //lfsr = 32'h84218421; // Init pseudo lfsr
     lfsr = 32'h00700001; // Init pseudo lfsr
     lfsr_last_byte = 0;
 
     eth_stim_waiting = 1;
     expected_rxbd = num_tx_bds; // init this here
 
     eth_stim_do_rx_reponse_to_tx = 0;
 
 
     while (eth_stim_waiting) // Loop, waiting for enabling of MAC by software
       begin
          #100;
          // If RX enable and not TX enable...
          if(ethmac_rxen === 1'b1 & !(ethmac_txen===1'b1))
            begin
               if (eth_inject_errors)
                 begin
                    do_rx_only_stim(16, 64, 0, 0);
                    do_rx_only_stim(128, 64, 1'b1, 8);
                    do_rx_only_stim(256, 64, 1'b1, 4);
                    eth_stim_waiting = 0;
                 end
               else
                 begin
                    //do_rx_only_stim(eth_stim_num_rx_only_num_packets, 
                    //eth_stim_num_rx_only_packet_size, 0, 0);
 
                    // Call packet send loop directly. No error injection.
                    send_packet_loop(eth_stim_num_rx_only_num_packets,
                                     eth_stim_num_rx_only_packet_size,
                                     eth_stim_num_rx_only_packet_size_change,
                                     eth_stim_num_rx_only_packet_size_change_amount,
                                     eth_phy0.eth_speed,     // Speed
                                     eth_stim_num_rx_only_IPG, // IPG
                               48'h0012_3456_789a, 48'h0708_090A_0B0C, 1,
                               0, 0);
 
                    eth_stim_waiting = 0;
                 end
            end // if (ethmac_rxen === 1'b1 & !(ethmac_txen===1'b1))
          // If both RX and TX enabled
          else if (ethmac_rxen === 1'b1 & ethmac_txen===1'b1)
            begin
               // Both enabled - let's wait for the first packet transmitted
               // to see what stimulus we should provide
               while (num_tx_packets==1)
                 #1000;
 
               $display("* ethmac RX/TX test request: %x", eth_phy0.tx_mem[0]);
 
               // Check the first received byte's value
                 case (eth_phy0.tx_mem[0])
                   0:
                     begin
                        // kickoff call/response here
                        eth_stim_do_rx_reponse_to_tx = 1;
                     end
                   default:
                     begin
                        do_rx_while_tx_stim(1400);
                     end
                 endcase // case (eth_phy0.tx_mem[0])
 
               eth_stim_waiting = 0;
            end
       end // while (eth_stim_waiting)     
 
  end // initial begin
 
   // Main Ethernet RX testing stimulus task.
   // Sends a set of packets at both speeds
   task do_rx_only_stim;
      input [31:0] num_packets;
      input [31:0] start_packet_size;
      input        inject_errors;
      input [31:0] inject_errors_mod;
 
      begin
 
         for(speed_loop=1;speed_loop<3;speed_loop=speed_loop+1)
           begin
 
              send_packet_loop(num_packets, start_packet_size, 2'b01, 1,
                               speed_loop[0], 10000,
                               48'h0012_3456_789a, 48'h0708_090A_0B0C, 1,
                               inject_errors, inject_errors_mod);
 
           end
 
      end
   endtask // do_rx_stim
 
   // Generate RX packets while there's TX going on
   // Sends a set of packets at both speeds
   task do_rx_while_tx_stim;
      input [31:0] num_packets;
      reg [31:0] IPG; // Inter-packet gap
      reg [31:0] packet_size;
 
      integer    j;
      begin
 
         for(j=0;j<num_packets;j=j+1)
           begin
              // Determine delay between RX packets:
 
              if (eth_stim_use_min_IPG)
                begin
                   // Assign based on whether we're in 100mbit or 10mbit mode
                   IPG = eth_phy0.eth_speed ? eth_stim_IPG_min_100mb :
                         eth_stim_IPG_min_10mb;
                   // Add a little bit of variability
                   // Add up to 15
                   IPG = IPG + ($random & 32'h000000f);
                end
              else
                begin
                   IPG = $random;
 
                   while (IPG > eth_stim_IPG_delay_max)
                     IPG = IPG / 2;
 
 
                end
              $display("do_rx_while_tx IPG = %0d", IPG);
              // Determine size of next packet:
              if (rx_while_tx_min_packet_size == max_eth_packet_size)
                // We want to transmit biggest packets possible, easy case
                packet_size = max_eth_packet_size - 4;
              else
                begin
                   // Constrained random sized packets
                   packet_size = $random;
 
                   while (packet_size > (max_eth_packet_size-4))
                     packet_size = packet_size / 2;
 
                   // Now divide by least significant bits of j
                   packet_size = packet_size / {29'd0,j[1:0],1'b1};
                   if (packet_size < 60)
                     packet_size = packet_size + 60;
                end
 
              $display("do_rx_while_tx packet_size = %0d", packet_size);
              send_packet_loop(1, packet_size, 2'b01, 1, eth_phy0.eth_speed,
                               IPG, 48'h0012_3456_789a,
                               48'h0708_090A_0B0C, 1, 1'b0, 0);
 
              // If RX enable went low, wait for it go high again
              if (ethmac_rxen===1'b0)
                begin
 
                   while (ethmac_rxen===1'b0)
                     begin
                        @(posedge ethmac_rxen);
                        #10000;
                     end
 
                   // RX disabled and when re-enabled we reset the buffer descriptor number
                   expected_rxbd = num_tx_bds;
 
                end
 
           end // for (j=0;j<num_packets;j=j+1)
      end
   endtask // do_rx_stim
 
   // Registers used in detecting transmitted packets
   reg eth_stim_tx_loop_keep_polling;
   reg [31:0] ethmac_txbd_lenstat, ethmac_last_txbd_lenstat;
   reg        eth_stim_detected_packet_tx;
 
   // If in call-response mode, whenever we receive a TX packet, we generate
   // one and send it back
   always @(negedge eth_stim_detected_packet_tx)
     begin
        if (eth_stim_do_rx_reponse_to_tx & ethmac_rxen)
          // Continue if we are enabled
          do_rx_response_to_tx();
     end
 
   // Generate RX packet in rsponse to TX packet
   task do_rx_response_to_tx;
      //input unused;
 
     reg [31:0] IPG; // Inter-packet gap
      reg [31:0] packet_size;
 
      integer    j;
      begin
 
         // Get packet size test wants us to send
         packet_size = {eth_phy0.tx_mem[0],eth_phy0.tx_mem[1],
                        eth_phy0.tx_mem[2],eth_phy0.tx_mem[3]};
 
 
         IPG = {eth_phy0.tx_mem[4],eth_phy0.tx_mem[5],
                eth_phy0.tx_mem[6],eth_phy0.tx_mem[7]};
 
 
         $display("do_rx_response_to_tx IPG = %0d", IPG);
         if (packet_size == 0)
           begin
              // Constrained random sized packets
              packet_size = $random;
 
              while (packet_size > (max_eth_packet_size-4))
                packet_size = packet_size / 2;
 
              if (packet_size < 60)
                packet_size = packet_size + 60;
           end
 
         $display("do_rx_response_to_tx packet_size = %0d", packet_size);
         send_packet_loop(1, packet_size, 2'b01, 1, eth_phy0.eth_speed,
                          IPG, 48'h0012_3456_789a,
                          48'h0708_090A_0B0C, 1, 1'b0, 0);
 
         // If RX enable went low, wait for it go high again
         if (ethmac_rxen===1'b0)
           begin
 
              while (ethmac_rxen===1'b0)
                begin
                   @(posedge ethmac_rxen);
                   #10000;
                end
 
              // RX disabled and when re-enabled we reset the buffer 
              // descriptor number
              expected_rxbd = num_tx_bds;
 
           end
 
      end
   endtask // do_rx_response_to_tx
 
 
 
 
 
   //
   // always@() to check the TX buffer descriptors
   //
   always @(posedge ethmac_txen)
     begin
         ethmac_last_txbd_lenstat = 0;
         eth_stim_tx_loop_keep_polling=1;
         // Wait on the TxBD Ready bit
         while(eth_stim_tx_loop_keep_polling)
           begin
              #10;
              get_bd_lenstat(expected_txbd, ethmac_txbd_lenstat);
              // Check if we've finished transmitting this BD
              if (!ethmac_txbd_lenstat[15] & ethmac_last_txbd_lenstat[15])
                // Falling edge of TX BD Ready
                eth_stim_detected_packet_tx = 1;
 
              ethmac_last_txbd_lenstat = ethmac_txbd_lenstat;
 
              // If TX en goes low then exit
              if (!ethmac_txen)
                eth_stim_tx_loop_keep_polling = 0;
              else if (eth_stim_detected_packet_tx)
                begin
                   // Wait until the eth_phy has finished receiving it
                   while (eth_phy0.mtxen_i === 1'b1)
                     #10;
 
                   $display("(%t) Check TX packet: bd %d: 0x%h",$time,
                            expected_txbd, ethmac_txbd_lenstat);
 
                   // Check the TXBD, see if the packet transmitted OK
                   if (ethmac_txbd_lenstat[8] | ethmac_txbd_lenstat[3])
                     begin
                        // Error occured
                        `TIME;
                        $display("*E TX Error of packet %0d detected.",
                                 num_tx_packets);
                        $display(" TX BD %0d = 0x%h", expected_txbd,
                                 ethmac_txbd_lenstat);
                        if (ethmac_txbd_lenstat[8])
                          $display(" Underrun in MAC during TX");
                        if (ethmac_txbd_lenstat[3])
                          $display(" Retransmission limit hit");
 
                        $finish;
                     end
                   else
                     begin
                        // Packet was OK, let's compare the contents we 
                        // received with those that were meant to be transmitted
                        if (eth_stim_check_tx_packet_contents)
                          begin
                             check_tx_packet(expected_txbd);
                             expected_txbd = (expected_txbd + 1) &
                                             num_tx_bds_mask;
                             num_tx_packets = num_tx_packets + 1;
                             eth_stim_detected_packet_tx = 0;
                          end
                     end
                end
           end // while (eth_stim_tx_loop_keep_polling)
     end // always @ (posedge ethmac_txen)
 
 
 
   //
   // Check packet TX'd by MAC was good
   // 
   task check_tx_packet;
      input [31:0] tx_bd_num;
 
      reg [31:0]   tx_bd_addr;
      reg [7:0]    phy_byte;
 
      reg [31:0]   txpnt_wb; // Pointer in array to where data should be
      reg [24:0]   txpnt_sdram; // Index in array of shorts for data in SDRAM 
                                // part
      reg [21:0]   buffer;
      reg [7:0]    sdram_byte;
      reg [31:0]   tx_len_bd;
 
      integer      i;
      integer      failure;
      begin
         failure = 0;
 
         get_bd_lenstat(tx_bd_num, tx_len_bd);
 
         tx_len_bd = {15'd0,tx_len_bd[31:16]};
 
         // Check, if length didn't have to be padded, that
         // amount transmitted was correct
         if ((tx_len_bd > 60)&(tx_len_bd != (eth_phy0.tx_len-4)))
           begin
              $display("*E TX packet sent length, %0d != length in TX BD, %0d",
                       eth_phy0.tx_len-4, tx_len_bd);
              #100;
              $finish;
           end
 
         get_bd_addr(tx_bd_num, tx_bd_addr);
 
         // We're never going to be using more than about 256K of receive buffer
         // so let's lop off the top bit of the address pointer - we only want
         // the offset from the base of the memory bank
         txpnt_wb = {14'd0,tx_bd_addr[17:0]};
         txpnt_sdram = tx_bd_addr[24:0];
 
         // Variable we'll use for index in the PHY's TX buffer
         buffer = 0; // Start of TX data
`ifdef VERSATILE_SDRAM
         for (i=0;i<tx_len_bd;i=i+1)
           begin
              //$display("Checking address in tx bd 0x%0h",txpnt_sdram);
 
              sdram0.get_byte(txpnt_sdram,sdram_byte);
 
              phy_byte = eth_phy0.tx_mem[buffer];
              // Debugging output
              //$display("txpnt_sdram = 0x%h, sdram_byte = 0x%h, buffer = 0x%h, phy_byte = 0x%h", txpnt_sdram,  sdram_byte, buffer, phy_byte);
              if (phy_byte !== sdram_byte)
                begin
                   `TIME;
                   $display("*E Wrong byte (%d) of TX packet! ram = %h, phy = %h",buffer, sdram_byte, phy_byte);
                   failure = 1;
                end
 
              buffer = buffer + 1;
 
              txpnt_sdram = txpnt_sdram+1;
 
           end // for (i=0;i<tx_len_bd;i=i+1)
 
`else
         $display("SET ME UP TO LOOK IN ANOTHER MEMORY!");
         $display("RAM pointer for BD is 0x%h, bank offset we'll use is 0x%h",
                  tx_bd_addr, txpnt_wb);
         $finish;
`endif // !`ifdef VERSATILE_SDRAM
         if (failure)
           begin
              #100
                `TIME;
              $display("*E Error transmitting packet %0d (%0d bytes). Finishing simulation", num_tx_packets, tx_len_bd);
              get_bd_lenstat(tx_bd_num, tx_len_bd);
              $display("   TXBD lenstat: 0x%0h",tx_len_bd);
              $display("   TXBD address: 0x%0h",tx_bd_addr);
              $finish;
           end
         else
           begin
              #1 $display( "(%0t)(%m) TX packet %0d: %0d bytes in memory OK!",$time,num_tx_packets, tx_len_bd);
 
           end
 
 
      end
   endtask // check_tx_packet
 
   //
   // Task to send a set of packets
   //
   task send_packet_loop;
      input [31:0] num_packets;
      input [31:0] length;
      input [1:0]  length_change; // 0 = none, 1 = incr, 2 = decrement
      input [31:0] length_change_size; // Size to change by
      input        speed;
      input [31:0] back_to_back_delay; // #delay setting between packets
      input [47:0] dst_mac;
      input [47:0] src_mac;
      input        random_fill;
      input        random_errors;
      input [31:0] random_error_mod;
      integer      j;
      reg          error_this_time;
      integer      error_type; // 0 = rxerr, 1=bad preamble 2=bad crc 3=TODO
      reg [31:0]   rx_bd_lenstat;
      begin
         error_type = 0;
         error_this_time = 0;
 
         if (num_packets == 0)
           // Loop forever when num_packets is 0
           num_packets = 32'h7fffffff;
 
 
         if (speed & !(eth_phy0.control_bit14_10[13] === 1'b1))
           begin
              // write to phy's control register for 100Mbps
              eth_phy0.control_bit14_10 = 5'b01000; // bit 13 set - speed 100
              // Swapping speeds, give some delay
              #10000;
           end
         else if (!speed & !(eth_phy0.control_bit14_10[13] === 1'b0))
           begin
              eth_phy0.control_bit14_10 = 5'b00000; // bit 13 reset - speed 10
              // Swapping speeds, give some delay
              #10000;
           end
 
         eth_phy0.control_bit8_0   = 9'h1_00;
 
         for(j=0;j<num_packets | length <32;j=j+1)
           begin
              eth_stim_rx_packet_length = length[15:0]; // Bytes
              st_data = 8'h0F;
 
              // setup RX packet in buffer - length is without CRC
              set_rx_packet(0, eth_stim_rx_packet_length, 1'b0, dst_mac,
                            src_mac, 16'h0D0E, st_data, random_fill);
 
              set_rx_addr_type(0, dst_mac, src_mac, 16'h0D0E);
 
              // Error type 2 is cause CRC error
              append_rx_crc(0, eth_stim_rx_packet_length, 1'b0,
                            (error_type==2));
 
              if (error_this_time)
                begin
                   if (error_type == 0)
                     // RX ERR assert during transmit
                     eth_phy0.send_rx_packet(64'h0055_5555_5555_5555, 4'h7,
                                             8'hD5, 0,
                                             eth_stim_rx_packet_length+4,
                                             1'b0, 1'b1);
                   else if (error_type == 1)
                     // Incorrect preamble
                     eth_phy0.send_rx_packet(64'h0055_5f55_5555_5555, 4'h7,
                                             8'hD5, 0,
                                             eth_stim_rx_packet_length+4,
                                             1'b0, 1'b0);
                   else
                     // Normal datapacket
                     eth_phy0.send_rx_packet(64'h0055_5555_5555_5555, 4'h7,
                                             8'hD5, 0,
                                             eth_stim_rx_packet_length+4,
                                             1'b0, 1'b0);
                end
              else
                eth_phy0.send_rx_packet(64'h0055_5555_5555_5555, 4'h7, 8'hD5,
                                        0, eth_stim_rx_packet_length+4, 1'b0,
                                        1'b0);
 
 
              // if RX enable still set (might have gone low during this packet
              if (ethmac_rxen)
                begin
                   if (error_this_time)
                     // Put in dummy length, checking function will skip...
                     rx_packet_lengths[(eth_rx_num_packets_sent& 12'h3ff)]=32'heeeeeeee;
                   else
                     rx_packet_lengths[(eth_rx_num_packets_sent & 12'h3ff)] = length;
 
                   eth_rx_num_packets_sent = eth_rx_num_packets_sent + 1;
 
                end // if (ethmac_rxen)
              else
                begin
                   // Force the loop to finish up                  
                   j = num_packets;
                end
 
 
              // Inter-packet gap
              #back_to_back_delay;
 
              // Update length
              if (length_change == 2'b01)
                length = length + length_change_size;
 
              if ((length_change == 2'b10) &&
                  ((length - length_change_size) > 32))
                length = length - length_change_size;
 
              // Increment error type
              if (error_this_time)
                error_type = error_type + 1;
              if (error_type > 3)
                error_type = 0;
 
 
              // Check if we should put in an error this time
              if (j%random_error_mod == 0)
                error_this_time = 1;
              else
                error_this_time = 0;
 
              eth_phy0.rx_err(0);
 
              // Now wait to check if we have filled up all the RX BDs and
              // the this packet would start writing over them. Only really an
              // issue when doing minimum IPG tests.
              while(((eth_rx_num_packets_sent+1) - eth_rx_num_packets_checked)
                    == num_rx_bds)
                #100;
 
 
           end // for (j=0;j<num_packets | length <32;j=j+1)
      end
   endtask // send_packet_loop
 
   // Local buffer of "sent" data to the ethernet MAC, we will check against
   // Size of our local buffer in bytes
   parameter eth_rx_sent_circbuf_size = (16*1024);
   parameter eth_rx_sent_circbuf_size_mask = eth_rx_sent_circbuf_size - 1;
   integer eth_rx_sent_circbuf_fill_ptr = 0;
   integer eth_rx_sent_circbuf_read_ptr = 0;
   // The actual buffer
   reg [7:0] eth_rx_sent_circbuf [0:eth_rx_sent_circbuf_size-1];
 
   /*
    TASKS for set and check RX packets:
    -----------------------------------
    set_rx_packet
    (rxpnt[31:0], len[15:0], plus_nibble, d_addr[47:0], s_addr[47:0], type_len[15:0], start_data[7:0]);
    check_rx_packet
    (rxpnt_phy[31:0], rxpnt_wb[31:0], len[15:0], plus_nibble, successful_nibble, failure[31:0]);
    */
   task set_rx_packet;
      input  [31:0] rxpnt; // pointer to place in in the phy rx buffer we'll start at
      input [15:0]  len;
      input         plus_dribble_nibble; // if length is longer for one nibble
      input [47:0]  eth_dest_addr;
      input [47:0]  eth_source_addr;
      input [15:0]  eth_type_len;
      input [7:0]   eth_start_data;
      input         random_fill;
      integer       i, sd;
      reg [47:0]    dest_addr;
      reg [47:0]    source_addr;
      reg [15:0]    type_len;
      reg [21:0]    buffer;
      reg           delta_t;
 
      begin
         buffer = rxpnt[21:0];
         dest_addr = eth_dest_addr;
         source_addr = eth_source_addr;
         type_len = eth_type_len;
         sd = eth_start_data;
         delta_t = 0;
         for(i = 0; i < len; i = i + 1)
           begin
              if (i < 6)
                begin
                   eth_phy0.rx_mem[buffer] = dest_addr[47:40];
                   dest_addr = dest_addr << 8;
                end
              else if (i < 12)
                begin
                   eth_phy0.rx_mem[buffer] = source_addr[47:40];
                   source_addr = source_addr << 8;
                end
              else if (i < 14)
                begin
                   eth_phy0.rx_mem[buffer] = type_len[15:8];
                   type_len = type_len << 8;
                end
              else
                begin
                   if (random_fill)
                     begin
                        if (lfsr_last_byte == 0)
                          eth_phy0.rx_mem[buffer] = lfsr[15:8];
                        if (lfsr_last_byte == 1)
                          eth_phy0.rx_mem[buffer] = lfsr[23:16];
                        if (lfsr_last_byte == 2)
                          eth_phy0.rx_mem[buffer] = lfsr[31:24];
                        if (lfsr_last_byte == 3)
                          begin
                             eth_phy0.rx_mem[buffer] = lfsr[7:0];
                             lfsr = {lfsr[30:0],(((lfsr[31] ^ lfsr[6]) ^
                                                  lfsr[5]) ^ lfsr[1])};
                             lfsr_last_byte =  0;
                          end
                        else
                          lfsr_last_byte = lfsr_last_byte + 1;
 
                     end // if (random_fill)               
                   else
                     eth_phy0.rx_mem[buffer] = sd[7:0];
                   sd = sd + 1;
                end // else: !if(i < 14)
 
              // Update our local buffer
              eth_rx_sent_circbuf[eth_rx_sent_circbuf_fill_ptr]
                = eth_phy0.rx_mem[buffer];
              eth_rx_sent_circbuf_fill_ptr = (eth_rx_sent_circbuf_fill_ptr+1)&
                                             eth_rx_sent_circbuf_size_mask;
 
              buffer = buffer + 1;
           end // for (i = 0; i < len; i = i + 1)
 
         delta_t = !delta_t;
         if (plus_dribble_nibble)
           eth_phy0.rx_mem[buffer] = {4'h0, 4'hD /*sd[3:0]*/};
         delta_t = !delta_t;
      end
   endtask // set_rx_packet
 
 
 
 
   task set_rx_addr_type;
      input  [31:0] rxpnt;
      input [47:0]  eth_dest_addr;
      input [47:0]  eth_source_addr;
      input [15:0]  eth_type_len;
      integer       i;
      reg [47:0]    dest_addr;
      reg [47:0]    source_addr;
      reg [15:0]    type_len;
      reg [21:0]    buffer;
      reg           delta_t;
      begin
         buffer = rxpnt[21:0];
         dest_addr = eth_dest_addr;
         source_addr = eth_source_addr;
         type_len = eth_type_len;
         delta_t = 0;
         for(i = 0; i < 14; i = i + 1)
           begin
              if (i < 6)
                begin
                   eth_phy0.rx_mem[buffer] = dest_addr[47:40];
                   dest_addr = dest_addr << 8;
                end
              else if (i < 12)
                begin
                   eth_phy0.rx_mem[buffer] = source_addr[47:40];
                   source_addr = source_addr << 8;
                end
              else // if (i < 14)
                begin
                   eth_phy0.rx_mem[buffer] = type_len[15:8];
                   type_len = type_len << 8;
                end
              buffer = buffer + 1;
           end
         delta_t = !delta_t;
      end
   endtask // set_rx_addr_type
 
 
   // Check if we're using a synthesized version of eth module
`ifdef ethmac_IS_GATELEVEL
 
   // Get the length/status register of the ethernet buffer descriptor
   task get_bd_lenstat;
      input [31:0] bd_num;// Number of ethernet BD to check
      output [31:0] bd_lenstat;
 `ifdef ACTEL
      reg [8:0]    tmp;
      integer      raddr;
 `endif
      begin
 `ifdef ACTEL
 
         // Pull from the Actel memory model
         raddr = `ETH_BD_RAM_PATH.\mem_tile.I_1 .get_address((bd_num*2));
 
         tmp = `ETH_BD_RAM_PATH.\mem_tile.I_1 .MEM_512_9[(raddr*2)];
         bd_lenstat[8:0] = tmp[8:0];
 
         tmp = `ETH_BD_RAM_PATH.\mem_tile.I_1 .MEM_512_9[(raddr*2)+1];
         bd_lenstat[17:9] = tmp[8:0];
 
         raddr = `ETH_BD_RAM_PATH.\mem_tile_0.I_1 .get_address((bd_num*2));
 
         tmp = `ETH_BD_RAM_PATH.\mem_tile_0.I_1 .MEM_512_9[(raddr*2)];
         bd_lenstat[26:18] = tmp[8:0];
 
         tmp = `ETH_BD_RAM_PATH.\mem_tile_0.I_1 .MEM_512_9[(raddr*2)+1];
         bd_lenstat[31:27] = tmp[4:0];
 
         //$display("(%t) read eth bd lenstat %h",$time, bd_lenstat);
 `endif
      end
   endtask // get_bd_lenstat
 
   // Get the length/status register of the ethernet buffer descriptor
   task get_bd_addr;
      input [31:0] bd_num;// Number of the ethernet BD to check
      output [31:0] bd_addr;
 `ifdef ACTEL
      reg [8:0]    tmp;
      integer       raddr;
 `endif
      begin
 `ifdef ACTEL
         // Pull from the Actel memory model
         raddr = `ETH_BD_RAM_PATH.\mem_tile.I_1 .get_address((bd_num*2)+1);
 
         tmp = `ETH_BD_RAM_PATH.\mem_tile.I_1 .MEM_512_9[(raddr*2)];
         bd_addr[8:0] = tmp[8:0];
 
         tmp = `ETH_BD_RAM_PATH.\mem_tile.I_1 .MEM_512_9[(raddr*2)+1];
         bd_addr[17:9] = tmp[8:0];
 
         raddr = `ETH_BD_RAM_PATH.\mem_tile_0.I_1 .get_address((bd_num*2)+1);
 
         tmp = `ETH_BD_RAM_PATH.\mem_tile_0.I_1 .MEM_512_9[(raddr*2)];
         bd_addr[26:18] = tmp[8:0];
 
         tmp = `ETH_BD_RAM_PATH.\mem_tile_0.I_1 .MEM_512_9[(raddr*2)+1];
         bd_addr[31:27] = tmp[4:0];
 
         //$display("(%t) read eth bd%d addr %h",$time,bd_num, bd_addr);
 `endif
      end
   endtask // get_bd_addr
 
`else // !`ifdef ethmac_IS_GATELEVEL
 
   // Get the length/status register of the ethernet buffer descriptor
   task get_bd_lenstat;
      input [31:0] bd_num;// Number of ethernet BD to check
      output [31:0] bd_lenstat;
      begin
         bd_lenstat = `ETH_BD_RAM_PATH.mem[(bd_num*2)];
      end
   endtask // get_bd_lenstat
 
   // Get the length/status register of the ethernet buffer descriptor
   task get_bd_addr;
      input [31:0] bd_num;// Number of the ethernet BD to check
      output [31:0] bd_addr;
      begin
         bd_addr = `ETH_BD_RAM_PATH.mem[((bd_num*2)+1)];
         //$display("(%t) read eth bd%d addr %h",$time,bd_num, bd_addr);
      end
   endtask // get_bd_addr
`endif
 
   // Always block triggered by finishing of transmission of new packet from 
   // send_packet_loop
   integer eth_rx_packet_length_to_check;
 
   always @*
     begin
        // Loop here until:
        // 1 - packets sent is not equal to packets checked (ie. some to check)
        // 2 - we're explicitly disabled for some reason
        // 3 - Receive has been disabled in the MAC
        while((eth_rx_num_packets_sent == eth_rx_num_packets_checked) ||
              !eth_stim_check_rx_packet_contents || !(ethmac_rxen===1'b1))
          #1000;
 
        eth_rx_packet_length_to_check
          = rx_packet_lengths[(eth_rx_num_packets_checked & 12'h3ff)];
 
        if ( eth_rx_packet_length_to_check !==  32'heeeeeeee)
          check_rx_packet(expected_rxbd, 0, eth_rx_packet_length_to_check);
 
        eth_rx_num_packets_checked = eth_rx_num_packets_checked + 1;
 
        expected_rxbd = expected_rxbd + 1;
 
        // Wrap
        if (expected_rxbd == (num_tx_bds + num_rx_bds))
          expected_rxbd = num_tx_bds;
     end
 
   task check_rx_packet;
 
      input [31:0] rx_bd_num;
      input [31:0] rxpnt_phy; // Pointer in array of data in PHY
      input [31:0] len;
 
      reg [31:0]   rx_bd_lenstat;
      reg [31:0]   rx_bd_addr;
      reg [7:0]    phy_byte;
 
      reg [31:0]   rxpnt_wb; // Pointer in array to where data should be
      reg [24:0]   rxpnt_sdram; // byte address from CPU in RAM
      reg [15:0]   sdram_short;
      reg [7:0]    sdram_byte;
      //reg [7:0]    phy_rx_mem [0:2000];
 
      integer      i;
      integer      failure;
 
      begin
 
         failure = 0;
 
         // Wait until the buffer descriptor indicates the packet has been 
         // received...
         get_bd_lenstat(rx_bd_num, rx_bd_lenstat);
         while (rx_bd_lenstat & 32'h00008000)// Check Empty bit
           begin
              #10;
              get_bd_lenstat(rx_bd_num, rx_bd_lenstat);
              //$display("(%t) check_rx_packet: poll bd %d: 0x%h",$time,
                //        rx_bd_num, rx_bd_lenstat);
           end
 
 
         // Delay some time - takes a bit for the Wishbone FSM to pipe out the
         // packet over Wishbone and into whatever memory it's going into
         #Td_rx_packet_check;
 
         // Ok, buffer filled, let's get its offset in memory
         get_bd_addr(rx_bd_num, rx_bd_addr);
 
         $display("(%t) Check RX packet: bd %d: 0x%h, addr 0x%h",$time,
                  rx_bd_num, rx_bd_lenstat, rx_bd_addr);
 
 
         // We're never going to be using more than about 256KB of receive buffer
         // so let's lop off the top bit of the address pointer - we only want
         // the offset from the base of the memory bank
 
         rxpnt_wb = {14'd0,rx_bd_addr[17:0]};
         rxpnt_sdram = rx_bd_addr[24:0];
 
`ifdef VERSATILE_SDRAM
         // We'll look inside the SDRAM array
         // Hard coded for the SDRAM buffer area to be from the halfway mark in
         // memory (so starting in Bank2)
         // We'll be passed the offset from the beginning of the buffer area
         // in rxpnt_wb. This value will be in bytes.
 
         //$display("RAM pointer for BD is 0x%h, SDRAM addr is 0x%h", rx_bd_addr, rxpnt_sdram);
 
 
         for (i=0;i<len;i=i+1)
           begin
 
              sdram0.get_byte(rxpnt_sdram,sdram_byte);
 
              phy_byte = eth_rx_sent_circbuf[eth_rx_sent_circbuf_read_ptr];//phy_rx_mem[buffer]; //eth_phy0.rx_mem[buffer];
 
              if (phy_byte !== sdram_byte)
                begin
//                 `TIME;                 
                   $display("*E Wrong byte (%5d) of RX packet %5d! phy = %h, ram = %h",
                            i, eth_rx_num_packets_checked, phy_byte, sdram_byte);
                   failure = 1;
                end
 
              eth_rx_sent_circbuf_read_ptr = (eth_rx_sent_circbuf_read_ptr+1)&
                                             eth_rx_sent_circbuf_size_mask;
 
              rxpnt_sdram = rxpnt_sdram+1;
 
           end // for (i=0;i<len;i=i+2)
`else
 
         $display("SET ME UP TO LOOK IN ANOTHER MEMORY!");
         $display("RAM pointer for BD is 0x%h, bank offset we'll use is 0x%h",
                  rx_bd_addr, rxpnt_wb);
         $finish;
 
 
`endif // !`ifdef VERSATILE_SDRAM
 
         if (failure)
           begin
              #100
                `TIME;
              $display("*E Recieved packet %0d, length %0d bytes, had an error. Finishing simulation.", eth_rx_num_packets_checked, len);
              $finish;
           end
         else
           begin
              #1 $display( "(%0t)(%m) RX packet %0d: %0d bytes in memory OK!",$time,eth_rx_num_packets_checked, len);
 
           end
      end
   endtask // check_rx_packet
 
 
   //////////////////////////////////////////////////////////////
   // Ethernet CRC Basic tasks
   //////////////////////////////////////////////////////////////
 
   task append_rx_crc;
      input  [31:0] rxpnt_phy; // source
      input [15:0]  len; // length in bytes without CRC
      input         plus_dribble_nibble; // if length is longer for one nibble
      input         negated_crc; // if appended CRC is correct or not
      reg [31:0]    crc;
      reg [7:0]     tmp;
      reg [31:0]    addr_phy;
      reg           delta_t;
      begin
         addr_phy = rxpnt_phy + len;
         delta_t = 0;
         // calculate CRC from prepared packet
         paralel_crc_phy_rx(rxpnt_phy, {16'h0, len}, plus_dribble_nibble, crc);
         if (negated_crc)
           crc = ~crc;
         delta_t = !delta_t;
 
         if (plus_dribble_nibble)
           begin
              tmp = eth_phy0.rx_mem[addr_phy];
              eth_phy0.rx_mem[addr_phy]     = {crc[27:24], tmp[3:0]};
              eth_phy0.rx_mem[addr_phy + 1] = {crc[19:16], crc[31:28]};
              eth_phy0.rx_mem[addr_phy + 2] = {crc[11:8], crc[23:20]};
              eth_phy0.rx_mem[addr_phy + 3] = {crc[3:0], crc[15:12]};
              eth_phy0.rx_mem[addr_phy + 4] = {4'h0, crc[7:4]};
           end
         else
           begin
              eth_phy0.rx_mem[addr_phy]     = crc[31:24];
              eth_phy0.rx_mem[addr_phy + 1] = crc[23:16];
              eth_phy0.rx_mem[addr_phy + 2] = crc[15:8];
              eth_phy0.rx_mem[addr_phy + 3] = crc[7:0];
           end
      end
   endtask // append_rx_crc
 
   task append_rx_crc_delayed;
      input  [31:0] rxpnt_phy; // source
      input [15:0]  len; // length in bytes without CRC
      input         plus_dribble_nibble; // if length is longer for one nibble
      input         negated_crc; // if appended CRC is correct or not
      reg [31:0]    crc;
      reg [7:0]     tmp;
      reg [31:0]    addr_phy;
      reg           delta_t;
      begin
         addr_phy = rxpnt_phy + len;
         delta_t = 0;
         // calculate CRC from prepared packet
         paralel_crc_phy_rx(rxpnt_phy+4, {16'h0, len}-4, plus_dribble_nibble, crc);
         if (negated_crc)
           crc = ~crc;
         delta_t = !delta_t;
 
         if (plus_dribble_nibble)
           begin
              tmp = eth_phy0.rx_mem[addr_phy];
              eth_phy0.rx_mem[addr_phy]     = {crc[27:24], tmp[3:0]};
              eth_phy0.rx_mem[addr_phy + 1] = {crc[19:16], crc[31:28]};
              eth_phy0.rx_mem[addr_phy + 2] = {crc[11:8], crc[23:20]};
              eth_phy0.rx_mem[addr_phy + 3] = {crc[3:0], crc[15:12]};
              eth_phy0.rx_mem[addr_phy + 4] = {4'h0, crc[7:4]};
           end
         else
           begin
              eth_phy0.rx_mem[addr_phy]     = crc[31:24];
              eth_phy0.rx_mem[addr_phy + 1] = crc[23:16];
              eth_phy0.rx_mem[addr_phy + 2] = crc[15:8];
              eth_phy0.rx_mem[addr_phy + 3] = crc[7:0];
           end
      end
   endtask // append_rx_crc_delayed
 
 
   // paralel CRC calculating for PHY RX
   task paralel_crc_phy_rx;
      input  [31:0] start_addr; // start address
      input [31:0]  len; // length of frame in Bytes without CRC length
      input         plus_dribble_nibble; // if length is longer for one nibble
      output [31:0] crc_out;
      reg [21:0]    addr_cnt; // only 22 address lines
      integer       word_cnt;
      integer       nibble_cnt;
      reg [31:0]    load_reg;
      reg           delta_t;
      reg [31:0]    crc_next;
      reg [31:0]    crc;
      reg           crc_error;
      reg [3:0]     data_in;
      integer       i;
      begin
         #1 addr_cnt = start_addr[21:0];
         word_cnt = 24; // 27; // start of the frame - nibble granularity (MSbit first)
         crc = 32'hFFFF_FFFF; // INITIAL value
         delta_t = 0;
         // length must include 4 bytes of ZEROs, to generate CRC
         // get number of nibbles from Byte length (2^1 = 2)
         if (plus_dribble_nibble)
           nibble_cnt = ((len + 4) << 1) + 1'b1; // one nibble longer
         else
           nibble_cnt = ((len + 4) << 1);
         // because of MAGIC NUMBER nibbles are swapped [3:0] -> [0:3]
         load_reg[31:24] = eth_phy0.rx_mem[addr_cnt];
         addr_cnt = addr_cnt + 1;
         load_reg[23:16] = eth_phy0.rx_mem[addr_cnt];
         addr_cnt = addr_cnt + 1;
         load_reg[15: 8] = eth_phy0.rx_mem[addr_cnt];
         addr_cnt = addr_cnt + 1;
         load_reg[ 7: 0] = eth_phy0.rx_mem[addr_cnt];
         addr_cnt = addr_cnt + 1;
         while (nibble_cnt > 0)
           begin
              // wait for delta time
              delta_t = !delta_t;
              // shift data in
 
              if(nibble_cnt <= 8) // for additional 8 nibbles shift ZEROs in!
                data_in[3:0] = 4'h0;
              else
 
                data_in[3:0] = {load_reg[word_cnt], load_reg[word_cnt+1], load_reg[word_cnt+2], load_reg[word_cnt+3]};
              crc_next[0]  = (data_in[0] ^ crc[28]);
              crc_next[1]  = (data_in[1] ^ data_in[0] ^ crc[28]    ^ crc[29]);
              crc_next[2]  = (data_in[2] ^ data_in[1] ^ data_in[0] ^ crc[28]  ^ crc[29] ^ crc[30]);
              crc_next[3]  = (data_in[3] ^ data_in[2] ^ data_in[1] ^ crc[29]  ^ crc[30] ^ crc[31]);
              crc_next[4]  = (data_in[3] ^ data_in[2] ^ data_in[0] ^ crc[28]  ^ crc[30] ^ crc[31]) ^ crc[0];
              crc_next[5]  = (data_in[3] ^ data_in[1] ^ data_in[0] ^ crc[28]  ^ crc[29] ^ crc[31]) ^ crc[1];
              crc_next[6]  = (data_in[2] ^ data_in[1] ^ crc[29]    ^ crc[30]) ^ crc[ 2];
              crc_next[7]  = (data_in[3] ^ data_in[2] ^ data_in[0] ^ crc[28]  ^ crc[30] ^ crc[31]) ^ crc[3];
              crc_next[8]  = (data_in[3] ^ data_in[1] ^ data_in[0] ^ crc[28]  ^ crc[29] ^ crc[31]) ^ crc[4];
              crc_next[9]  = (data_in[2] ^ data_in[1] ^ crc[29]    ^ crc[30]) ^ crc[5];
              crc_next[10] = (data_in[3] ^ data_in[2] ^ data_in[0] ^ crc[28]  ^ crc[30] ^ crc[31]) ^ crc[6];
              crc_next[11] = (data_in[3] ^ data_in[1] ^ data_in[0] ^ crc[28]  ^ crc[29] ^ crc[31]) ^ crc[7];
              crc_next[12] = (data_in[2] ^ data_in[1] ^ data_in[0] ^ crc[28]  ^ crc[29] ^ crc[30]) ^ crc[8];
              crc_next[13] = (data_in[3] ^ data_in[2] ^ data_in[1] ^ crc[29]  ^ crc[30] ^ crc[31]) ^ crc[9];
              crc_next[14] = (data_in[3] ^ data_in[2] ^ crc[30]    ^ crc[31]) ^ crc[10];
              crc_next[15] = (data_in[3] ^ crc[31])   ^ crc[11];
              crc_next[16] = (data_in[0] ^ crc[28])   ^ crc[12];
              crc_next[17] = (data_in[1] ^ crc[29])   ^ crc[13];
              crc_next[18] = (data_in[2] ^ crc[30])   ^ crc[14];
              crc_next[19] = (data_in[3] ^ crc[31])   ^ crc[15];
              crc_next[20] =  crc[16];
              crc_next[21] =  crc[17];
              crc_next[22] = (data_in[0] ^ crc[28])   ^ crc[18];
              crc_next[23] = (data_in[1] ^ data_in[0] ^ crc[29]    ^ crc[28]) ^ crc[19];
              crc_next[24] = (data_in[2] ^ data_in[1] ^ crc[30]    ^ crc[29]) ^ crc[20];
              crc_next[25] = (data_in[3] ^ data_in[2] ^ crc[31]    ^ crc[30]) ^ crc[21];
              crc_next[26] = (data_in[3] ^ data_in[0] ^ crc[31]    ^ crc[28]) ^ crc[22];
              crc_next[27] = (data_in[1] ^ crc[29])   ^ crc[23];
              crc_next[28] = (data_in[2] ^ crc[30])   ^ crc[24];
              crc_next[29] = (data_in[3] ^ crc[31])   ^ crc[25];
              crc_next[30] =  crc[26];
              crc_next[31] =  crc[27];
 
              crc = crc_next;
              crc_error = crc[31:0] != 32'hc704dd7b;  // CRC not equal to magic number
              case (nibble_cnt)
                9: crc_out = {!crc[24], !crc[25], !crc[26], !crc[27], !crc[28], !crc[29], !crc[30], !crc[31],
                              !crc[16], !crc[17], !crc[18], !crc[19], !crc[20], !crc[21], !crc[22], !crc[23],
                              !crc[ 8], !crc[ 9], !crc[10], !crc[11], !crc[12], !crc[13], !crc[14], !crc[15],
                              !crc[ 0], !crc[ 1], !crc[ 2], !crc[ 3], !crc[ 4], !crc[ 5], !crc[ 6], !crc[ 7]};
                default: crc_out = crc_out;
              endcase
              // wait for delta time
              delta_t = !delta_t;
              // increment address and load new data
              if ((word_cnt+3) == 7)//4)
                begin
                   // because of MAGIC NUMBER nibbles are swapped [3:0] -> [0:3]
                   load_reg[31:24] = eth_phy0.rx_mem[addr_cnt];
                   addr_cnt = addr_cnt + 1;
                   load_reg[23:16] = eth_phy0.rx_mem[addr_cnt];
                   addr_cnt = addr_cnt + 1;
                   load_reg[15: 8] = eth_phy0.rx_mem[addr_cnt];
                   addr_cnt = addr_cnt + 1;
                   load_reg[ 7: 0] = eth_phy0.rx_mem[addr_cnt];
                   addr_cnt = addr_cnt + 1;
                end
              // set new load bit position
              if((word_cnt+3) == 31)
                word_cnt = 16;
              else if ((word_cnt+3) == 23)
                word_cnt = 8;
              else if ((word_cnt+3) == 15)
                word_cnt = 0;
              else if ((word_cnt+3) == 7)
                word_cnt = 24;
              else
                word_cnt = word_cnt + 4;// - 4;
              // decrement nibble counter
              nibble_cnt = nibble_cnt - 1;
              // wait for delta time
              delta_t = !delta_t;
           end // while
         #1;
      end
   endtask // paralel_crc_phy_rx
 
 
 
 

Line No.	Rev	Author	Line
1	408	julius	`//////////////////////////////////////////////////////////////////////`
2			`//// ////`
3			`//// Ethernet MAC Stimulus ////`
4			`//// ////`
5			`//// Description ////`
6			`//// Ethernet MAC stimulus tasks. Taken from the project ////`
7			`//// testbench in the ethmac core. ////`
8			`//// ////`
9			`//// To Do: ////`
10			`//// ////`
11			`//// ////`
12			`//// Author(s): ////`
13			`//// - Tadej Markovic, tadej@opencores.org ////`
14			`//// - Igor Mohor, igorM@opencores.org ////`
15			`//// - Julius Baxter julius.baxter@orsoc.se ////`
16			`//// ////`
17			`//// ////`
18			`//////////////////////////////////////////////////////////////////////`
19			`//// ////`
20			`//// Copyright (C) 2009 Authors and OPENCORES.ORG ////`
21			`//// ////`
22			`//// This source file may be used and distributed without ////`
23			`//// restriction provided that this copyright statement is not ////`
24			`//// removed from the file and that any derivative work contains ////`
25			`//// the original copyright notice and the associated disclaimer. ////`
26			`//// ////`
27			`//// This source file is free software; you can redistribute it ////`
28			`//// and/or modify it under the terms of the GNU Lesser General ////`
29			`//// Public License as published by the Free Software Foundation; ////`
30			`//// either version 2.1 of the License, or (at your option) any ////`
31			`//// later version. ////`
32			`//// ////`
33			`//// This source is distributed in the hope that it will be ////`
34			`//// useful, but WITHOUT ANY WARRANTY; without even the implied ////`
35			`//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR ////`
36			`//// PURPOSE. See the GNU Lesser General Public License for more ////`
37			`//// details. ////`
38			`//// ////`
39			`//// You should have received a copy of the GNU Lesser General ////`
40			`//// Public License along with this source; if not, download it ////`
41			`//// from http://www.opencores.org/lgpl.shtml ////`
42			`//// ////`
43			`//////////////////////////////////////////////////////////////////////`
44			`define TIME $display("Time: %0t", $time)
45
46			`// Defines for ethernet test to trigger sending/receiving`
47			`// Is straight forward when using RTL design, but if using netlist then paths to`
48			`// the RX/TX enabled bits depend on synthesis tool, etc, but ones here appear to`
49			`// work with design put through Synplify, with hierarchy maintained.`
50	409	julius	`define ETH_TOP dut.ethmac0
51	408	julius	`define ETH_BD_RAM_PATH `ETH_TOP.wishbone.bd_ram
52			`define ETH_MODER_PATH `ETH_TOP.ethreg1.MODER_0
53
54			`ifdef RTL_SIM
55	411	julius	`ifdef ethmac_IS_GATELEVEL
56	408	julius	`define ETH_MODER_TXEN_BIT `ETH_MODER_PATH.r_TxEn;
57			`define ETH_MODER_RXEN_BIT `ETH_MODER_PATH.r_RxEn;
58			`else
59			`define ETH_MODER_TXEN_BIT `ETH_MODER_PATH.DataOut[1];
60			`define ETH_MODER_RXEN_BIT `ETH_MODER_PATH.DataOut[0];
61			`endif
62			`endif
63
64			`ifdef GATE_SIM
65			`define ETH_MODER_TXEN_BIT `ETH_MODER_PATH.r_TxEn;
66			`define ETH_MODER_RXEN_BIT `ETH_MODER_PATH.r_RxEn;
67			`endif
68
69			`reg [15:0] eth_stim_rx_packet_length;`
70			`reg [7:0] st_data;`
71			`reg [31:0] lfsr;`
72			`integer lfsr_last_byte;`
73
74			`// Is number of ethernet packets to send if doing the eth-rx test.`
75	411	julius	`parameter eth_stim_num_rx_only_num_packets = 500; // Set to 0 for continuous RX`
76			`parameter eth_stim_num_rx_only_packet_size = 512;`
77			`parameter eth_stim_num_rx_only_packet_size_change = 2'b01; // 2'b01: Increment`
78			`parameter eth_stim_num_rx_only_packet_size_change_amount = 1;`
79			`parameter eth_stim_num_rx_only_IPG = 800000; // ns`
80	408	julius
81	411	julius	`// Do call/response test`
82			`reg eth_stim_do_rx_reponse_to_tx;`
83
84	408	julius
85			`parameter num_tx_bds = 16;`
86			`parameter num_tx_bds_mask = 4'hf;`
87			`parameter num_rx_bds = 16;`
88			`parameter num_rx_bds_mask = 4'hf;`
89			`parameter max_eth_packet_size = 16'h0600;`
90	411	julius
91	408	julius	`// If running eth-rxtxbig test (sending and receiving maximum packets), then`
92			`// set this parameter to the max packet size, otherwise min packet size`
93			`//parameter rx_while_tx_min_packet_size = max_eth_packet_size;`
94			`parameter rx_while_tx_min_packet_size = 32;`
95
96			`// Use the smallest possible IPG`
97			`parameter eth_stim_use_min_IPG = 0;`
98			`parameter eth_stim_IPG_delay_max = 500_000; // Maximum 500uS ga`
99			`//parameter eth_stim_IPG_delay_max = 100_000_000; // Maximum 100mS between packets`
100			`parameter eth_stim_IPG_min_10mb = 9600; // 9.6 uS`
101			`parameter eth_stim_IPG_min_100mb = 800; // 860+~100 = 960 nS 100MBit min IPG`
102			`parameter eth_stim_check_rx_packet_contents = 1;`
103			`parameter eth_stim_check_tx_packet_contents = 1;`
104
105			`parameter eth_inject_errors = 0;`
106
107			`// When running simulations where you don't want to feed packets to the design`
108			`// like this...`
109			`parameter eth_stim_disable_rx_stim = 0;`
110
111			`// Delay between seeing that the buffer descriptor for an RX packet says it's`
112			`// been received and ending up in the memory.`
113			`// For 25MHz sdram controller, use following:`
114			//parameter Td_rx_packet_check = (`BOARD_CLOCK_PERIOD * 2000);
115			`// For 64MHz sdram controller, use following:`
116			parameter Td_rx_packet_check = (`BOARD_CLOCK_PERIOD * 500);
117
118
119
120			`integer expected_rxbd;// init to 0`
121			`integer expected_txbd;`
122
123			`wire ethmac_rxen;`
124			`wire ethmac_txen;`
125			assign ethmac_rxen = eth_stim_disable_rx_stim ? 0 : `ETH_MODER_RXEN_BIT;
126			assign ethmac_txen = `ETH_MODER_TXEN_BIT;
127
128			`integer eth_rx_num_packets_sent = 0;`
129			`integer eth_rx_num_packets_checked = 0;`
130			`integer num_tx_packets = 1;`
131
132			`integer rx_packet_lengths [0:1023]; // Array of packet lengths`
133
134
135			`integer speed_loop;`
136
137			`// When txen is (re)enabled, the tx bd pointer goes back to 0`
138			`always @(posedge ethmac_txen)`
139			`expected_txbd = 0;`
140
141			`reg eth_stim_waiting;`
142
143			`initial`
144			`begin`
145			`#1;`
146			`//lfsr = 32'h84218421; // Init pseudo lfsr`
147			`lfsr = 32'h00700001; // Init pseudo lfsr`
148			`lfsr_last_byte = 0;`
149
150			`eth_stim_waiting = 1;`
151	411	julius	`expected_rxbd = num_tx_bds; // init this here`
152
153			`eth_stim_do_rx_reponse_to_tx = 0;`
154	408	julius
155	411	julius
156	408	julius	`while (eth_stim_waiting) // Loop, waiting for enabling of MAC by software`
157			`begin`
158			`#100;`
159			`// If RX enable and not TX enable...`
160			`if(ethmac_rxen === 1'b1 & !(ethmac_txen===1'b1))`
161			`begin`
162			`if (eth_inject_errors)`
163			`begin`
164	411	julius	`do_rx_only_stim(16, 64, 0, 0);`
165			`do_rx_only_stim(128, 64, 1'b1, 8);`
166			`do_rx_only_stim(256, 64, 1'b1, 4);`
167	408	julius	`eth_stim_waiting = 0;`
168			`end`
169			`else`
170			`begin`
171	411	julius	`//do_rx_only_stim(eth_stim_num_rx_only_num_packets,`
172			`//eth_stim_num_rx_only_packet_size, 0, 0);`
173
174			`// Call packet send loop directly. No error injection.`
175			`send_packet_loop(eth_stim_num_rx_only_num_packets,`
176			`eth_stim_num_rx_only_packet_size,`
177			`eth_stim_num_rx_only_packet_size_change,`
178			`eth_stim_num_rx_only_packet_size_change_amount,`
179			`eth_phy0.eth_speed, // Speed`
180			`eth_stim_num_rx_only_IPG, // IPG`
181			`48'h0012_3456_789a, 48'h0708_090A_0B0C, 1,`
182			`0, 0);`
183
184	408	julius	`eth_stim_waiting = 0;`
185			`end`
186			`end // if (ethmac_rxen === 1'b1 & !(ethmac_txen===1'b1))`
187			`// If both RX and TX enabled`
188			`else if (ethmac_rxen === 1'b1 & ethmac_txen===1'b1)`
189			`begin`
190	411	julius	`// Both enabled - let's wait for the first packet transmitted`
191			`// to see what stimulus we should provide`
192			`while (num_tx_packets==1)`
193			`#1000;`
194
195			`$display("* ethmac RX/TX test request: %x", eth_phy0.tx_mem[0]);`
196
197			`// Check the first received byte's value`
198			`case (eth_phy0.tx_mem[0])`
199			`0:`
200			`begin`
201			`// kickoff call/response here`
202			`eth_stim_do_rx_reponse_to_tx = 1;`
203			`end`
204			`default:`
205			`begin`
206			`do_rx_while_tx_stim(1400);`
207			`end`
208			`endcase // case (eth_phy0.tx_mem[0])`
209
210	408	julius	`eth_stim_waiting = 0;`
211			`end`
212			`end // while (eth_stim_waiting)`
213
214			`end // initial begin`
215
216			`// Main Ethernet RX testing stimulus task.`
217			`// Sends a set of packets at both speeds`
218			`task do_rx_only_stim;`
219			`input [31:0] num_packets;`
220	411	julius	`input [31:0] start_packet_size;`
221	408	julius	`input inject_errors;`
222			`input [31:0] inject_errors_mod;`
223
224			`begin`
225
226			`for(speed_loop=1;speed_loop<3;speed_loop=speed_loop+1)`
227			`begin`
228
229	411	julius	`send_packet_loop(num_packets, start_packet_size, 2'b01, 1,`
230			`speed_loop[0], 10000,`
231	408	julius	`48'h0012_3456_789a, 48'h0708_090A_0B0C, 1,`
232			`inject_errors, inject_errors_mod);`
233
234			`end`
235
236			`end`
237			`endtask // do_rx_stim`
238
239			`// Generate RX packets while there's TX going on`
240			`// Sends a set of packets at both speeds`
241			`task do_rx_while_tx_stim;`
242			`input [31:0] num_packets;`
243			`reg [31:0] IPG; // Inter-packet gap`
244			`reg [31:0] packet_size;`
245
246			`integer j;`
247			`begin`
248
249			`for(j=0;j<num_packets;j=j+1)`
250			`begin`
251			`// Determine delay between RX packets:`
252
253			`if (eth_stim_use_min_IPG)`
254			`begin`
255			`// Assign based on whether we're in 100mbit or 10mbit mode`
256			`IPG = eth_phy0.eth_speed ? eth_stim_IPG_min_100mb :`
257			`eth_stim_IPG_min_10mb;`
258			`// Add a little bit of variability`
259			`// Add up to 15`
260			`IPG = IPG + ($random & 32'h000000f);`
261			`end`
262			`else`
263			`begin`
264			`IPG = $random;`
265
266			`while (IPG > eth_stim_IPG_delay_max)`
267			`IPG = IPG / 2;`
268
269
270			`end`
271			`$display("do_rx_while_tx IPG = %0d", IPG);`
272			`// Determine size of next packet:`
273			`if (rx_while_tx_min_packet_size == max_eth_packet_size)`
274			`// We want to transmit biggest packets possible, easy case`
275			`packet_size = max_eth_packet_size - 4;`
276			`else`
277			`begin`
278			`// Constrained random sized packets`
279			`packet_size = $random;`
280
281			`while (packet_size > (max_eth_packet_size-4))`
282			`packet_size = packet_size / 2;`
283
284			`// Now divide by least significant bits of j`
285			`packet_size = packet_size / {29'd0,j[1:0],1'b1};`
286			`if (packet_size < 60)`
287			`packet_size = packet_size + 60;`
288			`end`
289
290			`$display("do_rx_while_tx packet_size = %0d", packet_size);`
291			`send_packet_loop(1, packet_size, 2'b01, 1, eth_phy0.eth_speed,`
292			`IPG, 48'h0012_3456_789a,`
293			`48'h0708_090A_0B0C, 1, 1'b0, 0);`
294
295			`// If RX enable went low, wait for it go high again`
296			`if (ethmac_rxen===1'b0)`
297			`begin`
298
299			`while (ethmac_rxen===1'b0)`
300			`begin`
301			`@(posedge ethmac_rxen);`
302			`#10000;`
303			`end`
304
305			`// RX disabled and when re-enabled we reset the buffer descriptor number`
306			`expected_rxbd = num_tx_bds;`
307
308			`end`
309
310			`end // for (j=0;j<num_packets;j=j+1)`
311			`end`
312			`endtask // do_rx_stim`
313
314	411	julius	`// Registers used in detecting transmitted packets`
315			`reg eth_stim_tx_loop_keep_polling;`
316			`reg [31:0] ethmac_txbd_lenstat, ethmac_last_txbd_lenstat;`
317			`reg eth_stim_detected_packet_tx;`
318
319			`// If in call-response mode, whenever we receive a TX packet, we generate`
320			`// one and send it back`
321			`always @(negedge eth_stim_detected_packet_tx)`
322			`begin`
323			`if (eth_stim_do_rx_reponse_to_tx & ethmac_rxen)`
324			`// Continue if we are enabled`
325			`do_rx_response_to_tx();`
326			`end`
327
328			`// Generate RX packet in rsponse to TX packet`
329			`task do_rx_response_to_tx;`
330			`//input unused;`
331
332			`reg [31:0] IPG; // Inter-packet gap`
333			`reg [31:0] packet_size;`
334
335			`integer j;`
336			`begin`
337
338			`// Get packet size test wants us to send`
339			`packet_size = {eth_phy0.tx_mem[0],eth_phy0.tx_mem[1],`
340			`eth_phy0.tx_mem[2],eth_phy0.tx_mem[3]};`
341
342
343			`IPG = {eth_phy0.tx_mem[4],eth_phy0.tx_mem[5],`
344			`eth_phy0.tx_mem[6],eth_phy0.tx_mem[7]};`
345
346
347			`$display("do_rx_response_to_tx IPG = %0d", IPG);`
348			`if (packet_size == 0)`
349			`begin`
350			`// Constrained random sized packets`
351			`packet_size = $random;`
352
353			`while (packet_size > (max_eth_packet_size-4))`
354			`packet_size = packet_size / 2;`
355
356			`if (packet_size < 60)`
357			`packet_size = packet_size + 60;`
358			`end`
359
360			`$display("do_rx_response_to_tx packet_size = %0d", packet_size);`
361			`send_packet_loop(1, packet_size, 2'b01, 1, eth_phy0.eth_speed,`
362			`IPG, 48'h0012_3456_789a,`
363			`48'h0708_090A_0B0C, 1, 1'b0, 0);`
364
365			`// If RX enable went low, wait for it go high again`
366			`if (ethmac_rxen===1'b0)`
367			`begin`
368
369			`while (ethmac_rxen===1'b0)`
370			`begin`
371			`@(posedge ethmac_rxen);`
372			`#10000;`
373			`end`
374
375			`// RX disabled and when re-enabled we reset the buffer`
376			`// descriptor number`
377			`expected_rxbd = num_tx_bds;`
378
379			`end`
380
381			`end`
382			`endtask // do_rx_response_to_tx`
383
384
385
386
387
388	408	julius	`//`
389			`// always@() to check the TX buffer descriptors`
390			`//`
391			`always @(posedge ethmac_txen)`
392			`begin`
393	411	julius	`ethmac_last_txbd_lenstat = 0;`
394			`eth_stim_tx_loop_keep_polling=1;`
395	408	julius	`// Wait on the TxBD Ready bit`
396	411	julius	`while(eth_stim_tx_loop_keep_polling)`
397	408	julius	`begin`
398			`#10;`
399	411	julius	`get_bd_lenstat(expected_txbd, ethmac_txbd_lenstat);`
400	408	julius	`// Check if we've finished transmitting this BD`
401	411	julius	`if (!ethmac_txbd_lenstat[15] & ethmac_last_txbd_lenstat[15])`
402	408	julius	`// Falling edge of TX BD Ready`
403	411	julius	`eth_stim_detected_packet_tx = 1;`
404	408	julius
405	411	julius	`ethmac_last_txbd_lenstat = ethmac_txbd_lenstat;`
406	408	julius
407			`// If TX en goes low then exit`
408			`if (!ethmac_txen)`
409	411	julius	`eth_stim_tx_loop_keep_polling = 0;`
410			`else if (eth_stim_detected_packet_tx)`
411	408	julius	`begin`
412			`// Wait until the eth_phy has finished receiving it`
413			`while (eth_phy0.mtxen_i === 1'b1)`
414			`#10;`
415
416			`$display("(%t) Check TX packet: bd %d: 0x%h",$time,`
417	411	julius	`expected_txbd, ethmac_txbd_lenstat);`
418	408	julius
419			`// Check the TXBD, see if the packet transmitted OK`
420	411	julius	`if (ethmac_txbd_lenstat[8] \| ethmac_txbd_lenstat[3])`
421	408	julius	`begin`
422			`// Error occured`
423			`TIME;
424			`$display("*E TX Error of packet %0d detected.",`
425			`num_tx_packets);`
426			`$display(" TX BD %0d = 0x%h", expected_txbd,`
427	411	julius	`ethmac_txbd_lenstat);`
428			`if (ethmac_txbd_lenstat[8])`
429	408	julius	`$display(" Underrun in MAC during TX");`
430	411	julius	`if (ethmac_txbd_lenstat[3])`
431	408	julius	`$display(" Retransmission limit hit");`
432
433			`$finish;`
434			`end`
435			`else`
436			`begin`
437	411	julius	`// Packet was OK, let's compare the contents we`
438			`// received with those that were meant to be transmitted`
439	408	julius	`if (eth_stim_check_tx_packet_contents)`
440			`begin`
441			`check_tx_packet(expected_txbd);`
442			`expected_txbd = (expected_txbd + 1) &`
443			`num_tx_bds_mask;`
444			`num_tx_packets = num_tx_packets + 1;`
445	411	julius	`eth_stim_detected_packet_tx = 0;`
446	408	julius	`end`
447			`end`
448			`end`
449	411	julius	`end // while (eth_stim_tx_loop_keep_polling)`
450	408	julius	`end // always @ (posedge ethmac_txen)`
451
452
453
454			`//`
455			`// Check packet TX'd by MAC was good`
456			`//`
457			`task check_tx_packet;`
458			`input [31:0] tx_bd_num;`
459
460			`reg [31:0] tx_bd_addr;`
461			`reg [7:0] phy_byte;`
462
463			`reg [31:0] txpnt_wb; // Pointer in array to where data should be`
464	411	julius	`reg [24:0] txpnt_sdram; // Index in array of shorts for data in SDRAM`
465			`// part`
466	408	julius	`reg [21:0] buffer;`
467			`reg [7:0] sdram_byte;`
468			`reg [31:0] tx_len_bd;`
469
470			`integer i;`
471			`integer failure;`
472			`begin`
473			`failure = 0;`
474
475			`get_bd_lenstat(tx_bd_num, tx_len_bd);`
476
477			`tx_len_bd = {15'd0,tx_len_bd[31:16]};`
478
479			`// Check, if length didn't have to be padded, that`
480			`// amount transmitted was correct`
481			`if ((tx_len_bd > 60)&(tx_len_bd != (eth_phy0.tx_len-4)))`
482			`begin`
483			`$display("*E TX packet sent length, %0d != length in TX BD, %0d",`
484			`eth_phy0.tx_len-4, tx_len_bd);`
485			`#100;`
486			`$finish;`
487			`end`
488
489			`get_bd_addr(tx_bd_num, tx_bd_addr);`
490
491			`// We're never going to be using more than about 256K of receive buffer`
492			`// so let's lop off the top bit of the address pointer - we only want`
493			`// the offset from the base of the memory bank`
494			`txpnt_wb = {14'd0,tx_bd_addr[17:0]};`
495			`txpnt_sdram = tx_bd_addr[24:0];`
496
497			`// Variable we'll use for index in the PHY's TX buffer`
498			`buffer = 0; // Start of TX data`
499			`ifdef VERSATILE_SDRAM
500			`for (i=0;i<tx_len_bd;i=i+1)`

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[/] [openrisc/] [trunk/] [orpsocv2/] [boards/] [actel/] [ordb1a3pe1500/] [bench/] [verilog/] [include/] [eth_stim.v] - Blame information for rev 411