Subversion Repositories xge_mac

//////////////////////////////////////////////////////////////////////

////                                                              ////

////  File name "rx_dequeue.v"                                    ////

////                                                              ////

////  This file is part of the "10GE MAC" project                 ////

////  http://www.opencores.org/cores/xge_mac/                     ////

////                                                              ////

////  Author(s):                                                  ////

////      - A. Tanguay (antanguay@opencores.org)                  ////

////                                                              ////

//////////////////////////////////////////////////////////////////////

////                                                              ////

//// Copyright (C) 2008 AUTHORS. All rights reserved.             ////

////                                                              ////

//// 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                     ////

////                                                              ////

//////////////////////////////////////////////////////////////////////

`include "defines.v"

module rx_dequeue(/*AUTOARG*/

  // Outputs

  rxdfifo_ren, pkt_rx_data, pkt_rx_val, pkt_rx_sop, pkt_rx_eop,

  pkt_rx_err, pkt_rx_mod, pkt_rx_avail, status_rxdfifo_udflow_tog,

  // Inputs

  clk_156m25, reset_156m25_n, rxdfifo_rdata, rxdfifo_rstatus,

  rxdfifo_rempty, rxdfifo_ralmost_empty, pkt_rx_ren

  );

input         clk_156m25;

input         reset_156m25_n;

input [63:0]  rxdfifo_rdata;

input [7:0]   rxdfifo_rstatus;

input         rxdfifo_rempty;

input         rxdfifo_ralmost_empty;

input         pkt_rx_ren;

output        rxdfifo_ren;

output [63:0] pkt_rx_data;

output        pkt_rx_val;

output        pkt_rx_sop;

output        pkt_rx_eop;

output        pkt_rx_err;

output [2:0]  pkt_rx_mod;

output        pkt_rx_avail;

output        status_rxdfifo_udflow_tog;

/*AUTOREG*/

// Beginning of automatic regs (for this module's undeclared outputs)

reg                     pkt_rx_avail;

reg [63:0]              pkt_rx_data;

reg                     pkt_rx_eop;

reg                     pkt_rx_err;

reg [2:0]               pkt_rx_mod;

reg                     pkt_rx_sop;

reg                     pkt_rx_val;

reg                     status_rxdfifo_udflow_tog;

// End of automatics

reg           end_eop;

/*AUTOWIRE*/

// End eop to force one cycle between packets

assign rxdfifo_ren = !rxdfifo_rempty && pkt_rx_ren && !end_eop;

always @(posedge clk_156m25 or negedge reset_156m25_n) begin

    if (reset_156m25_n == 1'b0) begin

        pkt_rx_avail <= 1'b0;

        pkt_rx_data <= 64'b0;

        pkt_rx_sop <= 1'b0;

        pkt_rx_eop <= 1'b0;

        pkt_rx_err <= 1'b0;

        pkt_rx_mod <= 3'b0;

        pkt_rx_val <= 1'b0;

        end_eop <= 1'b0;

        status_rxdfifo_udflow_tog <= 1'b0;

    end

    else begin

        pkt_rx_avail <= !rxdfifo_ralmost_empty;

        // If eop shows up at the output of the fifo, we drive eop on

        // the bus on the next read. This will be the last read for this

        // packet. The fifo is designed to output data early. On last read,

        // data from next packet will appear at the output of fifo. Modulus

        // of packet length is in lower bits.

        pkt_rx_eop <= rxdfifo_ren && rxdfifo_rstatus[`RXSTATUS_EOP];

        pkt_rx_mod <= {3{rxdfifo_ren & rxdfifo_rstatus[`RXSTATUS_EOP]}} & rxdfifo_rstatus[2:0];

        pkt_rx_val <= rxdfifo_ren;

        if (rxdfifo_ren) begin

            `ifdef BIGENDIAN

            pkt_rx_data <= {rxdfifo_rdata[7:0],

                            rxdfifo_rdata[15:8],

                            rxdfifo_rdata[23:16],

                            rxdfifo_rdata[31:24],

                            rxdfifo_rdata[39:32],

                            rxdfifo_rdata[47:40],

                            rxdfifo_rdata[55:48],

                            rxdfifo_rdata[63:56]};

            `else

            pkt_rx_data <= rxdfifo_rdata;

            `endif

        end

        if (rxdfifo_ren && rxdfifo_rstatus[`RXSTATUS_SOP]) begin

            // SOP indication on first word

            pkt_rx_sop <= 1'b1;

            pkt_rx_err <= 1'b0;

        end

        else begin

            pkt_rx_sop <= 1'b0;

            // Give an error if FIFO is to underflow

            if (rxdfifo_rempty && pkt_rx_ren && !end_eop) begin

                pkt_rx_val <= 1'b1;

                pkt_rx_eop <= 1'b1;

                pkt_rx_err <= 1'b1;

            end

        end

        if (rxdfifo_ren && |(rxdfifo_rstatus[`RXSTATUS_ERR])) begin

            // Status stored in FIFO is propagated to error signal.

            pkt_rx_err <= 1'b1;

        end

        //---

        // EOP indication at the end of the frame. Cleared otherwise.

        if (rxdfifo_ren && rxdfifo_rstatus[`RXSTATUS_EOP]) begin

            end_eop <= 1'b1;

        end

        else if (pkt_rx_ren) begin

            end_eop <= 1'b0;

        end

        //---

        // FIFO errors, used to generate interrupts

        if (rxdfifo_rempty && pkt_rx_ren && !end_eop) begin

            status_rxdfifo_udflow_tog <= ~status_rxdfifo_udflow_tog;

        end

    end

end

endmodule