Subversion Repositories robust_axi2ahb

<##//////////////////////////////////////////////////////////////////

////                                                             ////

////  Author: Eyal Hochberg                                      ////

////          eyal@provartec.com                                 ////

////                                                             ////

////  Downloaded from: http://www.opencores.org                  ////

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

////                                                             ////

//// Copyright (C) 2010 Provartec LTD                            ////

//// www.provartec.com                                           ////

//// info@provartec.com                                          ////

////                                                             ////

//// 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.////

////                                                             ////

//// 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. http://www.gnu.org/licenses/lgpl.html              ////

////                                                             ////

//////////////////////////////////////////////////////////////////##>

INCLUDE def_axi2ahb.txt

OUTFILE PREFIX_rd_fifo.v

module  PREFIX_rd_fifo (PORTS);

   parameter              FIFO_LINES = EXPR(2 * 16); //double buffer of max burst

   parameter              RESP_SLVERR = 2'b10;

   input                  clk;

   input                  reset;

   port                   RGROUP_AXI_R;

   input [DATA_BITS-1:0]  HRDATA;

   input                  HREADY;

   input [1:0]            HTRANS;

   input                  HRESP;

   input [ID_BITS-1:0]    cmd_id;

   input                  cmd_err;

   input                  rdata_phase;

   output                 rdata_ready;

   input                  data_last;

   wire                   data_push;

   wire                   data_pop;

   wire                   data_empty;

   wire                   data_full;

   reg                    RVALID;

   reg [LOG2(CMD_DEPTH):0] burst_cnt;

   wire                   axi_last;

   wire                   ahb_last;

   wire [1:0]             cmd_resp;

   assign                 cmd_resp = cmd_err | HRESP ? RESP_SLVERR : 2'b00;

   assign                 rdata_ready = burst_cnt < 'd2;

   assign                 data_push = rdata_phase & HREADY;

   assign                 data_pop = RVALID & RREADY;

   assign                 axi_last = RVALID & RREADY & RLAST;

   assign                 ahb_last = rdata_phase & data_last;

   always @(posedge clk or posedge reset)

     if (reset)

       burst_cnt <= #FFD 'd0;

     else if (axi_last | ahb_last)

       burst_cnt <= #FFD burst_cnt - axi_last + ahb_last;

   prgen_fifo #(DATA_BITS+ID_BITS+2+1, FIFO_LINES)

   data_fifo(

            .clk(clk),

            .reset(reset),

            .push(data_push),

            .pop(data_pop),

            .din({HRDATA,

                  cmd_id,

                  cmd_resp,

                  ahb_last

                  }

                 ),

            .dout({RDATA,

                   RID,

                   RRESP,

                   RLAST

                   }

                  ),

            .empty(data_empty),

            .full(data_full)

            );

   always @(posedge clk or posedge reset)

     if (reset)

       RVALID <= #FFD 1'b0;

     else if (axi_last)

       RVALID <= #FFD 1'b0;

     else if (burst_cnt > 'd0)

       RVALID <= #FFD 1'b1;

     else

       RVALID <= #FFD 1'b0;

endmodule