/*
 ########################################################################
 EPIPHANY eLink RX Protocol block
 ########################################################################
 
 This block takes the parallel output of the input deserializers, locates
 valid frame transitions, and decodes the bytes into standard eMesh 
 protocol (104-bit transactions).
 */

module erx_protocol (/*AUTOARG*/
   // Outputs
   erx_access, erx_packet, remap_bypass,
   // Inputs
   reset, rx_enable, clk, rx_packet, rx_burst, rx_access
   );

   parameter AW   = 32;
   parameter DW   = 32;
   parameter PW   = 104;
   parameter ID   = 0;

   
   // System reset input
   input           reset;
   input 	   rx_enable;//Enables receiver

   // Parallel interface, 8 eLink bytes at a time
   input           clk;
   input [PW-1:0]  rx_packet;
   input 	   rx_burst;
   input 	   rx_access;
   
   // Output to MMU / filter
   output          erx_access;
   output [PW-1:0] erx_packet;
   output 	   remap_bypass;    //needed for remapping logic

   reg [31:0] 	   dstaddr_reg;   
   wire [31:0] 	   dstaddr_next;
   wire [31:0] 	   dstaddr_mux;
   reg 		   erx_access;
   reg [PW-1:0]    erx_packet;
   
   //Address generator for bursting
   always @ (posedge clk)
     if(rx_access)
       dstaddr_reg[31:0]     <= dstaddr_mux[31:0];

   assign dstaddr_next[31:0] = dstaddr_reg[31:0] + 4'b1000;
   
   assign dstaddr_mux[31:0] =  rx_burst ? dstaddr_next[31:0] :
			                  rx_packet[39:8];
      
   //Pipeline stage
   always @ (posedge clk)
     begin
	erx_access          <= rx_access;      
	erx_packet[PW-1:0]  <= {rx_packet[PW-1:40],
				 dstaddr_mux[31:0],
				 rx_packet[7:0]
			      };
     end
  
endmodule // erx_protocol
// Local Variables:
// verilog-library-directories:("." "../../common/hdl")
// End:

/*
  Copyright (C) 2015 Adapteva, Inc.
  Contributed by Andreas Olofsson <andreas@adapteva.com>

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  This program 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 General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program (see the file COPYING).  If not, see
  <http://www.gnu.org/licenses/>.
*/