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//

// Project      : High-Speed SDRAM Controller with adaptive bank management and command pipeline

// 

// Project Nick : HSSDRC

// 

// Version      : 1.0-beta 

//  

// Revision     : $Revision: 1.1 $ 

// 

// Date         : $Date: 2008-03-06 13:52:43 $ 

// 

// Workfile     : hssdrc_addr_path_p1.v

// 

// Description  : coder for translate logical onehot command to sdram command

// 

// HSSDRC is licensed under MIT License

// 

// Copyright (c) 2007-2008, Denis V.Shekhalev (des00@opencores.org) 

// 

// 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.

//

`include "hssdrc_timescale.vh"

`include "hssdrc_define.vh"

module hssdrc_addr_path_p1(

  clk         ,

  reset       ,

  sclr        ,

  //        

  arb_pre_all ,

  arb_refr    ,

  arb_pre     ,

  arb_act     ,

  arb_read    ,

  arb_write   ,

  arb_lmr     ,

  arb_rowa    ,

  arb_cola    ,

  arb_ba      ,

  //

  addr        ,

  ba          ,

  cke         ,

  cs_n        ,

  ras_n       ,

  cas_n       ,

  we_n

  );

  input wire clk;

  input wire reset;

  input wire sclr;

  //-------------------------------------------------------------------------------------------------- 

  // interface from output arbiter 

  //-------------------------------------------------------------------------------------------------- 

  input wire    arb_pre_all  ;

  input wire    arb_refr     ;

  input wire    arb_pre      ;

  input wire    arb_act      ;

  input wire    arb_read     ;

  input wire    arb_write    ;

  input wire    arb_lmr      ;

  input rowa_t  arb_rowa     ;

  input cola_t  arb_cola     ;

  input ba_t    arb_ba       ;

  //-------------------------------------------------------------------------------------------------- 

  // interface to sdram 

  //-------------------------------------------------------------------------------------------------- 

  output  sdram_addr_t  addr;

  output  ba_t          ba;

  output  logic         cke;

  output  logic         cs_n;

  output  logic         ras_n;

  output  logic         cas_n;

  output  logic         we_n;

  //

  //

  // 

  logic [3:0]   cs_n__ras_n__cas_n__we_n;

  sdram_addr_t  addr_latched;

  ba_t          ba_latched;

  //--------------------------------------------------------------------------------------------------  

  //

  //--------------------------------------------------------------------------------------------------  

  always_ff @(posedge clk or posedge reset) begin : logical_command_decode

    if (reset)

      cs_n__ras_n__cas_n__we_n <= 4'b1111; // inheribit nop

    else if (sclr)

      cs_n__ras_n__cas_n__we_n <= 4'b1111; // inheribit nop

    else begin

      unique case (1'b1)

        arb_pre_all  : cs_n__ras_n__cas_n__we_n <= 4'b0010; // Pre

        arb_refr     : cs_n__ras_n__cas_n__we_n <= 4'b0001; // Refr

        arb_pre      : cs_n__ras_n__cas_n__we_n <= 4'b0010; // Pre

        arb_act      : cs_n__ras_n__cas_n__we_n <= 4'b0011; // Act

        arb_write    : cs_n__ras_n__cas_n__we_n <= 4'b0100; // Write

        arb_read     : cs_n__ras_n__cas_n__we_n <= 4'b0101; // Read

        arb_lmr      : cs_n__ras_n__cas_n__we_n <= 4'b0000; // Lmr (data == address) 

        default      : cs_n__ras_n__cas_n__we_n <= 4'b0111;

      endcase

    end

  end

  //

  // don't use clocking disable 

  //

  assign cke = 1'b1;

  // synthesis translate_off 

  initial begin

    {cs_n, ras_n, cas_n, we_n} <= 4'b1111; // only to disable mt48lc2m warnings

  end

  // synthesis translate_on

  always_ff @(posedge clk or posedge reset) begin : sdram_control_register

    if (reset)      {cs_n, ras_n, cas_n, we_n} <= 4'b1111;  // inheribit nop

    else if (sclr)  {cs_n, ras_n, cas_n, we_n} <= 4'b1111;  // inheribit nop

    else            {cs_n, ras_n, cas_n, we_n} <= cs_n__ras_n__cas_n__we_n;

  end

  always_ff @(posedge clk) begin : sdram_mux_addr_path

    ba_latched  <= arb_ba;

    ba          <= ba_latched;

    if (arb_act | arb_lmr)

      addr_latched <= ResizeRowa(arb_rowa);

    else

      addr_latched <= ResizeCola(arb_cola, arb_pre_all);

    addr <= addr_latched;

  end

  //--------------------------------------------------------------------------------------------------  

  // function to get sdram address from row address. row address is transfered during 

  // act/lmr sdram command and is directly mapped to row address.

  //--------------------------------------------------------------------------------------------------  

  function sdram_addr_t ResizeRowa (input rowa_t rowa);

    int i;

    sdram_addr_t addr_resized;

    for (i = 0; i < pSdramAddrBits; i++) begin

      if (pRowaBits > i)

          addr_resized[i] = rowa[i];

        else

          addr_resized[i] = 1'b0;

    end

    return addr_resized;

  endfunction

  //--------------------------------------------------------------------------------------------------  

  // function to get sdram address from column address. column address is transfered during :

  // 1. read/write sdram command and A10 is autoprecharge bit and if pColaBits > 10 then 

  //    cola [$:10] is mapped to addr [$:11]. 

  // 2. pre sdram command and A10 is select all banks bit 

  //--------------------------------------------------------------------------------------------------  

  function sdram_addr_t ResizeCola (input cola_t cola, input bit pre_all);

    int i;

    sdram_addr_t addr_resized;

    for (i = 0; i < pSdramAddrBits; i++) begin

      if (i < 10) begin

        if (pColaBits > i)

          addr_resized[i] = cola[i];

        else

          addr_resized[i] = 1'b0;

      end

      else if (i == 10) begin

        addr_resized[i] = pre_all; // Autoprecharge is not used -> A10 is always 1'b0 then read/write active

      end

      else begin

        if (pColaBits > i)

          addr_resized[i] = cola[i-1];

        else

          addr_resized[i] = 1'b0;

      end

    end

    return addr_resized;

  endfunction

endmodule