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/*********************************************************************

  SDRAM Controller Core File

  This file is part of the sdram controller project

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

  Description: SDRAM Controller Core Module

    2 types of SDRAMs are supported, 1Mx16 2 bank, or 4Mx16 4 bank.

    This block integrate following sub modules

    sdrc_bs_convert

        convert the system side 32 bit into equvailent 8/16/32 SDR format

    sdrc_req_gen

        This module takes requests from the app, chops them to burst booundaries

        if wrap=0, decodes the bank and passe the request to bank_ctl

   sdrc_xfr_ctl

      This module takes requests from sdr_bank_ctl, runs the transfer and

      controls data flow to/from the app. At the end of the transfer it issues a

      burst terminate if not at the end of a burst and another command to this

      bank is not available.

   sdrc_bank_ctl

      This module takes requests from sdr_req_gen, checks for page hit/miss and

      issues precharge/activate commands and then passes the request to

      sdr_xfr_ctl.

  Assumption: SDRAM Pads should be placed near to this module. else

  user should add a FF near the pads

  To Do:

    nothing

  Author(s):

      - Dinesh Annayya, dinesha@opencores.org

  Version  : 0.0 - 8th Jan 2012

                Initial version with 16/32 Bit SDRAM Support

           : 0.1 - 24th Jan 2012

                 8 Bit SDRAM Support is added

             0.2 - 2nd Feb 2012

                   Improved the command pipe structure to accept up-to

                   4 command of different bank.

             0.3 - 7th Feb 2012

                   Bug fix for parameter defination for request length has changed from 9 to 12

 Copyright (C) 2000 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

*******************************************************************/

`include "sdrc_define.v"

module sdrc_core

           (

                clk,

                pad_clk,

                reset_n,

                sdr_width,

                cfg_colbits,

                /* Request from app */

                app_req,                // Transfer Request

                app_req_addr,           // SDRAM Address

                app_req_len,            // Burst Length (in 16 bit words)

                app_req_wrap,           // Wrap mode request (xfr_len = 4)

                app_req_wr_n,           // 0 => Write request, 1 => read req

                app_req_ack,            // Request has been accepted

                cfg_req_depth,          //how many req. buffer should hold

                app_wr_data,

                app_wr_en_n,

                app_last_wr,

                app_rd_data,

                app_rd_valid,

                app_last_rd,

                app_wr_next_req,

                sdr_init_done,

                app_req_dma_last,

                /* Interface to SDRAMs */

                sdr_cs_n,

                sdr_cke,

                sdr_ras_n,

                sdr_cas_n,

                sdr_we_n,

                sdr_dqm,

                sdr_ba,

                sdr_addr,

                pad_sdr_din,

                sdr_dout,

                sdr_den_n,

                /* Parameters */

                cfg_sdr_en,

                cfg_sdr_mode_reg,

                cfg_sdr_tras_d,

                cfg_sdr_trp_d,

                cfg_sdr_trcd_d,

                cfg_sdr_cas,

                cfg_sdr_trcar_d,

                cfg_sdr_twr_d,

                cfg_sdr_rfsh,

                cfg_sdr_rfmax);

parameter  APP_AW   = 30;  // Application Address Width

parameter  APP_DW   = 32;  // Application Data Width 

parameter  APP_BW   = 4;   // Application Byte Width

parameter  APP_RW   = 9;   // Application Request Width

parameter  SDR_DW   = 16;  // SDR Data Width 

parameter  SDR_BW   = 2;   // SDR Byte Width

// 12 bit subtractor is not feasibile for FPGA, so changed to 8 bits

parameter  REQ_BW   = (`TARGET_DESIGN == `FPGA) ? 8 : 12;   //  Request Width

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

// Global Variable

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

input                   clk                 ; // SDRAM Clock 

input                   pad_clk             ; // SDRAM Clock from Pad, used for registering Read Data

input                   reset_n             ; // Reset Signal

input [1:0]             sdr_width           ; // 2'b00 - 32 Bit SDR, 2'b01 - 16 Bit SDR, 2'b1x - 8 Bit

input [1:0]             cfg_colbits         ; // 2'b00 - 8 Bit column address, 2'b01 - 9 Bit, 10 - 10 bit, 11 - 11Bits

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

// Request from app

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

input                   app_req             ; // Application Request

input [APP_AW-1:0]       app_req_addr        ; // Address 

input                   app_req_wr_n        ; // 0 - Write, 1 - Read

input                   app_req_wrap        ; // Address Wrap

output                  app_req_ack         ; // Application Request Ack

input [APP_DW-1:0]       app_wr_data         ; // Write Data

output                  app_wr_next_req     ; // Next Write Data Request

input [APP_BW-1:0]       app_wr_en_n         ; // Byte wise Write Enable

output                  app_last_wr         ; // Last Write trannsfer of a given Burst

output [APP_DW-1:0]      app_rd_data         ; // Read Data

output                  app_rd_valid        ; // Read Valid

output                  app_last_rd         ; // Last Read Transfer of a given Burst

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

// Interface to SDRAMs

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

output                  sdr_cke             ; // SDRAM CKE

output                  sdr_cs_n            ; // SDRAM Chip Select

output                  sdr_ras_n           ; // SDRAM ras

output                  sdr_cas_n           ; // SDRAM cas

output                  sdr_we_n            ; // SDRAM write enable

output [SDR_BW-1:0]      sdr_dqm             ; // SDRAM Data Mask

output [1:0]             sdr_ba              ; // SDRAM Bank Enable

output [11:0]            sdr_addr            ; // SDRAM Address

input [SDR_DW-1:0]       pad_sdr_din         ; // SDRA Data Input

output [SDR_DW-1:0]      sdr_dout            ; // SDRAM Data Output

output [SDR_BW-1:0]      sdr_den_n           ; // SDRAM Data Output enable

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

// Configuration Parameter

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

output                  sdr_init_done       ; // Indicate SDRAM Initialisation Done

input [3:0]              cfg_sdr_tras_d      ; // Active to precharge delay

input [3:0]             cfg_sdr_trp_d       ; // Precharge to active delay

input [3:0]             cfg_sdr_trcd_d      ; // Active to R/W delay

input                   cfg_sdr_en          ; // Enable SDRAM controller

input [1:0]              cfg_req_depth       ; // Maximum Request accepted by SDRAM controller

input [APP_RW-1:0]       app_req_len         ; // Application Burst Request length in 32 bit 

input [11:0]             cfg_sdr_mode_reg    ;

input [2:0]              cfg_sdr_cas         ; // SDRAM CAS Latency

input [3:0]              cfg_sdr_trcar_d     ; // Auto-refresh period

input [3:0]             cfg_sdr_twr_d       ; // Write recovery delay

input [`SDR_RFSH_TIMER_W-1 : 0] cfg_sdr_rfsh;

input [`SDR_RFSH_ROW_CNT_W -1 : 0] cfg_sdr_rfmax;

input                   app_req_dma_last;    // this signal should close the bank

/****************************************************************************/

// Internal Nets

// SDR_REQ_GEN

wire [`SDR_REQ_ID_W-1:0]r2b_req_id;

wire [1:0]               r2b_ba;

wire [11:0]              r2b_raddr;

wire [11:0]              r2b_caddr;

wire [REQ_BW-1:0]        r2b_len;

// SDR BANK CTL

wire [`SDR_REQ_ID_W-1:0]b2x_id;

wire [1:0]               b2x_ba;

wire [11:0]              b2x_addr;

wire [REQ_BW-1:0]        b2x_len;

wire [1:0]               b2x_cmd;

// SDR_XFR_CTL

wire [3:0]               x2b_pre_ok;

wire [`SDR_REQ_ID_W-1:0]xfr_id;

wire [APP_DW-1:0]        app_rd_data;

wire                    sdr_cs_n, sdr_cke, sdr_ras_n, sdr_cas_n, sdr_we_n;

wire [SDR_BW-1:0]        sdr_dqm;

wire [1:0]               sdr_ba;

wire [11:0]              sdr_addr;

wire [SDR_DW-1:0]        sdr_dout;

wire [SDR_DW-1:0]        sdr_dout_int;

wire [SDR_BW-1:0]        sdr_den_n;

wire [SDR_BW-1:0]        sdr_den_n_int;

wire [1:0]               xfr_bank_sel;

wire [APP_AW-1:0]        app_req_addr;

wire [APP_RW-1:0]        app_req_len;

wire [APP_DW-1:0]        app_wr_data;

wire [SDR_DW-1:0]        a2x_wrdt       ;

wire [APP_BW-1:0]        app_wr_en_n;

wire [SDR_BW-1:0]        a2x_wren_n;

//wire [31:0] app_rd_data;

wire [SDR_DW-1:0]        x2a_rddt;

// synopsys translate_off 

   wire [3:0]           sdr_cmd;

   assign sdr_cmd = {sdr_cs_n, sdr_ras_n, sdr_cas_n, sdr_we_n};

// synopsys translate_on 

assign sdr_den_n = sdr_den_n_int ;

assign sdr_dout  = sdr_dout_int ;

// To meet the timing at read path, read data is registered w.r.t pad_sdram_clock and register back to sdram_clk

// assumption, pad_sdram_clk is synhronous and delayed clock of sdram_clk.

// register w.r.t pad sdram clk

reg [SDR_DW-1:0] pad_sdr_din1;

reg [SDR_DW-1:0] pad_sdr_din2;

always@(posedge pad_clk) begin

   pad_sdr_din1 <= pad_sdr_din;

end

always@(posedge clk) begin

   pad_sdr_din2 <= pad_sdr_din1;

end

   /****************************************************************************/

   // Instantiate sdr_req_gen

   // This module takes requests from the app, chops them to burst booundaries

   // if wrap=0, decodes the bank and passe the request to bank_ctl

sdrc_req_gen #(.SDR_DW(SDR_DW) , .SDR_BW(SDR_BW)) u_req_gen (

          .clk                (clk          ),

          .reset_n            (reset_n            ),

          .cfg_colbits        (cfg_colbits        ),

          .sdr_width          (sdr_width          ),

        /* Req to xfr_ctl */

          .r2x_idle           (r2x_idle           ),

        /* Request from app */

          .req                (app_req            ),

          .req_id             (4'b0               ),

          .req_addr           (app_req_addr       ),

          .req_len            (app_req_len        ),

          .req_wrap           (app_req_wrap       ),

          .req_wr_n           (app_req_wr_n       ),

          .req_ack            (app_req_ack        ),

       /* Req to bank_ctl */

          .r2b_req            (r2b_req            ),

          .r2b_req_id         (r2b_req_id         ),

          .r2b_start          (r2b_start          ),

          .r2b_last           (r2b_last           ),

          .r2b_wrap           (r2b_wrap           ),

          .r2b_ba             (r2b_ba             ),

          .r2b_raddr          (r2b_raddr          ),

          .r2b_caddr          (r2b_caddr          ),

          .r2b_len            (r2b_len            ),

          .r2b_write          (r2b_write          ),

          .b2r_ack            (b2r_ack            ),

          .b2r_arb_ok         (b2r_arb_ok         )

     );

   /****************************************************************************/

   // Instantiate sdr_bank_ctl

   // This module takes requests from sdr_req_gen, checks for page hit/miss and

   // issues precharge/activate commands and then passes the request to

   // sdr_xfr_ctl. 

sdrc_bank_ctl #(.SDR_DW(SDR_DW) ,  .SDR_BW(SDR_BW)) u_bank_ctl (

          .clk                (clk          ),

          .reset_n            (reset_n            ),

          .a2b_req_depth      (cfg_req_depth      ),

      /* Req from req_gen */

          .r2b_req            (r2b_req            ),

          .r2b_req_id         (r2b_req_id         ),

          .r2b_start          (r2b_start          ),

          .r2b_last           (r2b_last           ),

          .r2b_wrap           (r2b_wrap           ),

          .r2b_ba             (r2b_ba             ),

          .r2b_raddr          (r2b_raddr          ),

          .r2b_caddr          (r2b_caddr          ),

          .r2b_len            (r2b_len            ),

          .r2b_write          (r2b_write          ),

          .b2r_arb_ok         (b2r_arb_ok         ),

          .b2r_ack            (b2r_ack            ),

      /* Transfer request to xfr_ctl */

          .b2x_idle           (b2x_idle           ),

          .b2x_req            (b2x_req            ),

          .b2x_start          (b2x_start          ),

          .b2x_last           (b2x_last           ),

          .b2x_wrap           (b2x_wrap           ),

          .b2x_id             (b2x_id             ),

          .b2x_ba             (b2x_ba             ),

          .b2x_addr           (b2x_addr           ),

          .b2x_len            (b2x_len            ),

          .b2x_cmd            (b2x_cmd            ),

          .x2b_ack            (x2b_ack            ),

      /* Status from xfr_ctl */

          .b2x_tras_ok        (b2x_tras_ok        ),

          .x2b_refresh        (x2b_refresh        ),

          .x2b_pre_ok         (x2b_pre_ok         ),

          .x2b_act_ok         (x2b_act_ok         ),

          .x2b_rdok           (x2b_rdok           ),

          .x2b_wrok           (x2b_wrok           ),

      /* for generate cuurent xfr address msb */

          .sdr_req_norm_dma_last(app_req_dma_last),

          .xfr_bank_sel       (xfr_bank_sel       ),

       /* SDRAM Timing */

          .tras_delay         (cfg_sdr_tras_d     ),

          .trp_delay          (cfg_sdr_trp_d      ),

          .trcd_delay         (cfg_sdr_trcd_d     )

      );

   /****************************************************************************/

   // Instantiate sdr_xfr_ctl

   // This module takes requests from sdr_bank_ctl, runs the transfer and

   // controls data flow to/from the app. At the end of the transfer it issues a

   // burst terminate if not at the end of a burst and another command to this

   // bank is not available.

sdrc_xfr_ctl #(.SDR_DW(SDR_DW) ,  .SDR_BW(SDR_BW)) u_xfr_ctl (

          .clk                (clk          ),

          .reset_n            (reset_n            ),

      /* Transfer request from bank_ctl */

          .r2x_idle           (r2x_idle           ),

          .b2x_idle           (b2x_idle           ),

          .b2x_req            (b2x_req            ),

          .b2x_start          (b2x_start          ),

          .b2x_last           (b2x_last           ),

          .b2x_wrap           (b2x_wrap           ),

          .b2x_id             (b2x_id             ),

          .b2x_ba             (b2x_ba             ),

          .b2x_addr           (b2x_addr           ),

          .b2x_len            (b2x_len            ),

          .b2x_cmd            (b2x_cmd            ),

          .x2b_ack            (x2b_ack            ),

       /* Status to bank_ctl, req_gen */

          .b2x_tras_ok        (b2x_tras_ok        ),

          .x2b_refresh        (x2b_refresh        ),

          .x2b_pre_ok         (x2b_pre_ok         ),

          .x2b_act_ok         (x2b_act_ok         ),

          .x2b_rdok           (x2b_rdok           ),

          .x2b_wrok           (x2b_wrok           ),

       /* SDRAM I/O */

          .sdr_cs_n           (sdr_cs_n           ),

          .sdr_cke            (sdr_cke            ),

          .sdr_ras_n          (sdr_ras_n          ),

          .sdr_cas_n          (sdr_cas_n          ),

          .sdr_we_n           (sdr_we_n           ),

          .sdr_dqm            (sdr_dqm            ),

          .sdr_ba             (sdr_ba             ),

          .sdr_addr           (sdr_addr           ),

          .sdr_din            (pad_sdr_din2       ),

          .sdr_dout           (sdr_dout_int       ),

          .sdr_den_n          (sdr_den_n_int      ),

      /* Data Flow to the app */

          .x2a_rdstart        (x2a_rdstart        ),

          .x2a_wrstart        (x2a_wrstart        ),

          .x2a_id             (xfr_id             ),

          .x2a_rdlast         (x2a_rdlast         ),

          .x2a_wrlast         (x2a_wrlast         ),

          .a2x_wrdt           (a2x_wrdt           ),

          .a2x_wren_n         (a2x_wren_n         ),

          .x2a_wrnext         (x2a_wrnext         ),

          .x2a_rddt           (x2a_rddt           ),

          .x2a_rdok           (x2a_rdok           ),

          .sdr_init_done      (sdr_init_done      ),

      /* SDRAM Parameters */

          .sdram_enable       (cfg_sdr_en         ),

          .sdram_mode_reg     (cfg_sdr_mode_reg   ),

      /* current xfr bank */

          .xfr_bank_sel       (xfr_bank_sel       ),

      /* SDRAM Timing */

          .cas_latency        (cfg_sdr_cas        ),

          .trp_delay          (cfg_sdr_trp_d      ),

          .trcar_delay        (cfg_sdr_trcar_d    ),

          .twr_delay          (cfg_sdr_twr_d      ),

          .rfsh_time          (cfg_sdr_rfsh       ),

          .rfsh_rmax          (cfg_sdr_rfmax      )

    );

   /****************************************************************************/

   // Instantiate sdr_bs_convert

   //    This model handle the bus with transaltion from application layer to

   //       8/16/32 SDRAM Memory format

   //     During Write Phase, this block split the data as per SDRAM Width

   //     During Read Phase, This block does the re-packing based on SDRAM

   //     Width

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

sdrc_bs_convert #(.SDR_DW(SDR_DW) ,  .SDR_BW(SDR_BW)) u_bs_convert (

          .clk                (clk          ),

          .reset_n            (reset_n            ),

          .sdr_width          (sdr_width          ),

   /* Control Signal from xfr ctrl */

          // Read Interface Inputs

          .x2a_rdstart        (x2a_rdstart        ),

          .x2a_rdlast         (x2a_rdlast         ),

          .x2a_rdok           (x2a_rdok           ),

          // Read Interface outputs

          .x2a_rddt           (x2a_rddt           ),

          // Write Interface, Inputs

          .x2a_wrstart        (x2a_wrstart        ),

          .x2a_wrlast         (x2a_wrlast         ),

          .x2a_wrnext         (x2a_wrnext         ),

          // Write Interface, Outputs

          .a2x_wrdt           (a2x_wrdt           ),

          .a2x_wren_n         (a2x_wren_n         ),

   /* Control Signal from sdrc_bank_ctl  */

   /*  Control Signal from/to to application i/f  */

          .app_wr_data        (app_wr_data        ),

          .app_wr_en_n        (app_wr_en_n        ),

          .app_wr_next        (app_wr_next_req    ),

          .app_last_wr        (app_last_wr        ),

          .app_rd_data        (app_rd_data        ),

          .app_rd_valid       (app_rd_valid       ),

          .app_last_rd        (app_last_rd        )

       );

endmodule // sdrc_core