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

**      File:  wb_bram_ctrl.v

**

**

**      Copyright (C) 2014-2017  Alireza Monemi

**

**      This file is part of ProNoC

**

**      ProNoC ( stands for Prototype Network-on-chip)  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 of the License, or (at your option) any later version.

**

**      ProNoC 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 ProNoC. If not, see <http:**www.gnu.org/licenses/>.

**

**

**      Description:

**      memory wishbone bus interface controller

**

**

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

`timescale       1ns/1ps

module wb_bram_ctrl #(

    parameter Dw=32, //RAM data_width in bits

    parameter Aw=10, //RAM address width

    // wishbon bus param

    parameter BURST_MODE = "DISABLED", // "DISABLED" , "ENABLED" wisbone bus burst mode 

    parameter SELw = Dw/8,

    parameter CTIw = 3,

    parameter BTEw = 2

)(

    clk,

    reset,

     //wishbone bus interface

    sa_dat_i,

    sa_sel_i,

    sa_addr_i,

    sa_cti_i,

    sa_bte_i,

    sa_stb_i,

    sa_cyc_i,

    sa_we_i,

    sa_dat_o,

    sa_ack_o,

    sa_err_o,

    sa_rty_o,

    // BRAM interface 

    d,

    addr,

    we,

    q

);

    input            clk;

    input            reset;

   // BRAM interface 

    output   [Dw-1   :   0]  d;

    output   [Aw-1   :   0]  addr;

    output                 we;

    input  [Dw-1    :   0]  q;

// Wishbone bus interface

    input       [Dw-1       :   0]      sa_dat_i;

    input       [SELw-1     :   0]      sa_sel_i;

    input       [Aw-1       :   0]      sa_addr_i;

    input                      sa_stb_i;

    input                      sa_cyc_i;

    input                      sa_we_i;

    input       [CTIw-1     :   0]      sa_cti_i;

    input       [BTEw-1     :   0]      sa_bte_i;

    output     [Dw-1       :   0]      sa_dat_o;

    output                    sa_ack_o;

    output                     sa_err_o;

    output                     sa_rty_o;

    wire sa_ack;

    // 3'b100 is reserved in wb4 interface. It is used for ni

   // wire sa_ack_ni_burst =   sa_stb_i ; //the ack is registerd inside the master in burst mode 

  //  assign sa_ack_o = (sa_cti_i == 3'b100 ) ?  sa_ack_ni_burst: sa_ack;

    assign sa_ack_o =  sa_ack;

    generate if (BURST_MODE== "ENABLED") begin : burst_wb

        wb_burst_bram_ctrl #(

                .Dw(Dw),

                .Aw(Aw),

                .SELw(SELw),

                .CTIw(CTIw),

                .BTEw(BTEw)

        )

        bram_ctrl

        (

                .clk(clk),

                .reset(reset),

                .d(d),

                .addr(addr),

                .we(we),

                .q(q),

                .sa_dat_i(sa_dat_i),

                .sa_sel_i(sa_sel_i),

                .sa_addr_i(sa_addr_i),

                .sa_stb_i(sa_stb_i),

                .sa_cyc_i(sa_cyc_i),

                .sa_we_i(sa_we_i),

                .sa_cti_i(sa_cti_i),

            .sa_bte_i(sa_bte_i),

                .sa_dat_o(sa_dat_o),

                .sa_ack_o(sa_ack),

                .sa_err_o(sa_err_o),

                .sa_rty_o(sa_rty_o)

     );

    end else begin : no_burst

     assign sa_dat_o =   q;

     assign d     =   sa_dat_i ;

     assign addr     =   sa_addr_i;

     assign we       =   sa_stb_i &  sa_we_i;

     assign sa_err_o =   1'b0;

     assign sa_rty_o =   1'b0;

     reg ack;

     assign sa_ack = ack;

     always @(posedge clk ) begin

         if(reset) begin

          ack  <= 1'b0;

         end else begin

          ack  <= (~sa_ack_o) & sa_stb_i;

         end

     end

    end

    endgenerate

endmodule

module wb_burst_bram_ctrl #(

        parameter Dw=32, //RAM data_width in bits

        parameter Aw=10, //RAM address width

        // wishbon bus param

        parameter       SELw   = Dw/8,

        parameter       CTIw   = 3,

        parameter   BTEw   = 2

)(

        clk,

        reset,

         //wishbone bus interface

        sa_dat_i,

        sa_sel_i,

        sa_addr_i,

        sa_cti_i,

        sa_bte_i,

        sa_stb_i,

        sa_cyc_i,

        sa_we_i,

        sa_dat_o,

        sa_ack_o,

        sa_err_o,

        sa_rty_o,

        // BRAM interface 

        d,

        addr,

        we,

        q

);

    `define UDLY  1

        input            clk;

        input            reset;

   // BRAM interface 

        output   [Dw-1   :   0]  d;

        output   [Aw-1   :   0]  addr;

        output                                           we;

        input  [Dw-1    :   0]  q;

        // Wishbone bus interface

        input       [Dw-1       :   0]      sa_dat_i;

        input       [SELw-1     :   0]      sa_sel_i;

        input       [Aw-1       :   0]      sa_addr_i;

        input                      sa_stb_i;

        input                      sa_cyc_i;

        input                      sa_we_i;

        input       [CTIw-1     :   0]      sa_cti_i;

        input       [BTEw-1     :   0]      sa_bte_i;

        output  reg   [Dw-1       :   0]      sa_dat_o;

        output  reg                  sa_ack_o;

        output  reg                   sa_err_o;

        output  reg                   sa_rty_o;

    //Burst Type Extension for Incrementing and Decrementing bursts

    localparam [1:0]

        LINEAR  = 2'b00,

        FOUR_BEAT =2'b01,

        EIGHT_BEAT=2'b10,

        SIXTEEN_BEAT =2'b11;

   localparam [2:0] ST_IDLE  = 3'b000,

                        ST_BURST = 3'b001,

                        ST_END   = 3'b010,

                        ST_SUBRD = 3'b100,

                        ST_SUB   = 3'b101,

                        ST_SUBWR = 3'b110;

         /*----------------------------------------------------------------------

          Internal Nets and Registers

          ----------------------------------------------------------------------*/

         wire [Dw-1:0] data;      // Data read from RAM

         reg                     write_enable; // RAM write enable

         reg [Dw-1:0]  write_data, write_data_d;   // RAM write data

         reg [Aw+1:0]  pmi_address,  pmi_address_nxt;

         reg [Aw+1:0]  adr_linear_incr,adr_4_beat,adr_8_beat,adr_16_beat;

         reg [Aw-1:0]  read_address, write_address;

         reg                     sa_ack_o_nxt;

         reg [Dw-1:0]  read_data;

        // reg                   read_enable;

         reg                     raw_hazard, raw_hazard_nxt;

         reg [Dw-1:0]  sa_dat_i_d;

         reg [3:0]                sa_sel_i_d;

         reg                     delayed_write;

         wire [Aw+1 : 0] addr_init = {sa_addr_i,2'b00};

         /*----------------------------------------------------------------------

          State Machine

          ----------------------------------------------------------------------*/

         reg [2:0] state, state_nxt;

         always @(*)

           case (state)

             ST_IDLE:

               if (sa_stb_i && sa_cyc_i && (sa_ack_o == 1'b0))

                 if(sa_cti_i ==3'b100)

                        state_nxt = ST_IDLE;

                 else if ((sa_cti_i == 3'b000) || (sa_cti_i == 3'b111) )

                   state_nxt = ST_END;

                 else

                   if (sa_we_i && (sa_sel_i != 4'b1111))

                     state_nxt = ST_SUBRD;

                   else

                     state_nxt = ST_BURST;

               else

                 state_nxt = state;

             ST_BURST:

               if (sa_cti_i == 3'b111)

                 state_nxt = ST_IDLE;

               else

                 state_nxt = state;

             ST_SUBRD:

               state_nxt = ST_SUB;

             ST_SUB:

               if (sa_cti_i == 3'b111)

                 state_nxt = ST_SUBWR;

               else

                 state_nxt = state;

             default:

               state_nxt = ST_IDLE;

           endcase

         /*----------------------------------------------------------------------

          ----------------------------------------------------------------------*/

         always @(*)

           if ((state == ST_SUB) && (read_address == write_address))

             raw_hazard_nxt = 1'b1;

           else

             raw_hazard_nxt = 1'b0;

         /*----------------------------------------------------------------------

          Set up read to EBR

          ----------------------------------------------------------------------*/

         always @(*)

           begin

           /*

              if ((sa_we_i == 1'b0)

                  || (sa_we_i

                      && (((state == ST_IDLE) && ((sa_cti_i == 3'b000) || (sa_cti_i == 3'b111) || (sa_sel_i != 4'b1111)))

                          || (state == ST_SUBRD)

                          || ((state == ST_SUB) && (raw_hazard_nxt == 1'b0)))))

                read_enable = 1'b1;

              else

                read_enable = 1'b0;

              */

              read_data = raw_hazard ? write_data_d : data;

           end

         /*----------------------------------------------------------------------

          Set up write to EBR

          ----------------------------------------------------------------------*/

         always @(*)

           begin

              if ((sa_we_i

                   && (// Word Burst Write (first write in a sequence)

                       ((state == ST_IDLE)

                        && sa_cyc_i && sa_stb_i && (sa_cti_i != 3'b000) && (sa_cti_i !=3'b100) && (sa_cti_i != 3'b111) && (sa_sel_i == 4'b1111))

                       // Single Write

                       || (state == ST_END)

                       // Burst Write (all writes beyond first write)

                       || (state == ST_BURST)))

                  // Sub-Word Burst Write

                  || ((state == ST_SUB) || (state == ST_SUBWR)))

                write_enable = 1'b1;

              else

                write_enable = 1'b0;

              if ((state == ST_SUBRD) || (state == ST_SUB) || (state == ST_SUBWR))

                delayed_write = 1'b1;

              else

                delayed_write = 1'b0;

              write_data[7:0]   = (delayed_write

                                   ? (sa_sel_i_d[0] ? sa_dat_i_d[7:0] : read_data[7:0])

                                   : (sa_sel_i[0] ? sa_dat_i[7:0] : data[7:0]));

              write_data[15:8]  = (delayed_write

                                   ? (sa_sel_i_d[1] ? sa_dat_i_d[15:8] : read_data[15:8])

                                   : (sa_sel_i[1] ? sa_dat_i[15:8] : data[15:8]));

              write_data[23:16] = (delayed_write

                                   ? (sa_sel_i_d[2] ? sa_dat_i_d[23:16] : read_data[23:16])

                                   : (sa_sel_i[2] ? sa_dat_i[23:16] : data[23:16]));

              write_data[31:24] = (delayed_write

                                   ? (sa_sel_i_d[3] ? sa_dat_i_d[31:24] : read_data[31:24])

                                   : (sa_sel_i[3] ? sa_dat_i[31:24] : data[31:24]));

           end

    /*----------------------------------------------------------------------

        Set up address to EBR

        ----------------------------------------------------------------------*/

        always @(*) begin

        if (// First address of any access is obtained from Wishbone signals

                  (state == ST_IDLE)

                  // Read for a Sub-Word Wishbone Burst Write

                  || (state == ST_SUB)) read_address = sa_addr_i;

        else read_address = pmi_address[Aw+1:2];

        if ((state == ST_SUB) || (state == ST_SUBWR))  write_address = pmi_address[Aw+1:2];

        else write_address = sa_addr_i;

        // Keep track of first address and subsequently increment it by 4

        // bytes on a burst read

            if (sa_we_i) begin

                //pmi_address_nxt = sa_addr_i[Aw+1:0];

            adr_linear_incr= addr_init;

            adr_4_beat= addr_init;

            adr_8_beat= addr_init;

            adr_16_beat=addr_init;

            end else

            if (state == ST_IDLE)

                if ((sa_sel_i == 4'b1000) || (sa_sel_i == 4'b0100) || (sa_sel_i == 4'b0010) || (sa_sel_i == 4'b0001))begin

                            //pmi_address_nxt = sa_addr_i[Aw+1:0] + 1'b1;

                            adr_linear_incr= addr_init + 1'b1;

                    adr_4_beat= {addr_init[Aw+1 :4], addr_init[3:0] + 1'b1};

                    adr_8_beat= {addr_init[Aw+1 :5], addr_init[4:0] + 1'b1};

                    adr_16_beat={addr_init[Aw+1 :6], addr_init[5:0] + 1'b1};

                end else if ((sa_sel_i == 4'b1100) || (sa_sel_i == 4'b0011))begin

                    //pmi_address_nxt = {(sa_addr_i[Aw+1:1] + 1'b1), 1'b0};

                    adr_linear_incr= {(addr_init[Aw+1:1]  + 1'b1), 1'b0};

                    adr_4_beat= {addr_init[Aw+1 :4], {addr_init[3:1] +1'b1},1'b0};

                    adr_8_beat= {addr_init[Aw+1 :5], {addr_init[4:1] +1'b1},1'b0};

                    adr_16_beat={addr_init[Aw+1 :6], {addr_init[5:1] +1'b1},1'b0};

               end else begin

                           //pmi_address_nxt = {(sa_addr_i[Aw+1:2] + 1'b1), 2'b00};

                            adr_linear_incr= {(addr_init[Aw+1:2]  + 1'b1), 2'b00};

                            adr_4_beat= {addr_init[Aw+1 :4], {addr_init[3:2] +1'b1},2'b00};

                    adr_8_beat= {addr_init[Aw+1 :5], {addr_init[4:2] +1'b1},2'b00};

                    adr_16_beat={addr_init[Aw+1 :6], {addr_init[5:2] +1'b1},2'b00};

                       end

                  else

                  if ((sa_sel_i == 4'b1000) || (sa_sel_i == 4'b0100) || (sa_sel_i == 4'b0010) || (sa_sel_i == 4'b0001))begin

                    //pmi_address_nxt_linear_incr = pmi_address + 1'b1;

                    adr_linear_incr= pmi_address + 1'b1;

                    adr_4_beat= {pmi_address[Aw+1 :4], pmi_address[3:0] + 1'b1};

                    adr_8_beat= {pmi_address[Aw+1 :5], pmi_address[4:0] + 1'b1};

                    adr_16_beat={pmi_address[Aw+1 :6], pmi_address[5:0] + 1'b1};

                  end else if ((sa_sel_i == 4'b1100) || (sa_sel_i == 4'b0011)) begin

                       // pmi_address_nxt = {pmi_address[Aw+1:1] + 1'b1), 1'b0};

                        adr_linear_incr= {(pmi_address[Aw+1:1] + 1'b1), 1'b0};

                        adr_4_beat= {pmi_address[Aw+1 :4], {pmi_address[3:1] + 1'b1},1'b0};

                    adr_8_beat= {pmi_address[Aw+1 :5], {pmi_address[4:1] + 1'b1},1'b0};

                    adr_16_beat={pmi_address[Aw+1 :6], {pmi_address[5:1] + 1'b1},1'b0};

                  end else begin

                    //pmi_address_nxt_linear_incr = {(pmi_address[Aw+1:2] + 1'b1), 2'b00};

                    adr_linear_incr= {(pmi_address[Aw+1:2] + 1'b1), 2'b00};

                    adr_4_beat= {pmi_address[Aw+1 :4], {pmi_address[3:2] +1'b1},2'b00};

                    adr_8_beat= {pmi_address[Aw+1 :5], {pmi_address[4:2] +1'b1},2'b00};

                    adr_16_beat={pmi_address[Aw+1 :6], {pmi_address[5:2] +1'b1},2'b00};

                  end

           end

           always @(*)begin

               case(sa_bte_i)

                LINEAR:      pmi_address_nxt = adr_linear_incr;

                FOUR_BEAT:   pmi_address_nxt = adr_4_beat;

                EIGHT_BEAT:  pmi_address_nxt = adr_8_beat;

                SIXTEEN_BEAT:pmi_address_nxt = adr_16_beat;

           endcase

          end

         /*----------------------------------------------------------------------

          Set up outgoing wishbone signals

          ----------------------------------------------------------------------*/

         always @(*)

           begin

              if (((state == ST_IDLE) && sa_cyc_i && sa_stb_i && (sa_ack_o == 1'b0))

                  || (state == ST_BURST)

                  || (state == ST_SUBRD)

                  || (state == ST_SUB))

                sa_ack_o_nxt = 1'b1;

              else

                sa_ack_o_nxt = 1'b0;

              sa_dat_o = data;

              sa_rty_o = 1'b0;

              sa_err_o = 1'b0;

           end

         /*----------------------------------------------------------------------

          Sequential Logic

          ----------------------------------------------------------------------*/

         always @(posedge clk)

           if (reset)

             begin

                sa_ack_o <= #`UDLY 1'b0;

                sa_dat_i_d <= #`UDLY 0;

                sa_sel_i_d <= #`UDLY 0;

                state <= #`UDLY ST_IDLE;

                pmi_address <= #`UDLY 0;

                write_data_d <= #`UDLY 0;

                raw_hazard <= #`UDLY 0;

             end

           else

             begin

                sa_ack_o <= #`UDLY sa_ack_o_nxt;

                sa_dat_i_d <= #`UDLY sa_dat_i;

                sa_sel_i_d <= #`UDLY sa_sel_i;

                state <= #`UDLY state_nxt;

                pmi_address <= #`UDLY pmi_address_nxt;

                write_data_d <= #`UDLY write_data;

                raw_hazard <= #`UDLY raw_hazard_nxt;

             end

        assign d        = write_data;

        assign addr=(write_enable)? write_address : read_address;

        assign we       = write_enable;

        assign data= q;

endmodule