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

////                                                              ////

////  OR1200's Data TLB                                           ////

////                                                              ////

////  This file is part of the OpenRISC 1200 project              ////

////  http://www.opencores.org/project,or1k                       ////

////                                                              ////

////  Description                                                 ////

////  Instantiation of DTLB.                                      ////

////                                                              ////

////  To Do:                                                      ////

////   - make it smaller and faster                               ////

////                                                              ////

////  Author(s):                                                  ////

////      - Damjan Lampret, lampret@opencores.org                 ////

////                                                              ////

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

////                                                              ////

//// 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                     ////

////                                                              ////

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

//

//

// $Log: or1200_dmmu_tlb.v,v $

// Revision 2.0  2010/06/30 11:00:00  ORSoC

// Minor update: 

// Bugs fixed, coding style changed. 

//

// synopsys translate_off

`include "timescale.v"

// synopsys translate_on

`include "or1200_defines.v"

//

// Data TLB

//

module or1200_dmmu_tlb(

        // Rst and clk

        clk, rst,

        // I/F for translation

        tlb_en, vaddr, hit, ppn, uwe, ure, swe, sre, ci,

`ifdef OR1200_BIST

        // RAM BIST

        mbist_si_i, mbist_so_o, mbist_ctrl_i,

`endif

        // SPR access

        spr_cs, spr_write, spr_addr, spr_dat_i, spr_dat_o

);

parameter dw = `OR1200_OPERAND_WIDTH;

parameter aw = `OR1200_OPERAND_WIDTH;

//

// I/O

//

//

// Clock and reset

//

input                           clk;

input                           rst;

//

// I/F for translation

//

input                           tlb_en;

input   [aw-1:0]         vaddr;

output                          hit;

output  [31:`OR1200_DMMU_PS]    ppn;

output                          uwe;

output                          ure;

output                          swe;

output                          sre;

output                          ci;

`ifdef OR1200_BIST

//

// RAM BIST

//

input mbist_si_i;

input [`OR1200_MBIST_CTRL_WIDTH - 1:0] mbist_ctrl_i;

output mbist_so_o;

`endif

//

// SPR access

//

input                           spr_cs;

input                           spr_write;

input   [31:0]                   spr_addr;

input   [31:0]                   spr_dat_i;

output  [31:0]                   spr_dat_o;

//

// Internal wires and regs

//

wire    [`OR1200_DTLB_TAG]      vpn;

wire                            v;

wire    [`OR1200_DTLB_INDXW-1:0] tlb_index;

wire                            tlb_mr_en;

wire                            tlb_mr_we;

wire    [`OR1200_DTLBMRW-1:0]    tlb_mr_ram_in;

wire    [`OR1200_DTLBMRW-1:0]    tlb_mr_ram_out;

wire                            tlb_tr_en;

wire                            tlb_tr_we;

wire    [`OR1200_DTLBTRW-1:0]    tlb_tr_ram_in;

wire    [`OR1200_DTLBTRW-1:0]    tlb_tr_ram_out;

`ifdef OR1200_BIST

//

// RAM BIST

//

wire                            mbist_mr_so;

wire                            mbist_tr_so;

wire                            mbist_mr_si = mbist_si_i;

wire                            mbist_tr_si = mbist_mr_so;

assign                          mbist_so_o = mbist_tr_so;

`endif

//

// Implemented bits inside match and translate registers

//

// dtlbwYmrX: vpn 31-19  v 0

// dtlbwYtrX: ppn 31-13  swe 9  sre 8  uwe 7  ure 6

//

// dtlb memory width:

// 19 bits for ppn

// 13 bits for vpn

// 1 bit for valid

// 4 bits for protection

// 1 bit for cache inhibit

//

// Enable for Match registers

//

assign tlb_mr_en = tlb_en | (spr_cs & !spr_addr[`OR1200_DTLB_TM_ADDR]);

//

// Write enable for Match registers

//

assign tlb_mr_we = spr_cs & spr_write & !spr_addr[`OR1200_DTLB_TM_ADDR];

//

// Enable for Translate registers

//

assign tlb_tr_en = tlb_en | (spr_cs & spr_addr[`OR1200_DTLB_TM_ADDR]);

//

// Write enable for Translate registers

//

assign tlb_tr_we = spr_cs & spr_write & spr_addr[`OR1200_DTLB_TM_ADDR];

//

// Output to SPRS unit

//

assign spr_dat_o = (spr_cs & !spr_write & !spr_addr[`OR1200_DTLB_TM_ADDR]) ?

                        {vpn, tlb_index, {`OR1200_DTLB_TAGW-7{1'b0}}, 1'b0, 5'b00000, v} :

                (spr_cs & !spr_write & spr_addr[`OR1200_DTLB_TM_ADDR]) ?

                        {ppn, {`OR1200_DMMU_PS-10{1'b0}}, swe, sre, uwe, ure, {4{1'b0}}, ci, 1'b0} :

                        32'h00000000;

//

// Assign outputs from Match registers

//

assign {vpn, v} = tlb_mr_ram_out;

//

// Assign to Match registers inputs

//

assign tlb_mr_ram_in = {spr_dat_i[`OR1200_DTLB_TAG], spr_dat_i[`OR1200_DTLBMR_V_BITS]};

//

// Assign outputs from Translate registers

//

assign {ppn, swe, sre, uwe, ure, ci} = tlb_tr_ram_out;

//

// Assign to Translate registers inputs

//

assign tlb_tr_ram_in = {spr_dat_i[31:`OR1200_DMMU_PS],

                        spr_dat_i[`OR1200_DTLBTR_SWE_BITS],

                        spr_dat_i[`OR1200_DTLBTR_SRE_BITS],

                        spr_dat_i[`OR1200_DTLBTR_UWE_BITS],

                        spr_dat_i[`OR1200_DTLBTR_URE_BITS],

                        spr_dat_i[`OR1200_DTLBTR_CI_BITS]};

//

// Generate hit

//

assign hit = (vpn == vaddr[`OR1200_DTLB_TAG]) & v;

//

// TLB index is normally vaddr[18:13]. If it is SPR access then index is

// spr_addr[5:0].

//

assign tlb_index = spr_cs ? spr_addr[`OR1200_DTLB_INDXW-1:0] : vaddr[`OR1200_DTLB_INDX];

//

// Instantiation of DTLB Match Registers

//

//or1200_spram_64x14 dtlb_mr_ram(

   or1200_spram #

     (

      .aw(6),

      .dw(14)

      )

   dtlb_ram

     (

      .clk(clk),

`ifdef OR1200_BIST

      // RAM BIST

      .mbist_si_i(mbist_mr_si),

      .mbist_so_o(mbist_mr_so),

      .mbist_ctrl_i(mbist_ctrl_i),

`endif

      .ce(tlb_mr_en),

      .we(tlb_mr_we),

      .addr(tlb_index),

      .di(tlb_mr_ram_in),

      .doq(tlb_mr_ram_out)

      );

   //

   // Instantiation of DTLB Translate Registers

   //

   //or1200_spram_64x24 dtlb_tr_ram(

   or1200_spram #

     (

      .aw(6),

      .dw(24)

      )

   dtlb_tr_ram

     (

      .clk(clk),

`ifdef OR1200_BIST

      // RAM BIST

      .mbist_si_i(mbist_tr_si),

      .mbist_so_o(mbist_tr_so),

      .mbist_ctrl_i(mbist_ctrl_i),

`endif

      .ce(tlb_tr_en),

      .we(tlb_tr_we),

      .addr(tlb_index),

      .di(tlb_tr_ram_in),

      .doq(tlb_tr_ram_out)

      );

endmodule // or1200_dmmu_tlb