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//////////////////////////////////////////////////////////////////////
////                                                              ////
////  Versatile library, wishbone stuff                           ////
////                                                              ////
////  Description                                                 ////
////  Wishbone compliant modules                                  ////
////                                                              ////
////                                                              ////
////  To Do:                                                      ////
////   -                                                          ////
////                                                              ////
////  Author(s):                                                  ////
////      - Michael Unneback, unneback@opencores.org              ////
////        ORSoC AB                                              ////
////                                                              ////
//////////////////////////////////////////////////////////////////////
////                                                              ////
//// Copyright (C) 2010 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                     ////
////                                                              ////
//////////////////////////////////////////////////////////////////////
 
// async wb3 - wb3 bridge
`timescale 1ns/1ns
module vl_wb3wb3_bridge ( 
	// wishbone slave side
	wbs_dat_i, wbs_adr_i, wbs_sel_i, wbs_bte_i, wbs_cti_i, wbs_we_i, wbs_cyc_i, wbs_stb_i, wbs_dat_o, wbs_ack_o, wbs_clk, wbs_rst,
	// wishbone master side
	wbm_dat_o, wbm_adr_o, wbm_sel_o, wbm_bte_o, wbm_cti_o, wbm_we_o, wbm_cyc_o, wbm_stb_o, wbm_dat_i, wbm_ack_i, wbm_clk, wbm_rst);
 
input [31:0] wbs_dat_i;
input [31:2] wbs_adr_i;
input [3:0]  wbs_sel_i;
input [1:0]  wbs_bte_i;
input [2:0]  wbs_cti_i;
input wbs_we_i, wbs_cyc_i, wbs_stb_i;
output [31:0] wbs_dat_o;
output wbs_ack_o;
input wbs_clk, wbs_rst;
 
output [31:0] wbm_dat_o;
output reg [31:2] wbm_adr_o;
output [3:0]  wbm_sel_o;
output reg [1:0]  wbm_bte_o;
output reg [2:0]  wbm_cti_o;
output reg wbm_we_o;
output wbm_cyc_o;
output wbm_stb_o;
input [31:0]  wbm_dat_i;
input wbm_ack_i;
input wbm_clk, wbm_rst;
 
parameter addr_width = 4;
 
// bte
parameter linear       = 2'b00;
parameter wrap4        = 2'b01;
parameter wrap8        = 2'b10;
parameter wrap16       = 2'b11;
// cti
parameter classic      = 3'b000;
parameter incburst     = 3'b010;
parameter endofburst   = 3'b111;
 
parameter wbs_adr  = 1'b0;
parameter wbs_data = 1'b1;
 
parameter wbm_adr0 = 2'b00;
parameter wbm_adr1 = 2'b01;
parameter wbm_data = 2'b10;
 
reg [1:0] wbs_bte_reg;
reg wbs;
wire wbs_eoc_alert, wbm_eoc_alert;
reg wbs_eoc, wbm_eoc;
reg [1:0] wbm;
 
wire [1:16] wbs_count, wbm_count;
 
wire [35:0] a_d, a_q, b_d, b_q;
wire a_wr, a_rd, a_fifo_full, a_fifo_empty, b_wr, b_rd, b_fifo_full, b_fifo_empty;
reg a_rd_reg;
wire b_rd_adr, b_rd_data;
wire b_rd_data_reg;
wire [35:0] temp;
 
`define WE 5
`define BTE 4:3
`define CTI 2:0  
 
assign wbs_eoc_alert = (wbs_bte_reg==wrap4 & wbs_count[3]) | (wbs_bte_reg==wrap8 & wbs_count[7]) | (wbs_bte_reg==wrap16 & wbs_count[15]);
always @ (posedge wbs_clk or posedge wbs_rst)
if (wbs_rst)
	wbs_eoc <= 1'b0;
else
	if (wbs==wbs_adr & wbs_stb_i & !a_fifo_full)
		wbs_eoc <= wbs_bte_i==linear;
	else if (wbs_eoc_alert & (a_rd | a_wr))
		wbs_eoc <= 1'b1;
 
vl_cnt_shreg_ce_clear # ( .length(16))
    cnt0 (
        .cke(wbs_ack_o),
        .clear(wbs_eoc),
        .q(wbs_count),
        .rst(wbs_rst),
        .clk(wbs_clk));
 
always @ (posedge wbs_clk or posedge wbs_rst)
if (wbs_rst)
	wbs <= wbs_adr;
else
	if ((wbs==wbs_adr) & wbs_cyc_i & wbs_stb_i & !a_fifo_full)
		wbs <= wbs_data;
	else if (wbs_eoc & wbs_ack_o)
		wbs <= wbs_adr;
 
// wbs FIFO
assign a_d = (wbs==wbs_adr) ? {wbs_adr_i[31:2],wbs_we_i,wbs_bte_i,wbs_cti_i} : {wbs_dat_i,wbs_sel_i};
assign a_wr = (wbs==wbs_adr)  ? wbs_cyc_i & wbs_stb_i & !a_fifo_full :
              (wbs==wbs_data) ? wbs_we_i  & wbs_stb_i & !a_fifo_full :
              1'b0;
assign a_rd = !a_fifo_empty;
always @ (posedge wbs_clk or posedge wbs_rst)
if (wbs_rst)
	a_rd_reg <= 1'b0;
else
	a_rd_reg <= a_rd;
assign wbs_ack_o = a_rd_reg | (a_wr & wbs==wbs_data);
 
assign wbs_dat_o = a_q[35:4];
 
always @ (posedge wbs_clk or posedge wbs_rst)
if (wbs_rst)
	wbs_bte_reg <= 2'b00;
else
	wbs_bte_reg <= wbs_bte_i;
 
// wbm FIFO
assign wbm_eoc_alert = (wbm_bte_o==wrap4 & wbm_count[3]) | (wbm_bte_o==wrap8 & wbm_count[7]) | (wbm_bte_o==wrap16 & wbm_count[15]);
always @ (posedge wbm_clk or posedge wbm_rst)
if (wbm_rst)
	wbm_eoc <= 1'b0;
else
	if (wbm==wbm_adr0 & !b_fifo_empty)
		wbm_eoc <= b_q[`BTE] == linear;
	else if (wbm_eoc_alert & wbm_ack_i)
		wbm_eoc <= 1'b1;
 
always @ (posedge wbm_clk or posedge wbm_rst)
if (wbm_rst)
	wbm <= wbm_adr0;
else
    if ((wbm==wbm_adr0 & !b_fifo_empty) |
        (wbm==wbm_adr1 & !b_fifo_empty & wbm_we_o) |
        (wbm==wbm_adr1 & !wbm_we_o) |
        (wbm==wbm_data & wbm_ack_i & wbm_eoc))
        wbm <= {wbm[0],!(wbm[1] ^ wbm[0])};  // count sequence 00,01,10
 
assign b_d = {wbm_dat_i,4'b1111};
assign b_wr = !wbm_we_o & wbm_ack_i;
assign b_rd_adr  = (wbm==wbm_adr0 & !b_fifo_empty);
assign b_rd_data = (wbm==wbm_adr1 & !b_fifo_empty & wbm_we_o) ? 1'b1 : // b_q[`WE]
                   (wbm==wbm_data & !b_fifo_empty & wbm_we_o & wbm_ack_i & !wbm_eoc) ? 1'b1 :
                   1'b0;
assign b_rd = b_rd_adr | b_rd_data;
 
vl_dff dff1 ( .d(b_rd_data), .q(b_rd_data_reg), .clk(wbm_clk), .rst(wbm_rst));
vl_dff_ce # ( .width(36)) dff2 ( .d(b_q), .ce(b_rd_data_reg), .q(temp), .clk(wbm_clk), .rst(wbm_rst));
 
assign {wbm_dat_o,wbm_sel_o} = (b_rd_data_reg) ? b_q : temp;
 
vl_cnt_shreg_ce_clear # ( .length(16))
    cnt1 (
        .cke(wbm_ack_i),
        .clear(wbm_eoc),
        .q(wbm_count),
        .rst(wbm_rst),
        .clk(wbm_clk));
 
assign wbm_cyc_o = wbm==wbm_data;
assign wbm_stb_o = (wbm==wbm_data & wbm_we_o) ? !b_fifo_empty : 
                   (wbm==wbm_data) ? 1'b1 :
                   1'b0;
 
always @ (posedge wbm_clk or posedge wbm_rst)
if (wbm_rst)
	{wbm_adr_o,wbm_we_o,wbm_bte_o,wbm_cti_o} <= {30'h0,1'b0,linear,classic};
else begin
	if (wbm==wbm_adr0 & !b_fifo_empty)
		{wbm_adr_o,wbm_we_o,wbm_bte_o,wbm_cti_o} <= b_q;
	else if (wbm_eoc_alert & wbm_ack_i)
		wbm_cti_o <= endofburst;
end	
 
//async_fifo_dw_simplex_top
vl_fifo_2r2w_async_simplex
# ( .data_width(36), .addr_width(addr_width))
fifo (
    // a side
    .a_d(a_d), 
    .a_wr(a_wr), 
    .a_fifo_full(a_fifo_full),
    .a_q(a_q),
    .a_rd(a_rd),
    .a_fifo_empty(a_fifo_empty), 
    .a_clk(wbs_clk), 
    .a_rst(wbs_rst),
    // b side
    .b_d(b_d), 
    .b_wr(b_wr), 
    .b_fifo_full(b_fifo_full),
    .b_q(b_q), 
    .b_rd(b_rd), 
    .b_fifo_empty(b_fifo_empty), 
    .b_clk(wbm_clk), 
    .b_rst(wbm_rst)	
    );
 
endmodule
 
// WB ROM
module vl_wb_boot_rom (
    wb_adr_i, wb_stb_i, wb_cyc_i, 
    wb_dat_o, wb_ack_o, hit_o, wb_clk, wb_rst);
 
    parameter adr_hi = 31;
    parameter adr_lo = 28;
    parameter adr_sel = 4'hf;
    parameter addr_width = 5;
 
//E2_ifndef BOOT_ROM
//E2_define BOOT_ROM "boot_rom.v"
//E2_endif
 
    input [adr_hi:2]    wb_adr_i;
    input 		wb_stb_i;
    input 		wb_cyc_i;
    output [31:0] 	wb_dat_o;
    output  		wb_ack_o;
    output              hit_o;
    input 		wb_clk;
    input 		wb_rst;
 
    wire hit;
    reg [31:0] wb_dat;
    reg wb_ack;
 
assign hit = wb_adr_i[adr_hi:adr_lo] == adr_sel;
 
always @ (posedge wb_clk or posedge wb_rst)
    if (wb_rst)
        wb_dat <= 32'h15000000;
    else
	 case (wb_adr_i[addr_width-1:2])
//E2_include `BOOT_ROM
	   /*	 
	    // Zero r0 and jump to 0x00000100
	    0 : wb_dat <= 32'h18000000;
	    1 : wb_dat <= 32'hA8200000;
	    2 : wb_dat <= 32'hA8C00100;
	    3 : wb_dat <= 32'h44003000;
	    4 : wb_dat <= 32'h15000000;
	    */
	   default:
	     wb_dat <= 32'h00000000;
 
	 endcase // case (wb_adr_i)
 
 
always @ (posedge wb_clk or posedge wb_rst)
    if (wb_rst)
        wb_ack <= 1'b0;
    else
        wb_ack <= wb_stb_i & wb_cyc_i & hit & !wb_ack;
 
assign hit_o = hit;
assign wb_dat_o = wb_dat & {32{wb_ack}};
assign wb_ack_o = wb_ack;
 
endmodule