| ////////////////////////////////////////////////////////////////////////////// |
| // SPDX-FileCopyrightText: 2021 , Dinesh Annayya |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| // SPDX-License-Identifier: Apache-2.0 |
| // SPDX-FileContributor: Created by Dinesh Annayya <dinesha@opencores.org> |
| // |
| ////////////////////////////////////////////////////////////////////// |
| //// //// |
| //// sync Wishbone Interface iBurst Enable and lack //// |
| //// //// |
| //// This file is part of the YIFive cores project //// |
| //// http://www.opencores.org/cores/yifive/ //// |
| //// //// |
| //// Description //// |
| //// This block does async Wishbone from one clock to other //// |
| //// clock domain |
| //// //// |
| //// To Do: //// |
| //// nothing //// |
| //// //// |
| //// Author(s): //// |
| //// - Dinesh Annayya, dinesha@opencores.org //// |
| //// //// |
| //// Revision : //// |
| //// 0.1 - 25th Feb 2021, Dinesh A //// |
| //// initial version //// |
| //// 0.2 - 28th Feb 2021, Dinesh A //// |
| //// reduced the response FIFO path depth to 2 as //// |
| //// return path used by only read logic and read is //// |
| //// blocking request and expect only one location will //// |
| //// be used //// |
| //// 0.3 - 20 Jan 2022, Dinesh A //// |
| //// added wishbone burst mode. Additional signal added //// |
| //// A. *bl - 10 Bit word Burst count, 1 - 1 DW(32 bit)//// |
| //// B. *lack - Last Burst ack //// |
| ////////////////////////////////////////////////////////////////////// |
| //// //// |
| //// 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 //// |
| //// //// |
| ////////////////////////////////////////////////////////////////////// |
| |
| module sync_wbb |
| #(parameter AW = 32, |
| parameter BW = 4, |
| parameter BL = 10, |
| parameter DW = 32) |
| ( |
| |
| // Master Port |
| input logic rst_n , // Regular Reset signal |
| input logic clk_i , // System clock |
| input logic wbm_cyc_i , // strobe/request |
| input logic wbm_stb_i , // strobe/request |
| input logic [AW-1:0] wbm_adr_i , // address |
| input logic wbm_we_i , // write |
| input logic [DW-1:0] wbm_dat_i , // data output |
| input logic [BW-1:0] wbm_sel_i , // byte enable |
| input logic [3:0] wbm_tid_i , |
| input logic [BL-1:0] wbm_bl_i , // Burst Count |
| input logic wbm_bry_i , // Burst Ready |
| output logic [DW-1:0] wbm_dat_o , // data input |
| output logic wbm_ack_o , // acknowlegement |
| output logic wbm_lack_o , // Last Burst access |
| output logic wbm_err_o , // error |
| |
| // Slave Port |
| output logic wbs_cyc_o , // strobe/request |
| output logic wbs_stb_o , // strobe/request |
| output logic [AW-1:0] wbs_adr_o , // address |
| output logic wbs_we_o , // write |
| output logic [DW-1:0] wbs_dat_o , // data output |
| output logic [BW-1:0] wbs_sel_o , // byte enable |
| output logic [3:0] wbs_tid_o , |
| output logic [BL-1:0] wbs_bl_o , // Burst Count |
| output logic wbs_bry_o , // Busrt WData Avialble Or Ready To accept Rdata |
| input logic [DW-1:0] wbs_dat_i , // data input |
| input logic wbs_ack_i , // acknowlegement |
| input logic wbs_lack_i , // Last Ack |
| input logic wbs_err_i // error |
| |
| ); |
| |
| |
| |
| parameter CFW = AW+DW+BW+BL+4+1 ; // COMMAND FIFO WIDTH |
| parameter RFW = DW+1+1 ; // RESPONSE FIFO WIDTH |
| |
| parameter IDLE = 2'b00; |
| parameter WRITE_DATA = 2'b01; |
| parameter READ_DATA = 2'b10; |
| |
| |
| //------------------------------------------------- |
| // Master Interface |
| // ------------------------------------------------- |
| logic m_cmd_wr_en ; |
| logic [CFW-1:0] m_cmd_wr_data ; |
| logic m_cmd_wr_full ; |
| logic m_cmd_wr_afull ; |
| |
| logic m_resp_rd_empty ; |
| logic m_resp_rd_aempty ; |
| logic m_resp_rd_en ; |
| logic [RFW-1:0] m_resp_rd_data ; |
| logic [BL-1:0] m_bl_cnt ; |
| logic [1:0] m_state ; |
| |
| // Master Write Interface |
| |
| |
| |
| assign m_cmd_wr_data = {wbm_adr_i,wbm_we_i,wbm_dat_i,wbm_sel_i,wbm_tid_i,wbm_bl_i}; |
| |
| assign wbm_dat_o = m_resp_rd_data[DW-1:0]; |
| assign wbm_err_o = 'b0; |
| |
| always@(negedge rst_n or posedge clk_i) |
| begin |
| if(rst_n == 0) begin |
| m_cmd_wr_en <= 'b0; |
| m_resp_rd_en <= 'b0; |
| m_state <= 'h0; |
| m_bl_cnt <= 'h0; |
| wbm_ack_o <= 'b0; |
| wbm_lack_o <= 'b0; |
| end else begin |
| case(m_state) |
| IDLE: begin |
| // Read DATA |
| if(wbm_stb_i && !wbm_we_i && wbm_bry_i && !m_cmd_wr_full && !wbm_lack_o) begin |
| m_bl_cnt <= wbm_bl_i; |
| m_cmd_wr_en <= 'b1; |
| m_state <= READ_DATA; |
| end else if(wbm_stb_i && wbm_we_i && wbm_bry_i && !m_cmd_wr_full && !wbm_lack_o) begin |
| wbm_ack_o <= 'b1; |
| m_cmd_wr_en <= 'b1; |
| m_bl_cnt <= wbm_bl_i-1; |
| if(wbm_bl_i == 'h1) begin |
| wbm_lack_o <= 'b1; |
| m_state <= IDLE; |
| end else begin |
| m_bl_cnt <= wbm_bl_i-1; |
| m_state <= WRITE_DATA; |
| end |
| end else begin |
| m_resp_rd_en <= 'b0; |
| m_cmd_wr_en <= 'b0; |
| wbm_ack_o <= 'b0; |
| wbm_lack_o <= 'b0; |
| end |
| end |
| |
| // Write next Transaction |
| WRITE_DATA: begin |
| if(m_cmd_wr_full != 1 && wbm_bry_i) begin |
| wbm_ack_o <= 'b1; |
| m_cmd_wr_en <= 'b1; |
| if(m_bl_cnt == 1) begin |
| wbm_lack_o <= 'b1; |
| m_state <= IDLE; |
| end else begin |
| m_bl_cnt <= m_bl_cnt-1; |
| end |
| end else begin |
| m_cmd_wr_en <= 'b0; |
| wbm_ack_o <= 'b0; |
| wbm_lack_o <= 'b0; |
| end |
| end |
| |
| // Read Transaction |
| READ_DATA: begin |
| // Check Back to Back Ack and last Location case |
| if(((wbm_ack_o == 0 && m_resp_rd_empty != 1) || |
| (wbm_ack_o == 1 && m_resp_rd_aempty != 1)) && wbm_bry_i) begin |
| m_resp_rd_en <= 'b1; |
| wbm_ack_o <= 'b1; |
| if(m_bl_cnt == 1) begin |
| wbm_lack_o <= 'b1; |
| m_state <= IDLE; |
| end else begin |
| m_bl_cnt <= m_bl_cnt-1; |
| end |
| end else begin |
| m_resp_rd_en <= 'b0; |
| m_cmd_wr_en <= 'b0; |
| wbm_ack_o <= 'b0; |
| wbm_lack_o <= 'b0; |
| end |
| end |
| endcase |
| end |
| end |
| |
| |
| //------------------------------ |
| // Slave Interface |
| //------------------------------- |
| |
| logic [CFW-1:0] s_cmd_rd_data ; |
| logic [CFW-1:0] s_cmd_rd_data_l ; |
| logic s_cmd_rd_empty ; |
| logic s_cmd_rd_aempty ; |
| logic s_cmd_rd_en ; |
| logic s_resp_wr_en ; |
| logic [RFW-1:0] s_resp_wr_data ; |
| logic s_resp_wr_full ; |
| logic s_resp_wr_afull ; |
| logic wbs_ack_f ; |
| logic wbs_stb_l ; |
| logic wbs_burst ; |
| |
| wire wbs_stb_pedge = (wbs_stb_l == 1'b0) && wbs_stb_o; |
| |
| |
| always@(negedge rst_n or posedge clk_i) |
| begin |
| if(rst_n == 0) begin |
| wbs_ack_f <= 1'b0; |
| wbs_stb_l <= 1'b0; |
| wbs_burst <= 'h0; |
| s_cmd_rd_data_l <= 'h0; |
| end else begin |
| wbs_ack_f <= wbs_lack_i; |
| wbs_stb_l <= wbs_stb_o; |
| if(s_cmd_rd_en) |
| s_cmd_rd_data_l <= s_cmd_rd_data; |
| if(wbs_stb_pedge && wbs_bl_o > 'h1) |
| wbs_burst <= 1'b1; |
| else if(wbs_lack_i) |
| wbs_burst <= 1'b0; |
| end |
| end |
| |
| |
| // Read Interface |
| |
| |
| assign {wbs_adr_o,wbs_we_o,wbs_dat_o,wbs_sel_o,wbs_tid_o,wbs_bl_o} = (s_cmd_rd_empty) ? s_cmd_rd_data_l: s_cmd_rd_data; |
| // All the downstream logic expect Stobe is getting de-asserted |
| // atleast for 1 cycle after ack is generated |
| assign wbs_stb_o = (wbs_burst) ? 1'b1 : ((wbs_ack_f) ? 1'b0 : (s_cmd_rd_empty) ? 1'b0: 1'b1); |
| assign wbs_cyc_o = (wbs_burst) ? 1'b1 : ((wbs_ack_f) ? 1'b0 : (s_cmd_rd_empty) ? 1'b0: 1'b1); |
| |
| // Generate bust ready only we have space inside response fifo |
| // In Write Phase, |
| // Generate burst ready, only when we have wdata & space in response fifo |
| // In Read Phase |
| // Generate burst ready, only when space in response fifo |
| // |
| assign wbs_bry_o = (wbs_we_o) ? ((s_cmd_rd_empty || (s_cmd_rd_en && s_cmd_rd_aempty)) ? 1'b0: 1'b1) : |
| (s_resp_wr_full || (s_resp_wr_en && s_resp_wr_afull)) ? 1'b0: 1'b1; |
| |
| // During Write phase, cmd fifo will have wdata, so dequeue for every ack |
| // During Read Phase, cmd fifo will be written only one time, hold the bus |
| // untill last ack received |
| assign s_cmd_rd_en = (wbs_stb_o && wbs_we_o) ? wbs_ack_i: wbs_lack_i; |
| |
| // Write Interface |
| // response send only for read logic |
| assign s_resp_wr_en = wbs_stb_o & (!wbs_we_o) & wbs_ack_i ; |
| assign s_resp_wr_data = {wbs_err_i,wbs_lack_i,wbs_dat_i}; |
| |
| sync_fifo2 #(.W(CFW), .DP(4),.WR_FAST(1), .RD_FAST(1)) u_cmd_if ( |
| // Sync w.r.t WR clock |
| .clk (clk_i ), |
| .reset_n (rst_n ), |
| .wr_en (m_cmd_wr_en ), |
| .wr_data (m_cmd_wr_data ), |
| .full (m_cmd_wr_full ), |
| .afull (m_cmd_wr_afull ), |
| |
| // Sync w.r.t RD Clock |
| .rd_en (s_cmd_rd_en ), |
| .empty (s_cmd_rd_empty ), // sync'ed to rd_clk |
| .aempty (s_cmd_rd_aempty ), // sync'ed to rd_clk |
| .rd_data (s_cmd_rd_data ) |
| ); |
| |
| |
| // Response used only for read path, |
| // As cache access will be busrt of 512 location, To |
| // support continous ack, depth is increase to 8 location |
| sync_fifo2 #(.W(RFW), .DP(4), .WR_FAST(1), .RD_FAST(1)) u_resp_if ( |
| // Sync w.r.t WR clock |
| .clk (clk_i ), |
| .reset_n (rst_n ), |
| .wr_en (s_resp_wr_en ), |
| .wr_data (s_resp_wr_data ), |
| .full (s_resp_wr_full ), |
| .afull (s_resp_wr_afull ), |
| |
| // Sync w.r.t RD Clock |
| .rd_en (m_resp_rd_en ), |
| .empty (m_resp_rd_empty ), // sync'ed to rd_clk |
| .aempty (m_resp_rd_aempty ), // sync'ed to rd_clk |
| .rd_data (m_resp_rd_data ) |
| ); |
| |
| |
| |
| endmodule |
