| ////////////////////////////////////////////////////////////////////////////// |
| // 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: Dinesh Annayya <dinesha@opencores.org> |
| // ////////////////////////////////////////////////////////////////////////// |
| ////////////////////////////////////////////////////////////////////// |
| //// //// |
| //// yifive Wishbone interface for Instruction memory //// |
| //// //// |
| //// This file is part of the yifive cores project //// |
| //// https://github.com/dineshannayya/yifive_r0.git //// |
| //// http://www.opencores.org/cores/yifive/ //// |
| //// //// |
| //// Description: //// |
| //// integrated wishbone i/f to instruction memory //// |
| //// //// |
| //// To Do: //// |
| //// nothing //// |
| //// //// |
| //// Author(s): //// |
| //// - Dinesh Annayya, dinesha@opencores.org //// |
| //// //// |
| //// Revision : //// |
| //// v0: June 7, 2021, Dinesh A //// |
| //// wishbone integration //// |
| //// v1: June 9, 2021, Dinesh A //// |
| //// On power up, wishbone output are unkown as it //// |
| //// driven from fifo output. To avoid unknown //// |
| //// propgation, we are driving 'h0 when fifo empty //// |
| //// v2: June 18, 2021, Dinesh A //// |
| //// core and wishbone is made async and async fifo //// |
| //// added to take care of domain cross-over //// |
| //// //// |
| ////////////////////////////////////////////////////////////////////// |
| //// //// |
| //// 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 //// |
| //// //// |
| ////////////////////////////////////////////////////////////////////// |
| // Orginal owner Details //// |
| ////////////////////////////////////////////////////////////////////// |
| /// Copyright by Syntacore LLC © 2016-2021. See LICENSE for details/// |
| /// @file <scr1_imem_wb.sv> /// |
| /// @brief Instruction memory AHB bridge /// |
| ////////////////////////////////////////////////////////////////////// |
| |
| `include "scr1_wb.svh" |
| `include "scr1_memif.svh" |
| |
| module scr1_imem_wb ( |
| // Control Signals |
| input logic core_rst_n, // core reset |
| input logic core_clk, // Core clock |
| |
| // Core Interface |
| output logic imem_req_ack, |
| input logic imem_req, |
| input logic [SCR1_WB_WIDTH-1:0] imem_addr, |
| output logic [SCR1_WB_WIDTH-1:0] imem_rdata, |
| output logic [1:0] imem_resp, |
| |
| // WB Interface |
| input logic wb_rst_n, // wishbone reset |
| input logic wb_clk, // wishbone clock |
| output logic wbd_stb_o, // strobe/request |
| output logic [SCR1_WB_WIDTH-1:0] wbd_adr_o, // address |
| output logic wbd_we_o, // write |
| output logic [SCR1_WB_WIDTH-1:0] wbd_dat_o, // data output |
| output logic [3:0] wbd_sel_o, // byte enable |
| input logic [SCR1_WB_WIDTH-1:0] wbd_dat_i, // data input |
| input logic wbd_ack_i, // acknowlegement |
| input logic wbd_err_i // error |
| |
| ); |
| |
| //------------------------------------------------------------------------------- |
| // Local parameters declaration |
| //------------------------------------------------------------------------------- |
| |
| //------------------------------------------------------------------------------- |
| // Local types declaration |
| //------------------------------------------------------------------------------- |
| |
| typedef struct packed { |
| logic [SCR1_WB_WIDTH-1:0] haddr; |
| } type_scr1_req_fifo_s; |
| |
| typedef struct packed { |
| logic hresp; |
| logic [SCR1_WB_WIDTH-1:0] hrdata; |
| } type_scr1_resp_fifo_s; |
| |
| //------------------------------------------------------------------------------- |
| // Local signal declaration |
| //------------------------------------------------------------------------------- |
| |
| //------------------------------------------------------------------------------- |
| // Request FIFO |
| // ------------------------------------------------------------------------------ |
| logic req_fifo_rd; |
| logic req_fifo_wr; |
| logic req_fifo_empty; |
| logic req_fifo_full; |
| |
| |
| //----------------------------------------------------- |
| // Response FIFO (READ PATH |
| // ---------------------------------------------------- |
| logic resp_fifo_empty; |
| logic resp_fifo_rd; |
| |
| |
| |
| //------------------------------------------------------------------------------- |
| // REQ_FIFO |
| //------------------------------------------------------------------------------- |
| type_scr1_req_fifo_s req_fifo_din; |
| type_scr1_req_fifo_s req_fifo_dout; |
| |
| assign req_fifo_wr = ~req_fifo_full & imem_req; |
| assign imem_req_ack = ~req_fifo_full; |
| |
| assign req_fifo_din.haddr = imem_addr; |
| |
| async_fifo #( |
| .W(SCR1_WB_WIDTH), // Data Width |
| .DP(4), // FIFO DEPTH |
| .WR_FAST(1), // We need FF'ed Full |
| .RD_FAST(1) // We need FF'ed Empty |
| ) u_req_fifo( |
| // Writc Clock |
| .wr_clk (core_clk ), |
| .wr_reset_n (core_rst_n ), |
| .wr_en (req_fifo_wr ), |
| .wr_data (req_fifo_din ), |
| .full (req_fifo_full ), |
| .afull ( ), |
| |
| // RD Clock |
| .rd_clk (wb_clk ), |
| .rd_reset_n (wb_rst_n ), |
| .rd_en (req_fifo_rd ), |
| .empty (req_fifo_empty ), |
| .aempty ( ), |
| .rd_data (req_fifo_dout ) |
| ); |
| |
| |
| always_comb begin |
| req_fifo_rd = 1'b0; |
| if (wbd_ack_i) begin |
| req_fifo_rd = ~req_fifo_empty; |
| end |
| end |
| |
| assign wbd_stb_o = ~req_fifo_empty; |
| // On Power, to avoid unknow propgating the value |
| assign wbd_adr_o = (req_fifo_empty) ? 'h0 : req_fifo_dout.haddr; |
| assign wbd_we_o = 0; // Only Read supported |
| assign wbd_dat_o = 32'h0; // No Write |
| assign wbd_sel_o = 4'b1111; // Only Read allowed in imem i/f |
| //------------------------------------------------------------------------------- |
| // Response path - Used by Read path logic |
| //------------------------------------------------------------------------------- |
| type_scr1_resp_fifo_s resp_fifo_din; |
| type_scr1_resp_fifo_s resp_fifo_dout; |
| |
| assign resp_fifo_din.hresp = (wbd_err_i) ? 1'b0 : 1'b1; |
| assign resp_fifo_din.hrdata = wbd_dat_i; |
| |
| async_fifo #( |
| .W(SCR1_WB_WIDTH+1), // Data Width |
| .DP(4), // FIFO DEPTH |
| .WR_FAST(1), // We need FF'ed Full |
| .RD_FAST(1) // We need FF'ed Empty |
| ) u_res_fifo( |
| // Writc Clock |
| .wr_clk (wb_clk ), |
| .wr_reset_n (wb_rst_n ), |
| .wr_en (wbd_ack_i ), |
| .wr_data (resp_fifo_din ), |
| .full ( ), // Assmed FIFO will never be full as it's Response a Single Request |
| .afull ( ), |
| |
| // RD Clock |
| .rd_clk (core_clk ), |
| .rd_reset_n (core_rst_n ), |
| .rd_en (resp_fifo_rd ), |
| .empty (resp_fifo_empty ), |
| .aempty ( ), |
| .rd_data (resp_fifo_dout ) |
| ); |
| |
| |
| assign resp_fifo_rd = !resp_fifo_empty; |
| assign imem_rdata = resp_fifo_dout.hrdata; |
| |
| assign imem_resp = (resp_fifo_rd) |
| ? (resp_fifo_dout.hresp == 1'b1) |
| ? SCR1_MEM_RESP_RDY_OK |
| : SCR1_MEM_RESP_RDY_ER |
| : SCR1_MEM_RESP_NOTRDY ; |
| |
| |
| `ifdef SCR1_TRGT_SIMULATION |
| //------------------------------------------------------------------------------- |
| // Assertion |
| //------------------------------------------------------------------------------- |
| |
| // Check Core interface |
| SCR1_SVA_IMEM_WB_BRIDGE_REQ_XCHECK : assert property ( |
| @(negedge core_clk) disable iff (~core_rst_n) |
| !$isunknown(imem_req) |
| ) else $error("IMEM WB bridge Error: imem_req has unknown values"); |
| |
| SCR1_IMEM_WB_BRIDGE_ADDR_XCHECK : assert property ( |
| @(negedge core_clk) disable iff (~core_rst_n) |
| imem_req |-> !$isunknown(imem_addr) |
| ) else $error("IMEM WB bridge Error: imem_addr has unknown values"); |
| |
| SCR1_IMEM_WB_BRIDGE_ADDR_ALLIGN : assert property ( |
| @(negedge core_clk) disable iff (~core_rst_n) |
| imem_req |-> (imem_addr[1:0] == '0) |
| ) else $error("IMEM WB bridge Error: imem_addr has unalign values"); |
| |
| // Check WB interface |
| SCR1_IMEM_WB_BRIDGE_HREADY_XCHECK : assert property ( |
| @(negedge core_clk) disable iff (~core_rst_n) |
| !$isunknown(imem_req_ack) |
| ) else $error("IMEM WB bridge Error: imem_req_ack has unknown values"); |
| |
| SCR1_IMEM_WB_BRIDGE_HRESP_XCHECK : assert property ( |
| @(negedge core_clk) disable iff (~core_rst_n) |
| !$isunknown(imem_resp) |
| ) else $error("IMEM WB bridge Error: imem_resp has unknown values"); |
| |
| `endif // SCR1_TRGT_SIMULATION |
| |
| endmodule : scr1_imem_wb |
