adding Axi4lite Master to WB Slave bridge

8bc23caf · Grzegorz Daniluk · a472d47f · 8bc23caf · 8bc23caf
Commit 8bc23caf authored Apr 17, 2019 by Grzegorz Daniluk
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Manifest.py modules/wishbone/wb_axi4lite_bridge/Manifest.py +2 -1

xaxi4lite_wb_bridge.vhd modules/wishbone/wb_axi4lite_bridge/xaxi4lite_wb_bridge.vhd +178 -0

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--- a/modules/wishbone/wb_axi4lite_bridge/Manifest.py
+++ b/modules/wishbone/wb_axi4lite_bridge/Manifest.py
 files = [
    "axi4_pkg.vhd",
    "wb_axi4lite_bridge.vhd",
-    "xwb_axi4lite_bridge.vhd"
+    "xwb_axi4lite_bridge.vhd",
+    "xaxi4lite_wb_bridge.vhd"
 ]
--- a/modules/wishbone/wb_axi4lite_bridge/xaxi4lite_wb_bridge.vhd
+++ b/modules/wishbone/wb_axi4lite_bridge/xaxi4lite_wb_bridge.vhd
+-------------------------------------------------------------------------------
+-- Title      : WB-to-AXI4Lite bridge
+-- Project    : General Cores
+-------------------------------------------------------------------------------
+-- File       : xaxi4lite_wb_bridge.vhd
+-- Author     : Grzegorz Daniluk
+-- Company    : CERN
+-- Platform   : FPGA-generics
+-- Standard   : VHDL '93
+-------------------------------------------------------------------------------
+-- Description:
+--
+-- This module is a WB Slave Classic to AXI4-Lite Master bridge.
+-------------------------------------------------------------------------------
+-- Copyright (c) 2019 CERN
+--------------------------------------------------------------------------------
+-- Copyright and related rights are licensed under the Solderpad Hardware
+-- 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://solderpad.org/licenses/SHL-2.0.
+-- Unless required by applicable law or agreed to in writing, software,
+-- hardware and materials distributed under this 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.
+--------------------------------------------------------------------------------
+
+library ieee;
+use ieee.std_logic_1164.all;
+
+use work.axi4_pkg.all;
+use work.wishbone_pkg.all;
+
+entity xaxi4lite_wb_bridge is
+  port (
+    clk_i         : in std_logic;
+    rst_n_i       : in std_logic;
+
+    wb_slave_i    : in  t_wishbone_slave_in;
+    wb_slave_o    : out t_wishbone_slave_out;
+
+    axi4_master_o : out t_axi4_lite_master_out_32;
+    axi4_master_i : in  t_axi4_lite_master_in_32);
+end xaxi4lite_wb_bridge;
+
+architecture behav of xaxi4lite_wb_bridge is
+
+  type t_state is (IDLE, READ, WRITE, WB_END);
+  signal state : t_state;
+
+begin
+
+  wb_slave_o.stall <= '0';
+
+  process(clk_i)
+  begin
+    if rising_edge(clk_i) then
+      if rst_n_i = '0' then
+        wb_slave_o.ack <= '0';
+        wb_slave_o.err <= '0';
+        axi4_master_o  <= c_axi4_lite_default_master_out_32;
+
+        state <= IDLE;
+      else
+        case state is
+
+          -------------------------------------------
+          when IDLE =>
+            wb_slave_o.ack   <= '0';
+            wb_slave_o.err <= '0';
+
+            axi4_master_o.ARVALID <= '0';
+            axi4_master_o.ARADDR  <= (others=>'X');
+            axi4_master_o.RREADY  <= '0';
+
+            axi4_master_o.AWVALID <= '0';
+            axi4_master_o.AWADDR  <= (others=>'X');
+            axi4_master_o.WVALID  <= '0';
+            axi4_master_o.WDATA   <= (others=>'X');
+            axi4_master_o.WSTRB   <= "0000";
+            axi4_master_o.BREADY  <= '0';
+
+            if wb_slave_i.stb = '1' and wb_slave_i.we = '0' then
+              -- AXI: set address for read cycle
+              axi4_master_o.ARVALID <= '1';
+              axi4_master_o.ARADDR  <= wb_slave_i.adr;
+              -- AXI: ready to accept data from slave
+              axi4_master_o.RREADY  <= '1';
+              state <= READ;
+            elsif (wb_slave_i.stb = '1' and wb_slave_i.we = '1') then
+              -- AXI: set address for write cycle
+              axi4_master_o.AWVALID <= '1';
+              axi4_master_o.AWADDR  <= wb_slave_i.adr;
+              -- AXI: set data for write cycle
+              axi4_master_o.WVALID  <= '1';
+              axi4_master_o.WDATA   <= wb_slave_i.dat;
+              axi4_master_o.WSTRB   <= wb_slave_i.sel;
+              state <= WRITE;
+            end if;
+
+          -------------------------------------------
+          --            READ CYCLE                 --
+          -------------------------------------------
+          when READ =>
+            wb_slave_o.ack   <= '0';
+            wb_slave_o.err <= '0';
+
+            axi4_master_o.RREADY  <= '1';
+
+            if (axi4_master_i.ARREADY = '1') then
+              -- AXI: address received by slave
+              axi4_master_o.ARVALID <= '0';
+            end if;
+            if (axi4_master_i.RVALID = '1' and axi4_master_i.RRESP = c_AXI4_RESP_OKAY) then
+              -- received valid data, pass it to wishbone
+              wb_slave_o.dat <= axi4_master_i.RDATA;
+              wb_slave_o.ack <= '1';
+              wb_slave_o.err <= '0';
+            elsif (axi4_master_i.RVALID = '1') then
+              wb_slave_o.ack <= '0';
+              wb_slave_o.err <= '1';
+            else
+              wb_slave_o.ack <= '0';
+              wb_slave_o.err <= '0';
+            end if;
+
+            if (axi4_master_i.RVALID = '1') then
+              axi4_master_o.RREADY <= '0';
+              state <= WB_END;
+            end if;
+
+          -------------------------------------------
+          --            WRITE CYCLE                --
+          -------------------------------------------
+          when WRITE =>
+            wb_slave_o.ack <= '0';
+            wb_slave_o.err <= '0';
+            axi4_master_o.BREADY <= '1';
+
+            if (axi4_master_i.AWREADY = '1') then
+              axi4_master_o.AWVALID <= '0';
+            end if;
+            if (axi4_master_i.WREADY = '1') then
+              axi4_master_o.WVALID <= '0';
+            end if;
+
+            if (axi4_master_i.BVALID = '1' and axi4_master_i.BRESP = c_AXI4_RESP_OKAY) then
+              wb_slave_o.ack <= '1';
+              wb_slave_o.err <= '0';
+            elsif (axi4_master_i.BVALID = '1') then
+              wb_slave_o.ack <= '0';
+              wb_slave_o.err <= '1';
+            else
+              wb_slave_o.ack <= '0';
+              wb_slave_o.err <= '0';
+            end if;
+
+            if (axi4_master_i.BVALID = '1') then
+              axi4_master_o.BREADY <= '0';
+              state <= WB_END;
+            end if;
+
+          -------------------------------------------
+          when WB_END =>
+            wb_slave_o.ack <= '0';
+            wb_slave_o.err <= '0';
+
+            -- WB: wait for the cycle to end
+            if (wb_slave_i.stb = '0') then
+              state <= IDLE;
+            end if;
+
+        end case;
+      end if;
+    end if;
+  end process;
+
+end behav;