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axi_cdc.sv
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axi_cdc.sv
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// Copyright (c) 20192-2020 ETH Zurich, University of Bologna
//
// Copyright and related rights are licensed under the Solderpad Hardware
// License, Version 0.51 (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-0.51. 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.
//
// Authors:
// - Andreas Kurth <[email protected]>
// - Fabian Schuiki <[email protected]>
// - Florian Zaruba <[email protected]>
// - Wolfgang Roenninger <[email protected]>
`include "axi/assign.svh"
/// A clock domain crossing on an AXI interface.
///
/// For each of the five AXI channels, this module instantiates a CDC FIFO, whose push and pop
/// ports are in separate clock domains. IMPORTANT: For each AXI channel, you MUST properly
/// constrain three paths through the FIFO; see the header of `cdc_fifo_gray` for instructions.
module axi_cdc #(
parameter type aw_chan_t = logic, // AW Channel Type
parameter type w_chan_t = logic, // W Channel Type
parameter type b_chan_t = logic, // B Channel Type
parameter type ar_chan_t = logic, // AR Channel Type
parameter type r_chan_t = logic, // R Channel Type
parameter type axi_req_t = logic, // encapsulates request channels
parameter type axi_resp_t = logic, // encapsulates request channels
/// Depth of the FIFO crossing the clock domain, given as 2**LOG_DEPTH.
parameter int unsigned LogDepth = 1
) (
// slave side - clocked by `src_clk_i`
input logic src_clk_i,
input logic src_rst_ni,
input axi_req_t src_req_i,
output axi_resp_t src_resp_o,
// master side - clocked by `dst_clk_i`
input logic dst_clk_i,
input logic dst_rst_ni,
output axi_req_t dst_req_o,
input axi_resp_t dst_resp_i
);
cdc_fifo_gray #(
// We need to cast to bits here because of some arbitrary bug in Synopsys.
.WIDTH ( $bits(aw_chan_t) ),
.LOG_DEPTH ( LogDepth )
) i_cdc_fifo_gray_aw (
.src_rst_ni,
.src_clk_i,
.src_data_i ( src_req_i.aw ),
.src_valid_i ( src_req_i.aw_valid ),
.src_ready_o ( src_resp_o.aw_ready ),
.dst_rst_ni,
.dst_clk_i,
.dst_data_o ( dst_req_o.aw ),
.dst_valid_o ( dst_req_o.aw_valid ),
.dst_ready_i ( dst_resp_i.aw_ready )
);
cdc_fifo_gray #(
.WIDTH ( $bits(w_chan_t) ),
.LOG_DEPTH ( LogDepth )
) i_cdc_fifo_gray_w (
.src_rst_ni,
.src_clk_i,
.src_data_i ( src_req_i.w ),
.src_valid_i ( src_req_i.w_valid ),
.src_ready_o ( src_resp_o.w_ready ),
.dst_rst_ni,
.dst_clk_i,
.dst_data_o ( dst_req_o.w ),
.dst_valid_o ( dst_req_o.w_valid ),
.dst_ready_i ( dst_resp_i.w_ready )
);
cdc_fifo_gray #(
.WIDTH ( $bits(b_chan_t) ),
.LOG_DEPTH ( LogDepth )
) i_cdc_fifo_gray_b (
.src_rst_ni ( dst_rst_ni ),
.src_clk_i ( dst_clk_i ),
.src_data_i ( dst_resp_i.b ),
.src_valid_i ( dst_resp_i.b_valid ),
.src_ready_o ( dst_req_o.b_ready ),
.dst_rst_ni ( src_rst_ni ),
.dst_clk_i ( src_clk_i ),
.dst_data_o ( src_resp_o.b ),
.dst_valid_o ( src_resp_o.b_valid ),
.dst_ready_i ( src_req_i.b_ready )
);
cdc_fifo_gray #(
.WIDTH ( $bits(ar_chan_t) ),
.LOG_DEPTH ( LogDepth )
) i_cdc_fifo_gray_ar (
.src_rst_ni,
.src_clk_i,
.src_data_i ( src_req_i.ar ),
.src_valid_i ( src_req_i.ar_valid ),
.src_ready_o ( src_resp_o.ar_ready ),
.dst_rst_ni,
.dst_clk_i,
.dst_data_o ( dst_req_o.ar ),
.dst_valid_o ( dst_req_o.ar_valid ),
.dst_ready_i ( dst_resp_i.ar_ready )
);
cdc_fifo_gray #(
.WIDTH ( $bits(r_chan_t) ),
.LOG_DEPTH ( LogDepth )
) i_cdc_fifo_gray_r (
.src_rst_ni ( dst_rst_ni ),
.src_clk_i ( dst_clk_i ),
.src_data_i ( dst_resp_i.r ),
.src_valid_i ( dst_resp_i.r_valid ),
.src_ready_o ( dst_req_o.r_ready ),
.dst_rst_ni ( src_rst_ni ),
.dst_clk_i ( src_clk_i ),
.dst_data_o ( src_resp_o.r ),
.dst_valid_o ( src_resp_o.r_valid ),
.dst_ready_i ( src_req_i.r_ready )
);
endmodule
`include "axi/assign.svh"
`include "axi/typedef.svh"
// interface wrapper
module axi_cdc_intf #(
parameter int unsigned AXI_ID_WIDTH = 0,
parameter int unsigned AXI_ADDR_WIDTH = 0,
parameter int unsigned AXI_DATA_WIDTH = 0,
parameter int unsigned AXI_USER_WIDTH = 0,
/// Depth of the FIFO crossing the clock domain, given as 2**LOG_DEPTH.
parameter int unsigned LOG_DEPTH = 1
) (
// slave side - clocked by `src_clk_i`
input logic src_clk_i,
input logic src_rst_ni,
AXI_BUS.Slave src,
// master side - clocked by `dst_clk_i`
input logic dst_clk_i,
input logic dst_rst_ni,
AXI_BUS.Master dst
);
typedef logic [AXI_ID_WIDTH-1:0] id_t;
typedef logic [AXI_ADDR_WIDTH-1:0] addr_t;
typedef logic [AXI_DATA_WIDTH-1:0] data_t;
typedef logic [AXI_DATA_WIDTH/8-1:0] strb_t;
typedef logic [AXI_USER_WIDTH-1:0] user_t;
`AXI_TYPEDEF_AW_CHAN_T(aw_chan_t, addr_t, id_t, user_t)
`AXI_TYPEDEF_W_CHAN_T(w_chan_t, data_t, strb_t, user_t)
`AXI_TYPEDEF_B_CHAN_T(b_chan_t, id_t, user_t)
`AXI_TYPEDEF_AR_CHAN_T(ar_chan_t, addr_t, id_t, user_t)
`AXI_TYPEDEF_R_CHAN_T(r_chan_t, data_t, id_t, user_t)
`AXI_TYPEDEF_REQ_T(req_t, aw_chan_t, w_chan_t, ar_chan_t)
`AXI_TYPEDEF_RESP_T(resp_t, b_chan_t, r_chan_t)
req_t src_req, dst_req;
resp_t src_resp, dst_resp;
`AXI_ASSIGN_TO_REQ(src_req, src)
`AXI_ASSIGN_FROM_RESP(src, src_resp)
`AXI_ASSIGN_FROM_REQ(dst, dst_req)
`AXI_ASSIGN_TO_RESP(dst_resp, dst)
axi_cdc #(
.aw_chan_t ( aw_chan_t ),
.w_chan_t ( w_chan_t ),
.b_chan_t ( b_chan_t ),
.ar_chan_t ( ar_chan_t ),
.r_chan_t ( r_chan_t ),
.axi_req_t ( req_t ),
.axi_resp_t ( resp_t ),
.LogDepth ( LOG_DEPTH )
) i_axi_cdc (
.src_clk_i,
.src_rst_ni,
.src_req_i ( src_req ),
.src_resp_o ( src_resp ),
.dst_clk_i,
.dst_rst_ni,
.dst_req_o ( dst_req ),
.dst_resp_i ( dst_resp )
);
endmodule
module axi_lite_cdc_intf #(
parameter int unsigned AXI_ADDR_WIDTH = 0,
parameter int unsigned AXI_DATA_WIDTH = 0,
/// Depth of the FIFO crossing the clock domain, given as 2**LOG_DEPTH.
parameter int unsigned LOG_DEPTH = 1
) (
// slave side - clocked by `src_clk_i`
input logic src_clk_i,
input logic src_rst_ni,
AXI_LITE.Slave src,
// master side - clocked by `dst_clk_i`
input logic dst_clk_i,
input logic dst_rst_ni,
AXI_LITE.Master dst
);
typedef logic [AXI_ADDR_WIDTH-1:0] addr_t;
typedef logic [AXI_DATA_WIDTH-1:0] data_t;
typedef logic [AXI_DATA_WIDTH/8-1:0] strb_t;
`AXI_LITE_TYPEDEF_AW_CHAN_T(aw_chan_t, addr_t)
`AXI_LITE_TYPEDEF_W_CHAN_T(w_chan_t, data_t, strb_t)
`AXI_LITE_TYPEDEF_B_CHAN_T(b_chan_t)
`AXI_LITE_TYPEDEF_AR_CHAN_T(ar_chan_t, addr_t)
`AXI_LITE_TYPEDEF_R_CHAN_T(r_chan_t, data_t)
`AXI_LITE_TYPEDEF_REQ_T(req_t, aw_chan_t, w_chan_t, ar_chan_t)
`AXI_LITE_TYPEDEF_RESP_T(resp_t, b_chan_t, r_chan_t)
req_t src_req, dst_req;
resp_t src_resp, dst_resp;
`AXI_LITE_ASSIGN_TO_REQ(src_req, src)
`AXI_LITE_ASSIGN_FROM_RESP(src, src_resp)
`AXI_LITE_ASSIGN_FROM_REQ(dst, dst_req)
`AXI_LITE_ASSIGN_TO_RESP(dst_resp, dst)
axi_cdc #(
.aw_chan_t ( aw_chan_t ),
.w_chan_t ( w_chan_t ),
.b_chan_t ( b_chan_t ),
.ar_chan_t ( ar_chan_t ),
.r_chan_t ( r_chan_t ),
.axi_req_t ( req_t ),
.axi_resp_t ( resp_t ),
.LogDepth ( LOG_DEPTH )
) i_axi_cdc (
.src_clk_i,
.src_rst_ni,
.src_req_i ( src_req ),
.src_resp_o ( src_resp ),
.dst_clk_i,
.dst_rst_ni,
.dst_req_o ( dst_req ),
.dst_resp_i ( dst_resp )
);
endmodule