tinyriscv/rtl/core/rib.v

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/*
Copyright 2020 Blue Liang, liangkangnan@163.com
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.
*/
`include "defines.v"
// RIB总线模块
module rib(
input wire clk,
input wire rst,
// master 0 interface
input wire[`MemAddrBus] m0_addr_i, // 主设备0读、写地址
input wire[`MemBus] m0_data_i, // 主设备0写数据
output reg[`MemBus] m0_data_o, // 主设备0读取到的数据
input wire m0_req_i, // 主设备0访问请求标志
input wire m0_we_i, // 主设备0写标志
// master 1 interface
input wire[`MemAddrBus] m1_addr_i, // 主设备1读、写地址
input wire[`MemBus] m1_data_i, // 主设备1写数据
output reg[`MemBus] m1_data_o, // 主设备1读取到的数据
input wire m1_req_i, // 主设备1访问请求标志
input wire m1_we_i, // 主设备1写标志
// master 2 interface
input wire[`MemAddrBus] m2_addr_i, // 主设备2读、写地址
input wire[`MemBus] m2_data_i, // 主设备2写数据
output reg[`MemBus] m2_data_o, // 主设备2读取到的数据
input wire m2_req_i, // 主设备2访问请求标志
input wire m2_we_i, // 主设备2写标志
// master 3 interface
input wire[`MemAddrBus] m3_addr_i, // 主设备3读、写地址
input wire[`MemBus] m3_data_i, // 主设备3写数据
output reg[`MemBus] m3_data_o, // 主设备3读取到的数据
input wire m3_req_i, // 主设备3访问请求标志
input wire m3_we_i, // 主设备3写标志
// slave 0 interface
output reg[`MemAddrBus] s0_addr_o, // 从设备0读、写地址
output reg[`MemBus] s0_data_o, // 从设备0写数据
input wire[`MemBus] s0_data_i, // 从设备0读取到的数据
output reg s0_we_o, // 从设备0写标志
// slave 1 interface
output reg[`MemAddrBus] s1_addr_o, // 从设备1读、写地址
output reg[`MemBus] s1_data_o, // 从设备1写数据
input wire[`MemBus] s1_data_i, // 从设备1读取到的数据
output reg s1_we_o, // 从设备1写标志
// slave 2 interface
output reg[`MemAddrBus] s2_addr_o, // 从设备2读、写地址
output reg[`MemBus] s2_data_o, // 从设备2写数据
input wire[`MemBus] s2_data_i, // 从设备2读取到的数据
output reg s2_we_o, // 从设备2写标志
// slave 3 interface
output reg[`MemAddrBus] s3_addr_o, // 从设备3读、写地址
output reg[`MemBus] s3_data_o, // 从设备3写数据
input wire[`MemBus] s3_data_i, // 从设备3读取到的数据
output reg s3_we_o, // 从设备3写标志
// slave 4 interface
output reg[`MemAddrBus] s4_addr_o, // 从设备4读、写地址
output reg[`MemBus] s4_data_o, // 从设备4写数据
input wire[`MemBus] s4_data_i, // 从设备4读取到的数据
output reg s4_we_o, // 从设备4写标志
// slave 5 interface
output reg[`MemAddrBus] s5_addr_o, // 从设备5读、写地址
output reg[`MemBus] s5_data_o, // 从设备5写数据
input wire[`MemBus] s5_data_i, // 从设备5读取到的数据
output reg s5_we_o, // 从设备5写标志
output reg hold_flag_o // 暂停流水线标志
);
// 访问地址的最高4位决定要访问的是哪一个从设备
// 因此最多支持16个从设备
parameter [3:0]slave_0 = 4'b0000;
parameter [3:0]slave_1 = 4'b0001;
parameter [3:0]slave_2 = 4'b0010;
parameter [3:0]slave_3 = 4'b0011;
parameter [3:0]slave_4 = 4'b0100;
parameter [3:0]slave_5 = 4'b0101;
parameter [1:0]grant0 = 2'h0;
parameter [1:0]grant1 = 2'h1;
parameter [1:0]grant2 = 2'h2;
parameter [1:0]grant3 = 2'h3;
wire[3:0] req;
reg[1:0] grant;
// 主设备请求信号
assign req = {m3_req_i, m2_req_i, m1_req_i, m0_req_i};
// 仲裁逻辑
// 固定优先级仲裁机制
// 优先级由高到低主设备3主设备0主设备2主设备1
always @ (*) begin
if (req[3]) begin
grant = grant3;
hold_flag_o = `HoldEnable;
end else if (req[0]) begin
grant = grant0;
hold_flag_o = `HoldEnable;
end else if (req[2]) begin
grant = grant2;
hold_flag_o = `HoldEnable;
end else begin
grant = grant1;
hold_flag_o = `HoldDisable;
end
end
// 根据仲裁结果,选择(访问)对应的从设备
always @ (*) begin
m0_data_o = `ZeroWord;
m1_data_o = `INST_NOP;
m2_data_o = `ZeroWord;
m3_data_o = `ZeroWord;
s0_addr_o = `ZeroWord;
s1_addr_o = `ZeroWord;
s2_addr_o = `ZeroWord;
s3_addr_o = `ZeroWord;
s4_addr_o = `ZeroWord;
s5_addr_o = `ZeroWord;
s0_data_o = `ZeroWord;
s1_data_o = `ZeroWord;
s2_data_o = `ZeroWord;
s3_data_o = `ZeroWord;
s4_data_o = `ZeroWord;
s5_data_o = `ZeroWord;
s0_we_o = `WriteDisable;
s1_we_o = `WriteDisable;
s2_we_o = `WriteDisable;
s3_we_o = `WriteDisable;
s4_we_o = `WriteDisable;
s5_we_o = `WriteDisable;
case (grant)
grant0: begin
case (m0_addr_i[31:28])
slave_0: begin
s0_we_o = m0_we_i;
s0_addr_o = {{4'h0}, {m0_addr_i[27:0]}};
s0_data_o = m0_data_i;
m0_data_o = s0_data_i;
end
slave_1: begin
s1_we_o = m0_we_i;
s1_addr_o = {{4'h0}, {m0_addr_i[27:0]}};
s1_data_o = m0_data_i;
m0_data_o = s1_data_i;
end
slave_2: begin
s2_we_o = m0_we_i;
s2_addr_o = {{4'h0}, {m0_addr_i[27:0]}};
s2_data_o = m0_data_i;
m0_data_o = s2_data_i;
end
slave_3: begin
s3_we_o = m0_we_i;
s3_addr_o = {{4'h0}, {m0_addr_i[27:0]}};
s3_data_o = m0_data_i;
m0_data_o = s3_data_i;
end
slave_4: begin
s4_we_o = m0_we_i;
s4_addr_o = {{4'h0}, {m0_addr_i[27:0]}};
s4_data_o = m0_data_i;
m0_data_o = s4_data_i;
end
slave_5: begin
s5_we_o = m0_we_i;
s5_addr_o = {{4'h0}, {m0_addr_i[27:0]}};
s5_data_o = m0_data_i;
m0_data_o = s5_data_i;
end
default: begin
end
endcase
end
grant1: begin
case (m1_addr_i[31:28])
slave_0: begin
s0_we_o = m1_we_i;
s0_addr_o = {{4'h0}, {m1_addr_i[27:0]}};
s0_data_o = m1_data_i;
m1_data_o = s0_data_i;
end
slave_1: begin
s1_we_o = m1_we_i;
s1_addr_o = {{4'h0}, {m1_addr_i[27:0]}};
s1_data_o = m1_data_i;
m1_data_o = s1_data_i;
end
slave_2: begin
s2_we_o = m1_we_i;
s2_addr_o = {{4'h0}, {m1_addr_i[27:0]}};
s2_data_o = m1_data_i;
m1_data_o = s2_data_i;
end
slave_3: begin
s3_we_o = m1_we_i;
s3_addr_o = {{4'h0}, {m1_addr_i[27:0]}};
s3_data_o = m1_data_i;
m1_data_o = s3_data_i;
end
slave_4: begin
s4_we_o = m1_we_i;
s4_addr_o = {{4'h0}, {m1_addr_i[27:0]}};
s4_data_o = m1_data_i;
m1_data_o = s4_data_i;
end
slave_5: begin
s5_we_o = m1_we_i;
s5_addr_o = {{4'h0}, {m1_addr_i[27:0]}};
s5_data_o = m1_data_i;
m1_data_o = s5_data_i;
end
default: begin
end
endcase
end
grant2: begin
case (m2_addr_i[31:28])
slave_0: begin
s0_we_o = m2_we_i;
s0_addr_o = {{4'h0}, {m2_addr_i[27:0]}};
s0_data_o = m2_data_i;
m2_data_o = s0_data_i;
end
slave_1: begin
s1_we_o = m2_we_i;
s1_addr_o = {{4'h0}, {m2_addr_i[27:0]}};
s1_data_o = m2_data_i;
m2_data_o = s1_data_i;
end
slave_2: begin
s2_we_o = m2_we_i;
s2_addr_o = {{4'h0}, {m2_addr_i[27:0]}};
s2_data_o = m2_data_i;
m2_data_o = s2_data_i;
end
slave_3: begin
s3_we_o = m2_we_i;
s3_addr_o = {{4'h0}, {m2_addr_i[27:0]}};
s3_data_o = m2_data_i;
m2_data_o = s3_data_i;
end
slave_4: begin
s4_we_o = m2_we_i;
s4_addr_o = {{4'h0}, {m2_addr_i[27:0]}};
s4_data_o = m2_data_i;
m2_data_o = s4_data_i;
end
slave_5: begin
s5_we_o = m2_we_i;
s5_addr_o = {{4'h0}, {m2_addr_i[27:0]}};
s5_data_o = m2_data_i;
m2_data_o = s5_data_i;
end
default: begin
end
endcase
end
grant3: begin
case (m3_addr_i[31:28])
slave_0: begin
s0_we_o = m3_we_i;
s0_addr_o = {{4'h0}, {m3_addr_i[27:0]}};
s0_data_o = m3_data_i;
m3_data_o = s0_data_i;
end
slave_1: begin
s1_we_o = m3_we_i;
s1_addr_o = {{4'h0}, {m3_addr_i[27:0]}};
s1_data_o = m3_data_i;
m3_data_o = s1_data_i;
end
slave_2: begin
s2_we_o = m3_we_i;
s2_addr_o = {{4'h0}, {m3_addr_i[27:0]}};
s2_data_o = m3_data_i;
m3_data_o = s2_data_i;
end
slave_3: begin
s3_we_o = m3_we_i;
s3_addr_o = {{4'h0}, {m3_addr_i[27:0]}};
s3_data_o = m3_data_i;
m3_data_o = s3_data_i;
end
slave_4: begin
s4_we_o = m3_we_i;
s4_addr_o = {{4'h0}, {m3_addr_i[27:0]}};
s4_data_o = m3_data_i;
m3_data_o = s4_data_i;
end
slave_5: begin
s5_we_o = m3_we_i;
s5_addr_o = {{4'h0}, {m3_addr_i[27:0]}};
s5_data_o = m3_data_i;
m3_data_o = s5_data_i;
end
default: begin
end
endcase
end
default: begin
end
endcase
end
endmodule