blob: af83b076c6083fd2073555c4688a5acdb38fa7da [file] [log] [blame]
// SPDX-FileCopyrightText: 2020 Muhammad Hadir Khan
// 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
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.
// SPDX-License-Identifier: Apache-2.0
package merl.uit.tilelink
import chisel3._
import chisel3.stage.{ChiselGeneratorAnnotation, ChiselStage}
object Arbiter extends App {
implicit val conf: TLConfiguration = TLConfiguration()
(new ChiselStage).execute(args, Seq(ChiselGeneratorAnnotation(() => new Arbiter(3))))
class Arbiter(M: Int)(implicit val conf: TLConfiguration) extends Module {
val io = IO(new Bundle {
val req_i = Input(Vec(M, Bool())) // a_valid signals coming from all the hosts
val data_i = Vec(M, Flipped(new TL_H2D)) // Channel A data coming from all the hosts
val gnt_o = Output(Vec(M, Bool())) // The grant output used for indicating the host that the device is ready to accept the request
val valid_o = Output(Bool()) // The valid signal from the host to the device
val data_o = new TL_H2D // The Channel A data of selected host forwarded to the device
val ready_i = Input(Bool()) // The ready signal coming from the device
// by default setting the arbiter to pass the request of last host
io.data_o <> io.data_i(M-1)
io.valid_o := io.req_i(M-1)
io.gnt_o(M-1) := Mux(io.ready_i, Mux(io.req_i(M-1), true.B, false.B), false.B)
for(i <- M-2 to 0 by -1) {
when(io.req_i(i)) {
io.gnt_o(i) := Mux(io.ready_i, true.B, false.B)
io.data_o := io.data_i(i)
io.valid_o := io.req_i(i)
} .otherwise {
io.gnt_o(i) := false.B