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rocket-chip/rocket/src/main/scala/arbiter.scala

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Scala
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// See LICENSE for license details.
package rocket
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import Chisel._
import uncore._
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import cde.{Parameters, Field}
import junctions.{ParameterizedBundle, DecoupledHelper}
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class HellaCacheArbiter(n: Int)(implicit p: Parameters) extends Module
{
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val io = new Bundle {
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val requestor = Vec(n, new HellaCacheIO).flip
val mem = new HellaCacheIO
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}
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val r_valid = io.requestor.map(r => Reg(next=r.req.valid))
io.mem.req.valid := io.requestor.map(_.req.valid).reduce(_||_)
io.requestor(0).req.ready := io.mem.req.ready
for (i <- 1 until n)
io.requestor(i).req.ready := io.requestor(i-1).req.ready && !io.requestor(i-1).req.valid
io.mem.req.bits := io.requestor(n-1).req.bits
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io.mem.req.bits.tag := Cat(io.requestor(n-1).req.bits.tag, UInt(n-1, log2Up(n)))
for (i <- n-2 to 0 by -1) {
val req = io.requestor(i).req
when (req.valid) {
io.mem.req.bits.cmd := req.bits.cmd
io.mem.req.bits.typ := req.bits.typ
io.mem.req.bits.addr := req.bits.addr
io.mem.req.bits.phys := req.bits.phys
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io.mem.req.bits.tag := Cat(req.bits.tag, UInt(i, log2Up(n)))
}
when (r_valid(i)) {
io.mem.req.bits.kill := req.bits.kill
io.mem.req.bits.data := req.bits.data
}
}
for (i <- 0 until n) {
val resp = io.requestor(i).resp
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val tag_hit = io.mem.resp.bits.tag(log2Up(n)-1,0) === UInt(i)
resp.valid := io.mem.resp.valid && tag_hit
io.requestor(i).xcpt := io.mem.xcpt
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io.requestor(i).ordered := io.mem.ordered
resp.bits := io.mem.resp.bits
resp.bits.tag := io.mem.resp.bits.tag >> log2Up(n)
resp.bits.nack := io.mem.resp.bits.nack && tag_hit
resp.bits.replay := io.mem.resp.bits.replay && tag_hit
io.requestor(i).replay_next.valid := io.mem.replay_next.valid &&
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io.mem.replay_next.bits(log2Up(n)-1,0) === UInt(i)
io.requestor(i).replay_next.bits := io.mem.replay_next.bits >> log2Up(n)
}
}
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class InOrderArbiter[T <: Data, U <: Data](reqTyp: T, respTyp: U, n: Int)
(implicit p: Parameters) extends Module {
val io = new Bundle {
val in_req = Vec(n, Decoupled(reqTyp)).flip
val in_resp = Vec(n, Decoupled(respTyp))
val out_req = Decoupled(reqTyp)
val out_resp = Decoupled(respTyp).flip
}
if (n > 1) {
val route_q = Module(new Queue(UInt(width = log2Up(n)), 2))
val req_arb = Module(new RRArbiter(reqTyp, n))
req_arb.io.in <> io.in_req
val req_helper = DecoupledHelper(
req_arb.io.out.valid,
route_q.io.enq.ready,
io.out_req.ready)
io.out_req.bits := req_arb.io.out.bits
io.out_req.valid := req_helper.fire(io.out_req.ready)
route_q.io.enq.bits := req_arb.io.chosen
route_q.io.enq.valid := req_helper.fire(route_q.io.enq.ready)
req_arb.io.out.ready := req_helper.fire(req_arb.io.out.valid)
val resp_sel = route_q.io.deq.bits
val resp_ready = io.in_resp(resp_sel).ready
val resp_helper = DecoupledHelper(
resp_ready,
route_q.io.deq.valid,
io.out_resp.valid)
val resp_valid = resp_helper.fire(resp_ready)
for (i <- 0 until n) {
io.in_resp(i).bits := io.out_resp.bits
io.in_resp(i).valid := resp_valid && resp_sel === UInt(i)
}
route_q.io.deq.ready := resp_helper.fire(route_q.io.deq.valid)
io.out_resp.ready := resp_helper.fire(io.out_resp.valid)
} else {
io.out_req <> io.in_req.head
io.in_resp.head <> io.out_resp
}
}