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tilelink2: fix Xbar bug where Mux1H broke FSM if only one manager

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This commit is contained in:
Wesley W. Terpstra 2016-09-04 18:40:19 -07:00
parent a0c25880c7
commit 0faa8c4051
1 changed files with 10 additions and 3 deletions
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11
src/main/scala/uncore/tilelink2/Xbar.scala
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@ -148,7 +148,7 @@ class TLXbar(policy: (Vec[Bool], Bool) => Seq[Bool] = TLXbar.lowestIndex) extend
val requestAIO = Vec(in.map { i => Vec(node.edgesOut.map { o => i.a.valid && o.manager.contains(i.a.bits.address) }) })
val requestBOI = Vec(out.map { o => Vec(inputIdRanges.map { i => o.b.valid && i .contains(o.b.bits.source) }) })
val requestCIO = Vec(in.map { i => Vec(node.edgesOut.map { o => i.c.valid && o.manager.contains(i.c.bits.address) }) })
val requestDOI = Vec(out.map { o => Vec(inputIdRanges.map { i => o.d.valid && i .contains(o.b.bits.source) }) })
val requestDOI = Vec(out.map { o => Vec(inputIdRanges.map { i => o.d.valid && i .contains(o.d.bits.source) }) })
val requestEIO = Vec(in.map { i => Vec(outputIdRanges.map { o => i.e.valid && o .contains(i.e.bits.sink) }) })
val beatsA = Vec((in zip node.edgesIn) map { case (i, e) => e.numBeats(i.a.bits) })
@ -191,8 +191,15 @@ class TLXbar(policy: (Vec[Bool], Bool) => Seq[Bool] = TLXbar.lowestIndex) extend
// Apply policy to select which requester wins
val winners = Vec(policy(requests, idle))
// Winners must be a subset of requests
assert ((winners zip requests).map { case (w,r) => !w || r } .reduce(_ && _))
// There must be only one winner
val prefixOR = winners.scanLeft(Bool(false))(_ || _).init
assert ((prefixOR zip winners).map { case (p,w) => !p || !w }.reduce(_ && _))
// Supposing we take the winner as input, how many beats must be sent?
val initBeats = Mux1H(winners, beats)
val maskedBeats = (winners zip beats).map { case (w,b) => Mux(w, b, UInt(0)) }
val initBeats = maskedBeats.reduceLeft(_ | _) // no winner => 0 beats
// What is the counter state before progress?
val todoBeats = Mux(idle, initBeats, beatsLeft)
// Apply progress and register the result