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axi4: Deinterleaver need not make a Q for an unused AXI id

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This commit is contained in:
Wesley W. Terpstra 2017-06-23 16:01:31 -07:00
parent 9bea7c1c58
commit feecfb53ed
1 changed files with 35 additions and 23 deletions
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58
src/main/scala/uncore/axi4/Deinterleaver.scala
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@ -28,7 +28,7 @@ class AXI4Deinterleaver(maxReadBytes: Int)(implicit p: Parameters) extends LazyM
}
((io.in zip io.out) zip (node.edgesIn zip node.edgesOut)) foreach { case ((in, out), (edgeIn, edgeOut)) =>
val queues = edgeOut.master.endId
val endId = edgeOut.master.endId
val beatBytes = edgeOut.slave.beatBytes
val beats = (maxReadBytes+beatBytes-1) / beatBytes
@ -42,31 +42,43 @@ class AXI4Deinterleaver(maxReadBytes: Int)(implicit p: Parameters) extends LazyM
// Nothing to do if only single-beat R
in.r <> out.r
} else {
// Buffer R response
val count = RegInit(Vec.fill(queues) { UInt(0, width=log2Ceil(beats+1)) })
val qs = Seq.fill(queues) { Module(new Queue(out.r.bits, beats)) }
// Queues to buffer R responses
val qs = Seq.tabulate(endId) { i =>
val depth = edgeOut.master.masters.find(_.id.contains(i)).flatMap(_.maxFlight).getOrElse(0)
if (depth > 0) {
Module(new Queue(out.r.bits, beats)).io
} else {
Wire(new QueueIO(out.r.bits, beats))
}
}
// Which ID is being enqueued and dequeued?
val locked = RegInit(Bool(false))
val deq_id = Reg(UInt(width=log2Up(queues)))
val deq_id = Reg(UInt(width=log2Up(endId)))
val enq_id = out.r.bits.id
val deq_OH = UIntToOH(deq_id, queues)
val enq_OH = UIntToOH(enq_id, queues)
val deq_OH = UIntToOH(deq_id, endId)
val enq_OH = UIntToOH(enq_id, endId)
// Track the number of completely received bursts per FIFO id
val next_count = Wire(count)
((count zip next_count) zip (enq_OH.toBools zip deq_OH.toBools)) foreach { case ((p, n), (i, d)) =>
val inc = i && out.r.fire() && out.r.bits.last
val dec = d && in.r.fire() && in.r.bits.last
n := p + inc.asUInt - dec.asUInt
// Bounds checking
assert (!dec || p =/= UInt(0))
assert (!inc || p =/= UInt(beats))
}
count := next_count
val pending = Cat(Seq.tabulate(endId) { i =>
val depth = edgeOut.master.masters.find(_.id.contains(i)).flatMap(_.maxFlight).getOrElse(0)
if (depth == 0) {
Bool(false)
} else {
val count = RegInit(UInt(0, width=log2Ceil(beats+1)))
val next = Wire(count)
val inc = enq_OH(i) && out.r.fire() && out.r.bits.last
val dec = deq_OH(i) && in.r.fire() && in.r.bits.last
next := count + inc.asUInt - dec.asUInt
count := next
// Bounds checking
assert (!dec || count =/= UInt(0))
assert (!inc || count =/= UInt(beats))
next =/= UInt(0)
}
}.reverse)
// Select which Q will we start sending next cycle
val pending = Cat(next_count.map(_ =/= UInt(0)).reverse)
val winner = pending & ~(leftOR(pending) << 1)
when (!locked || (in.r.fire() && in.r.bits.last)) {
locked := pending.orR
@ -75,16 +87,16 @@ class AXI4Deinterleaver(maxReadBytes: Int)(implicit p: Parameters) extends LazyM
// Transmit the selected burst to inner
in.r.valid := locked
in.r.bits := Vec(qs.map(_.io.deq.bits))(deq_id)
in.r.bits := Vec(qs.map(_.deq.bits))(deq_id)
(deq_OH.toBools zip qs) foreach { case (s, q) =>
q.io.deq.ready := s && in.r.fire()
q.deq.ready := s && in.r.fire()
}
// Feed response into matching Q
out.r.ready := Vec(qs.map(_.io.enq.ready))(enq_id)
out.r.ready := Vec(qs.map(_.enq.ready))(enq_id)
(enq_OH.toBools zip qs) foreach { case (s, q) =>
q.io.enq.valid := s && out.r.valid
q.io.enq.bits := out.r.bits
q.enq.valid := s && out.r.valid
q.enq.bits := out.r.bits
}
}
}