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tilelink2 Broadcast: add special case handling for 0 cached clients

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This commit is contained in:
Wesley W. Terpstra 2016-11-03 21:55:54 -07:00
parent ba3c83287f
commit 0f3947bb86
1 changed files with 16 additions and 13 deletions
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27
src/main/scala/uncore/tilelink2/Broadcast.scala
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@ -67,7 +67,7 @@ class TLBroadcast(lineBytes: Int, numTrackers: Int = 4) extends LazyModule
require (lineBytes >= edgeOut.manager.beatBytes) require (lineBytes >= edgeOut.manager.beatBytes)
// For the probe walker, we need to identify all the caches // For the probe walker, we need to identify all the caches
val caches = clients.filter(_.supportsProbe).map(_.sourceId) val caches = clients.filter(_.supportsProbe).map(_.sourceId)
val cache_targets = Vec(caches.map(c => UInt(c.start))) val cache_targets = caches.map(c => UInt(c.start))
// Create the request tracker queues // Create the request tracker queues
val trackers = Seq.tabulate(numTrackers) { id => val trackers = Seq.tabulate(numTrackers) { id =>
@ -81,7 +81,7 @@ class TLBroadcast(lineBytes: Int, numTrackers: Int = 4) extends LazyModule
} }
// Depending on the high source bits, we might transform D // Depending on the high source bits, we might transform D
val d_high = 1 << log2Ceil(edgeIn.client.endSourceId) val d_high = log2Ceil(edgeIn.client.endSourceId)
val d_what = out.d.bits.source(d_high+1, d_high) val d_what = out.d.bits.source(d_high+1, d_high)
val d_drop = d_what === DROP val d_drop = d_what === DROP
val d_hasData = edgeOut.hasData(out.d.bits) val d_hasData = edgeOut.hasData(out.d.bits)
@ -143,20 +143,22 @@ class TLBroadcast(lineBytes: Int, numTrackers: Int = 4) extends LazyModule
trackers.map { t => (edgeOut.numBeats1(t.out_a.bits), t.out_a) }):_*) trackers.map { t => (edgeOut.numBeats1(t.out_a.bits), t.out_a) }):_*)
// The Probe FSM walks all caches and probes them // The Probe FSM walks all caches and probes them
val probe_todo = RegInit(UInt(0, width = caches.size)) val probe_todo = RegInit(UInt(0, width = max(1, caches.size)))
val probe_line = Reg(UInt()) val probe_line = Reg(UInt())
val probe_perms = Reg(UInt(width = 2)) val probe_perms = Reg(UInt(width = 2))
val probe_next = probe_todo & ~(leftOR(probe_todo) << 1) val probe_next = probe_todo & ~(leftOR(probe_todo) << 1)
val probe_busy = probe_todo.orR() val probe_busy = probe_todo.orR()
val probe_target = Mux1H(probe_next, cache_targets) val probe_target = if (caches.size == 0) UInt(0) else Mux1H(probe_next, cache_targets)
// Probe whatever the FSM wants to do next // Probe whatever the FSM wants to do next
in.b.valid := probe_busy in.b.valid := probe_busy
if (caches.size != 0) {
in.b.bits := edgeIn.Probe(probe_line << lineShift, probe_target, UInt(lineShift), probe_perms)._2 in.b.bits := edgeIn.Probe(probe_line << lineShift, probe_target, UInt(lineShift), probe_perms)._2
}
when (in.b.fire()) { probe_todo := probe_todo & ~probe_next } when (in.b.fire()) { probe_todo := probe_todo & ~probe_next }
// Which cache does a request come from? // Which cache does a request come from?
val a_cache = Vec(caches.map(_.contains(in.a.bits.source))).asUInt val a_cache = if (caches.size == 0) UInt(1) else Vec(caches.map(_.contains(in.a.bits.source))).asUInt
val (a_first, _, _) = edgeIn.firstlast(in.a) val (a_first, _, _) = edgeIn.firstlast(in.a)
// To accept a request from A, the probe FSM must be idle and there must be a matching tracker // To accept a request from A, the probe FSM must be idle and there must be a matching tracker
@ -173,7 +175,7 @@ class TLBroadcast(lineBytes: Int, numTrackers: Int = 4) extends LazyModule
t.in_a.valid := in.a.valid && select && (!a_first || !probe_busy) t.in_a.valid := in.a.valid && select && (!a_first || !probe_busy)
t.in_a.bits := in.a.bits t.in_a.bits := in.a.bits
t.in_a_first := a_first t.in_a_first := a_first
t.probe := Mux(a_cache.orR(), UInt(caches.size-1), UInt(caches.size)) t.probe := (if (caches.size == 0) UInt(0) else Mux(a_cache.orR(), UInt(caches.size-1), UInt(caches.size)))
} }
when (in.a.fire() && a_first) { when (in.a.fire() && a_first) {
@ -256,12 +258,7 @@ class TLBroadcastTracker(id: Int, lineBytes: Int, probeCountBits: Int, edgeIn: T
io.source := source io.source := source
io.line := address >> lineShift io.line := address >> lineShift
class Data extends Bundle { val i_data = Wire(Decoupled(new TLBroadcastData(edgeIn.bundle)))
val mask = io.in_a.bits.mask.cloneType
val data = io.in_a.bits.data.cloneType
}
val i_data = Wire(Decoupled(new Data))
val o_data = Queue(i_data, lineBytes / edgeIn.manager.beatBytes) val o_data = Queue(i_data, lineBytes / edgeIn.manager.beatBytes)
io.in_a.ready := (idle || !io.in_a_first) && i_data.ready io.in_a.ready := (idle || !io.in_a_first) && i_data.ready
@ -295,3 +292,9 @@ object TLBroadcastConstants
val DROP = UInt(1) val DROP = UInt(1)
val PASS = UInt(0) val PASS = UInt(0)
} }
class TLBroadcastData(params: TLBundleParameters) extends TLBundleBase(params)
{
val mask = UInt(width = params.dataBits/8)
val data = UInt(width = params.dataBits)
}