From aac77b3d74c6033eb03f9055a2304bd645529db8 Mon Sep 17 00:00:00 2001
From: Jerry Zhao <jerryz123@berkeley.edu>
Date: Wed, 10 Mar 2021 14:46:53 -0800
Subject: [PATCH] Move TileResetCtrl before the ResetSynchronizers, and give
 them an async reset

---
 generators/chipyard/src/main/scala/Clocks.scala | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/generators/chipyard/src/main/scala/Clocks.scala b/generators/chipyard/src/main/scala/Clocks.scala
index 9ca6a801..e29f8392 100644
--- a/generators/chipyard/src/main/scala/Clocks.scala
+++ b/generators/chipyard/src/main/scala/Clocks.scala
@@ -70,16 +70,16 @@ object ClockingSchemeGenerators {
 
     // Add a control register for each tile's reset
     val resetSetter = chiptop.lazySystem match {
-      case sys: BaseSubsystem with InstantiatesTiles => TLTileResetCtrl(sys)
-      case _ => ClockGroupEphemeralNode()
+      case sys: BaseSubsystem with InstantiatesTiles => Some(TLTileResetCtrl(sys))
+      case _ => None
     }
+    val resetSetterResetProvider = resetSetter.map(_.tileResetProviderNode).getOrElse(ClockGroupEphemeralNode())
 
     val aggregator = LazyModule(new ClockGroupAggregator("allClocks")).node
     (chiptop.implicitClockSinkNode
       := ClockGroup()
       := aggregator)
     (systemAsyncClockGroup
-      :*= resetSetter
       :*= ClockGroupNamePrefixer()
       :*= aggregator)
 
@@ -87,10 +87,16 @@ object ClockingSchemeGenerators {
     (aggregator
       := ClockGroupFrequencySpecifier(p(ClockFrequencyAssignersKey), p(DefaultClockFrequencyKey))
       := ClockGroupResetSynchronizer()
+      := resetSetterResetProvider
       := DividerOnlyClockGenerator()
       := referenceClockSource)
 
 
+    val asyncResetBroadcast = FixedClockBroadcast(None)
+    resetSetter.foreach(_.asyncResetSinkNode := asyncResetBroadcast)
+    val asyncResetSource = ClockSourceNode(Seq(ClockSourceParameters()))
+    asyncResetBroadcast := asyncResetSource
+
     InModuleBody {
       val clock_wire = Wire(Input(Clock()))
       val reset_wire = GenerateReset(chiptop, clock_wire)
@@ -102,6 +108,11 @@ object ClockingSchemeGenerators {
         o.reset := reset_wire
       }
 
+      asyncResetSource.out.unzip._1.map { o =>
+        o.clock := false.B.asClock // async reset broadcast network does not provide a clock
+        o.reset := reset_wire
+      }
+
       chiptop.harnessFunctions += ((th: HasHarnessSignalReferences) => {
         clock_io := th.harnessClock
         Nil })