Pass ClockCrossingType into DCache; use it instead of knownRatio

src/main/scala/groundtest/Tile.scala

@@ -40,7 +40,7 @@ abstract class GroundTestTile(params: GroundTestTileParams)
   val haltNode: IntOutwardNode = IntIdentityNode()
   val wfiNode: IntOutwardNode = IntIdentityNode()
 
-  val dcacheOpt = params.dcache.map { dc => LazyModule(new DCache(0)) }
+  val dcacheOpt = params.dcache.map { dc => LazyModule(new DCache(0, crossing)) }
 
   override lazy val module = new GroundTestTileModuleImp(this)
 }

src/main/scala/rocket/DCache.scala

@@ -5,7 +5,7 @@ package freechips.rocketchip.rocket
 import Chisel._
 import Chisel.ImplicitConversions._
 import freechips.rocketchip.config.Parameters
-import freechips.rocketchip.diplomacy.{AddressSet, RegionType}
+import freechips.rocketchip.diplomacy._
 import freechips.rocketchip.tile.LookupByHartId
 import freechips.rocketchip.tilelink._
 import freechips.rocketchip.util._
@@ -79,7 +79,7 @@ class DCacheMetadataReq(implicit p: Parameters) extends L1HellaCacheBundle()(p)
   val data = UInt(width = cacheParams.tagCode.width(new L1Metadata().getWidth))
 }
 
-class DCache(hartid: Int, val bufferUncachedRequests: Option[Int] = None)(implicit p: Parameters) extends HellaCache(hartid)(p) {
+class DCache(hartid: Int, val crossing: ClockCrossingType)(implicit p: Parameters) extends HellaCache(hartid)(p) {
   override lazy val module = new DCacheModule(this)
 }
 
@@ -121,10 +121,13 @@ class DCacheModule(outer: DCache) extends HellaCacheModule(outer) {
   metaArb.io.out.ready := clock_en_reg
 
   val tl_out_a = Wire(tl_out.a)
-  tl_out.a <> outer.bufferUncachedRequests
-                .map(_ min maxUncachedInFlight-1)
-                .map(Queue(tl_out_a, _, flow = true))
-                .getOrElse(tl_out_a)
+  tl_out.a <> {
+    val a_queue_depth = outer.crossing match {
+      case RationalCrossing(_) => 2 min maxUncachedInFlight-1 // TODO make this depend on the actual ratio?
+      case SynchronousCrossing(_) => 0
+    }
+    Queue(tl_out_a, a_queue_depth, flow = true)
+  }
 
   val (tl_out_c, release_queue_empty) =
     if (cacheParams.acquireBeforeRelease) {
@@ -851,8 +854,11 @@ class DCacheModule(outer: DCache) extends HellaCacheModule(outer) {
   io.cpu.perf.canAcceptLoadThenLoad := !((s1_valid && s1_write && needsRead(s1_req)) && ((s2_valid && s2_write && !s2_waw_hazard || pstore1_held) || pstore2_valid))
   io.cpu.perf.blocked := {
     // stop reporting blocked just before unblocking to avoid overly conservative stalling
-    val cycles = outer.bufferUncachedRequests.map(n => if (n > 1) 1 else 2).getOrElse(2)
-    cached_grant_wait && d_address_inc < ((cacheBlockBytes - cycles * beatBytes) max 0)
+    val beatsBeforeEnd = outer.crossing match {
+      case RationalCrossing(_) => 1 // assumes 1 < ratio <= 2; need more bookkeeping for optimal handling of >2
+      case SynchronousCrossing(_) => 2
+    }
+    cached_grant_wait && d_address_inc < ((cacheBlockBytes - beatsBeforeEnd * beatBytes) max 0)
   }
 
   // report errors

src/main/scala/rocket/HellaCache.scala

@@ -224,7 +224,7 @@ trait HasHellaCache { this: BaseTile =>
   var nDCachePorts = 0
   lazy val dcache: HellaCache = LazyModule(
     if(tileParams.dcache.get.nMSHRs == 0) {
-      new DCache(hartId, p(RocketCrossingKey).head.knownRatio)
+      new DCache(hartId, crossing)
     } else { new NonBlockingDCache(hartId) })
 
   tlMasterXbar.node := dcache.node