Fix wb dead lock

SpinalHDL · Mar 11, 2024 · 8984918 · 8984918
1 parent 72225c4
commit 8984918
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Showing 2 changed files with 9 additions and 4 deletions.
diff --git a/src/main/scala/vexiiriscv/execute/lsu/LsuL1Plugin.scala b/src/main/scala/vexiiriscv/execute/lsu/LsuL1Plugin.scala
@@ -792,6 +792,9 @@ class LsuL1Plugin(val lane : ExecuteLaneService,
         val loadDataHazard = LOAD && (bankNotRead || writeToReadHazard)
         val storeHazard = (STORE || FLUSH) && (!bankWriteReservation.win || !reservation.win)
 
+        // A few explanation : Some things have to be accurate, while some other can be deflected / ignored, especially
+        // when is need some shared ressources.
+        // For instance, a load miss may not trigger a refill, a flush may hit but may not trigger a flush
         val hazardReg = RegNext(this(HAZARD) && lane.isFreezed()) init(False)
         HAZARD := hazardReg || loadDataHazard || refillHazard || storeHazard
         MISS := !HAZARD && !WAYS_HIT && !FLUSH

diff --git a/src/main/scala/vexiiriscv/execute/lsu/LsuPlugin.scala b/src/main/scala/vexiiriscv/execute/lsu/LsuPlugin.scala
@@ -233,8 +233,8 @@ class LsuPlugin(var layer : LaneLayer,
 
       val holdHart = new Area{
         val wordPerLine = LsuL1.LINE_BYTES*8/XLEN
-        assert(storeBufferOps >= wordPerLine)
-        val waitIt = RegInit(False) clearWhen (slotsFree && ops.occupancy <= storeBufferOps - wordPerLine)
+        val threshold = Math.max(storeBufferOps - wordPerLine, storeBufferOps/2)
+        val waitIt = RegInit(False) clearWhen (slotsFree && ops.occupancy <= threshold)
         host[DispatchPlugin].haltDispatchWhen(waitIt)
       }
 
@@ -305,8 +305,10 @@ class LsuPlugin(var layer : LaneLayer,
       }
 
       val wb = withStoreBuffer generate new Area {
+        val isHead = storeBuffer.pop.ptr === storeBuffer.ops.freePtr
+        val flush = storeBuffer.waitL1.valid && !isHead
         val port = ports.addRet(Stream(LsuL1Cmd()))
-        port.valid := storeBuffer.pop.valid && !storeBuffer.waitL1.valid
+        port.valid := storeBuffer.pop.valid && !storeBuffer.waitL1.valid && !flush
         port.address := storeBuffer.pop.op.address.resized
         port.size := storeBuffer.pop.op.size
         port.load := False
@@ -315,7 +317,7 @@ class LsuPlugin(var layer : LaneLayer,
         port.fromFlush := False
         port.fromAccess := False
         port.fromStoreBuffer := True
-        storeBuffer.pop.ready := port.ready
+        storeBuffer.pop.ready := port.ready || flush
       }
 
       val arbiter = StreamArbiterFactory().noLock.lowerFirst.buildOn(ports)