1 files changed, 290 insertions, 0 deletions
diff --git a/VexRiscv/src/main/scala/vexriscv/plugin/IBusCachedPlugin.scala b/VexRiscv/src/main/scala/vexriscv/plugin/IBusCachedPlugin.scala
new file mode 100644
index 0000000..035c5dc
--- /dev/null
+++ b/VexRiscv/src/main/scala/vexriscv/plugin/IBusCachedPlugin.scala
@@ -0,0 +1,290 @@
+package vexriscv.plugin
+
+import vexriscv.{plugin, _}
+import vexriscv.ip._
+import spinal.core._
+import spinal.lib._
+
+import scala.collection.mutable.ArrayBuffer
+
+//class IBusCachedPlugin(config : InstructionCacheConfig, memoryTranslatorPortConfig : Any = null) extends Plugin[VexRiscv] {
+//  var iBus  : InstructionCacheMemBus = null
+//  override def build(pipeline: VexRiscv): Unit = ???
+//}
+
+case class TightlyCoupledBus() extends Bundle with IMasterSlave {
+  val enable = Bool()
+  val address = UInt(32 bits)
+  val data = Bits(32 bits)
+
+  override def asMaster(): Unit = {
+    out(enable, address)
+    in(data)
+  }
+}
+
+case class TightlyCoupledPortParameter(name : String, hit : UInt => Bool)
+case class TightlyCoupledPort(p : TightlyCoupledPortParameter, var bus : TightlyCoupledBus)
+class IBusCachedPlugin(resetVector : BigInt = 0x80000000l,
+                       relaxedPcCalculation : Boolean = false,
+                       prediction : BranchPrediction = NONE,
+                       historyRamSizeLog2 : Int = 10,
+                       compressedGen : Boolean = false,
+                       keepPcPlus4 : Boolean = false,
+                       val config : InstructionCacheConfig,
+                       memoryTranslatorPortConfig : Any = null,
+                       injectorStage : Boolean = false,
+                       withoutInjectorStage : Boolean = false,
+                       relaxPredictorAddress : Boolean = true,
+                       predictionBuffer : Boolean = true)  extends IBusFetcherImpl(
+  resetVector = resetVector,
+  keepPcPlus4 = keepPcPlus4,
+  decodePcGen = compressedGen,
+  compressedGen = compressedGen,
+  cmdToRspStageCount = (if(config.twoCycleCache) 2 else 1) + (if(relaxedPcCalculation) 1 else 0),
+  allowPcRegReusedForSecondStage = true,
+  injectorReadyCutGen = false,
+  prediction = prediction,
+  historyRamSizeLog2 = historyRamSizeLog2,
+  injectorStage = (!config.twoCycleCache && !withoutInjectorStage) || injectorStage,
+  relaxPredictorAddress = relaxPredictorAddress,
+  fetchRedoGen = true,
+  predictionBuffer = predictionBuffer) with VexRiscvRegressionArg{
+  import config._
+
+
+
+  assert(isPow2(cacheSize))
+  assert(!(memoryTranslatorPortConfig != null && config.cacheSize/config.wayCount > 4096), "When the I$ is used with MMU, each way can't be bigger than a page (4096 bytes)")
+
+
+  assert(!(withoutInjectorStage && injectorStage))
+
+
+  override def getVexRiscvRegressionArgs(): Seq[String] = {
+    var args = List[String]()
+    args :+= "IBUS=CACHED"
+    args :+= s"IBUS_DATA_WIDTH=$memDataWidth"
+    args :+= s"COMPRESSED=${if(compressedGen) "yes" else "no"}"
+    args
+  }
+
+  var iBus  : InstructionCacheMemBus = null
+  var mmuBus : MemoryTranslatorBus = null
+  var privilegeService : PrivilegeService = null
+  var decodeExceptionPort : Flow[ExceptionCause] = null
+  val tightlyCoupledPorts = ArrayBuffer[TightlyCoupledPort]()
+  def tightlyGen = tightlyCoupledPorts.nonEmpty
+
+  def newTightlyCoupledPort(p : TightlyCoupledPortParameter) = {
+    val port = TightlyCoupledPort(p, null)
+    tightlyCoupledPorts += port
+    this
+  }
+
+
+  object FLUSH_ALL extends Stageable(Bool)
+  object IBUS_ACCESS_ERROR extends Stageable(Bool)
+  object IBUS_MMU_MISS extends Stageable(Bool)
+  object IBUS_ILLEGAL_ACCESS extends Stageable(Bool)
+  override def setup(pipeline: VexRiscv): Unit = {
+    import Riscv._
+    import pipeline.config._
+
+    super.setup(pipeline)
+
+    val decoderService = pipeline.service(classOf[DecoderService])
+    decoderService.addDefault(FLUSH_ALL, False)
+    decoderService.add(FENCE_I,  List(
+        FLUSH_ALL -> True
+    ))
+
+    if(catchSomething) {
+      val exceptionService = pipeline.service(classOf[ExceptionService])
+      decodeExceptionPort = exceptionService.newExceptionPort(pipeline.decode,1)
+    }
+
+    if(pipeline.serviceExist(classOf[MemoryTranslator]))
+      mmuBus = pipeline.service(classOf[MemoryTranslator]).newTranslationPort(MemoryTranslatorPort.PRIORITY_INSTRUCTION, memoryTranslatorPortConfig)
+
+    privilegeService = pipeline.serviceElse(classOf[PrivilegeService], PrivilegeServiceDefault())
+
+    if(pipeline.serviceExist(classOf[ReportService])){
+      val report = pipeline.service(classOf[ReportService])
+      report.add("iBus" -> {
+        val e = new BusReport()
+        val c = new CacheReport()
+        e.kind = "cached"
+        e.flushInstructions.add(0x100F) //FENCE.I
+        e.flushInstructions.add(0x13)
+        e.flushInstructions.add(0x13)
+        e.flushInstructions.add(0x13)
+
+        e.info = c
+        c.size = cacheSize
+        c.bytePerLine = bytePerLine
+
+        e
+      })
+    }
+  }
+
+
+  override def build(pipeline: VexRiscv): Unit = {
+    import pipeline._
+    import pipeline.config._
+
+    pipeline plug new FetchArea(pipeline) {
+      val cache = new InstructionCache(IBusCachedPlugin.this.config.copy(bypassGen = tightlyGen), if(mmuBus != null) mmuBus.p else MemoryTranslatorBusParameter(0,0))
+      iBus = master(new InstructionCacheMemBus(IBusCachedPlugin.this.config)).setName("iBus")
+      iBus <> cache.io.mem
+      iBus.cmd.address.allowOverride := cache.io.mem.cmd.address
+
+      //Memory bandwidth counter
+      val rspCounter = Reg(UInt(32 bits)) init(0)
+      when(iBus.rsp.valid){
+        rspCounter := rspCounter + 1
+      }
+
+      val stageOffset = if(relaxedPcCalculation) 1 else 0
+      def stages = iBusRsp.stages.drop(stageOffset)
+
+      tightlyCoupledPorts.foreach(p => p.bus = master(TightlyCoupledBus()).setName(p.p.name))
+
+      val s0 = new Area {
+        //address decoding
+        val tightlyCoupledHits = Vec(tightlyCoupledPorts.map(_.p.hit(stages(0).input.payload)))
+        val tightlyCoupledHit = tightlyCoupledHits.orR
+
+        for((port, hit) <- (tightlyCoupledPorts, tightlyCoupledHits).zipped){
+          port.bus.enable := stages(0).input.fire && hit
+          port.bus.address := stages(0).input.payload(31 downto 2) @@ U"00"
+        }
+
+        //Connect prefetch cache side
+        cache.io.cpu.prefetch.isValid := stages(0).input.valid && !tightlyCoupledHit
+        cache.io.cpu.prefetch.pc := stages(0).input.payload
+        stages(0).halt setWhen (cache.io.cpu.prefetch.haltIt)
+
+        if(mmuBus != null && mmuBus.p.latency == 1) {
+          stages(0).halt setWhen(mmuBus.busy)
+          mmuBus.cmd(0).isValid := cache.io.cpu.prefetch.isValid
+          mmuBus.cmd(0).isStuck := !stages(0).input.ready
+          mmuBus.cmd(0).virtualAddress := cache.io.cpu.prefetch.pc
+          mmuBus.cmd(0).bypassTranslation := False
+        }
+      }
+
+
+      val s1 = new Area {
+        val tightlyCoupledHits = RegNextWhen(s0.tightlyCoupledHits, stages(1).input.ready)
+        val tightlyCoupledHit = RegNextWhen(s0.tightlyCoupledHit, stages(1).input.ready)
+
+        if(tightlyGen) cache.io.cpu.fetch.dataBypassValid := tightlyCoupledHit
+        if(tightlyGen) cache.io.cpu.fetch.dataBypass := MuxOH(tightlyCoupledHits, tightlyCoupledPorts.map(e => CombInit(e.bus.data)))
+
+        //Connect fetch cache side
+        cache.io.cpu.fetch.isValid := stages(1).input.valid && !tightlyCoupledHit
+        cache.io.cpu.fetch.isStuck := !stages(1).input.ready
+        cache.io.cpu.fetch.pc := stages(1).input.payload
+
+        if(mmuBus != null) {
+          mmuBus.cmd.last.isValid := cache.io.cpu.fetch.isValid
+          mmuBus.cmd.last.isStuck := !stages(1).input.ready
+          mmuBus.cmd.last.virtualAddress := cache.io.cpu.fetch.pc
+          mmuBus.cmd.last.bypassTranslation := False
+          mmuBus.end := stages(1).input.ready || externalFlush
+          if (mmuBus.p.latency == 0) stages(1).halt setWhen (mmuBus.busy)
+        }
+
+
+        if (!twoCycleCache) {
+          cache.io.cpu.fetch.isUser := privilegeService.isUser()
+        }
+      }
+
+      val s2 = twoCycleCache generate new Area {
+        val tightlyCoupledHit = RegNextWhen(s1.tightlyCoupledHit, stages(2).input.ready)
+        cache.io.cpu.decode.isValid := stages(2).input.valid && !tightlyCoupledHit
+        cache.io.cpu.decode.isStuck := !stages(2).input.ready
+        cache.io.cpu.decode.pc := stages(2).input.payload
+        cache.io.cpu.decode.isUser := privilegeService.isUser()
+
+        if ((!twoCycleRam || wayCount == 1) && !compressedGen && !injectorStage) {
+          decode.insert(INSTRUCTION_ANTICIPATED) := Mux(decode.arbitration.isStuck, decode.input(INSTRUCTION), cache.io.cpu.fetch.data)
+        }
+      }
+
+      val rsp = new Area {
+        val iBusRspOutputHalt = False
+
+        val cacheRsp = if (twoCycleCache) cache.io.cpu.decode else cache.io.cpu.fetch
+        val cacheRspArbitration = stages(if (twoCycleCache) 2 else 1)
+        var issueDetected = False
+        val redoFetch = False
+
+
+        //Refill / redo
+        assert(decodePcGen == compressedGen)
+        cache.io.cpu.fill.valid := redoFetch && !cacheRsp.mmuRefilling
+        cache.io.cpu.fill.payload := cacheRsp.physicalAddress
+
+
+        if (catchSomething) {
+          decodeExceptionPort.valid := False
+          decodeExceptionPort.code.assignDontCare()
+          decodeExceptionPort.badAddr := cacheRsp.pc(31 downto 2) @@ U"00"
+        }
+
+        when(cacheRsp.isValid && cacheRsp.mmuRefilling && !issueDetected) {
+          issueDetected \= True
+          redoFetch := True
+        }
+
+        if(catchIllegalAccess) when(cacheRsp.isValid && cacheRsp.mmuException && !issueDetected) {
+          issueDetected \= True
+          decodeExceptionPort.valid := iBusRsp.readyForError
+          decodeExceptionPort.code := 12
+        }
+
+        when(cacheRsp.isValid && cacheRsp.cacheMiss && !issueDetected) {
+          issueDetected \= True
+          cache.io.cpu.fill.valid := True
+          redoFetch := True
+        }
+
+        if(catchAccessFault) when(cacheRsp.isValid && cacheRsp.error && !issueDetected) {
+          issueDetected \= True
+          decodeExceptionPort.valid := iBusRsp.readyForError
+          decodeExceptionPort.code := 1
+        }
+
+        when(redoFetch) {
+          iBusRsp.redoFetch := True
+        }
+
+
+        cacheRspArbitration.halt setWhen (issueDetected || iBusRspOutputHalt)
+        iBusRsp.output.valid := cacheRspArbitration.output.valid
+        cacheRspArbitration.output.ready := iBusRsp.output.ready
+        iBusRsp.output.rsp.inst := cacheRsp.data
+        iBusRsp.output.pc := cacheRspArbitration.output.payload
+      }
+
+      if (mmuBus != null) {
+        cache.io.cpu.fetch.mmuRsp <> mmuBus.rsp
+      } else {
+        cache.io.cpu.fetch.mmuRsp.physicalAddress := cache.io.cpu.fetch.pc
+        cache.io.cpu.fetch.mmuRsp.allowExecute := True
+        cache.io.cpu.fetch.mmuRsp.allowRead := True
+        cache.io.cpu.fetch.mmuRsp.allowWrite := True
+        cache.io.cpu.fetch.mmuRsp.isIoAccess := False
+        cache.io.cpu.fetch.mmuRsp.exception := False
+        cache.io.cpu.fetch.mmuRsp.refilling := False
+      }
+
+      val flushStage = decode
+      cache.io.flush := flushStage.arbitration.isValid && flushStage.input(FLUSH_ALL)
+    }
+  }
+}