1 files changed, 357 insertions, 0 deletions
diff --git a/VexRiscv/src/main/scala/vexriscv/plugin/CfuPlugin.scala b/VexRiscv/src/main/scala/vexriscv/plugin/CfuPlugin.scala
new file mode 100644
index 0000000..d343640
--- /dev/null
+++ b/VexRiscv/src/main/scala/vexriscv/plugin/CfuPlugin.scala
@@ -0,0 +1,357 @@
+package vexriscv.plugin
+
+import vexriscv.{DecoderService, ExceptionCause, ExceptionService, Stage, Stageable, VexRiscv}
+import spinal.core._
+import spinal.lib._
+import spinal.lib.bus.bmb.WeakConnector
+import spinal.lib.bus.misc.{AddressMapping, DefaultMapping}
+import vexriscv.Riscv.IMM
+
+case class CfuPluginParameter(
+                        CFU_VERSION : Int,
+                        CFU_INTERFACE_ID_W : Int,
+                        CFU_FUNCTION_ID_W : Int,
+                        CFU_REORDER_ID_W : Int,
+                        CFU_REQ_RESP_ID_W : Int,
+                        CFU_INPUTS : Int,
+                        CFU_INPUT_DATA_W : Int,
+                        CFU_OUTPUTS : Int,
+                        CFU_OUTPUT_DATA_W : Int,
+                        CFU_FLOW_REQ_READY_ALWAYS : Boolean,
+                        CFU_FLOW_RESP_READY_ALWAYS : Boolean)
+
+case class CfuBusParameter(CFU_VERSION : Int = 0,
+                           CFU_INTERFACE_ID_W : Int = 0,
+                           CFU_FUNCTION_ID_W : Int,
+                           CFU_CFU_ID_W : Int = 0,
+                           CFU_REORDER_ID_W : Int = 0,
+                           CFU_REQ_RESP_ID_W : Int = 0,
+                           CFU_STATE_INDEX_NUM : Int = 0,
+                           CFU_INPUTS : Int,
+                           CFU_INPUT_DATA_W : Int,
+                           CFU_OUTPUTS : Int,
+                           CFU_OUTPUT_DATA_W : Int,
+                           CFU_FLOW_REQ_READY_ALWAYS : Boolean,
+                           CFU_FLOW_RESP_READY_ALWAYS : Boolean,
+                           CFU_WITH_STATUS : Boolean = false,
+                           CFU_RAW_INSN_W : Int = 0)
+
+case class CfuCmd( p : CfuBusParameter ) extends Bundle{
+  val function_id = UInt(p.CFU_FUNCTION_ID_W bits)
+  val reorder_id = UInt(p.CFU_REORDER_ID_W bits)
+  val request_id = UInt(p.CFU_REQ_RESP_ID_W bits)
+  val inputs = Vec(Bits(p.CFU_INPUT_DATA_W bits), p.CFU_INPUTS)
+  val state_index = UInt(log2Up(p.CFU_STATE_INDEX_NUM) bits)
+  val cfu_index = UInt(p.CFU_CFU_ID_W bits)
+  val raw_insn = Bits(p.CFU_RAW_INSN_W bits)
+  def weakAssignFrom(m : CfuCmd): Unit ={
+    def s = this
+    WeakConnector(m, s, m.function_id, s.function_id, defaultValue = null, allowUpSize = false, allowDownSize = true , allowDrop = true)
+    WeakConnector(m, s, m.reorder_id,  s.reorder_id,  defaultValue = null, allowUpSize = false , allowDownSize = false, allowDrop = false)
+    WeakConnector(m, s, m.request_id,  s.request_id,  defaultValue = null, allowUpSize = false, allowDownSize = false, allowDrop = false)
+    s.inputs := m.inputs
+  }
+}
+
+case class CfuRsp(p : CfuBusParameter) extends Bundle{
+  val response_id = UInt(p.CFU_REQ_RESP_ID_W bits)
+  val outputs = Vec(Bits(p.CFU_OUTPUT_DATA_W bits), p.CFU_OUTPUTS)
+  val status = p.CFU_WITH_STATUS generate Bits(3 bits)
+
+  def weakAssignFrom(m : CfuRsp): Unit ={
+    def s = this
+    s.response_id := m.response_id
+    s.outputs := m.outputs
+  }
+}
+
+case class CfuBus(p : CfuBusParameter) extends Bundle with IMasterSlave{
+  val cmd = Stream(CfuCmd(p))
+  val rsp = Stream(CfuRsp(p))
+
+  def <<(m : CfuBus) : Unit = {
+    val s = this
+    s.cmd.arbitrationFrom(m.cmd)
+    m.rsp.arbitrationFrom(s.rsp)
+
+    s.cmd.weakAssignFrom(m.cmd)
+    m.rsp.weakAssignFrom(s.rsp)
+  }
+
+  override def asMaster(): Unit = {
+    master(cmd)
+    slave(rsp)
+  }
+}
+
+object CfuPlugin{
+  object Input2Kind extends SpinalEnum{
+    val RS, IMM_I = newElement()
+  }
+}
+
+case class CfuPluginEncoding(instruction : MaskedLiteral,
+                             functionId : List[Range],
+                             input2Kind : CfuPlugin.Input2Kind.E){
+  val functionIdWidth = functionId.map(_.size).sum
+}
+
+class CfuPlugin(val stageCount : Int,
+                val allowZeroLatency : Boolean,
+                val busParameter : CfuBusParameter,
+                val encodings : List[CfuPluginEncoding] = null,
+                val stateAndIndexCsrOffset : Int = 0xBC0,
+                val statusCsrOffset : Int = 0x801,
+                val withEnable : Boolean = true) extends Plugin[VexRiscv]{
+  def p = busParameter
+
+  assert(p.CFU_INPUTS <= 2)
+  assert(p.CFU_OUTPUTS == 1)
+//  assert(p.CFU_FUNCTION_ID_W == 3)
+
+  var bus : CfuBus = null
+
+  lazy val forkStage = pipeline.execute
+  lazy val joinStage = pipeline.stages(Math.min(pipeline.stages.length - 1, pipeline.indexOf(forkStage) + stageCount))
+
+
+  val CFU_ENABLE = new Stageable(Bool()).setCompositeName(this, "CFU_ENABLE")
+  val CFU_IN_FLIGHT = new Stageable(Bool()).setCompositeName(this, "CFU_IN_FLIGHT")
+  val CFU_ENCODING = new Stageable(UInt(log2Up(encodings.size) bits)).setCompositeName(this, "CFU_ENCODING")
+  val CFU_INPUT_2_KIND = new Stageable(CfuPlugin.Input2Kind()).setCompositeName(this, "CFU_INPUT_2_KIND")
+
+  override def setup(pipeline: VexRiscv): Unit = {
+    import pipeline._
+    import pipeline.config._
+
+    bus = master(CfuBus(p))
+
+    val decoderService = pipeline.service(classOf[DecoderService])
+    decoderService.addDefault(CFU_ENABLE, False)
+
+    for((encoding, id) <- encodings.zipWithIndex){
+      var actions = List(
+        CFU_ENABLE -> True,
+        REGFILE_WRITE_VALID      -> True,
+        BYPASSABLE_EXECUTE_STAGE -> Bool(stageCount == 0),
+        BYPASSABLE_MEMORY_STAGE  -> Bool(stageCount <= 1),
+        RS1_USE -> True,
+        CFU_ENCODING -> U(id),
+        CFU_INPUT_2_KIND -> encoding.input2Kind()
+      )
+
+      encoding.input2Kind match {
+        case CfuPlugin.Input2Kind.RS =>
+          actions :+= RS2_USE -> True
+        case CfuPlugin.Input2Kind.IMM_I =>
+      }
+
+      decoderService.add(
+        key = encoding.instruction,
+        values = actions
+      )
+    }
+  }
+
+  override def build(pipeline: VexRiscv): Unit = {
+    import pipeline._
+    import pipeline.config._
+
+    val csr = pipeline plug new Area{
+      val factory = pipeline.service(classOf[CsrInterface])
+      val en = withEnable generate (Reg(Bool()) init(False))
+      if(withEnable) factory.rw(stateAndIndexCsrOffset, 31, en)
+
+      val stateId = Reg(UInt(log2Up(p.CFU_STATE_INDEX_NUM) bits)) init(0)
+      if(p.CFU_STATE_INDEX_NUM > 1) {
+        assert(stateAndIndexCsrOffset != -1, "CfuPlugin stateCsrIndex need to be set in the parameters")
+        factory.rw(stateAndIndexCsrOffset, 16, stateId)
+      }
+
+      val cfuIndex = Reg(UInt(p.CFU_CFU_ID_W bits)) init(0)
+      if(p.CFU_CFU_ID_W != 0){
+        factory.rw(stateAndIndexCsrOffset, 0, cfuIndex)
+      }
+      val status = p.CFU_WITH_STATUS generate new Area{
+        val CU, OP, FI, OF, SI, CI = RegInit(False)
+        val flags = List(CU, OP, FI, OF, SI, CI).reverse
+        factory.rw(statusCsrOffset,  flags.zipWithIndex.map(_.swap) :_*)
+        factory.duringWrite(statusCsrOffset){
+          decode.arbitration.haltByOther := True //Handle CSRW to decode
+        }
+      }
+    }
+
+    if(withEnable) when(decode.input(CFU_ENABLE) && !csr.en){
+      pipeline.service(classOf[DecoderService]).forceIllegal()
+    }
+
+    forkStage plug new Area{
+      import forkStage._
+      val hazard = stages.dropWhile(_ != forkStage).tail.map(s => s.arbitration.isValid && s.input(HAS_SIDE_EFFECT)).orR
+      val scheduleWish = arbitration.isValid && input(CFU_ENABLE)
+      val schedule = scheduleWish && !hazard
+      arbitration.haltItself setWhen(scheduleWish && hazard)
+
+      val hold = RegInit(False) setWhen(schedule) clearWhen(bus.cmd.ready)
+      val fired = RegInit(False) setWhen(bus.cmd.fire) clearWhen(!arbitration.isStuck)
+      insert(CFU_IN_FLIGHT) := schedule || hold || fired
+
+      bus.cmd.valid := (schedule || hold) && !fired
+      arbitration.haltItself setWhen(bus.cmd.valid && !bus.cmd.ready)
+
+//      bus.cmd.function_id := U(input(INSTRUCTION)(14 downto 12)).resized
+      val functionIdFromInstructinoWidth = encodings.map(_.functionIdWidth).max
+      val functionsIds = encodings.map(e => U(Cat(e.functionId.map(r => input(INSTRUCTION)(r))), functionIdFromInstructinoWidth bits))
+      bus.cmd.cfu_index := csr.cfuIndex
+      bus.cmd.state_index := csr.stateId
+      bus.cmd.function_id := functionsIds.read(input(CFU_ENCODING))
+      bus.cmd.reorder_id := 0
+      bus.cmd.request_id := 0
+      bus.cmd.raw_insn   := input(INSTRUCTION).resized
+      if(p.CFU_INPUTS >= 1) bus.cmd.inputs(0) := input(RS1)
+      if(p.CFU_INPUTS >= 2)  bus.cmd.inputs(1) := input(CFU_INPUT_2_KIND).mux(
+        CfuPlugin.Input2Kind.RS -> input(RS2),
+        CfuPlugin.Input2Kind.IMM_I -> IMM(input(INSTRUCTION)).h_sext
+      )
+    }
+
+    joinStage plug new Area{
+      import joinStage._
+
+      //If the CFU interface can produce a result combinatorialy and the fork stage isn't the same than the join stage
+      //Then it is required to add a buffer on rsp to not propagate the fork stage ready := False in the CPU pipeline.
+      val rsp = if(p.CFU_FLOW_RESP_READY_ALWAYS){
+        bus.rsp.toFlow.toStream.queueLowLatency(
+          size = stageCount + 1,
+          latency = 0
+        )
+      } else if(forkStage != joinStage && allowZeroLatency) {
+        bus.rsp.s2mPipe()
+      } else {
+        bus.rsp.combStage()
+      }
+
+      rsp.ready := False
+      when(input(CFU_IN_FLIGHT)){
+        arbitration.haltItself setWhen(!rsp.valid)
+        rsp.ready := !arbitration.isStuckByOthers
+        output(REGFILE_WRITE_DATA) := rsp.outputs(0)
+        if(p.CFU_WITH_STATUS) when(arbitration.isFiring){
+          switch(rsp.status) {
+            for (i <- 1 to 6) is(i) {
+              csr.status.flags(i-1) := True
+            }
+          }
+        }
+      }
+    }
+
+    pipeline.stages.drop(1).foreach(s => s.output(CFU_IN_FLIGHT) clearWhen(s.arbitration.isStuck))
+    addPrePopTask(() => stages.dropWhile(_ != memory).reverse.dropWhile(_ != joinStage).foreach(s => s.input(CFU_IN_FLIGHT).init(False)))
+  }
+}
+
+
+object CfuTest{
+
+//  stageCount = 0,
+//  allowZeroLatency = true,
+  def getCfuParameter() = CfuBusParameter(
+    CFU_VERSION = 0,
+    CFU_INTERFACE_ID_W = 0,
+    CFU_FUNCTION_ID_W = 3,
+    CFU_REORDER_ID_W = 0,
+    CFU_REQ_RESP_ID_W = 0,
+    CFU_INPUTS = 2,
+    CFU_INPUT_DATA_W = 32,
+    CFU_OUTPUTS = 1,
+    CFU_OUTPUT_DATA_W = 32,
+    CFU_FLOW_REQ_READY_ALWAYS = false,
+    CFU_FLOW_RESP_READY_ALWAYS = false
+  )
+}
+case class CfuTest() extends Component{
+  val io = new Bundle {
+    val bus = slave(CfuBus(CfuTest.getCfuParameter()))
+  }
+  io.bus.rsp.arbitrationFrom(io.bus.cmd)
+  io.bus.rsp.response_id := io.bus.cmd.request_id
+  io.bus.rsp.outputs(0) := ~(io.bus.cmd.inputs(0) & io.bus.cmd.inputs(1))
+}
+
+
+case class CfuBb(p : CfuBusParameter) extends BlackBox{
+  val io = new Bundle {
+    val clk, reset = in Bool()
+    val bus = slave(CfuBus(p))
+  }
+
+  mapCurrentClockDomain(io.clk, io.reset)
+}
+
+//case class CfuGray(p : CfuBusParameter) extends BlackBox{
+//  val req_function_id = in Bits(p.CFU_FUNCTION_ID_W)
+//  val req_data = in Bits(p.CFU_REQ_INPUTS)
+//  val resp_data = in Bits(p.CFU_FUNCTION_ID_W)
+//  input `CFU_FUNCTION_ID req_function_id,
+//  input [CFU_REQ_INPUTS-1:0]`CFU_REQ_DATA req_data,
+//  output [CFU_RESP_OUTPUTS-1:0]`CFU_RESP_DATA resp_data
+//  io.bus.rsp.arbitrationFrom(io.bus.cmd)
+//  io.bus.rsp.response_ok := True
+//  io.bus.rsp.response_id := io.bus.cmd.request_id
+//  io.bus.rsp.outputs(0) := ~(io.bus.cmd.inputs(0) & io.bus.cmd.inputs(1))
+//}
+
+
+case class CfuDecoder(p : CfuBusParameter,
+                      mappings : Seq[AddressMapping],
+                      pendingMax : Int = 3) extends Component{
+  val io = new Bundle {
+    val input = slave(CfuBus(p))
+    val outputs = Vec(master(CfuBus(p)), mappings.size)
+  }
+  val hasDefault = mappings.contains(DefaultMapping)
+  val logic = if(hasDefault && mappings.size == 1){
+    io.outputs(0) << io.input
+  } else new Area {
+    val hits = Vec(Bool, mappings.size)
+    for (portId <- 0 until mappings.length) yield {
+      val slaveBus = io.outputs(portId)
+      val memorySpace = mappings(portId)
+      val hit = hits(portId)
+      hit := (memorySpace match {
+        case DefaultMapping => !hits.filterNot(_ == hit).orR
+        case _ => memorySpace.hit(io.input.cmd.function_id)
+      })
+      slaveBus.cmd.valid := io.input.cmd.valid && hit
+      slaveBus.cmd.payload := io.input.cmd.payload.resized
+    }
+    val noHit = if (!hasDefault) !hits.orR else False
+    io.input.cmd.ready := (hits, io.outputs).zipped.map(_ && _.cmd.ready).orR || noHit
+
+    val rspPendingCounter = Reg(UInt(log2Up(pendingMax + 1) bits)) init(0)
+    rspPendingCounter := rspPendingCounter + U(io.input.cmd.fire) - U(io.input.rsp.fire)
+    val rspHits = RegNextWhen(hits, io.input.cmd.fire)
+    val rspPending = rspPendingCounter =/= 0
+    val rspNoHitValid = if (!hasDefault) !rspHits.orR else False
+    val rspNoHit = !hasDefault generate new Area{
+      val doIt = RegInit(False) clearWhen(io.input.rsp.fire) setWhen(io.input.cmd.fire && noHit)
+      val response_id = RegNextWhen(io.input.cmd.request_id, io.input.cmd.fire)
+    }
+
+    io.input.rsp.valid := io.outputs.map(_.rsp.valid).orR || (rspPending && rspNoHitValid)
+    io.input.rsp.payload := io.outputs.map(_.rsp.payload).read(OHToUInt(rspHits))
+    if(!hasDefault) when(rspNoHit.doIt) {
+      io.input.rsp.valid := True
+      io.input.rsp.response_id := rspNoHit.response_id
+    }
+    for(output <- io.outputs) output.rsp.ready := io.input.rsp.ready
+
+    val cmdWait = (rspPending && (hits =/= rspHits || rspNoHitValid)) || rspPendingCounter === pendingMax
+    when(cmdWait) {
+      io.input.cmd.ready := False
+      io.outputs.foreach(_.cmd.valid := False)
+    }
+  }
+}