From 6951f5b8e6358104fc41ca0226628168dbbd33d7 Mon Sep 17 00:00:00 2001
From: Dolu1990 <charles.papon.90@gmail.com>
Date: Mon, 29 Jul 2019 14:17:51 +0200
Subject: [PATCH] CfuPlugin addition

---
 .../scala/vexriscv/plugin/CfuPlugin.scala     | 120 ++++++++++++++++++
 1 file changed, 120 insertions(+)
 create mode 100644 src/main/scala/vexriscv/plugin/CfuPlugin.scala

diff --git a/src/main/scala/vexriscv/plugin/CfuPlugin.scala b/src/main/scala/vexriscv/plugin/CfuPlugin.scala
new file mode 100644
index 0000000..968580d
--- /dev/null
+++ b/src/main/scala/vexriscv/plugin/CfuPlugin.scala
@@ -0,0 +1,120 @@
+package vexriscv.plugin
+
+import vexriscv.{DecoderService, Stageable, VexRiscv}
+import spinal.core._
+import spinal.lib._
+
+case class CfuParameter(latency : Int,
+                        dropWidth : Int,
+                        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 : Int,
+                        CFU_FLOW_RESP_READY_ALWAYS : Int)
+
+case class CfuCmd(p : CfuParameter) 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)
+}
+
+case class CfuRsp(p : CfuParameter) extends Bundle{
+  val response_ok = Bool()
+  val response_id = UInt(p.CFU_REQ_RESP_ID_W bits)
+  val outputs = Vec(Bits(p.CFU_OUTPUT_DATA_W bits), p.CFU_OUTPUTS)
+}
+
+case class CfuBus(p : CfuParameter) extends Bundle with IMasterSlave{
+  val interface_id = UInt(p.CFU_INTERFACE_ID_W bits)
+  val cmd = Stream(CfuCmd(p))
+  val rsp = Stream(CfuRsp(p))
+
+  override def asMaster(): Unit = {
+    out(interface_id)
+    master(cmd)
+    slave(rsp)
+  }
+}
+
+class CfuPlugin(val p: CfuParameter) extends Plugin[VexRiscv]{
+  assert(p.CFU_INPUTS <= 2)
+  assert(p.CFU_OUTPUTS == 1)
+  assert(p.CFU_FLOW_REQ_READY_ALWAYS == false)
+  assert(p.CFU_FLOW_RESP_READY_ALWAYS == false)
+
+  var bus : CfuBus = null
+
+  object CFU_ENABLE extends Stageable(Bool())
+  object CFU_FUNCTION extends Stageable(UInt(p.CFU_FUNCTION_ID_W bits))
+  object CFU_IN_FLIGHT extends Stageable(Bool())
+
+  override def setup(pipeline: VexRiscv): Unit = {
+    import pipeline.config._
+
+    bus = CfuBus(p)
+
+    val decoderService = pipeline.service(classOf[DecoderService])
+    decoderService.add(List(
+      M"000000-----------000-----0010011"  -> List(
+        CFU_ENABLE -> True,
+        CFU_FUNCTION -> U"00",
+        REGFILE_WRITE_VALID      -> ???,
+        BYPASSABLE_EXECUTE_STAGE -> ???,
+        BYPASSABLE_MEMORY_STAGE  -> ???,
+        RS1_USE -> ???,
+        RS2_USE -> ???
+      ),
+      M"000000-----------001-----0010011"  -> List(
+        CFU_ENABLE -> True,
+        CFU_FUNCTION -> U"01",
+        REGFILE_WRITE_VALID      -> ???,
+        BYPASSABLE_EXECUTE_STAGE -> ???,
+        BYPASSABLE_MEMORY_STAGE  -> ???,
+        RS1_USE -> ???,
+        RS2_USE -> ???
+      )
+    ))
+  }
+
+  override def build(pipeline: VexRiscv): Unit = {
+    import pipeline._
+    import pipeline.config._
+
+    val forkStage = execute
+    val joinStageId = Math.min(stages.length - 1, pipeline.indexOf(execute) + p.latency - 1)
+    val joinStage = stages(joinStageId)
+
+    forkStage plug new Area{
+      import forkStage._
+      val schedule = arbitration.isValid && input(CFU_ENABLE)
+      val hold = RegInit(False) setWhen(schedule) clearWhen(bus.cmd.ready)
+      val fired = RegInit(False) setWhen(bus.cmd.fire) clearWhen(!arbitration.isStuckByOthers)
+      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 := input(CFU_FUNCTION)
+      bus.cmd.reorder_id := 0
+      bus.cmd.request_id := 0
+      if(p.CFU_INPUTS >= 1) bus.cmd.inputs(0) := input(RS1)
+      if(p.CFU_INPUTS >= 2) bus.cmd.inputs(1) := input(RS2)
+    }
+
+    joinStage plug new Area{
+      import joinStage._
+      when(input(CFU_IN_FLIGHT)){
+        arbitration.haltItself setWhen(!bus.rsp.valid)
+        bus.rsp.ready := arbitration.isStuckByOthers
+        output(REGFILE_WRITE_DATA) := bus.rsp.outputs(0)
+      }
+    }
+  }
+}