add support for AXI streaming protocol

junctions/src/main/scala/nasti.scala

@@ -113,14 +113,29 @@ class NastiReadDataChannel(implicit p: Parameters) extends NastiResponseChannel(
   val user = UInt(width = nastiRUserBits)
 }
 
+object NastiConstants {
+  val BURST_FIXED = UInt("b00")
+  val BURST_INCR  = UInt("b01")
+  val BURST_WRAP  = UInt("b10")
+
+  val RESP_OKAY = UInt("b00")
+  val RESP_EXOKAY = UInt("b01")
+  val RESP_SLVERR = UInt("b10")
+  val RESP_DECERR = UInt("b11")
+}
+
+import NastiConstants._
+
 object NastiWriteAddressChannel {
-  def apply(id: UInt, addr: UInt, size: UInt, len: UInt = UInt(0))(implicit p: Parameters) = {
+  def apply(id: UInt, addr: UInt, size: UInt,
+      len: UInt = UInt(0), burst: UInt = BURST_INCR)
+      (implicit p: Parameters) = {
     val aw = Wire(new NastiWriteAddressChannel)
     aw.id := id
     aw.addr := addr
     aw.len := len
     aw.size := size
-    aw.burst := UInt("b01")
+    aw.burst := burst
     aw.lock := Bool(false)
     aw.cache := UInt("b0000")
     aw.prot := UInt("b000")
@@ -132,13 +147,15 @@ object NastiWriteAddressChannel {
 }
 
 object NastiReadAddressChannel {
-  def apply(id: UInt, addr: UInt, size: UInt, len: UInt = UInt(0))(implicit p: Parameters) = {
+  def apply(id: UInt, addr: UInt, size: UInt,
+      len: UInt = UInt(0), burst: UInt = BURST_INCR)
+      (implicit p: Parameters) = {
     val ar = Wire(new NastiReadAddressChannel)
     ar.id := id
     ar.addr := addr
     ar.len := len
     ar.size := size
-    ar.burst := UInt("b01")
+    ar.burst := burst
     ar.lock := Bool(false)
     ar.cache := UInt(0)
     ar.prot := UInt(0)
@@ -333,7 +350,7 @@ class NastiErrorSlave(implicit p: Parameters) extends NastiModule {
   io.r.valid := r_queue.io.deq.valid && responding
   io.r.bits.id := r_queue.io.deq.bits.id
   io.r.bits.data := UInt(0)
-  io.r.bits.resp := Bits("b11")
+  io.r.bits.resp := RESP_DECERR
   io.r.bits.last := beats_left === UInt(0)
 
   r_queue.io.deq.ready := io.r.fire() && io.r.bits.last

junctions/src/main/scala/stream.scala

@@ -0,0 +1,79 @@
+package junctions
+
+import Chisel._
+import NastiConstants._
+import cde.Parameters
+
+class StreamChannel(w: Int) extends Bundle {
+  val data = UInt(width = w)
+  val last = Bool()
+
+  override def cloneType = new StreamChannel(w).asInstanceOf[this.type]
+}
+
+class StreamIO(w: Int) extends Bundle {
+  val out = Decoupled(new StreamChannel(w))
+  val in = Decoupled(new StreamChannel(w)).flip
+
+  override def cloneType = new StreamIO(w).asInstanceOf[this.type]
+}
+
+class NastiIOStreamIOConverter(w: Int)(implicit p: Parameters) extends Module {
+  val io = new Bundle {
+    val nasti = (new NastiIO).flip
+    val stream = new StreamIO(w)
+  }
+
+  val streamSize = UInt(log2Up(w / 8))
+  assert(!io.nasti.ar.valid || io.nasti.ar.bits.size === streamSize,
+         "read channel wrong size on stream")
+  assert(!io.nasti.ar.valid || io.nasti.ar.bits.burst === BURST_FIXED,
+         "read channel wrong burst type on stream")
+  assert(!io.nasti.aw.valid || io.nasti.aw.bits.size === streamSize,
+         "write channel wrong size on stream")
+  assert(!io.nasti.aw.valid || io.nasti.aw.bits.burst === BURST_FIXED,
+         "write channel wrong burst type on stream")
+
+  val read_id = Reg(io.nasti.ar.bits.id)
+  val reading = Reg(init = Bool(false))
+
+  io.nasti.ar.ready := !reading
+  io.nasti.r.valid := reading && io.stream.in.valid
+  io.nasti.r.bits := io.stream.in.bits
+  io.nasti.r.bits.resp := UInt(0)
+  io.nasti.r.bits.id := read_id
+  io.stream.in.ready := reading && io.nasti.r.ready
+
+  when (io.nasti.ar.fire()) {
+    read_id := io.nasti.ar.bits.id
+    reading := Bool(true)
+  }
+
+  when (io.nasti.r.fire() && io.nasti.r.bits.last) {
+    reading := Bool(false)
+  }
+
+  val write_id = Reg(io.nasti.aw.bits.id)
+  val writing = Reg(init = Bool(false))
+  val write_resp = Reg(init = Bool(false))
+
+  io.nasti.aw.ready := !writing && !write_resp
+  io.nasti.w.ready := writing && io.stream.out.ready
+  io.stream.out.valid := writing && io.nasti.w.valid
+  io.stream.out.bits := io.nasti.w.bits
+  io.nasti.b.valid := write_resp
+  io.nasti.b.bits.resp := UInt(0)
+  io.nasti.b.bits.id := write_id
+
+  when (io.nasti.aw.fire()) {
+    write_id := io.nasti.aw.bits.id
+    writing := Bool(true)
+  }
+
+  when (io.nasti.w.fire() && io.nasti.w.bits.last) {
+    writing := Bool(false)
+    write_resp := Bool(true)
+  }
+
+  when (io.nasti.b.fire()) { write_resp := Bool(false) }
+}