From 9a3b2e7006c370b6c37bee57272a0d1788d50e5b Mon Sep 17 00:00:00 2001
From: Henry Cook <hcook@s144.Millennium.Berkeley.EDU>
Date: Wed, 1 May 2013 16:48:01 -0700
Subject: [PATCH] new paired meta/data IO type, and matching arbiter

---
 uncore/src/package.scala | 62 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/uncore/src/package.scala b/uncore/src/package.scala
index 7e1fc7a0..46c39d51 100644
--- a/uncore/src/package.scala
+++ b/uncore/src/package.scala
@@ -8,6 +8,68 @@ import scala.collection.mutable.Stack
 
 implicit def toOption[A](a: A) = Option(a)
 
+class PairedDataIO[M <: Data, D <: Data]()(m: => M, d: => D) extends Bundle {
+  val meta = (new FIFOIO()){ m }
+  val data = (new FIFOIO()){ d }
+}
+
+class PairedArbiterIO[M <: Data, D <: Data](n: Int)(m: => M, d: => D) extends Bundle {
+  val in  = Vec(n) { new PairedDataIO()(m,d) }.flip
+  val out = new PairedDataIO()(m,d)  
+  val meta_chosen = Bits(OUTPUT, log2Up(n)) 
+  val data_chosen = Bits(OUTPUT, log2Up(n)) 
+}
+
+class PairedLockingRRArbiter[M <: Data, D <: Data](n: Int, count: Int, needsLock: Option[M => Bool] = None)(meta: => M, data: => D) {
+  require(isPow2(count))
+  val io = new PairedArbiterIO(n)(meta,data)
+  val locked  = if(count > 1) Reg(resetVal = Bool(false)) else Bool(false)
+  val lockIdx = if(count > 1) Reg(resetVal = UFix(n-1)) else UFix(n-1)
+  val grant = List.fill(n)(Bool())
+  val meta_chosen = Bits(width = log2Up(n))
+
+  val chosen_meta_has_data = io.out.meta.valid && needsLock.map(_(io.out.meta.bits)).getOrElse(Bool(true))
+  (0 until n).map(i => io.in(i).meta.ready := grant(i) && io.out.meta.ready)
+  (0 until n).map(i => io.in(i).data.ready := Mux(locked, lockIdx === UFix(i), grant(i) && chosen_meta_has_data) && io.out.data.ready)
+  io.out.meta.valid := io.in(meta_chosen).meta.valid
+  io.out.data.valid := Mux(locked, io.in(lockIdx).data.valid, io.in(meta_chosen).data.valid && chosen_meta_has_data)
+  io.out.meta.bits := io.in(meta_chosen).meta.bits
+  io.out.data.bits := Mux(locked, io.in(lockIdx).data.bits, io.in(meta_chosen).data.bits)
+  io.meta_chosen := meta_chosen
+  io.data_chosen := Mux(locked, lockIdx, meta_chosen)
+
+  if(count > 1){
+    val cnt = Reg(resetVal = UFix(0, width = log2Up(count)))
+    val cnt_next = cnt + UFix(1)
+    when(io.out.data.fire()){
+      cnt := cnt_next
+      when(cnt_next === UFix(0)) {
+        locked := Bool(false)
+      }
+    }
+    when(io.out.meta.fire()) {
+      when(needsLock.map(_(io.out.meta.bits)).getOrElse(Bool(true))) {
+        when(!locked) {
+          locked := Bool(true)
+          lockIdx := Vec(io.in.map{in => in.meta.fire()}){Bool()}.indexWhere{i: Bool => i} 
+        }
+      }
+    }
+  }
+  val last_grant = Reg(resetVal = Bits(0, log2Up(n)))
+  val ctrl = ArbiterCtrl((0 until n).map(i => io.in(i).meta.valid && UFix(i) > last_grant) ++ io.in.map(_.meta.valid))
+  (0 until n).map(i => grant(i) := ctrl(i) && UFix(i) > last_grant || ctrl(i + n))
+
+  var choose = Bits(n-1)
+  for (i <- n-2 to 0 by -1)
+    choose = Mux(io.in(i).meta.valid, Bits(i), choose)
+  for (i <- n-1 to 1 by -1)
+    choose = Mux(io.in(i).meta.valid && UFix(i) > last_grant, Bits(i), choose)
+  meta_chosen := choose
+
+  when (io.out.meta.fire()) { last_grant := meta_chosen }
+}
+
 case class PhysicalNetworkConfiguration(nEndpoints: Int, idBits: Int)
 
 class PhysicalHeader(implicit conf: PhysicalNetworkConfiguration) extends Bundle {