From a7ae7e5758eea704ed284667df0295e9b304a30c Mon Sep 17 00:00:00 2001
From: Henry Cook <hcook@s144.Millennium.Berkeley.EDU>
Date: Thu, 28 Feb 2013 19:49:05 -0800
Subject: [PATCH] Cleaned up self-probes

---
 uncore/src/coherence.scala |  7 +++++++
 uncore/src/uncore.scala    | 11 +++--------
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/uncore/src/coherence.scala b/uncore/src/coherence.scala
index effba2e9..f7a75afc 100644
--- a/uncore/src/coherence.scala
+++ b/uncore/src/coherence.scala
@@ -49,6 +49,7 @@ abstract class CoherencePolicy {
   def needsMemRead(a_type: UFix, global_state: UFix): Bool
   def needsMemWrite(a_type: UFix, global_state: UFix): Bool
   def needsAckReply(a_type: UFix, global_state: UFix): Bool
+  def needsSelfProbe(acq: Acquire): Bool
   def requiresAck(grant: Grant): Bool
   def requiresAck(release: Release): Bool
   def pendingVoluntaryReleaseIsSufficient(r_type: UFix, p_type: UFix): Bool
@@ -79,6 +80,7 @@ abstract class IncoherentPolicy extends CoherencePolicy {
   def needsMemRead(a_type: UFix, global_state: UFix): Bool = Bool(false)
   def needsMemWrite(a_type: UFix, global_state: UFix): Bool = Bool(false)
   def needsAckReply(a_type: UFix, global_state: UFix): Bool = Bool(false)
+  def needsSelfProbe(acq: Acquire) = Bool(false)
   def requiresAck(grant: Grant) = Bool(true)
   def requiresAck(release: Release) = Bool(false)
   def pendingVoluntaryReleaseIsSufficient(r_type: UFix, p_type: UFix): Bool = Bool(false)
@@ -268,6 +270,7 @@ class MICoherence extends CoherencePolicyWithUncached {
   }
   def requiresAck(grant: Grant) = Bool(true)
   def requiresAck(release: Release) = Bool(false)
+  def needsSelfProbe(acq: Acquire) = acq.a_type === acquireReadUncached
   def pendingVoluntaryReleaseIsSufficient(r_type: UFix, p_type: UFix): Bool = (r_type === releaseVoluntaryInvalidateData)
 }
 
@@ -421,6 +424,7 @@ class MEICoherence extends CoherencePolicyWithUncached {
   }
   def requiresAck(grant: Grant) = Bool(true)
   def requiresAck(release: Release) = Bool(false)
+  def needsSelfProbe(acq: Acquire) = acq.a_type === acquireReadUncached
 
   def pendingVoluntaryReleaseIsSufficient(r_type: UFix, p_type: UFix): Bool = (r_type === releaseVoluntaryInvalidateData)
 }
@@ -578,6 +582,7 @@ class MSICoherence extends CoherencePolicyWithUncached {
   }
   def requiresAck(grant: Grant) = Bool(true)
   def requiresAck(release: Release) = Bool(false)
+  def needsSelfProbe(acq: Acquire) = acq.a_type === acquireReadUncached
 
   def pendingVoluntaryReleaseIsSufficient(r_type: UFix, p_type: UFix): Bool = (r_type === releaseVoluntaryInvalidateData)
 }
@@ -740,6 +745,7 @@ class MESICoherence extends CoherencePolicyWithUncached {
 
   def requiresAck(grant: Grant) = Bool(true)
   def requiresAck(release: Release) = Bool(false)
+  def needsSelfProbe(acq: Acquire) = acq.a_type === acquireReadUncached
 
   def pendingVoluntaryReleaseIsSufficient(r_type: UFix, p_type: UFix): Bool = (r_type === releaseVoluntaryInvalidateData)
 }
@@ -918,6 +924,7 @@ class MigratoryCoherence extends CoherencePolicyWithUncached {
   }
   def requiresAck(grant: Grant) = Bool(true)
   def requiresAck(release: Release) = Bool(false)
+  def needsSelfProbe(acq: Acquire) = acq.a_type === acquireReadUncached
 
   def pendingVoluntaryReleaseIsSufficient(r_type: UFix, p_type: UFix): Bool = (r_type === releaseVoluntaryInvalidateData)
 }
diff --git a/uncore/src/uncore.scala b/uncore/src/uncore.scala
index 8d1d396d..e3ebbc07 100644
--- a/uncore/src/uncore.scala
+++ b/uncore/src/uncore.scala
@@ -105,14 +105,9 @@ class XactTrackerBroadcast(id: Int)(implicit conf: CoherenceHubConfiguration) ex
   val probe_initial_flags = Bits(width = conf.ln.nTiles)
   probe_initial_flags := Bits(0)
   if (conf.ln.nTiles > 1) {
-    // issue self-probes for uncached read xacts to facilitate I$ coherence
-    // TODO: this is hackish; figure out how to do it more systematically
-    val probe_self = co match {
-      case u: CoherencePolicyWithUncached => u.isUncachedReadTransaction(io.alloc_req.bits.acquire)
-      case _ => Bool(false)
-    }
-    val myflag = Mux(probe_self, Bits(0), UFixToOH(io.alloc_req.bits.client_id(log2Up(conf.ln.nTiles)-1,0)))
-    probe_initial_flags := ~(io.tile_incoherent | myflag)
+    val probe_self = co.needsSelfProbe(io.alloc_req.bits.acquire) 
+    val probe_self_flag = Mux(probe_self, Bits(0), UFixToOH(io.alloc_req.bits.client_id(log2Up(conf.ln.nTiles)-1,0)))
+    probe_initial_flags := ~(io.tile_incoherent | probe_self_flag)
   }
 
   io.busy := state != s_idle