From 1ed89f1cab183956507885c2ce8be27b1904265e Mon Sep 17 00:00:00 2001
From: Henry Cook <hcook@s144.Millennium.Berkeley.EDU>
Date: Tue, 24 Apr 2012 15:11:59 -0700
Subject: [PATCH] Fixed abort bug: removed uneeded state, added mshr guard on
 xact_abort.valid and xact_init.ready on same cycle

---
 rocket/src/main/scala/nbdcache.scala |  1 +
 rocket/src/main/scala/uncore.scala   | 12 +++++-------
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/rocket/src/main/scala/nbdcache.scala b/rocket/src/main/scala/nbdcache.scala
index 3ce359a1..55e0acd1 100644
--- a/rocket/src/main/scala/nbdcache.scala
+++ b/rocket/src/main/scala/nbdcache.scala
@@ -226,6 +226,7 @@ class MSHR(id: Int, co: CoherencePolicy) extends Component {
   }
   when (state === s_refill_req) {
     when (flush) { state := s_drain_rpq }
+    .elsewhen (abort) { state := s_refill_req }
     .elsewhen (io.mem_req.ready) { state := s_refill_resp }
   }
   when (state === s_meta_clear && io.meta_req.ready) {
diff --git a/rocket/src/main/scala/uncore.scala b/rocket/src/main/scala/uncore.scala
index 29d0befd..0f482113 100644
--- a/rocket/src/main/scala/uncore.scala
+++ b/rocket/src/main/scala/uncore.scala
@@ -408,7 +408,7 @@ class CoherenceHubBroadcast(ntiles: Int, co: CoherencePolicy) extends CoherenceH
   }
 
   // Nack conflicting transaction init attempts
-  val s_idle :: s_abort_drain :: s_abort_send :: s_abort_complete :: Nil = Enum(4){ UFix() }
+  val s_idle :: s_abort_drain :: s_abort_send :: Nil = Enum(3){ UFix() }
   val abort_state_arr = Vec(ntiles) { Reg(resetVal = s_idle) }
   val want_to_abort_arr = Vec(ntiles) { Wire() { Bool()} }
   for( j <- 0 until ntiles ) {
@@ -445,13 +445,10 @@ class CoherenceHubBroadcast(ntiles: Int, co: CoherencePolicy) extends CoherenceH
       }
       is(s_abort_send) { // nothing is dequeued for now
         x_abort.valid := Bool(true)
-        when(x_abort.ready) {
-          abort_state_arr(j) := s_abort_complete
+        when(x_abort.ready) { // raises x_init.ready below
+          abort_state_arr(j) := s_idle
         }
       }
-      is(s_abort_complete) { // raises x_init.ready below
-        abort_state_arr(j) := s_idle 
-      }
     }
   }
   
@@ -475,6 +472,7 @@ class CoherenceHubBroadcast(ntiles: Int, co: CoherencePolicy) extends CoherenceH
     val x_init = io.tiles(j).xact_init
     val x_init_data = io.tiles(j).xact_init_data
     val x_init_data_dep = x_init_data_dep_list(j).io.deq
+    val x_abort = io.tiles(j).xact_abort
     init_arb.io.in(j).valid := (abort_state_arr(j) === s_idle) && !want_to_abort_arr(j) && x_init.valid
     init_arb.io.in(j).bits.xact_init := x_init.bits
     init_arb.io.in(j).bits.tile_id := UFix(j)
@@ -482,7 +480,7 @@ class CoherenceHubBroadcast(ntiles: Int, co: CoherencePolicy) extends CoherenceH
     val do_pop = foldR(pop_x_inits)(_||_)
     x_init_data_dep_list(j).io.enq.valid := do_pop && co.messageHasData(x_init.bits) && (abort_state_arr(j) === s_idle) 
     x_init_data_dep_list(j).io.enq.bits.global_xact_id := OHToUFix(pop_x_inits)
-    x_init.ready := (abort_state_arr(j) === s_abort_complete) || do_pop
+    x_init.ready := (x_abort.valid && x_abort.ready) || do_pop
     x_init_data.ready := (abort_state_arr(j) === s_abort_drain) || foldR(trackerList.map(_.io.pop_x_init_data(j).toBool))(_||_)
     x_init_data_dep.ready := foldR(trackerList.map(_.io.pop_x_init_dep(j).toBool))(_||_)
   }