ruby: improved support for functional accesses

This patch adds support to different entities in the ruby memory system
for more reliable functional read/write accesses. Only the simple network
has been augmented as of now. Later on Garnet will also support functional
accesses.
The patch adds functional access code to all the different types of messages
that protocols can send around. These messages are functionally accessed
by going through the buffers maintained by the network entities.
The patch also rectifies some of the bugs found in coherence protocols while
testing the patch.

With this patch applied, functional writes always succeed. But functional
reads can still fail.

1 files changed, 46 insertions, 1 deletions

diff --git a/src/mem/protocol/MOESI_CMP_token-msg.sm b/src/mem/protocol/MOESI_CMP_token-msg.sm
index b1c3f4580..6a8d6c6bc 100644
--- a/src/mem/protocol/MOESI_CMP_token-msg.sm
+++ b/src/mem/protocol/MOESI_CMP_token-msg.sm
@@ -1,4 +1,3 @@
-
 /*
  * Copyright (c) 1999-2005 Mark D. Hill and David A. Wood
  * All rights reserved.
@@ -66,6 +65,16 @@ structure(PersistentMsg, desc="...", interface="NetworkMessage") {
   MessageSizeType MessageSize, desc="size category of the message";
   RubyAccessMode AccessMode,    desc="user/supervisor access type";
   PrefetchBit Prefetch,         desc="Is this a prefetch request";
+
+  bool functionalRead(Packet *pkt) {
+    // No data in persistent messages
+    return false;
+  }
+
+  bool functionalWrite(Packet *pkt) {
+    // No data in persistent messages
+    return false;
+  }
 }
 
 // RequestMsg
@@ -79,6 +88,16 @@ structure(RequestMsg, desc="...", interface="NetworkMessage") {
   MessageSizeType MessageSize, desc="size category of the message";
   RubyAccessMode AccessMode,    desc="user/supervisor access type";
   PrefetchBit Prefetch,         desc="Is this a prefetch request";
+
+  bool functionalRead(Packet *pkt) {
+    // No data in request messages
+    return false;
+  }
+
+  bool functionalWrite(Packet *pkt) {
+    // No data in request messages
+    return false;
+  }
 }
 
 // ResponseMsg
@@ -91,6 +110,16 @@ structure(ResponseMsg, desc="...", interface="NetworkMessage") {
   DataBlock DataBlk,           desc="data for the cache line";
   bool Dirty,                  desc="Is the data dirty (different than memory)?";
   MessageSizeType MessageSize, desc="size category of the message";
+
+  bool functionalRead(Packet *pkt) {
+    // No check being carried out on the message type. Would be added later.
+    return testAndRead(Address, DataBlk, pkt);
+  }
+
+  bool functionalWrite(Packet *pkt) {
+    // No check required since all messages are written.
+    return testAndWrite(Address, DataBlk, pkt);
+  }
 }
 
 enumeration(DMARequestType, desc="...", default="DMARequestType_NULL") {
@@ -114,6 +143,14 @@ structure(DMARequestMsg, desc="...", interface="NetworkMessage") {
   DataBlock DataBlk,         desc="DataBlk attached to this request";
   int Len,                   desc="The length of the request";
   MessageSizeType MessageSize, desc="size category of the message";
+
+  bool functionalRead(Packet *pkt) {
+    return false;
+  }
+
+  bool functionalWrite(Packet *pkt) {
+    return testAndWrite(LineAddress, DataBlk, pkt);
+  }
 }
 
 structure(DMAResponseMsg, desc="...", interface="NetworkMessage") {
@@ -123,4 +160,12 @@ structure(DMAResponseMsg, desc="...", interface="NetworkMessage") {
   NetDest Destination,       desc="Destination";
   DataBlock DataBlk,         desc="DataBlk attached to this request";
   MessageSizeType MessageSize, desc="size category of the message";
+
+  bool functionalRead(Packet *pkt) {
+    return false;
+  }
+
+  bool functionalWrite(Packet *pkt) {
+    return testAndWrite(LineAddress, DataBlk, pkt);
+  }
 }