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, 40 insertions, 0 deletions

diff --git a/src/mem/protocol/MOESI_CMP_directory-msg.sm b/src/mem/protocol/MOESI_CMP_directory-msg.sm
index 7b203537f..e428be7f7 100644
--- a/src/mem/protocol/MOESI_CMP_directory-msg.sm
+++ b/src/mem/protocol/MOESI_CMP_directory-msg.sm
@@ -71,6 +71,16 @@ enumeration(TriggerType, desc="...") {
 structure(TriggerMsg, desc="...", interface="Message") {
   Address Address,             desc="Physical address for this request";
   TriggerType Type,            desc="Type of trigger";
+
+  bool functionalRead(Packet *pkt) {
+    // Trigger message does not hold data
+    return false;
+  }
+
+  bool functionalWrite(Packet *pkt) {
+    // Trigger message does not hold data
+    return false;
+  }
 }
 
 // RequestMsg (and also forwarded requests)
@@ -86,6 +96,20 @@ 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) {
+    // Read only those messages that contain the data
+    if (Type == CoherenceRequestType:DMA_READ ||
+        Type == CoherenceRequestType:DMA_WRITE) {
+        return testAndRead(Address, DataBlk, pkt);
+    }
+    return false;
+  }
+
+  bool functionalWrite(Packet *pkt) {
+    // No check required since all messages are written
+    return testAndWrite(Address, DataBlk, pkt);
+  }
 }
 
 // ResponseMsg (and also unblock requests)
@@ -99,4 +123,20 @@ structure(ResponseMsg, desc="...", interface="NetworkMessage") {
   bool Dirty,                  desc="Is the data dirty (different than memory)?";
   int Acks,                    desc="How many acks to expect";
   MessageSizeType MessageSize, desc="size category of the message";
+
+  bool functionalRead(Packet *pkt) {
+    // Read only those messages that contain the data
+    if (Type == CoherenceResponseType:DATA ||
+        Type == CoherenceResponseType:DATA_EXCLUSIVE ||
+        Type == CoherenceResponseType:WRITEBACK_CLEAN_DATA ||
+        Type == CoherenceResponseType:WRITEBACK_DIRTY_DATA) {
+        return testAndRead(Address, DataBlk, pkt);
+    }
+    return false;
+  }
+
+  bool functionalWrite(Packet *pkt) {
+    // No check required since all messages are written
+    return testAndWrite(Address, DataBlk, pkt);
+  }
 }