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, 42 insertions, 2 deletions

diff --git a/src/mem/protocol/MI_example-msg.sm b/src/mem/protocol/MI_example-msg.sm
index 2fb1c48ba..0645371f6 100644
--- a/src/mem/protocol/MI_example-msg.sm
+++ b/src/mem/protocol/MI_example-msg.sm
@@ -31,11 +31,9 @@ enumeration(CoherenceRequestType, desc="...") {
   GETX,      desc="Get eXclusive";
   GETS,      desc="Get Shared";
   PUTX,      desc="Put eXclusive";
-  PUTO,      desc="Put Owned";
   WB_ACK,    desc="Writeback ack";
   WB_NACK,   desc="Writeback neg. ack";
   INV,       desc="Invalidation";
-  FWD,      desc="Generic FWD";
 }
 
 // CoherenceResponseType
@@ -59,6 +57,20 @@ structure(RequestMsg, desc="...", interface="NetworkMessage") {
   NetDest Destination,             desc="Multicast destination mask";
   DataBlock DataBlk,           desc="data for the cache line";
   MessageSizeType MessageSize, desc="size category of the message";
+
+  bool functionalRead(Packet *pkt) {
+    // Valid data block is only present in PUTX messages
+    if (Type == CoherenceRequestType:PUTX) {
+        return testAndRead(Address, DataBlk, pkt);
+    }
+    return false;
+  }
+
+  bool functionalWrite(Packet *pkt) {
+    // No check on message type required since the protocol should read
+    // data block from only those messages that contain valid data
+    return testAndWrite(Address, DataBlk, pkt);
+  }
 }
 
 // ResponseMsg (and also unblock requests)
@@ -70,6 +82,18 @@ 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) {
+    // A check on message type should appear here so that only those
+    // messages that contain data
+    return testAndRead(Address, DataBlk, pkt);
+  }
+
+  bool functionalWrite(Packet *pkt) {
+    // No check on message type required since the protocol should read
+    // data block from only those messages that contain valid data
+    return testAndWrite(Address, DataBlk, pkt);
+  }
 }
 
 enumeration(DMARequestType, desc="...", default="DMARequestType_NULL") {
@@ -93,6 +117,14 @@ 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 testAndRead(LineAddress, DataBlk, pkt);
+  }
+
+  bool functionalWrite(Packet *pkt) {
+    return testAndWrite(LineAddress, DataBlk, pkt);
+  }
 }
 
 structure(DMAResponseMsg, desc="...", interface="NetworkMessage") {
@@ -102,4 +134,12 @@ 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 testAndRead(LineAddress, DataBlk, pkt);
+  }
+
+  bool functionalWrite(Packet *pkt) {
+    return testAndWrite(LineAddress, DataBlk, pkt);
+  }
 }