mem-ruby: Fix Ruby handling of functional requests

This patch addresses multiple cases:

- When a controller has read/write permissions while others have read
  only permissions, the one with r/w permissions performs the read as
  the others may have stale data
- When controllers only have lines with stale or busy access permissions,
  a valid copy of the line may be in a message in transit in the network
  or in a message buffer (not seen by the controller yet). In this case,
  we forward the functional request accordingly.
- Sequencer messages should not accept functional reads
- Functional writes also update the packet data on the sequencer
  outstanding request lists and the cpu-side response queue.

Change-Id: I6b0656f1a2b81d41bdcf6c783dfa522a77393981
Signed-off-by: Tiago Mück <tiago.muck@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/22022
Tested-by: Gem5 Cloud Project GCB service account <345032938727@cloudbuild.gserviceaccount.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: John Alsop <johnathan.alsop@amd.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>

src/mem/slicc/symbols/StateMachine.py

@@ -323,6 +323,7 @@ class $c_ident : public AbstractController
 
     void recordCacheTrace(int cntrl, CacheRecorder* tr);
     Sequencer* getCPUSequencer() const;
+    DMASequencer* getDMASequencer() const;
     GPUCoalescer* getGPUCoalescer() const;
 
     bool functionalReadBuffers(PacketPtr&);
@@ -702,6 +703,12 @@ $c_ident::init()
                 assert(param.pointer)
                 seq_ident = "m_%s_ptr" % param.ident
 
+        dma_seq_ident = "NULL"
+        for param in self.config_parameters:
+            if param.ident == "dma_sequencer":
+                assert(param.pointer)
+                dma_seq_ident = "m_%s_ptr" % param.ident
+
         coal_ident = "NULL"
         for param in self.config_parameters:
             if param.ident == "coalescer":
@@ -728,6 +735,28 @@ $c_ident::getCPUSequencer() const
 {
     return NULL;
 }
+''')
+
+        if dma_seq_ident != "NULL":
+            code('''
+DMASequencer*
+$c_ident::getDMASequencer() const
+{
+    if (NULL != $dma_seq_ident) {
+        return $dma_seq_ident;
+    } else {
+        return NULL;
+    }
+}
+''')
+        else:
+            code('''
+
+DMASequencer*
+$c_ident::getDMASequencer() const
+{
+    return NULL;
+}
 ''')
 
         if coal_ident != "NULL":