MEM: Introduce the master/slave port sub-classes in C++

This patch introduces the notion of a master and slave port in the C++
code, thus bringing the previous classification from the Python
classes into the corresponding simulation objects and memory objects.

The patch enables us to classify behaviours into the two bins and add
assumptions and enfore compliance, also simplifying the two
interfaces. As a starting point, isSnooping is confined to a master
port, and getAddrRanges to slave ports. More of these specilisations
are to come in later patches.

The getPort function is not getMasterPort and getSlavePort, and
returns a port reference rather than a pointer as NULL would never be
a valid return value. The default implementation of these two
functions is placed in MemObject, and calls fatal.

The one drawback with this specific patch is that it requires some
code duplication, e.g. QueuedPort becomes QueuedMasterPort and
QueuedSlavePort, and BusPort becomes BusMasterPort and BusSlavePort
(avoiding multiple inheritance). With the later introduction of the
port interfaces, moving the functionality outside the port itself, a
lot of the duplicated code will disappear again.

1 files changed, 6 insertions, 15 deletions

diff --git a/src/mem/bridge.hh b/src/mem/bridge.hh
index 3e0040514..e7dbc0a28 100644
--- a/src/mem/bridge.hh
+++ b/src/mem/bridge.hh
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011 ARM Limited
+ * Copyright (c) 2011-2012 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -122,7 +122,7 @@ class Bridge : public MemObject
      * is responsible for. The slave port also has a buffer for the
      * responses not yet sent.
      */
-    class BridgeSlavePort : public Port
+    class BridgeSlavePort : public SlavePort
     {
 
       private:
@@ -244,11 +244,6 @@ class Bridge : public MemObject
             pass it to the bridge. */
         virtual void recvFunctional(PacketPtr pkt);
 
-        /**
-         * When receiving a range change on the slave side do nothing.
-         */
-        virtual void recvRangeChange();
-
         /** When receiving a address range request the peer port,
             pass it to the bridge. */
         virtual AddrRangeList getAddrRanges();
@@ -260,7 +255,7 @@ class Bridge : public MemObject
      * responses. The master port has a buffer for the requests not
      * yet sent.
      */
-    class BridgeMasterPort : public Port
+    class BridgeMasterPort : public MasterPort
     {
 
       private:
@@ -371,11 +366,6 @@ class Bridge : public MemObject
         /** When receiving a Functional request from the peer port,
             pass it to the bridge. */
         virtual void recvFunctional(PacketPtr pkt);
-
-        /**
-         * When receiving a range change, pass it through the bridge.
-         */
-        virtual void recvRangeChange();
     };
 
     /** Slave port of the bridge. */
@@ -396,8 +386,9 @@ class Bridge : public MemObject
   public:
     const Params *params() const { return _params; }
 
-    /** A function used to return the port associated with this bus object. */
-    virtual Port *getPort(const std::string &if_name, int idx = -1);
+    virtual MasterPort& getMasterPort(const std::string& if_name,
+                                      int idx = -1);
+    virtual SlavePort& getSlavePort(const std::string& if_name, int idx = -1);
 
     virtual void init();