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.

2 files changed, 17 insertions, 14 deletions

diff --git a/src/cpu/testers/rubytest/RubyTester.cc b/src/cpu/testers/rubytest/RubyTester.cc
index 70ee40aed..e1942cf61 100644
--- a/src/cpu/testers/rubytest/RubyTester.cc
+++ b/src/cpu/testers/rubytest/RubyTester.cc
@@ -92,18 +92,19 @@ RubyTester::init()
     m_checkTable_ptr = new CheckTable(m_num_cpu_sequencers, this);
 }
 
-Port *
-RubyTester::getPort(const std::string &if_name, int idx)
+MasterPort &
+RubyTester::getMasterPort(const std::string &if_name, int idx)
 {
     if (if_name != "cpuPort") {
-        panic("RubyTester::getPort: unknown port %s requested\n", if_name);
-    }
+        // pass it along to our super class
+        return MemObject::getMasterPort(if_name, idx);
+    } else {
+        if (idx >= static_cast<int>(ports.size())) {
+            panic("RubyTester::getMasterPort: unknown index %d\n", idx);
+        }
 
-    if (idx >= static_cast<int>(ports.size())) {
-        panic("RubyTester::getPort: unknown index %d requested\n", idx);
+        return *ports[idx];
     }
-
-    return ports[idx];
 }
 
 Tick
@@ -135,7 +136,7 @@ RubyTester::CpuPort::recvTiming(PacketPtr pkt)
     return true;
 }
 
-Port*
+MasterPort*
 RubyTester::getCpuPort(int idx)
 {
     assert(idx >= 0 && idx < ports.size());
diff --git a/src/cpu/testers/rubytest/RubyTester.hh b/src/cpu/testers/rubytest/RubyTester.hh
index e8cf4c874..b24dddd83 100644
--- a/src/cpu/testers/rubytest/RubyTester.hh
+++ b/src/cpu/testers/rubytest/RubyTester.hh
@@ -45,23 +45,24 @@
 class RubyTester : public MemObject
 {
   public:
-    class CpuPort : public Port
+    class CpuPort : public MasterPort
     {
       private:
         RubyTester *tester;
 
       public:
         CpuPort(const std::string &_name, RubyTester *_tester, int _idx)
-            : Port(_name, _tester), tester(_tester), idx(_idx)
+            : MasterPort(_name, _tester), tester(_tester), idx(_idx)
         {}
 
         int idx;
 
       protected:
         virtual bool recvTiming(PacketPtr pkt);
+        virtual void recvRetry()
+        { panic("%s does not expect a retry\n", name()); }
         virtual Tick recvAtomic(PacketPtr pkt);
         virtual void recvFunctional(PacketPtr pkt) { }
-        virtual void recvRangeChange() { }
     };
 
     struct SenderState : public Packet::SenderState
@@ -86,9 +87,10 @@ class RubyTester : public MemObject
     RubyTester(const Params *p);
     ~RubyTester();
 
-    virtual Port *getPort(const std::string &if_name, int idx = -1);
+    virtual MasterPort &getMasterPort(const std::string &if_name,
+                                      int idx = -1);
 
-    Port* getCpuPort(int idx);
+    MasterPort* getCpuPort(int idx);
 
     virtual void init();