Port: Stricter port bind/unbind semantics

This patch tightens up the semantics around port binding and checks
that the ports that are being bound are currently not connected, and
similarly connected before unbind is called.

The patch consequently also changes the order of the unbind and bind
for the switching of CPUs to ensure that the rules are adhered
to. Previously the ports would be "over-written" without any check.

There are no changes in behaviour due to this patch, and the only
place where the unbind functionality is used is in the CPU.

1 files changed, 22 insertions, 3 deletions

diff --git a/src/mem/port.hh b/src/mem/port.hh
index eac92791e..631725ce1 100644
--- a/src/mem/port.hh
+++ b/src/mem/port.hh
@@ -140,8 +140,17 @@ class MasterPort : public Port
                PortID id = InvalidPortID);
     virtual ~MasterPort();
 
-    void unBind();
+    /**
+     * Bind this master port to a slave port. This also does the
+     * mirror action and binds the slave port to the master port.
+     */
     void bind(SlavePort& slave_port);
+
+    /**
+     * Unbind this master port and the associated slave port.
+     */
+    void unbind();
+
     SlavePort& getSlavePort() const;
     bool isConnected() const;
 
@@ -298,8 +307,6 @@ class SlavePort : public Port
               PortID id = InvalidPortID);
     virtual ~SlavePort();
 
-    void unBind();
-    void bind(MasterPort& master_port);
     MasterPort& getMasterPort() const;
     bool isConnected() const;
 
@@ -387,6 +394,18 @@ class SlavePort : public Port
   protected:
 
     /**
+     * Called by the master port to unbind. Should never be called
+     * directly.
+     */
+    void unbind();
+
+    /**
+     * Called by the master port to bind. Should never be called
+     * directly.
+     */
+    void bind(MasterPort& master_port);
+
+    /**
      * Receive an atomic request packet from the master port.
      */
     virtual Tick recvAtomic(PacketPtr pkt) = 0;