MEM: Introduce the master/slave port roles in the Python classes

This patch classifies all ports in Python as either Master or Slave
and enforces a binding of master to slave. Conceptually, a master (such
as a CPU or DMA port) issues requests, and receives responses, and
conversely, a slave (such as a memory or a PIO device) receives
requests and sends back responses. Currently there is no
differentiation between coherent and non-coherent masters and slaves.

The classification as master/slave also involves splitting the dual
role port of the bus into a master and slave port and updating all the
system assembly scripts to use the appropriate port. Similarly, the
interrupt devices have to have their int_port split into a master and
slave port. The intdev and its children have minimal changes to
facilitate the extra port.

Note that this patch does not enforce any port typing in the C++
world, it merely ensures that the Python objects have a notion of the
port roles and are connected in an appropriate manner. This check is
carried when two ports are connected, e.g. bus.master =
memory.port. The following patches will make use of the
classifications and specialise the C++ ports into masters and slaves.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/dev/Ethernet.py b/src/dev/Ethernet.py
index 539e4ea9b..91d4e230e 100644
--- a/src/dev/Ethernet.py
+++ b/src/dev/Ethernet.py
@@ -37,8 +37,8 @@ class EtherObject(SimObject):
 
 class EtherLink(EtherObject):
     type = 'EtherLink'
-    int0 = Port("interface 0")
-    int1 = Port("interface 1")
+    int0 = SlavePort("interface 0")
+    int1 = SlavePort("interface 1")
     delay = Param.Latency('0us', "packet transmit delay")
     delay_var = Param.Latency('0ns', "packet transmit delay variability")
     speed = Param.NetworkBandwidth('1Gbps', "link speed")
@@ -64,7 +64,7 @@ class EtherDump(SimObject):
 class EtherDevice(PciDevice):
     type = 'EtherDevice'
     abstract = True
-    interface = Port("Ethernet Interface")
+    interface = MasterPort("Ethernet Interface")
 
 class IGbE(EtherDevice):
     # Base class for two IGbE adapters listed above