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, 1 insertions, 1 deletions

diff --git a/src/cpu/testers/networktest/NetworkTest.py b/src/cpu/testers/networktest/NetworkTest.py
index b2eda9aa2..7d6ed576b 100644
--- a/src/cpu/testers/networktest/NetworkTest.py
+++ b/src/cpu/testers/networktest/NetworkTest.py
@@ -41,5 +41,5 @@ class NetworkTest(MemObject):
     traffic_type = Param.Counter(0, "Traffic type: uniform random, tornado, bit complement")
     inj_rate = Param.Float(0.1, "Packet injection rate")
     precision = Param.Int(3, "Number of digits of precision after decimal point")
-    test = Port("Port to the memory system to test")
+    test = MasterPort("Port to the memory system to test")
     system = Param.System(Parent.any, "System we belong to")