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, 4 insertions, 3 deletions

diff --git a/src/mem/ruby/system/Sequencer.py b/src/mem/ruby/system/Sequencer.py
index ddf760f7b..b1e17e052 100644
--- a/src/mem/ruby/system/Sequencer.py
+++ b/src/mem/ruby/system/Sequencer.py
@@ -34,11 +34,12 @@ from MemObject import MemObject
 class RubyPort(MemObject):
     type = 'RubyPort'
     abstract = True
-    port = VectorPort("M5 port")
+    slave = VectorSlavePort("CPU slave port")
+    master = VectorMasterPort("CPU master port")
     version = Param.Int(0, "")
-    pio_port = Port("Ruby_pio_port")
+    pio_port = MasterPort("Ruby_pio_port")
     physmem = Param.PhysicalMemory("")
-    physMemPort = Port("port to physical memory")
+    physMemPort = MasterPort("port to physical memory")
     using_ruby_tester = Param.Bool(False, "")
     using_network_tester = Param.Bool(False, "")
     access_phys_mem = Param.Bool(True,