systemc: Add Port types for initiator and target sockets.

These make it clear that a port represents a TLM socket, what direction
it faces, and what its width is.

Change-Id: Idcbea2b9b053f1e0685e011bc2c7de2468fb25b2
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18172
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Gabe Black <gabeblack@google.com>

src/systemc/SConscript

@@ -33,3 +33,5 @@ if not env['USE_SYSTEMC']:
 env.UseSystemcCheck(warn=True)
 
 env.Append(CPPPATH=Dir('ext'))
+
+SimObject('Tlm.py')

src/systemc/Tlm.py

@@ -0,0 +1,67 @@
+# Copyright 2019 Google, Inc.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met: redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer;
+# redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the distribution;
+# neither the name of the copyright holders nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+# Authors: Gabe Black
+
+from m5.params import Port, VectorPort
+
+def TLM_TARGET_ROLE(width):
+    return 'TLM TARGET %d' % width
+
+def TLM_INITIATOR_ROLE(width):
+    return 'TLM INITIATOR %d' % width
+
+class TlmTargetSocket(Port):
+    def __init__(self, width, desc):
+        my_role = TLM_TARGET_ROLE(width)
+        peer_role = TLM_INITIATOR_ROLE(width)
+        Port.compat(my_role, peer_role)
+
+        super(TlmTargetSocket, self).__init__(my_role, desc)
+
+class VectorTlmTargetSocket(VectorPort):
+    def __init__(self, width, desc):
+        my_role = TLM_TARGET_ROLE(width)
+        peer_role = TLM_INITIATOR_ROLE(width)
+        Port.compat(my_role, peer_role)
+
+        super(VectorTlmTargetSocket, self).__init__(my_role, desc)
+
+class TlmInitiatorSocket(Port):
+    def __init__(self, width, desc):
+        my_role = TLM_INITIATOR_ROLE(width)
+        peer_role = TLM_TARGET_ROLE(width)
+        Port.compat(my_role, peer_role)
+
+        super(TlmInitiatorSocket, self).__init__(my_role, desc, is_source=True)
+
+class VectorTlmInitiatorSocket(VectorPort):
+    def __init__(self, width, desc):
+        my_role = TLM_INITIATOR_ROLE(width)
+        peer_role = TLM_TARGET_ROLE(width)
+        Port.compat(my_role, peer_role)
+
+        super(VectorTlmInitiatorSocket, self).__init__(
+                my_role, desc, is_source=True)