mem: Move ruby protocols into a directory called ruby_protocol.

Now that the gem5 protocols are split out, it would be nice to put them
in their own protocol directory. It's also confusing to have files
called *_protocol which are not in the protocol directory.

Change-Id: I7475ee111630050a2421816dfd290921baab9f71
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20230
Reviewed-by: Gabe Black <gabeblack@google.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>

mem: Standardize mem folder header guards

Standardize all header guards in the mem directory according to the most
frequent patterns. In general they have the form:
mem: __FOLDER_TREE_FILE_NAME_HH__
ruby: __FOLDER_TREE_FILENAME_HH__

Change-Id: I983853e292deb302becf151bf0e970057dc24774
Reviewed-on: https://gem5-review.googlesource.com/7881
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>

ruby: Rename pkt to m_pkt so it may be accessed via SLICC

Allow usage of packet class in ruby for convenience purposes. This may be
used to access members of the packet/request class (e.g., via helper
functions) and/or push protocol specific information to the packets
SenderState without needing to modify SLICC types and protocols in multiple
locations.

mem: write combining for ruby protocols

This patch adds support for write-combining in ruby.

mem: misc flags for AMD gpu model

This patch add support to mark memory requests/packets with attributes defined
in HSA, such as memory order and scope.

ruby: replace Address by Addr
This patch eliminates the type Address defined by the ruby memory system.
This memory system would now use the type Addr that is in use by the
rest of the system.

base: Declare a type for context IDs

Context IDs used to be declared as ad hoc (usually as int). This
changeset introduces a typedef for ContextIDs and a constant for
invalid context IDs.

mem: Use shared_ptr for Ruby Message classes

This patch transitions the Ruby Message and its derived classes from
the ad-hoc RefCountingPtr to the c++11 shared_ptr. There are no
changes in behaviour, and the code modifications are mainly replacing
"new" with "make_shared".

The cloning of derived messages is slightly changed as they previously
relied on overriding the base-class through covariant return types.

ruby: enable multiple clock domains
This patch allows ruby to have multiple clock domains. As I understand
with this patch, controllers can have different frequencies. The entire
network needs to run at a single frequency.

The idea is that with in an object, time is treated in terms of cycles.
But the messages that are passed from one entity to another should contain
the time in Ticks. As of now, this is only true for the message buffers,
but not for the links in the network. As I understand the code, all the
entities in different networks (simple, garnet-fixed, garnet-flexible) should
be clocked at the same frequency.

Another problem is that the directory controller has to operate at the same
frequency as the ruby system. This is because the memory controller does
not make use of the Message Buffer, and instead implements a buffer of its
own. So, it has no idea of the frequency at which the directory controller
is operating and uses ruby system's frequency for scheduling events.

ruby: replace Time with Cycles in Message class
Concomitant changes are being committed as well, including the io operator<<
for the Cycles class.

Ruby: remove reference to g_system_ptr from class Message
This patch was initiated so as to remove reference to g_system_ptr,
the pointer to Ruby System that is used for getting the current time.
That simple change actual requires changing a lot many things in slicc and
garnet. All these changes are related to how time is handled.

In most of the places, g_system_ptr has been replaced by another clock
object. The changes have been done under the assumption that all the
components in the memory system are on the same clock frequency, but the
actual clocks might be distributed.

ruby: improved support for functional accesses
This patch adds support to different entities in the ruby memory system
for more reliable functional read/write accesses. Only the simple network
has been augmented as of now. Later on Garnet will also support functional
accesses.
The patch adds functional access code to all the different types of messages
that protocols can send around. These messages are functionally accessed
by going through the buffers maintained by the network entities.
The patch also rectifies some of the bugs found in coherence protocols while
testing the patch.

With this patch applied, functional writes always succeed. But functional
reads can still fail.

Ruby: remove some unused stuff from SLICC files

includes: sort all includes

Ruby: pass Packet->Req->contextId() to Ruby.
It is useful for Ruby to understand from whence request packets came.
This has all request packets going into Ruby pass the contextId value, if
it exists. This supplants the old libruby proc_id value passed around in
all the Messages, so I've also removed the unused unsigned proc_id; member
generated by SLICC for all Message types.

Ruby: Remove CacheMsg class from SLICC
The goal of the patch is to do away with the CacheMsg class currently in use
in coherence protocols. In place of CacheMsg, the RubyRequest class will used.
This class is already present in slicc_interface/RubyRequest.hh. In fact,
objects of class CacheMsg are generated by copying values from a RubyRequest
object.

Ruby: Convert CacheRequestType to RubyRequestType
This patch converts CacheRequestType to RubyRequestType so that both the
protocol dependent and independent code makes use of the same request type.

Ruby: Convert AccessModeType to RubyAccessMode
This patch converts AccessModeType to RubyAccessMode so that both the
protocol dependent and independent code uses the same access mode.

Ruby: Remove libruby
This patch removes libruby_internal.hh, libruby.hh and libruby.cc. It moves
the contents to libruby.hh to RubyRequest.hh and RubyRequest.cc files.