mem: Put gem5 protocols in their own directory.

This reduces clutter in the src/mem directory, and makes it clear that
those protocols are for the classic gem5 memory system, not ruby, TLM,
etc.

Change-Id: I6cf6b21134d82f4f01991e4fe92dbea8c7e82081
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20231
Tested-by: kokoro <noreply+kokoro@google.com>
Maintainer: Gabe Black <gabeblack@google.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>

7 files changed, 677 insertions, 0 deletions

diff --git a/src/mem/protocol/SConscript b/src/mem/protocol/SConscript
new file mode 100644
index 000000000..abab5cc7f
--- /dev/null
+++ b/src/mem/protocol/SConscript
@@ -0,0 +1,32 @@
+# 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
+
+Import('*')
+
+Source('atomic.cc')
+Source('functional.cc')
+Source('timing.cc')
diff --git a/src/mem/protocol/atomic.cc b/src/mem/protocol/atomic.cc
new file mode 100644
index 000000000..3ddd71589
--- /dev/null
+++ b/src/mem/protocol/atomic.cc
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2012,2015,2017 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Copyright (c) 2002-2005 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * 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: Steve Reinhardt
+ *          Andreas Hansson
+ *          William Wang
+ */
+
+#include "mem/protocol/atomic.hh"
+
+#include "base/trace.hh"
+
+/* The request protocol. */
+
+Tick
+AtomicRequestProtocol::send(AtomicResponseProtocol *peer, PacketPtr pkt)
+{
+    assert(pkt->isRequest());
+    return peer->recvAtomic(pkt);
+}
+
+Tick
+AtomicRequestProtocol::sendBackdoor(AtomicResponseProtocol *peer,
+        PacketPtr pkt, MemBackdoorPtr &backdoor)
+{
+    assert(pkt->isRequest());
+    return peer->recvAtomicBackdoor(pkt, backdoor);
+}
+
+/* The response protocol. */
+
+Tick
+AtomicResponseProtocol::sendSnoop(AtomicRequestProtocol *peer, PacketPtr pkt)
+{
+    assert(pkt->isRequest());
+    return peer->recvAtomicSnoop(pkt);
+}
diff --git a/src/mem/protocol/atomic.hh b/src/mem/protocol/atomic.hh
new file mode 100644
index 000000000..bbbd408d0
--- /dev/null
+++ b/src/mem/protocol/atomic.hh
@@ -0,0 +1,120 @@
+/*
+ * Copyright (c) 2011-2012,2015,2017 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Copyright (c) 2002-2005 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * 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: Ron Dreslinski
+ *          Andreas Hansson
+ *          William Wang
+ */
+
+#ifndef __MEM_GEM5_PROTOCOL_ATOMIC_HH__
+#define __MEM_GEM5_PROTOCOL_ATOMIC_HH__
+
+#include "mem/backdoor.hh"
+#include "mem/packet.hh"
+
+class AtomicResponseProtocol;
+
+class AtomicRequestProtocol
+{
+    friend class AtomicResponseProtocol;
+
+  protected:
+    /**
+     * Send an atomic request packet, where the data is moved and the
+     * state is updated in zero time, without interleaving with other
+     * memory accesses.
+     *
+     * @param peer Peer to send packet to.
+     * @param pkt Packet to send.
+     *
+     * @return Estimated latency of access.
+     */
+    Tick send(AtomicResponseProtocol *peer, PacketPtr pkt);
+
+    /**
+     * Send an atomic request packet like above, but also request a backdoor
+     * to the data being accessed.
+     *
+     * @param peer Peer to send packet to.
+     * @param pkt Packet to send.
+     * @param backdoor Can be set to a back door pointer by the target to let
+     *        caller have direct access to the requested data.
+     *
+     * @return Estimated latency of access.
+     */
+    Tick sendBackdoor(AtomicResponseProtocol *peer, PacketPtr pkt,
+                      MemBackdoorPtr &backdoor);
+
+    /**
+     * Receive an atomic snoop request packet from our peer.
+     */
+    virtual Tick recvAtomicSnoop(PacketPtr pkt) = 0;
+};
+
+class AtomicResponseProtocol
+{
+    friend class AtomicRequestProtocol;
+
+  protected:
+    /**
+     * Send an atomic snoop request packet, where the data is moved
+     * and the state is updated in zero time, without interleaving
+     * with other memory accesses.
+     *
+     * @param peer Peer to send packet to.
+     * @param pkt Snoop packet to send.
+     *
+     * @return Estimated latency of access.
+     */
+    Tick sendSnoop(AtomicRequestProtocol *peer, PacketPtr pkt);
+
+    /**
+     * Receive an atomic request packet from the peer.
+     */
+    virtual Tick recvAtomic(PacketPtr pkt) = 0;
+
+    /**
+     * Receive an atomic request packet from the peer, and optionally
+     * provide a backdoor to the data being accessed.
+     */
+    virtual Tick recvAtomicBackdoor(
+            PacketPtr pkt, MemBackdoorPtr &backdoor) = 0;
+};
+
+#endif //__MEM_GEM5_PROTOCOL_ATOMIC_HH__
diff --git a/src/mem/protocol/functional.cc b/src/mem/protocol/functional.cc
new file mode 100644
index 000000000..6ae7c626d
--- /dev/null
+++ b/src/mem/protocol/functional.cc
@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2012,2015,2017 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Copyright (c) 2002-2005 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * 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: Steve Reinhardt
+ *          Andreas Hansson
+ *          William Wang
+ */
+
+#include "mem/protocol/functional.hh"
+
+/* The request protocol. */
+
+void
+FunctionalRequestProtocol::send(
+        FunctionalResponseProtocol *peer, PacketPtr pkt) const
+{
+    assert(pkt->isRequest());
+    return peer->recvFunctional(pkt);
+}
+
+/* The response protocol. */
+
+void
+FunctionalResponseProtocol::sendSnoop(
+        FunctionalRequestProtocol *peer, PacketPtr pkt) const
+{
+    assert(pkt->isRequest());
+    return peer->recvFunctionalSnoop(pkt);
+}
diff --git a/src/mem/protocol/functional.hh b/src/mem/protocol/functional.hh
new file mode 100644
index 000000000..ffd27a488
--- /dev/null
+++ b/src/mem/protocol/functional.hh
@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2011-2012,2015,2017 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Copyright (c) 2002-2005 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * 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: Ron Dreslinski
+ *          Andreas Hansson
+ *          William Wang
+ */
+
+#ifndef __MEM_GEM5_PROTOCOL_FUNCTIONAL_HH__
+#define __MEM_GEM5_PROTOCOL_FUNCTIONAL_HH__
+
+#include "mem/packet.hh"
+
+class FunctionalResponseProtocol;
+
+class FunctionalRequestProtocol
+{
+    friend class FunctionalResponseProtocol;
+
+  protected:
+    /**
+     * Send a functional request packet, where the data is instantly
+     * updated everywhere in the memory system, without affecting the
+     * current state of any block or moving the block.
+     *
+     * @param pkt Packet to send.
+     */
+    void send(FunctionalResponseProtocol *peer, PacketPtr pkt) const;
+
+    /**
+     * Receive a functional snoop request packet from the peer.
+     */
+    virtual void recvFunctionalSnoop(PacketPtr pkt) = 0;
+};
+
+class FunctionalResponseProtocol
+{
+    friend class FunctionalRequestProtocol;
+
+  protected:
+    /**
+     * Send a functional snoop request packet, where the data is
+     * instantly updated everywhere in the memory system, without
+     * affecting the current state of any block or moving the block.
+     *
+     * @param pkt Snoop packet to send.
+     */
+    void sendSnoop(FunctionalRequestProtocol *peer, PacketPtr pkt) const;
+
+    /**
+     * Receive a functional request packet from the peer.
+     */
+    virtual void recvFunctional(PacketPtr pkt) = 0;
+};
+
+#endif //__MEM_GEM5_PROTOCOL_FUNCTIONAL_HH__
diff --git a/src/mem/protocol/timing.cc b/src/mem/protocol/timing.cc
new file mode 100644
index 000000000..b3efcfbfc
--- /dev/null
+++ b/src/mem/protocol/timing.cc
@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2012,2015,2017 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Copyright (c) 2002-2005 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * 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: Steve Reinhardt
+ *          Andreas Hansson
+ *          William Wang
+ */
+
+#include "mem/protocol/timing.hh"
+
+/* The request protocol. */
+
+bool
+TimingRequestProtocol::sendReq(TimingResponseProtocol *peer, PacketPtr pkt)
+{
+    assert(pkt->isRequest());
+    return peer->recvTimingReq(pkt);
+}
+
+bool
+TimingRequestProtocol::trySend(
+        TimingResponseProtocol *peer, PacketPtr pkt) const
+{
+  assert(pkt->isRequest());
+  return peer->tryTiming(pkt);
+}
+
+bool
+TimingRequestProtocol::sendSnoopResp(
+        TimingResponseProtocol *peer, PacketPtr pkt)
+{
+    assert(pkt->isResponse());
+    return peer->recvTimingSnoopResp(pkt);
+}
+
+void
+TimingRequestProtocol::sendRetryResp(TimingResponseProtocol *peer)
+{
+    peer->recvRespRetry();
+}
+
+/* The response protocol. */
+
+bool
+TimingResponseProtocol::sendResp(TimingRequestProtocol *peer, PacketPtr pkt)
+{
+    assert(pkt->isResponse());
+    return peer->recvTimingResp(pkt);
+}
+
+void
+TimingResponseProtocol::sendSnoopReq(
+        TimingRequestProtocol *peer, PacketPtr pkt)
+{
+    assert(pkt->isRequest());
+    peer->recvTimingSnoopReq(pkt);
+}
+
+void
+TimingResponseProtocol::sendRetryReq(TimingRequestProtocol *peer)
+{
+    peer->recvReqRetry();
+}
+
+void
+TimingResponseProtocol::sendRetrySnoopResp(TimingRequestProtocol *peer)
+{
+    peer->recvRetrySnoopResp();
+}
diff --git a/src/mem/protocol/timing.hh b/src/mem/protocol/timing.hh
new file mode 100644
index 000000000..108ac9796
--- /dev/null
+++ b/src/mem/protocol/timing.hh
@@ -0,0 +1,190 @@
+/*
+ * Copyright (c) 2011-2012,2015,2017 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Copyright (c) 2002-2005 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * 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: Ron Dreslinski
+ *          Andreas Hansson
+ *          William Wang
+ */
+
+#ifndef __MEM_GEM5_PROTOCOL_TIMING_HH__
+#define __MEM_GEM5_PROTOCOL_TIMING_HH__
+
+#include "mem/packet.hh"
+
+class TimingResponseProtocol;
+
+class TimingRequestProtocol
+{
+    friend class TimingResponseProtocol;
+
+  protected:
+    /**
+     * Attempt to send a timing request to the peer by calling
+     * its corresponding receive function. If the send does not
+     * succeed, as indicated by the return value, then the sender must
+     * wait for a recvReqRetry at which point it can re-issue a
+     * sendTimingReq.
+     *
+     * @param peer Peer to send packet to.
+     * @param pkt Packet to send.
+     *
+     * @return If the send was succesful or not.
+     */
+    bool sendReq(TimingResponseProtocol *peer, PacketPtr pkt);
+
+    /**
+     * Check if the peer can handle a timing request.
+     *
+     * If the send cannot be handled at the moment, as indicated by
+     * the return value, then the sender will receive a recvReqRetry
+     * at which point it can re-issue a sendTimingReq.
+     *
+     * @param peer Peer to send packet to.
+     * @param pkt Packet to send.
+     *
+     * @return If the send was succesful or not.
+     */
+    bool trySend(TimingResponseProtocol *peer, PacketPtr pkt) const;
+
+    /**
+     * Attempt to send a timing snoop response packet to it's peer
+     * by calling its corresponding receive function. If the send
+     * does not succeed, as indicated by the return value, then the
+     * sender must wait for a recvRetrySnoop at which point it can
+     * re-issue a sendTimingSnoopResp.
+     *
+     * @param pkt Packet to send.
+     */
+    bool sendSnoopResp(TimingResponseProtocol *peer, PacketPtr pkt);
+
+    /**
+     * Send a retry to the peer that previously attempted a
+     * sendTimingResp to this protocol and failed.
+     */
+    void sendRetryResp(TimingResponseProtocol *peer);
+
+    /**
+     * Receive a timing response from the peer.
+     */
+    virtual bool recvTimingResp(PacketPtr pkt) = 0;
+
+    /**
+     * Receive a timing snoop request from the peer.
+     */
+    virtual void recvTimingSnoopReq(PacketPtr pkt) = 0;
+
+    /**
+     * Called by the peer if sendTimingReq was called on this peer (causing
+     * recvTimingReq to be called on the peer) and was unsuccessful.
+     */
+    virtual void recvReqRetry() = 0;
+
+    /**
+     * Called by the peer if sendTimingSnoopResp was called on this
+     * protocol (causing recvTimingSnoopResp to be called on the peer)
+     * and was unsuccessful.
+     */
+    virtual void recvRetrySnoopResp() = 0;
+};
+
+class TimingResponseProtocol
+{
+    friend class TimingRequestProtocol;
+
+  protected:
+    /**
+     * Attempt to send a timing response to the peer by calling
+     * its corresponding receive function. If the send does not
+     * succeed, as indicated by the return value, then the sender must
+     * wait for a recvRespRetry at which point it can re-issue a
+     * sendTimingResp.
+     *
+     * @param peer Peer to send the packet to.
+     * @param pkt Packet to send.
+     *
+     * @return If the send was succesful or not.
+    */
+    bool sendResp(TimingRequestProtocol *peer, PacketPtr pkt);
+
+    /**
+     * Attempt to send a timing snoop request packet to the peer
+     * by calling its corresponding receive function. Snoop requests
+     * always succeed and hence no return value is needed.
+     *
+     * @param peer Peer to send the packet to.
+     * @param pkt Packet to send.
+     */
+    void sendSnoopReq(TimingRequestProtocol *peer, PacketPtr pkt);
+
+    /**
+     * Send a retry to the peer that previously attempted a
+     * sendTimingReq to this protocol and failed.
+     */
+    void sendRetryReq(TimingRequestProtocol *peer);
+
+    /**
+     * Send a retry to the peer that previously attempted a
+     * sendTimingSnoopResp to this peer and failed.
+     */
+    void sendRetrySnoopResp(TimingRequestProtocol *peer);
+
+    /**
+     * Receive a timing request from the peer.
+     */
+    virtual bool recvTimingReq(PacketPtr pkt) = 0;
+
+    /**
+     * Availability request from the peer.
+     */
+    virtual bool tryTiming(PacketPtr pkt) = 0;
+
+    /**
+     * Receive a timing snoop response from the peer.
+     */
+    virtual bool recvTimingSnoopResp(PacketPtr pkt) = 0;
+
+    /**
+     * Called by the peer if sendTimingResp was called on this
+     * protocol (causing recvTimingResp to be called on the peer)
+     * and was unsuccessful.
+     */
+    virtual void recvRespRetry() = 0;
+};
+
+#endif //__MEM_GEM5_PROTOCOL_TIMING_HH__