/*
 * Copyright (c) 2008 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: Gabe Black
 */

#ifndef __MEM_MPORT_HH__
#define __MEM_MPORT_HH__

#include "mem/tport.hh"

/*
 * This file defines a port class which is used for sending and receiving
 * messages. These messages are atomic units which don't interact and
 * should be smaller than a cache block. This class is based on 
 * the underpinnings of SimpleTimingPort, but it tweaks some of the external
 * functions.
 */

class MessagePort : public SimpleTimingPort
{
  public:
    MessagePort(std::string pname, MemObject *_owner = NULL) :
        SimpleTimingPort(pname, _owner)
    {}

    virtual ~MessagePort()
    {}

    void
    recvFunctional(PacketPtr pkt)
    {
        recvAtomic(pkt);
    }

    Tick recvAtomic(PacketPtr pkt);

    virtual Tick recvMessage(PacketPtr pkt) = 0;

    // Accept and ignore responses.
    virtual Tick recvResponse(PacketPtr pkt)
    {
        return 0;
    }

    // Since by default we're assuming everything we send is accepted, panic.
    virtual Tick recvNack(PacketPtr pkt)
    {
        panic("Unhandled message nack.\n");
    }

    void sendMessageTiming(PacketPtr pkt, Tick latency);
    Tick sendMessageAtomic(PacketPtr pkt);
};

#endif
