src/mem/protocol/timing.hh

   1 /*
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  12  * modified or unmodified, in source code or in binary form.
  13  *
  14  * Copyright (c) 2002-2005 The Regents of The University of Michigan
  15  * All rights reserved.
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  40
  41 #ifndef __MEM_GEM5_PROTOCOL_TIMING_HH__
  42 #define __MEM_GEM5_PROTOCOL_TIMING_HH__
  43
  44 #include "mem/packet.hh"
  45
  46 class TimingResponseProtocol;
  47
  48 class TimingRequestProtocol
  49 {
  50     friend class TimingResponseProtocol;
  51
  52   protected:
  53     /**
  54      * Attempt to send a timing request to the peer by calling
  55      * its corresponding receive function. If the send does not
  56      * succeed, as indicated by the return value, then the sender must
  57      * wait for a recvReqRetry at which point it can re-issue a
  58      * sendTimingReq.
  59      *
  60      * @param peer Peer to send packet to.
  61      * @param pkt Packet to send.
  62      *
  63      * @return If the send was succesful or not.
  64      */
  65     bool sendReq(TimingResponseProtocol *peer, PacketPtr pkt);
  66
  67     /**
  68      * Check if the peer can handle a timing request.
  69      *
  70      * If the send cannot be handled at the moment, as indicated by
  71      * the return value, then the sender will receive a recvReqRetry
  72      * at which point it can re-issue a sendTimingReq.
  73      *
  74      * @param peer Peer to send packet to.
  75      * @param pkt Packet to send.
  76      *
  77      * @return If the send was succesful or not.
  78      */
  79     bool trySend(TimingResponseProtocol *peer, PacketPtr pkt) const;
  80
  81     /**
  82      * Attempt to send a timing snoop response packet to it's peer
  83      * by calling its corresponding receive function. If the send
  84      * does not succeed, as indicated by the return value, then the
  85      * sender must wait for a recvRetrySnoop at which point it can
  86      * re-issue a sendTimingSnoopResp.
  87      *
  88      * @param pkt Packet to send.
  89      */
  90     bool sendSnoopResp(TimingResponseProtocol *peer, PacketPtr pkt);
  91
  92     /**
  93      * Send a retry to the peer that previously attempted a
  94      * sendTimingResp to this protocol and failed.
  95      */
  96     void sendRetryResp(TimingResponseProtocol *peer);
  97
  98     /**
  99      * Receive a timing response from the peer.
 100      */
 101     virtual bool recvTimingResp(PacketPtr pkt) = 0;
 102
 103     /**
 104      * Receive a timing snoop request from the peer.
 105      */
 106     virtual void recvTimingSnoopReq(PacketPtr pkt) = 0;
 107
 108     /**
 109      * Called by the peer if sendTimingReq was called on this peer (causing
 110      * recvTimingReq to be called on the peer) and was unsuccessful.
 111      */
 112     virtual void recvReqRetry() = 0;
 113
 114     /**
 115      * Called by the peer if sendTimingSnoopResp was called on this
 116      * protocol (causing recvTimingSnoopResp to be called on the peer)
 117      * and was unsuccessful.
 118      */
 119     virtual void recvRetrySnoopResp() = 0;
 120 };
 121
 122 class TimingResponseProtocol
 123 {
 124     friend class TimingRequestProtocol;
 125
 126   protected:
 127     /**
 128      * Attempt to send a timing response to the peer by calling
 129      * its corresponding receive function. If the send does not
 130      * succeed, as indicated by the return value, then the sender must
 131      * wait for a recvRespRetry at which point it can re-issue a
 132      * sendTimingResp.
 133      *
 134      * @param peer Peer to send the packet to.
 135      * @param pkt Packet to send.
 136      *
 137      * @return If the send was succesful or not.
 138     */
 139     bool sendResp(TimingRequestProtocol *peer, PacketPtr pkt);
 140
 141     /**
 142      * Attempt to send a timing snoop request packet to the peer
 143      * by calling its corresponding receive function. Snoop requests
 144      * always succeed and hence no return value is needed.
 145      *
 146      * @param peer Peer to send the packet to.
 147      * @param pkt Packet to send.
 148      */
 149     void sendSnoopReq(TimingRequestProtocol *peer, PacketPtr pkt);
 150
 151     /**
 152      * Send a retry to the peer that previously attempted a
 153      * sendTimingReq to this protocol and failed.
 154      */
 155     void sendRetryReq(TimingRequestProtocol *peer);
 156
 157     /**
 158      * Send a retry to the peer that previously attempted a
 159      * sendTimingSnoopResp to this peer and failed.
 160      */
 161     void sendRetrySnoopResp(TimingRequestProtocol *peer);
 162
 163     /**
 164      * Receive a timing request from the peer.
 165      */
 166     virtual bool recvTimingReq(PacketPtr pkt) = 0;
 167
 168     /**
 169      * Availability request from the peer.
 170      */
 171     virtual bool tryTiming(PacketPtr pkt) = 0;
 172
 173     /**
 174      * Receive a timing snoop response from the peer.
 175      */
 176     virtual bool recvTimingSnoopResp(PacketPtr pkt) = 0;
 177
 178     /**
 179      * Called by the peer if sendTimingResp was called on this
 180      * protocol (causing recvTimingResp to be called on the peer)
 181      * and was unsuccessful.
 182      */
 183     virtual void recvRespRetry() = 0;
 184 };
 185
 186 #endif //__MEM_GEM5_PROTOCOL_TIMING_HH__