src/mem/qport.hh

   1 /*
   2  * Copyright (c) 2012 ARM Limited
   3  * All rights reserved.
   4  *
   5  * The license below extends only to copyright in the software and shall
   6  * not be construed as granting a license to any other intellectual
   7  * property including but not limited to intellectual property relating
   8  * to a hardware implementation of the functionality of the software
   9  * licensed hereunder.  You may use the software subject to the license
  10  * terms below provided that you ensure that this notice is replicated
  11  * unmodified and in its entirety in all distributions of the software,
  12  * modified or unmodified, in source code or in binary form.
  13  *
  14  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions are
  16  * met: redistributions of source code must retain the above copyright
  17  * notice, this list of conditions and the following disclaimer;
  18  * redistributions in binary form must reproduce the above copyright
  19  * notice, this list of conditions and the following disclaimer in the
  20  * documentation and/or other materials provided with the distribution;
  21  * neither the name of the copyright holders nor the names of its
  22  * contributors may be used to endorse or promote products derived from
  23  * this software without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  26  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  27  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  28  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  29  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  30  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  31  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  35  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  *
  37  * Authors: Andreas Hansson
  38  */
  39
  40 #ifndef __MEM_QPORT_HH__
  41 #define __MEM_QPORT_HH__
  42
  43 /**
  44  * @file
  45  * Declaration of the queued port.
  46  */
  47
  48 #include "mem/packet_queue.hh"
  49 #include "mem/port.hh"
  50
  51 /**
  52  * A queued port is a port that has an infinite queue for outgoing
  53  * packets and thus decouples the module that wants to send
  54  * request/responses from the flow control (retry mechanism) of the
  55  * port. A queued port can be used by both a master and a slave. The
  56  * queue is a parameter to allow tailoring of the queue implementation
  57  * (used in the cache).
  58  */
  59 class QueuedSlavePort : public SlavePort
  60 {
  61
  62   protected:
  63
  64     /** Packet queue used to store outgoing requests and responses. */
  65     SlavePacketQueue &queue;
  66
  67      /** This function is notification that the device should attempt to send a
  68       * packet again. */
  69     virtual void recvRetry() { queue.retry(); }
  70
  71   public:
  72
  73     /**
  74      * Create a QueuedPort with a given name, owner, and a supplied
  75      * implementation of a packet queue. The external definition of
  76      * the queue enables e.g. the cache to implement a specific queue
  77      * behaviuor in a subclass, and provide the latter to the
  78      * QueuePort constructor.
  79      */
  80     QueuedSlavePort(const std::string& name, MemObject* owner,
  81                     SlavePacketQueue &queue) :
  82         SlavePort(name, owner), queue(queue)
  83     { }
  84
  85     virtual ~QueuedSlavePort() { }
  86
  87     /** Check the list of buffered packets against the supplied
  88      * functional request. */
  89     bool checkFunctional(PacketPtr pkt) { return queue.checkFunctional(pkt); }
  90
  91     /**
  92      * Hook for draining the queued port.
  93      *
  94      * @param de an event which is used to signal back to the caller
  95      * @returns a number indicating how many times process will be called
  96      */
  97     unsigned int drain(Event *de) { return queue.drain(de); }
  98 };
  99
 100 class QueuedMasterPort : public MasterPort
 101 {
 102
 103   protected:
 104
 105     /** Packet queue used to store outgoing requests and responses. */
 106     MasterPacketQueue &queue;
 107
 108      /** This function is notification that the device should attempt to send a
 109       * packet again. */
 110     virtual void recvRetry() { queue.retry(); }
 111
 112   public:
 113
 114     /**
 115      * Create a QueuedPort with a given name, owner, and a supplied
 116      * implementation of a packet queue. The external definition of
 117      * the queue enables e.g. the cache to implement a specific queue
 118      * behaviuor in a subclass, and provide the latter to the
 119      * QueuePort constructor.
 120      */
 121     QueuedMasterPort(const std::string& name, MemObject* owner,
 122                      MasterPacketQueue &queue) :
 123         MasterPort(name, owner), queue(queue)
 124     { }
 125
 126     virtual ~QueuedMasterPort() { }
 127
 128     /** Check the list of buffered packets against the supplied
 129      * functional request. */
 130     bool checkFunctional(PacketPtr pkt) { return queue.checkFunctional(pkt); }
 131
 132     /**
 133      * Hook for draining the queued port.
 134      *
 135      * @param de an event which is used to signal back to the caller
 136      * @returns a number indicating how many times process will be called
 137      */
 138     unsigned int drain(Event *de) { return queue.drain(de); }
 139 };
 140
 141 #endif // __MEM_QPORT_HH__