src/mem/qport.hh

   1 /*
   2  * Copyright (c) 2012,2015 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 responses. */
  65     RespPacketQueue &respQueue;
  66
  67     void recvRespRetry() { respQueue.retry(); }
  68
  69   public:
  70
  71     /**
  72      * Create a QueuedPort with a given name, owner, and a supplied
  73      * implementation of a packet queue. The external definition of
  74      * the queue enables e.g. the cache to implement a specific queue
  75      * behaviuor in a subclass, and provide the latter to the
  76      * QueuePort constructor.
  77      */
  78     QueuedSlavePort(const std::string& name, MemObject* owner,
  79                     RespPacketQueue &resp_queue, PortID id = InvalidPortID) :
  80         SlavePort(name, owner, id), respQueue(resp_queue)
  81     { }
  82
  83     virtual ~QueuedSlavePort() { }
  84
  85     /**
  86      * Schedule the sending of a timing response.
  87      *
  88      * @param pkt Packet to send
  89      * @param when Absolute time (in ticks) to send packet
  90      */
  91     void schedTimingResp(PacketPtr pkt, Tick when, bool force_order = false)
  92     { respQueue.schedSendTiming(pkt, when, force_order); }
  93
  94     /** Check the list of buffered packets against the supplied
  95      * functional request. */
  96     bool checkFunctional(PacketPtr pkt)
  97     { return respQueue.checkFunctional(pkt); }
  98 };
  99
 100 /**
 101  * The QueuedMasterPort combines two queues, a request queue and a
 102  * snoop response queue, that both share the same port. The flow
 103  * control for requests and snoop responses are completely
 104  * independent, and so each queue manages its own flow control
 105  * (retries).
 106  */
 107 class QueuedMasterPort : public MasterPort
 108 {
 109
 110   protected:
 111
 112     /** Packet queue used to store outgoing requests. */
 113     ReqPacketQueue &reqQueue;
 114
 115     /** Packet queue used to store outgoing snoop responses. */
 116     SnoopRespPacketQueue &snoopRespQueue;
 117
 118     void recvReqRetry() { reqQueue.retry(); }
 119
 120     void recvRetrySnoopResp() { snoopRespQueue.retry(); }
 121
 122   public:
 123
 124     /**
 125      * Create a QueuedPort with a given name, owner, and a supplied
 126      * implementation of two packet queues. The external definition of
 127      * the queues enables e.g. the cache to implement a specific queue
 128      * behaviuor in a subclass, and provide the latter to the
 129      * QueuePort constructor.
 130      */
 131     QueuedMasterPort(const std::string& name, MemObject* owner,
 132                      ReqPacketQueue &req_queue,
 133                      SnoopRespPacketQueue &snoop_resp_queue,
 134                      PortID id = InvalidPortID) :
 135         MasterPort(name, owner, id), reqQueue(req_queue),
 136         snoopRespQueue(snoop_resp_queue)
 137     { }
 138
 139     virtual ~QueuedMasterPort() { }
 140
 141     /**
 142      * Schedule the sending of a timing request.
 143      *
 144      * @param pkt Packet to send
 145      * @param when Absolute time (in ticks) to send packet
 146      */
 147     void schedTimingReq(PacketPtr pkt, Tick when)
 148     { reqQueue.schedSendTiming(pkt, when); }
 149
 150     /**
 151      * Schedule the sending of a timing snoop response.
 152      *
 153      * @param pkt Packet to send
 154      * @param when Absolute time (in ticks) to send packet
 155      */
 156     void schedTimingSnoopResp(PacketPtr pkt, Tick when, bool force_order =
 157                               false)
 158     { snoopRespQueue.schedSendTiming(pkt, when, force_order); }
 159
 160     /** Check the list of buffered packets against the supplied
 161      * functional request. */
 162     bool checkFunctional(PacketPtr pkt)
 163     {
 164         return reqQueue.checkFunctional(pkt) ||
 165             snoopRespQueue.checkFunctional(pkt);
 166     }
 167 };
 168
 169 #endif // __MEM_QPORT_HH__