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
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   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
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  23  * this software without specific prior written permission.
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  35  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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  37
  38 #ifndef __MEM_QPORT_HH__
  39 #define __MEM_QPORT_HH__
  40
  41 /**
  42  * @file
  43  * Declaration of the queued port.
  44  */
  45
  46 #include "mem/packet_queue.hh"
  47 #include "mem/port.hh"
  48 #include "sim/sim_object.hh"
  49
  50 /**
  51  * A queued port is a port that has an infinite queue for outgoing
  52  * packets and thus decouples the module that wants to send
  53  * request/responses from the flow control (retry mechanism) of the
  54  * port. A queued port can be used by both a requestor and a responder. The
  55  * queue is a parameter to allow tailoring of the queue implementation
  56  * (used in the cache).
  57  */
  58 class QueuedResponsePort : public ResponsePort
  59 {
  60
  61   protected:
  62
  63     /** Packet queue used to store outgoing responses. */
  64     RespPacketQueue &respQueue;
  65
  66     void recvRespRetry() { respQueue.retry(); }
  67
  68   public:
  69
  70     /**
  71      * Create a QueuedPort with a given name, owner, and a supplied
  72      * implementation of a packet queue. The external definition of
  73      * the queue enables e.g. the cache to implement a specific queue
  74      * behaviuor in a subclass, and provide the latter to the
  75      * QueuePort constructor.
  76      */
  77     QueuedResponsePort(const std::string& name, SimObject* owner,
  78                     RespPacketQueue &resp_queue, PortID id = InvalidPortID) :
  79         ResponsePort(name, owner, id), respQueue(resp_queue)
  80     { }
  81
  82     virtual ~QueuedResponsePort() { }
  83
  84     /**
  85      * Schedule the sending of a timing response.
  86      *
  87      * @param pkt Packet to send
  88      * @param when Absolute time (in ticks) to send packet
  89      */
  90     void schedTimingResp(PacketPtr pkt, Tick when)
  91     { respQueue.schedSendTiming(pkt, when); }
  92
  93     /** Check the list of buffered packets against the supplied
  94      * functional request. */
  95     bool trySatisfyFunctional(PacketPtr pkt)
  96     { return respQueue.trySatisfyFunctional(pkt); }
  97 };
  98
  99 /**
 100  * The QueuedRequestPort combines two queues, a request queue and a
 101  * snoop response queue, that both share the same port. The flow
 102  * control for requests and snoop responses are completely
 103  * independent, and so each queue manages its own flow control
 104  * (retries).
 105  */
 106 class QueuedRequestPort : public RequestPort
 107 {
 108
 109   protected:
 110
 111     /** Packet queue used to store outgoing requests. */
 112     ReqPacketQueue &reqQueue;
 113
 114     /** Packet queue used to store outgoing snoop responses. */
 115     SnoopRespPacketQueue &snoopRespQueue;
 116
 117     void recvReqRetry() { reqQueue.retry(); }
 118
 119     void recvRetrySnoopResp() { snoopRespQueue.retry(); }
 120
 121   public:
 122
 123     /**
 124      * Create a QueuedPort with a given name, owner, and a supplied
 125      * implementation of two packet queues. The external definition of
 126      * the queues enables e.g. the cache to implement a specific queue
 127      * behaviuor in a subclass, and provide the latter to the
 128      * QueuePort constructor.
 129      */
 130     QueuedRequestPort(const std::string& name, SimObject* owner,
 131                      ReqPacketQueue &req_queue,
 132                      SnoopRespPacketQueue &snoop_resp_queue,
 133                      PortID id = InvalidPortID) :
 134         RequestPort(name, owner, id), reqQueue(req_queue),
 135         snoopRespQueue(snoop_resp_queue)
 136     { }
 137
 138     virtual ~QueuedRequestPort() { }
 139
 140     /**
 141      * Schedule the sending of a timing request.
 142      *
 143      * @param pkt Packet to send
 144      * @param when Absolute time (in ticks) to send packet
 145      */
 146     void schedTimingReq(PacketPtr pkt, Tick when)
 147     { reqQueue.schedSendTiming(pkt, when); }
 148
 149     /**
 150      * Schedule the sending of a timing snoop response.
 151      *
 152      * @param pkt Packet to send
 153      * @param when Absolute time (in ticks) to send packet
 154      */
 155     void schedTimingSnoopResp(PacketPtr pkt, Tick when)
 156     { snoopRespQueue.schedSendTiming(pkt, when); }
 157
 158     /** Check the list of buffered packets against the supplied
 159      * functional request. */
 160     bool trySatisfyFunctional(PacketPtr pkt)
 161     {
 162         return reqQueue.trySatisfyFunctional(pkt) ||
 163             snoopRespQueue.trySatisfyFunctional(pkt);
 164     }
 165 };
 166
 167 #endif // __MEM_QPORT_HH__