src/sim/port.hh

   1 /*
   2  * Copyright (c) 2011-2012,2015,2017 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  * Copyright (c) 2002-2005 The Regents of The University of Michigan
  15  * All rights reserved.
  16  *
  17  * Redistribution and use in source and binary forms, with or without
  18  * modification, are permitted provided that the following conditions are
  19  * met: redistributions of source code must retain the above copyright
  20  * notice, this list of conditions and the following disclaimer;
  21  * redistributions in binary form must reproduce the above copyright
  22  * notice, this list of conditions and the following disclaimer in the
  23  * documentation and/or other materials provided with the distribution;
  24  * neither the name of the copyright holders nor the names of its
  25  * contributors may be used to endorse or promote products derived from
  26  * this software without specific prior written permission.
  27  *
  28  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  29  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  30  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  31  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  32  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  33  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  34  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  35  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  36  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  37  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  38  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  39  */
  40
  41 /**
  42  * @file
  43  * Port Object Declaration.
  44  */
  45
  46 #ifndef __SIM_PORT_HH__
  47 #define __SIM_PORT_HH__
  48
  49 #include <string>
  50
  51 #include "base/types.hh"
  52
  53 /**
  54  * Ports are used to interface objects to each other.
  55  */
  56 class Port
  57 {
  58
  59   private:
  60
  61     /** Descriptive name (for DPRINTF output) */
  62     const std::string portName;
  63
  64   protected:
  65
  66     class UnboundPortException {};
  67
  68     [[noreturn]] void reportUnbound() const;
  69
  70     /**
  71      * A numeric identifier to distinguish ports in a vector, and set
  72      * to InvalidPortID in case this port is not part of a vector.
  73      */
  74     const PortID id;
  75
  76     /**
  77      * A pointer to this port's peer.
  78      */
  79     Port *_peer;
  80
  81
  82     /**
  83      * Whether this port is currently connected to a peer port.
  84      */
  85     bool _connected;
  86
  87     /**
  88      * Abstract base class for ports
  89      *
  90      * @param _name Port name including the owners name
  91      * @param _id A port identifier for vector ports
  92      */
  93     Port(const std::string& _name, PortID _id);
  94
  95   public:
  96
  97     /**
  98      * Virtual destructor due to inheritance.
  99      */
 100     virtual ~Port();
 101
 102     /** Return a reference to this port's peer. */
 103     Port &getPeer() { return *_peer; }
 104
 105     /** Return port name (for DPRINTF). */
 106     const std::string name() const { return portName; }
 107
 108     /** Get the port id. */
 109     PortID getId() const { return id; }
 110
 111     /** Attach to a peer port. */
 112     virtual void
 113     bind(Port &peer)
 114     {
 115         _peer = &peer;
 116         _connected = true;
 117     }
 118
 119     /** Dettach from a peer port. */
 120     virtual void
 121     unbind()
 122     {
 123         _peer = nullptr;
 124         _connected = false;
 125     }
 126
 127     /** Is this port currently connected to a peer? */
 128     bool isConnected() const { return _connected; }
 129
 130     /** A utility function to make it easier to swap out ports. */
 131     void
 132     takeOverFrom(Port *old)
 133     {
 134         assert(old);
 135         assert(old->isConnected());
 136         assert(!isConnected());
 137         Port &peer = old->getPeer();
 138         assert(peer.isConnected());
 139
 140         // Disconnect the original binding.
 141         old->unbind();
 142         peer.unbind();
 143
 144         // Connect the new binding.
 145         peer.bind(*this);
 146         bind(peer);
 147     }
 148 };
 149
 150 static inline std::ostream &
 151 operator << (std::ostream &os, const Port &port)
 152 {
 153     os << port.name();
 154     return os;
 155 }
 156
 157 #endif //__SIM_PORT_HH__