port.hh revision 14191 
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 * Authors: Ron Dreslinski
41 *          Andreas Hansson
42 *          William Wang
43 */
44
45/**
46 * @file
47 * Port Object Declaration.
48 */
49
50#ifndef __SIM_PORT_HH__
51#define __SIM_PORT_HH__
52
53#include <string>
54
55#include "base/types.hh"
56
57/**
58 * Ports are used to interface objects to each other.
59 */
60class Port
61{
62
63  private:
64
65    /** Descriptive name (for DPRINTF output) */
66    const std::string portName;
67
68  protected:
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    /**
96     * Virtual destructor due to inheritance.
97     */
98    virtual ~Port();
99
100  public:
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
150static inline std::ostream &
151operator << (std::ostream &os, const Port &port)
152{
153    os << port.name();
154    return os;
155}
156
157#endif //__SIM_PORT_HH__
158