qport.hh revision 8914:8c3bd7bea667 
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 */
59class QueuedPort : public Port
60{
61
62  protected:
63
64    /** Packet queue used to store outgoing requests and responses. */
65    PacketQueue &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    virtual void recvRangeChange() { }
72
73  public:
74
75    /**
76     * Create a QueuedPort with a given name, owner, and a supplied
77     * implementation of a packet queue. The external definition of
78     * the queue enables e.g. the cache to implement a specific queue
79     * behaviuor in a subclass, and provide the latter to the
80     * QueuePort constructor.
81     */
82    QueuedPort(const std::string& name, MemObject* owner, PacketQueue &queue) :
83        Port(name, owner), queue(queue)
84    { }
85
86    virtual ~QueuedPort() { }
87
88    /** Check the list of buffered packets against the supplied
89     * functional request. */
90    bool checkFunctional(PacketPtr pkt) { return queue.checkFunctional(pkt); }
91
92    /**
93     * Hook for draining the queued port.
94     *
95     * @param de an event which is used to signal back to the caller
96     * @returns a number indicating how many times process will be called
97     */
98    unsigned int drain(Event *de) { return queue.drain(de); }
99};
100
101#endif // __MEM_QPORT_HH__
102