atomic.hh revision 14185 
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#ifndef __MEM_GEM5_PROTOCOL_ATOMIC_HH__
46#define __MEM_GEM5_PROTOCOL_ATOMIC_HH__
47
48#include "mem/backdoor.hh"
49#include "mem/packet.hh"
50
51class AtomicResponseProtocol;
52
53class AtomicRequestProtocol
54{
55    friend class AtomicResponseProtocol;
56
57  protected:
58    /**
59     * Send an atomic request packet, where the data is moved and the
60     * state is updated in zero time, without interleaving with other
61     * memory accesses.
62     *
63     * @param peer Peer to send packet to.
64     * @param pkt Packet to send.
65     *
66     * @return Estimated latency of access.
67     */
68    Tick send(AtomicResponseProtocol *peer, PacketPtr pkt);
69
70    /**
71     * Send an atomic request packet like above, but also request a backdoor
72     * to the data being accessed.
73     *
74     * @param peer Peer to send packet to.
75     * @param pkt Packet to send.
76     * @param backdoor Can be set to a back door pointer by the target to let
77     *        caller have direct access to the requested data.
78     *
79     * @return Estimated latency of access.
80     */
81    Tick sendBackdoor(AtomicResponseProtocol *peer, PacketPtr pkt,
82                      MemBackdoorPtr &backdoor);
83
84    /**
85     * Receive an atomic snoop request packet from our peer.
86     */
87    virtual Tick recvAtomicSnoop(PacketPtr pkt) = 0;
88};
89
90class AtomicResponseProtocol
91{
92    friend class AtomicRequestProtocol;
93
94  protected:
95    /**
96     * Send an atomic snoop request packet, where the data is moved
97     * and the state is updated in zero time, without interleaving
98     * with other memory accesses.
99     *
100     * @param peer Peer to send packet to.
101     * @param pkt Snoop packet to send.
102     *
103     * @return Estimated latency of access.
104     */
105    Tick sendSnoop(AtomicRequestProtocol *peer, PacketPtr pkt);
106
107    /**
108     * Receive an atomic request packet from the peer.
109     */
110    virtual Tick recvAtomic(PacketPtr pkt) = 0;
111
112    /**
113     * Receive an atomic request packet from the peer, and optionally
114     * provide a backdoor to the data being accessed.
115     */
116    virtual Tick recvAtomicBackdoor(
117            PacketPtr pkt, MemBackdoorPtr &backdoor) = 0;
118};
119
120#endif //__MEM_GEM5_PROTOCOL_ATOMIC_HH__
121