isa_fake.hh revision 5034 
1/*
2 * Copyright (c) 2004-2005 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Authors: Ali Saidi
29 */
30
31/** @file
32 * Declaration of a fake device.
33 */
34
35#ifndef __ISA_FAKE_HH__
36#define __ISA_FAKE_HH__
37
38#include <string>
39
40#include "base/range.hh"
41#include "dev/io_device.hh"
42// #include "dev/alpha/tsunami.hh"
43#include "params/IsaFake.hh"
44#include "mem/packet.hh"
45
46/**
47 * IsaFake is a device that returns, BadAddr, 1 or 0 on all reads and
48 *  rites. It is meant to be placed at an address range
49 * so that an mcheck doesn't occur when an os probes a piece of hw
50 * that doesn't exist (e.g. UARTs1-3), or catch requests in the memory system
51 * that have no responders..
52 */
53class IsaFake : public BasicPioDevice
54{
55  protected:
56    uint8_t retData8;
57    uint16_t retData16;
58    uint32_t retData32;
59    uint64_t retData64;
60
61  public:
62    typedef IsaFakeParams Params;
63    const Params *
64    params() const
65    {
66        return dynamic_cast<const Params *>(_params);
67    }
68    /**
69      * The constructor for Tsunmami Fake just registers itself with the MMU.
70      * @param p params structure
71      */
72    IsaFake(Params *p);
73
74    /**
75     * This read always returns -1.
76     * @param pkt The memory request.
77     * @param data Where to put the data.
78     */
79    virtual Tick read(PacketPtr pkt);
80
81    /**
82     * All writes are simply ignored.
83     * @param pkt The memory request.
84     * @param data the data to not write.
85     */
86    virtual Tick write(PacketPtr pkt);
87};
88
89#endif // __ISA_FAKE_HH__
90