isa_fake.hh revision 1817 
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
29/** @file
30 * Declaration of a fake device.
31 */
32
33#ifndef __ISA_FAKE_HH__
34#define __ISA_FAKE_HH__
35
36#include "dev/tsunami.hh"
37#include "base/range.hh"
38#include "dev/io_device.hh"
39
40/**
41 * IsaFake is a device that returns -1 on all reads and
42 * accepts all writes. It is meant to be placed at an address range
43 * so that an mcheck doesn't occur when an os probes a piece of hw
44 * that doesn't exist (e.g. UARTs1-3).
45 */
46class IsaFake : public PioDevice
47{
48  private:
49    /** The address in memory that we respond to */
50    Addr addr;
51
52  public:
53    /**
54      * The constructor for Tsunmami Fake just registers itself with the MMU.
55      * @param name name of this device.
56      * @param a address to respond to.
57      * @param mmu the mmu we register with.
58      * @param size number of addresses to respond to
59      */
60    IsaFake(const std::string &name, Addr a, MemoryController *mmu,
61                HierParams *hier, Bus *bus, Addr size = 0x8);
62
63    /**
64     * This read always returns -1.
65     * @param req The memory request.
66     * @param data Where to put the data.
67     */
68    virtual Fault read(MemReqPtr &req, uint8_t *data);
69
70    /**
71     * All writes are simply ignored.
72     * @param req The memory request.
73     * @param data the data to not write.
74     */
75    virtual Fault write(MemReqPtr &req, const uint8_t *data);
76
77    /**
78     * Return how long this access will take.
79     * @param req the memory request to calcuate
80     * @return Tick when the request is done
81     */
82    Tick cacheAccess(MemReqPtr &req);
83};
84
85#endif // __ISA_FAKE_HH__
86