i8254.cc revision 5636 
1/*
2 * Copyright (c) 2008 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: Gabe Black
29 */
30
31#include "dev/x86/i8254.hh"
32#include "mem/packet.hh"
33#include "mem/packet_access.hh"
34
35Tick
36X86ISA::I8254::read(PacketPtr pkt)
37{
38    assert(pkt->getSize() == 1);
39    Addr offset = pkt->getAddr() - pioAddr;
40    if (offset < 3) {
41        pkt->set(pit.readCounter(offset));
42    } else if (offset == 3) {
43        pkt->set(uint8_t(-1));
44    } else {
45        panic("Read from undefined i8254 register.\n");
46    }
47    return latency;
48}
49
50Tick
51X86ISA::I8254::write(PacketPtr pkt)
52{
53    assert(pkt->getSize() == 1);
54    Addr offset = pkt->getAddr() - pioAddr;
55    if (offset < 3) {
56        pit.writeCounter(offset, pkt->get<uint8_t>());
57    } else if (offset == 3) {
58        pit.writeControl(pkt->get<uint8_t>());
59    } else {
60        panic("Write to undefined i8254 register.\n");
61    }
62    return latency;
63}
64
65X86ISA::I8254 *
66I8254Params::create()
67{
68    return new X86ISA::I8254(this);
69}
70