src/dev/x86/i8254.cc

   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
  35 Tick
  36 X86ISA::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
  50 Tick
  51 X86ISA::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
  65 X86ISA::I8254 *
  66 I8254Params::create()
  67 {
  68     return new X86ISA::I8254(this);
  69 }