src/dev/isa_fake.hh

   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 <string>
  37
  38 #include "dev/io_device.hh"
  39 #include "mem/packet.hh"
  40 #include "params/IsaFake.hh"
  41
  42 /**
  43  * IsaFake is a device that returns, BadAddr, 1 or 0 on all reads and
  44  *  rites. It is meant to be placed at an address range
  45  * so that an mcheck doesn't occur when an os probes a piece of hw
  46  * that doesn't exist (e.g. UARTs1-3), or catch requests in the memory system
  47  * that have no responders..
  48  */
  49 class IsaFake : public BasicPioDevice
  50 {
  51   protected:
  52     uint8_t retData8;
  53     uint16_t retData16;
  54     uint32_t retData32;
  55     uint64_t retData64;
  56
  57   public:
  58     typedef IsaFakeParams Params;
  59     const Params *
  60     params() const
  61     {
  62         return dynamic_cast<const Params *>(_params);
  63     }
  64     /**
  65       * The constructor for Isa Fake just registers itself with the MMU.
  66       * @param p params structure
  67       */
  68     IsaFake(Params *p);
  69
  70     /**
  71      * This read always returns -1.
  72      * @param pkt The memory request.
  73      * @param data Where to put the data.
  74      */
  75     virtual Tick read(PacketPtr pkt);
  76
  77     /**
  78      * All writes are simply ignored.
  79      * @param pkt The memory request.
  80      * @param data the data to not write.
  81      */
  82     virtual Tick write(PacketPtr pkt);
  83 };
  84
  85 #endif // __ISA_FAKE_HH__