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  * 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 "dev/io_device.hh"
  41 // #include "dev/alpha/tsunami.hh"
  42 #include "mem/packet.hh"
  43 #include "params/IsaFake.hh"
  44
  45 /**
  46  * IsaFake is a device that returns, BadAddr, 1 or 0 on all reads and
  47  *  rites. It is meant to be placed at an address range
  48  * so that an mcheck doesn't occur when an os probes a piece of hw
  49  * that doesn't exist (e.g. UARTs1-3), or catch requests in the memory system
  50  * that have no responders..
  51  */
  52 class IsaFake : public BasicPioDevice
  53 {
  54   protected:
  55     uint8_t retData8;
  56     uint16_t retData16;
  57     uint32_t retData32;
  58     uint64_t retData64;
  59
  60   public:
  61     typedef IsaFakeParams Params;
  62     const Params *
  63     params() const
  64     {
  65         return dynamic_cast<const Params *>(_params);
  66     }
  67     /**
  68       * The constructor for Isa Fake just registers itself with the MMU.
  69       * @param p params structure
  70       */
  71     IsaFake(Params *p);
  72
  73     /**
  74      * This read always returns -1.
  75      * @param pkt The memory request.
  76      * @param data Where to put the data.
  77      */
  78     virtual Tick read(PacketPtr pkt);
  79
  80     /**
  81      * All writes are simply ignored.
  82      * @param pkt The memory request.
  83      * @param data the data to not write.
  84      */
  85     virtual Tick write(PacketPtr pkt);
  86 };
  87
  88 #endif // __ISA_FAKE_HH__