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 "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  */
  46 class IsaFake : public BasicPioDevice
  47 {
  48   public:
  49     struct Params : public BasicPioDevice::Params
  50     {
  51         Addr pio_size;
  52     };
  53   protected:
  54     const Params *params() const { return (const Params*)_params; }
  55
  56   public:
  57     /**
  58       * The constructor for Tsunmami Fake just registers itself with the MMU.
  59       * @param p params structure
  60       */
  61     IsaFake(Params *p);
  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 Tick read(Packet *pkt);
  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 Tick write(Packet *pkt);
  76 };
  77
  78 #endif // __TSUNAMI_FAKE_HH__