src/arch/arm/isa_device.hh

   1 /*
   2  * Copyright (c) 2014, 2017 ARM Limited
   3  * All rights reserved
   4  *
   5  * The license below extends only to copyright in the software and shall
   6  * not be construed as granting a license to any other intellectual
   7  * property including but not limited to intellectual property relating
   8  * to a hardware implementation of the functionality of the software
   9  * licensed hereunder.  You may use the software subject to the license
  10  * terms below provided that you ensure that this notice is replicated
  11  * unmodified and in its entirety in all distributions of the software,
  12  * modified or unmodified, in source code or in binary form.
  13  *
  14  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions are
  16  * met: redistributions of source code must retain the above copyright
  17  * notice, this list of conditions and the following disclaimer;
  18  * redistributions in binary form must reproduce the above copyright
  19  * notice, this list of conditions and the following disclaimer in the
  20  * documentation and/or other materials provided with the distribution;
  21  * neither the name of the copyright holders nor the names of its
  22  * contributors may be used to endorse or promote products derived from
  23  * this software without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  26  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  27  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  28  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  29  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  30  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  31  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  35  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  *
  37  * Authors: Andreas Sandberg
  38  */
  39
  40 #ifndef __ARCH_ARM_ISA_DEVICE_HH__
  41 #define __ARCH_ARM_ISA_DEVICE_HH__
  42
  43 #include "arch/arm/registers.hh"
  44 #include "base/compiler.hh"
  45
  46 class ThreadContext;
  47
  48 namespace ArmISA
  49 {
  50
  51 class ISA;
  52
  53 /**
  54  * Base class for devices that use the MiscReg interfaces.
  55  *
  56  * This class provides a well-defined interface that the ArmISA class
  57  * can use when forwarding MiscReg accesses to a device model (e.g., a
  58  * PMU or GIC).
  59  */
  60 class BaseISADevice
  61 {
  62   public:
  63     BaseISADevice();
  64     virtual ~BaseISADevice() {}
  65
  66     virtual void setISA(ISA *isa);
  67     virtual void setThreadContext(ThreadContext *tc) {}
  68
  69     /**
  70      * Write to a system register belonging to this device.
  71      *
  72      * @param misc_reg Register number (see miscregs.hh)
  73      * @param val Value to store
  74      */
  75     virtual void setMiscReg(int misc_reg, RegVal val) = 0;
  76
  77     /**
  78      * Read a system register belonging to this device.
  79      *
  80      * @param misc_reg Register number (see miscregs.hh)
  81      * @return Register value.
  82      */
  83     virtual RegVal readMiscReg(int misc_reg) = 0;
  84
  85   protected:
  86     ISA *isa;
  87 };
  88
  89 /**
  90  * Dummy device that prints a warning when it is accessed.
  91  *
  92  * This device can be used as a placeholder when a real device model
  93  * is not present. For example, the ISA code uses it to avoid having
  94  * to check for a PMU in the register access code.
  95  */
  96 class DummyISADevice : public BaseISADevice
  97 {
  98   public:
  99     DummyISADevice()
 100         : BaseISADevice() {}
 101     ~DummyISADevice() {}
 102
 103     void setMiscReg(int misc_reg, RegVal val) override;
 104     RegVal readMiscReg(int misc_reg) override;
 105 };
 106
 107 }
 108
 109 #endif // __ARCH_ARM_ISA_DEVICE_HH__