src/dev/io_device.hh

   1 /*
   2  * Copyright (c) 2012 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  * Copyright (c) 2004-2005 The Regents of The University of Michigan
  15  * All rights reserved.
  16  *
  17  * Redistribution and use in source and binary forms, with or without
  18  * modification, are permitted provided that the following conditions are
  19  * met: redistributions of source code must retain the above copyright
  20  * notice, this list of conditions and the following disclaimer;
  21  * redistributions in binary form must reproduce the above copyright
  22  * notice, this list of conditions and the following disclaimer in the
  23  * documentation and/or other materials provided with the distribution;
  24  * neither the name of the copyright holders nor the names of its
  25  * contributors may be used to endorse or promote products derived from
  26  * this software without specific prior written permission.
  27  *
  28  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  29  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  30  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  31  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  32  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  33  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  34  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  35  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  36  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  37  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  38  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  39  */
  40
  41 #ifndef __DEV_IO_DEVICE_HH__
  42 #define __DEV_IO_DEVICE_HH__
  43
  44 #include "mem/tport.hh"
  45 #include "params/BasicPioDevice.hh"
  46 #include "params/PioDevice.hh"
  47 #include "sim/clocked_object.hh"
  48
  49 class PioDevice;
  50 class System;
  51
  52 /**
  53  * The PioPort class is a programmed i/o port that all devices that are
  54  * sensitive to an address range use. The port takes all the memory
  55  * access types and roles them into one read() and write() call that the device
  56  * must respond to. The device must also provide getAddrRanges() function
  57  * with which it returns the address ranges it is interested in.
  58  */
  59 template <class Device>
  60 class PioPort : public SimpleTimingPort
  61 {
  62   protected:
  63     /** The device that this port serves. */
  64     Device *device;
  65
  66     Tick
  67     recvAtomic(PacketPtr pkt) override
  68     {
  69         // Technically the packet only reaches us after the header delay,
  70         // and typically we also need to deserialise any payload.
  71         Tick receive_delay = pkt->headerDelay + pkt->payloadDelay;
  72         pkt->headerDelay = pkt->payloadDelay = 0;
  73
  74         const Tick delay =
  75             pkt->isRead() ? device->read(pkt) : device->write(pkt);
  76         assert(pkt->isResponse() || pkt->isError());
  77         return delay + receive_delay;
  78     }
  79
  80     AddrRangeList
  81     getAddrRanges() const override
  82     {
  83         return device->getAddrRanges();
  84     }
  85
  86   public:
  87     PioPort(Device *dev) :
  88         SimpleTimingPort(dev->name() + ".pio", dev), device(dev)
  89     {}
  90 };
  91
  92 /**
  93  * This device is the base class which all devices senstive to an address range
  94  * inherit from. There are three pure virtual functions which all devices must
  95  * implement getAddrRanges(), read(), and write(). The magic do choose which
  96  * mode we are in, etc is handled by the PioPort so the device doesn't have to
  97  * bother.
  98  */
  99 class PioDevice : public ClockedObject
 100 {
 101   protected:
 102     System *sys;
 103
 104     /** The pioPort that handles the requests for us and provides us requests
 105      * that it sees. */
 106     PioPort<PioDevice> pioPort;
 107
 108     /**
 109      * Every PIO device is obliged to provide an implementation that
 110      * returns the address ranges the device responds to.
 111      *
 112      * @return a list of non-overlapping address ranges
 113      */
 114     virtual AddrRangeList getAddrRanges() const = 0;
 115
 116     /** Pure virtual function that the device must implement. Called
 117      * when a read command is recieved by the port.
 118      * @param pkt Packet describing this request
 119      * @return number of ticks it took to complete
 120      */
 121     virtual Tick read(PacketPtr pkt) = 0;
 122
 123     /** Pure virtual function that the device must implement. Called when a
 124      * write command is recieved by the port.
 125      * @param pkt Packet describing this request
 126      * @return number of ticks it took to complete
 127      */
 128     virtual Tick write(PacketPtr pkt) = 0;
 129
 130   public:
 131     typedef PioDeviceParams Params;
 132     PioDevice(const Params *p);
 133     virtual ~PioDevice();
 134
 135     const Params *
 136     params() const
 137     {
 138         return dynamic_cast<const Params *>(_params);
 139     }
 140
 141     void init() override;
 142
 143     Port &getPort(const std::string &if_name,
 144             PortID idx=InvalidPortID) override;
 145
 146     friend class PioPort<PioDevice>;
 147
 148 };
 149
 150 class BasicPioDevice : public PioDevice
 151 {
 152   protected:
 153     /** Address that the device listens to. */
 154     Addr pioAddr;
 155
 156     /** Size that the device's address range. */
 157     Addr pioSize;
 158
 159     /** Delay that the device experinces on an access. */
 160     Tick pioDelay;
 161
 162   public:
 163     typedef BasicPioDeviceParams Params;
 164     BasicPioDevice(const Params *p, Addr size);
 165
 166     const Params *
 167     params() const
 168     {
 169         return dynamic_cast<const Params *>(_params);
 170     }
 171
 172     /**
 173      * Determine the address ranges that this device responds to.
 174      *
 175      * @return a list of non-overlapping address ranges
 176      */
 177     AddrRangeList getAddrRanges() const override;
 178 };
 179
 180 #endif // __DEV_IO_DEVICE_HH__