gem5/src/dev/arm/timer_cpulocal.hh

/*
 * Copyright (c) 2010-2011,2018 ARM Limited
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 *
 * The license below extends only to copyright in the software and shall
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 * property including but not limited to intellectual property relating
 * to a hardware implementation of the functionality of the software
 * licensed hereunder.  You may use the software subject to the license
 * terms below provided that you ensure that this notice is replicated
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 * modified or unmodified, in source code or in binary form.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
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 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
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#ifndef __DEV_ARM_LOCALTIMER_HH__
#define __DEV_ARM_LOCALTIMER_HH__

#include <cstdint>
#include <memory>
#include <vector>

#include "base/bitunion.hh"
#include "base/types.hh"
#include "dev/io_device.hh"
#include "params/CpuLocalTimer.hh"
#include "sim/serialize.hh"

/** @file
 * This implements the cpu local timer from the Cortex-A9 MPCore
 * Technical Reference Manual rev r2p2 (ARM DDI 0407F)
 */

namespace gem5
{

class BaseGic;
class ArmInterruptPin;

class CpuLocalTimer : public BasicPioDevice
{
  protected:
    class Timer : public Serializable
    {

      public:
        enum
        {
            TimerLoadReg    	   = 0x00,
            TimerCounterReg 	   = 0x04,
            TimerControlReg 	   = 0x08,
            TimerIntStatusReg      = 0x0C,
            WatchdogLoadReg        = 0x20,
            WatchdogCounterReg     = 0x24,
            WatchdogControlReg     = 0x28,
            WatchdogIntStatusReg   = 0x2C,
            WatchdogResetStatusReg = 0x30,
            WatchdogDisableReg     = 0x34,
            Size                   = 0x38
        };

        BitUnion32(TimerCtrl)
            Bitfield<0>   enable;
            Bitfield<1>   autoReload;
            Bitfield<2>   intEnable;
            Bitfield<7,3> reserved;
            Bitfield<15,8> prescalar;
        EndBitUnion(TimerCtrl)

        BitUnion32(WatchdogCtrl)
            Bitfield<0>   enable;
            Bitfield<1>   autoReload;
            Bitfield<2>   intEnable;
            Bitfield<3>   watchdogMode;
            Bitfield<7,4> reserved;
            Bitfield<15,8> prescalar;
        EndBitUnion(WatchdogCtrl)

      protected:
        std::string _name;

        /** Pointer to parent class */
        CpuLocalTimer *parent;

        /** Interrupt to cause/clear */
        ArmInterruptPin *intTimer;
        ArmInterruptPin *intWatchdog;

        /** Control register as specified above */
        TimerCtrl timerControl;
        WatchdogCtrl watchdogControl;

        /** If timer has caused an interrupt. This is irrespective of
         * interrupt enable */
        bool rawIntTimer;
        bool rawIntWatchdog;
        bool rawResetWatchdog;
        uint32_t watchdogDisableReg;

        /** If an interrupt is currently pending. Logical and of Timer or
          * Watchdog Ctrl.enable and rawIntTimer or rawIntWatchdog */
        bool pendingIntTimer;
        bool pendingIntWatchdog;

        /** Value to load into counters when periodic mode reaches 0 */
        uint32_t timerLoadValue;
        uint32_t watchdogLoadValue;

        /** Called when the counter reaches 0 */
        void timerAtZero();
        EventFunctionWrapper timerZeroEvent;

        void watchdogAtZero();
        EventFunctionWrapper watchdogZeroEvent;
      public:
        /** Restart the counter ticking at val
         * @param val the value to start at */
        void restartTimerCounter(uint32_t val);
        void restartWatchdogCounter(uint32_t val);

        Timer(const std::string &name,
              CpuLocalTimer* _parent,
              ArmInterruptPin* int_timer,
              ArmInterruptPin* int_watchdog);

        std::string name() const { return _name; }

        /** Handle read for a single timer */
        void read(PacketPtr pkt, Addr daddr);

        /** Handle write for a single timer */
        void write(PacketPtr pkt, Addr daddr);

        void serialize(CheckpointOut &cp) const override;
        void unserialize(CheckpointIn &cp) override;

        friend class CpuLocalTimer;
    };

    /** Pointer to the GIC for causing an interrupt */
    BaseGic *gic;

    /** Timers that do the actual work */
    std::vector<std::unique_ptr<Timer>> localTimer;

  public:
    PARAMS(CpuLocalTimer);

    /**
      * The constructor for RealView just registers itself with the MMU.
      * @param p params structure
      */
    CpuLocalTimer(const Params &p);

    /** Inits the local timers */
    void init() override;

    /**
     * Handle a read to the device
     * @param pkt The memory request.
     * @return Returns latency of device read
     */
    Tick read(PacketPtr pkt) override;

    /**
     * Handle a write to the device.
     * @param pkt The memory request.
     * @return Returns latency of device write
     */
    Tick write(PacketPtr pkt) override;

    void serialize(CheckpointOut &cp) const override;
    void unserialize(CheckpointIn &cp) override;
};

} // namespace gem5

#endif // __DEV_ARM_SP804_HH__