clock_domain.hh

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/*
 * Copyright (c) 2013-2014, 2019 ARM Limited
 * Copyright (c) 2013 Cornell University
 * All rights reserved
 *
 * The license below extends only to copyright in the software and shall
 * not be construed as granting a license to any other intellectual
 * 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
 * unmodified and in its entirety in all distributions of the software,
 * 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
 * documentation and/or other materials provided with the distribution;
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Authors: Vasileios Spiliopoulos
 *          Akash Bagdia
 *          Christopher Torng
 *          Stephan Diestelhorst
 */

#ifndef __SIM_CLOCK_DOMAIN_HH__
#define __SIM_CLOCK_DOMAIN_HH__

#include <algorithm>

#include "base/statistics.hh"
#include "params/ClockDomain.hh"
#include "params/DerivedClockDomain.hh"
#include "params/SrcClockDomain.hh"
#include "sim/sim_object.hh"

class DerivedClockDomain;
class VoltageDomain;
class Clocked;

class ClockDomain : public SimObject
{
  protected:

    Tick _clockPeriod;

    VoltageDomain *_voltageDomain;

    std::vector<DerivedClockDomain*> children;

    std::vector<Clocked *> members;

  public:

    typedef ClockDomainParams Params;
    ClockDomain(const Params *p, VoltageDomain *voltage_domain);

    Tick clockPeriod() const { return _clockPeriod; }

    void registerWithClockDomain(Clocked *c)
    {
        assert(c != NULL);
        assert(std::find(members.begin(), members.end(), c) == members.end());
        members.push_back(c);
    }

    inline VoltageDomain *voltageDomain() const { return _voltageDomain; }


    double voltage() const;

    void addDerivedDomain(DerivedClockDomain *clock_domain)
    { children.push_back(clock_domain); }

  private:
    struct ClockDomainStats : public Stats::Group
    {
        ClockDomainStats(ClockDomain &cd);

        Stats::Value clock;
    } stats;
};

class SrcClockDomain : public ClockDomain
{

  public:

    typedef SrcClockDomainParams Params;
    SrcClockDomain(const Params *p);

    void clockPeriod(Tick clock_period);

    // Explicitly import the otherwise hidden clockPeriod
    using ClockDomain::clockPeriod;

    typedef int32_t DomainID;
    static const DomainID emptyDomainID = -1;

    uint32_t domainID() const { return _domainID; }

    typedef uint32_t PerfLevel;
    bool validPerfLevel(PerfLevel perf_level) const {
        return perf_level < numPerfLevels();
    }

    void perfLevel(PerfLevel perf_level);

    PerfLevel perfLevel() const { return _perfLevel; }

    PerfLevel numPerfLevels() const {return freqOpPoints.size();}

    Tick clkPeriodAtPerfLevel() const { return freqOpPoints[perfLevel()]; }

    Tick clkPeriodAtPerfLevel(PerfLevel perf_level) const
    {
        assert(validPerfLevel(perf_level));
        return freqOpPoints[perf_level];
    }

    void startup() override;

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

  private:
    void signalPerfLevelUpdate();

    const std::vector<Tick> freqOpPoints;

    const uint32_t _domainID;

    PerfLevel _perfLevel;
};

class DerivedClockDomain: public ClockDomain
{

  public:

    typedef DerivedClockDomainParams Params;
    DerivedClockDomain(const Params *p);

    void updateClockPeriod();

  private:

    ClockDomain &parent;

    const uint64_t clockDivider;
};

#endif