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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
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* 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,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* @file
* ClockDomain declarations.
*/
#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"
namespace gem5
{
/**
* Forward declaration
*/
class DerivedClockDomain;
class VoltageDomain;
class Clocked;
/**
* The ClockDomain provides clock to group of clocked objects bundled
* under the same clock domain. The clock domains, in turn, are
* grouped into voltage domains. The clock domains provide support for
* a hierarchial structure with source and derived domains.
*/
class ClockDomain : public SimObject
{
protected:
/**
* Pre-computed clock period in ticks. This is populated by the
* inheriting classes based on how their period is determined.
*/
Tick _clockPeriod;
/**
* Voltage domain this clock domain belongs to
*/
VoltageDomain *_voltageDomain;
/**
* Pointers to potential derived clock domains so we can propagate
* changes.
*/
std::vector<DerivedClockDomain*> children;
/**
* Pointers to members of this clock domain, so that when the clock
* period changes, we can update each member's tick.
*/
std::vector<Clocked *> members;
public:
typedef ClockDomainParams Params;
ClockDomain(const Params &p, VoltageDomain *voltage_domain);
/**
* Get the clock period.
*
* @return Clock period in ticks
*/
Tick clockPeriod() const { return _clockPeriod; }
/**
* Register a Clocked object with this ClockDomain.
*
* @param Clocked to add as a member
*/
void registerWithClockDomain(Clocked *c)
{
assert(c != NULL);
assert(std::find(members.begin(), members.end(), c) == members.end());
members.push_back(c);
}
/**
* Get the voltage domain.
*
* @return Voltage domain this clock domain belongs to
*/
inline VoltageDomain *voltageDomain() const { return _voltageDomain; }
/**
* Get the current voltage this clock domain operates at.
*
* @return Voltage applied to the clock domain
*/
double voltage() const;
/**
* Add a derived domain.
*
* @param Derived domain to add as a child
*/
void addDerivedDomain(DerivedClockDomain *clock_domain)
{ children.push_back(clock_domain); }
private:
struct ClockDomainStats : public statistics::Group
{
ClockDomainStats(ClockDomain &cd);
/**
* Stat to report clock period of clock domain
*/
statistics::Value clock;
} stats;
};
/**
* The source clock domains provides the notion of a clock domain that is
* connected to a tunable clock source. It maintains the clock period and
* provides methods for setting/getting the clock and configuration parameters
* for clock domain that handler is going to manage. This includes frequency
* values at various performance levels, domain id, and current performance
* level. Note that a performance level as requested by the software corresponds
* to one of the frequency operational points the domain can operate at.
*/
class SrcClockDomain : public ClockDomain
{
public:
typedef SrcClockDomainParams Params;
SrcClockDomain(const Params &p);
/**
* Set new clock value
* @param clock The new clock period in ticks
*/
void clockPeriod(Tick clock_period);
// Explicitly import the otherwise hidden clockPeriod
using ClockDomain::clockPeriod;
typedef int32_t DomainID;
static const DomainID emptyDomainID = -1;
/**
* @return the domainID of the domain
*/
uint32_t domainID() const { return _domainID; }
typedef uint32_t PerfLevel;
/**
* Checks whether the performance level requested exists in the current
* domain configuration
*
* @param the target performance level of the domain
*
* @return validity status of the given performance level
*/
bool validPerfLevel(PerfLevel perf_level) const {
return perf_level < numPerfLevels();
}
/**
* Sets the current performance level of the domain
*
* @param perf_level the target performance level
*/
void perfLevel(PerfLevel perf_level);
/**
* @return the current performance level of the domain
*/
PerfLevel perfLevel() const { return _perfLevel; }
/**
* Get the number of available performance levels for this clock domain.
*
* @return Number of perf levels configured for this domain.
*/
PerfLevel numPerfLevels() const {return freqOpPoints.size();}
/**
* @returns the clock period (expressed in ticks) for the current
* performance level
*/
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:
/**
* Inform other components about the changed performance level
*/
void signalPerfLevelUpdate();
/**
* List of possible frequency operational points, should be in
* descending order
* An empty list corresponds to default frequency specified for its
* clock domain, overall implying NO DVFS
*/
const std::vector<Tick> freqOpPoints;
/**
* Software recognizable id number for the domain, should be unique for
* each domain
*/
const uint32_t _domainID;
/**
* Current performance level the domain is set to.
* The performance level corresponds to one selected frequency (and related
* voltage) from the supplied list of frequencies, with perfLevel = 0 being
* the fastest performance state.
*/
PerfLevel _perfLevel;
};
/**
* The derived clock domains provides the notion of a clock domain
* that is connected to a parent clock domain that can either be a
* source clock domain or a derived clock domain. It maintains the
* clock divider and provides methods for getting the clock.
*/
class DerivedClockDomain: public ClockDomain
{
public:
typedef DerivedClockDomainParams Params;
DerivedClockDomain(const Params &p);
/**
* Called by the parent clock domain to propagate changes. This
* also involves propagating the change further to any children of
* the derived domain itself.
*/
void updateClockPeriod();
private:
/**
* Reference to the parent clock domain this clock domain derives
* its clock period from
*/
ClockDomain &parent;
/**
* Local clock divider of the domain
*/
const uint64_t clockDivider;
};
} // namespace gem5
#endif