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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
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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.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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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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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "sim/clock_domain.hh"
#include <algorithm>
#include <functional>
#include "base/logging.hh"
#include "base/trace.hh"
#include "debug/ClockDomain.hh"
#include "params/ClockDomain.hh"
#include "params/DerivedClockDomain.hh"
#include "params/SrcClockDomain.hh"
#include "sim/clocked_object.hh"
#include "sim/serialize.hh"
#include "sim/voltage_domain.hh"
namespace gem5
{
ClockDomain::ClockDomainStats::ClockDomainStats(ClockDomain &cd)
: statistics::Group(&cd),
ADD_STAT(clock, statistics::units::Tick::get(), "Clock period in ticks")
{
// Expose the current clock period as a stat for observability in
// the dumps
clock.scalar(cd._clockPeriod);
}
ClockDomain::ClockDomain(const Params &p, VoltageDomain *voltage_domain)
: SimObject(p),
_clockPeriod(0),
_voltageDomain(voltage_domain),
stats(*this)
{
}
double
ClockDomain::voltage() const
{
return _voltageDomain->voltage();
}
SrcClockDomain::SrcClockDomain(const Params &p) :
ClockDomain(p, p.voltage_domain),
freqOpPoints(p.clock),
_domainID(p.domain_id),
_perfLevel(p.init_perf_level)
{
VoltageDomain *vdom = p.voltage_domain;
fatal_if(freqOpPoints.empty(), "DVFS: Empty set of frequencies for "\
"domain %d %s\n", _domainID, name());
fatal_if(!vdom, "DVFS: Empty voltage domain specified for "\
"domain %d %s\n", _domainID, name());
fatal_if((vdom->numVoltages() > 1) &&
(vdom->numVoltages() != freqOpPoints.size()),
"DVFS: Number of frequency and voltage scaling points do "\
"not match: %d:%d ID: %d %s.\n", vdom->numVoltages(),
freqOpPoints.size(), _domainID, name());
// Frequency (& voltage) points should be declared in descending order,
// NOTE: Frequency is inverted to ticks, so checking for ascending ticks
fatal_if(!std::is_sorted(freqOpPoints.begin(), freqOpPoints.end()),
"DVFS: Frequency operation points not in descending order for "\
"domain with ID %d\n", _domainID);
fatal_if(_perfLevel >= freqOpPoints.size(), "DVFS: Initial DVFS point %d "\
"is outside of list for Domain ID: %d\n", _perfLevel, _domainID);
clockPeriod(freqOpPoints[_perfLevel]);
vdom->registerSrcClockDom(this);
}
void
SrcClockDomain::clockPeriod(Tick clock_period)
{
if (clock_period == 0) {
fatal("%s has a clock period of zero\n", name());
}
// Align all members to the current tick
for (auto m = members.begin(); m != members.end(); ++m) {
(*m)->updateClockPeriod();
}
_clockPeriod = clock_period;
DPRINTF(ClockDomain,
"Setting clock period to %d ticks for source clock %s\n",
_clockPeriod, name());
// inform any derived clocks they need to updated their period
for (auto c = children.begin(); c != children.end(); ++c) {
(*c)->updateClockPeriod();
}
}
void
SrcClockDomain::perfLevel(PerfLevel perf_level)
{
assert(validPerfLevel(perf_level));
if (perf_level == _perfLevel) {
// Silently ignore identical overwrites
return;
}
DPRINTF(ClockDomain, "DVFS: Switching performance level of domain %s "\
"(id: %d) from %d to %d\n", name(), domainID(), _perfLevel,
perf_level);
_perfLevel = perf_level;
signalPerfLevelUpdate();
}
void SrcClockDomain::signalPerfLevelUpdate()
{
// Signal the voltage domain that we have changed our perf level so that the
// voltage domain can recompute its performance level
voltageDomain()->sanitiseVoltages();
// Integrated switching of the actual clock value, too
clockPeriod(clkPeriodAtPerfLevel());
}
void
SrcClockDomain::serialize(CheckpointOut &cp) const
{
SERIALIZE_SCALAR(_perfLevel);
ClockDomain::serialize(cp);
}
void
SrcClockDomain::unserialize(CheckpointIn &cp)
{
ClockDomain::unserialize(cp);
UNSERIALIZE_SCALAR(_perfLevel);
}
void
SrcClockDomain::startup()
{
// Perform proper clock update when all related components have been
// created (i.e. after unserialization / object creation)
signalPerfLevelUpdate();
}
DerivedClockDomain::DerivedClockDomain(const Params &p) :
ClockDomain(p, p.clk_domain->voltageDomain()),
parent(*p.clk_domain),
clockDivider(p.clk_divider)
{
// Ensure that clock divider setting works as frequency divider and never
// work as frequency multiplier
if (clockDivider < 1) {
fatal("Clock divider param cannot be less than 1");
}
// let the parent keep track of this derived domain so that it can
// propagate changes
parent.addDerivedDomain(this);
// update our clock period based on the parents clock
updateClockPeriod();
}
void
DerivedClockDomain::updateClockPeriod()
{
// Align all members to the current tick
for (auto m = members.begin(); m != members.end(); ++m) {
(*m)->updateClockPeriod();
}
// recalculate the clock period, relying on the fact that changes
// propagate downwards in the tree
_clockPeriod = parent.clockPeriod() * clockDivider;
DPRINTF(ClockDomain,
"Setting clock period to %d ticks for derived clock %s\n",
_clockPeriod, name());
// inform any derived clocks
for (auto c = children.begin(); c != children.end(); ++c) {
(*c)->updateClockPeriod();
}
}
} // namespace gem5