/*
* Copyright (c) 2013-2014 ARM Limited
* 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.
*
* Authors: Vasileios Spiliopoulos
* Akash Bagdia
* Stephan Diestelhorst
*/
/**
* @file
* DVFSHandler and DomainConfig class declaration used for managing voltage
* and frequency scaling of the various DVFS domains in the system (with each
* domain having their independent domain configuration information)
*/
#ifndef __SIM_DVFS_HANDLER_HH__
#define __SIM_DVFS_HANDLER_HH__
#include <vector>
#include "debug/DVFS.hh"
#include "params/DVFSHandler.hh"
#include "sim/clock_domain.hh"
#include "sim/eventq.hh"
#include "sim/sim_object.hh"
/**
* DVFS Handler class, maintains a list of all the domains it can handle.
* Each entry of that list is an object of the DomainConfig class, and the
* handler uses the methods provided by that class to get access to the
* configuration of each domain. The handler is responsible for setting/getting
* clock periods and voltages from clock/voltage domains.
* The handler acts the bridge between software configurable information
* for each domain as provided to the controller and the hardware
* implementation details for those domains.
*/
class DVFSHandler : public SimObject
{
public:
typedef DVFSHandlerParams Params;
DVFSHandler(const Params *p);
typedef SrcClockDomain::DomainID DomainID;
typedef SrcClockDomain::PerfLevel PerfLevel;
/**
* Get the number of domains assigned to this DVFS handler.
* @return Number of domains
*/
uint32_t numDomains() const { return domainIDList.size(); }
/**
* Get the n-th domain ID, from the domains managed by this handler.
* @return Domain ID
*/
DomainID domainID(uint32_t index) const;
/**
* Check whether a domain ID is known to the handler or not.
* @param domain_id Domain ID to check
* @return Domain ID known to handler?
*/
bool validDomainID(DomainID domain_id) const;
/**
* Get transition latency to switch between performance levels.
* @return Transition latency
*/
Tick transLatency() const { return _transLatency; }
/**
* Set a new performance level for the specified domain. The actual update
* will be delayed by transLatency().
*
* @param domain_id Software visible ID of the domain to be configured
* @param perf_level Requested performance level (0 - fast, >0 slower)
* @return status whether the setting was successful
*/
bool perfLevel(DomainID domain_id, PerfLevel perf_level);
/**
* Get the current performance level of a domain. While a change request is
* in-flight, will return the current (i.e. old, unmodified) value.
*
* @param domain_id Domain ID to query
* @return Current performance level of the specified domain
*/
PerfLevel perfLevel(DomainID domain_id) const {
assert(isEnabled());
return findDomain(domain_id)->perfLevel();
}
/**
* Read the clock period of the specified domain at the specified
* performance level.
* @param domain_id Domain ID to query
* @param perf_level Performance level of interest
* @return Clock period in ticks for the requested performance level of
* the respective domain
*/
Tick clkPeriodAtPerfLevel(DomainID domain_id, PerfLevel perf_level) const
{
SrcClockDomain *d = findDomain(domain_id);
assert(d);
PerfLevel n = d->numPerfLevels();
if (perf_level < n)
return d->clkPeriodAtPerfLevel(perf_level);
warn("DVFSHandler %s reads illegal frequency level %u from "\
"SrcClockDomain %s. Returning 0\n", name(), perf_level, d->name());
return Tick(0);
}
/**
* Read the voltage of the specified domain at the specified
* performance level.
* @param domain_id Domain ID to query
* @param perf_level Performance level of interest
* @return Voltage for the requested performance level of the respective
* domain
*/
double voltageAtPerfLevel(DomainID domain_id, PerfLevel perf_level) const;
/**
* Get the total number of available performance levels.
*
* @param domain_id Domain ID to query
* @return Number of performance levels that where configured for the
* respective domain
*/
PerfLevel numPerfLevels(PerfLevel domain_id) const
{
return findDomain(domain_id)->numPerfLevels();
}
/**
* Check enable status of the DVFS handler, when the handler is disabled, no
* request should be sent to the handler.
* @return True, if the handler is enabled
*/
bool isEnabled() const { return enableHandler; }
void serialize(CheckpointOut &cp) const override;
void unserialize(CheckpointIn &cp) override;
private:
typedef std::map<DomainID, SrcClockDomain*> Domains;
Domains domains;
/**
* List of IDs avaiable in the domain list
*/
std::vector<DomainID> domainIDList;
/**
* Clock domain of the system the handler is instantiated.
*/
SrcClockDomain* sysClkDomain;
/**
* Search for a domain based on the domain ID.
*
* @param domain_id Domain ID to search for
* @return Pointer to the source clock domain with matching ID.
*/
SrcClockDomain *findDomain(DomainID domain_id) const {
auto it = domains.find(domain_id);
panic_if(it == domains.end(),
"DVFS: Could not find a domain for ID %d.\n",domain_id );
return domains.find(domain_id)->second;
}
/**
* Disabling the DVFS handler ensures that all the DVFS migration requests
* are ignored. Domains remain at their default frequency and voltage.
*/
bool enableHandler;
/**
* This corresponds to the maximum transition latency associated with the
* hardware transitioning from a particular performance level to the other
*/
const Tick _transLatency;
/**
* Update performance level event, encapsulates all the required information
* for a future call to change a domain's performance level.
*/
struct UpdateEvent : public Event {
UpdateEvent() : Event(DVFS_Update_Pri), domainIDToSet(0),
perfLevelToSet(0) {}
/**
* Static pointer to the single DVFS hander for all the update events
*/
static DVFSHandler *dvfsHandler;
/**
* ID of the domain that will be changed by the in-flight event
*/
DomainID domainIDToSet;
/**
* Target performance level of the in-flight event
*/
PerfLevel perfLevelToSet;
/**
* Updates the performance level by modifying the clock and the voltage
* of the associated clocked objects. Gets information from
* domainIDToSet and perfLevelToSet for easier calling through an
* event.
*/
void updatePerfLevel();
void process() { updatePerfLevel(); }
};
typedef std::map<DomainID, UpdateEvent> UpdatePerfLevelEvents;
/**
* Map from domain IDs -> perf level update events, records in-flight change
* requests per domain ID.
*/
UpdatePerfLevelEvents updatePerfLevelEvents;
};
#endif // __SIM_DVFS_HANDLER_HH__