2 * Copyright (c) 2013-2014 ARM Limited
3 * Copyright (c) 2013 Cornell University
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38 * Authors: Vasileios Spiliopoulos
41 * Stephan Diestelhorst
46 * ClockDomain declarations.
49 #ifndef __SIM_CLOCK_DOMAIN_HH__
50 #define __SIM_CLOCK_DOMAIN_HH__
54 #include "base/statistics.hh"
55 #include "params/ClockDomain.hh"
56 #include "params/DerivedClockDomain.hh"
57 #include "params/SrcClockDomain.hh"
58 #include "sim/sim_object.hh"
63 class DerivedClockDomain;
68 * The ClockDomain provides clock to group of clocked objects bundled
69 * under the same clock domain. The clock domains, in turn, are
70 * grouped into voltage domains. The clock domains provide support for
71 * a hierarchial structure with source and derived domains.
73 class ClockDomain : public SimObject
79 * Stat to report clock period of clock domain
81 Stats::Value currentClock;
86 * Pre-computed clock period in ticks. This is populated by the
87 * inheriting classes based on how their period is determined.
92 * Voltage domain this clock domain belongs to
94 VoltageDomain *_voltageDomain;
97 * Pointers to potential derived clock domains so we can propagate
100 std::vector<DerivedClockDomain*> children;
103 * Pointers to members of this clock domain, so that when the clock
104 * period changes, we can update each member's tick.
106 std::vector<ClockedObject*> members;
110 typedef ClockDomainParams Params;
111 ClockDomain(const Params *p, VoltageDomain *voltage_domain) :
114 _voltageDomain(voltage_domain) {}
119 * Get the clock period.
121 * @return Clock period in ticks
123 Tick clockPeriod() const { return _clockPeriod; }
126 * Register a ClockedObject to this ClockDomain.
128 * @param ClockedObject to add as a member
130 void registerWithClockDomain(ClockedObject *c)
133 assert(std::find(members.begin(), members.end(), c) == members.end());
134 members.push_back(c);
138 * Get the voltage domain.
140 * @return Voltage domain this clock domain belongs to
142 inline VoltageDomain *voltageDomain() const { return _voltageDomain; }
146 * Get the current voltage this clock domain operates at.
148 * @return Voltage applied to the clock domain
150 double voltage() const;
153 * Add a derived domain.
155 * @param Derived domain to add as a child
157 void addDerivedDomain(DerivedClockDomain *clock_domain)
158 { children.push_back(clock_domain); }
163 * The source clock domains provides the notion of a clock domain that is
164 * connected to a tunable clock source. It maintains the clock period and
165 * provides methods for setting/getting the clock and configuration parameters
166 * for clock domain that handler is going to manage. This includes frequency
167 * values at various performance levels, domain id, and current performance
168 * level. Note that a performance level as requested by the software corresponds
169 * to one of the frequency operational points the domain can operate at.
171 class SrcClockDomain : public ClockDomain
176 typedef SrcClockDomainParams Params;
177 SrcClockDomain(const Params *p);
180 * Set new clock value
181 * @param clock The new clock period in ticks
183 void clockPeriod(Tick clock_period);
185 // Explicitly import the otherwise hidden clockPeriod
186 using ClockDomain::clockPeriod;
188 typedef int32_t DomainID;
189 static const DomainID emptyDomainID = -1;
192 * @return the domainID of the domain
194 uint32_t domainID() const { return _domainID; }
196 typedef uint32_t PerfLevel;
198 * Checks whether the performance level requested exists in the current
199 * domain configuration
201 * @param the target performance level of the domain
203 * @return validity status of the given performance level
205 bool validPerfLevel(PerfLevel perf_level) const {
206 return perf_level < numPerfLevels();
210 * Sets the current performance level of the domain
212 * @param perf_level the target performance level
214 void perfLevel(PerfLevel perf_level);
217 * @return the current performance level of the domain
219 PerfLevel perfLevel() const { return _perfLevel; }
222 * Get the number of available performance levels for this clock domain.
224 * @return Number of perf levels configured for this domain.
226 PerfLevel numPerfLevels() const {return freqOpPoints.size();}
229 * @returns the clock period (expressed in ticks) for the current
232 Tick clkPeriodAtPerfLevel() const { return freqOpPoints[perfLevel()]; }
234 Tick clkPeriodAtPerfLevel(PerfLevel perf_level) const
236 assert(validPerfLevel(perf_level));
237 return freqOpPoints[perf_level];
241 void serialize(std::ostream &os);
242 void unserialize(Checkpoint *cp, const std::string §ion);
246 * List of possible frequency operational points, should be in
248 * An empty list corresponds to default frequency specified for its
249 * clock domain, overall implying NO DVFS
251 const std::vector<Tick> freqOpPoints;
254 * Software recognizable id number for the domain, should be unique for
257 const uint32_t _domainID;
260 * Current performance level the domain is set to.
261 * The performance level corresponds to one selected frequency (and related
262 * voltage) from the supplied list of frequencies, with perfLevel = 0 being
263 * the fastest performance state.
265 PerfLevel _perfLevel;
269 * The derived clock domains provides the notion of a clock domain
270 * that is connected to a parent clock domain that can either be a
271 * source clock domain or a derived clock domain. It maintains the
272 * clock divider and provides methods for getting the clock.
274 class DerivedClockDomain: public ClockDomain
279 typedef DerivedClockDomainParams Params;
280 DerivedClockDomain(const Params *p);
283 * Called by the parent clock domain to propagate changes. This
284 * also involves propagating the change further to any children of
285 * the derived domain itself.
287 void updateClockPeriod();
292 * Reference to the parent clock domain this clock domain derives
293 * its clock period from
298 * Local clock divider of the domain
300 const uint64_t clockDivider;