src/sim/power_domain.hh

   1 /*
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  38
  39 #ifndef __SIM_POWER_DOMAIN_HH__
  40 #define __SIM_POWER_DOMAIN_HH__
  41
  42 #include <string>
  43 #include <vector>
  44
  45 #include "base/statistics.hh"
  46 #include "params/PowerDomain.hh"
  47 #include "sim/clocked_object.hh"
  48 #include "sim/power_state.hh"
  49
  50 /**
  51  * The PowerDomain groups PowerState objects together to regulate their
  52  * power states. As the PowerDomain itself is a PowerState object, you can
  53  * create hierarchies of PowerDomains. All objects in a power domain will be in
  54  * the power state of the domain OR a more performant one.
  55  */
  56 class PowerDomain : public PowerState
  57 {
  58   public:
  59     PowerDomain(const PowerDomainParams* p);
  60     typedef PowerDomainParams Params;
  61     ~PowerDomain() override {};
  62
  63     /**
  64      * During startup, the list of possible power states the
  65      * PowerDomain can be in is populated, the power state of the
  66      * PowerDomain is set and some assertions about the PowerState objects
  67      * in the Domain are checked.
  68      */
  69     void startup() override;
  70
  71     /**
  72      * Register the change in power state in one of the leader. The power
  73      * domain will change its own power state if required and if there is a
  74      * power state, it will schedule an event to update its followers
  75      */
  76     void pwrStateChangeCallback(Enums::PwrState new_pwr_state,
  77                                 PowerState* leader);
  78
  79     /**
  80      * Function called by a follower to register itself as
  81      * a dependant of this power domain
  82      */
  83     void addFollower(PowerState* pwr_obj) override;
  84
  85   private:
  86     /**
  87      * Calculate the power state of the power domain, based upon the power
  88      * states of the leaders. This will be called if one the leaders
  89      * changes its power states.
  90      * If no inputs are given, only the leaders will be polled on their
  91      * power state. You can also pass a vector containing the power states
  92      * which the followers returned when asked to match a certain power
  93      * state (called from setFollowerPowerStates)
  94      */
  95     Enums::PwrState calculatePowerDomainState(
  96           const std::vector<Enums::PwrState> &f_states={});
  97
  98     /**
  99      * Check if a given p_state is available across all leaders and
 100      * followers in this domain.
 101      */
 102     bool isPossiblePwrState(Enums::PwrState p_state);
 103
 104     /**
 105      * Calculate the possible power states of the domain based upon the
 106      * intersection of the power states of the individual objects within
 107      * the domain. Done at startup.
 108      */
 109     void calculatePossiblePwrStates();
 110
 111     /**
 112      * Update the followers of the newly updated power state. They are
 113      * required to match the power state of the power domain i.e. go to the
 114      * same power state or a more performant one
 115      */
 116     void setFollowerPowerStates();
 117
 118   private: /* Power domain attributes */
 119      /**
 120      * List of all leaders in the PowerDomain. A leader can
 121      * independently change its power state and does not depend on the
 122      * PowerDomain to change its power state. A leader needs to be a
 123      * PowerState object and can also be another PowerDomain. Each
 124      * PowerDomain needs to have at least one leader.
 125      */
 126     std::vector<PowerState*> leaders;
 127
 128     /**
 129      * Power state requested by the leader. This is not necessarily the
 130      * power state of the domain as whole (as that one depends on the
 131      * matched power states of the followers
 132      */
 133     Enums::PwrState leaderTargetState;
 134
 135     /**
 136      * List of all followers in the PowerDomain. The power state of the
 137      * domain will determine the power state of the followers. A follower
 138      * cannot change its power state independently.
 139      */
 140     std::vector<PowerState*> followers;
 141
 142     /**
 143      * Latency with which power state changes of the leaders will ripple
 144      * through to the followers.
 145      */
 146     const Tick updateLatency = 1;
 147
 148     /**
 149      * Event to update the power states of the followers
 150      */
 151     EventWrapper<PowerDomain, &PowerDomain::setFollowerPowerStates>
 152                 pwrStateUpdateEvent;
 153
 154   protected:
 155     struct PowerDomainStats : public Stats::Group
 156     {
 157         PowerDomainStats(PowerDomain &pd);
 158
 159         void regStats() override;
 160
 161         Stats::Scalar numLeaderCalls;
 162         Stats::Scalar numLeaderCallsChangingState;
 163     } stats;
 164 };
 165
 166 #endif // __SIM_POWER_DOMAIN_HH__