Edit File: devfreq.h
/* * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework * for Non-CPU Devices. * * Copyright (C) 2011 Samsung Electronics * MyungJoo Ham <myungjoo.ham@samsung.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #ifndef __LINUX_DEVFREQ_H__ #define __LINUX_DEVFREQ_H__ #include <linux/device.h> #include <linux/notifier.h> #include <linux/opp.h> #define DEVFREQ_NAME_LEN 16 struct devfreq; /** * struct devfreq_dev_status - Data given from devfreq user device to * governors. Represents the performance * statistics. * @total_time: The total time represented by this instance of * devfreq_dev_status * @busy_time: The time that the device was working among the * total_time. * @current_frequency: The operating frequency. * @private_data: An entry not specified by the devfreq framework. * A device and a specific governor may have their * own protocol with private_data. However, because * this is governor-specific, a governor using this * will be only compatible with devices aware of it. */ struct devfreq_dev_status { /* both since the last measure */ unsigned long total_time; unsigned long busy_time; unsigned long current_frequency; void *private_data; }; /* * The resulting frequency should be at most this. (this bound is the * least upper bound; thus, the resulting freq should be lower or same) * If the flag is not set, the resulting frequency should be at most the * bound (greatest lower bound) */ #define DEVFREQ_FLAG_LEAST_UPPER_BOUND 0x1 /** * struct devfreq_dev_profile - Devfreq's user device profile * @initial_freq: The operating frequency when devfreq_add_device() is * called. * @polling_ms: The polling interval in ms. 0 disables polling. * @target: The device should set its operating frequency at * freq or lowest-upper-than-freq value. If freq is * higher than any operable frequency, set maximum. * Before returning, target function should set * freq at the current frequency. * The "flags" parameter's possible values are * explained above with "DEVFREQ_FLAG_*" macros. * @get_dev_status: The device should provide the current performance * status to devfreq, which is used by governors. * @get_cur_freq: The device should provide the current frequency * at which it is operating. * @exit: An optional callback that is called when devfreq * is removing the devfreq object due to error or * from devfreq_remove_device() call. If the user * has registered devfreq->nb at a notifier-head, * this is the time to unregister it. * @freq_table: Optional list of frequencies to support statistics. * @max_state: The size of freq_table. */ struct devfreq_dev_profile { unsigned long initial_freq; unsigned int polling_ms; int (*target)(struct device *dev, unsigned long *freq, u32 flags); int (*get_dev_status)(struct device *dev, struct devfreq_dev_status *stat); int (*get_cur_freq)(struct device *dev, unsigned long *freq); void (*exit)(struct device *dev); unsigned int *freq_table; unsigned int max_state; }; /** * struct devfreq_governor - Devfreq policy governor * @node: list node - contains registered devfreq governors * @name: Governor's name * @get_target_freq: Returns desired operating frequency for the device. * Basically, get_target_freq will run * devfreq_dev_profile.get_dev_status() to get the * status of the device (load = busy_time / total_time). * If no_central_polling is set, this callback is called * only with update_devfreq() notified by OPP. * @event_handler: Callback for devfreq core framework to notify events * to governors. Events include per device governor * init and exit, opp changes out of devfreq, suspend * and resume of per device devfreq during device idle. * * Note that the callbacks are called with devfreq->lock locked by devfreq. */ struct devfreq_governor { struct list_head node; const char name[DEVFREQ_NAME_LEN]; int (*get_target_freq)(struct devfreq *this, unsigned long *freq); int (*event_handler)(struct devfreq *devfreq, unsigned int event, void *data); }; /** * struct devfreq - Device devfreq structure * @node: list node - contains the devices with devfreq that have been * registered. * @lock: a mutex to protect accessing devfreq. * @dev: device registered by devfreq class. dev.parent is the device * using devfreq. * @profile: device-specific devfreq profile * @governor: method how to choose frequency based on the usage. * @governor_name: devfreq governor name for use with this devfreq * @nb: notifier block used to notify devfreq object that it should * reevaluate operable frequencies. Devfreq users may use * devfreq.nb to the corresponding register notifier call chain. * @work: delayed work for load monitoring. * @previous_freq: previously configured frequency value. * @data: Private data of the governor. The devfreq framework does not * touch this. * @min_freq: Limit minimum frequency requested by user (0: none) * @max_freq: Limit maximum frequency requested by user (0: none) * @stop_polling: devfreq polling status of a device. * @total_trans: Number of devfreq transitions * @trans_table: Statistics of devfreq transitions * @time_in_state: Statistics of devfreq states * @last_stat_updated: The last time stat updated * * This structure stores the devfreq information for a give device. * * Note that when a governor accesses entries in struct devfreq in its * functions except for the context of callbacks defined in struct * devfreq_governor, the governor should protect its access with the * struct mutex lock in struct devfreq. A governor may use this mutex * to protect its own private data in void *data as well. */ struct devfreq { struct list_head node; struct mutex lock; struct device dev; struct devfreq_dev_profile *profile; const struct devfreq_governor *governor; char governor_name[DEVFREQ_NAME_LEN]; struct notifier_block nb; struct delayed_work work; unsigned long previous_freq; void *data; /* private data for governors */ unsigned long min_freq; unsigned long max_freq; bool stop_polling; /* information for device freqeuncy transition */ unsigned int total_trans; unsigned int *trans_table; unsigned long *time_in_state; unsigned long last_stat_updated; }; #if defined(CONFIG_PM_DEVFREQ) extern struct devfreq *devfreq_add_device(struct device *dev, struct devfreq_dev_profile *profile, const char *governor_name, void *data); extern int devfreq_remove_device(struct devfreq *devfreq); /* Supposed to be called by PM_SLEEP/PM_RUNTIME callbacks */ extern int devfreq_suspend_device(struct devfreq *devfreq); extern int devfreq_resume_device(struct devfreq *devfreq); /* Helper functions for devfreq user device driver with OPP. */ extern struct opp *devfreq_recommended_opp(struct device *dev, unsigned long *freq, u32 flags); extern int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq); extern int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq); #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND) /** * struct devfreq_simple_ondemand_data - void *data fed to struct devfreq * and devfreq_add_device * @upthreshold: If the load is over this value, the frequency jumps. * Specify 0 to use the default. Valid value = 0 to 100. * @downdifferential: If the load is under upthreshold - downdifferential, * the governor may consider slowing the frequency down. * Specify 0 to use the default. Valid value = 0 to 100. * downdifferential < upthreshold must hold. * * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor, * the governor uses the default values. */ struct devfreq_simple_ondemand_data { unsigned int upthreshold; unsigned int downdifferential; }; #endif #else /* !CONFIG_PM_DEVFREQ */ static inline struct devfreq *devfreq_add_device(struct device *dev, struct devfreq_dev_profile *profile, const char *governor_name, void *data) { return NULL; } static inline int devfreq_remove_device(struct devfreq *devfreq) { return 0; } static inline int devfreq_suspend_device(struct devfreq *devfreq) { return 0; } static inline int devfreq_resume_device(struct devfreq *devfreq) { return 0; } static inline struct opp *devfreq_recommended_opp(struct device *dev, unsigned long *freq, u32 flags) { return ERR_PTR(-EINVAL); } static inline int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq) { return -EINVAL; } static inline int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq) { return -EINVAL; } #endif /* CONFIG_PM_DEVFREQ */ #endif /* __LINUX_DEVFREQ_H__ */