/* * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework * for Non-CPU Devices. * * Copyright (C) 2011 Samsung Electronics * MyungJoo Ham * * 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 #include #include #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. */ 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); }; /** * struct devfreq_governor - Devfreq policy governor * @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 { 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. * @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. * * 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; 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; }; #if defined(CONFIG_PM_DEVFREQ) extern struct devfreq *devfreq_add_device(struct device *dev, struct devfreq_dev_profile *profile, const struct devfreq_governor *governor, void *data); extern int devfreq_remove_device(struct devfreq *devfreq); 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); #ifdef CONFIG_DEVFREQ_GOV_POWERSAVE extern const struct devfreq_governor devfreq_powersave; #endif #ifdef CONFIG_DEVFREQ_GOV_PERFORMANCE extern const struct devfreq_governor devfreq_performance; #endif #ifdef CONFIG_DEVFREQ_GOV_USERSPACE extern const struct devfreq_governor devfreq_userspace; #endif #ifdef CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND extern const struct devfreq_governor devfreq_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 struct devfreq *devfreq_add_device(struct device *dev, struct devfreq_dev_profile *profile, struct devfreq_governor *governor, void *data) { return NULL; } static int devfreq_remove_device(struct devfreq *devfreq) { return 0; } static int devfreq_suspend_device(struct devfreq *devfreq) { return 0; } static int devfreq_resume_device(struct devfreq *devfreq) { return 0; } static struct opp *devfreq_recommended_opp(struct device *dev, unsigned long *freq, u32 flags) { return -EINVAL; } static int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq) { return -EINVAL; } static int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq) { return -EINVAL; } #define devfreq_powersave NULL #define devfreq_performance NULL #define devfreq_userspace NULL #define devfreq_simple_ondemand NULL #endif /* CONFIG_PM_DEVFREQ */ #endif /* __LINUX_DEVFREQ_H__ */