260 lines
8.7 KiB
C
260 lines
8.7 KiB
C
/*
|
|
* 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);
|
|
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__ */
|