2 * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
5 * Copyright (C) 2011 Samsung Electronics
6 * MyungJoo Ham <myungjoo.ham@samsung.com>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
13 #include <linux/kernel.h>
14 #include <linux/sched.h>
15 #include <linux/errno.h>
16 #include <linux/err.h>
17 #include <linux/init.h>
18 #include <linux/export.h>
19 #include <linux/slab.h>
20 #include <linux/stat.h>
21 #include <linux/pm_opp.h>
22 #include <linux/devfreq.h>
23 #include <linux/workqueue.h>
24 #include <linux/platform_device.h>
25 #include <linux/list.h>
26 #include <linux/printk.h>
27 #include <linux/hrtimer.h>
31 static struct class *devfreq_class
;
34 * devfreq core provides delayed work based load monitoring helper
35 * functions. Governors can use these or can implement their own
36 * monitoring mechanism.
38 static struct workqueue_struct
*devfreq_wq
;
40 /* The list of all device-devfreq governors */
41 static LIST_HEAD(devfreq_governor_list
);
42 /* The list of all device-devfreq */
43 static LIST_HEAD(devfreq_list
);
44 static DEFINE_MUTEX(devfreq_list_lock
);
47 * find_device_devfreq() - find devfreq struct using device pointer
48 * @dev: device pointer used to lookup device devfreq.
50 * Search the list of device devfreqs and return the matched device's
51 * devfreq info. devfreq_list_lock should be held by the caller.
53 static struct devfreq
*find_device_devfreq(struct device
*dev
)
55 struct devfreq
*tmp_devfreq
;
57 if (IS_ERR_OR_NULL(dev
)) {
58 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__
);
59 return ERR_PTR(-EINVAL
);
61 WARN(!mutex_is_locked(&devfreq_list_lock
),
62 "devfreq_list_lock must be locked.");
64 list_for_each_entry(tmp_devfreq
, &devfreq_list
, node
) {
65 if (tmp_devfreq
->dev
.parent
== dev
)
69 return ERR_PTR(-ENODEV
);
73 * devfreq_get_freq_level() - Lookup freq_table for the frequency
74 * @devfreq: the devfreq instance
75 * @freq: the target frequency
77 static int devfreq_get_freq_level(struct devfreq
*devfreq
, unsigned long freq
)
81 for (lev
= 0; lev
< devfreq
->profile
->max_state
; lev
++)
82 if (freq
== devfreq
->profile
->freq_table
[lev
])
89 * devfreq_set_freq_table() - Initialize freq_table for the frequency
90 * @devfreq: the devfreq instance
92 static void devfreq_set_freq_table(struct devfreq
*devfreq
)
94 struct devfreq_dev_profile
*profile
= devfreq
->profile
;
95 struct dev_pm_opp
*opp
;
99 /* Initialize the freq_table from OPP table */
100 count
= dev_pm_opp_get_opp_count(devfreq
->dev
.parent
);
104 profile
->max_state
= count
;
105 profile
->freq_table
= devm_kcalloc(devfreq
->dev
.parent
,
107 sizeof(*profile
->freq_table
),
109 if (!profile
->freq_table
) {
110 profile
->max_state
= 0;
115 for (i
= 0, freq
= 0; i
< profile
->max_state
; i
++, freq
++) {
116 opp
= dev_pm_opp_find_freq_ceil(devfreq
->dev
.parent
, &freq
);
118 devm_kfree(devfreq
->dev
.parent
, profile
->freq_table
);
119 profile
->max_state
= 0;
123 profile
->freq_table
[i
] = freq
;
129 * devfreq_update_status() - Update statistics of devfreq behavior
130 * @devfreq: the devfreq instance
131 * @freq: the update target frequency
133 int devfreq_update_status(struct devfreq
*devfreq
, unsigned long freq
)
135 int lev
, prev_lev
, ret
= 0;
136 unsigned long cur_time
;
140 /* Immediately exit if previous_freq is not initialized yet. */
141 if (!devfreq
->previous_freq
)
144 prev_lev
= devfreq_get_freq_level(devfreq
, devfreq
->previous_freq
);
150 devfreq
->time_in_state
[prev_lev
] +=
151 cur_time
- devfreq
->last_stat_updated
;
153 lev
= devfreq_get_freq_level(devfreq
, freq
);
159 if (lev
!= prev_lev
) {
160 devfreq
->trans_table
[(prev_lev
*
161 devfreq
->profile
->max_state
) + lev
]++;
162 devfreq
->total_trans
++;
166 devfreq
->last_stat_updated
= cur_time
;
169 EXPORT_SYMBOL(devfreq_update_status
);
172 * find_devfreq_governor() - find devfreq governor from name
173 * @name: name of the governor
175 * Search the list of devfreq governors and return the matched
176 * governor's pointer. devfreq_list_lock should be held by the caller.
178 static struct devfreq_governor
*find_devfreq_governor(const char *name
)
180 struct devfreq_governor
*tmp_governor
;
182 if (IS_ERR_OR_NULL(name
)) {
183 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__
);
184 return ERR_PTR(-EINVAL
);
186 WARN(!mutex_is_locked(&devfreq_list_lock
),
187 "devfreq_list_lock must be locked.");
189 list_for_each_entry(tmp_governor
, &devfreq_governor_list
, node
) {
190 if (!strncmp(tmp_governor
->name
, name
, DEVFREQ_NAME_LEN
))
194 return ERR_PTR(-ENODEV
);
197 static int devfreq_notify_transition(struct devfreq
*devfreq
,
198 struct devfreq_freqs
*freqs
, unsigned int state
)
204 case DEVFREQ_PRECHANGE
:
205 srcu_notifier_call_chain(&devfreq
->transition_notifier_list
,
206 DEVFREQ_PRECHANGE
, freqs
);
209 case DEVFREQ_POSTCHANGE
:
210 srcu_notifier_call_chain(&devfreq
->transition_notifier_list
,
211 DEVFREQ_POSTCHANGE
, freqs
);
220 /* Load monitoring helper functions for governors use */
223 * update_devfreq() - Reevaluate the device and configure frequency.
224 * @devfreq: the devfreq instance.
226 * Note: Lock devfreq->lock before calling update_devfreq
227 * This function is exported for governors.
229 int update_devfreq(struct devfreq
*devfreq
)
231 struct devfreq_freqs freqs
;
232 unsigned long freq
, cur_freq
;
236 if (!mutex_is_locked(&devfreq
->lock
)) {
237 WARN(true, "devfreq->lock must be locked by the caller.\n");
241 if (!devfreq
->governor
)
244 /* Reevaluate the proper frequency */
245 err
= devfreq
->governor
->get_target_freq(devfreq
, &freq
);
250 * Adjust the frequency with user freq and QoS.
252 * List from the highest priority
257 if (devfreq
->min_freq
&& freq
< devfreq
->min_freq
) {
258 freq
= devfreq
->min_freq
;
259 flags
&= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND
; /* Use GLB */
261 if (devfreq
->max_freq
&& freq
> devfreq
->max_freq
) {
262 freq
= devfreq
->max_freq
;
263 flags
|= DEVFREQ_FLAG_LEAST_UPPER_BOUND
; /* Use LUB */
266 if (devfreq
->profile
->get_cur_freq
)
267 devfreq
->profile
->get_cur_freq(devfreq
->dev
.parent
, &cur_freq
);
269 cur_freq
= devfreq
->previous_freq
;
271 freqs
.old
= cur_freq
;
273 devfreq_notify_transition(devfreq
, &freqs
, DEVFREQ_PRECHANGE
);
275 err
= devfreq
->profile
->target(devfreq
->dev
.parent
, &freq
, flags
);
277 freqs
.new = cur_freq
;
278 devfreq_notify_transition(devfreq
, &freqs
, DEVFREQ_POSTCHANGE
);
283 devfreq_notify_transition(devfreq
, &freqs
, DEVFREQ_POSTCHANGE
);
285 if (devfreq
->profile
->freq_table
)
286 if (devfreq_update_status(devfreq
, freq
))
287 dev_err(&devfreq
->dev
,
288 "Couldn't update frequency transition information.\n");
290 devfreq
->previous_freq
= freq
;
293 EXPORT_SYMBOL(update_devfreq
);
296 * devfreq_monitor() - Periodically poll devfreq objects.
297 * @work: the work struct used to run devfreq_monitor periodically.
300 static void devfreq_monitor(struct work_struct
*work
)
303 struct devfreq
*devfreq
= container_of(work
,
304 struct devfreq
, work
.work
);
306 mutex_lock(&devfreq
->lock
);
307 err
= update_devfreq(devfreq
);
309 dev_err(&devfreq
->dev
, "dvfs failed with (%d) error\n", err
);
311 queue_delayed_work(devfreq_wq
, &devfreq
->work
,
312 msecs_to_jiffies(devfreq
->profile
->polling_ms
));
313 mutex_unlock(&devfreq
->lock
);
317 * devfreq_monitor_start() - Start load monitoring of devfreq instance
318 * @devfreq: the devfreq instance.
320 * Helper function for starting devfreq device load monitoing. By
321 * default delayed work based monitoring is supported. Function
322 * to be called from governor in response to DEVFREQ_GOV_START
323 * event when device is added to devfreq framework.
325 void devfreq_monitor_start(struct devfreq
*devfreq
)
327 INIT_DEFERRABLE_WORK(&devfreq
->work
, devfreq_monitor
);
328 if (devfreq
->profile
->polling_ms
)
329 queue_delayed_work(devfreq_wq
, &devfreq
->work
,
330 msecs_to_jiffies(devfreq
->profile
->polling_ms
));
332 EXPORT_SYMBOL(devfreq_monitor_start
);
335 * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
336 * @devfreq: the devfreq instance.
338 * Helper function to stop devfreq device load monitoing. Function
339 * to be called from governor in response to DEVFREQ_GOV_STOP
340 * event when device is removed from devfreq framework.
342 void devfreq_monitor_stop(struct devfreq
*devfreq
)
344 cancel_delayed_work_sync(&devfreq
->work
);
346 EXPORT_SYMBOL(devfreq_monitor_stop
);
349 * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
350 * @devfreq: the devfreq instance.
352 * Helper function to suspend devfreq device load monitoing. Function
353 * to be called from governor in response to DEVFREQ_GOV_SUSPEND
354 * event or when polling interval is set to zero.
356 * Note: Though this function is same as devfreq_monitor_stop(),
357 * intentionally kept separate to provide hooks for collecting
358 * transition statistics.
360 void devfreq_monitor_suspend(struct devfreq
*devfreq
)
362 mutex_lock(&devfreq
->lock
);
363 if (devfreq
->stop_polling
) {
364 mutex_unlock(&devfreq
->lock
);
368 devfreq_update_status(devfreq
, devfreq
->previous_freq
);
369 devfreq
->stop_polling
= true;
370 mutex_unlock(&devfreq
->lock
);
371 cancel_delayed_work_sync(&devfreq
->work
);
373 EXPORT_SYMBOL(devfreq_monitor_suspend
);
376 * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
377 * @devfreq: the devfreq instance.
379 * Helper function to resume devfreq device load monitoing. Function
380 * to be called from governor in response to DEVFREQ_GOV_RESUME
381 * event or when polling interval is set to non-zero.
383 void devfreq_monitor_resume(struct devfreq
*devfreq
)
387 mutex_lock(&devfreq
->lock
);
388 if (!devfreq
->stop_polling
)
391 if (!delayed_work_pending(&devfreq
->work
) &&
392 devfreq
->profile
->polling_ms
)
393 queue_delayed_work(devfreq_wq
, &devfreq
->work
,
394 msecs_to_jiffies(devfreq
->profile
->polling_ms
));
396 devfreq
->last_stat_updated
= jiffies
;
397 devfreq
->stop_polling
= false;
399 if (devfreq
->profile
->get_cur_freq
&&
400 !devfreq
->profile
->get_cur_freq(devfreq
->dev
.parent
, &freq
))
401 devfreq
->previous_freq
= freq
;
404 mutex_unlock(&devfreq
->lock
);
406 EXPORT_SYMBOL(devfreq_monitor_resume
);
409 * devfreq_interval_update() - Update device devfreq monitoring interval
410 * @devfreq: the devfreq instance.
411 * @delay: new polling interval to be set.
413 * Helper function to set new load monitoring polling interval. Function
414 * to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
416 void devfreq_interval_update(struct devfreq
*devfreq
, unsigned int *delay
)
418 unsigned int cur_delay
= devfreq
->profile
->polling_ms
;
419 unsigned int new_delay
= *delay
;
421 mutex_lock(&devfreq
->lock
);
422 devfreq
->profile
->polling_ms
= new_delay
;
424 if (devfreq
->stop_polling
)
427 /* if new delay is zero, stop polling */
429 mutex_unlock(&devfreq
->lock
);
430 cancel_delayed_work_sync(&devfreq
->work
);
434 /* if current delay is zero, start polling with new delay */
436 queue_delayed_work(devfreq_wq
, &devfreq
->work
,
437 msecs_to_jiffies(devfreq
->profile
->polling_ms
));
441 /* if current delay is greater than new delay, restart polling */
442 if (cur_delay
> new_delay
) {
443 mutex_unlock(&devfreq
->lock
);
444 cancel_delayed_work_sync(&devfreq
->work
);
445 mutex_lock(&devfreq
->lock
);
446 if (!devfreq
->stop_polling
)
447 queue_delayed_work(devfreq_wq
, &devfreq
->work
,
448 msecs_to_jiffies(devfreq
->profile
->polling_ms
));
451 mutex_unlock(&devfreq
->lock
);
453 EXPORT_SYMBOL(devfreq_interval_update
);
456 * devfreq_notifier_call() - Notify that the device frequency requirements
457 * has been changed out of devfreq framework.
458 * @nb: the notifier_block (supposed to be devfreq->nb)
462 * Called by a notifier that uses devfreq->nb.
464 static int devfreq_notifier_call(struct notifier_block
*nb
, unsigned long type
,
467 struct devfreq
*devfreq
= container_of(nb
, struct devfreq
, nb
);
470 mutex_lock(&devfreq
->lock
);
471 ret
= update_devfreq(devfreq
);
472 mutex_unlock(&devfreq
->lock
);
478 * _remove_devfreq() - Remove devfreq from the list and release its resources.
479 * @devfreq: the devfreq struct
481 static void _remove_devfreq(struct devfreq
*devfreq
)
483 mutex_lock(&devfreq_list_lock
);
484 if (IS_ERR(find_device_devfreq(devfreq
->dev
.parent
))) {
485 mutex_unlock(&devfreq_list_lock
);
486 dev_warn(&devfreq
->dev
, "releasing devfreq which doesn't exist\n");
489 list_del(&devfreq
->node
);
490 mutex_unlock(&devfreq_list_lock
);
492 if (devfreq
->governor
)
493 devfreq
->governor
->event_handler(devfreq
,
494 DEVFREQ_GOV_STOP
, NULL
);
496 if (devfreq
->profile
->exit
)
497 devfreq
->profile
->exit(devfreq
->dev
.parent
);
499 mutex_destroy(&devfreq
->lock
);
504 * devfreq_dev_release() - Callback for struct device to release the device.
505 * @dev: the devfreq device
507 * This calls _remove_devfreq() if _remove_devfreq() is not called.
509 static void devfreq_dev_release(struct device
*dev
)
511 struct devfreq
*devfreq
= to_devfreq(dev
);
513 _remove_devfreq(devfreq
);
517 * devfreq_add_device() - Add devfreq feature to the device
518 * @dev: the device to add devfreq feature.
519 * @profile: device-specific profile to run devfreq.
520 * @governor_name: name of the policy to choose frequency.
521 * @data: private data for the governor. The devfreq framework does not
524 struct devfreq
*devfreq_add_device(struct device
*dev
,
525 struct devfreq_dev_profile
*profile
,
526 const char *governor_name
,
529 struct devfreq
*devfreq
;
530 struct devfreq_governor
*governor
;
533 if (!dev
|| !profile
|| !governor_name
) {
534 dev_err(dev
, "%s: Invalid parameters.\n", __func__
);
535 return ERR_PTR(-EINVAL
);
538 mutex_lock(&devfreq_list_lock
);
539 devfreq
= find_device_devfreq(dev
);
540 mutex_unlock(&devfreq_list_lock
);
541 if (!IS_ERR(devfreq
)) {
542 dev_err(dev
, "%s: Unable to create devfreq for the device. It already has one.\n", __func__
);
547 devfreq
= kzalloc(sizeof(struct devfreq
), GFP_KERNEL
);
549 dev_err(dev
, "%s: Unable to create devfreq for the device\n",
555 mutex_init(&devfreq
->lock
);
556 mutex_lock(&devfreq
->lock
);
557 devfreq
->dev
.parent
= dev
;
558 devfreq
->dev
.class = devfreq_class
;
559 devfreq
->dev
.release
= devfreq_dev_release
;
560 devfreq
->profile
= profile
;
561 strncpy(devfreq
->governor_name
, governor_name
, DEVFREQ_NAME_LEN
);
562 devfreq
->previous_freq
= profile
->initial_freq
;
563 devfreq
->last_status
.current_frequency
= profile
->initial_freq
;
564 devfreq
->data
= data
;
565 devfreq
->nb
.notifier_call
= devfreq_notifier_call
;
567 if (!devfreq
->profile
->max_state
&& !devfreq
->profile
->freq_table
) {
568 mutex_unlock(&devfreq
->lock
);
569 devfreq_set_freq_table(devfreq
);
570 mutex_lock(&devfreq
->lock
);
573 dev_set_name(&devfreq
->dev
, "%s", dev_name(dev
));
574 err
= device_register(&devfreq
->dev
);
576 mutex_unlock(&devfreq
->lock
);
580 devfreq
->trans_table
= devm_kzalloc(&devfreq
->dev
, sizeof(unsigned int) *
581 devfreq
->profile
->max_state
*
582 devfreq
->profile
->max_state
,
584 devfreq
->time_in_state
= devm_kzalloc(&devfreq
->dev
, sizeof(unsigned long) *
585 devfreq
->profile
->max_state
,
587 devfreq
->last_stat_updated
= jiffies
;
589 srcu_init_notifier_head(&devfreq
->transition_notifier_list
);
591 mutex_unlock(&devfreq
->lock
);
593 mutex_lock(&devfreq_list_lock
);
594 list_add(&devfreq
->node
, &devfreq_list
);
596 governor
= find_devfreq_governor(devfreq
->governor_name
);
597 if (IS_ERR(governor
)) {
598 dev_err(dev
, "%s: Unable to find governor for the device\n",
600 err
= PTR_ERR(governor
);
604 devfreq
->governor
= governor
;
605 err
= devfreq
->governor
->event_handler(devfreq
, DEVFREQ_GOV_START
,
608 dev_err(dev
, "%s: Unable to start governor for the device\n",
612 mutex_unlock(&devfreq_list_lock
);
617 list_del(&devfreq
->node
);
618 mutex_unlock(&devfreq_list_lock
);
620 device_unregister(&devfreq
->dev
);
624 EXPORT_SYMBOL(devfreq_add_device
);
627 * devfreq_remove_device() - Remove devfreq feature from a device.
628 * @devfreq: the devfreq instance to be removed
630 * The opposite of devfreq_add_device().
632 int devfreq_remove_device(struct devfreq
*devfreq
)
637 device_unregister(&devfreq
->dev
);
641 EXPORT_SYMBOL(devfreq_remove_device
);
643 static int devm_devfreq_dev_match(struct device
*dev
, void *res
, void *data
)
645 struct devfreq
**r
= res
;
647 if (WARN_ON(!r
|| !*r
))
653 static void devm_devfreq_dev_release(struct device
*dev
, void *res
)
655 devfreq_remove_device(*(struct devfreq
**)res
);
659 * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
660 * @dev: the device to add devfreq feature.
661 * @profile: device-specific profile to run devfreq.
662 * @governor_name: name of the policy to choose frequency.
663 * @data: private data for the governor. The devfreq framework does not
666 * This function manages automatically the memory of devfreq device using device
667 * resource management and simplify the free operation for memory of devfreq
670 struct devfreq
*devm_devfreq_add_device(struct device
*dev
,
671 struct devfreq_dev_profile
*profile
,
672 const char *governor_name
,
675 struct devfreq
**ptr
, *devfreq
;
677 ptr
= devres_alloc(devm_devfreq_dev_release
, sizeof(*ptr
), GFP_KERNEL
);
679 return ERR_PTR(-ENOMEM
);
681 devfreq
= devfreq_add_device(dev
, profile
, governor_name
, data
);
682 if (IS_ERR(devfreq
)) {
684 return ERR_PTR(-ENOMEM
);
688 devres_add(dev
, ptr
);
692 EXPORT_SYMBOL(devm_devfreq_add_device
);
696 * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
697 * @dev - instance to the given device
698 * @index - index into list of devfreq
700 * return the instance of devfreq device
702 struct devfreq
*devfreq_get_devfreq_by_phandle(struct device
*dev
, int index
)
704 struct device_node
*node
;
705 struct devfreq
*devfreq
;
708 return ERR_PTR(-EINVAL
);
711 return ERR_PTR(-EINVAL
);
713 node
= of_parse_phandle(dev
->of_node
, "devfreq", index
);
715 return ERR_PTR(-ENODEV
);
717 mutex_lock(&devfreq_list_lock
);
718 list_for_each_entry(devfreq
, &devfreq_list
, node
) {
719 if (devfreq
->dev
.parent
720 && devfreq
->dev
.parent
->of_node
== node
) {
721 mutex_unlock(&devfreq_list_lock
);
726 mutex_unlock(&devfreq_list_lock
);
729 return ERR_PTR(-EPROBE_DEFER
);
732 struct devfreq
*devfreq_get_devfreq_by_phandle(struct device
*dev
, int index
)
734 return ERR_PTR(-ENODEV
);
736 #endif /* CONFIG_OF */
737 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle
);
740 * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
741 * @dev: the device to add devfreq feature.
742 * @devfreq: the devfreq instance to be removed
744 void devm_devfreq_remove_device(struct device
*dev
, struct devfreq
*devfreq
)
746 WARN_ON(devres_release(dev
, devm_devfreq_dev_release
,
747 devm_devfreq_dev_match
, devfreq
));
749 EXPORT_SYMBOL(devm_devfreq_remove_device
);
752 * devfreq_suspend_device() - Suspend devfreq of a device.
753 * @devfreq: the devfreq instance to be suspended
755 * This function is intended to be called by the pm callbacks
756 * (e.g., runtime_suspend, suspend) of the device driver that
759 int devfreq_suspend_device(struct devfreq
*devfreq
)
764 if (!devfreq
->governor
)
767 return devfreq
->governor
->event_handler(devfreq
,
768 DEVFREQ_GOV_SUSPEND
, NULL
);
770 EXPORT_SYMBOL(devfreq_suspend_device
);
773 * devfreq_resume_device() - Resume devfreq of a device.
774 * @devfreq: the devfreq instance to be resumed
776 * This function is intended to be called by the pm callbacks
777 * (e.g., runtime_resume, resume) of the device driver that
780 int devfreq_resume_device(struct devfreq
*devfreq
)
785 if (!devfreq
->governor
)
788 return devfreq
->governor
->event_handler(devfreq
,
789 DEVFREQ_GOV_RESUME
, NULL
);
791 EXPORT_SYMBOL(devfreq_resume_device
);
794 * devfreq_add_governor() - Add devfreq governor
795 * @governor: the devfreq governor to be added
797 int devfreq_add_governor(struct devfreq_governor
*governor
)
799 struct devfreq_governor
*g
;
800 struct devfreq
*devfreq
;
804 pr_err("%s: Invalid parameters.\n", __func__
);
808 mutex_lock(&devfreq_list_lock
);
809 g
= find_devfreq_governor(governor
->name
);
811 pr_err("%s: governor %s already registered\n", __func__
,
817 list_add(&governor
->node
, &devfreq_governor_list
);
819 list_for_each_entry(devfreq
, &devfreq_list
, node
) {
821 struct device
*dev
= devfreq
->dev
.parent
;
823 if (!strncmp(devfreq
->governor_name
, governor
->name
,
825 /* The following should never occur */
826 if (devfreq
->governor
) {
828 "%s: Governor %s already present\n",
829 __func__
, devfreq
->governor
->name
);
830 ret
= devfreq
->governor
->event_handler(devfreq
,
831 DEVFREQ_GOV_STOP
, NULL
);
834 "%s: Governor %s stop = %d\n",
836 devfreq
->governor
->name
, ret
);
840 devfreq
->governor
= governor
;
841 ret
= devfreq
->governor
->event_handler(devfreq
,
842 DEVFREQ_GOV_START
, NULL
);
844 dev_warn(dev
, "%s: Governor %s start=%d\n",
845 __func__
, devfreq
->governor
->name
,
852 mutex_unlock(&devfreq_list_lock
);
856 EXPORT_SYMBOL(devfreq_add_governor
);
859 * devfreq_remove_governor() - Remove devfreq feature from a device.
860 * @governor: the devfreq governor to be removed
862 int devfreq_remove_governor(struct devfreq_governor
*governor
)
864 struct devfreq_governor
*g
;
865 struct devfreq
*devfreq
;
869 pr_err("%s: Invalid parameters.\n", __func__
);
873 mutex_lock(&devfreq_list_lock
);
874 g
= find_devfreq_governor(governor
->name
);
876 pr_err("%s: governor %s not registered\n", __func__
,
881 list_for_each_entry(devfreq
, &devfreq_list
, node
) {
883 struct device
*dev
= devfreq
->dev
.parent
;
885 if (!strncmp(devfreq
->governor_name
, governor
->name
,
887 /* we should have a devfreq governor! */
888 if (!devfreq
->governor
) {
889 dev_warn(dev
, "%s: Governor %s NOT present\n",
890 __func__
, governor
->name
);
894 ret
= devfreq
->governor
->event_handler(devfreq
,
895 DEVFREQ_GOV_STOP
, NULL
);
897 dev_warn(dev
, "%s: Governor %s stop=%d\n",
898 __func__
, devfreq
->governor
->name
,
901 devfreq
->governor
= NULL
;
905 list_del(&governor
->node
);
907 mutex_unlock(&devfreq_list_lock
);
911 EXPORT_SYMBOL(devfreq_remove_governor
);
913 static ssize_t
governor_show(struct device
*dev
,
914 struct device_attribute
*attr
, char *buf
)
916 if (!to_devfreq(dev
)->governor
)
919 return sprintf(buf
, "%s\n", to_devfreq(dev
)->governor
->name
);
922 static ssize_t
governor_store(struct device
*dev
, struct device_attribute
*attr
,
923 const char *buf
, size_t count
)
925 struct devfreq
*df
= to_devfreq(dev
);
927 char str_governor
[DEVFREQ_NAME_LEN
+ 1];
928 struct devfreq_governor
*governor
;
930 ret
= sscanf(buf
, "%" __stringify(DEVFREQ_NAME_LEN
) "s", str_governor
);
934 mutex_lock(&devfreq_list_lock
);
935 governor
= find_devfreq_governor(str_governor
);
936 if (IS_ERR(governor
)) {
937 ret
= PTR_ERR(governor
);
940 if (df
->governor
== governor
) {
943 } else if (df
->governor
->immutable
|| governor
->immutable
) {
949 ret
= df
->governor
->event_handler(df
, DEVFREQ_GOV_STOP
, NULL
);
951 dev_warn(dev
, "%s: Governor %s not stopped(%d)\n",
952 __func__
, df
->governor
->name
, ret
);
956 df
->governor
= governor
;
957 strncpy(df
->governor_name
, governor
->name
, DEVFREQ_NAME_LEN
);
958 ret
= df
->governor
->event_handler(df
, DEVFREQ_GOV_START
, NULL
);
960 dev_warn(dev
, "%s: Governor %s not started(%d)\n",
961 __func__
, df
->governor
->name
, ret
);
963 mutex_unlock(&devfreq_list_lock
);
969 static DEVICE_ATTR_RW(governor
);
971 static ssize_t
available_governors_show(struct device
*d
,
972 struct device_attribute
*attr
,
975 struct devfreq
*df
= to_devfreq(d
);
978 mutex_lock(&devfreq_list_lock
);
981 * The devfreq with immutable governor (e.g., passive) shows
984 if (df
->governor
->immutable
) {
985 count
= scnprintf(&buf
[count
], DEVFREQ_NAME_LEN
,
986 "%s ", df
->governor_name
);
988 * The devfreq device shows the registered governor except for
989 * immutable governors such as passive governor .
992 struct devfreq_governor
*governor
;
994 list_for_each_entry(governor
, &devfreq_governor_list
, node
) {
995 if (governor
->immutable
)
997 count
+= scnprintf(&buf
[count
], (PAGE_SIZE
- count
- 2),
998 "%s ", governor
->name
);
1002 mutex_unlock(&devfreq_list_lock
);
1004 /* Truncate the trailing space */
1008 count
+= sprintf(&buf
[count
], "\n");
1012 static DEVICE_ATTR_RO(available_governors
);
1014 static ssize_t
cur_freq_show(struct device
*dev
, struct device_attribute
*attr
,
1018 struct devfreq
*devfreq
= to_devfreq(dev
);
1020 if (devfreq
->profile
->get_cur_freq
&&
1021 !devfreq
->profile
->get_cur_freq(devfreq
->dev
.parent
, &freq
))
1022 return sprintf(buf
, "%lu\n", freq
);
1024 return sprintf(buf
, "%lu\n", devfreq
->previous_freq
);
1026 static DEVICE_ATTR_RO(cur_freq
);
1028 static ssize_t
target_freq_show(struct device
*dev
,
1029 struct device_attribute
*attr
, char *buf
)
1031 return sprintf(buf
, "%lu\n", to_devfreq(dev
)->previous_freq
);
1033 static DEVICE_ATTR_RO(target_freq
);
1035 static ssize_t
polling_interval_show(struct device
*dev
,
1036 struct device_attribute
*attr
, char *buf
)
1038 return sprintf(buf
, "%d\n", to_devfreq(dev
)->profile
->polling_ms
);
1041 static ssize_t
polling_interval_store(struct device
*dev
,
1042 struct device_attribute
*attr
,
1043 const char *buf
, size_t count
)
1045 struct devfreq
*df
= to_devfreq(dev
);
1052 ret
= sscanf(buf
, "%u", &value
);
1056 df
->governor
->event_handler(df
, DEVFREQ_GOV_INTERVAL
, &value
);
1061 static DEVICE_ATTR_RW(polling_interval
);
1063 static ssize_t
min_freq_store(struct device
*dev
, struct device_attribute
*attr
,
1064 const char *buf
, size_t count
)
1066 struct devfreq
*df
= to_devfreq(dev
);
1067 unsigned long value
;
1071 ret
= sscanf(buf
, "%lu", &value
);
1075 mutex_lock(&df
->lock
);
1077 if (value
&& max
&& value
> max
) {
1082 df
->min_freq
= value
;
1086 mutex_unlock(&df
->lock
);
1090 static ssize_t
max_freq_store(struct device
*dev
, struct device_attribute
*attr
,
1091 const char *buf
, size_t count
)
1093 struct devfreq
*df
= to_devfreq(dev
);
1094 unsigned long value
;
1098 ret
= sscanf(buf
, "%lu", &value
);
1102 mutex_lock(&df
->lock
);
1104 if (value
&& min
&& value
< min
) {
1109 df
->max_freq
= value
;
1113 mutex_unlock(&df
->lock
);
1117 #define show_one(name) \
1118 static ssize_t name##_show \
1119 (struct device *dev, struct device_attribute *attr, char *buf) \
1121 return sprintf(buf, "%lu\n", to_devfreq(dev)->name); \
1126 static DEVICE_ATTR_RW(min_freq
);
1127 static DEVICE_ATTR_RW(max_freq
);
1129 static ssize_t
available_frequencies_show(struct device
*d
,
1130 struct device_attribute
*attr
,
1133 struct devfreq
*df
= to_devfreq(d
);
1134 struct device
*dev
= df
->dev
.parent
;
1135 struct dev_pm_opp
*opp
;
1137 unsigned long freq
= 0;
1141 opp
= dev_pm_opp_find_freq_ceil(dev
, &freq
);
1145 count
+= scnprintf(&buf
[count
], (PAGE_SIZE
- count
- 2),
1151 /* Truncate the trailing space */
1155 count
+= sprintf(&buf
[count
], "\n");
1159 static DEVICE_ATTR_RO(available_frequencies
);
1161 static ssize_t
trans_stat_show(struct device
*dev
,
1162 struct device_attribute
*attr
, char *buf
)
1164 struct devfreq
*devfreq
= to_devfreq(dev
);
1167 unsigned int max_state
= devfreq
->profile
->max_state
;
1169 if (!devfreq
->stop_polling
&&
1170 devfreq_update_status(devfreq
, devfreq
->previous_freq
))
1173 return sprintf(buf
, "Not Supported.\n");
1175 len
= sprintf(buf
, " From : To\n");
1176 len
+= sprintf(buf
+ len
, " :");
1177 for (i
= 0; i
< max_state
; i
++)
1178 len
+= sprintf(buf
+ len
, "%10lu",
1179 devfreq
->profile
->freq_table
[i
]);
1181 len
+= sprintf(buf
+ len
, " time(ms)\n");
1183 for (i
= 0; i
< max_state
; i
++) {
1184 if (devfreq
->profile
->freq_table
[i
]
1185 == devfreq
->previous_freq
) {
1186 len
+= sprintf(buf
+ len
, "*");
1188 len
+= sprintf(buf
+ len
, " ");
1190 len
+= sprintf(buf
+ len
, "%10lu:",
1191 devfreq
->profile
->freq_table
[i
]);
1192 for (j
= 0; j
< max_state
; j
++)
1193 len
+= sprintf(buf
+ len
, "%10u",
1194 devfreq
->trans_table
[(i
* max_state
) + j
]);
1195 len
+= sprintf(buf
+ len
, "%10u\n",
1196 jiffies_to_msecs(devfreq
->time_in_state
[i
]));
1199 len
+= sprintf(buf
+ len
, "Total transition : %u\n",
1200 devfreq
->total_trans
);
1203 static DEVICE_ATTR_RO(trans_stat
);
1205 static struct attribute
*devfreq_attrs
[] = {
1206 &dev_attr_governor
.attr
,
1207 &dev_attr_available_governors
.attr
,
1208 &dev_attr_cur_freq
.attr
,
1209 &dev_attr_available_frequencies
.attr
,
1210 &dev_attr_target_freq
.attr
,
1211 &dev_attr_polling_interval
.attr
,
1212 &dev_attr_min_freq
.attr
,
1213 &dev_attr_max_freq
.attr
,
1214 &dev_attr_trans_stat
.attr
,
1217 ATTRIBUTE_GROUPS(devfreq
);
1219 static int __init
devfreq_init(void)
1221 devfreq_class
= class_create(THIS_MODULE
, "devfreq");
1222 if (IS_ERR(devfreq_class
)) {
1223 pr_err("%s: couldn't create class\n", __FILE__
);
1224 return PTR_ERR(devfreq_class
);
1227 devfreq_wq
= create_freezable_workqueue("devfreq_wq");
1229 class_destroy(devfreq_class
);
1230 pr_err("%s: couldn't create workqueue\n", __FILE__
);
1233 devfreq_class
->dev_groups
= devfreq_groups
;
1237 subsys_initcall(devfreq_init
);
1240 * The followings are helper functions for devfreq user device drivers with
1245 * devfreq_recommended_opp() - Helper function to get proper OPP for the
1246 * freq value given to target callback.
1247 * @dev: The devfreq user device. (parent of devfreq)
1248 * @freq: The frequency given to target function
1249 * @flags: Flags handed from devfreq framework.
1251 * Locking: This function must be called under rcu_read_lock(). opp is a rcu
1252 * protected pointer. The reason for the same is that the opp pointer which is
1253 * returned will remain valid for use with opp_get_{voltage, freq} only while
1254 * under the locked area. The pointer returned must be used prior to unlocking
1255 * with rcu_read_unlock() to maintain the integrity of the pointer.
1257 struct dev_pm_opp
*devfreq_recommended_opp(struct device
*dev
,
1258 unsigned long *freq
,
1261 struct dev_pm_opp
*opp
;
1263 if (flags
& DEVFREQ_FLAG_LEAST_UPPER_BOUND
) {
1264 /* The freq is an upper bound. opp should be lower */
1265 opp
= dev_pm_opp_find_freq_floor(dev
, freq
);
1267 /* If not available, use the closest opp */
1268 if (opp
== ERR_PTR(-ERANGE
))
1269 opp
= dev_pm_opp_find_freq_ceil(dev
, freq
);
1271 /* The freq is an lower bound. opp should be higher */
1272 opp
= dev_pm_opp_find_freq_ceil(dev
, freq
);
1274 /* If not available, use the closest opp */
1275 if (opp
== ERR_PTR(-ERANGE
))
1276 opp
= dev_pm_opp_find_freq_floor(dev
, freq
);
1281 EXPORT_SYMBOL(devfreq_recommended_opp
);
1284 * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1285 * for any changes in the OPP availability
1287 * @dev: The devfreq user device. (parent of devfreq)
1288 * @devfreq: The devfreq object.
1290 int devfreq_register_opp_notifier(struct device
*dev
, struct devfreq
*devfreq
)
1292 struct srcu_notifier_head
*nh
;
1296 nh
= dev_pm_opp_get_notifier(dev
);
1301 ret
= srcu_notifier_chain_register(nh
, &devfreq
->nb
);
1305 EXPORT_SYMBOL(devfreq_register_opp_notifier
);
1308 * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1309 * notified for any changes in the OPP
1310 * availability changes anymore.
1311 * @dev: The devfreq user device. (parent of devfreq)
1312 * @devfreq: The devfreq object.
1314 * At exit() callback of devfreq_dev_profile, this must be included if
1315 * devfreq_recommended_opp is used.
1317 int devfreq_unregister_opp_notifier(struct device
*dev
, struct devfreq
*devfreq
)
1319 struct srcu_notifier_head
*nh
;
1323 nh
= dev_pm_opp_get_notifier(dev
);
1328 ret
= srcu_notifier_chain_unregister(nh
, &devfreq
->nb
);
1332 EXPORT_SYMBOL(devfreq_unregister_opp_notifier
);
1334 static void devm_devfreq_opp_release(struct device
*dev
, void *res
)
1336 devfreq_unregister_opp_notifier(dev
, *(struct devfreq
**)res
);
1340 * devm_ devfreq_register_opp_notifier()
1341 * - Resource-managed devfreq_register_opp_notifier()
1342 * @dev: The devfreq user device. (parent of devfreq)
1343 * @devfreq: The devfreq object.
1345 int devm_devfreq_register_opp_notifier(struct device
*dev
,
1346 struct devfreq
*devfreq
)
1348 struct devfreq
**ptr
;
1351 ptr
= devres_alloc(devm_devfreq_opp_release
, sizeof(*ptr
), GFP_KERNEL
);
1355 ret
= devfreq_register_opp_notifier(dev
, devfreq
);
1362 devres_add(dev
, ptr
);
1366 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier
);
1369 * devm_devfreq_unregister_opp_notifier()
1370 * - Resource-managed devfreq_unregister_opp_notifier()
1371 * @dev: The devfreq user device. (parent of devfreq)
1372 * @devfreq: The devfreq object.
1374 void devm_devfreq_unregister_opp_notifier(struct device
*dev
,
1375 struct devfreq
*devfreq
)
1377 WARN_ON(devres_release(dev
, devm_devfreq_opp_release
,
1378 devm_devfreq_dev_match
, devfreq
));
1380 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier
);
1383 * devfreq_register_notifier() - Register a driver with devfreq
1384 * @devfreq: The devfreq object.
1385 * @nb: The notifier block to register.
1386 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1388 int devfreq_register_notifier(struct devfreq
*devfreq
,
1389 struct notifier_block
*nb
,
1398 case DEVFREQ_TRANSITION_NOTIFIER
:
1399 ret
= srcu_notifier_chain_register(
1400 &devfreq
->transition_notifier_list
, nb
);
1408 EXPORT_SYMBOL(devfreq_register_notifier
);
1411 * devfreq_unregister_notifier() - Unregister a driver with devfreq
1412 * @devfreq: The devfreq object.
1413 * @nb: The notifier block to be unregistered.
1414 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1416 int devfreq_unregister_notifier(struct devfreq
*devfreq
,
1417 struct notifier_block
*nb
,
1426 case DEVFREQ_TRANSITION_NOTIFIER
:
1427 ret
= srcu_notifier_chain_unregister(
1428 &devfreq
->transition_notifier_list
, nb
);
1436 EXPORT_SYMBOL(devfreq_unregister_notifier
);
1438 struct devfreq_notifier_devres
{
1439 struct devfreq
*devfreq
;
1440 struct notifier_block
*nb
;
1444 static void devm_devfreq_notifier_release(struct device
*dev
, void *res
)
1446 struct devfreq_notifier_devres
*this = res
;
1448 devfreq_unregister_notifier(this->devfreq
, this->nb
, this->list
);
1452 * devm_devfreq_register_notifier()
1453 - Resource-managed devfreq_register_notifier()
1454 * @dev: The devfreq user device. (parent of devfreq)
1455 * @devfreq: The devfreq object.
1456 * @nb: The notifier block to be unregistered.
1457 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1459 int devm_devfreq_register_notifier(struct device
*dev
,
1460 struct devfreq
*devfreq
,
1461 struct notifier_block
*nb
,
1464 struct devfreq_notifier_devres
*ptr
;
1467 ptr
= devres_alloc(devm_devfreq_notifier_release
, sizeof(*ptr
),
1472 ret
= devfreq_register_notifier(devfreq
, nb
, list
);
1478 ptr
->devfreq
= devfreq
;
1481 devres_add(dev
, ptr
);
1485 EXPORT_SYMBOL(devm_devfreq_register_notifier
);
1488 * devm_devfreq_unregister_notifier()
1489 - Resource-managed devfreq_unregister_notifier()
1490 * @dev: The devfreq user device. (parent of devfreq)
1491 * @devfreq: The devfreq object.
1492 * @nb: The notifier block to be unregistered.
1493 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1495 void devm_devfreq_unregister_notifier(struct device
*dev
,
1496 struct devfreq
*devfreq
,
1497 struct notifier_block
*nb
,
1500 WARN_ON(devres_release(dev
, devm_devfreq_notifier_release
,
1501 devm_devfreq_dev_match
, devfreq
));
1503 EXPORT_SYMBOL(devm_devfreq_unregister_notifier
);