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/module.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 static int devfreq_update_status(struct devfreq
*devfreq
, unsigned long freq
)
135 int lev
, prev_lev
, ret
= 0;
136 unsigned long cur_time
;
140 prev_lev
= devfreq_get_freq_level(devfreq
, devfreq
->previous_freq
);
146 devfreq
->time_in_state
[prev_lev
] +=
147 cur_time
- devfreq
->last_stat_updated
;
149 lev
= devfreq_get_freq_level(devfreq
, freq
);
155 if (lev
!= prev_lev
) {
156 devfreq
->trans_table
[(prev_lev
*
157 devfreq
->profile
->max_state
) + lev
]++;
158 devfreq
->total_trans
++;
162 devfreq
->last_stat_updated
= cur_time
;
167 * find_devfreq_governor() - find devfreq governor from name
168 * @name: name of the governor
170 * Search the list of devfreq governors and return the matched
171 * governor's pointer. devfreq_list_lock should be held by the caller.
173 static struct devfreq_governor
*find_devfreq_governor(const char *name
)
175 struct devfreq_governor
*tmp_governor
;
177 if (IS_ERR_OR_NULL(name
)) {
178 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__
);
179 return ERR_PTR(-EINVAL
);
181 WARN(!mutex_is_locked(&devfreq_list_lock
),
182 "devfreq_list_lock must be locked.");
184 list_for_each_entry(tmp_governor
, &devfreq_governor_list
, node
) {
185 if (!strncmp(tmp_governor
->name
, name
, DEVFREQ_NAME_LEN
))
189 return ERR_PTR(-ENODEV
);
192 static int devfreq_notify_transition(struct devfreq
*devfreq
,
193 struct devfreq_freqs
*freqs
, unsigned int state
)
199 case DEVFREQ_PRECHANGE
:
200 srcu_notifier_call_chain(&devfreq
->transition_notifier_list
,
201 DEVFREQ_PRECHANGE
, freqs
);
204 case DEVFREQ_POSTCHANGE
:
205 srcu_notifier_call_chain(&devfreq
->transition_notifier_list
,
206 DEVFREQ_POSTCHANGE
, freqs
);
215 /* Load monitoring helper functions for governors use */
218 * update_devfreq() - Reevaluate the device and configure frequency.
219 * @devfreq: the devfreq instance.
221 * Note: Lock devfreq->lock before calling update_devfreq
222 * This function is exported for governors.
224 int update_devfreq(struct devfreq
*devfreq
)
226 struct devfreq_freqs freqs
;
227 unsigned long freq
, cur_freq
;
231 if (!mutex_is_locked(&devfreq
->lock
)) {
232 WARN(true, "devfreq->lock must be locked by the caller.\n");
236 if (!devfreq
->governor
)
239 /* Reevaluate the proper frequency */
240 err
= devfreq
->governor
->get_target_freq(devfreq
, &freq
);
245 * Adjust the frequency with user freq and QoS.
247 * List from the highest priority
252 if (devfreq
->min_freq
&& freq
< devfreq
->min_freq
) {
253 freq
= devfreq
->min_freq
;
254 flags
&= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND
; /* Use GLB */
256 if (devfreq
->max_freq
&& freq
> devfreq
->max_freq
) {
257 freq
= devfreq
->max_freq
;
258 flags
|= DEVFREQ_FLAG_LEAST_UPPER_BOUND
; /* Use LUB */
261 if (devfreq
->profile
->get_cur_freq
)
262 devfreq
->profile
->get_cur_freq(devfreq
->dev
.parent
, &cur_freq
);
264 cur_freq
= devfreq
->previous_freq
;
266 freqs
.old
= cur_freq
;
268 devfreq_notify_transition(devfreq
, &freqs
, DEVFREQ_PRECHANGE
);
270 err
= devfreq
->profile
->target(devfreq
->dev
.parent
, &freq
, flags
);
275 devfreq_notify_transition(devfreq
, &freqs
, DEVFREQ_POSTCHANGE
);
277 if (devfreq
->profile
->freq_table
)
278 if (devfreq_update_status(devfreq
, freq
))
279 dev_err(&devfreq
->dev
,
280 "Couldn't update frequency transition information.\n");
282 devfreq
->previous_freq
= freq
;
285 EXPORT_SYMBOL(update_devfreq
);
288 * devfreq_monitor() - Periodically poll devfreq objects.
289 * @work: the work struct used to run devfreq_monitor periodically.
292 static void devfreq_monitor(struct work_struct
*work
)
295 struct devfreq
*devfreq
= container_of(work
,
296 struct devfreq
, work
.work
);
298 mutex_lock(&devfreq
->lock
);
299 err
= update_devfreq(devfreq
);
301 dev_err(&devfreq
->dev
, "dvfs failed with (%d) error\n", err
);
303 queue_delayed_work(devfreq_wq
, &devfreq
->work
,
304 msecs_to_jiffies(devfreq
->profile
->polling_ms
));
305 mutex_unlock(&devfreq
->lock
);
309 * devfreq_monitor_start() - Start load monitoring of devfreq instance
310 * @devfreq: the devfreq instance.
312 * Helper function for starting devfreq device load monitoing. By
313 * default delayed work based monitoring is supported. Function
314 * to be called from governor in response to DEVFREQ_GOV_START
315 * event when device is added to devfreq framework.
317 void devfreq_monitor_start(struct devfreq
*devfreq
)
319 INIT_DEFERRABLE_WORK(&devfreq
->work
, devfreq_monitor
);
320 if (devfreq
->profile
->polling_ms
)
321 queue_delayed_work(devfreq_wq
, &devfreq
->work
,
322 msecs_to_jiffies(devfreq
->profile
->polling_ms
));
324 EXPORT_SYMBOL(devfreq_monitor_start
);
327 * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
328 * @devfreq: the devfreq instance.
330 * Helper function to stop devfreq device load monitoing. Function
331 * to be called from governor in response to DEVFREQ_GOV_STOP
332 * event when device is removed from devfreq framework.
334 void devfreq_monitor_stop(struct devfreq
*devfreq
)
336 cancel_delayed_work_sync(&devfreq
->work
);
338 EXPORT_SYMBOL(devfreq_monitor_stop
);
341 * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
342 * @devfreq: the devfreq instance.
344 * Helper function to suspend devfreq device load monitoing. Function
345 * to be called from governor in response to DEVFREQ_GOV_SUSPEND
346 * event or when polling interval is set to zero.
348 * Note: Though this function is same as devfreq_monitor_stop(),
349 * intentionally kept separate to provide hooks for collecting
350 * transition statistics.
352 void devfreq_monitor_suspend(struct devfreq
*devfreq
)
354 mutex_lock(&devfreq
->lock
);
355 if (devfreq
->stop_polling
) {
356 mutex_unlock(&devfreq
->lock
);
360 devfreq_update_status(devfreq
, devfreq
->previous_freq
);
361 devfreq
->stop_polling
= true;
362 mutex_unlock(&devfreq
->lock
);
363 cancel_delayed_work_sync(&devfreq
->work
);
365 EXPORT_SYMBOL(devfreq_monitor_suspend
);
368 * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
369 * @devfreq: the devfreq instance.
371 * Helper function to resume devfreq device load monitoing. Function
372 * to be called from governor in response to DEVFREQ_GOV_RESUME
373 * event or when polling interval is set to non-zero.
375 void devfreq_monitor_resume(struct devfreq
*devfreq
)
379 mutex_lock(&devfreq
->lock
);
380 if (!devfreq
->stop_polling
)
383 if (!delayed_work_pending(&devfreq
->work
) &&
384 devfreq
->profile
->polling_ms
)
385 queue_delayed_work(devfreq_wq
, &devfreq
->work
,
386 msecs_to_jiffies(devfreq
->profile
->polling_ms
));
388 devfreq
->last_stat_updated
= jiffies
;
389 devfreq
->stop_polling
= false;
391 if (devfreq
->profile
->get_cur_freq
&&
392 !devfreq
->profile
->get_cur_freq(devfreq
->dev
.parent
, &freq
))
393 devfreq
->previous_freq
= freq
;
396 mutex_unlock(&devfreq
->lock
);
398 EXPORT_SYMBOL(devfreq_monitor_resume
);
401 * devfreq_interval_update() - Update device devfreq monitoring interval
402 * @devfreq: the devfreq instance.
403 * @delay: new polling interval to be set.
405 * Helper function to set new load monitoring polling interval. Function
406 * to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
408 void devfreq_interval_update(struct devfreq
*devfreq
, unsigned int *delay
)
410 unsigned int cur_delay
= devfreq
->profile
->polling_ms
;
411 unsigned int new_delay
= *delay
;
413 mutex_lock(&devfreq
->lock
);
414 devfreq
->profile
->polling_ms
= new_delay
;
416 if (devfreq
->stop_polling
)
419 /* if new delay is zero, stop polling */
421 mutex_unlock(&devfreq
->lock
);
422 cancel_delayed_work_sync(&devfreq
->work
);
426 /* if current delay is zero, start polling with new delay */
428 queue_delayed_work(devfreq_wq
, &devfreq
->work
,
429 msecs_to_jiffies(devfreq
->profile
->polling_ms
));
433 /* if current delay is greater than new delay, restart polling */
434 if (cur_delay
> new_delay
) {
435 mutex_unlock(&devfreq
->lock
);
436 cancel_delayed_work_sync(&devfreq
->work
);
437 mutex_lock(&devfreq
->lock
);
438 if (!devfreq
->stop_polling
)
439 queue_delayed_work(devfreq_wq
, &devfreq
->work
,
440 msecs_to_jiffies(devfreq
->profile
->polling_ms
));
443 mutex_unlock(&devfreq
->lock
);
445 EXPORT_SYMBOL(devfreq_interval_update
);
448 * devfreq_notifier_call() - Notify that the device frequency requirements
449 * has been changed out of devfreq framework.
450 * @nb: the notifier_block (supposed to be devfreq->nb)
454 * Called by a notifier that uses devfreq->nb.
456 static int devfreq_notifier_call(struct notifier_block
*nb
, unsigned long type
,
459 struct devfreq
*devfreq
= container_of(nb
, struct devfreq
, nb
);
462 mutex_lock(&devfreq
->lock
);
463 ret
= update_devfreq(devfreq
);
464 mutex_unlock(&devfreq
->lock
);
470 * _remove_devfreq() - Remove devfreq from the list and release its resources.
471 * @devfreq: the devfreq struct
473 static void _remove_devfreq(struct devfreq
*devfreq
)
475 mutex_lock(&devfreq_list_lock
);
476 if (IS_ERR(find_device_devfreq(devfreq
->dev
.parent
))) {
477 mutex_unlock(&devfreq_list_lock
);
478 dev_warn(&devfreq
->dev
, "releasing devfreq which doesn't exist\n");
481 list_del(&devfreq
->node
);
482 mutex_unlock(&devfreq_list_lock
);
484 if (devfreq
->governor
)
485 devfreq
->governor
->event_handler(devfreq
,
486 DEVFREQ_GOV_STOP
, NULL
);
488 if (devfreq
->profile
->exit
)
489 devfreq
->profile
->exit(devfreq
->dev
.parent
);
491 mutex_destroy(&devfreq
->lock
);
496 * devfreq_dev_release() - Callback for struct device to release the device.
497 * @dev: the devfreq device
499 * This calls _remove_devfreq() if _remove_devfreq() is not called.
501 static void devfreq_dev_release(struct device
*dev
)
503 struct devfreq
*devfreq
= to_devfreq(dev
);
505 _remove_devfreq(devfreq
);
509 * devfreq_add_device() - Add devfreq feature to the device
510 * @dev: the device to add devfreq feature.
511 * @profile: device-specific profile to run devfreq.
512 * @governor_name: name of the policy to choose frequency.
513 * @data: private data for the governor. The devfreq framework does not
516 struct devfreq
*devfreq_add_device(struct device
*dev
,
517 struct devfreq_dev_profile
*profile
,
518 const char *governor_name
,
521 struct devfreq
*devfreq
;
522 struct devfreq_governor
*governor
;
525 if (!dev
|| !profile
|| !governor_name
) {
526 dev_err(dev
, "%s: Invalid parameters.\n", __func__
);
527 return ERR_PTR(-EINVAL
);
530 mutex_lock(&devfreq_list_lock
);
531 devfreq
= find_device_devfreq(dev
);
532 mutex_unlock(&devfreq_list_lock
);
533 if (!IS_ERR(devfreq
)) {
534 dev_err(dev
, "%s: Unable to create devfreq for the device. It already has one.\n", __func__
);
539 devfreq
= kzalloc(sizeof(struct devfreq
), GFP_KERNEL
);
541 dev_err(dev
, "%s: Unable to create devfreq for the device\n",
547 mutex_init(&devfreq
->lock
);
548 mutex_lock(&devfreq
->lock
);
549 devfreq
->dev
.parent
= dev
;
550 devfreq
->dev
.class = devfreq_class
;
551 devfreq
->dev
.release
= devfreq_dev_release
;
552 devfreq
->profile
= profile
;
553 strncpy(devfreq
->governor_name
, governor_name
, DEVFREQ_NAME_LEN
);
554 devfreq
->previous_freq
= profile
->initial_freq
;
555 devfreq
->data
= data
;
556 devfreq
->nb
.notifier_call
= devfreq_notifier_call
;
558 if (!devfreq
->profile
->max_state
&& !devfreq
->profile
->freq_table
) {
559 mutex_unlock(&devfreq
->lock
);
560 devfreq_set_freq_table(devfreq
);
561 mutex_lock(&devfreq
->lock
);
564 devfreq
->trans_table
= devm_kzalloc(dev
, sizeof(unsigned int) *
565 devfreq
->profile
->max_state
*
566 devfreq
->profile
->max_state
,
568 devfreq
->time_in_state
= devm_kzalloc(dev
, sizeof(unsigned long) *
569 devfreq
->profile
->max_state
,
571 devfreq
->last_stat_updated
= jiffies
;
573 dev_set_name(&devfreq
->dev
, "%s", dev_name(dev
));
574 err
= device_register(&devfreq
->dev
);
576 put_device(&devfreq
->dev
);
577 mutex_unlock(&devfreq
->lock
);
581 srcu_init_notifier_head(&devfreq
->transition_notifier_list
);
583 mutex_unlock(&devfreq
->lock
);
585 mutex_lock(&devfreq_list_lock
);
586 list_add(&devfreq
->node
, &devfreq_list
);
588 governor
= find_devfreq_governor(devfreq
->governor_name
);
589 if (!IS_ERR(governor
))
590 devfreq
->governor
= governor
;
591 if (devfreq
->governor
)
592 err
= devfreq
->governor
->event_handler(devfreq
,
593 DEVFREQ_GOV_START
, NULL
);
594 mutex_unlock(&devfreq_list_lock
);
596 dev_err(dev
, "%s: Unable to start governor for the device\n",
604 list_del(&devfreq
->node
);
605 device_unregister(&devfreq
->dev
);
610 EXPORT_SYMBOL(devfreq_add_device
);
613 * devfreq_remove_device() - Remove devfreq feature from a device.
614 * @devfreq: the devfreq instance to be removed
616 * The opposite of devfreq_add_device().
618 int devfreq_remove_device(struct devfreq
*devfreq
)
623 device_unregister(&devfreq
->dev
);
624 put_device(&devfreq
->dev
);
628 EXPORT_SYMBOL(devfreq_remove_device
);
630 static int devm_devfreq_dev_match(struct device
*dev
, void *res
, void *data
)
632 struct devfreq
**r
= res
;
634 if (WARN_ON(!r
|| !*r
))
640 static void devm_devfreq_dev_release(struct device
*dev
, void *res
)
642 devfreq_remove_device(*(struct devfreq
**)res
);
646 * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
647 * @dev: the device to add devfreq feature.
648 * @profile: device-specific profile to run devfreq.
649 * @governor_name: name of the policy to choose frequency.
650 * @data: private data for the governor. The devfreq framework does not
653 * This function manages automatically the memory of devfreq device using device
654 * resource management and simplify the free operation for memory of devfreq
657 struct devfreq
*devm_devfreq_add_device(struct device
*dev
,
658 struct devfreq_dev_profile
*profile
,
659 const char *governor_name
,
662 struct devfreq
**ptr
, *devfreq
;
664 ptr
= devres_alloc(devm_devfreq_dev_release
, sizeof(*ptr
), GFP_KERNEL
);
666 return ERR_PTR(-ENOMEM
);
668 devfreq
= devfreq_add_device(dev
, profile
, governor_name
, data
);
669 if (IS_ERR(devfreq
)) {
671 return ERR_PTR(-ENOMEM
);
675 devres_add(dev
, ptr
);
679 EXPORT_SYMBOL(devm_devfreq_add_device
);
683 * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
684 * @dev - instance to the given device
685 * @index - index into list of devfreq
687 * return the instance of devfreq device
689 struct devfreq
*devfreq_get_devfreq_by_phandle(struct device
*dev
, int index
)
691 struct device_node
*node
;
692 struct devfreq
*devfreq
;
695 return ERR_PTR(-EINVAL
);
698 return ERR_PTR(-EINVAL
);
700 node
= of_parse_phandle(dev
->of_node
, "devfreq", index
);
702 return ERR_PTR(-ENODEV
);
704 mutex_lock(&devfreq_list_lock
);
705 list_for_each_entry(devfreq
, &devfreq_list
, node
) {
706 if (devfreq
->dev
.parent
707 && devfreq
->dev
.parent
->of_node
== node
) {
708 mutex_unlock(&devfreq_list_lock
);
712 mutex_unlock(&devfreq_list_lock
);
714 return ERR_PTR(-EPROBE_DEFER
);
717 struct devfreq
*devfreq_get_devfreq_by_phandle(struct device
*dev
, int index
)
719 return ERR_PTR(-ENODEV
);
721 #endif /* CONFIG_OF */
722 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle
);
725 * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
726 * @dev: the device to add devfreq feature.
727 * @devfreq: the devfreq instance to be removed
729 void devm_devfreq_remove_device(struct device
*dev
, struct devfreq
*devfreq
)
731 WARN_ON(devres_release(dev
, devm_devfreq_dev_release
,
732 devm_devfreq_dev_match
, devfreq
));
734 EXPORT_SYMBOL(devm_devfreq_remove_device
);
737 * devfreq_suspend_device() - Suspend devfreq of a device.
738 * @devfreq: the devfreq instance to be suspended
740 * This function is intended to be called by the pm callbacks
741 * (e.g., runtime_suspend, suspend) of the device driver that
744 int devfreq_suspend_device(struct devfreq
*devfreq
)
749 if (!devfreq
->governor
)
752 return devfreq
->governor
->event_handler(devfreq
,
753 DEVFREQ_GOV_SUSPEND
, NULL
);
755 EXPORT_SYMBOL(devfreq_suspend_device
);
758 * devfreq_resume_device() - Resume devfreq of a device.
759 * @devfreq: the devfreq instance to be resumed
761 * This function is intended to be called by the pm callbacks
762 * (e.g., runtime_resume, resume) of the device driver that
765 int devfreq_resume_device(struct devfreq
*devfreq
)
770 if (!devfreq
->governor
)
773 return devfreq
->governor
->event_handler(devfreq
,
774 DEVFREQ_GOV_RESUME
, NULL
);
776 EXPORT_SYMBOL(devfreq_resume_device
);
779 * devfreq_add_governor() - Add devfreq governor
780 * @governor: the devfreq governor to be added
782 int devfreq_add_governor(struct devfreq_governor
*governor
)
784 struct devfreq_governor
*g
;
785 struct devfreq
*devfreq
;
789 pr_err("%s: Invalid parameters.\n", __func__
);
793 mutex_lock(&devfreq_list_lock
);
794 g
= find_devfreq_governor(governor
->name
);
796 pr_err("%s: governor %s already registered\n", __func__
,
802 list_add(&governor
->node
, &devfreq_governor_list
);
804 list_for_each_entry(devfreq
, &devfreq_list
, node
) {
806 struct device
*dev
= devfreq
->dev
.parent
;
808 if (!strncmp(devfreq
->governor_name
, governor
->name
,
810 /* The following should never occur */
811 if (devfreq
->governor
) {
813 "%s: Governor %s already present\n",
814 __func__
, devfreq
->governor
->name
);
815 ret
= devfreq
->governor
->event_handler(devfreq
,
816 DEVFREQ_GOV_STOP
, NULL
);
819 "%s: Governor %s stop = %d\n",
821 devfreq
->governor
->name
, ret
);
825 devfreq
->governor
= governor
;
826 ret
= devfreq
->governor
->event_handler(devfreq
,
827 DEVFREQ_GOV_START
, NULL
);
829 dev_warn(dev
, "%s: Governor %s start=%d\n",
830 __func__
, devfreq
->governor
->name
,
837 mutex_unlock(&devfreq_list_lock
);
841 EXPORT_SYMBOL(devfreq_add_governor
);
844 * devfreq_remove_device() - Remove devfreq feature from a device.
845 * @governor: the devfreq governor to be removed
847 int devfreq_remove_governor(struct devfreq_governor
*governor
)
849 struct devfreq_governor
*g
;
850 struct devfreq
*devfreq
;
854 pr_err("%s: Invalid parameters.\n", __func__
);
858 mutex_lock(&devfreq_list_lock
);
859 g
= find_devfreq_governor(governor
->name
);
861 pr_err("%s: governor %s not registered\n", __func__
,
866 list_for_each_entry(devfreq
, &devfreq_list
, node
) {
868 struct device
*dev
= devfreq
->dev
.parent
;
870 if (!strncmp(devfreq
->governor_name
, governor
->name
,
872 /* we should have a devfreq governor! */
873 if (!devfreq
->governor
) {
874 dev_warn(dev
, "%s: Governor %s NOT present\n",
875 __func__
, governor
->name
);
879 ret
= devfreq
->governor
->event_handler(devfreq
,
880 DEVFREQ_GOV_STOP
, NULL
);
882 dev_warn(dev
, "%s: Governor %s stop=%d\n",
883 __func__
, devfreq
->governor
->name
,
886 devfreq
->governor
= NULL
;
890 list_del(&governor
->node
);
892 mutex_unlock(&devfreq_list_lock
);
896 EXPORT_SYMBOL(devfreq_remove_governor
);
898 static ssize_t
governor_show(struct device
*dev
,
899 struct device_attribute
*attr
, char *buf
)
901 if (!to_devfreq(dev
)->governor
)
904 return sprintf(buf
, "%s\n", to_devfreq(dev
)->governor
->name
);
907 static ssize_t
governor_store(struct device
*dev
, struct device_attribute
*attr
,
908 const char *buf
, size_t count
)
910 struct devfreq
*df
= to_devfreq(dev
);
912 char str_governor
[DEVFREQ_NAME_LEN
+ 1];
913 struct devfreq_governor
*governor
;
915 ret
= sscanf(buf
, "%" __stringify(DEVFREQ_NAME_LEN
) "s", str_governor
);
919 mutex_lock(&devfreq_list_lock
);
920 governor
= find_devfreq_governor(str_governor
);
921 if (IS_ERR(governor
)) {
922 ret
= PTR_ERR(governor
);
925 if (df
->governor
== governor
) {
931 ret
= df
->governor
->event_handler(df
, DEVFREQ_GOV_STOP
, NULL
);
933 dev_warn(dev
, "%s: Governor %s not stopped(%d)\n",
934 __func__
, df
->governor
->name
, ret
);
938 df
->governor
= governor
;
939 strncpy(df
->governor_name
, governor
->name
, DEVFREQ_NAME_LEN
);
940 ret
= df
->governor
->event_handler(df
, DEVFREQ_GOV_START
, NULL
);
942 dev_warn(dev
, "%s: Governor %s not started(%d)\n",
943 __func__
, df
->governor
->name
, ret
);
945 mutex_unlock(&devfreq_list_lock
);
951 static DEVICE_ATTR_RW(governor
);
953 static ssize_t
available_governors_show(struct device
*d
,
954 struct device_attribute
*attr
,
957 struct devfreq_governor
*tmp_governor
;
960 mutex_lock(&devfreq_list_lock
);
961 list_for_each_entry(tmp_governor
, &devfreq_governor_list
, node
)
962 count
+= scnprintf(&buf
[count
], (PAGE_SIZE
- count
- 2),
963 "%s ", tmp_governor
->name
);
964 mutex_unlock(&devfreq_list_lock
);
966 /* Truncate the trailing space */
970 count
+= sprintf(&buf
[count
], "\n");
974 static DEVICE_ATTR_RO(available_governors
);
976 static ssize_t
cur_freq_show(struct device
*dev
, struct device_attribute
*attr
,
980 struct devfreq
*devfreq
= to_devfreq(dev
);
982 if (devfreq
->profile
->get_cur_freq
&&
983 !devfreq
->profile
->get_cur_freq(devfreq
->dev
.parent
, &freq
))
984 return sprintf(buf
, "%lu\n", freq
);
986 return sprintf(buf
, "%lu\n", devfreq
->previous_freq
);
988 static DEVICE_ATTR_RO(cur_freq
);
990 static ssize_t
target_freq_show(struct device
*dev
,
991 struct device_attribute
*attr
, char *buf
)
993 return sprintf(buf
, "%lu\n", to_devfreq(dev
)->previous_freq
);
995 static DEVICE_ATTR_RO(target_freq
);
997 static ssize_t
polling_interval_show(struct device
*dev
,
998 struct device_attribute
*attr
, char *buf
)
1000 return sprintf(buf
, "%d\n", to_devfreq(dev
)->profile
->polling_ms
);
1003 static ssize_t
polling_interval_store(struct device
*dev
,
1004 struct device_attribute
*attr
,
1005 const char *buf
, size_t count
)
1007 struct devfreq
*df
= to_devfreq(dev
);
1014 ret
= sscanf(buf
, "%u", &value
);
1018 df
->governor
->event_handler(df
, DEVFREQ_GOV_INTERVAL
, &value
);
1023 static DEVICE_ATTR_RW(polling_interval
);
1025 static ssize_t
min_freq_store(struct device
*dev
, struct device_attribute
*attr
,
1026 const char *buf
, size_t count
)
1028 struct devfreq
*df
= to_devfreq(dev
);
1029 unsigned long value
;
1033 ret
= sscanf(buf
, "%lu", &value
);
1037 mutex_lock(&df
->lock
);
1039 if (value
&& max
&& value
> max
) {
1044 df
->min_freq
= value
;
1048 mutex_unlock(&df
->lock
);
1052 static ssize_t
max_freq_store(struct device
*dev
, struct device_attribute
*attr
,
1053 const char *buf
, size_t count
)
1055 struct devfreq
*df
= to_devfreq(dev
);
1056 unsigned long value
;
1060 ret
= sscanf(buf
, "%lu", &value
);
1064 mutex_lock(&df
->lock
);
1066 if (value
&& min
&& value
< min
) {
1071 df
->max_freq
= value
;
1075 mutex_unlock(&df
->lock
);
1079 #define show_one(name) \
1080 static ssize_t name##_show \
1081 (struct device *dev, struct device_attribute *attr, char *buf) \
1083 return sprintf(buf, "%lu\n", to_devfreq(dev)->name); \
1088 static DEVICE_ATTR_RW(min_freq
);
1089 static DEVICE_ATTR_RW(max_freq
);
1091 static ssize_t
available_frequencies_show(struct device
*d
,
1092 struct device_attribute
*attr
,
1095 struct devfreq
*df
= to_devfreq(d
);
1096 struct device
*dev
= df
->dev
.parent
;
1097 struct dev_pm_opp
*opp
;
1099 unsigned long freq
= 0;
1103 opp
= dev_pm_opp_find_freq_ceil(dev
, &freq
);
1107 count
+= scnprintf(&buf
[count
], (PAGE_SIZE
- count
- 2),
1113 /* Truncate the trailing space */
1117 count
+= sprintf(&buf
[count
], "\n");
1121 static DEVICE_ATTR_RO(available_frequencies
);
1123 static ssize_t
trans_stat_show(struct device
*dev
,
1124 struct device_attribute
*attr
, char *buf
)
1126 struct devfreq
*devfreq
= to_devfreq(dev
);
1129 unsigned int max_state
= devfreq
->profile
->max_state
;
1131 if (!devfreq
->stop_polling
&&
1132 devfreq_update_status(devfreq
, devfreq
->previous_freq
))
1135 return sprintf(buf
, "Not Supported.\n");
1137 len
= sprintf(buf
, " From : To\n");
1138 len
+= sprintf(buf
+ len
, " :");
1139 for (i
= 0; i
< max_state
; i
++)
1140 len
+= sprintf(buf
+ len
, "%10lu",
1141 devfreq
->profile
->freq_table
[i
]);
1143 len
+= sprintf(buf
+ len
, " time(ms)\n");
1145 for (i
= 0; i
< max_state
; i
++) {
1146 if (devfreq
->profile
->freq_table
[i
]
1147 == devfreq
->previous_freq
) {
1148 len
+= sprintf(buf
+ len
, "*");
1150 len
+= sprintf(buf
+ len
, " ");
1152 len
+= sprintf(buf
+ len
, "%10lu:",
1153 devfreq
->profile
->freq_table
[i
]);
1154 for (j
= 0; j
< max_state
; j
++)
1155 len
+= sprintf(buf
+ len
, "%10u",
1156 devfreq
->trans_table
[(i
* max_state
) + j
]);
1157 len
+= sprintf(buf
+ len
, "%10u\n",
1158 jiffies_to_msecs(devfreq
->time_in_state
[i
]));
1161 len
+= sprintf(buf
+ len
, "Total transition : %u\n",
1162 devfreq
->total_trans
);
1165 static DEVICE_ATTR_RO(trans_stat
);
1167 static struct attribute
*devfreq_attrs
[] = {
1168 &dev_attr_governor
.attr
,
1169 &dev_attr_available_governors
.attr
,
1170 &dev_attr_cur_freq
.attr
,
1171 &dev_attr_available_frequencies
.attr
,
1172 &dev_attr_target_freq
.attr
,
1173 &dev_attr_polling_interval
.attr
,
1174 &dev_attr_min_freq
.attr
,
1175 &dev_attr_max_freq
.attr
,
1176 &dev_attr_trans_stat
.attr
,
1179 ATTRIBUTE_GROUPS(devfreq
);
1181 static int __init
devfreq_init(void)
1183 devfreq_class
= class_create(THIS_MODULE
, "devfreq");
1184 if (IS_ERR(devfreq_class
)) {
1185 pr_err("%s: couldn't create class\n", __FILE__
);
1186 return PTR_ERR(devfreq_class
);
1189 devfreq_wq
= create_freezable_workqueue("devfreq_wq");
1191 class_destroy(devfreq_class
);
1192 pr_err("%s: couldn't create workqueue\n", __FILE__
);
1195 devfreq_class
->dev_groups
= devfreq_groups
;
1199 subsys_initcall(devfreq_init
);
1201 static void __exit
devfreq_exit(void)
1203 class_destroy(devfreq_class
);
1204 destroy_workqueue(devfreq_wq
);
1206 module_exit(devfreq_exit
);
1209 * The followings are helper functions for devfreq user device drivers with
1214 * devfreq_recommended_opp() - Helper function to get proper OPP for the
1215 * freq value given to target callback.
1216 * @dev: The devfreq user device. (parent of devfreq)
1217 * @freq: The frequency given to target function
1218 * @flags: Flags handed from devfreq framework.
1220 * Locking: This function must be called under rcu_read_lock(). opp is a rcu
1221 * protected pointer. The reason for the same is that the opp pointer which is
1222 * returned will remain valid for use with opp_get_{voltage, freq} only while
1223 * under the locked area. The pointer returned must be used prior to unlocking
1224 * with rcu_read_unlock() to maintain the integrity of the pointer.
1226 struct dev_pm_opp
*devfreq_recommended_opp(struct device
*dev
,
1227 unsigned long *freq
,
1230 struct dev_pm_opp
*opp
;
1232 if (flags
& DEVFREQ_FLAG_LEAST_UPPER_BOUND
) {
1233 /* The freq is an upper bound. opp should be lower */
1234 opp
= dev_pm_opp_find_freq_floor(dev
, freq
);
1236 /* If not available, use the closest opp */
1237 if (opp
== ERR_PTR(-ERANGE
))
1238 opp
= dev_pm_opp_find_freq_ceil(dev
, freq
);
1240 /* The freq is an lower bound. opp should be higher */
1241 opp
= dev_pm_opp_find_freq_ceil(dev
, freq
);
1243 /* If not available, use the closest opp */
1244 if (opp
== ERR_PTR(-ERANGE
))
1245 opp
= dev_pm_opp_find_freq_floor(dev
, freq
);
1250 EXPORT_SYMBOL(devfreq_recommended_opp
);
1253 * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1254 * for any changes in the OPP availability
1256 * @dev: The devfreq user device. (parent of devfreq)
1257 * @devfreq: The devfreq object.
1259 int devfreq_register_opp_notifier(struct device
*dev
, struct devfreq
*devfreq
)
1261 struct srcu_notifier_head
*nh
;
1265 nh
= dev_pm_opp_get_notifier(dev
);
1270 ret
= srcu_notifier_chain_register(nh
, &devfreq
->nb
);
1274 EXPORT_SYMBOL(devfreq_register_opp_notifier
);
1277 * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1278 * notified for any changes in the OPP
1279 * availability changes anymore.
1280 * @dev: The devfreq user device. (parent of devfreq)
1281 * @devfreq: The devfreq object.
1283 * At exit() callback of devfreq_dev_profile, this must be included if
1284 * devfreq_recommended_opp is used.
1286 int devfreq_unregister_opp_notifier(struct device
*dev
, struct devfreq
*devfreq
)
1288 struct srcu_notifier_head
*nh
;
1292 nh
= dev_pm_opp_get_notifier(dev
);
1297 ret
= srcu_notifier_chain_unregister(nh
, &devfreq
->nb
);
1301 EXPORT_SYMBOL(devfreq_unregister_opp_notifier
);
1303 static void devm_devfreq_opp_release(struct device
*dev
, void *res
)
1305 devfreq_unregister_opp_notifier(dev
, *(struct devfreq
**)res
);
1309 * devm_ devfreq_register_opp_notifier()
1310 * - Resource-managed devfreq_register_opp_notifier()
1311 * @dev: The devfreq user device. (parent of devfreq)
1312 * @devfreq: The devfreq object.
1314 int devm_devfreq_register_opp_notifier(struct device
*dev
,
1315 struct devfreq
*devfreq
)
1317 struct devfreq
**ptr
;
1320 ptr
= devres_alloc(devm_devfreq_opp_release
, sizeof(*ptr
), GFP_KERNEL
);
1324 ret
= devfreq_register_opp_notifier(dev
, devfreq
);
1331 devres_add(dev
, ptr
);
1335 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier
);
1338 * devm_devfreq_unregister_opp_notifier()
1339 * - Resource-managed devfreq_unregister_opp_notifier()
1340 * @dev: The devfreq user device. (parent of devfreq)
1341 * @devfreq: The devfreq object.
1343 void devm_devfreq_unregister_opp_notifier(struct device
*dev
,
1344 struct devfreq
*devfreq
)
1346 WARN_ON(devres_release(dev
, devm_devfreq_opp_release
,
1347 devm_devfreq_dev_match
, devfreq
));
1349 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier
);
1352 * devfreq_register_notifier() - Register a driver with devfreq
1353 * @devfreq: The devfreq object.
1354 * @nb: The notifier block to register.
1355 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1357 int devfreq_register_notifier(struct devfreq
*devfreq
,
1358 struct notifier_block
*nb
,
1367 case DEVFREQ_TRANSITION_NOTIFIER
:
1368 ret
= srcu_notifier_chain_register(
1369 &devfreq
->transition_notifier_list
, nb
);
1377 EXPORT_SYMBOL(devfreq_register_notifier
);
1380 * devfreq_unregister_notifier() - Unregister a driver with devfreq
1381 * @devfreq: The devfreq object.
1382 * @nb: The notifier block to be unregistered.
1383 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1385 int devfreq_unregister_notifier(struct devfreq
*devfreq
,
1386 struct notifier_block
*nb
,
1395 case DEVFREQ_TRANSITION_NOTIFIER
:
1396 ret
= srcu_notifier_chain_unregister(
1397 &devfreq
->transition_notifier_list
, nb
);
1405 EXPORT_SYMBOL(devfreq_unregister_notifier
);
1407 struct devfreq_notifier_devres
{
1408 struct devfreq
*devfreq
;
1409 struct notifier_block
*nb
;
1413 static void devm_devfreq_notifier_release(struct device
*dev
, void *res
)
1415 struct devfreq_notifier_devres
*this = res
;
1417 devfreq_unregister_notifier(this->devfreq
, this->nb
, this->list
);
1421 * devm_devfreq_register_notifier()
1422 - Resource-managed devfreq_register_notifier()
1423 * @dev: The devfreq user device. (parent of devfreq)
1424 * @devfreq: The devfreq object.
1425 * @nb: The notifier block to be unregistered.
1426 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1428 int devm_devfreq_register_notifier(struct device
*dev
,
1429 struct devfreq
*devfreq
,
1430 struct notifier_block
*nb
,
1433 struct devfreq_notifier_devres
*ptr
;
1436 ptr
= devres_alloc(devm_devfreq_notifier_release
, sizeof(*ptr
),
1441 ret
= devfreq_register_notifier(devfreq
, nb
, list
);
1447 ptr
->devfreq
= devfreq
;
1450 devres_add(dev
, ptr
);
1454 EXPORT_SYMBOL(devm_devfreq_register_notifier
);
1457 * devm_devfreq_unregister_notifier()
1458 - Resource-managed devfreq_unregister_notifier()
1459 * @dev: The devfreq user device. (parent of devfreq)
1460 * @devfreq: The devfreq object.
1461 * @nb: The notifier block to be unregistered.
1462 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1464 void devm_devfreq_unregister_notifier(struct device
*dev
,
1465 struct devfreq
*devfreq
,
1466 struct notifier_block
*nb
,
1469 WARN_ON(devres_release(dev
, devm_devfreq_notifier_release
,
1470 devm_devfreq_dev_match
, devfreq
));
1472 EXPORT_SYMBOL(devm_devfreq_unregister_notifier
);
1474 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
1475 MODULE_DESCRIPTION("devfreq class support");
1476 MODULE_LICENSE("GPL");