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 static 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
;
171 * find_devfreq_governor() - find devfreq governor from name
172 * @name: name of the governor
174 * Search the list of devfreq governors and return the matched
175 * governor's pointer. devfreq_list_lock should be held by the caller.
177 static struct devfreq_governor
*find_devfreq_governor(const char *name
)
179 struct devfreq_governor
*tmp_governor
;
181 if (IS_ERR_OR_NULL(name
)) {
182 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__
);
183 return ERR_PTR(-EINVAL
);
185 WARN(!mutex_is_locked(&devfreq_list_lock
),
186 "devfreq_list_lock must be locked.");
188 list_for_each_entry(tmp_governor
, &devfreq_governor_list
, node
) {
189 if (!strncmp(tmp_governor
->name
, name
, DEVFREQ_NAME_LEN
))
193 return ERR_PTR(-ENODEV
);
196 static int devfreq_notify_transition(struct devfreq
*devfreq
,
197 struct devfreq_freqs
*freqs
, unsigned int state
)
203 case DEVFREQ_PRECHANGE
:
204 srcu_notifier_call_chain(&devfreq
->transition_notifier_list
,
205 DEVFREQ_PRECHANGE
, freqs
);
208 case DEVFREQ_POSTCHANGE
:
209 srcu_notifier_call_chain(&devfreq
->transition_notifier_list
,
210 DEVFREQ_POSTCHANGE
, freqs
);
219 /* Load monitoring helper functions for governors use */
222 * update_devfreq() - Reevaluate the device and configure frequency.
223 * @devfreq: the devfreq instance.
225 * Note: Lock devfreq->lock before calling update_devfreq
226 * This function is exported for governors.
228 int update_devfreq(struct devfreq
*devfreq
)
230 struct devfreq_freqs freqs
;
231 unsigned long freq
, cur_freq
;
235 if (!mutex_is_locked(&devfreq
->lock
)) {
236 WARN(true, "devfreq->lock must be locked by the caller.\n");
240 if (!devfreq
->governor
)
243 /* Reevaluate the proper frequency */
244 err
= devfreq
->governor
->get_target_freq(devfreq
, &freq
);
249 * Adjust the frequency with user freq and QoS.
251 * List from the highest priority
256 if (devfreq
->min_freq
&& freq
< devfreq
->min_freq
) {
257 freq
= devfreq
->min_freq
;
258 flags
&= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND
; /* Use GLB */
260 if (devfreq
->max_freq
&& freq
> devfreq
->max_freq
) {
261 freq
= devfreq
->max_freq
;
262 flags
|= DEVFREQ_FLAG_LEAST_UPPER_BOUND
; /* Use LUB */
265 if (devfreq
->profile
->get_cur_freq
)
266 devfreq
->profile
->get_cur_freq(devfreq
->dev
.parent
, &cur_freq
);
268 cur_freq
= devfreq
->previous_freq
;
270 freqs
.old
= cur_freq
;
272 devfreq_notify_transition(devfreq
, &freqs
, DEVFREQ_PRECHANGE
);
274 err
= devfreq
->profile
->target(devfreq
->dev
.parent
, &freq
, flags
);
276 freqs
.new = cur_freq
;
277 devfreq_notify_transition(devfreq
, &freqs
, DEVFREQ_POSTCHANGE
);
282 devfreq_notify_transition(devfreq
, &freqs
, DEVFREQ_POSTCHANGE
);
284 if (devfreq
->profile
->freq_table
)
285 if (devfreq_update_status(devfreq
, freq
))
286 dev_err(&devfreq
->dev
,
287 "Couldn't update frequency transition information.\n");
289 devfreq
->previous_freq
= freq
;
292 EXPORT_SYMBOL(update_devfreq
);
295 * devfreq_monitor() - Periodically poll devfreq objects.
296 * @work: the work struct used to run devfreq_monitor periodically.
299 static void devfreq_monitor(struct work_struct
*work
)
302 struct devfreq
*devfreq
= container_of(work
,
303 struct devfreq
, work
.work
);
305 mutex_lock(&devfreq
->lock
);
306 err
= update_devfreq(devfreq
);
308 dev_err(&devfreq
->dev
, "dvfs failed with (%d) error\n", err
);
310 queue_delayed_work(devfreq_wq
, &devfreq
->work
,
311 msecs_to_jiffies(devfreq
->profile
->polling_ms
));
312 mutex_unlock(&devfreq
->lock
);
316 * devfreq_monitor_start() - Start load monitoring of devfreq instance
317 * @devfreq: the devfreq instance.
319 * Helper function for starting devfreq device load monitoing. By
320 * default delayed work based monitoring is supported. Function
321 * to be called from governor in response to DEVFREQ_GOV_START
322 * event when device is added to devfreq framework.
324 void devfreq_monitor_start(struct devfreq
*devfreq
)
326 INIT_DEFERRABLE_WORK(&devfreq
->work
, devfreq_monitor
);
327 if (devfreq
->profile
->polling_ms
)
328 queue_delayed_work(devfreq_wq
, &devfreq
->work
,
329 msecs_to_jiffies(devfreq
->profile
->polling_ms
));
331 EXPORT_SYMBOL(devfreq_monitor_start
);
334 * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
335 * @devfreq: the devfreq instance.
337 * Helper function to stop devfreq device load monitoing. Function
338 * to be called from governor in response to DEVFREQ_GOV_STOP
339 * event when device is removed from devfreq framework.
341 void devfreq_monitor_stop(struct devfreq
*devfreq
)
343 cancel_delayed_work_sync(&devfreq
->work
);
345 EXPORT_SYMBOL(devfreq_monitor_stop
);
348 * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
349 * @devfreq: the devfreq instance.
351 * Helper function to suspend devfreq device load monitoing. Function
352 * to be called from governor in response to DEVFREQ_GOV_SUSPEND
353 * event or when polling interval is set to zero.
355 * Note: Though this function is same as devfreq_monitor_stop(),
356 * intentionally kept separate to provide hooks for collecting
357 * transition statistics.
359 void devfreq_monitor_suspend(struct devfreq
*devfreq
)
361 mutex_lock(&devfreq
->lock
);
362 if (devfreq
->stop_polling
) {
363 mutex_unlock(&devfreq
->lock
);
367 devfreq_update_status(devfreq
, devfreq
->previous_freq
);
368 devfreq
->stop_polling
= true;
369 mutex_unlock(&devfreq
->lock
);
370 cancel_delayed_work_sync(&devfreq
->work
);
372 EXPORT_SYMBOL(devfreq_monitor_suspend
);
375 * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
376 * @devfreq: the devfreq instance.
378 * Helper function to resume devfreq device load monitoing. Function
379 * to be called from governor in response to DEVFREQ_GOV_RESUME
380 * event or when polling interval is set to non-zero.
382 void devfreq_monitor_resume(struct devfreq
*devfreq
)
386 mutex_lock(&devfreq
->lock
);
387 if (!devfreq
->stop_polling
)
390 if (!delayed_work_pending(&devfreq
->work
) &&
391 devfreq
->profile
->polling_ms
)
392 queue_delayed_work(devfreq_wq
, &devfreq
->work
,
393 msecs_to_jiffies(devfreq
->profile
->polling_ms
));
395 devfreq
->last_stat_updated
= jiffies
;
396 devfreq
->stop_polling
= false;
398 if (devfreq
->profile
->get_cur_freq
&&
399 !devfreq
->profile
->get_cur_freq(devfreq
->dev
.parent
, &freq
))
400 devfreq
->previous_freq
= freq
;
403 mutex_unlock(&devfreq
->lock
);
405 EXPORT_SYMBOL(devfreq_monitor_resume
);
408 * devfreq_interval_update() - Update device devfreq monitoring interval
409 * @devfreq: the devfreq instance.
410 * @delay: new polling interval to be set.
412 * Helper function to set new load monitoring polling interval. Function
413 * to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
415 void devfreq_interval_update(struct devfreq
*devfreq
, unsigned int *delay
)
417 unsigned int cur_delay
= devfreq
->profile
->polling_ms
;
418 unsigned int new_delay
= *delay
;
420 mutex_lock(&devfreq
->lock
);
421 devfreq
->profile
->polling_ms
= new_delay
;
423 if (devfreq
->stop_polling
)
426 /* if new delay is zero, stop polling */
428 mutex_unlock(&devfreq
->lock
);
429 cancel_delayed_work_sync(&devfreq
->work
);
433 /* if current delay is zero, start polling with new delay */
435 queue_delayed_work(devfreq_wq
, &devfreq
->work
,
436 msecs_to_jiffies(devfreq
->profile
->polling_ms
));
440 /* if current delay is greater than new delay, restart polling */
441 if (cur_delay
> new_delay
) {
442 mutex_unlock(&devfreq
->lock
);
443 cancel_delayed_work_sync(&devfreq
->work
);
444 mutex_lock(&devfreq
->lock
);
445 if (!devfreq
->stop_polling
)
446 queue_delayed_work(devfreq_wq
, &devfreq
->work
,
447 msecs_to_jiffies(devfreq
->profile
->polling_ms
));
450 mutex_unlock(&devfreq
->lock
);
452 EXPORT_SYMBOL(devfreq_interval_update
);
455 * devfreq_notifier_call() - Notify that the device frequency requirements
456 * has been changed out of devfreq framework.
457 * @nb: the notifier_block (supposed to be devfreq->nb)
461 * Called by a notifier that uses devfreq->nb.
463 static int devfreq_notifier_call(struct notifier_block
*nb
, unsigned long type
,
466 struct devfreq
*devfreq
= container_of(nb
, struct devfreq
, nb
);
469 mutex_lock(&devfreq
->lock
);
470 ret
= update_devfreq(devfreq
);
471 mutex_unlock(&devfreq
->lock
);
477 * _remove_devfreq() - Remove devfreq from the list and release its resources.
478 * @devfreq: the devfreq struct
480 static void _remove_devfreq(struct devfreq
*devfreq
)
482 mutex_lock(&devfreq_list_lock
);
483 if (IS_ERR(find_device_devfreq(devfreq
->dev
.parent
))) {
484 mutex_unlock(&devfreq_list_lock
);
485 dev_warn(&devfreq
->dev
, "releasing devfreq which doesn't exist\n");
488 list_del(&devfreq
->node
);
489 mutex_unlock(&devfreq_list_lock
);
491 if (devfreq
->governor
)
492 devfreq
->governor
->event_handler(devfreq
,
493 DEVFREQ_GOV_STOP
, NULL
);
495 if (devfreq
->profile
->exit
)
496 devfreq
->profile
->exit(devfreq
->dev
.parent
);
498 mutex_destroy(&devfreq
->lock
);
503 * devfreq_dev_release() - Callback for struct device to release the device.
504 * @dev: the devfreq device
506 * This calls _remove_devfreq() if _remove_devfreq() is not called.
508 static void devfreq_dev_release(struct device
*dev
)
510 struct devfreq
*devfreq
= to_devfreq(dev
);
512 _remove_devfreq(devfreq
);
516 * devfreq_add_device() - Add devfreq feature to the device
517 * @dev: the device to add devfreq feature.
518 * @profile: device-specific profile to run devfreq.
519 * @governor_name: name of the policy to choose frequency.
520 * @data: private data for the governor. The devfreq framework does not
523 struct devfreq
*devfreq_add_device(struct device
*dev
,
524 struct devfreq_dev_profile
*profile
,
525 const char *governor_name
,
528 struct devfreq
*devfreq
;
529 struct devfreq_governor
*governor
;
532 if (!dev
|| !profile
|| !governor_name
) {
533 dev_err(dev
, "%s: Invalid parameters.\n", __func__
);
534 return ERR_PTR(-EINVAL
);
537 mutex_lock(&devfreq_list_lock
);
538 devfreq
= find_device_devfreq(dev
);
539 mutex_unlock(&devfreq_list_lock
);
540 if (!IS_ERR(devfreq
)) {
541 dev_err(dev
, "%s: Unable to create devfreq for the device. It already has one.\n", __func__
);
546 devfreq
= kzalloc(sizeof(struct devfreq
), GFP_KERNEL
);
548 dev_err(dev
, "%s: Unable to create devfreq for the device\n",
554 mutex_init(&devfreq
->lock
);
555 mutex_lock(&devfreq
->lock
);
556 devfreq
->dev
.parent
= dev
;
557 devfreq
->dev
.class = devfreq_class
;
558 devfreq
->dev
.release
= devfreq_dev_release
;
559 devfreq
->profile
= profile
;
560 strncpy(devfreq
->governor_name
, governor_name
, DEVFREQ_NAME_LEN
);
561 devfreq
->previous_freq
= profile
->initial_freq
;
562 devfreq
->last_status
.current_frequency
= profile
->initial_freq
;
563 devfreq
->data
= data
;
564 devfreq
->nb
.notifier_call
= devfreq_notifier_call
;
566 if (!devfreq
->profile
->max_state
&& !devfreq
->profile
->freq_table
) {
567 mutex_unlock(&devfreq
->lock
);
568 devfreq_set_freq_table(devfreq
);
569 mutex_lock(&devfreq
->lock
);
572 dev_set_name(&devfreq
->dev
, "%s", dev_name(dev
));
573 err
= device_register(&devfreq
->dev
);
575 mutex_unlock(&devfreq
->lock
);
579 devfreq
->trans_table
= devm_kzalloc(&devfreq
->dev
, sizeof(unsigned int) *
580 devfreq
->profile
->max_state
*
581 devfreq
->profile
->max_state
,
583 devfreq
->time_in_state
= devm_kzalloc(&devfreq
->dev
, sizeof(unsigned long) *
584 devfreq
->profile
->max_state
,
586 devfreq
->last_stat_updated
= jiffies
;
588 srcu_init_notifier_head(&devfreq
->transition_notifier_list
);
590 mutex_unlock(&devfreq
->lock
);
592 mutex_lock(&devfreq_list_lock
);
593 list_add(&devfreq
->node
, &devfreq_list
);
595 governor
= find_devfreq_governor(devfreq
->governor_name
);
596 if (IS_ERR(governor
)) {
597 dev_err(dev
, "%s: Unable to find governor for the device\n",
599 err
= PTR_ERR(governor
);
603 devfreq
->governor
= governor
;
604 err
= devfreq
->governor
->event_handler(devfreq
, DEVFREQ_GOV_START
,
607 dev_err(dev
, "%s: Unable to start governor for the device\n",
611 mutex_unlock(&devfreq_list_lock
);
616 list_del(&devfreq
->node
);
617 mutex_unlock(&devfreq_list_lock
);
619 device_unregister(&devfreq
->dev
);
623 EXPORT_SYMBOL(devfreq_add_device
);
626 * devfreq_remove_device() - Remove devfreq feature from a device.
627 * @devfreq: the devfreq instance to be removed
629 * The opposite of devfreq_add_device().
631 int devfreq_remove_device(struct devfreq
*devfreq
)
636 device_unregister(&devfreq
->dev
);
640 EXPORT_SYMBOL(devfreq_remove_device
);
642 static int devm_devfreq_dev_match(struct device
*dev
, void *res
, void *data
)
644 struct devfreq
**r
= res
;
646 if (WARN_ON(!r
|| !*r
))
652 static void devm_devfreq_dev_release(struct device
*dev
, void *res
)
654 devfreq_remove_device(*(struct devfreq
**)res
);
658 * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
659 * @dev: the device to add devfreq feature.
660 * @profile: device-specific profile to run devfreq.
661 * @governor_name: name of the policy to choose frequency.
662 * @data: private data for the governor. The devfreq framework does not
665 * This function manages automatically the memory of devfreq device using device
666 * resource management and simplify the free operation for memory of devfreq
669 struct devfreq
*devm_devfreq_add_device(struct device
*dev
,
670 struct devfreq_dev_profile
*profile
,
671 const char *governor_name
,
674 struct devfreq
**ptr
, *devfreq
;
676 ptr
= devres_alloc(devm_devfreq_dev_release
, sizeof(*ptr
), GFP_KERNEL
);
678 return ERR_PTR(-ENOMEM
);
680 devfreq
= devfreq_add_device(dev
, profile
, governor_name
, data
);
681 if (IS_ERR(devfreq
)) {
683 return ERR_PTR(-ENOMEM
);
687 devres_add(dev
, ptr
);
691 EXPORT_SYMBOL(devm_devfreq_add_device
);
695 * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
696 * @dev - instance to the given device
697 * @index - index into list of devfreq
699 * return the instance of devfreq device
701 struct devfreq
*devfreq_get_devfreq_by_phandle(struct device
*dev
, int index
)
703 struct device_node
*node
;
704 struct devfreq
*devfreq
;
707 return ERR_PTR(-EINVAL
);
710 return ERR_PTR(-EINVAL
);
712 node
= of_parse_phandle(dev
->of_node
, "devfreq", index
);
714 return ERR_PTR(-ENODEV
);
716 mutex_lock(&devfreq_list_lock
);
717 list_for_each_entry(devfreq
, &devfreq_list
, node
) {
718 if (devfreq
->dev
.parent
719 && devfreq
->dev
.parent
->of_node
== node
) {
720 mutex_unlock(&devfreq_list_lock
);
725 mutex_unlock(&devfreq_list_lock
);
728 return ERR_PTR(-EPROBE_DEFER
);
731 struct devfreq
*devfreq_get_devfreq_by_phandle(struct device
*dev
, int index
)
733 return ERR_PTR(-ENODEV
);
735 #endif /* CONFIG_OF */
736 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle
);
739 * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
740 * @dev: the device to add devfreq feature.
741 * @devfreq: the devfreq instance to be removed
743 void devm_devfreq_remove_device(struct device
*dev
, struct devfreq
*devfreq
)
745 WARN_ON(devres_release(dev
, devm_devfreq_dev_release
,
746 devm_devfreq_dev_match
, devfreq
));
748 EXPORT_SYMBOL(devm_devfreq_remove_device
);
751 * devfreq_suspend_device() - Suspend devfreq of a device.
752 * @devfreq: the devfreq instance to be suspended
754 * This function is intended to be called by the pm callbacks
755 * (e.g., runtime_suspend, suspend) of the device driver that
758 int devfreq_suspend_device(struct devfreq
*devfreq
)
763 if (!devfreq
->governor
)
766 return devfreq
->governor
->event_handler(devfreq
,
767 DEVFREQ_GOV_SUSPEND
, NULL
);
769 EXPORT_SYMBOL(devfreq_suspend_device
);
772 * devfreq_resume_device() - Resume devfreq of a device.
773 * @devfreq: the devfreq instance to be resumed
775 * This function is intended to be called by the pm callbacks
776 * (e.g., runtime_resume, resume) of the device driver that
779 int devfreq_resume_device(struct devfreq
*devfreq
)
784 if (!devfreq
->governor
)
787 return devfreq
->governor
->event_handler(devfreq
,
788 DEVFREQ_GOV_RESUME
, NULL
);
790 EXPORT_SYMBOL(devfreq_resume_device
);
793 * devfreq_add_governor() - Add devfreq governor
794 * @governor: the devfreq governor to be added
796 int devfreq_add_governor(struct devfreq_governor
*governor
)
798 struct devfreq_governor
*g
;
799 struct devfreq
*devfreq
;
803 pr_err("%s: Invalid parameters.\n", __func__
);
807 mutex_lock(&devfreq_list_lock
);
808 g
= find_devfreq_governor(governor
->name
);
810 pr_err("%s: governor %s already registered\n", __func__
,
816 list_add(&governor
->node
, &devfreq_governor_list
);
818 list_for_each_entry(devfreq
, &devfreq_list
, node
) {
820 struct device
*dev
= devfreq
->dev
.parent
;
822 if (!strncmp(devfreq
->governor_name
, governor
->name
,
824 /* The following should never occur */
825 if (devfreq
->governor
) {
827 "%s: Governor %s already present\n",
828 __func__
, devfreq
->governor
->name
);
829 ret
= devfreq
->governor
->event_handler(devfreq
,
830 DEVFREQ_GOV_STOP
, NULL
);
833 "%s: Governor %s stop = %d\n",
835 devfreq
->governor
->name
, ret
);
839 devfreq
->governor
= governor
;
840 ret
= devfreq
->governor
->event_handler(devfreq
,
841 DEVFREQ_GOV_START
, NULL
);
843 dev_warn(dev
, "%s: Governor %s start=%d\n",
844 __func__
, devfreq
->governor
->name
,
851 mutex_unlock(&devfreq_list_lock
);
855 EXPORT_SYMBOL(devfreq_add_governor
);
858 * devfreq_remove_governor() - Remove devfreq feature from a device.
859 * @governor: the devfreq governor to be removed
861 int devfreq_remove_governor(struct devfreq_governor
*governor
)
863 struct devfreq_governor
*g
;
864 struct devfreq
*devfreq
;
868 pr_err("%s: Invalid parameters.\n", __func__
);
872 mutex_lock(&devfreq_list_lock
);
873 g
= find_devfreq_governor(governor
->name
);
875 pr_err("%s: governor %s not registered\n", __func__
,
880 list_for_each_entry(devfreq
, &devfreq_list
, node
) {
882 struct device
*dev
= devfreq
->dev
.parent
;
884 if (!strncmp(devfreq
->governor_name
, governor
->name
,
886 /* we should have a devfreq governor! */
887 if (!devfreq
->governor
) {
888 dev_warn(dev
, "%s: Governor %s NOT present\n",
889 __func__
, governor
->name
);
893 ret
= devfreq
->governor
->event_handler(devfreq
,
894 DEVFREQ_GOV_STOP
, NULL
);
896 dev_warn(dev
, "%s: Governor %s stop=%d\n",
897 __func__
, devfreq
->governor
->name
,
900 devfreq
->governor
= NULL
;
904 list_del(&governor
->node
);
906 mutex_unlock(&devfreq_list_lock
);
910 EXPORT_SYMBOL(devfreq_remove_governor
);
912 static ssize_t
governor_show(struct device
*dev
,
913 struct device_attribute
*attr
, char *buf
)
915 if (!to_devfreq(dev
)->governor
)
918 return sprintf(buf
, "%s\n", to_devfreq(dev
)->governor
->name
);
921 static ssize_t
governor_store(struct device
*dev
, struct device_attribute
*attr
,
922 const char *buf
, size_t count
)
924 struct devfreq
*df
= to_devfreq(dev
);
926 char str_governor
[DEVFREQ_NAME_LEN
+ 1];
927 struct devfreq_governor
*governor
;
929 ret
= sscanf(buf
, "%" __stringify(DEVFREQ_NAME_LEN
) "s", str_governor
);
933 mutex_lock(&devfreq_list_lock
);
934 governor
= find_devfreq_governor(str_governor
);
935 if (IS_ERR(governor
)) {
936 ret
= PTR_ERR(governor
);
939 if (df
->governor
== governor
) {
945 ret
= df
->governor
->event_handler(df
, DEVFREQ_GOV_STOP
, NULL
);
947 dev_warn(dev
, "%s: Governor %s not stopped(%d)\n",
948 __func__
, df
->governor
->name
, ret
);
952 df
->governor
= governor
;
953 strncpy(df
->governor_name
, governor
->name
, DEVFREQ_NAME_LEN
);
954 ret
= df
->governor
->event_handler(df
, DEVFREQ_GOV_START
, NULL
);
956 dev_warn(dev
, "%s: Governor %s not started(%d)\n",
957 __func__
, df
->governor
->name
, ret
);
959 mutex_unlock(&devfreq_list_lock
);
965 static DEVICE_ATTR_RW(governor
);
967 static ssize_t
available_governors_show(struct device
*d
,
968 struct device_attribute
*attr
,
971 struct devfreq_governor
*tmp_governor
;
974 mutex_lock(&devfreq_list_lock
);
975 list_for_each_entry(tmp_governor
, &devfreq_governor_list
, node
)
976 count
+= scnprintf(&buf
[count
], (PAGE_SIZE
- count
- 2),
977 "%s ", tmp_governor
->name
);
978 mutex_unlock(&devfreq_list_lock
);
980 /* Truncate the trailing space */
984 count
+= sprintf(&buf
[count
], "\n");
988 static DEVICE_ATTR_RO(available_governors
);
990 static ssize_t
cur_freq_show(struct device
*dev
, struct device_attribute
*attr
,
994 struct devfreq
*devfreq
= to_devfreq(dev
);
996 if (devfreq
->profile
->get_cur_freq
&&
997 !devfreq
->profile
->get_cur_freq(devfreq
->dev
.parent
, &freq
))
998 return sprintf(buf
, "%lu\n", freq
);
1000 return sprintf(buf
, "%lu\n", devfreq
->previous_freq
);
1002 static DEVICE_ATTR_RO(cur_freq
);
1004 static ssize_t
target_freq_show(struct device
*dev
,
1005 struct device_attribute
*attr
, char *buf
)
1007 return sprintf(buf
, "%lu\n", to_devfreq(dev
)->previous_freq
);
1009 static DEVICE_ATTR_RO(target_freq
);
1011 static ssize_t
polling_interval_show(struct device
*dev
,
1012 struct device_attribute
*attr
, char *buf
)
1014 return sprintf(buf
, "%d\n", to_devfreq(dev
)->profile
->polling_ms
);
1017 static ssize_t
polling_interval_store(struct device
*dev
,
1018 struct device_attribute
*attr
,
1019 const char *buf
, size_t count
)
1021 struct devfreq
*df
= to_devfreq(dev
);
1028 ret
= sscanf(buf
, "%u", &value
);
1032 df
->governor
->event_handler(df
, DEVFREQ_GOV_INTERVAL
, &value
);
1037 static DEVICE_ATTR_RW(polling_interval
);
1039 static ssize_t
min_freq_store(struct device
*dev
, struct device_attribute
*attr
,
1040 const char *buf
, size_t count
)
1042 struct devfreq
*df
= to_devfreq(dev
);
1043 unsigned long value
;
1047 ret
= sscanf(buf
, "%lu", &value
);
1051 mutex_lock(&df
->lock
);
1053 if (value
&& max
&& value
> max
) {
1058 df
->min_freq
= value
;
1062 mutex_unlock(&df
->lock
);
1066 static ssize_t
max_freq_store(struct device
*dev
, struct device_attribute
*attr
,
1067 const char *buf
, size_t count
)
1069 struct devfreq
*df
= to_devfreq(dev
);
1070 unsigned long value
;
1074 ret
= sscanf(buf
, "%lu", &value
);
1078 mutex_lock(&df
->lock
);
1080 if (value
&& min
&& value
< min
) {
1085 df
->max_freq
= value
;
1089 mutex_unlock(&df
->lock
);
1093 #define show_one(name) \
1094 static ssize_t name##_show \
1095 (struct device *dev, struct device_attribute *attr, char *buf) \
1097 return sprintf(buf, "%lu\n", to_devfreq(dev)->name); \
1102 static DEVICE_ATTR_RW(min_freq
);
1103 static DEVICE_ATTR_RW(max_freq
);
1105 static ssize_t
available_frequencies_show(struct device
*d
,
1106 struct device_attribute
*attr
,
1109 struct devfreq
*df
= to_devfreq(d
);
1110 struct device
*dev
= df
->dev
.parent
;
1111 struct dev_pm_opp
*opp
;
1113 unsigned long freq
= 0;
1117 opp
= dev_pm_opp_find_freq_ceil(dev
, &freq
);
1121 count
+= scnprintf(&buf
[count
], (PAGE_SIZE
- count
- 2),
1127 /* Truncate the trailing space */
1131 count
+= sprintf(&buf
[count
], "\n");
1135 static DEVICE_ATTR_RO(available_frequencies
);
1137 static ssize_t
trans_stat_show(struct device
*dev
,
1138 struct device_attribute
*attr
, char *buf
)
1140 struct devfreq
*devfreq
= to_devfreq(dev
);
1143 unsigned int max_state
= devfreq
->profile
->max_state
;
1145 if (!devfreq
->stop_polling
&&
1146 devfreq_update_status(devfreq
, devfreq
->previous_freq
))
1149 return sprintf(buf
, "Not Supported.\n");
1151 len
= sprintf(buf
, " From : To\n");
1152 len
+= sprintf(buf
+ len
, " :");
1153 for (i
= 0; i
< max_state
; i
++)
1154 len
+= sprintf(buf
+ len
, "%10lu",
1155 devfreq
->profile
->freq_table
[i
]);
1157 len
+= sprintf(buf
+ len
, " time(ms)\n");
1159 for (i
= 0; i
< max_state
; i
++) {
1160 if (devfreq
->profile
->freq_table
[i
]
1161 == devfreq
->previous_freq
) {
1162 len
+= sprintf(buf
+ len
, "*");
1164 len
+= sprintf(buf
+ len
, " ");
1166 len
+= sprintf(buf
+ len
, "%10lu:",
1167 devfreq
->profile
->freq_table
[i
]);
1168 for (j
= 0; j
< max_state
; j
++)
1169 len
+= sprintf(buf
+ len
, "%10u",
1170 devfreq
->trans_table
[(i
* max_state
) + j
]);
1171 len
+= sprintf(buf
+ len
, "%10u\n",
1172 jiffies_to_msecs(devfreq
->time_in_state
[i
]));
1175 len
+= sprintf(buf
+ len
, "Total transition : %u\n",
1176 devfreq
->total_trans
);
1179 static DEVICE_ATTR_RO(trans_stat
);
1181 static struct attribute
*devfreq_attrs
[] = {
1182 &dev_attr_governor
.attr
,
1183 &dev_attr_available_governors
.attr
,
1184 &dev_attr_cur_freq
.attr
,
1185 &dev_attr_available_frequencies
.attr
,
1186 &dev_attr_target_freq
.attr
,
1187 &dev_attr_polling_interval
.attr
,
1188 &dev_attr_min_freq
.attr
,
1189 &dev_attr_max_freq
.attr
,
1190 &dev_attr_trans_stat
.attr
,
1193 ATTRIBUTE_GROUPS(devfreq
);
1195 static int __init
devfreq_init(void)
1197 devfreq_class
= class_create(THIS_MODULE
, "devfreq");
1198 if (IS_ERR(devfreq_class
)) {
1199 pr_err("%s: couldn't create class\n", __FILE__
);
1200 return PTR_ERR(devfreq_class
);
1203 devfreq_wq
= create_freezable_workqueue("devfreq_wq");
1205 class_destroy(devfreq_class
);
1206 pr_err("%s: couldn't create workqueue\n", __FILE__
);
1209 devfreq_class
->dev_groups
= devfreq_groups
;
1213 subsys_initcall(devfreq_init
);
1216 * The followings are helper functions for devfreq user device drivers with
1221 * devfreq_recommended_opp() - Helper function to get proper OPP for the
1222 * freq value given to target callback.
1223 * @dev: The devfreq user device. (parent of devfreq)
1224 * @freq: The frequency given to target function
1225 * @flags: Flags handed from devfreq framework.
1227 * Locking: This function must be called under rcu_read_lock(). opp is a rcu
1228 * protected pointer. The reason for the same is that the opp pointer which is
1229 * returned will remain valid for use with opp_get_{voltage, freq} only while
1230 * under the locked area. The pointer returned must be used prior to unlocking
1231 * with rcu_read_unlock() to maintain the integrity of the pointer.
1233 struct dev_pm_opp
*devfreq_recommended_opp(struct device
*dev
,
1234 unsigned long *freq
,
1237 struct dev_pm_opp
*opp
;
1239 if (flags
& DEVFREQ_FLAG_LEAST_UPPER_BOUND
) {
1240 /* The freq is an upper bound. opp should be lower */
1241 opp
= dev_pm_opp_find_freq_floor(dev
, freq
);
1243 /* If not available, use the closest opp */
1244 if (opp
== ERR_PTR(-ERANGE
))
1245 opp
= dev_pm_opp_find_freq_ceil(dev
, freq
);
1247 /* The freq is an lower bound. opp should be higher */
1248 opp
= dev_pm_opp_find_freq_ceil(dev
, freq
);
1250 /* If not available, use the closest opp */
1251 if (opp
== ERR_PTR(-ERANGE
))
1252 opp
= dev_pm_opp_find_freq_floor(dev
, freq
);
1257 EXPORT_SYMBOL(devfreq_recommended_opp
);
1260 * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1261 * for any changes in the OPP availability
1263 * @dev: The devfreq user device. (parent of devfreq)
1264 * @devfreq: The devfreq object.
1266 int devfreq_register_opp_notifier(struct device
*dev
, struct devfreq
*devfreq
)
1268 struct srcu_notifier_head
*nh
;
1272 nh
= dev_pm_opp_get_notifier(dev
);
1277 ret
= srcu_notifier_chain_register(nh
, &devfreq
->nb
);
1281 EXPORT_SYMBOL(devfreq_register_opp_notifier
);
1284 * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1285 * notified for any changes in the OPP
1286 * availability changes anymore.
1287 * @dev: The devfreq user device. (parent of devfreq)
1288 * @devfreq: The devfreq object.
1290 * At exit() callback of devfreq_dev_profile, this must be included if
1291 * devfreq_recommended_opp is used.
1293 int devfreq_unregister_opp_notifier(struct device
*dev
, struct devfreq
*devfreq
)
1295 struct srcu_notifier_head
*nh
;
1299 nh
= dev_pm_opp_get_notifier(dev
);
1304 ret
= srcu_notifier_chain_unregister(nh
, &devfreq
->nb
);
1308 EXPORT_SYMBOL(devfreq_unregister_opp_notifier
);
1310 static void devm_devfreq_opp_release(struct device
*dev
, void *res
)
1312 devfreq_unregister_opp_notifier(dev
, *(struct devfreq
**)res
);
1316 * devm_ devfreq_register_opp_notifier()
1317 * - Resource-managed devfreq_register_opp_notifier()
1318 * @dev: The devfreq user device. (parent of devfreq)
1319 * @devfreq: The devfreq object.
1321 int devm_devfreq_register_opp_notifier(struct device
*dev
,
1322 struct devfreq
*devfreq
)
1324 struct devfreq
**ptr
;
1327 ptr
= devres_alloc(devm_devfreq_opp_release
, sizeof(*ptr
), GFP_KERNEL
);
1331 ret
= devfreq_register_opp_notifier(dev
, devfreq
);
1338 devres_add(dev
, ptr
);
1342 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier
);
1345 * devm_devfreq_unregister_opp_notifier()
1346 * - Resource-managed devfreq_unregister_opp_notifier()
1347 * @dev: The devfreq user device. (parent of devfreq)
1348 * @devfreq: The devfreq object.
1350 void devm_devfreq_unregister_opp_notifier(struct device
*dev
,
1351 struct devfreq
*devfreq
)
1353 WARN_ON(devres_release(dev
, devm_devfreq_opp_release
,
1354 devm_devfreq_dev_match
, devfreq
));
1356 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier
);
1359 * devfreq_register_notifier() - Register a driver with devfreq
1360 * @devfreq: The devfreq object.
1361 * @nb: The notifier block to register.
1362 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1364 int devfreq_register_notifier(struct devfreq
*devfreq
,
1365 struct notifier_block
*nb
,
1374 case DEVFREQ_TRANSITION_NOTIFIER
:
1375 ret
= srcu_notifier_chain_register(
1376 &devfreq
->transition_notifier_list
, nb
);
1384 EXPORT_SYMBOL(devfreq_register_notifier
);
1387 * devfreq_unregister_notifier() - Unregister a driver with devfreq
1388 * @devfreq: The devfreq object.
1389 * @nb: The notifier block to be unregistered.
1390 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1392 int devfreq_unregister_notifier(struct devfreq
*devfreq
,
1393 struct notifier_block
*nb
,
1402 case DEVFREQ_TRANSITION_NOTIFIER
:
1403 ret
= srcu_notifier_chain_unregister(
1404 &devfreq
->transition_notifier_list
, nb
);
1412 EXPORT_SYMBOL(devfreq_unregister_notifier
);
1414 struct devfreq_notifier_devres
{
1415 struct devfreq
*devfreq
;
1416 struct notifier_block
*nb
;
1420 static void devm_devfreq_notifier_release(struct device
*dev
, void *res
)
1422 struct devfreq_notifier_devres
*this = res
;
1424 devfreq_unregister_notifier(this->devfreq
, this->nb
, this->list
);
1428 * devm_devfreq_register_notifier()
1429 - Resource-managed devfreq_register_notifier()
1430 * @dev: The devfreq user device. (parent of devfreq)
1431 * @devfreq: The devfreq object.
1432 * @nb: The notifier block to be unregistered.
1433 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1435 int devm_devfreq_register_notifier(struct device
*dev
,
1436 struct devfreq
*devfreq
,
1437 struct notifier_block
*nb
,
1440 struct devfreq_notifier_devres
*ptr
;
1443 ptr
= devres_alloc(devm_devfreq_notifier_release
, sizeof(*ptr
),
1448 ret
= devfreq_register_notifier(devfreq
, nb
, list
);
1454 ptr
->devfreq
= devfreq
;
1457 devres_add(dev
, ptr
);
1461 EXPORT_SYMBOL(devm_devfreq_register_notifier
);
1464 * devm_devfreq_unregister_notifier()
1465 - Resource-managed devfreq_unregister_notifier()
1466 * @dev: The devfreq user device. (parent of devfreq)
1467 * @devfreq: The devfreq object.
1468 * @nb: The notifier block to be unregistered.
1469 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1471 void devm_devfreq_unregister_notifier(struct device
*dev
,
1472 struct devfreq
*devfreq
,
1473 struct notifier_block
*nb
,
1476 WARN_ON(devres_release(dev
, devm_devfreq_notifier_release
,
1477 devm_devfreq_dev_match
, devfreq
));
1479 EXPORT_SYMBOL(devm_devfreq_unregister_notifier
);