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 /* Load monitoring helper functions for governors use */
195 * update_devfreq() - Reevaluate the device and configure frequency.
196 * @devfreq: the devfreq instance.
198 * Note: Lock devfreq->lock before calling update_devfreq
199 * This function is exported for governors.
201 int update_devfreq(struct devfreq
*devfreq
)
207 if (!mutex_is_locked(&devfreq
->lock
)) {
208 WARN(true, "devfreq->lock must be locked by the caller.\n");
212 if (!devfreq
->governor
)
215 /* Reevaluate the proper frequency */
216 err
= devfreq
->governor
->get_target_freq(devfreq
, &freq
);
221 * Adjust the frequency with user freq and QoS.
223 * List from the highest priority
228 if (devfreq
->min_freq
&& freq
< devfreq
->min_freq
) {
229 freq
= devfreq
->min_freq
;
230 flags
&= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND
; /* Use GLB */
232 if (devfreq
->max_freq
&& freq
> devfreq
->max_freq
) {
233 freq
= devfreq
->max_freq
;
234 flags
|= DEVFREQ_FLAG_LEAST_UPPER_BOUND
; /* Use LUB */
237 err
= devfreq
->profile
->target(devfreq
->dev
.parent
, &freq
, flags
);
241 if (devfreq
->profile
->freq_table
)
242 if (devfreq_update_status(devfreq
, freq
))
243 dev_err(&devfreq
->dev
,
244 "Couldn't update frequency transition information.\n");
246 devfreq
->previous_freq
= freq
;
249 EXPORT_SYMBOL(update_devfreq
);
252 * devfreq_monitor() - Periodically poll devfreq objects.
253 * @work: the work struct used to run devfreq_monitor periodically.
256 static void devfreq_monitor(struct work_struct
*work
)
259 struct devfreq
*devfreq
= container_of(work
,
260 struct devfreq
, work
.work
);
262 mutex_lock(&devfreq
->lock
);
263 err
= update_devfreq(devfreq
);
265 dev_err(&devfreq
->dev
, "dvfs failed with (%d) error\n", err
);
267 queue_delayed_work(devfreq_wq
, &devfreq
->work
,
268 msecs_to_jiffies(devfreq
->profile
->polling_ms
));
269 mutex_unlock(&devfreq
->lock
);
273 * devfreq_monitor_start() - Start load monitoring of devfreq instance
274 * @devfreq: the devfreq instance.
276 * Helper function for starting devfreq device load monitoing. By
277 * default delayed work based monitoring is supported. Function
278 * to be called from governor in response to DEVFREQ_GOV_START
279 * event when device is added to devfreq framework.
281 void devfreq_monitor_start(struct devfreq
*devfreq
)
283 INIT_DEFERRABLE_WORK(&devfreq
->work
, devfreq_monitor
);
284 if (devfreq
->profile
->polling_ms
)
285 queue_delayed_work(devfreq_wq
, &devfreq
->work
,
286 msecs_to_jiffies(devfreq
->profile
->polling_ms
));
288 EXPORT_SYMBOL(devfreq_monitor_start
);
291 * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
292 * @devfreq: the devfreq instance.
294 * Helper function to stop devfreq device load monitoing. Function
295 * to be called from governor in response to DEVFREQ_GOV_STOP
296 * event when device is removed from devfreq framework.
298 void devfreq_monitor_stop(struct devfreq
*devfreq
)
300 cancel_delayed_work_sync(&devfreq
->work
);
302 EXPORT_SYMBOL(devfreq_monitor_stop
);
305 * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
306 * @devfreq: the devfreq instance.
308 * Helper function to suspend devfreq device load monitoing. Function
309 * to be called from governor in response to DEVFREQ_GOV_SUSPEND
310 * event or when polling interval is set to zero.
312 * Note: Though this function is same as devfreq_monitor_stop(),
313 * intentionally kept separate to provide hooks for collecting
314 * transition statistics.
316 void devfreq_monitor_suspend(struct devfreq
*devfreq
)
318 mutex_lock(&devfreq
->lock
);
319 if (devfreq
->stop_polling
) {
320 mutex_unlock(&devfreq
->lock
);
324 devfreq_update_status(devfreq
, devfreq
->previous_freq
);
325 devfreq
->stop_polling
= true;
326 mutex_unlock(&devfreq
->lock
);
327 cancel_delayed_work_sync(&devfreq
->work
);
329 EXPORT_SYMBOL(devfreq_monitor_suspend
);
332 * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
333 * @devfreq: the devfreq instance.
335 * Helper function to resume devfreq device load monitoing. Function
336 * to be called from governor in response to DEVFREQ_GOV_RESUME
337 * event or when polling interval is set to non-zero.
339 void devfreq_monitor_resume(struct devfreq
*devfreq
)
343 mutex_lock(&devfreq
->lock
);
344 if (!devfreq
->stop_polling
)
347 if (!delayed_work_pending(&devfreq
->work
) &&
348 devfreq
->profile
->polling_ms
)
349 queue_delayed_work(devfreq_wq
, &devfreq
->work
,
350 msecs_to_jiffies(devfreq
->profile
->polling_ms
));
352 devfreq
->last_stat_updated
= jiffies
;
353 devfreq
->stop_polling
= false;
355 if (devfreq
->profile
->get_cur_freq
&&
356 !devfreq
->profile
->get_cur_freq(devfreq
->dev
.parent
, &freq
))
357 devfreq
->previous_freq
= freq
;
360 mutex_unlock(&devfreq
->lock
);
362 EXPORT_SYMBOL(devfreq_monitor_resume
);
365 * devfreq_interval_update() - Update device devfreq monitoring interval
366 * @devfreq: the devfreq instance.
367 * @delay: new polling interval to be set.
369 * Helper function to set new load monitoring polling interval. Function
370 * to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
372 void devfreq_interval_update(struct devfreq
*devfreq
, unsigned int *delay
)
374 unsigned int cur_delay
= devfreq
->profile
->polling_ms
;
375 unsigned int new_delay
= *delay
;
377 mutex_lock(&devfreq
->lock
);
378 devfreq
->profile
->polling_ms
= new_delay
;
380 if (devfreq
->stop_polling
)
383 /* if new delay is zero, stop polling */
385 mutex_unlock(&devfreq
->lock
);
386 cancel_delayed_work_sync(&devfreq
->work
);
390 /* if current delay is zero, start polling with new delay */
392 queue_delayed_work(devfreq_wq
, &devfreq
->work
,
393 msecs_to_jiffies(devfreq
->profile
->polling_ms
));
397 /* if current delay is greater than new delay, restart polling */
398 if (cur_delay
> new_delay
) {
399 mutex_unlock(&devfreq
->lock
);
400 cancel_delayed_work_sync(&devfreq
->work
);
401 mutex_lock(&devfreq
->lock
);
402 if (!devfreq
->stop_polling
)
403 queue_delayed_work(devfreq_wq
, &devfreq
->work
,
404 msecs_to_jiffies(devfreq
->profile
->polling_ms
));
407 mutex_unlock(&devfreq
->lock
);
409 EXPORT_SYMBOL(devfreq_interval_update
);
412 * devfreq_notifier_call() - Notify that the device frequency requirements
413 * has been changed out of devfreq framework.
414 * @nb: the notifier_block (supposed to be devfreq->nb)
418 * Called by a notifier that uses devfreq->nb.
420 static int devfreq_notifier_call(struct notifier_block
*nb
, unsigned long type
,
423 struct devfreq
*devfreq
= container_of(nb
, struct devfreq
, nb
);
426 mutex_lock(&devfreq
->lock
);
427 ret
= update_devfreq(devfreq
);
428 mutex_unlock(&devfreq
->lock
);
434 * _remove_devfreq() - Remove devfreq from the list and release its resources.
435 * @devfreq: the devfreq struct
437 static void _remove_devfreq(struct devfreq
*devfreq
)
439 mutex_lock(&devfreq_list_lock
);
440 if (IS_ERR(find_device_devfreq(devfreq
->dev
.parent
))) {
441 mutex_unlock(&devfreq_list_lock
);
442 dev_warn(&devfreq
->dev
, "releasing devfreq which doesn't exist\n");
445 list_del(&devfreq
->node
);
446 mutex_unlock(&devfreq_list_lock
);
448 if (devfreq
->governor
)
449 devfreq
->governor
->event_handler(devfreq
,
450 DEVFREQ_GOV_STOP
, NULL
);
452 if (devfreq
->profile
->exit
)
453 devfreq
->profile
->exit(devfreq
->dev
.parent
);
455 mutex_destroy(&devfreq
->lock
);
460 * devfreq_dev_release() - Callback for struct device to release the device.
461 * @dev: the devfreq device
463 * This calls _remove_devfreq() if _remove_devfreq() is not called.
465 static void devfreq_dev_release(struct device
*dev
)
467 struct devfreq
*devfreq
= to_devfreq(dev
);
469 _remove_devfreq(devfreq
);
473 * devfreq_add_device() - Add devfreq feature to the device
474 * @dev: the device to add devfreq feature.
475 * @profile: device-specific profile to run devfreq.
476 * @governor_name: name of the policy to choose frequency.
477 * @data: private data for the governor. The devfreq framework does not
480 struct devfreq
*devfreq_add_device(struct device
*dev
,
481 struct devfreq_dev_profile
*profile
,
482 const char *governor_name
,
485 struct devfreq
*devfreq
;
486 struct devfreq_governor
*governor
;
489 if (!dev
|| !profile
|| !governor_name
) {
490 dev_err(dev
, "%s: Invalid parameters.\n", __func__
);
491 return ERR_PTR(-EINVAL
);
494 mutex_lock(&devfreq_list_lock
);
495 devfreq
= find_device_devfreq(dev
);
496 mutex_unlock(&devfreq_list_lock
);
497 if (!IS_ERR(devfreq
)) {
498 dev_err(dev
, "%s: Unable to create devfreq for the device. It already has one.\n", __func__
);
503 devfreq
= kzalloc(sizeof(struct devfreq
), GFP_KERNEL
);
505 dev_err(dev
, "%s: Unable to create devfreq for the device\n",
511 mutex_init(&devfreq
->lock
);
512 mutex_lock(&devfreq
->lock
);
513 devfreq
->dev
.parent
= dev
;
514 devfreq
->dev
.class = devfreq_class
;
515 devfreq
->dev
.release
= devfreq_dev_release
;
516 devfreq
->profile
= profile
;
517 strncpy(devfreq
->governor_name
, governor_name
, DEVFREQ_NAME_LEN
);
518 devfreq
->previous_freq
= profile
->initial_freq
;
519 devfreq
->data
= data
;
520 devfreq
->nb
.notifier_call
= devfreq_notifier_call
;
522 if (!devfreq
->profile
->max_state
&& !devfreq
->profile
->freq_table
) {
523 mutex_unlock(&devfreq
->lock
);
524 devfreq_set_freq_table(devfreq
);
525 mutex_lock(&devfreq
->lock
);
528 devfreq
->trans_table
= devm_kzalloc(dev
, sizeof(unsigned int) *
529 devfreq
->profile
->max_state
*
530 devfreq
->profile
->max_state
,
532 devfreq
->time_in_state
= devm_kzalloc(dev
, sizeof(unsigned long) *
533 devfreq
->profile
->max_state
,
535 devfreq
->last_stat_updated
= jiffies
;
537 dev_set_name(&devfreq
->dev
, "%s", dev_name(dev
));
538 err
= device_register(&devfreq
->dev
);
540 put_device(&devfreq
->dev
);
541 mutex_unlock(&devfreq
->lock
);
545 mutex_unlock(&devfreq
->lock
);
547 mutex_lock(&devfreq_list_lock
);
548 list_add(&devfreq
->node
, &devfreq_list
);
550 governor
= find_devfreq_governor(devfreq
->governor_name
);
551 if (!IS_ERR(governor
))
552 devfreq
->governor
= governor
;
553 if (devfreq
->governor
)
554 err
= devfreq
->governor
->event_handler(devfreq
,
555 DEVFREQ_GOV_START
, NULL
);
556 mutex_unlock(&devfreq_list_lock
);
558 dev_err(dev
, "%s: Unable to start governor for the device\n",
566 list_del(&devfreq
->node
);
567 device_unregister(&devfreq
->dev
);
572 EXPORT_SYMBOL(devfreq_add_device
);
575 * devfreq_remove_device() - Remove devfreq feature from a device.
576 * @devfreq: the devfreq instance to be removed
578 * The opposite of devfreq_add_device().
580 int devfreq_remove_device(struct devfreq
*devfreq
)
585 device_unregister(&devfreq
->dev
);
586 put_device(&devfreq
->dev
);
590 EXPORT_SYMBOL(devfreq_remove_device
);
592 static int devm_devfreq_dev_match(struct device
*dev
, void *res
, void *data
)
594 struct devfreq
**r
= res
;
596 if (WARN_ON(!r
|| !*r
))
602 static void devm_devfreq_dev_release(struct device
*dev
, void *res
)
604 devfreq_remove_device(*(struct devfreq
**)res
);
608 * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
609 * @dev: the device to add devfreq feature.
610 * @profile: device-specific profile to run devfreq.
611 * @governor_name: name of the policy to choose frequency.
612 * @data: private data for the governor. The devfreq framework does not
615 * This function manages automatically the memory of devfreq device using device
616 * resource management and simplify the free operation for memory of devfreq
619 struct devfreq
*devm_devfreq_add_device(struct device
*dev
,
620 struct devfreq_dev_profile
*profile
,
621 const char *governor_name
,
624 struct devfreq
**ptr
, *devfreq
;
626 ptr
= devres_alloc(devm_devfreq_dev_release
, sizeof(*ptr
), GFP_KERNEL
);
628 return ERR_PTR(-ENOMEM
);
630 devfreq
= devfreq_add_device(dev
, profile
, governor_name
, data
);
631 if (IS_ERR(devfreq
)) {
633 return ERR_PTR(-ENOMEM
);
637 devres_add(dev
, ptr
);
641 EXPORT_SYMBOL(devm_devfreq_add_device
);
645 * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
646 * @dev - instance to the given device
647 * @index - index into list of devfreq
649 * return the instance of devfreq device
651 struct devfreq
*devfreq_get_devfreq_by_phandle(struct device
*dev
, int index
)
653 struct device_node
*node
;
654 struct devfreq
*devfreq
;
657 return ERR_PTR(-EINVAL
);
660 return ERR_PTR(-EINVAL
);
662 node
= of_parse_phandle(dev
->of_node
, "devfreq", index
);
664 return ERR_PTR(-ENODEV
);
666 mutex_lock(&devfreq_list_lock
);
667 list_for_each_entry(devfreq
, &devfreq_list
, node
) {
668 if (devfreq
->dev
.parent
669 && devfreq
->dev
.parent
->of_node
== node
) {
670 mutex_unlock(&devfreq_list_lock
);
674 mutex_unlock(&devfreq_list_lock
);
676 return ERR_PTR(-EPROBE_DEFER
);
679 struct devfreq
*devfreq_get_devfreq_by_phandle(struct device
*dev
, int index
)
681 return ERR_PTR(-ENODEV
);
683 #endif /* CONFIG_OF */
684 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle
);
687 * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
688 * @dev: the device to add devfreq feature.
689 * @devfreq: the devfreq instance to be removed
691 void devm_devfreq_remove_device(struct device
*dev
, struct devfreq
*devfreq
)
693 WARN_ON(devres_release(dev
, devm_devfreq_dev_release
,
694 devm_devfreq_dev_match
, devfreq
));
696 EXPORT_SYMBOL(devm_devfreq_remove_device
);
699 * devfreq_suspend_device() - Suspend devfreq of a device.
700 * @devfreq: the devfreq instance to be suspended
702 * This function is intended to be called by the pm callbacks
703 * (e.g., runtime_suspend, suspend) of the device driver that
706 int devfreq_suspend_device(struct devfreq
*devfreq
)
711 if (!devfreq
->governor
)
714 return devfreq
->governor
->event_handler(devfreq
,
715 DEVFREQ_GOV_SUSPEND
, NULL
);
717 EXPORT_SYMBOL(devfreq_suspend_device
);
720 * devfreq_resume_device() - Resume devfreq of a device.
721 * @devfreq: the devfreq instance to be resumed
723 * This function is intended to be called by the pm callbacks
724 * (e.g., runtime_resume, resume) of the device driver that
727 int devfreq_resume_device(struct devfreq
*devfreq
)
732 if (!devfreq
->governor
)
735 return devfreq
->governor
->event_handler(devfreq
,
736 DEVFREQ_GOV_RESUME
, NULL
);
738 EXPORT_SYMBOL(devfreq_resume_device
);
741 * devfreq_add_governor() - Add devfreq governor
742 * @governor: the devfreq governor to be added
744 int devfreq_add_governor(struct devfreq_governor
*governor
)
746 struct devfreq_governor
*g
;
747 struct devfreq
*devfreq
;
751 pr_err("%s: Invalid parameters.\n", __func__
);
755 mutex_lock(&devfreq_list_lock
);
756 g
= find_devfreq_governor(governor
->name
);
758 pr_err("%s: governor %s already registered\n", __func__
,
764 list_add(&governor
->node
, &devfreq_governor_list
);
766 list_for_each_entry(devfreq
, &devfreq_list
, node
) {
768 struct device
*dev
= devfreq
->dev
.parent
;
770 if (!strncmp(devfreq
->governor_name
, governor
->name
,
772 /* The following should never occur */
773 if (devfreq
->governor
) {
775 "%s: Governor %s already present\n",
776 __func__
, devfreq
->governor
->name
);
777 ret
= devfreq
->governor
->event_handler(devfreq
,
778 DEVFREQ_GOV_STOP
, NULL
);
781 "%s: Governor %s stop = %d\n",
783 devfreq
->governor
->name
, ret
);
787 devfreq
->governor
= governor
;
788 ret
= devfreq
->governor
->event_handler(devfreq
,
789 DEVFREQ_GOV_START
, NULL
);
791 dev_warn(dev
, "%s: Governor %s start=%d\n",
792 __func__
, devfreq
->governor
->name
,
799 mutex_unlock(&devfreq_list_lock
);
803 EXPORT_SYMBOL(devfreq_add_governor
);
806 * devfreq_remove_device() - Remove devfreq feature from a device.
807 * @governor: the devfreq governor to be removed
809 int devfreq_remove_governor(struct devfreq_governor
*governor
)
811 struct devfreq_governor
*g
;
812 struct devfreq
*devfreq
;
816 pr_err("%s: Invalid parameters.\n", __func__
);
820 mutex_lock(&devfreq_list_lock
);
821 g
= find_devfreq_governor(governor
->name
);
823 pr_err("%s: governor %s not registered\n", __func__
,
828 list_for_each_entry(devfreq
, &devfreq_list
, node
) {
830 struct device
*dev
= devfreq
->dev
.parent
;
832 if (!strncmp(devfreq
->governor_name
, governor
->name
,
834 /* we should have a devfreq governor! */
835 if (!devfreq
->governor
) {
836 dev_warn(dev
, "%s: Governor %s NOT present\n",
837 __func__
, governor
->name
);
841 ret
= devfreq
->governor
->event_handler(devfreq
,
842 DEVFREQ_GOV_STOP
, NULL
);
844 dev_warn(dev
, "%s: Governor %s stop=%d\n",
845 __func__
, devfreq
->governor
->name
,
848 devfreq
->governor
= NULL
;
852 list_del(&governor
->node
);
854 mutex_unlock(&devfreq_list_lock
);
858 EXPORT_SYMBOL(devfreq_remove_governor
);
860 static ssize_t
governor_show(struct device
*dev
,
861 struct device_attribute
*attr
, char *buf
)
863 if (!to_devfreq(dev
)->governor
)
866 return sprintf(buf
, "%s\n", to_devfreq(dev
)->governor
->name
);
869 static ssize_t
governor_store(struct device
*dev
, struct device_attribute
*attr
,
870 const char *buf
, size_t count
)
872 struct devfreq
*df
= to_devfreq(dev
);
874 char str_governor
[DEVFREQ_NAME_LEN
+ 1];
875 struct devfreq_governor
*governor
;
877 ret
= sscanf(buf
, "%" __stringify(DEVFREQ_NAME_LEN
) "s", str_governor
);
881 mutex_lock(&devfreq_list_lock
);
882 governor
= find_devfreq_governor(str_governor
);
883 if (IS_ERR(governor
)) {
884 ret
= PTR_ERR(governor
);
887 if (df
->governor
== governor
) {
893 ret
= df
->governor
->event_handler(df
, DEVFREQ_GOV_STOP
, NULL
);
895 dev_warn(dev
, "%s: Governor %s not stopped(%d)\n",
896 __func__
, df
->governor
->name
, ret
);
900 df
->governor
= governor
;
901 strncpy(df
->governor_name
, governor
->name
, DEVFREQ_NAME_LEN
);
902 ret
= df
->governor
->event_handler(df
, DEVFREQ_GOV_START
, NULL
);
904 dev_warn(dev
, "%s: Governor %s not started(%d)\n",
905 __func__
, df
->governor
->name
, ret
);
907 mutex_unlock(&devfreq_list_lock
);
913 static DEVICE_ATTR_RW(governor
);
915 static ssize_t
available_governors_show(struct device
*d
,
916 struct device_attribute
*attr
,
919 struct devfreq_governor
*tmp_governor
;
922 mutex_lock(&devfreq_list_lock
);
923 list_for_each_entry(tmp_governor
, &devfreq_governor_list
, node
)
924 count
+= scnprintf(&buf
[count
], (PAGE_SIZE
- count
- 2),
925 "%s ", tmp_governor
->name
);
926 mutex_unlock(&devfreq_list_lock
);
928 /* Truncate the trailing space */
932 count
+= sprintf(&buf
[count
], "\n");
936 static DEVICE_ATTR_RO(available_governors
);
938 static ssize_t
cur_freq_show(struct device
*dev
, struct device_attribute
*attr
,
942 struct devfreq
*devfreq
= to_devfreq(dev
);
944 if (devfreq
->profile
->get_cur_freq
&&
945 !devfreq
->profile
->get_cur_freq(devfreq
->dev
.parent
, &freq
))
946 return sprintf(buf
, "%lu\n", freq
);
948 return sprintf(buf
, "%lu\n", devfreq
->previous_freq
);
950 static DEVICE_ATTR_RO(cur_freq
);
952 static ssize_t
target_freq_show(struct device
*dev
,
953 struct device_attribute
*attr
, char *buf
)
955 return sprintf(buf
, "%lu\n", to_devfreq(dev
)->previous_freq
);
957 static DEVICE_ATTR_RO(target_freq
);
959 static ssize_t
polling_interval_show(struct device
*dev
,
960 struct device_attribute
*attr
, char *buf
)
962 return sprintf(buf
, "%d\n", to_devfreq(dev
)->profile
->polling_ms
);
965 static ssize_t
polling_interval_store(struct device
*dev
,
966 struct device_attribute
*attr
,
967 const char *buf
, size_t count
)
969 struct devfreq
*df
= to_devfreq(dev
);
976 ret
= sscanf(buf
, "%u", &value
);
980 df
->governor
->event_handler(df
, DEVFREQ_GOV_INTERVAL
, &value
);
985 static DEVICE_ATTR_RW(polling_interval
);
987 static ssize_t
min_freq_store(struct device
*dev
, struct device_attribute
*attr
,
988 const char *buf
, size_t count
)
990 struct devfreq
*df
= to_devfreq(dev
);
995 ret
= sscanf(buf
, "%lu", &value
);
999 mutex_lock(&df
->lock
);
1001 if (value
&& max
&& value
> max
) {
1006 df
->min_freq
= value
;
1010 mutex_unlock(&df
->lock
);
1014 static ssize_t
max_freq_store(struct device
*dev
, struct device_attribute
*attr
,
1015 const char *buf
, size_t count
)
1017 struct devfreq
*df
= to_devfreq(dev
);
1018 unsigned long value
;
1022 ret
= sscanf(buf
, "%lu", &value
);
1026 mutex_lock(&df
->lock
);
1028 if (value
&& min
&& value
< min
) {
1033 df
->max_freq
= value
;
1037 mutex_unlock(&df
->lock
);
1041 #define show_one(name) \
1042 static ssize_t name##_show \
1043 (struct device *dev, struct device_attribute *attr, char *buf) \
1045 return sprintf(buf, "%lu\n", to_devfreq(dev)->name); \
1050 static DEVICE_ATTR_RW(min_freq
);
1051 static DEVICE_ATTR_RW(max_freq
);
1053 static ssize_t
available_frequencies_show(struct device
*d
,
1054 struct device_attribute
*attr
,
1057 struct devfreq
*df
= to_devfreq(d
);
1058 struct device
*dev
= df
->dev
.parent
;
1059 struct dev_pm_opp
*opp
;
1061 unsigned long freq
= 0;
1065 opp
= dev_pm_opp_find_freq_ceil(dev
, &freq
);
1069 count
+= scnprintf(&buf
[count
], (PAGE_SIZE
- count
- 2),
1075 /* Truncate the trailing space */
1079 count
+= sprintf(&buf
[count
], "\n");
1083 static DEVICE_ATTR_RO(available_frequencies
);
1085 static ssize_t
trans_stat_show(struct device
*dev
,
1086 struct device_attribute
*attr
, char *buf
)
1088 struct devfreq
*devfreq
= to_devfreq(dev
);
1091 unsigned int max_state
= devfreq
->profile
->max_state
;
1093 if (!devfreq
->stop_polling
&&
1094 devfreq_update_status(devfreq
, devfreq
->previous_freq
))
1097 return sprintf(buf
, "Not Supported.\n");
1099 len
= sprintf(buf
, " From : To\n");
1100 len
+= sprintf(buf
+ len
, " :");
1101 for (i
= 0; i
< max_state
; i
++)
1102 len
+= sprintf(buf
+ len
, "%10lu",
1103 devfreq
->profile
->freq_table
[i
]);
1105 len
+= sprintf(buf
+ len
, " time(ms)\n");
1107 for (i
= 0; i
< max_state
; i
++) {
1108 if (devfreq
->profile
->freq_table
[i
]
1109 == devfreq
->previous_freq
) {
1110 len
+= sprintf(buf
+ len
, "*");
1112 len
+= sprintf(buf
+ len
, " ");
1114 len
+= sprintf(buf
+ len
, "%10lu:",
1115 devfreq
->profile
->freq_table
[i
]);
1116 for (j
= 0; j
< max_state
; j
++)
1117 len
+= sprintf(buf
+ len
, "%10u",
1118 devfreq
->trans_table
[(i
* max_state
) + j
]);
1119 len
+= sprintf(buf
+ len
, "%10u\n",
1120 jiffies_to_msecs(devfreq
->time_in_state
[i
]));
1123 len
+= sprintf(buf
+ len
, "Total transition : %u\n",
1124 devfreq
->total_trans
);
1127 static DEVICE_ATTR_RO(trans_stat
);
1129 static struct attribute
*devfreq_attrs
[] = {
1130 &dev_attr_governor
.attr
,
1131 &dev_attr_available_governors
.attr
,
1132 &dev_attr_cur_freq
.attr
,
1133 &dev_attr_available_frequencies
.attr
,
1134 &dev_attr_target_freq
.attr
,
1135 &dev_attr_polling_interval
.attr
,
1136 &dev_attr_min_freq
.attr
,
1137 &dev_attr_max_freq
.attr
,
1138 &dev_attr_trans_stat
.attr
,
1141 ATTRIBUTE_GROUPS(devfreq
);
1143 static int __init
devfreq_init(void)
1145 devfreq_class
= class_create(THIS_MODULE
, "devfreq");
1146 if (IS_ERR(devfreq_class
)) {
1147 pr_err("%s: couldn't create class\n", __FILE__
);
1148 return PTR_ERR(devfreq_class
);
1151 devfreq_wq
= create_freezable_workqueue("devfreq_wq");
1153 class_destroy(devfreq_class
);
1154 pr_err("%s: couldn't create workqueue\n", __FILE__
);
1157 devfreq_class
->dev_groups
= devfreq_groups
;
1161 subsys_initcall(devfreq_init
);
1163 static void __exit
devfreq_exit(void)
1165 class_destroy(devfreq_class
);
1166 destroy_workqueue(devfreq_wq
);
1168 module_exit(devfreq_exit
);
1171 * The followings are helper functions for devfreq user device drivers with
1176 * devfreq_recommended_opp() - Helper function to get proper OPP for the
1177 * freq value given to target callback.
1178 * @dev: The devfreq user device. (parent of devfreq)
1179 * @freq: The frequency given to target function
1180 * @flags: Flags handed from devfreq framework.
1182 * Locking: This function must be called under rcu_read_lock(). opp is a rcu
1183 * protected pointer. The reason for the same is that the opp pointer which is
1184 * returned will remain valid for use with opp_get_{voltage, freq} only while
1185 * under the locked area. The pointer returned must be used prior to unlocking
1186 * with rcu_read_unlock() to maintain the integrity of the pointer.
1188 struct dev_pm_opp
*devfreq_recommended_opp(struct device
*dev
,
1189 unsigned long *freq
,
1192 struct dev_pm_opp
*opp
;
1194 if (flags
& DEVFREQ_FLAG_LEAST_UPPER_BOUND
) {
1195 /* The freq is an upper bound. opp should be lower */
1196 opp
= dev_pm_opp_find_freq_floor(dev
, freq
);
1198 /* If not available, use the closest opp */
1199 if (opp
== ERR_PTR(-ERANGE
))
1200 opp
= dev_pm_opp_find_freq_ceil(dev
, freq
);
1202 /* The freq is an lower bound. opp should be higher */
1203 opp
= dev_pm_opp_find_freq_ceil(dev
, freq
);
1205 /* If not available, use the closest opp */
1206 if (opp
== ERR_PTR(-ERANGE
))
1207 opp
= dev_pm_opp_find_freq_floor(dev
, freq
);
1212 EXPORT_SYMBOL(devfreq_recommended_opp
);
1215 * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1216 * for any changes in the OPP availability
1218 * @dev: The devfreq user device. (parent of devfreq)
1219 * @devfreq: The devfreq object.
1221 int devfreq_register_opp_notifier(struct device
*dev
, struct devfreq
*devfreq
)
1223 struct srcu_notifier_head
*nh
;
1227 nh
= dev_pm_opp_get_notifier(dev
);
1232 ret
= srcu_notifier_chain_register(nh
, &devfreq
->nb
);
1236 EXPORT_SYMBOL(devfreq_register_opp_notifier
);
1239 * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1240 * notified for any changes in the OPP
1241 * availability changes anymore.
1242 * @dev: The devfreq user device. (parent of devfreq)
1243 * @devfreq: The devfreq object.
1245 * At exit() callback of devfreq_dev_profile, this must be included if
1246 * devfreq_recommended_opp is used.
1248 int devfreq_unregister_opp_notifier(struct device
*dev
, struct devfreq
*devfreq
)
1250 struct srcu_notifier_head
*nh
;
1254 nh
= dev_pm_opp_get_notifier(dev
);
1259 ret
= srcu_notifier_chain_unregister(nh
, &devfreq
->nb
);
1263 EXPORT_SYMBOL(devfreq_unregister_opp_notifier
);
1265 static void devm_devfreq_opp_release(struct device
*dev
, void *res
)
1267 devfreq_unregister_opp_notifier(dev
, *(struct devfreq
**)res
);
1271 * devm_ devfreq_register_opp_notifier()
1272 * - Resource-managed devfreq_register_opp_notifier()
1273 * @dev: The devfreq user device. (parent of devfreq)
1274 * @devfreq: The devfreq object.
1276 int devm_devfreq_register_opp_notifier(struct device
*dev
,
1277 struct devfreq
*devfreq
)
1279 struct devfreq
**ptr
;
1282 ptr
= devres_alloc(devm_devfreq_opp_release
, sizeof(*ptr
), GFP_KERNEL
);
1286 ret
= devfreq_register_opp_notifier(dev
, devfreq
);
1293 devres_add(dev
, ptr
);
1297 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier
);
1300 * devm_devfreq_unregister_opp_notifier()
1301 * - Resource-managed devfreq_unregister_opp_notifier()
1302 * @dev: The devfreq user device. (parent of devfreq)
1303 * @devfreq: The devfreq object.
1305 void devm_devfreq_unregister_opp_notifier(struct device
*dev
,
1306 struct devfreq
*devfreq
)
1308 WARN_ON(devres_release(dev
, devm_devfreq_opp_release
,
1309 devm_devfreq_dev_match
, devfreq
));
1311 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier
);
1313 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
1314 MODULE_DESCRIPTION("devfreq class support");
1315 MODULE_LICENSE("GPL");