2 * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
5 * Copyright (C) 2011 Samsung Electronics
6 * MyungJoo Ham <myungjoo.ham@samsung.com>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
13 #include <linux/kernel.h>
14 #include <linux/sched.h>
15 #include <linux/errno.h>
16 #include <linux/err.h>
17 #include <linux/init.h>
18 #include <linux/export.h>
19 #include <linux/slab.h>
20 #include <linux/stat.h>
21 #include <linux/pm_opp.h>
22 #include <linux/devfreq.h>
23 #include <linux/workqueue.h>
24 #include <linux/platform_device.h>
25 #include <linux/list.h>
26 #include <linux/printk.h>
27 #include <linux/hrtimer.h>
31 static struct class *devfreq_class;
34 * devfreq core provides delayed work based load monitoring helper
35 * functions. Governors can use these or can implement their own
36 * monitoring mechanism.
38 static struct workqueue_struct *devfreq_wq;
40 /* The list of all device-devfreq governors */
41 static LIST_HEAD(devfreq_governor_list);
42 /* The list of all device-devfreq */
43 static LIST_HEAD(devfreq_list);
44 static DEFINE_MUTEX(devfreq_list_lock);
47 * find_device_devfreq() - find devfreq struct using device pointer
48 * @dev: device pointer used to lookup device devfreq.
50 * Search the list of device devfreqs and return the matched device's
51 * devfreq info. devfreq_list_lock should be held by the caller.
53 static struct devfreq *find_device_devfreq(struct device *dev)
55 struct devfreq *tmp_devfreq;
57 if (IS_ERR_OR_NULL(dev)) {
58 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
59 return ERR_PTR(-EINVAL);
61 WARN(!mutex_is_locked(&devfreq_list_lock),
62 "devfreq_list_lock must be locked.");
64 list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
65 if (tmp_devfreq->dev.parent == dev)
69 return ERR_PTR(-ENODEV);
73 * devfreq_get_freq_level() - Lookup freq_table for the frequency
74 * @devfreq: the devfreq instance
75 * @freq: the target frequency
77 static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
81 for (lev = 0; lev < devfreq->profile->max_state; lev++)
82 if (freq == devfreq->profile->freq_table[lev])
89 * devfreq_set_freq_table() - Initialize freq_table for the frequency
90 * @devfreq: the devfreq instance
92 static void devfreq_set_freq_table(struct devfreq *devfreq)
94 struct devfreq_dev_profile *profile = devfreq->profile;
95 struct dev_pm_opp *opp;
99 /* Initialize the freq_table from OPP table */
100 count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
104 profile->max_state = count;
105 profile->freq_table = devm_kcalloc(devfreq->dev.parent,
107 sizeof(*profile->freq_table),
109 if (!profile->freq_table) {
110 profile->max_state = 0;
115 for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
116 opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
118 devm_kfree(devfreq->dev.parent, profile->freq_table);
119 profile->max_state = 0;
123 profile->freq_table[i] = freq;
129 * devfreq_update_status() - Update statistics of devfreq behavior
130 * @devfreq: the devfreq instance
131 * @freq: the update target frequency
133 int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
135 int lev, prev_lev, ret = 0;
136 unsigned long cur_time;
138 lockdep_assert_held(&devfreq->lock);
141 /* Immediately exit if previous_freq is not initialized yet. */
142 if (!devfreq->previous_freq)
145 prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
151 devfreq->time_in_state[prev_lev] +=
152 cur_time - devfreq->last_stat_updated;
154 lev = devfreq_get_freq_level(devfreq, freq);
160 if (lev != prev_lev) {
161 devfreq->trans_table[(prev_lev *
162 devfreq->profile->max_state) + lev]++;
163 devfreq->total_trans++;
167 devfreq->last_stat_updated = cur_time;
170 EXPORT_SYMBOL(devfreq_update_status);
173 * find_devfreq_governor() - find devfreq governor from name
174 * @name: name of the governor
176 * Search the list of devfreq governors and return the matched
177 * governor's pointer. devfreq_list_lock should be held by the caller.
179 static struct devfreq_governor *find_devfreq_governor(const char *name)
181 struct devfreq_governor *tmp_governor;
183 if (IS_ERR_OR_NULL(name)) {
184 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
185 return ERR_PTR(-EINVAL);
187 WARN(!mutex_is_locked(&devfreq_list_lock),
188 "devfreq_list_lock must be locked.");
190 list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
191 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
195 return ERR_PTR(-ENODEV);
198 static int devfreq_notify_transition(struct devfreq *devfreq,
199 struct devfreq_freqs *freqs, unsigned int state)
205 case DEVFREQ_PRECHANGE:
206 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
207 DEVFREQ_PRECHANGE, freqs);
210 case DEVFREQ_POSTCHANGE:
211 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
212 DEVFREQ_POSTCHANGE, freqs);
221 /* Load monitoring helper functions for governors use */
224 * update_devfreq() - Reevaluate the device and configure frequency.
225 * @devfreq: the devfreq instance.
227 * Note: Lock devfreq->lock before calling update_devfreq
228 * This function is exported for governors.
230 int update_devfreq(struct devfreq *devfreq)
232 struct devfreq_freqs freqs;
233 unsigned long freq, cur_freq;
237 if (!mutex_is_locked(&devfreq->lock)) {
238 WARN(true, "devfreq->lock must be locked by the caller.\n");
242 if (!devfreq->governor)
245 /* Reevaluate the proper frequency */
246 err = devfreq->governor->get_target_freq(devfreq, &freq);
251 * Adjust the frequency with user freq and QoS.
253 * List from the highest priority
258 if (devfreq->min_freq && freq < devfreq->min_freq) {
259 freq = devfreq->min_freq;
260 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
262 if (devfreq->max_freq && freq > devfreq->max_freq) {
263 freq = devfreq->max_freq;
264 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
267 if (devfreq->profile->get_cur_freq)
268 devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
270 cur_freq = devfreq->previous_freq;
272 freqs.old = cur_freq;
274 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
276 err = devfreq->profile->target(devfreq->dev.parent, &freq, flags);
278 freqs.new = cur_freq;
279 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
284 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
286 if (devfreq->profile->freq_table)
287 if (devfreq_update_status(devfreq, freq))
288 dev_err(&devfreq->dev,
289 "Couldn't update frequency transition information.\n");
291 devfreq->previous_freq = freq;
294 EXPORT_SYMBOL(update_devfreq);
297 * devfreq_monitor() - Periodically poll devfreq objects.
298 * @work: the work struct used to run devfreq_monitor periodically.
301 static void devfreq_monitor(struct work_struct *work)
304 struct devfreq *devfreq = container_of(work,
305 struct devfreq, work.work);
307 mutex_lock(&devfreq->lock);
308 err = update_devfreq(devfreq);
310 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
312 queue_delayed_work(devfreq_wq, &devfreq->work,
313 msecs_to_jiffies(devfreq->profile->polling_ms));
314 mutex_unlock(&devfreq->lock);
318 * devfreq_monitor_start() - Start load monitoring of devfreq instance
319 * @devfreq: the devfreq instance.
321 * Helper function for starting devfreq device load monitoing. By
322 * default delayed work based monitoring is supported. Function
323 * to be called from governor in response to DEVFREQ_GOV_START
324 * event when device is added to devfreq framework.
326 void devfreq_monitor_start(struct devfreq *devfreq)
328 INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
329 if (devfreq->profile->polling_ms)
330 queue_delayed_work(devfreq_wq, &devfreq->work,
331 msecs_to_jiffies(devfreq->profile->polling_ms));
333 EXPORT_SYMBOL(devfreq_monitor_start);
336 * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
337 * @devfreq: the devfreq instance.
339 * Helper function to stop devfreq device load monitoing. Function
340 * to be called from governor in response to DEVFREQ_GOV_STOP
341 * event when device is removed from devfreq framework.
343 void devfreq_monitor_stop(struct devfreq *devfreq)
345 cancel_delayed_work_sync(&devfreq->work);
347 EXPORT_SYMBOL(devfreq_monitor_stop);
350 * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
351 * @devfreq: the devfreq instance.
353 * Helper function to suspend devfreq device load monitoing. Function
354 * to be called from governor in response to DEVFREQ_GOV_SUSPEND
355 * event or when polling interval is set to zero.
357 * Note: Though this function is same as devfreq_monitor_stop(),
358 * intentionally kept separate to provide hooks for collecting
359 * transition statistics.
361 void devfreq_monitor_suspend(struct devfreq *devfreq)
363 mutex_lock(&devfreq->lock);
364 if (devfreq->stop_polling) {
365 mutex_unlock(&devfreq->lock);
369 devfreq_update_status(devfreq, devfreq->previous_freq);
370 devfreq->stop_polling = true;
371 mutex_unlock(&devfreq->lock);
372 cancel_delayed_work_sync(&devfreq->work);
374 EXPORT_SYMBOL(devfreq_monitor_suspend);
377 * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
378 * @devfreq: the devfreq instance.
380 * Helper function to resume devfreq device load monitoing. Function
381 * to be called from governor in response to DEVFREQ_GOV_RESUME
382 * event or when polling interval is set to non-zero.
384 void devfreq_monitor_resume(struct devfreq *devfreq)
388 mutex_lock(&devfreq->lock);
389 if (!devfreq->stop_polling)
392 if (!delayed_work_pending(&devfreq->work) &&
393 devfreq->profile->polling_ms)
394 queue_delayed_work(devfreq_wq, &devfreq->work,
395 msecs_to_jiffies(devfreq->profile->polling_ms));
397 devfreq->last_stat_updated = jiffies;
398 devfreq->stop_polling = false;
400 if (devfreq->profile->get_cur_freq &&
401 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
402 devfreq->previous_freq = freq;
405 mutex_unlock(&devfreq->lock);
407 EXPORT_SYMBOL(devfreq_monitor_resume);
410 * devfreq_interval_update() - Update device devfreq monitoring interval
411 * @devfreq: the devfreq instance.
412 * @delay: new polling interval to be set.
414 * Helper function to set new load monitoring polling interval. Function
415 * to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
417 void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
419 unsigned int cur_delay = devfreq->profile->polling_ms;
420 unsigned int new_delay = *delay;
422 mutex_lock(&devfreq->lock);
423 devfreq->profile->polling_ms = new_delay;
425 if (devfreq->stop_polling)
428 /* if new delay is zero, stop polling */
430 mutex_unlock(&devfreq->lock);
431 cancel_delayed_work_sync(&devfreq->work);
435 /* if current delay is zero, start polling with new delay */
437 queue_delayed_work(devfreq_wq, &devfreq->work,
438 msecs_to_jiffies(devfreq->profile->polling_ms));
442 /* if current delay is greater than new delay, restart polling */
443 if (cur_delay > new_delay) {
444 mutex_unlock(&devfreq->lock);
445 cancel_delayed_work_sync(&devfreq->work);
446 mutex_lock(&devfreq->lock);
447 if (!devfreq->stop_polling)
448 queue_delayed_work(devfreq_wq, &devfreq->work,
449 msecs_to_jiffies(devfreq->profile->polling_ms));
452 mutex_unlock(&devfreq->lock);
454 EXPORT_SYMBOL(devfreq_interval_update);
457 * devfreq_notifier_call() - Notify that the device frequency requirements
458 * has been changed out of devfreq framework.
459 * @nb: the notifier_block (supposed to be devfreq->nb)
463 * Called by a notifier that uses devfreq->nb.
465 static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
468 struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
471 mutex_lock(&devfreq->lock);
472 ret = update_devfreq(devfreq);
473 mutex_unlock(&devfreq->lock);
479 * _remove_devfreq() - Remove devfreq from the list and release its resources.
480 * @devfreq: the devfreq struct
482 static void _remove_devfreq(struct devfreq *devfreq)
484 mutex_lock(&devfreq_list_lock);
485 list_del(&devfreq->node);
486 mutex_unlock(&devfreq_list_lock);
488 if (devfreq->governor)
489 devfreq->governor->event_handler(devfreq,
490 DEVFREQ_GOV_STOP, NULL);
492 if (devfreq->profile->exit)
493 devfreq->profile->exit(devfreq->dev.parent);
495 mutex_destroy(&devfreq->lock);
500 * devfreq_dev_release() - Callback for struct device to release the device.
501 * @dev: the devfreq device
503 * This calls _remove_devfreq() if _remove_devfreq() is not called.
505 static void devfreq_dev_release(struct device *dev)
507 struct devfreq *devfreq = to_devfreq(dev);
509 _remove_devfreq(devfreq);
513 * devfreq_add_device() - Add devfreq feature to the device
514 * @dev: the device to add devfreq feature.
515 * @profile: device-specific profile to run devfreq.
516 * @governor_name: name of the policy to choose frequency.
517 * @data: private data for the governor. The devfreq framework does not
520 struct devfreq *devfreq_add_device(struct device *dev,
521 struct devfreq_dev_profile *profile,
522 const char *governor_name,
525 struct devfreq *devfreq;
526 struct devfreq_governor *governor;
529 if (!dev || !profile || !governor_name) {
530 dev_err(dev, "%s: Invalid parameters.\n", __func__);
531 return ERR_PTR(-EINVAL);
534 mutex_lock(&devfreq_list_lock);
535 devfreq = find_device_devfreq(dev);
536 mutex_unlock(&devfreq_list_lock);
537 if (!IS_ERR(devfreq)) {
538 dev_err(dev, "%s: Unable to create devfreq for the device. It already has one.\n", __func__);
543 devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
545 dev_err(dev, "%s: Unable to create devfreq for the device\n",
551 mutex_init(&devfreq->lock);
552 mutex_lock(&devfreq->lock);
553 devfreq->dev.parent = dev;
554 devfreq->dev.class = devfreq_class;
555 devfreq->dev.release = devfreq_dev_release;
556 INIT_LIST_HEAD(&devfreq->node);
557 devfreq->profile = profile;
558 strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
559 devfreq->previous_freq = profile->initial_freq;
560 devfreq->last_status.current_frequency = profile->initial_freq;
561 devfreq->data = data;
562 devfreq->nb.notifier_call = devfreq_notifier_call;
564 if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
565 mutex_unlock(&devfreq->lock);
566 devfreq_set_freq_table(devfreq);
567 mutex_lock(&devfreq->lock);
570 dev_set_name(&devfreq->dev, "%s", dev_name(dev));
571 err = device_register(&devfreq->dev);
573 mutex_unlock(&devfreq->lock);
577 devfreq->trans_table = devm_kzalloc(&devfreq->dev, sizeof(unsigned int) *
578 devfreq->profile->max_state *
579 devfreq->profile->max_state,
581 devfreq->time_in_state = devm_kzalloc(&devfreq->dev, sizeof(unsigned long) *
582 devfreq->profile->max_state,
584 devfreq->last_stat_updated = jiffies;
586 srcu_init_notifier_head(&devfreq->transition_notifier_list);
588 mutex_unlock(&devfreq->lock);
590 mutex_lock(&devfreq_list_lock);
591 list_add(&devfreq->node, &devfreq_list);
593 governor = find_devfreq_governor(devfreq->governor_name);
594 if (IS_ERR(governor)) {
595 dev_err(dev, "%s: Unable to find governor for the device\n",
597 err = PTR_ERR(governor);
601 devfreq->governor = governor;
602 err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
605 dev_err(dev, "%s: Unable to start governor for the device\n",
609 mutex_unlock(&devfreq_list_lock);
614 list_del(&devfreq->node);
615 mutex_unlock(&devfreq_list_lock);
617 device_unregister(&devfreq->dev);
624 EXPORT_SYMBOL(devfreq_add_device);
627 * devfreq_remove_device() - Remove devfreq feature from a device.
628 * @devfreq: the devfreq instance to be removed
630 * The opposite of devfreq_add_device().
632 int devfreq_remove_device(struct devfreq *devfreq)
637 device_unregister(&devfreq->dev);
641 EXPORT_SYMBOL(devfreq_remove_device);
643 static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
645 struct devfreq **r = res;
647 if (WARN_ON(!r || !*r))
653 static void devm_devfreq_dev_release(struct device *dev, void *res)
655 devfreq_remove_device(*(struct devfreq **)res);
659 * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
660 * @dev: the device to add devfreq feature.
661 * @profile: device-specific profile to run devfreq.
662 * @governor_name: name of the policy to choose frequency.
663 * @data: private data for the governor. The devfreq framework does not
666 * This function manages automatically the memory of devfreq device using device
667 * resource management and simplify the free operation for memory of devfreq
670 struct devfreq *devm_devfreq_add_device(struct device *dev,
671 struct devfreq_dev_profile *profile,
672 const char *governor_name,
675 struct devfreq **ptr, *devfreq;
677 ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
679 return ERR_PTR(-ENOMEM);
681 devfreq = devfreq_add_device(dev, profile, governor_name, data);
682 if (IS_ERR(devfreq)) {
688 devres_add(dev, ptr);
692 EXPORT_SYMBOL(devm_devfreq_add_device);
696 * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
697 * @dev - instance to the given device
698 * @index - index into list of devfreq
700 * return the instance of devfreq device
702 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
704 struct device_node *node;
705 struct devfreq *devfreq;
708 return ERR_PTR(-EINVAL);
711 return ERR_PTR(-EINVAL);
713 node = of_parse_phandle(dev->of_node, "devfreq", index);
715 return ERR_PTR(-ENODEV);
717 mutex_lock(&devfreq_list_lock);
718 list_for_each_entry(devfreq, &devfreq_list, node) {
719 if (devfreq->dev.parent
720 && devfreq->dev.parent->of_node == node) {
721 mutex_unlock(&devfreq_list_lock);
726 mutex_unlock(&devfreq_list_lock);
729 return ERR_PTR(-EPROBE_DEFER);
732 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
734 return ERR_PTR(-ENODEV);
736 #endif /* CONFIG_OF */
737 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
740 * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
741 * @dev: the device to add devfreq feature.
742 * @devfreq: the devfreq instance to be removed
744 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
746 WARN_ON(devres_release(dev, devm_devfreq_dev_release,
747 devm_devfreq_dev_match, devfreq));
749 EXPORT_SYMBOL(devm_devfreq_remove_device);
752 * devfreq_suspend_device() - Suspend devfreq of a device.
753 * @devfreq: the devfreq instance to be suspended
755 * This function is intended to be called by the pm callbacks
756 * (e.g., runtime_suspend, suspend) of the device driver that
759 int devfreq_suspend_device(struct devfreq *devfreq)
764 if (!devfreq->governor)
767 return devfreq->governor->event_handler(devfreq,
768 DEVFREQ_GOV_SUSPEND, NULL);
770 EXPORT_SYMBOL(devfreq_suspend_device);
773 * devfreq_resume_device() - Resume devfreq of a device.
774 * @devfreq: the devfreq instance to be resumed
776 * This function is intended to be called by the pm callbacks
777 * (e.g., runtime_resume, resume) of the device driver that
780 int devfreq_resume_device(struct devfreq *devfreq)
785 if (!devfreq->governor)
788 return devfreq->governor->event_handler(devfreq,
789 DEVFREQ_GOV_RESUME, NULL);
791 EXPORT_SYMBOL(devfreq_resume_device);
794 * devfreq_add_governor() - Add devfreq governor
795 * @governor: the devfreq governor to be added
797 int devfreq_add_governor(struct devfreq_governor *governor)
799 struct devfreq_governor *g;
800 struct devfreq *devfreq;
804 pr_err("%s: Invalid parameters.\n", __func__);
808 mutex_lock(&devfreq_list_lock);
809 g = find_devfreq_governor(governor->name);
811 pr_err("%s: governor %s already registered\n", __func__,
817 list_add(&governor->node, &devfreq_governor_list);
819 list_for_each_entry(devfreq, &devfreq_list, node) {
821 struct device *dev = devfreq->dev.parent;
823 if (!strncmp(devfreq->governor_name, governor->name,
825 /* The following should never occur */
826 if (devfreq->governor) {
828 "%s: Governor %s already present\n",
829 __func__, devfreq->governor->name);
830 ret = devfreq->governor->event_handler(devfreq,
831 DEVFREQ_GOV_STOP, NULL);
834 "%s: Governor %s stop = %d\n",
836 devfreq->governor->name, ret);
840 devfreq->governor = governor;
841 ret = devfreq->governor->event_handler(devfreq,
842 DEVFREQ_GOV_START, NULL);
844 dev_warn(dev, "%s: Governor %s start=%d\n",
845 __func__, devfreq->governor->name,
852 mutex_unlock(&devfreq_list_lock);
856 EXPORT_SYMBOL(devfreq_add_governor);
859 * devfreq_remove_device() - Remove devfreq feature from a device.
860 * @governor: the devfreq governor to be removed
862 int devfreq_remove_governor(struct devfreq_governor *governor)
864 struct devfreq_governor *g;
865 struct devfreq *devfreq;
869 pr_err("%s: Invalid parameters.\n", __func__);
873 mutex_lock(&devfreq_list_lock);
874 g = find_devfreq_governor(governor->name);
876 pr_err("%s: governor %s not registered\n", __func__,
881 list_for_each_entry(devfreq, &devfreq_list, node) {
883 struct device *dev = devfreq->dev.parent;
885 if (!strncmp(devfreq->governor_name, governor->name,
887 /* we should have a devfreq governor! */
888 if (!devfreq->governor) {
889 dev_warn(dev, "%s: Governor %s NOT present\n",
890 __func__, governor->name);
894 ret = devfreq->governor->event_handler(devfreq,
895 DEVFREQ_GOV_STOP, NULL);
897 dev_warn(dev, "%s: Governor %s stop=%d\n",
898 __func__, devfreq->governor->name,
901 devfreq->governor = NULL;
905 list_del(&governor->node);
907 mutex_unlock(&devfreq_list_lock);
911 EXPORT_SYMBOL(devfreq_remove_governor);
913 static ssize_t governor_show(struct device *dev,
914 struct device_attribute *attr, char *buf)
916 if (!to_devfreq(dev)->governor)
919 return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name);
922 static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
923 const char *buf, size_t count)
925 struct devfreq *df = to_devfreq(dev);
927 char str_governor[DEVFREQ_NAME_LEN + 1];
928 struct devfreq_governor *governor;
930 ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
934 mutex_lock(&devfreq_list_lock);
935 governor = find_devfreq_governor(str_governor);
936 if (IS_ERR(governor)) {
937 ret = PTR_ERR(governor);
940 if (df->governor == governor) {
943 } else if ((df->governor && df->governor->immutable) ||
944 governor->immutable) {
950 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
952 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
953 __func__, df->governor->name, ret);
957 df->governor = governor;
958 strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
959 ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
961 dev_warn(dev, "%s: Governor %s not started(%d)\n",
962 __func__, df->governor->name, ret);
964 mutex_unlock(&devfreq_list_lock);
970 static DEVICE_ATTR_RW(governor);
972 static ssize_t available_governors_show(struct device *d,
973 struct device_attribute *attr,
976 struct devfreq *df = to_devfreq(d);
979 mutex_lock(&devfreq_list_lock);
982 * The devfreq with immutable governor (e.g., passive) shows
985 if (df->governor && df->governor->immutable) {
986 count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
987 "%s ", df->governor_name);
989 * The devfreq device shows the registered governor except for
990 * immutable governors such as passive governor .
993 struct devfreq_governor *governor;
995 list_for_each_entry(governor, &devfreq_governor_list, node) {
996 if (governor->immutable)
998 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
999 "%s ", governor->name);
1003 mutex_unlock(&devfreq_list_lock);
1005 /* Truncate the trailing space */
1009 count += sprintf(&buf[count], "\n");
1013 static DEVICE_ATTR_RO(available_governors);
1015 static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
1019 struct devfreq *devfreq = to_devfreq(dev);
1021 if (devfreq->profile->get_cur_freq &&
1022 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
1023 return sprintf(buf, "%lu\n", freq);
1025 return sprintf(buf, "%lu\n", devfreq->previous_freq);
1027 static DEVICE_ATTR_RO(cur_freq);
1029 static ssize_t target_freq_show(struct device *dev,
1030 struct device_attribute *attr, char *buf)
1032 return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
1034 static DEVICE_ATTR_RO(target_freq);
1036 static ssize_t polling_interval_show(struct device *dev,
1037 struct device_attribute *attr, char *buf)
1039 return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
1042 static ssize_t polling_interval_store(struct device *dev,
1043 struct device_attribute *attr,
1044 const char *buf, size_t count)
1046 struct devfreq *df = to_devfreq(dev);
1053 ret = sscanf(buf, "%u", &value);
1057 df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
1062 static DEVICE_ATTR_RW(polling_interval);
1064 static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1065 const char *buf, size_t count)
1067 struct devfreq *df = to_devfreq(dev);
1068 unsigned long value;
1072 ret = sscanf(buf, "%lu", &value);
1076 mutex_lock(&df->lock);
1078 if (value && max && value > max) {
1083 df->min_freq = value;
1087 mutex_unlock(&df->lock);
1091 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1092 const char *buf, size_t count)
1094 struct devfreq *df = to_devfreq(dev);
1095 unsigned long value;
1099 ret = sscanf(buf, "%lu", &value);
1103 mutex_lock(&df->lock);
1105 if (value && min && value < min) {
1110 df->max_freq = value;
1114 mutex_unlock(&df->lock);
1118 #define show_one(name) \
1119 static ssize_t name##_show \
1120 (struct device *dev, struct device_attribute *attr, char *buf) \
1122 return sprintf(buf, "%lu\n", to_devfreq(dev)->name); \
1127 static DEVICE_ATTR_RW(min_freq);
1128 static DEVICE_ATTR_RW(max_freq);
1130 static ssize_t available_frequencies_show(struct device *d,
1131 struct device_attribute *attr,
1134 struct devfreq *df = to_devfreq(d);
1135 struct device *dev = df->dev.parent;
1136 struct dev_pm_opp *opp;
1138 unsigned long freq = 0;
1142 opp = dev_pm_opp_find_freq_ceil(dev, &freq);
1146 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1152 /* Truncate the trailing space */
1156 count += sprintf(&buf[count], "\n");
1160 static DEVICE_ATTR_RO(available_frequencies);
1162 static ssize_t trans_stat_show(struct device *dev,
1163 struct device_attribute *attr, char *buf)
1165 struct devfreq *devfreq = to_devfreq(dev);
1168 unsigned int max_state = devfreq->profile->max_state;
1171 return sprintf(buf, "Not Supported.\n");
1173 mutex_lock(&devfreq->lock);
1174 if (!devfreq->stop_polling &&
1175 devfreq_update_status(devfreq, devfreq->previous_freq)) {
1176 mutex_unlock(&devfreq->lock);
1179 mutex_unlock(&devfreq->lock);
1181 len = sprintf(buf, " From : To\n");
1182 len += sprintf(buf + len, " :");
1183 for (i = 0; i < max_state; i++)
1184 len += sprintf(buf + len, "%10lu",
1185 devfreq->profile->freq_table[i]);
1187 len += sprintf(buf + len, " time(ms)\n");
1189 for (i = 0; i < max_state; i++) {
1190 if (devfreq->profile->freq_table[i]
1191 == devfreq->previous_freq) {
1192 len += sprintf(buf + len, "*");
1194 len += sprintf(buf + len, " ");
1196 len += sprintf(buf + len, "%10lu:",
1197 devfreq->profile->freq_table[i]);
1198 for (j = 0; j < max_state; j++)
1199 len += sprintf(buf + len, "%10u",
1200 devfreq->trans_table[(i * max_state) + j]);
1201 len += sprintf(buf + len, "%10u\n",
1202 jiffies_to_msecs(devfreq->time_in_state[i]));
1205 len += sprintf(buf + len, "Total transition : %u\n",
1206 devfreq->total_trans);
1209 static DEVICE_ATTR_RO(trans_stat);
1211 static struct attribute *devfreq_attrs[] = {
1212 &dev_attr_governor.attr,
1213 &dev_attr_available_governors.attr,
1214 &dev_attr_cur_freq.attr,
1215 &dev_attr_available_frequencies.attr,
1216 &dev_attr_target_freq.attr,
1217 &dev_attr_polling_interval.attr,
1218 &dev_attr_min_freq.attr,
1219 &dev_attr_max_freq.attr,
1220 &dev_attr_trans_stat.attr,
1223 ATTRIBUTE_GROUPS(devfreq);
1225 static int __init devfreq_init(void)
1227 devfreq_class = class_create(THIS_MODULE, "devfreq");
1228 if (IS_ERR(devfreq_class)) {
1229 pr_err("%s: couldn't create class\n", __FILE__);
1230 return PTR_ERR(devfreq_class);
1233 devfreq_wq = create_freezable_workqueue("devfreq_wq");
1235 class_destroy(devfreq_class);
1236 pr_err("%s: couldn't create workqueue\n", __FILE__);
1239 devfreq_class->dev_groups = devfreq_groups;
1243 subsys_initcall(devfreq_init);
1246 * The followings are helper functions for devfreq user device drivers with
1251 * devfreq_recommended_opp() - Helper function to get proper OPP for the
1252 * freq value given to target callback.
1253 * @dev: The devfreq user device. (parent of devfreq)
1254 * @freq: The frequency given to target function
1255 * @flags: Flags handed from devfreq framework.
1257 * Locking: This function must be called under rcu_read_lock(). opp is a rcu
1258 * protected pointer. The reason for the same is that the opp pointer which is
1259 * returned will remain valid for use with opp_get_{voltage, freq} only while
1260 * under the locked area. The pointer returned must be used prior to unlocking
1261 * with rcu_read_unlock() to maintain the integrity of the pointer.
1263 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1264 unsigned long *freq,
1267 struct dev_pm_opp *opp;
1269 if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1270 /* The freq is an upper bound. opp should be lower */
1271 opp = dev_pm_opp_find_freq_floor(dev, freq);
1273 /* If not available, use the closest opp */
1274 if (opp == ERR_PTR(-ERANGE))
1275 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1277 /* The freq is an lower bound. opp should be higher */
1278 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1280 /* If not available, use the closest opp */
1281 if (opp == ERR_PTR(-ERANGE))
1282 opp = dev_pm_opp_find_freq_floor(dev, freq);
1287 EXPORT_SYMBOL(devfreq_recommended_opp);
1290 * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1291 * for any changes in the OPP availability
1293 * @dev: The devfreq user device. (parent of devfreq)
1294 * @devfreq: The devfreq object.
1296 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1298 struct srcu_notifier_head *nh;
1302 nh = dev_pm_opp_get_notifier(dev);
1307 ret = srcu_notifier_chain_register(nh, &devfreq->nb);
1311 EXPORT_SYMBOL(devfreq_register_opp_notifier);
1314 * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1315 * notified for any changes in the OPP
1316 * availability changes anymore.
1317 * @dev: The devfreq user device. (parent of devfreq)
1318 * @devfreq: The devfreq object.
1320 * At exit() callback of devfreq_dev_profile, this must be included if
1321 * devfreq_recommended_opp is used.
1323 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1325 struct srcu_notifier_head *nh;
1329 nh = dev_pm_opp_get_notifier(dev);
1334 ret = srcu_notifier_chain_unregister(nh, &devfreq->nb);
1338 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
1340 static void devm_devfreq_opp_release(struct device *dev, void *res)
1342 devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
1346 * devm_ devfreq_register_opp_notifier()
1347 * - Resource-managed devfreq_register_opp_notifier()
1348 * @dev: The devfreq user device. (parent of devfreq)
1349 * @devfreq: The devfreq object.
1351 int devm_devfreq_register_opp_notifier(struct device *dev,
1352 struct devfreq *devfreq)
1354 struct devfreq **ptr;
1357 ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
1361 ret = devfreq_register_opp_notifier(dev, devfreq);
1368 devres_add(dev, ptr);
1372 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
1375 * devm_devfreq_unregister_opp_notifier()
1376 * - Resource-managed devfreq_unregister_opp_notifier()
1377 * @dev: The devfreq user device. (parent of devfreq)
1378 * @devfreq: The devfreq object.
1380 void devm_devfreq_unregister_opp_notifier(struct device *dev,
1381 struct devfreq *devfreq)
1383 WARN_ON(devres_release(dev, devm_devfreq_opp_release,
1384 devm_devfreq_dev_match, devfreq));
1386 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
1389 * devfreq_register_notifier() - Register a driver with devfreq
1390 * @devfreq: The devfreq object.
1391 * @nb: The notifier block to register.
1392 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1394 int devfreq_register_notifier(struct devfreq *devfreq,
1395 struct notifier_block *nb,
1404 case DEVFREQ_TRANSITION_NOTIFIER:
1405 ret = srcu_notifier_chain_register(
1406 &devfreq->transition_notifier_list, nb);
1414 EXPORT_SYMBOL(devfreq_register_notifier);
1417 * devfreq_unregister_notifier() - Unregister a driver with devfreq
1418 * @devfreq: The devfreq object.
1419 * @nb: The notifier block to be unregistered.
1420 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1422 int devfreq_unregister_notifier(struct devfreq *devfreq,
1423 struct notifier_block *nb,
1432 case DEVFREQ_TRANSITION_NOTIFIER:
1433 ret = srcu_notifier_chain_unregister(
1434 &devfreq->transition_notifier_list, nb);
1442 EXPORT_SYMBOL(devfreq_unregister_notifier);
1444 struct devfreq_notifier_devres {
1445 struct devfreq *devfreq;
1446 struct notifier_block *nb;
1450 static void devm_devfreq_notifier_release(struct device *dev, void *res)
1452 struct devfreq_notifier_devres *this = res;
1454 devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
1458 * devm_devfreq_register_notifier()
1459 - Resource-managed devfreq_register_notifier()
1460 * @dev: The devfreq user device. (parent of devfreq)
1461 * @devfreq: The devfreq object.
1462 * @nb: The notifier block to be unregistered.
1463 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1465 int devm_devfreq_register_notifier(struct device *dev,
1466 struct devfreq *devfreq,
1467 struct notifier_block *nb,
1470 struct devfreq_notifier_devres *ptr;
1473 ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
1478 ret = devfreq_register_notifier(devfreq, nb, list);
1484 ptr->devfreq = devfreq;
1487 devres_add(dev, ptr);
1491 EXPORT_SYMBOL(devm_devfreq_register_notifier);
1494 * devm_devfreq_unregister_notifier()
1495 - Resource-managed devfreq_unregister_notifier()
1496 * @dev: The devfreq user device. (parent of devfreq)
1497 * @devfreq: The devfreq object.
1498 * @nb: The notifier block to be unregistered.
1499 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1501 void devm_devfreq_unregister_notifier(struct device *dev,
1502 struct devfreq *devfreq,
1503 struct notifier_block *nb,
1506 WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
1507 devm_devfreq_dev_match, devfreq));
1509 EXPORT_SYMBOL(devm_devfreq_unregister_notifier);