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1/*
2 * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
3 * for Non-CPU Devices.
4 *
5 * Copyright (C) 2011 Samsung Electronics
6 * MyungJoo Ham <myungjoo.ham@samsung.com>
7 *
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.
11 */
12
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>
28#include "governor.h"
29
30static struct class *devfreq_class;
31
32/*
33 * devfreq core provides delayed work based load monitoring helper
34 * functions. Governors can use these or can implement their own
35 * monitoring mechanism.
36 */
37static struct workqueue_struct *devfreq_wq;
38
39/* The list of all device-devfreq governors */
40static LIST_HEAD(devfreq_governor_list);
41/* The list of all device-devfreq */
42static LIST_HEAD(devfreq_list);
43static DEFINE_MUTEX(devfreq_list_lock);
44
45/**
46 * find_device_devfreq() - find devfreq struct using device pointer
47 * @dev: device pointer used to lookup device devfreq.
48 *
49 * Search the list of device devfreqs and return the matched device's
50 * devfreq info. devfreq_list_lock should be held by the caller.
51 */
52static struct devfreq *find_device_devfreq(struct device *dev)
53{
54 struct devfreq *tmp_devfreq;
55
56 if (unlikely(IS_ERR_OR_NULL(dev))) {
57 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
58 return ERR_PTR(-EINVAL);
59 }
60 WARN(!mutex_is_locked(&devfreq_list_lock),
61 "devfreq_list_lock must be locked.");
62
63 list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
64 if (tmp_devfreq->dev.parent == dev)
65 return tmp_devfreq;
66 }
67
68 return ERR_PTR(-ENODEV);
69}
70
71/**
72 * devfreq_get_freq_level() - Lookup freq_table for the frequency
73 * @devfreq: the devfreq instance
74 * @freq: the target frequency
75 */
76static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
77{
78 int lev;
79
80 for (lev = 0; lev < devfreq->profile->max_state; lev++)
81 if (freq == devfreq->profile->freq_table[lev])
82 return lev;
83
84 return -EINVAL;
85}
86
87/**
88 * devfreq_update_status() - Update statistics of devfreq behavior
89 * @devfreq: the devfreq instance
90 * @freq: the update target frequency
91 */
92static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
93{
94 int lev, prev_lev, ret = 0;
95 unsigned long cur_time;
96
97 cur_time = jiffies;
98
99 prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
100 if (prev_lev < 0) {
101 ret = prev_lev;
102 goto out;
103 }
104
105 devfreq->time_in_state[prev_lev] +=
106 cur_time - devfreq->last_stat_updated;
107
108 lev = devfreq_get_freq_level(devfreq, freq);
109 if (lev < 0) {
110 ret = lev;
111 goto out;
112 }
113
114 if (lev != prev_lev) {
115 devfreq->trans_table[(prev_lev *
116 devfreq->profile->max_state) + lev]++;
117 devfreq->total_trans++;
118 }
119
120out:
121 devfreq->last_stat_updated = cur_time;
122 return ret;
123}
124
125/**
126 * find_devfreq_governor() - find devfreq governor from name
127 * @name: name of the governor
128 *
129 * Search the list of devfreq governors and return the matched
130 * governor's pointer. devfreq_list_lock should be held by the caller.
131 */
132static struct devfreq_governor *find_devfreq_governor(const char *name)
133{
134 struct devfreq_governor *tmp_governor;
135
136 if (unlikely(IS_ERR_OR_NULL(name))) {
137 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
138 return ERR_PTR(-EINVAL);
139 }
140 WARN(!mutex_is_locked(&devfreq_list_lock),
141 "devfreq_list_lock must be locked.");
142
143 list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
144 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
145 return tmp_governor;
146 }
147
148 return ERR_PTR(-ENODEV);
149}
150
151/* Load monitoring helper functions for governors use */
152
153/**
154 * update_devfreq() - Reevaluate the device and configure frequency.
155 * @devfreq: the devfreq instance.
156 *
157 * Note: Lock devfreq->lock before calling update_devfreq
158 * This function is exported for governors.
159 */
160int update_devfreq(struct devfreq *devfreq)
161{
162 unsigned long freq;
163 int err = 0;
164 u32 flags = 0;
165
166 if (!mutex_is_locked(&devfreq->lock)) {
167 WARN(true, "devfreq->lock must be locked by the caller.\n");
168 return -EINVAL;
169 }
170
171 if (!devfreq->governor)
172 return -EINVAL;
173
174 /* Reevaluate the proper frequency */
175 err = devfreq->governor->get_target_freq(devfreq, &freq);
176 if (err)
177 return err;
178
179 /*
180 * Adjust the freuqency with user freq and QoS.
181 *
182 * List from the highest proiority
183 * max_freq (probably called by thermal when it's too hot)
184 * min_freq
185 */
186
187 if (devfreq->min_freq && freq < devfreq->min_freq) {
188 freq = devfreq->min_freq;
189 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
190 }
191 if (devfreq->max_freq && freq > devfreq->max_freq) {
192 freq = devfreq->max_freq;
193 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
194 }
195
196 err = devfreq->profile->target(devfreq->dev.parent, &freq, flags);
197 if (err)
198 return err;
199
200 if (devfreq->profile->freq_table)
201 if (devfreq_update_status(devfreq, freq))
202 dev_err(&devfreq->dev,
203 "Couldn't update frequency transition information.\n");
204
205 devfreq->previous_freq = freq;
206 return err;
207}
208EXPORT_SYMBOL(update_devfreq);
209
210/**
211 * devfreq_monitor() - Periodically poll devfreq objects.
212 * @work: the work struct used to run devfreq_monitor periodically.
213 *
214 */
215static void devfreq_monitor(struct work_struct *work)
216{
217 int err;
218 struct devfreq *devfreq = container_of(work,
219 struct devfreq, work.work);
220
221 mutex_lock(&devfreq->lock);
222 err = update_devfreq(devfreq);
223 if (err)
224 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
225
226 queue_delayed_work(devfreq_wq, &devfreq->work,
227 msecs_to_jiffies(devfreq->profile->polling_ms));
228 mutex_unlock(&devfreq->lock);
229}
230
231/**
232 * devfreq_monitor_start() - Start load monitoring of devfreq instance
233 * @devfreq: the devfreq instance.
234 *
235 * Helper function for starting devfreq device load monitoing. By
236 * default delayed work based monitoring is supported. Function
237 * to be called from governor in response to DEVFREQ_GOV_START
238 * event when device is added to devfreq framework.
239 */
240void devfreq_monitor_start(struct devfreq *devfreq)
241{
242 INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
243 if (devfreq->profile->polling_ms)
244 queue_delayed_work(devfreq_wq, &devfreq->work,
245 msecs_to_jiffies(devfreq->profile->polling_ms));
246}
247EXPORT_SYMBOL(devfreq_monitor_start);
248
249/**
250 * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
251 * @devfreq: the devfreq instance.
252 *
253 * Helper function to stop devfreq device load monitoing. Function
254 * to be called from governor in response to DEVFREQ_GOV_STOP
255 * event when device is removed from devfreq framework.
256 */
257void devfreq_monitor_stop(struct devfreq *devfreq)
258{
259 cancel_delayed_work_sync(&devfreq->work);
260}
261EXPORT_SYMBOL(devfreq_monitor_stop);
262
263/**
264 * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
265 * @devfreq: the devfreq instance.
266 *
267 * Helper function to suspend devfreq device load monitoing. Function
268 * to be called from governor in response to DEVFREQ_GOV_SUSPEND
269 * event or when polling interval is set to zero.
270 *
271 * Note: Though this function is same as devfreq_monitor_stop(),
272 * intentionally kept separate to provide hooks for collecting
273 * transition statistics.
274 */
275void devfreq_monitor_suspend(struct devfreq *devfreq)
276{
277 mutex_lock(&devfreq->lock);
278 if (devfreq->stop_polling) {
279 mutex_unlock(&devfreq->lock);
280 return;
281 }
282
283 devfreq_update_status(devfreq, devfreq->previous_freq);
284 devfreq->stop_polling = true;
285 mutex_unlock(&devfreq->lock);
286 cancel_delayed_work_sync(&devfreq->work);
287}
288EXPORT_SYMBOL(devfreq_monitor_suspend);
289
290/**
291 * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
292 * @devfreq: the devfreq instance.
293 *
294 * Helper function to resume devfreq device load monitoing. Function
295 * to be called from governor in response to DEVFREQ_GOV_RESUME
296 * event or when polling interval is set to non-zero.
297 */
298void devfreq_monitor_resume(struct devfreq *devfreq)
299{
300 unsigned long freq;
301
302 mutex_lock(&devfreq->lock);
303 if (!devfreq->stop_polling)
304 goto out;
305
306 if (!delayed_work_pending(&devfreq->work) &&
307 devfreq->profile->polling_ms)
308 queue_delayed_work(devfreq_wq, &devfreq->work,
309 msecs_to_jiffies(devfreq->profile->polling_ms));
310
311 devfreq->last_stat_updated = jiffies;
312 devfreq->stop_polling = false;
313
314 if (devfreq->profile->get_cur_freq &&
315 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
316 devfreq->previous_freq = freq;
317
318out:
319 mutex_unlock(&devfreq->lock);
320}
321EXPORT_SYMBOL(devfreq_monitor_resume);
322
323/**
324 * devfreq_interval_update() - Update device devfreq monitoring interval
325 * @devfreq: the devfreq instance.
326 * @delay: new polling interval to be set.
327 *
328 * Helper function to set new load monitoring polling interval. Function
329 * to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
330 */
331void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
332{
333 unsigned int cur_delay = devfreq->profile->polling_ms;
334 unsigned int new_delay = *delay;
335
336 mutex_lock(&devfreq->lock);
337 devfreq->profile->polling_ms = new_delay;
338
339 if (devfreq->stop_polling)
340 goto out;
341
342 /* if new delay is zero, stop polling */
343 if (!new_delay) {
344 mutex_unlock(&devfreq->lock);
345 cancel_delayed_work_sync(&devfreq->work);
346 return;
347 }
348
349 /* if current delay is zero, start polling with new delay */
350 if (!cur_delay) {
351 queue_delayed_work(devfreq_wq, &devfreq->work,
352 msecs_to_jiffies(devfreq->profile->polling_ms));
353 goto out;
354 }
355
356 /* if current delay is greater than new delay, restart polling */
357 if (cur_delay > new_delay) {
358 mutex_unlock(&devfreq->lock);
359 cancel_delayed_work_sync(&devfreq->work);
360 mutex_lock(&devfreq->lock);
361 if (!devfreq->stop_polling)
362 queue_delayed_work(devfreq_wq, &devfreq->work,
363 msecs_to_jiffies(devfreq->profile->polling_ms));
364 }
365out:
366 mutex_unlock(&devfreq->lock);
367}
368EXPORT_SYMBOL(devfreq_interval_update);
369
370/**
371 * devfreq_notifier_call() - Notify that the device frequency requirements
372 * has been changed out of devfreq framework.
373 * @nb: the notifier_block (supposed to be devfreq->nb)
374 * @type: not used
375 * @devp: not used
376 *
377 * Called by a notifier that uses devfreq->nb.
378 */
379static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
380 void *devp)
381{
382 struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
383 int ret;
384
385 mutex_lock(&devfreq->lock);
386 ret = update_devfreq(devfreq);
387 mutex_unlock(&devfreq->lock);
388
389 return ret;
390}
391
392/**
393 * _remove_devfreq() - Remove devfreq from the list and release its resources.
394 * @devfreq: the devfreq struct
395 * @skip: skip calling device_unregister().
396 */
397static void _remove_devfreq(struct devfreq *devfreq, bool skip)
398{
399 mutex_lock(&devfreq_list_lock);
400 if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) {
401 mutex_unlock(&devfreq_list_lock);
402 dev_warn(&devfreq->dev, "releasing devfreq which doesn't exist\n");
403 return;
404 }
405 list_del(&devfreq->node);
406 mutex_unlock(&devfreq_list_lock);
407
408 if (devfreq->governor)
409 devfreq->governor->event_handler(devfreq,
410 DEVFREQ_GOV_STOP, NULL);
411
412 if (devfreq->profile->exit)
413 devfreq->profile->exit(devfreq->dev.parent);
414
415 if (!skip && get_device(&devfreq->dev)) {
416 device_unregister(&devfreq->dev);
417 put_device(&devfreq->dev);
418 }
419
420 mutex_destroy(&devfreq->lock);
421 kfree(devfreq);
422}
423
424/**
425 * devfreq_dev_release() - Callback for struct device to release the device.
426 * @dev: the devfreq device
427 *
428 * This calls _remove_devfreq() if _remove_devfreq() is not called.
429 * Note that devfreq_dev_release() could be called by _remove_devfreq() as
430 * well as by others unregistering the device.
431 */
432static void devfreq_dev_release(struct device *dev)
433{
434 struct devfreq *devfreq = to_devfreq(dev);
435
436 _remove_devfreq(devfreq, true);
437}
438
439/**
440 * devfreq_add_device() - Add devfreq feature to the device
441 * @dev: the device to add devfreq feature.
442 * @profile: device-specific profile to run devfreq.
443 * @governor_name: name of the policy to choose frequency.
444 * @data: private data for the governor. The devfreq framework does not
445 * touch this value.
446 */
447struct devfreq *devfreq_add_device(struct device *dev,
448 struct devfreq_dev_profile *profile,
449 const char *governor_name,
450 void *data)
451{
452 struct devfreq *devfreq;
453 struct devfreq_governor *governor;
454 int err = 0;
455
456 if (!dev || !profile || !governor_name) {
457 dev_err(dev, "%s: Invalid parameters.\n", __func__);
458 return ERR_PTR(-EINVAL);
459 }
460
461 mutex_lock(&devfreq_list_lock);
462 devfreq = find_device_devfreq(dev);
463 mutex_unlock(&devfreq_list_lock);
464 if (!IS_ERR(devfreq)) {
465 dev_err(dev, "%s: Unable to create devfreq for the device. It already has one.\n", __func__);
466 err = -EINVAL;
467 goto err_out;
468 }
469
470 devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
471 if (!devfreq) {
472 dev_err(dev, "%s: Unable to create devfreq for the device\n",
473 __func__);
474 err = -ENOMEM;
475 goto err_out;
476 }
477
478 mutex_init(&devfreq->lock);
479 mutex_lock(&devfreq->lock);
480 devfreq->dev.parent = dev;
481 devfreq->dev.class = devfreq_class;
482 devfreq->dev.release = devfreq_dev_release;
483 devfreq->profile = profile;
484 strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
485 devfreq->previous_freq = profile->initial_freq;
486 devfreq->data = data;
487 devfreq->nb.notifier_call = devfreq_notifier_call;
488
489 devfreq->trans_table = devm_kzalloc(dev, sizeof(unsigned int) *
490 devfreq->profile->max_state *
491 devfreq->profile->max_state,
492 GFP_KERNEL);
493 devfreq->time_in_state = devm_kzalloc(dev, sizeof(unsigned int) *
494 devfreq->profile->max_state,
495 GFP_KERNEL);
496 devfreq->last_stat_updated = jiffies;
497
498 dev_set_name(&devfreq->dev, "%s", dev_name(dev));
499 err = device_register(&devfreq->dev);
500 if (err) {
501 put_device(&devfreq->dev);
502 mutex_unlock(&devfreq->lock);
503 goto err_dev;
504 }
505
506 mutex_unlock(&devfreq->lock);
507
508 mutex_lock(&devfreq_list_lock);
509 list_add(&devfreq->node, &devfreq_list);
510
511 governor = find_devfreq_governor(devfreq->governor_name);
512 if (!IS_ERR(governor))
513 devfreq->governor = governor;
514 if (devfreq->governor)
515 err = devfreq->governor->event_handler(devfreq,
516 DEVFREQ_GOV_START, NULL);
517 mutex_unlock(&devfreq_list_lock);
518 if (err) {
519 dev_err(dev, "%s: Unable to start governor for the device\n",
520 __func__);
521 goto err_init;
522 }
523
524 return devfreq;
525
526err_init:
527 list_del(&devfreq->node);
528 device_unregister(&devfreq->dev);
529err_dev:
530 kfree(devfreq);
531err_out:
532 return ERR_PTR(err);
533}
534EXPORT_SYMBOL(devfreq_add_device);
535
536/**
537 * devfreq_remove_device() - Remove devfreq feature from a device.
538 * @devfreq: the devfreq instance to be removed
539 *
540 * The opposite of devfreq_add_device().
541 */
542int devfreq_remove_device(struct devfreq *devfreq)
543{
544 if (!devfreq)
545 return -EINVAL;
546
547 _remove_devfreq(devfreq, false);
548
549 return 0;
550}
551EXPORT_SYMBOL(devfreq_remove_device);
552
553/**
554 * devfreq_suspend_device() - Suspend devfreq of a device.
555 * @devfreq: the devfreq instance to be suspended
556 *
557 * This function is intended to be called by the pm callbacks
558 * (e.g., runtime_suspend, suspend) of the device driver that
559 * holds the devfreq.
560 */
561int devfreq_suspend_device(struct devfreq *devfreq)
562{
563 if (!devfreq)
564 return -EINVAL;
565
566 if (!devfreq->governor)
567 return 0;
568
569 return devfreq->governor->event_handler(devfreq,
570 DEVFREQ_GOV_SUSPEND, NULL);
571}
572EXPORT_SYMBOL(devfreq_suspend_device);
573
574/**
575 * devfreq_resume_device() - Resume devfreq of a device.
576 * @devfreq: the devfreq instance to be resumed
577 *
578 * This function is intended to be called by the pm callbacks
579 * (e.g., runtime_resume, resume) of the device driver that
580 * holds the devfreq.
581 */
582int devfreq_resume_device(struct devfreq *devfreq)
583{
584 if (!devfreq)
585 return -EINVAL;
586
587 if (!devfreq->governor)
588 return 0;
589
590 return devfreq->governor->event_handler(devfreq,
591 DEVFREQ_GOV_RESUME, NULL);
592}
593EXPORT_SYMBOL(devfreq_resume_device);
594
595/**
596 * devfreq_add_governor() - Add devfreq governor
597 * @governor: the devfreq governor to be added
598 */
599int devfreq_add_governor(struct devfreq_governor *governor)
600{
601 struct devfreq_governor *g;
602 struct devfreq *devfreq;
603 int err = 0;
604
605 if (!governor) {
606 pr_err("%s: Invalid parameters.\n", __func__);
607 return -EINVAL;
608 }
609
610 mutex_lock(&devfreq_list_lock);
611 g = find_devfreq_governor(governor->name);
612 if (!IS_ERR(g)) {
613 pr_err("%s: governor %s already registered\n", __func__,
614 g->name);
615 err = -EINVAL;
616 goto err_out;
617 }
618
619 list_add(&governor->node, &devfreq_governor_list);
620
621 list_for_each_entry(devfreq, &devfreq_list, node) {
622 int ret = 0;
623 struct device *dev = devfreq->dev.parent;
624
625 if (!strncmp(devfreq->governor_name, governor->name,
626 DEVFREQ_NAME_LEN)) {
627 /* The following should never occur */
628 if (devfreq->governor) {
629 dev_warn(dev,
630 "%s: Governor %s already present\n",
631 __func__, devfreq->governor->name);
632 ret = devfreq->governor->event_handler(devfreq,
633 DEVFREQ_GOV_STOP, NULL);
634 if (ret) {
635 dev_warn(dev,
636 "%s: Governor %s stop = %d\n",
637 __func__,
638 devfreq->governor->name, ret);
639 }
640 /* Fall through */
641 }
642 devfreq->governor = governor;
643 ret = devfreq->governor->event_handler(devfreq,
644 DEVFREQ_GOV_START, NULL);
645 if (ret) {
646 dev_warn(dev, "%s: Governor %s start=%d\n",
647 __func__, devfreq->governor->name,
648 ret);
649 }
650 }
651 }
652
653err_out:
654 mutex_unlock(&devfreq_list_lock);
655
656 return err;
657}
658EXPORT_SYMBOL(devfreq_add_governor);
659
660/**
661 * devfreq_remove_device() - Remove devfreq feature from a device.
662 * @governor: the devfreq governor to be removed
663 */
664int devfreq_remove_governor(struct devfreq_governor *governor)
665{
666 struct devfreq_governor *g;
667 struct devfreq *devfreq;
668 int err = 0;
669
670 if (!governor) {
671 pr_err("%s: Invalid parameters.\n", __func__);
672 return -EINVAL;
673 }
674
675 mutex_lock(&devfreq_list_lock);
676 g = find_devfreq_governor(governor->name);
677 if (IS_ERR(g)) {
678 pr_err("%s: governor %s not registered\n", __func__,
679 governor->name);
680 err = PTR_ERR(g);
681 goto err_out;
682 }
683 list_for_each_entry(devfreq, &devfreq_list, node) {
684 int ret;
685 struct device *dev = devfreq->dev.parent;
686
687 if (!strncmp(devfreq->governor_name, governor->name,
688 DEVFREQ_NAME_LEN)) {
689 /* we should have a devfreq governor! */
690 if (!devfreq->governor) {
691 dev_warn(dev, "%s: Governor %s NOT present\n",
692 __func__, governor->name);
693 continue;
694 /* Fall through */
695 }
696 ret = devfreq->governor->event_handler(devfreq,
697 DEVFREQ_GOV_STOP, NULL);
698 if (ret) {
699 dev_warn(dev, "%s: Governor %s stop=%d\n",
700 __func__, devfreq->governor->name,
701 ret);
702 }
703 devfreq->governor = NULL;
704 }
705 }
706
707 list_del(&governor->node);
708err_out:
709 mutex_unlock(&devfreq_list_lock);
710
711 return err;
712}
713EXPORT_SYMBOL(devfreq_remove_governor);
714
715static ssize_t governor_show(struct device *dev,
716 struct device_attribute *attr, char *buf)
717{
718 if (!to_devfreq(dev)->governor)
719 return -EINVAL;
720
721 return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name);
722}
723
724static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
725 const char *buf, size_t count)
726{
727 struct devfreq *df = to_devfreq(dev);
728 int ret;
729 char str_governor[DEVFREQ_NAME_LEN + 1];
730 struct devfreq_governor *governor;
731
732 ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
733 if (ret != 1)
734 return -EINVAL;
735
736 mutex_lock(&devfreq_list_lock);
737 governor = find_devfreq_governor(str_governor);
738 if (IS_ERR(governor)) {
739 ret = PTR_ERR(governor);
740 goto out;
741 }
742 if (df->governor == governor)
743 goto out;
744
745 if (df->governor) {
746 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
747 if (ret) {
748 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
749 __func__, df->governor->name, ret);
750 goto out;
751 }
752 }
753 df->governor = governor;
754 strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
755 ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
756 if (ret)
757 dev_warn(dev, "%s: Governor %s not started(%d)\n",
758 __func__, df->governor->name, ret);
759out:
760 mutex_unlock(&devfreq_list_lock);
761
762 if (!ret)
763 ret = count;
764 return ret;
765}
766static DEVICE_ATTR_RW(governor);
767
768static ssize_t available_governors_show(struct device *d,
769 struct device_attribute *attr,
770 char *buf)
771{
772 struct devfreq_governor *tmp_governor;
773 ssize_t count = 0;
774
775 mutex_lock(&devfreq_list_lock);
776 list_for_each_entry(tmp_governor, &devfreq_governor_list, node)
777 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
778 "%s ", tmp_governor->name);
779 mutex_unlock(&devfreq_list_lock);
780
781 /* Truncate the trailing space */
782 if (count)
783 count--;
784
785 count += sprintf(&buf[count], "\n");
786
787 return count;
788}
789static DEVICE_ATTR_RO(available_governors);
790
791static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
792 char *buf)
793{
794 unsigned long freq;
795 struct devfreq *devfreq = to_devfreq(dev);
796
797 if (devfreq->profile->get_cur_freq &&
798 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
799 return sprintf(buf, "%lu\n", freq);
800
801 return sprintf(buf, "%lu\n", devfreq->previous_freq);
802}
803static DEVICE_ATTR_RO(cur_freq);
804
805static ssize_t target_freq_show(struct device *dev,
806 struct device_attribute *attr, char *buf)
807{
808 return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
809}
810static DEVICE_ATTR_RO(target_freq);
811
812static ssize_t polling_interval_show(struct device *dev,
813 struct device_attribute *attr, char *buf)
814{
815 return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
816}
817
818static ssize_t polling_interval_store(struct device *dev,
819 struct device_attribute *attr,
820 const char *buf, size_t count)
821{
822 struct devfreq *df = to_devfreq(dev);
823 unsigned int value;
824 int ret;
825
826 if (!df->governor)
827 return -EINVAL;
828
829 ret = sscanf(buf, "%u", &value);
830 if (ret != 1)
831 return -EINVAL;
832
833 df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
834 ret = count;
835
836 return ret;
837}
838static DEVICE_ATTR_RW(polling_interval);
839
840static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
841 const char *buf, size_t count)
842{
843 struct devfreq *df = to_devfreq(dev);
844 unsigned long value;
845 int ret;
846 unsigned long max;
847
848 ret = sscanf(buf, "%lu", &value);
849 if (ret != 1)
850 return -EINVAL;
851
852 mutex_lock(&df->lock);
853 max = df->max_freq;
854 if (value && max && value > max) {
855 ret = -EINVAL;
856 goto unlock;
857 }
858
859 df->min_freq = value;
860 update_devfreq(df);
861 ret = count;
862unlock:
863 mutex_unlock(&df->lock);
864 return ret;
865}
866
867static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
868 char *buf)
869{
870 return sprintf(buf, "%lu\n", to_devfreq(dev)->min_freq);
871}
872
873static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
874 const char *buf, size_t count)
875{
876 struct devfreq *df = to_devfreq(dev);
877 unsigned long value;
878 int ret;
879 unsigned long min;
880
881 ret = sscanf(buf, "%lu", &value);
882 if (ret != 1)
883 return -EINVAL;
884
885 mutex_lock(&df->lock);
886 min = df->min_freq;
887 if (value && min && value < min) {
888 ret = -EINVAL;
889 goto unlock;
890 }
891
892 df->max_freq = value;
893 update_devfreq(df);
894 ret = count;
895unlock:
896 mutex_unlock(&df->lock);
897 return ret;
898}
899static DEVICE_ATTR_RW(min_freq);
900
901static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
902 char *buf)
903{
904 return sprintf(buf, "%lu\n", to_devfreq(dev)->max_freq);
905}
906static DEVICE_ATTR_RW(max_freq);
907
908static ssize_t available_frequencies_show(struct device *d,
909 struct device_attribute *attr,
910 char *buf)
911{
912 struct devfreq *df = to_devfreq(d);
913 struct device *dev = df->dev.parent;
914 struct dev_pm_opp *opp;
915 ssize_t count = 0;
916 unsigned long freq = 0;
917
918 rcu_read_lock();
919 do {
920 opp = dev_pm_opp_find_freq_ceil(dev, &freq);
921 if (IS_ERR(opp))
922 break;
923
924 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
925 "%lu ", freq);
926 freq++;
927 } while (1);
928 rcu_read_unlock();
929
930 /* Truncate the trailing space */
931 if (count)
932 count--;
933
934 count += sprintf(&buf[count], "\n");
935
936 return count;
937}
938static DEVICE_ATTR_RO(available_frequencies);
939
940static ssize_t trans_stat_show(struct device *dev,
941 struct device_attribute *attr, char *buf)
942{
943 struct devfreq *devfreq = to_devfreq(dev);
944 ssize_t len;
945 int i, j;
946 unsigned int max_state = devfreq->profile->max_state;
947
948 if (!devfreq->stop_polling &&
949 devfreq_update_status(devfreq, devfreq->previous_freq))
950 return 0;
951
952 len = sprintf(buf, " From : To\n");
953 len += sprintf(buf + len, " :");
954 for (i = 0; i < max_state; i++)
955 len += sprintf(buf + len, "%8u",
956 devfreq->profile->freq_table[i]);
957
958 len += sprintf(buf + len, " time(ms)\n");
959
960 for (i = 0; i < max_state; i++) {
961 if (devfreq->profile->freq_table[i]
962 == devfreq->previous_freq) {
963 len += sprintf(buf + len, "*");
964 } else {
965 len += sprintf(buf + len, " ");
966 }
967 len += sprintf(buf + len, "%8u:",
968 devfreq->profile->freq_table[i]);
969 for (j = 0; j < max_state; j++)
970 len += sprintf(buf + len, "%8u",
971 devfreq->trans_table[(i * max_state) + j]);
972 len += sprintf(buf + len, "%10u\n",
973 jiffies_to_msecs(devfreq->time_in_state[i]));
974 }
975
976 len += sprintf(buf + len, "Total transition : %u\n",
977 devfreq->total_trans);
978 return len;
979}
980static DEVICE_ATTR_RO(trans_stat);
981
982static struct attribute *devfreq_attrs[] = {
983 &dev_attr_governor.attr,
984 &dev_attr_available_governors.attr,
985 &dev_attr_cur_freq.attr,
986 &dev_attr_available_frequencies.attr,
987 &dev_attr_target_freq.attr,
988 &dev_attr_polling_interval.attr,
989 &dev_attr_min_freq.attr,
990 &dev_attr_max_freq.attr,
991 &dev_attr_trans_stat.attr,
992 NULL,
993};
994ATTRIBUTE_GROUPS(devfreq);
995
996static int __init devfreq_init(void)
997{
998 devfreq_class = class_create(THIS_MODULE, "devfreq");
999 if (IS_ERR(devfreq_class)) {
1000 pr_err("%s: couldn't create class\n", __FILE__);
1001 return PTR_ERR(devfreq_class);
1002 }
1003
1004 devfreq_wq = create_freezable_workqueue("devfreq_wq");
1005 if (!devfreq_wq) {
1006 class_destroy(devfreq_class);
1007 pr_err("%s: couldn't create workqueue\n", __FILE__);
1008 return -ENOMEM;
1009 }
1010 devfreq_class->dev_groups = devfreq_groups;
1011
1012 return 0;
1013}
1014subsys_initcall(devfreq_init);
1015
1016static void __exit devfreq_exit(void)
1017{
1018 class_destroy(devfreq_class);
1019 destroy_workqueue(devfreq_wq);
1020}
1021module_exit(devfreq_exit);
1022
1023/*
1024 * The followings are helper functions for devfreq user device drivers with
1025 * OPP framework.
1026 */
1027
1028/**
1029 * devfreq_recommended_opp() - Helper function to get proper OPP for the
1030 * freq value given to target callback.
1031 * @dev: The devfreq user device. (parent of devfreq)
1032 * @freq: The frequency given to target function
1033 * @flags: Flags handed from devfreq framework.
1034 *
1035 * Locking: This function must be called under rcu_read_lock(). opp is a rcu
1036 * protected pointer. The reason for the same is that the opp pointer which is
1037 * returned will remain valid for use with opp_get_{voltage, freq} only while
1038 * under the locked area. The pointer returned must be used prior to unlocking
1039 * with rcu_read_unlock() to maintain the integrity of the pointer.
1040 */
1041struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1042 unsigned long *freq,
1043 u32 flags)
1044{
1045 struct dev_pm_opp *opp;
1046
1047 if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1048 /* The freq is an upper bound. opp should be lower */
1049 opp = dev_pm_opp_find_freq_floor(dev, freq);
1050
1051 /* If not available, use the closest opp */
1052 if (opp == ERR_PTR(-ERANGE))
1053 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1054 } else {
1055 /* The freq is an lower bound. opp should be higher */
1056 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1057
1058 /* If not available, use the closest opp */
1059 if (opp == ERR_PTR(-ERANGE))
1060 opp = dev_pm_opp_find_freq_floor(dev, freq);
1061 }
1062
1063 return opp;
1064}
1065
1066/**
1067 * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1068 * for any changes in the OPP availability
1069 * changes
1070 * @dev: The devfreq user device. (parent of devfreq)
1071 * @devfreq: The devfreq object.
1072 */
1073int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1074{
1075 struct srcu_notifier_head *nh;
1076 int ret = 0;
1077
1078 rcu_read_lock();
1079 nh = dev_pm_opp_get_notifier(dev);
1080 if (IS_ERR(nh))
1081 ret = PTR_ERR(nh);
1082 rcu_read_unlock();
1083 if (!ret)
1084 ret = srcu_notifier_chain_register(nh, &devfreq->nb);
1085
1086 return ret;
1087}
1088
1089/**
1090 * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1091 * notified for any changes in the OPP
1092 * availability changes anymore.
1093 * @dev: The devfreq user device. (parent of devfreq)
1094 * @devfreq: The devfreq object.
1095 *
1096 * At exit() callback of devfreq_dev_profile, this must be included if
1097 * devfreq_recommended_opp is used.
1098 */
1099int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1100{
1101 struct srcu_notifier_head *nh;
1102 int ret = 0;
1103
1104 rcu_read_lock();
1105 nh = dev_pm_opp_get_notifier(dev);
1106 if (IS_ERR(nh))
1107 ret = PTR_ERR(nh);
1108 rcu_read_unlock();
1109 if (!ret)
1110 ret = srcu_notifier_chain_unregister(nh, &devfreq->nb);
1111
1112 return ret;
1113}
1114
1115MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
1116MODULE_DESCRIPTION("devfreq class support");
1117MODULE_LICENSE("GPL");
1/*
2 * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
3 * for Non-CPU Devices.
4 *
5 * Copyright (C) 2011 Samsung Electronics
6 * MyungJoo Ham <myungjoo.ham@samsung.com>
7 *
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.
11 */
12
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>
28#include "governor.h"
29
30static struct class *devfreq_class;
31
32/*
33 * devfreq core provides delayed work based load monitoring helper
34 * functions. Governors can use these or can implement their own
35 * monitoring mechanism.
36 */
37static struct workqueue_struct *devfreq_wq;
38
39/* The list of all device-devfreq governors */
40static LIST_HEAD(devfreq_governor_list);
41/* The list of all device-devfreq */
42static LIST_HEAD(devfreq_list);
43static DEFINE_MUTEX(devfreq_list_lock);
44
45/**
46 * find_device_devfreq() - find devfreq struct using device pointer
47 * @dev: device pointer used to lookup device devfreq.
48 *
49 * Search the list of device devfreqs and return the matched device's
50 * devfreq info. devfreq_list_lock should be held by the caller.
51 */
52static struct devfreq *find_device_devfreq(struct device *dev)
53{
54 struct devfreq *tmp_devfreq;
55
56 if (IS_ERR_OR_NULL(dev)) {
57 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
58 return ERR_PTR(-EINVAL);
59 }
60 WARN(!mutex_is_locked(&devfreq_list_lock),
61 "devfreq_list_lock must be locked.");
62
63 list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
64 if (tmp_devfreq->dev.parent == dev)
65 return tmp_devfreq;
66 }
67
68 return ERR_PTR(-ENODEV);
69}
70
71/**
72 * devfreq_get_freq_level() - Lookup freq_table for the frequency
73 * @devfreq: the devfreq instance
74 * @freq: the target frequency
75 */
76static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
77{
78 int lev;
79
80 for (lev = 0; lev < devfreq->profile->max_state; lev++)
81 if (freq == devfreq->profile->freq_table[lev])
82 return lev;
83
84 return -EINVAL;
85}
86
87/**
88 * devfreq_set_freq_table() - Initialize freq_table for the frequency
89 * @devfreq: the devfreq instance
90 */
91static void devfreq_set_freq_table(struct devfreq *devfreq)
92{
93 struct devfreq_dev_profile *profile = devfreq->profile;
94 struct dev_pm_opp *opp;
95 unsigned long freq;
96 int i, count;
97
98 /* Initialize the freq_table from OPP table */
99 count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
100 if (count <= 0)
101 return;
102
103 profile->max_state = count;
104 profile->freq_table = devm_kcalloc(devfreq->dev.parent,
105 profile->max_state,
106 sizeof(*profile->freq_table),
107 GFP_KERNEL);
108 if (!profile->freq_table) {
109 profile->max_state = 0;
110 return;
111 }
112
113 rcu_read_lock();
114 for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
115 opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
116 if (IS_ERR(opp)) {
117 devm_kfree(devfreq->dev.parent, profile->freq_table);
118 profile->max_state = 0;
119 rcu_read_unlock();
120 return;
121 }
122 profile->freq_table[i] = freq;
123 }
124 rcu_read_unlock();
125}
126
127/**
128 * devfreq_update_status() - Update statistics of devfreq behavior
129 * @devfreq: the devfreq instance
130 * @freq: the update target frequency
131 */
132static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
133{
134 int lev, prev_lev, ret = 0;
135 unsigned long cur_time;
136
137 cur_time = jiffies;
138
139 prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
140 if (prev_lev < 0) {
141 ret = prev_lev;
142 goto out;
143 }
144
145 devfreq->time_in_state[prev_lev] +=
146 cur_time - devfreq->last_stat_updated;
147
148 lev = devfreq_get_freq_level(devfreq, freq);
149 if (lev < 0) {
150 ret = lev;
151 goto out;
152 }
153
154 if (lev != prev_lev) {
155 devfreq->trans_table[(prev_lev *
156 devfreq->profile->max_state) + lev]++;
157 devfreq->total_trans++;
158 }
159
160out:
161 devfreq->last_stat_updated = cur_time;
162 return ret;
163}
164
165/**
166 * find_devfreq_governor() - find devfreq governor from name
167 * @name: name of the governor
168 *
169 * Search the list of devfreq governors and return the matched
170 * governor's pointer. devfreq_list_lock should be held by the caller.
171 */
172static struct devfreq_governor *find_devfreq_governor(const char *name)
173{
174 struct devfreq_governor *tmp_governor;
175
176 if (IS_ERR_OR_NULL(name)) {
177 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
178 return ERR_PTR(-EINVAL);
179 }
180 WARN(!mutex_is_locked(&devfreq_list_lock),
181 "devfreq_list_lock must be locked.");
182
183 list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
184 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
185 return tmp_governor;
186 }
187
188 return ERR_PTR(-ENODEV);
189}
190
191/* Load monitoring helper functions for governors use */
192
193/**
194 * update_devfreq() - Reevaluate the device and configure frequency.
195 * @devfreq: the devfreq instance.
196 *
197 * Note: Lock devfreq->lock before calling update_devfreq
198 * This function is exported for governors.
199 */
200int update_devfreq(struct devfreq *devfreq)
201{
202 unsigned long freq;
203 int err = 0;
204 u32 flags = 0;
205
206 if (!mutex_is_locked(&devfreq->lock)) {
207 WARN(true, "devfreq->lock must be locked by the caller.\n");
208 return -EINVAL;
209 }
210
211 if (!devfreq->governor)
212 return -EINVAL;
213
214 /* Reevaluate the proper frequency */
215 err = devfreq->governor->get_target_freq(devfreq, &freq);
216 if (err)
217 return err;
218
219 /*
220 * Adjust the frequency with user freq and QoS.
221 *
222 * List from the highest priority
223 * max_freq
224 * min_freq
225 */
226
227 if (devfreq->min_freq && freq < devfreq->min_freq) {
228 freq = devfreq->min_freq;
229 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
230 }
231 if (devfreq->max_freq && freq > devfreq->max_freq) {
232 freq = devfreq->max_freq;
233 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
234 }
235
236 err = devfreq->profile->target(devfreq->dev.parent, &freq, flags);
237 if (err)
238 return err;
239
240 if (devfreq->profile->freq_table)
241 if (devfreq_update_status(devfreq, freq))
242 dev_err(&devfreq->dev,
243 "Couldn't update frequency transition information.\n");
244
245 devfreq->previous_freq = freq;
246 return err;
247}
248EXPORT_SYMBOL(update_devfreq);
249
250/**
251 * devfreq_monitor() - Periodically poll devfreq objects.
252 * @work: the work struct used to run devfreq_monitor periodically.
253 *
254 */
255static void devfreq_monitor(struct work_struct *work)
256{
257 int err;
258 struct devfreq *devfreq = container_of(work,
259 struct devfreq, work.work);
260
261 mutex_lock(&devfreq->lock);
262 err = update_devfreq(devfreq);
263 if (err)
264 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
265
266 queue_delayed_work(devfreq_wq, &devfreq->work,
267 msecs_to_jiffies(devfreq->profile->polling_ms));
268 mutex_unlock(&devfreq->lock);
269}
270
271/**
272 * devfreq_monitor_start() - Start load monitoring of devfreq instance
273 * @devfreq: the devfreq instance.
274 *
275 * Helper function for starting devfreq device load monitoing. By
276 * default delayed work based monitoring is supported. Function
277 * to be called from governor in response to DEVFREQ_GOV_START
278 * event when device is added to devfreq framework.
279 */
280void devfreq_monitor_start(struct devfreq *devfreq)
281{
282 INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
283 if (devfreq->profile->polling_ms)
284 queue_delayed_work(devfreq_wq, &devfreq->work,
285 msecs_to_jiffies(devfreq->profile->polling_ms));
286}
287EXPORT_SYMBOL(devfreq_monitor_start);
288
289/**
290 * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
291 * @devfreq: the devfreq instance.
292 *
293 * Helper function to stop devfreq device load monitoing. Function
294 * to be called from governor in response to DEVFREQ_GOV_STOP
295 * event when device is removed from devfreq framework.
296 */
297void devfreq_monitor_stop(struct devfreq *devfreq)
298{
299 cancel_delayed_work_sync(&devfreq->work);
300}
301EXPORT_SYMBOL(devfreq_monitor_stop);
302
303/**
304 * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
305 * @devfreq: the devfreq instance.
306 *
307 * Helper function to suspend devfreq device load monitoing. Function
308 * to be called from governor in response to DEVFREQ_GOV_SUSPEND
309 * event or when polling interval is set to zero.
310 *
311 * Note: Though this function is same as devfreq_monitor_stop(),
312 * intentionally kept separate to provide hooks for collecting
313 * transition statistics.
314 */
315void devfreq_monitor_suspend(struct devfreq *devfreq)
316{
317 mutex_lock(&devfreq->lock);
318 if (devfreq->stop_polling) {
319 mutex_unlock(&devfreq->lock);
320 return;
321 }
322
323 devfreq_update_status(devfreq, devfreq->previous_freq);
324 devfreq->stop_polling = true;
325 mutex_unlock(&devfreq->lock);
326 cancel_delayed_work_sync(&devfreq->work);
327}
328EXPORT_SYMBOL(devfreq_monitor_suspend);
329
330/**
331 * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
332 * @devfreq: the devfreq instance.
333 *
334 * Helper function to resume devfreq device load monitoing. Function
335 * to be called from governor in response to DEVFREQ_GOV_RESUME
336 * event or when polling interval is set to non-zero.
337 */
338void devfreq_monitor_resume(struct devfreq *devfreq)
339{
340 unsigned long freq;
341
342 mutex_lock(&devfreq->lock);
343 if (!devfreq->stop_polling)
344 goto out;
345
346 if (!delayed_work_pending(&devfreq->work) &&
347 devfreq->profile->polling_ms)
348 queue_delayed_work(devfreq_wq, &devfreq->work,
349 msecs_to_jiffies(devfreq->profile->polling_ms));
350
351 devfreq->last_stat_updated = jiffies;
352 devfreq->stop_polling = false;
353
354 if (devfreq->profile->get_cur_freq &&
355 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
356 devfreq->previous_freq = freq;
357
358out:
359 mutex_unlock(&devfreq->lock);
360}
361EXPORT_SYMBOL(devfreq_monitor_resume);
362
363/**
364 * devfreq_interval_update() - Update device devfreq monitoring interval
365 * @devfreq: the devfreq instance.
366 * @delay: new polling interval to be set.
367 *
368 * Helper function to set new load monitoring polling interval. Function
369 * to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
370 */
371void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
372{
373 unsigned int cur_delay = devfreq->profile->polling_ms;
374 unsigned int new_delay = *delay;
375
376 mutex_lock(&devfreq->lock);
377 devfreq->profile->polling_ms = new_delay;
378
379 if (devfreq->stop_polling)
380 goto out;
381
382 /* if new delay is zero, stop polling */
383 if (!new_delay) {
384 mutex_unlock(&devfreq->lock);
385 cancel_delayed_work_sync(&devfreq->work);
386 return;
387 }
388
389 /* if current delay is zero, start polling with new delay */
390 if (!cur_delay) {
391 queue_delayed_work(devfreq_wq, &devfreq->work,
392 msecs_to_jiffies(devfreq->profile->polling_ms));
393 goto out;
394 }
395
396 /* if current delay is greater than new delay, restart polling */
397 if (cur_delay > new_delay) {
398 mutex_unlock(&devfreq->lock);
399 cancel_delayed_work_sync(&devfreq->work);
400 mutex_lock(&devfreq->lock);
401 if (!devfreq->stop_polling)
402 queue_delayed_work(devfreq_wq, &devfreq->work,
403 msecs_to_jiffies(devfreq->profile->polling_ms));
404 }
405out:
406 mutex_unlock(&devfreq->lock);
407}
408EXPORT_SYMBOL(devfreq_interval_update);
409
410/**
411 * devfreq_notifier_call() - Notify that the device frequency requirements
412 * has been changed out of devfreq framework.
413 * @nb: the notifier_block (supposed to be devfreq->nb)
414 * @type: not used
415 * @devp: not used
416 *
417 * Called by a notifier that uses devfreq->nb.
418 */
419static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
420 void *devp)
421{
422 struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
423 int ret;
424
425 mutex_lock(&devfreq->lock);
426 ret = update_devfreq(devfreq);
427 mutex_unlock(&devfreq->lock);
428
429 return ret;
430}
431
432/**
433 * _remove_devfreq() - Remove devfreq from the list and release its resources.
434 * @devfreq: the devfreq struct
435 */
436static void _remove_devfreq(struct devfreq *devfreq)
437{
438 mutex_lock(&devfreq_list_lock);
439 if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) {
440 mutex_unlock(&devfreq_list_lock);
441 dev_warn(&devfreq->dev, "releasing devfreq which doesn't exist\n");
442 return;
443 }
444 list_del(&devfreq->node);
445 mutex_unlock(&devfreq_list_lock);
446
447 if (devfreq->governor)
448 devfreq->governor->event_handler(devfreq,
449 DEVFREQ_GOV_STOP, NULL);
450
451 if (devfreq->profile->exit)
452 devfreq->profile->exit(devfreq->dev.parent);
453
454 mutex_destroy(&devfreq->lock);
455 kfree(devfreq);
456}
457
458/**
459 * devfreq_dev_release() - Callback for struct device to release the device.
460 * @dev: the devfreq device
461 *
462 * This calls _remove_devfreq() if _remove_devfreq() is not called.
463 */
464static void devfreq_dev_release(struct device *dev)
465{
466 struct devfreq *devfreq = to_devfreq(dev);
467
468 _remove_devfreq(devfreq);
469}
470
471/**
472 * devfreq_add_device() - Add devfreq feature to the device
473 * @dev: the device to add devfreq feature.
474 * @profile: device-specific profile to run devfreq.
475 * @governor_name: name of the policy to choose frequency.
476 * @data: private data for the governor. The devfreq framework does not
477 * touch this value.
478 */
479struct devfreq *devfreq_add_device(struct device *dev,
480 struct devfreq_dev_profile *profile,
481 const char *governor_name,
482 void *data)
483{
484 struct devfreq *devfreq;
485 struct devfreq_governor *governor;
486 int err = 0;
487
488 if (!dev || !profile || !governor_name) {
489 dev_err(dev, "%s: Invalid parameters.\n", __func__);
490 return ERR_PTR(-EINVAL);
491 }
492
493 mutex_lock(&devfreq_list_lock);
494 devfreq = find_device_devfreq(dev);
495 mutex_unlock(&devfreq_list_lock);
496 if (!IS_ERR(devfreq)) {
497 dev_err(dev, "%s: Unable to create devfreq for the device. It already has one.\n", __func__);
498 err = -EINVAL;
499 goto err_out;
500 }
501
502 devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
503 if (!devfreq) {
504 dev_err(dev, "%s: Unable to create devfreq for the device\n",
505 __func__);
506 err = -ENOMEM;
507 goto err_out;
508 }
509
510 mutex_init(&devfreq->lock);
511 mutex_lock(&devfreq->lock);
512 devfreq->dev.parent = dev;
513 devfreq->dev.class = devfreq_class;
514 devfreq->dev.release = devfreq_dev_release;
515 devfreq->profile = profile;
516 strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
517 devfreq->previous_freq = profile->initial_freq;
518 devfreq->data = data;
519 devfreq->nb.notifier_call = devfreq_notifier_call;
520
521 if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
522 mutex_unlock(&devfreq->lock);
523 devfreq_set_freq_table(devfreq);
524 mutex_lock(&devfreq->lock);
525 }
526
527 devfreq->trans_table = devm_kzalloc(dev, sizeof(unsigned int) *
528 devfreq->profile->max_state *
529 devfreq->profile->max_state,
530 GFP_KERNEL);
531 devfreq->time_in_state = devm_kzalloc(dev, sizeof(unsigned long) *
532 devfreq->profile->max_state,
533 GFP_KERNEL);
534 devfreq->last_stat_updated = jiffies;
535
536 dev_set_name(&devfreq->dev, "%s", dev_name(dev));
537 err = device_register(&devfreq->dev);
538 if (err) {
539 put_device(&devfreq->dev);
540 mutex_unlock(&devfreq->lock);
541 goto err_out;
542 }
543
544 mutex_unlock(&devfreq->lock);
545
546 mutex_lock(&devfreq_list_lock);
547 list_add(&devfreq->node, &devfreq_list);
548
549 governor = find_devfreq_governor(devfreq->governor_name);
550 if (!IS_ERR(governor))
551 devfreq->governor = governor;
552 if (devfreq->governor)
553 err = devfreq->governor->event_handler(devfreq,
554 DEVFREQ_GOV_START, NULL);
555 mutex_unlock(&devfreq_list_lock);
556 if (err) {
557 dev_err(dev, "%s: Unable to start governor for the device\n",
558 __func__);
559 goto err_init;
560 }
561
562 return devfreq;
563
564err_init:
565 list_del(&devfreq->node);
566 device_unregister(&devfreq->dev);
567 kfree(devfreq);
568err_out:
569 return ERR_PTR(err);
570}
571EXPORT_SYMBOL(devfreq_add_device);
572
573/**
574 * devfreq_remove_device() - Remove devfreq feature from a device.
575 * @devfreq: the devfreq instance to be removed
576 *
577 * The opposite of devfreq_add_device().
578 */
579int devfreq_remove_device(struct devfreq *devfreq)
580{
581 if (!devfreq)
582 return -EINVAL;
583
584 device_unregister(&devfreq->dev);
585 put_device(&devfreq->dev);
586
587 return 0;
588}
589EXPORT_SYMBOL(devfreq_remove_device);
590
591static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
592{
593 struct devfreq **r = res;
594
595 if (WARN_ON(!r || !*r))
596 return 0;
597
598 return *r == data;
599}
600
601static void devm_devfreq_dev_release(struct device *dev, void *res)
602{
603 devfreq_remove_device(*(struct devfreq **)res);
604}
605
606/**
607 * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
608 * @dev: the device to add devfreq feature.
609 * @profile: device-specific profile to run devfreq.
610 * @governor_name: name of the policy to choose frequency.
611 * @data: private data for the governor. The devfreq framework does not
612 * touch this value.
613 *
614 * This function manages automatically the memory of devfreq device using device
615 * resource management and simplify the free operation for memory of devfreq
616 * device.
617 */
618struct devfreq *devm_devfreq_add_device(struct device *dev,
619 struct devfreq_dev_profile *profile,
620 const char *governor_name,
621 void *data)
622{
623 struct devfreq **ptr, *devfreq;
624
625 ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
626 if (!ptr)
627 return ERR_PTR(-ENOMEM);
628
629 devfreq = devfreq_add_device(dev, profile, governor_name, data);
630 if (IS_ERR(devfreq)) {
631 devres_free(ptr);
632 return ERR_PTR(-ENOMEM);
633 }
634
635 *ptr = devfreq;
636 devres_add(dev, ptr);
637
638 return devfreq;
639}
640EXPORT_SYMBOL(devm_devfreq_add_device);
641
642/**
643 * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
644 * @dev: the device to add devfreq feature.
645 * @devfreq: the devfreq instance to be removed
646 */
647void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
648{
649 WARN_ON(devres_release(dev, devm_devfreq_dev_release,
650 devm_devfreq_dev_match, devfreq));
651}
652EXPORT_SYMBOL(devm_devfreq_remove_device);
653
654/**
655 * devfreq_suspend_device() - Suspend devfreq of a device.
656 * @devfreq: the devfreq instance to be suspended
657 *
658 * This function is intended to be called by the pm callbacks
659 * (e.g., runtime_suspend, suspend) of the device driver that
660 * holds the devfreq.
661 */
662int devfreq_suspend_device(struct devfreq *devfreq)
663{
664 if (!devfreq)
665 return -EINVAL;
666
667 if (!devfreq->governor)
668 return 0;
669
670 return devfreq->governor->event_handler(devfreq,
671 DEVFREQ_GOV_SUSPEND, NULL);
672}
673EXPORT_SYMBOL(devfreq_suspend_device);
674
675/**
676 * devfreq_resume_device() - Resume devfreq of a device.
677 * @devfreq: the devfreq instance to be resumed
678 *
679 * This function is intended to be called by the pm callbacks
680 * (e.g., runtime_resume, resume) of the device driver that
681 * holds the devfreq.
682 */
683int devfreq_resume_device(struct devfreq *devfreq)
684{
685 if (!devfreq)
686 return -EINVAL;
687
688 if (!devfreq->governor)
689 return 0;
690
691 return devfreq->governor->event_handler(devfreq,
692 DEVFREQ_GOV_RESUME, NULL);
693}
694EXPORT_SYMBOL(devfreq_resume_device);
695
696/**
697 * devfreq_add_governor() - Add devfreq governor
698 * @governor: the devfreq governor to be added
699 */
700int devfreq_add_governor(struct devfreq_governor *governor)
701{
702 struct devfreq_governor *g;
703 struct devfreq *devfreq;
704 int err = 0;
705
706 if (!governor) {
707 pr_err("%s: Invalid parameters.\n", __func__);
708 return -EINVAL;
709 }
710
711 mutex_lock(&devfreq_list_lock);
712 g = find_devfreq_governor(governor->name);
713 if (!IS_ERR(g)) {
714 pr_err("%s: governor %s already registered\n", __func__,
715 g->name);
716 err = -EINVAL;
717 goto err_out;
718 }
719
720 list_add(&governor->node, &devfreq_governor_list);
721
722 list_for_each_entry(devfreq, &devfreq_list, node) {
723 int ret = 0;
724 struct device *dev = devfreq->dev.parent;
725
726 if (!strncmp(devfreq->governor_name, governor->name,
727 DEVFREQ_NAME_LEN)) {
728 /* The following should never occur */
729 if (devfreq->governor) {
730 dev_warn(dev,
731 "%s: Governor %s already present\n",
732 __func__, devfreq->governor->name);
733 ret = devfreq->governor->event_handler(devfreq,
734 DEVFREQ_GOV_STOP, NULL);
735 if (ret) {
736 dev_warn(dev,
737 "%s: Governor %s stop = %d\n",
738 __func__,
739 devfreq->governor->name, ret);
740 }
741 /* Fall through */
742 }
743 devfreq->governor = governor;
744 ret = devfreq->governor->event_handler(devfreq,
745 DEVFREQ_GOV_START, NULL);
746 if (ret) {
747 dev_warn(dev, "%s: Governor %s start=%d\n",
748 __func__, devfreq->governor->name,
749 ret);
750 }
751 }
752 }
753
754err_out:
755 mutex_unlock(&devfreq_list_lock);
756
757 return err;
758}
759EXPORT_SYMBOL(devfreq_add_governor);
760
761/**
762 * devfreq_remove_device() - Remove devfreq feature from a device.
763 * @governor: the devfreq governor to be removed
764 */
765int devfreq_remove_governor(struct devfreq_governor *governor)
766{
767 struct devfreq_governor *g;
768 struct devfreq *devfreq;
769 int err = 0;
770
771 if (!governor) {
772 pr_err("%s: Invalid parameters.\n", __func__);
773 return -EINVAL;
774 }
775
776 mutex_lock(&devfreq_list_lock);
777 g = find_devfreq_governor(governor->name);
778 if (IS_ERR(g)) {
779 pr_err("%s: governor %s not registered\n", __func__,
780 governor->name);
781 err = PTR_ERR(g);
782 goto err_out;
783 }
784 list_for_each_entry(devfreq, &devfreq_list, node) {
785 int ret;
786 struct device *dev = devfreq->dev.parent;
787
788 if (!strncmp(devfreq->governor_name, governor->name,
789 DEVFREQ_NAME_LEN)) {
790 /* we should have a devfreq governor! */
791 if (!devfreq->governor) {
792 dev_warn(dev, "%s: Governor %s NOT present\n",
793 __func__, governor->name);
794 continue;
795 /* Fall through */
796 }
797 ret = devfreq->governor->event_handler(devfreq,
798 DEVFREQ_GOV_STOP, NULL);
799 if (ret) {
800 dev_warn(dev, "%s: Governor %s stop=%d\n",
801 __func__, devfreq->governor->name,
802 ret);
803 }
804 devfreq->governor = NULL;
805 }
806 }
807
808 list_del(&governor->node);
809err_out:
810 mutex_unlock(&devfreq_list_lock);
811
812 return err;
813}
814EXPORT_SYMBOL(devfreq_remove_governor);
815
816static ssize_t governor_show(struct device *dev,
817 struct device_attribute *attr, char *buf)
818{
819 if (!to_devfreq(dev)->governor)
820 return -EINVAL;
821
822 return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name);
823}
824
825static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
826 const char *buf, size_t count)
827{
828 struct devfreq *df = to_devfreq(dev);
829 int ret;
830 char str_governor[DEVFREQ_NAME_LEN + 1];
831 struct devfreq_governor *governor;
832
833 ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
834 if (ret != 1)
835 return -EINVAL;
836
837 mutex_lock(&devfreq_list_lock);
838 governor = find_devfreq_governor(str_governor);
839 if (IS_ERR(governor)) {
840 ret = PTR_ERR(governor);
841 goto out;
842 }
843 if (df->governor == governor) {
844 ret = 0;
845 goto out;
846 }
847
848 if (df->governor) {
849 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
850 if (ret) {
851 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
852 __func__, df->governor->name, ret);
853 goto out;
854 }
855 }
856 df->governor = governor;
857 strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
858 ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
859 if (ret)
860 dev_warn(dev, "%s: Governor %s not started(%d)\n",
861 __func__, df->governor->name, ret);
862out:
863 mutex_unlock(&devfreq_list_lock);
864
865 if (!ret)
866 ret = count;
867 return ret;
868}
869static DEVICE_ATTR_RW(governor);
870
871static ssize_t available_governors_show(struct device *d,
872 struct device_attribute *attr,
873 char *buf)
874{
875 struct devfreq_governor *tmp_governor;
876 ssize_t count = 0;
877
878 mutex_lock(&devfreq_list_lock);
879 list_for_each_entry(tmp_governor, &devfreq_governor_list, node)
880 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
881 "%s ", tmp_governor->name);
882 mutex_unlock(&devfreq_list_lock);
883
884 /* Truncate the trailing space */
885 if (count)
886 count--;
887
888 count += sprintf(&buf[count], "\n");
889
890 return count;
891}
892static DEVICE_ATTR_RO(available_governors);
893
894static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
895 char *buf)
896{
897 unsigned long freq;
898 struct devfreq *devfreq = to_devfreq(dev);
899
900 if (devfreq->profile->get_cur_freq &&
901 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
902 return sprintf(buf, "%lu\n", freq);
903
904 return sprintf(buf, "%lu\n", devfreq->previous_freq);
905}
906static DEVICE_ATTR_RO(cur_freq);
907
908static ssize_t target_freq_show(struct device *dev,
909 struct device_attribute *attr, char *buf)
910{
911 return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
912}
913static DEVICE_ATTR_RO(target_freq);
914
915static ssize_t polling_interval_show(struct device *dev,
916 struct device_attribute *attr, char *buf)
917{
918 return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
919}
920
921static ssize_t polling_interval_store(struct device *dev,
922 struct device_attribute *attr,
923 const char *buf, size_t count)
924{
925 struct devfreq *df = to_devfreq(dev);
926 unsigned int value;
927 int ret;
928
929 if (!df->governor)
930 return -EINVAL;
931
932 ret = sscanf(buf, "%u", &value);
933 if (ret != 1)
934 return -EINVAL;
935
936 df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
937 ret = count;
938
939 return ret;
940}
941static DEVICE_ATTR_RW(polling_interval);
942
943static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
944 const char *buf, size_t count)
945{
946 struct devfreq *df = to_devfreq(dev);
947 unsigned long value;
948 int ret;
949 unsigned long max;
950
951 ret = sscanf(buf, "%lu", &value);
952 if (ret != 1)
953 return -EINVAL;
954
955 mutex_lock(&df->lock);
956 max = df->max_freq;
957 if (value && max && value > max) {
958 ret = -EINVAL;
959 goto unlock;
960 }
961
962 df->min_freq = value;
963 update_devfreq(df);
964 ret = count;
965unlock:
966 mutex_unlock(&df->lock);
967 return ret;
968}
969
970static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
971 const char *buf, size_t count)
972{
973 struct devfreq *df = to_devfreq(dev);
974 unsigned long value;
975 int ret;
976 unsigned long min;
977
978 ret = sscanf(buf, "%lu", &value);
979 if (ret != 1)
980 return -EINVAL;
981
982 mutex_lock(&df->lock);
983 min = df->min_freq;
984 if (value && min && value < min) {
985 ret = -EINVAL;
986 goto unlock;
987 }
988
989 df->max_freq = value;
990 update_devfreq(df);
991 ret = count;
992unlock:
993 mutex_unlock(&df->lock);
994 return ret;
995}
996
997#define show_one(name) \
998static ssize_t name##_show \
999(struct device *dev, struct device_attribute *attr, char *buf) \
1000{ \
1001 return sprintf(buf, "%lu\n", to_devfreq(dev)->name); \
1002}
1003show_one(min_freq);
1004show_one(max_freq);
1005
1006static DEVICE_ATTR_RW(min_freq);
1007static DEVICE_ATTR_RW(max_freq);
1008
1009static ssize_t available_frequencies_show(struct device *d,
1010 struct device_attribute *attr,
1011 char *buf)
1012{
1013 struct devfreq *df = to_devfreq(d);
1014 struct device *dev = df->dev.parent;
1015 struct dev_pm_opp *opp;
1016 ssize_t count = 0;
1017 unsigned long freq = 0;
1018
1019 rcu_read_lock();
1020 do {
1021 opp = dev_pm_opp_find_freq_ceil(dev, &freq);
1022 if (IS_ERR(opp))
1023 break;
1024
1025 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1026 "%lu ", freq);
1027 freq++;
1028 } while (1);
1029 rcu_read_unlock();
1030
1031 /* Truncate the trailing space */
1032 if (count)
1033 count--;
1034
1035 count += sprintf(&buf[count], "\n");
1036
1037 return count;
1038}
1039static DEVICE_ATTR_RO(available_frequencies);
1040
1041static ssize_t trans_stat_show(struct device *dev,
1042 struct device_attribute *attr, char *buf)
1043{
1044 struct devfreq *devfreq = to_devfreq(dev);
1045 ssize_t len;
1046 int i, j;
1047 unsigned int max_state = devfreq->profile->max_state;
1048
1049 if (!devfreq->stop_polling &&
1050 devfreq_update_status(devfreq, devfreq->previous_freq))
1051 return 0;
1052 if (max_state == 0)
1053 return sprintf(buf, "Not Supported.\n");
1054
1055 len = sprintf(buf, " From : To\n");
1056 len += sprintf(buf + len, " :");
1057 for (i = 0; i < max_state; i++)
1058 len += sprintf(buf + len, "%10lu",
1059 devfreq->profile->freq_table[i]);
1060
1061 len += sprintf(buf + len, " time(ms)\n");
1062
1063 for (i = 0; i < max_state; i++) {
1064 if (devfreq->profile->freq_table[i]
1065 == devfreq->previous_freq) {
1066 len += sprintf(buf + len, "*");
1067 } else {
1068 len += sprintf(buf + len, " ");
1069 }
1070 len += sprintf(buf + len, "%10lu:",
1071 devfreq->profile->freq_table[i]);
1072 for (j = 0; j < max_state; j++)
1073 len += sprintf(buf + len, "%10u",
1074 devfreq->trans_table[(i * max_state) + j]);
1075 len += sprintf(buf + len, "%10u\n",
1076 jiffies_to_msecs(devfreq->time_in_state[i]));
1077 }
1078
1079 len += sprintf(buf + len, "Total transition : %u\n",
1080 devfreq->total_trans);
1081 return len;
1082}
1083static DEVICE_ATTR_RO(trans_stat);
1084
1085static struct attribute *devfreq_attrs[] = {
1086 &dev_attr_governor.attr,
1087 &dev_attr_available_governors.attr,
1088 &dev_attr_cur_freq.attr,
1089 &dev_attr_available_frequencies.attr,
1090 &dev_attr_target_freq.attr,
1091 &dev_attr_polling_interval.attr,
1092 &dev_attr_min_freq.attr,
1093 &dev_attr_max_freq.attr,
1094 &dev_attr_trans_stat.attr,
1095 NULL,
1096};
1097ATTRIBUTE_GROUPS(devfreq);
1098
1099static int __init devfreq_init(void)
1100{
1101 devfreq_class = class_create(THIS_MODULE, "devfreq");
1102 if (IS_ERR(devfreq_class)) {
1103 pr_err("%s: couldn't create class\n", __FILE__);
1104 return PTR_ERR(devfreq_class);
1105 }
1106
1107 devfreq_wq = create_freezable_workqueue("devfreq_wq");
1108 if (!devfreq_wq) {
1109 class_destroy(devfreq_class);
1110 pr_err("%s: couldn't create workqueue\n", __FILE__);
1111 return -ENOMEM;
1112 }
1113 devfreq_class->dev_groups = devfreq_groups;
1114
1115 return 0;
1116}
1117subsys_initcall(devfreq_init);
1118
1119static void __exit devfreq_exit(void)
1120{
1121 class_destroy(devfreq_class);
1122 destroy_workqueue(devfreq_wq);
1123}
1124module_exit(devfreq_exit);
1125
1126/*
1127 * The followings are helper functions for devfreq user device drivers with
1128 * OPP framework.
1129 */
1130
1131/**
1132 * devfreq_recommended_opp() - Helper function to get proper OPP for the
1133 * freq value given to target callback.
1134 * @dev: The devfreq user device. (parent of devfreq)
1135 * @freq: The frequency given to target function
1136 * @flags: Flags handed from devfreq framework.
1137 *
1138 * Locking: This function must be called under rcu_read_lock(). opp is a rcu
1139 * protected pointer. The reason for the same is that the opp pointer which is
1140 * returned will remain valid for use with opp_get_{voltage, freq} only while
1141 * under the locked area. The pointer returned must be used prior to unlocking
1142 * with rcu_read_unlock() to maintain the integrity of the pointer.
1143 */
1144struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1145 unsigned long *freq,
1146 u32 flags)
1147{
1148 struct dev_pm_opp *opp;
1149
1150 if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1151 /* The freq is an upper bound. opp should be lower */
1152 opp = dev_pm_opp_find_freq_floor(dev, freq);
1153
1154 /* If not available, use the closest opp */
1155 if (opp == ERR_PTR(-ERANGE))
1156 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1157 } else {
1158 /* The freq is an lower bound. opp should be higher */
1159 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1160
1161 /* If not available, use the closest opp */
1162 if (opp == ERR_PTR(-ERANGE))
1163 opp = dev_pm_opp_find_freq_floor(dev, freq);
1164 }
1165
1166 return opp;
1167}
1168EXPORT_SYMBOL(devfreq_recommended_opp);
1169
1170/**
1171 * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1172 * for any changes in the OPP availability
1173 * changes
1174 * @dev: The devfreq user device. (parent of devfreq)
1175 * @devfreq: The devfreq object.
1176 */
1177int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1178{
1179 struct srcu_notifier_head *nh;
1180 int ret = 0;
1181
1182 rcu_read_lock();
1183 nh = dev_pm_opp_get_notifier(dev);
1184 if (IS_ERR(nh))
1185 ret = PTR_ERR(nh);
1186 rcu_read_unlock();
1187 if (!ret)
1188 ret = srcu_notifier_chain_register(nh, &devfreq->nb);
1189
1190 return ret;
1191}
1192EXPORT_SYMBOL(devfreq_register_opp_notifier);
1193
1194/**
1195 * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1196 * notified for any changes in the OPP
1197 * availability changes anymore.
1198 * @dev: The devfreq user device. (parent of devfreq)
1199 * @devfreq: The devfreq object.
1200 *
1201 * At exit() callback of devfreq_dev_profile, this must be included if
1202 * devfreq_recommended_opp is used.
1203 */
1204int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1205{
1206 struct srcu_notifier_head *nh;
1207 int ret = 0;
1208
1209 rcu_read_lock();
1210 nh = dev_pm_opp_get_notifier(dev);
1211 if (IS_ERR(nh))
1212 ret = PTR_ERR(nh);
1213 rcu_read_unlock();
1214 if (!ret)
1215 ret = srcu_notifier_chain_unregister(nh, &devfreq->nb);
1216
1217 return ret;
1218}
1219EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
1220
1221static void devm_devfreq_opp_release(struct device *dev, void *res)
1222{
1223 devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
1224}
1225
1226/**
1227 * devm_ devfreq_register_opp_notifier()
1228 * - Resource-managed devfreq_register_opp_notifier()
1229 * @dev: The devfreq user device. (parent of devfreq)
1230 * @devfreq: The devfreq object.
1231 */
1232int devm_devfreq_register_opp_notifier(struct device *dev,
1233 struct devfreq *devfreq)
1234{
1235 struct devfreq **ptr;
1236 int ret;
1237
1238 ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
1239 if (!ptr)
1240 return -ENOMEM;
1241
1242 ret = devfreq_register_opp_notifier(dev, devfreq);
1243 if (ret) {
1244 devres_free(ptr);
1245 return ret;
1246 }
1247
1248 *ptr = devfreq;
1249 devres_add(dev, ptr);
1250
1251 return 0;
1252}
1253EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
1254
1255/**
1256 * devm_devfreq_unregister_opp_notifier()
1257 * - Resource-managed devfreq_unregister_opp_notifier()
1258 * @dev: The devfreq user device. (parent of devfreq)
1259 * @devfreq: The devfreq object.
1260 */
1261void devm_devfreq_unregister_opp_notifier(struct device *dev,
1262 struct devfreq *devfreq)
1263{
1264 WARN_ON(devres_release(dev, devm_devfreq_opp_release,
1265 devm_devfreq_dev_match, devfreq));
1266}
1267EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
1268
1269MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
1270MODULE_DESCRIPTION("devfreq class support");
1271MODULE_LICENSE("GPL");