projects/linux·blob v4.2 · refs

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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 <[email protected]>
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 */
396static void _remove_devfreq(struct devfreq *devfreq)
397{
398 mutex_lock(&devfreq_list_lock);
399 if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) {
400 mutex_unlock(&devfreq_list_lock);
401 dev_warn(&devfreq->dev, "releasing devfreq which doesn't exist\n");
402 return;
403 }
404 list_del(&devfreq->node);
405 mutex_unlock(&devfreq_list_lock);
406
407 if (devfreq->governor)
408 devfreq->governor->event_handler(devfreq,
409 DEVFREQ_GOV_STOP, NULL);
410
411 if (devfreq->profile->exit)
412 devfreq->profile->exit(devfreq->dev.parent);
413
414 mutex_destroy(&devfreq->lock);
415 kfree(devfreq);
416}
417
418/**
419 * devfreq_dev_release() - Callback for struct device to release the device.
420 * @dev: the devfreq device
421 *
422 * This calls _remove_devfreq() if _remove_devfreq() is not called.
423 */
424static void devfreq_dev_release(struct device *dev)
425{
426 struct devfreq *devfreq = to_devfreq(dev);
427
428 _remove_devfreq(devfreq);
429}
430
431/**
432 * devfreq_add_device() - Add devfreq feature to the device
433 * @dev: the device to add devfreq feature.
434 * @profile: device-specific profile to run devfreq.
435 * @governor_name: name of the policy to choose frequency.
436 * @data: private data for the governor. The devfreq framework does not
437 * touch this value.
438 */
439struct devfreq *devfreq_add_device(struct device *dev,
440 struct devfreq_dev_profile *profile,
441 const char *governor_name,
442 void *data)
443{
444 struct devfreq *devfreq;
445 struct devfreq_governor *governor;
446 int err = 0;
447
448 if (!dev || !profile || !governor_name) {
449 dev_err(dev, "%s: Invalid parameters.\n", __func__);
450 return ERR_PTR(-EINVAL);
451 }
452
453 mutex_lock(&devfreq_list_lock);
454 devfreq = find_device_devfreq(dev);
455 mutex_unlock(&devfreq_list_lock);
456 if (!IS_ERR(devfreq)) {
457 dev_err(dev, "%s: Unable to create devfreq for the device. It already has one.\n", __func__);
458 err = -EINVAL;
459 goto err_out;
460 }
461
462 devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
463 if (!devfreq) {
464 dev_err(dev, "%s: Unable to create devfreq for the device\n",
465 __func__);
466 err = -ENOMEM;
467 goto err_out;
468 }
469
470 mutex_init(&devfreq->lock);
471 mutex_lock(&devfreq->lock);
472 devfreq->dev.parent = dev;
473 devfreq->dev.class = devfreq_class;
474 devfreq->dev.release = devfreq_dev_release;
475 devfreq->profile = profile;
476 strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
477 devfreq->previous_freq = profile->initial_freq;
478 devfreq->data = data;
479 devfreq->nb.notifier_call = devfreq_notifier_call;
480
481 devfreq->trans_table = devm_kzalloc(dev, sizeof(unsigned int) *
482 devfreq->profile->max_state *
483 devfreq->profile->max_state,
484 GFP_KERNEL);
485 devfreq->time_in_state = devm_kzalloc(dev, sizeof(unsigned int) *
486 devfreq->profile->max_state,
487 GFP_KERNEL);
488 devfreq->last_stat_updated = jiffies;
489
490 dev_set_name(&devfreq->dev, "%s", dev_name(dev));
491 err = device_register(&devfreq->dev);
492 if (err) {
493 put_device(&devfreq->dev);
494 mutex_unlock(&devfreq->lock);
495 goto err_dev;
496 }
497
498 mutex_unlock(&devfreq->lock);
499
500 mutex_lock(&devfreq_list_lock);
501 list_add(&devfreq->node, &devfreq_list);
502
503 governor = find_devfreq_governor(devfreq->governor_name);
504 if (!IS_ERR(governor))
505 devfreq->governor = governor;
506 if (devfreq->governor)
507 err = devfreq->governor->event_handler(devfreq,
508 DEVFREQ_GOV_START, NULL);
509 mutex_unlock(&devfreq_list_lock);
510 if (err) {
511 dev_err(dev, "%s: Unable to start governor for the device\n",
512 __func__);
513 goto err_init;
514 }
515
516 return devfreq;
517
518err_init:
519 list_del(&devfreq->node);
520 device_unregister(&devfreq->dev);
521err_dev:
522 kfree(devfreq);
523err_out:
524 return ERR_PTR(err);
525}
526EXPORT_SYMBOL(devfreq_add_device);
527
528/**
529 * devfreq_remove_device() - Remove devfreq feature from a device.
530 * @devfreq: the devfreq instance to be removed
531 *
532 * The opposite of devfreq_add_device().
533 */
534int devfreq_remove_device(struct devfreq *devfreq)
535{
536 if (!devfreq)
537 return -EINVAL;
538
539 device_unregister(&devfreq->dev);
540 put_device(&devfreq->dev);
541
542 return 0;
543}
544EXPORT_SYMBOL(devfreq_remove_device);
545
546static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
547{
548 struct devfreq **r = res;
549
550 if (WARN_ON(!r || !*r))
551 return 0;
552
553 return *r == data;
554}
555
556static void devm_devfreq_dev_release(struct device *dev, void *res)
557{
558 devfreq_remove_device(*(struct devfreq **)res);
559}
560
561/**
562 * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
563 * @dev: the device to add devfreq feature.
564 * @profile: device-specific profile to run devfreq.
565 * @governor_name: name of the policy to choose frequency.
566 * @data: private data for the governor. The devfreq framework does not
567 * touch this value.
568 *
569 * This function manages automatically the memory of devfreq device using device
570 * resource management and simplify the free operation for memory of devfreq
571 * device.
572 */
573struct devfreq *devm_devfreq_add_device(struct device *dev,
574 struct devfreq_dev_profile *profile,
575 const char *governor_name,
576 void *data)
577{
578 struct devfreq **ptr, *devfreq;
579
580 ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
581 if (!ptr)
582 return ERR_PTR(-ENOMEM);
583
584 devfreq = devfreq_add_device(dev, profile, governor_name, data);
585 if (IS_ERR(devfreq)) {
586 devres_free(ptr);
587 return ERR_PTR(-ENOMEM);
588 }
589
590 *ptr = devfreq;
591 devres_add(dev, ptr);
592
593 return devfreq;
594}
595EXPORT_SYMBOL(devm_devfreq_add_device);
596
597/**
598 * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
599 * @dev: the device to add devfreq feature.
600 * @devfreq: the devfreq instance to be removed
601 */
602void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
603{
604 WARN_ON(devres_release(dev, devm_devfreq_dev_release,
605 devm_devfreq_dev_match, devfreq));
606}
607EXPORT_SYMBOL(devm_devfreq_remove_device);
608
609/**
610 * devfreq_suspend_device() - Suspend devfreq of a device.
611 * @devfreq: the devfreq instance to be suspended
612 *
613 * This function is intended to be called by the pm callbacks
614 * (e.g., runtime_suspend, suspend) of the device driver that
615 * holds the devfreq.
616 */
617int devfreq_suspend_device(struct devfreq *devfreq)
618{
619 if (!devfreq)
620 return -EINVAL;
621
622 if (!devfreq->governor)
623 return 0;
624
625 return devfreq->governor->event_handler(devfreq,
626 DEVFREQ_GOV_SUSPEND, NULL);
627}
628EXPORT_SYMBOL(devfreq_suspend_device);
629
630/**
631 * devfreq_resume_device() - Resume devfreq of a device.
632 * @devfreq: the devfreq instance to be resumed
633 *
634 * This function is intended to be called by the pm callbacks
635 * (e.g., runtime_resume, resume) of the device driver that
636 * holds the devfreq.
637 */
638int devfreq_resume_device(struct devfreq *devfreq)
639{
640 if (!devfreq)
641 return -EINVAL;
642
643 if (!devfreq->governor)
644 return 0;
645
646 return devfreq->governor->event_handler(devfreq,
647 DEVFREQ_GOV_RESUME, NULL);
648}
649EXPORT_SYMBOL(devfreq_resume_device);
650
651/**
652 * devfreq_add_governor() - Add devfreq governor
653 * @governor: the devfreq governor to be added
654 */
655int devfreq_add_governor(struct devfreq_governor *governor)
656{
657 struct devfreq_governor *g;
658 struct devfreq *devfreq;
659 int err = 0;
660
661 if (!governor) {
662 pr_err("%s: Invalid parameters.\n", __func__);
663 return -EINVAL;
664 }
665
666 mutex_lock(&devfreq_list_lock);
667 g = find_devfreq_governor(governor->name);
668 if (!IS_ERR(g)) {
669 pr_err("%s: governor %s already registered\n", __func__,
670 g->name);
671 err = -EINVAL;
672 goto err_out;
673 }
674
675 list_add(&governor->node, &devfreq_governor_list);
676
677 list_for_each_entry(devfreq, &devfreq_list, node) {
678 int ret = 0;
679 struct device *dev = devfreq->dev.parent;
680
681 if (!strncmp(devfreq->governor_name, governor->name,
682 DEVFREQ_NAME_LEN)) {
683 /* The following should never occur */
684 if (devfreq->governor) {
685 dev_warn(dev,
686 "%s: Governor %s already present\n",
687 __func__, devfreq->governor->name);
688 ret = devfreq->governor->event_handler(devfreq,
689 DEVFREQ_GOV_STOP, NULL);
690 if (ret) {
691 dev_warn(dev,
692 "%s: Governor %s stop = %d\n",
693 __func__,
694 devfreq->governor->name, ret);
695 }
696 /* Fall through */
697 }
698 devfreq->governor = governor;
699 ret = devfreq->governor->event_handler(devfreq,
700 DEVFREQ_GOV_START, NULL);
701 if (ret) {
702 dev_warn(dev, "%s: Governor %s start=%d\n",
703 __func__, devfreq->governor->name,
704 ret);
705 }
706 }
707 }
708
709err_out:
710 mutex_unlock(&devfreq_list_lock);
711
712 return err;
713}
714EXPORT_SYMBOL(devfreq_add_governor);
715
716/**
717 * devfreq_remove_device() - Remove devfreq feature from a device.
718 * @governor: the devfreq governor to be removed
719 */
720int devfreq_remove_governor(struct devfreq_governor *governor)
721{
722 struct devfreq_governor *g;
723 struct devfreq *devfreq;
724 int err = 0;
725
726 if (!governor) {
727 pr_err("%s: Invalid parameters.\n", __func__);
728 return -EINVAL;
729 }
730
731 mutex_lock(&devfreq_list_lock);
732 g = find_devfreq_governor(governor->name);
733 if (IS_ERR(g)) {
734 pr_err("%s: governor %s not registered\n", __func__,
735 governor->name);
736 err = PTR_ERR(g);
737 goto err_out;
738 }
739 list_for_each_entry(devfreq, &devfreq_list, node) {
740 int ret;
741 struct device *dev = devfreq->dev.parent;
742
743 if (!strncmp(devfreq->governor_name, governor->name,
744 DEVFREQ_NAME_LEN)) {
745 /* we should have a devfreq governor! */
746 if (!devfreq->governor) {
747 dev_warn(dev, "%s: Governor %s NOT present\n",
748 __func__, governor->name);
749 continue;
750 /* Fall through */
751 }
752 ret = devfreq->governor->event_handler(devfreq,
753 DEVFREQ_GOV_STOP, NULL);
754 if (ret) {
755 dev_warn(dev, "%s: Governor %s stop=%d\n",
756 __func__, devfreq->governor->name,
757 ret);
758 }
759 devfreq->governor = NULL;
760 }
761 }
762
763 list_del(&governor->node);
764err_out:
765 mutex_unlock(&devfreq_list_lock);
766
767 return err;
768}
769EXPORT_SYMBOL(devfreq_remove_governor);
770
771static ssize_t governor_show(struct device *dev,
772 struct device_attribute *attr, char *buf)
773{
774 if (!to_devfreq(dev)->governor)
775 return -EINVAL;
776
777 return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name);
778}
779
780static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
781 const char *buf, size_t count)
782{
783 struct devfreq *df = to_devfreq(dev);
784 int ret;
785 char str_governor[DEVFREQ_NAME_LEN + 1];
786 struct devfreq_governor *governor;
787
788 ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
789 if (ret != 1)
790 return -EINVAL;
791
792 mutex_lock(&devfreq_list_lock);
793 governor = find_devfreq_governor(str_governor);
794 if (IS_ERR(governor)) {
795 ret = PTR_ERR(governor);
796 goto out;
797 }
798 if (df->governor == governor)
799 goto out;
800
801 if (df->governor) {
802 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
803 if (ret) {
804 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
805 __func__, df->governor->name, ret);
806 goto out;
807 }
808 }
809 df->governor = governor;
810 strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
811 ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
812 if (ret)
813 dev_warn(dev, "%s: Governor %s not started(%d)\n",
814 __func__, df->governor->name, ret);
815out:
816 mutex_unlock(&devfreq_list_lock);
817
818 if (!ret)
819 ret = count;
820 return ret;
821}
822static DEVICE_ATTR_RW(governor);
823
824static ssize_t available_governors_show(struct device *d,
825 struct device_attribute *attr,
826 char *buf)
827{
828 struct devfreq_governor *tmp_governor;
829 ssize_t count = 0;
830
831 mutex_lock(&devfreq_list_lock);
832 list_for_each_entry(tmp_governor, &devfreq_governor_list, node)
833 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
834 "%s ", tmp_governor->name);
835 mutex_unlock(&devfreq_list_lock);
836
837 /* Truncate the trailing space */
838 if (count)
839 count--;
840
841 count += sprintf(&buf[count], "\n");
842
843 return count;
844}
845static DEVICE_ATTR_RO(available_governors);
846
847static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
848 char *buf)
849{
850 unsigned long freq;
851 struct devfreq *devfreq = to_devfreq(dev);
852
853 if (devfreq->profile->get_cur_freq &&
854 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
855 return sprintf(buf, "%lu\n", freq);
856
857 return sprintf(buf, "%lu\n", devfreq->previous_freq);
858}
859static DEVICE_ATTR_RO(cur_freq);
860
861static ssize_t target_freq_show(struct device *dev,
862 struct device_attribute *attr, char *buf)
863{
864 return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
865}
866static DEVICE_ATTR_RO(target_freq);
867
868static ssize_t polling_interval_show(struct device *dev,
869 struct device_attribute *attr, char *buf)
870{
871 return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
872}
873
874static ssize_t polling_interval_store(struct device *dev,
875 struct device_attribute *attr,
876 const char *buf, size_t count)
877{
878 struct devfreq *df = to_devfreq(dev);
879 unsigned int value;
880 int ret;
881
882 if (!df->governor)
883 return -EINVAL;
884
885 ret = sscanf(buf, "%u", &value);
886 if (ret != 1)
887 return -EINVAL;
888
889 df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
890 ret = count;
891
892 return ret;
893}
894static DEVICE_ATTR_RW(polling_interval);
895
896static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
897 const char *buf, size_t count)
898{
899 struct devfreq *df = to_devfreq(dev);
900 unsigned long value;
901 int ret;
902 unsigned long max;
903
904 ret = sscanf(buf, "%lu", &value);
905 if (ret != 1)
906 return -EINVAL;
907
908 mutex_lock(&df->lock);
909 max = df->max_freq;
910 if (value && max && value > max) {
911 ret = -EINVAL;
912 goto unlock;
913 }
914
915 df->min_freq = value;
916 update_devfreq(df);
917 ret = count;
918unlock:
919 mutex_unlock(&df->lock);
920 return ret;
921}
922
923static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
924 char *buf)
925{
926 return sprintf(buf, "%lu\n", to_devfreq(dev)->min_freq);
927}
928
929static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
930 const char *buf, size_t count)
931{
932 struct devfreq *df = to_devfreq(dev);
933 unsigned long value;
934 int ret;
935 unsigned long min;
936
937 ret = sscanf(buf, "%lu", &value);
938 if (ret != 1)
939 return -EINVAL;
940
941 mutex_lock(&df->lock);
942 min = df->min_freq;
943 if (value && min && value < min) {
944 ret = -EINVAL;
945 goto unlock;
946 }
947
948 df->max_freq = value;
949 update_devfreq(df);
950 ret = count;
951unlock:
952 mutex_unlock(&df->lock);
953 return ret;
954}
955static DEVICE_ATTR_RW(min_freq);
956
957static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
958 char *buf)
959{
960 return sprintf(buf, "%lu\n", to_devfreq(dev)->max_freq);
961}
962static DEVICE_ATTR_RW(max_freq);
963
964static ssize_t available_frequencies_show(struct device *d,
965 struct device_attribute *attr,
966 char *buf)
967{
968 struct devfreq *df = to_devfreq(d);
969 struct device *dev = df->dev.parent;
970 struct dev_pm_opp *opp;
971 ssize_t count = 0;
972 unsigned long freq = 0;
973
974 rcu_read_lock();
975 do {
976 opp = dev_pm_opp_find_freq_ceil(dev, &freq);
977 if (IS_ERR(opp))
978 break;
979
980 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
981 "%lu ", freq);
982 freq++;
983 } while (1);
984 rcu_read_unlock();
985
986 /* Truncate the trailing space */
987 if (count)
988 count--;
989
990 count += sprintf(&buf[count], "\n");
991
992 return count;
993}
994static DEVICE_ATTR_RO(available_frequencies);
995
996static ssize_t trans_stat_show(struct device *dev,
997 struct device_attribute *attr, char *buf)
998{
999 struct devfreq *devfreq = to_devfreq(dev);
1000 ssize_t len;
1001 int i, j;
1002 unsigned int max_state = devfreq->profile->max_state;
1003
1004 if (!devfreq->stop_polling &&
1005 devfreq_update_status(devfreq, devfreq->previous_freq))
1006 return 0;
1007
1008 len = sprintf(buf, " From : To\n");
1009 len += sprintf(buf + len, " :");
1010 for (i = 0; i < max_state; i++)
1011 len += sprintf(buf + len, "%8u",
1012 devfreq->profile->freq_table[i]);
1013
1014 len += sprintf(buf + len, " time(ms)\n");
1015
1016 for (i = 0; i < max_state; i++) {
1017 if (devfreq->profile->freq_table[i]
1018 == devfreq->previous_freq) {
1019 len += sprintf(buf + len, "*");
1020 } else {
1021 len += sprintf(buf + len, " ");
1022 }
1023 len += sprintf(buf + len, "%8u:",
1024 devfreq->profile->freq_table[i]);
1025 for (j = 0; j < max_state; j++)
1026 len += sprintf(buf + len, "%8u",
1027 devfreq->trans_table[(i * max_state) + j]);
1028 len += sprintf(buf + len, "%10u\n",
1029 jiffies_to_msecs(devfreq->time_in_state[i]));
1030 }
1031
1032 len += sprintf(buf + len, "Total transition : %u\n",
1033 devfreq->total_trans);
1034 return len;
1035}
1036static DEVICE_ATTR_RO(trans_stat);
1037
1038static struct attribute *devfreq_attrs[] = {
1039 &dev_attr_governor.attr,
1040 &dev_attr_available_governors.attr,
1041 &dev_attr_cur_freq.attr,
1042 &dev_attr_available_frequencies.attr,
1043 &dev_attr_target_freq.attr,
1044 &dev_attr_polling_interval.attr,
1045 &dev_attr_min_freq.attr,
1046 &dev_attr_max_freq.attr,
1047 &dev_attr_trans_stat.attr,
1048 NULL,
1049};
1050ATTRIBUTE_GROUPS(devfreq);
1051
1052static int __init devfreq_init(void)
1053{
1054 devfreq_class = class_create(THIS_MODULE, "devfreq");
1055 if (IS_ERR(devfreq_class)) {
1056 pr_err("%s: couldn't create class\n", __FILE__);
1057 return PTR_ERR(devfreq_class);
1058 }
1059
1060 devfreq_wq = create_freezable_workqueue("devfreq_wq");
1061 if (!devfreq_wq) {
1062 class_destroy(devfreq_class);
1063 pr_err("%s: couldn't create workqueue\n", __FILE__);
1064 return -ENOMEM;
1065 }
1066 devfreq_class->dev_groups = devfreq_groups;
1067
1068 return 0;
1069}
1070subsys_initcall(devfreq_init);
1071
1072static void __exit devfreq_exit(void)
1073{
1074 class_destroy(devfreq_class);
1075 destroy_workqueue(devfreq_wq);
1076}
1077module_exit(devfreq_exit);
1078
1079/*
1080 * The followings are helper functions for devfreq user device drivers with
1081 * OPP framework.
1082 */
1083
1084/**
1085 * devfreq_recommended_opp() - Helper function to get proper OPP for the
1086 * freq value given to target callback.
1087 * @dev: The devfreq user device. (parent of devfreq)
1088 * @freq: The frequency given to target function
1089 * @flags: Flags handed from devfreq framework.
1090 *
1091 * Locking: This function must be called under rcu_read_lock(). opp is a rcu
1092 * protected pointer. The reason for the same is that the opp pointer which is
1093 * returned will remain valid for use with opp_get_{voltage, freq} only while
1094 * under the locked area. The pointer returned must be used prior to unlocking
1095 * with rcu_read_unlock() to maintain the integrity of the pointer.
1096 */
1097struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1098 unsigned long *freq,
1099 u32 flags)
1100{
1101 struct dev_pm_opp *opp;
1102
1103 if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1104 /* The freq is an upper bound. opp should be lower */
1105 opp = dev_pm_opp_find_freq_floor(dev, freq);
1106
1107 /* If not available, use the closest opp */
1108 if (opp == ERR_PTR(-ERANGE))
1109 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1110 } else {
1111 /* The freq is an lower bound. opp should be higher */
1112 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1113
1114 /* If not available, use the closest opp */
1115 if (opp == ERR_PTR(-ERANGE))
1116 opp = dev_pm_opp_find_freq_floor(dev, freq);
1117 }
1118
1119 return opp;
1120}
1121EXPORT_SYMBOL(devfreq_recommended_opp);
1122
1123/**
1124 * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1125 * for any changes in the OPP availability
1126 * changes
1127 * @dev: The devfreq user device. (parent of devfreq)
1128 * @devfreq: The devfreq object.
1129 */
1130int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1131{
1132 struct srcu_notifier_head *nh;
1133 int ret = 0;
1134
1135 rcu_read_lock();
1136 nh = dev_pm_opp_get_notifier(dev);
1137 if (IS_ERR(nh))
1138 ret = PTR_ERR(nh);
1139 rcu_read_unlock();
1140 if (!ret)
1141 ret = srcu_notifier_chain_register(nh, &devfreq->nb);
1142
1143 return ret;
1144}
1145EXPORT_SYMBOL(devfreq_register_opp_notifier);
1146
1147/**
1148 * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1149 * notified for any changes in the OPP
1150 * availability changes anymore.
1151 * @dev: The devfreq user device. (parent of devfreq)
1152 * @devfreq: The devfreq object.
1153 *
1154 * At exit() callback of devfreq_dev_profile, this must be included if
1155 * devfreq_recommended_opp is used.
1156 */
1157int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1158{
1159 struct srcu_notifier_head *nh;
1160 int ret = 0;
1161
1162 rcu_read_lock();
1163 nh = dev_pm_opp_get_notifier(dev);
1164 if (IS_ERR(nh))
1165 ret = PTR_ERR(nh);
1166 rcu_read_unlock();
1167 if (!ret)
1168 ret = srcu_notifier_chain_unregister(nh, &devfreq->nb);
1169
1170 return ret;
1171}
1172EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
1173
1174static void devm_devfreq_opp_release(struct device *dev, void *res)
1175{
1176 devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
1177}
1178
1179/**
1180 * devm_ devfreq_register_opp_notifier()
1181 * - Resource-managed devfreq_register_opp_notifier()
1182 * @dev: The devfreq user device. (parent of devfreq)
1183 * @devfreq: The devfreq object.
1184 */
1185int devm_devfreq_register_opp_notifier(struct device *dev,
1186 struct devfreq *devfreq)
1187{
1188 struct devfreq **ptr;
1189 int ret;
1190
1191 ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
1192 if (!ptr)
1193 return -ENOMEM;
1194
1195 ret = devfreq_register_opp_notifier(dev, devfreq);
1196 if (ret) {
1197 devres_free(ptr);
1198 return ret;
1199 }
1200
1201 *ptr = devfreq;
1202 devres_add(dev, ptr);
1203
1204 return 0;
1205}
1206EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
1207
1208/**
1209 * devm_devfreq_unregister_opp_notifier()
1210 * - Resource-managed devfreq_unregister_opp_notifier()
1211 * @dev: The devfreq user device. (parent of devfreq)
1212 * @devfreq: The devfreq object.
1213 */
1214void devm_devfreq_unregister_opp_notifier(struct device *dev,
1215 struct devfreq *devfreq)
1216{
1217 WARN_ON(devres_release(dev, devm_devfreq_opp_release,
1218 devm_devfreq_dev_match, devfreq));
1219}
1220EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
1221
1222MODULE_AUTHOR("MyungJoo Ham <[email protected]>");
1223MODULE_DESCRIPTION("devfreq class support");
1224MODULE_LICENSE("GPL");