projects/linux·blob v5.4 · refs

1709 lines · 42.5 KiB

1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
4 * for Non-CPU Devices.
5 *
6 * Copyright (C) 2011 Samsung Electronics
7 * MyungJoo Ham <[email protected]>
8 */
9
10#include <linux/kernel.h>
11#include <linux/kmod.h>
12#include <linux/sched.h>
13#include <linux/errno.h>
14#include <linux/err.h>
15#include <linux/init.h>
16#include <linux/export.h>
17#include <linux/slab.h>
18#include <linux/stat.h>
19#include <linux/pm_opp.h>
20#include <linux/devfreq.h>
21#include <linux/workqueue.h>
22#include <linux/platform_device.h>
23#include <linux/list.h>
24#include <linux/printk.h>
25#include <linux/hrtimer.h>
26#include <linux/of.h>
27#include "governor.h"
28
29#define CREATE_TRACE_POINTS
30#include <trace/events/devfreq.h>
31
32static struct class *devfreq_class;
33
34/*
35 * devfreq core provides delayed work based load monitoring helper
36 * functions. Governors can use these or can implement their own
37 * monitoring mechanism.
38 */
39static struct workqueue_struct *devfreq_wq;
40
41/* The list of all device-devfreq governors */
42static LIST_HEAD(devfreq_governor_list);
43/* The list of all device-devfreq */
44static LIST_HEAD(devfreq_list);
45static DEFINE_MUTEX(devfreq_list_lock);
46
47/**
48 * find_device_devfreq() - find devfreq struct using device pointer
49 * @dev: device pointer used to lookup device devfreq.
50 *
51 * Search the list of device devfreqs and return the matched device's
52 * devfreq info. devfreq_list_lock should be held by the caller.
53 */
54static struct devfreq *find_device_devfreq(struct device *dev)
55{
56 struct devfreq *tmp_devfreq;
57
58 if (IS_ERR_OR_NULL(dev)) {
59 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
60 return ERR_PTR(-EINVAL);
61 }
62 WARN(!mutex_is_locked(&devfreq_list_lock),
63 "devfreq_list_lock must be locked.");
64
65 list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
66 if (tmp_devfreq->dev.parent == dev)
67 return tmp_devfreq;
68 }
69
70 return ERR_PTR(-ENODEV);
71}
72
73static unsigned long find_available_min_freq(struct devfreq *devfreq)
74{
75 struct dev_pm_opp *opp;
76 unsigned long min_freq = 0;
77
78 opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &min_freq);
79 if (IS_ERR(opp))
80 min_freq = 0;
81 else
82 dev_pm_opp_put(opp);
83
84 return min_freq;
85}
86
87static unsigned long find_available_max_freq(struct devfreq *devfreq)
88{
89 struct dev_pm_opp *opp;
90 unsigned long max_freq = ULONG_MAX;
91
92 opp = dev_pm_opp_find_freq_floor(devfreq->dev.parent, &max_freq);
93 if (IS_ERR(opp))
94 max_freq = 0;
95 else
96 dev_pm_opp_put(opp);
97
98 return max_freq;
99}
100
101/**
102 * devfreq_get_freq_level() - Lookup freq_table for the frequency
103 * @devfreq: the devfreq instance
104 * @freq: the target frequency
105 */
106static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
107{
108 int lev;
109
110 for (lev = 0; lev < devfreq->profile->max_state; lev++)
111 if (freq == devfreq->profile->freq_table[lev])
112 return lev;
113
114 return -EINVAL;
115}
116
117static int set_freq_table(struct devfreq *devfreq)
118{
119 struct devfreq_dev_profile *profile = devfreq->profile;
120 struct dev_pm_opp *opp;
121 unsigned long freq;
122 int i, count;
123
124 /* Initialize the freq_table from OPP table */
125 count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
126 if (count <= 0)
127 return -EINVAL;
128
129 profile->max_state = count;
130 profile->freq_table = devm_kcalloc(devfreq->dev.parent,
131 profile->max_state,
132 sizeof(*profile->freq_table),
133 GFP_KERNEL);
134 if (!profile->freq_table) {
135 profile->max_state = 0;
136 return -ENOMEM;
137 }
138
139 for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
140 opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
141 if (IS_ERR(opp)) {
142 devm_kfree(devfreq->dev.parent, profile->freq_table);
143 profile->max_state = 0;
144 return PTR_ERR(opp);
145 }
146 dev_pm_opp_put(opp);
147 profile->freq_table[i] = freq;
148 }
149
150 return 0;
151}
152
153/**
154 * devfreq_update_status() - Update statistics of devfreq behavior
155 * @devfreq: the devfreq instance
156 * @freq: the update target frequency
157 */
158int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
159{
160 int lev, prev_lev, ret = 0;
161 unsigned long cur_time;
162
163 cur_time = jiffies;
164
165 /* Immediately exit if previous_freq is not initialized yet. */
166 if (!devfreq->previous_freq)
167 goto out;
168
169 prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
170 if (prev_lev < 0) {
171 ret = prev_lev;
172 goto out;
173 }
174
175 devfreq->time_in_state[prev_lev] +=
176 cur_time - devfreq->last_stat_updated;
177
178 lev = devfreq_get_freq_level(devfreq, freq);
179 if (lev < 0) {
180 ret = lev;
181 goto out;
182 }
183
184 if (lev != prev_lev) {
185 devfreq->trans_table[(prev_lev *
186 devfreq->profile->max_state) + lev]++;
187 devfreq->total_trans++;
188 }
189
190out:
191 devfreq->last_stat_updated = cur_time;
192 return ret;
193}
194EXPORT_SYMBOL(devfreq_update_status);
195
196/**
197 * find_devfreq_governor() - find devfreq governor from name
198 * @name: name of the governor
199 *
200 * Search the list of devfreq governors and return the matched
201 * governor's pointer. devfreq_list_lock should be held by the caller.
202 */
203static struct devfreq_governor *find_devfreq_governor(const char *name)
204{
205 struct devfreq_governor *tmp_governor;
206
207 if (IS_ERR_OR_NULL(name)) {
208 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
209 return ERR_PTR(-EINVAL);
210 }
211 WARN(!mutex_is_locked(&devfreq_list_lock),
212 "devfreq_list_lock must be locked.");
213
214 list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
215 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
216 return tmp_governor;
217 }
218
219 return ERR_PTR(-ENODEV);
220}
221
222/**
223 * try_then_request_governor() - Try to find the governor and request the
224 * module if is not found.
225 * @name: name of the governor
226 *
227 * Search the list of devfreq governors and request the module and try again
228 * if is not found. This can happen when both drivers (the governor driver
229 * and the driver that call devfreq_add_device) are built as modules.
230 * devfreq_list_lock should be held by the caller. Returns the matched
231 * governor's pointer or an error pointer.
232 */
233static struct devfreq_governor *try_then_request_governor(const char *name)
234{
235 struct devfreq_governor *governor;
236 int err = 0;
237
238 if (IS_ERR_OR_NULL(name)) {
239 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
240 return ERR_PTR(-EINVAL);
241 }
242 WARN(!mutex_is_locked(&devfreq_list_lock),
243 "devfreq_list_lock must be locked.");
244
245 governor = find_devfreq_governor(name);
246 if (IS_ERR(governor)) {
247 mutex_unlock(&devfreq_list_lock);
248
249 if (!strncmp(name, DEVFREQ_GOV_SIMPLE_ONDEMAND,
250 DEVFREQ_NAME_LEN))
251 err = request_module("governor_%s", "simpleondemand");
252 else
253 err = request_module("governor_%s", name);
254 /* Restore previous state before return */
255 mutex_lock(&devfreq_list_lock);
256 if (err)
257 return (err < 0) ? ERR_PTR(err) : ERR_PTR(-EINVAL);
258
259 governor = find_devfreq_governor(name);
260 }
261
262 return governor;
263}
264
265static int devfreq_notify_transition(struct devfreq *devfreq,
266 struct devfreq_freqs *freqs, unsigned int state)
267{
268 if (!devfreq)
269 return -EINVAL;
270
271 switch (state) {
272 case DEVFREQ_PRECHANGE:
273 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
274 DEVFREQ_PRECHANGE, freqs);
275 break;
276
277 case DEVFREQ_POSTCHANGE:
278 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
279 DEVFREQ_POSTCHANGE, freqs);
280 break;
281 default:
282 return -EINVAL;
283 }
284
285 return 0;
286}
287
288static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq,
289 u32 flags)
290{
291 struct devfreq_freqs freqs;
292 unsigned long cur_freq;
293 int err = 0;
294
295 if (devfreq->profile->get_cur_freq)
296 devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
297 else
298 cur_freq = devfreq->previous_freq;
299
300 freqs.old = cur_freq;
301 freqs.new = new_freq;
302 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
303
304 err = devfreq->profile->target(devfreq->dev.parent, &new_freq, flags);
305 if (err) {
306 freqs.new = cur_freq;
307 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
308 return err;
309 }
310
311 freqs.new = new_freq;
312 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
313
314 if (devfreq_update_status(devfreq, new_freq))
315 dev_err(&devfreq->dev,
316 "Couldn't update frequency transition information.\n");
317
318 devfreq->previous_freq = new_freq;
319
320 if (devfreq->suspend_freq)
321 devfreq->resume_freq = cur_freq;
322
323 return err;
324}
325
326/* Load monitoring helper functions for governors use */
327
328/**
329 * update_devfreq() - Reevaluate the device and configure frequency.
330 * @devfreq: the devfreq instance.
331 *
332 * Note: Lock devfreq->lock before calling update_devfreq
333 * This function is exported for governors.
334 */
335int update_devfreq(struct devfreq *devfreq)
336{
337 unsigned long freq, min_freq, max_freq;
338 int err = 0;
339 u32 flags = 0;
340
341 if (!mutex_is_locked(&devfreq->lock)) {
342 WARN(true, "devfreq->lock must be locked by the caller.\n");
343 return -EINVAL;
344 }
345
346 if (!devfreq->governor)
347 return -EINVAL;
348
349 /* Reevaluate the proper frequency */
350 err = devfreq->governor->get_target_freq(devfreq, &freq);
351 if (err)
352 return err;
353
354 /*
355 * Adjust the frequency with user freq, QoS and available freq.
356 *
357 * List from the highest priority
358 * max_freq
359 * min_freq
360 */
361 max_freq = min(devfreq->scaling_max_freq, devfreq->max_freq);
362 min_freq = max(devfreq->scaling_min_freq, devfreq->min_freq);
363
364 if (freq < min_freq) {
365 freq = min_freq;
366 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
367 }
368 if (freq > max_freq) {
369 freq = max_freq;
370 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
371 }
372
373 return devfreq_set_target(devfreq, freq, flags);
374
375}
376EXPORT_SYMBOL(update_devfreq);
377
378/**
379 * devfreq_monitor() - Periodically poll devfreq objects.
380 * @work: the work struct used to run devfreq_monitor periodically.
381 *
382 */
383static void devfreq_monitor(struct work_struct *work)
384{
385 int err;
386 struct devfreq *devfreq = container_of(work,
387 struct devfreq, work.work);
388
389 mutex_lock(&devfreq->lock);
390 err = update_devfreq(devfreq);
391 if (err)
392 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
393
394 queue_delayed_work(devfreq_wq, &devfreq->work,
395 msecs_to_jiffies(devfreq->profile->polling_ms));
396 mutex_unlock(&devfreq->lock);
397
398 trace_devfreq_monitor(devfreq);
399}
400
401/**
402 * devfreq_monitor_start() - Start load monitoring of devfreq instance
403 * @devfreq: the devfreq instance.
404 *
405 * Helper function for starting devfreq device load monitoring. By
406 * default delayed work based monitoring is supported. Function
407 * to be called from governor in response to DEVFREQ_GOV_START
408 * event when device is added to devfreq framework.
409 */
410void devfreq_monitor_start(struct devfreq *devfreq)
411{
412 INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
413 if (devfreq->profile->polling_ms)
414 queue_delayed_work(devfreq_wq, &devfreq->work,
415 msecs_to_jiffies(devfreq->profile->polling_ms));
416}
417EXPORT_SYMBOL(devfreq_monitor_start);
418
419/**
420 * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
421 * @devfreq: the devfreq instance.
422 *
423 * Helper function to stop devfreq device load monitoring. Function
424 * to be called from governor in response to DEVFREQ_GOV_STOP
425 * event when device is removed from devfreq framework.
426 */
427void devfreq_monitor_stop(struct devfreq *devfreq)
428{
429 cancel_delayed_work_sync(&devfreq->work);
430}
431EXPORT_SYMBOL(devfreq_monitor_stop);
432
433/**
434 * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
435 * @devfreq: the devfreq instance.
436 *
437 * Helper function to suspend devfreq device load monitoring. Function
438 * to be called from governor in response to DEVFREQ_GOV_SUSPEND
439 * event or when polling interval is set to zero.
440 *
441 * Note: Though this function is same as devfreq_monitor_stop(),
442 * intentionally kept separate to provide hooks for collecting
443 * transition statistics.
444 */
445void devfreq_monitor_suspend(struct devfreq *devfreq)
446{
447 mutex_lock(&devfreq->lock);
448 if (devfreq->stop_polling) {
449 mutex_unlock(&devfreq->lock);
450 return;
451 }
452
453 devfreq_update_status(devfreq, devfreq->previous_freq);
454 devfreq->stop_polling = true;
455 mutex_unlock(&devfreq->lock);
456 cancel_delayed_work_sync(&devfreq->work);
457}
458EXPORT_SYMBOL(devfreq_monitor_suspend);
459
460/**
461 * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
462 * @devfreq: the devfreq instance.
463 *
464 * Helper function to resume devfreq device load monitoring. Function
465 * to be called from governor in response to DEVFREQ_GOV_RESUME
466 * event or when polling interval is set to non-zero.
467 */
468void devfreq_monitor_resume(struct devfreq *devfreq)
469{
470 unsigned long freq;
471
472 mutex_lock(&devfreq->lock);
473 if (!devfreq->stop_polling)
474 goto out;
475
476 if (!delayed_work_pending(&devfreq->work) &&
477 devfreq->profile->polling_ms)
478 queue_delayed_work(devfreq_wq, &devfreq->work,
479 msecs_to_jiffies(devfreq->profile->polling_ms));
480
481 devfreq->last_stat_updated = jiffies;
482 devfreq->stop_polling = false;
483
484 if (devfreq->profile->get_cur_freq &&
485 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
486 devfreq->previous_freq = freq;
487
488out:
489 mutex_unlock(&devfreq->lock);
490}
491EXPORT_SYMBOL(devfreq_monitor_resume);
492
493/**
494 * devfreq_interval_update() - Update device devfreq monitoring interval
495 * @devfreq: the devfreq instance.
496 * @delay: new polling interval to be set.
497 *
498 * Helper function to set new load monitoring polling interval. Function
499 * to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
500 */
501void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
502{
503 unsigned int cur_delay = devfreq->profile->polling_ms;
504 unsigned int new_delay = *delay;
505
506 mutex_lock(&devfreq->lock);
507 devfreq->profile->polling_ms = new_delay;
508
509 if (devfreq->stop_polling)
510 goto out;
511
512 /* if new delay is zero, stop polling */
513 if (!new_delay) {
514 mutex_unlock(&devfreq->lock);
515 cancel_delayed_work_sync(&devfreq->work);
516 return;
517 }
518
519 /* if current delay is zero, start polling with new delay */
520 if (!cur_delay) {
521 queue_delayed_work(devfreq_wq, &devfreq->work,
522 msecs_to_jiffies(devfreq->profile->polling_ms));
523 goto out;
524 }
525
526 /* if current delay is greater than new delay, restart polling */
527 if (cur_delay > new_delay) {
528 mutex_unlock(&devfreq->lock);
529 cancel_delayed_work_sync(&devfreq->work);
530 mutex_lock(&devfreq->lock);
531 if (!devfreq->stop_polling)
532 queue_delayed_work(devfreq_wq, &devfreq->work,
533 msecs_to_jiffies(devfreq->profile->polling_ms));
534 }
535out:
536 mutex_unlock(&devfreq->lock);
537}
538EXPORT_SYMBOL(devfreq_interval_update);
539
540/**
541 * devfreq_notifier_call() - Notify that the device frequency requirements
542 * has been changed out of devfreq framework.
543 * @nb: the notifier_block (supposed to be devfreq->nb)
544 * @type: not used
545 * @devp: not used
546 *
547 * Called by a notifier that uses devfreq->nb.
548 */
549static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
550 void *devp)
551{
552 struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
553 int ret;
554
555 mutex_lock(&devfreq->lock);
556
557 devfreq->scaling_min_freq = find_available_min_freq(devfreq);
558 if (!devfreq->scaling_min_freq) {
559 mutex_unlock(&devfreq->lock);
560 return -EINVAL;
561 }
562
563 devfreq->scaling_max_freq = find_available_max_freq(devfreq);
564 if (!devfreq->scaling_max_freq) {
565 mutex_unlock(&devfreq->lock);
566 return -EINVAL;
567 }
568
569 ret = update_devfreq(devfreq);
570 mutex_unlock(&devfreq->lock);
571
572 return ret;
573}
574
575/**
576 * devfreq_dev_release() - Callback for struct device to release the device.
577 * @dev: the devfreq device
578 *
579 * Remove devfreq from the list and release its resources.
580 */
581static void devfreq_dev_release(struct device *dev)
582{
583 struct devfreq *devfreq = to_devfreq(dev);
584
585 mutex_lock(&devfreq_list_lock);
586 if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) {
587 mutex_unlock(&devfreq_list_lock);
588 dev_warn(&devfreq->dev, "releasing devfreq which doesn't exist\n");
589 return;
590 }
591 list_del(&devfreq->node);
592 mutex_unlock(&devfreq_list_lock);
593
594 if (devfreq->profile->exit)
595 devfreq->profile->exit(devfreq->dev.parent);
596
597 mutex_destroy(&devfreq->lock);
598 kfree(devfreq);
599}
600
601/**
602 * devfreq_add_device() - Add devfreq feature to the device
603 * @dev: the device to add devfreq feature.
604 * @profile: device-specific profile to run devfreq.
605 * @governor_name: name of the policy to choose frequency.
606 * @data: private data for the governor. The devfreq framework does not
607 * touch this value.
608 */
609struct devfreq *devfreq_add_device(struct device *dev,
610 struct devfreq_dev_profile *profile,
611 const char *governor_name,
612 void *data)
613{
614 struct devfreq *devfreq;
615 struct devfreq_governor *governor;
616 static atomic_t devfreq_no = ATOMIC_INIT(-1);
617 int err = 0;
618
619 if (!dev || !profile || !governor_name) {
620 dev_err(dev, "%s: Invalid parameters.\n", __func__);
621 return ERR_PTR(-EINVAL);
622 }
623
624 mutex_lock(&devfreq_list_lock);
625 devfreq = find_device_devfreq(dev);
626 mutex_unlock(&devfreq_list_lock);
627 if (!IS_ERR(devfreq)) {
628 dev_err(dev, "%s: Unable to create devfreq for the device.\n",
629 __func__);
630 err = -EINVAL;
631 goto err_out;
632 }
633
634 devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
635 if (!devfreq) {
636 err = -ENOMEM;
637 goto err_out;
638 }
639
640 mutex_init(&devfreq->lock);
641 mutex_lock(&devfreq->lock);
642 devfreq->dev.parent = dev;
643 devfreq->dev.class = devfreq_class;
644 devfreq->dev.release = devfreq_dev_release;
645 devfreq->profile = profile;
646 strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
647 devfreq->previous_freq = profile->initial_freq;
648 devfreq->last_status.current_frequency = profile->initial_freq;
649 devfreq->data = data;
650 devfreq->nb.notifier_call = devfreq_notifier_call;
651
652 if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
653 mutex_unlock(&devfreq->lock);
654 err = set_freq_table(devfreq);
655 if (err < 0)
656 goto err_dev;
657 mutex_lock(&devfreq->lock);
658 }
659
660 devfreq->scaling_min_freq = find_available_min_freq(devfreq);
661 if (!devfreq->scaling_min_freq) {
662 mutex_unlock(&devfreq->lock);
663 err = -EINVAL;
664 goto err_dev;
665 }
666 devfreq->min_freq = devfreq->scaling_min_freq;
667
668 devfreq->scaling_max_freq = find_available_max_freq(devfreq);
669 if (!devfreq->scaling_max_freq) {
670 mutex_unlock(&devfreq->lock);
671 err = -EINVAL;
672 goto err_dev;
673 }
674 devfreq->max_freq = devfreq->scaling_max_freq;
675
676 devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);
677 atomic_set(&devfreq->suspend_count, 0);
678
679 dev_set_name(&devfreq->dev, "devfreq%d",
680 atomic_inc_return(&devfreq_no));
681 err = device_register(&devfreq->dev);
682 if (err) {
683 mutex_unlock(&devfreq->lock);
684 put_device(&devfreq->dev);
685 goto err_out;
686 }
687
688 devfreq->trans_table = devm_kzalloc(&devfreq->dev,
689 array3_size(sizeof(unsigned int),
690 devfreq->profile->max_state,
691 devfreq->profile->max_state),
692 GFP_KERNEL);
693 if (!devfreq->trans_table) {
694 mutex_unlock(&devfreq->lock);
695 err = -ENOMEM;
696 goto err_devfreq;
697 }
698
699 devfreq->time_in_state = devm_kcalloc(&devfreq->dev,
700 devfreq->profile->max_state,
701 sizeof(unsigned long),
702 GFP_KERNEL);
703 if (!devfreq->time_in_state) {
704 mutex_unlock(&devfreq->lock);
705 err = -ENOMEM;
706 goto err_devfreq;
707 }
708
709 devfreq->last_stat_updated = jiffies;
710
711 srcu_init_notifier_head(&devfreq->transition_notifier_list);
712
713 mutex_unlock(&devfreq->lock);
714
715 mutex_lock(&devfreq_list_lock);
716
717 governor = try_then_request_governor(devfreq->governor_name);
718 if (IS_ERR(governor)) {
719 dev_err(dev, "%s: Unable to find governor for the device\n",
720 __func__);
721 err = PTR_ERR(governor);
722 goto err_init;
723 }
724
725 devfreq->governor = governor;
726 err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
727 NULL);
728 if (err) {
729 dev_err(dev, "%s: Unable to start governor for the device\n",
730 __func__);
731 goto err_init;
732 }
733
734 list_add(&devfreq->node, &devfreq_list);
735
736 mutex_unlock(&devfreq_list_lock);
737
738 return devfreq;
739
740err_init:
741 mutex_unlock(&devfreq_list_lock);
742err_devfreq:
743 devfreq_remove_device(devfreq);
744 devfreq = NULL;
745err_dev:
746 kfree(devfreq);
747err_out:
748 return ERR_PTR(err);
749}
750EXPORT_SYMBOL(devfreq_add_device);
751
752/**
753 * devfreq_remove_device() - Remove devfreq feature from a device.
754 * @devfreq: the devfreq instance to be removed
755 *
756 * The opposite of devfreq_add_device().
757 */
758int devfreq_remove_device(struct devfreq *devfreq)
759{
760 if (!devfreq)
761 return -EINVAL;
762
763 if (devfreq->governor)
764 devfreq->governor->event_handler(devfreq,
765 DEVFREQ_GOV_STOP, NULL);
766 device_unregister(&devfreq->dev);
767
768 return 0;
769}
770EXPORT_SYMBOL(devfreq_remove_device);
771
772static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
773{
774 struct devfreq **r = res;
775
776 if (WARN_ON(!r || !*r))
777 return 0;
778
779 return *r == data;
780}
781
782static void devm_devfreq_dev_release(struct device *dev, void *res)
783{
784 devfreq_remove_device(*(struct devfreq **)res);
785}
786
787/**
788 * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
789 * @dev: the device to add devfreq feature.
790 * @profile: device-specific profile to run devfreq.
791 * @governor_name: name of the policy to choose frequency.
792 * @data: private data for the governor. The devfreq framework does not
793 * touch this value.
794 *
795 * This function manages automatically the memory of devfreq device using device
796 * resource management and simplify the free operation for memory of devfreq
797 * device.
798 */
799struct devfreq *devm_devfreq_add_device(struct device *dev,
800 struct devfreq_dev_profile *profile,
801 const char *governor_name,
802 void *data)
803{
804 struct devfreq **ptr, *devfreq;
805
806 ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
807 if (!ptr)
808 return ERR_PTR(-ENOMEM);
809
810 devfreq = devfreq_add_device(dev, profile, governor_name, data);
811 if (IS_ERR(devfreq)) {
812 devres_free(ptr);
813 return devfreq;
814 }
815
816 *ptr = devfreq;
817 devres_add(dev, ptr);
818
819 return devfreq;
820}
821EXPORT_SYMBOL(devm_devfreq_add_device);
822
823#ifdef CONFIG_OF
824/*
825 * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
826 * @dev - instance to the given device
827 * @index - index into list of devfreq
828 *
829 * return the instance of devfreq device
830 */
831struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
832{
833 struct device_node *node;
834 struct devfreq *devfreq;
835
836 if (!dev)
837 return ERR_PTR(-EINVAL);
838
839 if (!dev->of_node)
840 return ERR_PTR(-EINVAL);
841
842 node = of_parse_phandle(dev->of_node, "devfreq", index);
843 if (!node)
844 return ERR_PTR(-ENODEV);
845
846 mutex_lock(&devfreq_list_lock);
847 list_for_each_entry(devfreq, &devfreq_list, node) {
848 if (devfreq->dev.parent
849 && devfreq->dev.parent->of_node == node) {
850 mutex_unlock(&devfreq_list_lock);
851 of_node_put(node);
852 return devfreq;
853 }
854 }
855 mutex_unlock(&devfreq_list_lock);
856 of_node_put(node);
857
858 return ERR_PTR(-EPROBE_DEFER);
859}
860#else
861struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
862{
863 return ERR_PTR(-ENODEV);
864}
865#endif /* CONFIG_OF */
866EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
867
868/**
869 * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
870 * @dev: the device from which to remove devfreq feature.
871 * @devfreq: the devfreq instance to be removed
872 */
873void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
874{
875 WARN_ON(devres_release(dev, devm_devfreq_dev_release,
876 devm_devfreq_dev_match, devfreq));
877}
878EXPORT_SYMBOL(devm_devfreq_remove_device);
879
880/**
881 * devfreq_suspend_device() - Suspend devfreq of a device.
882 * @devfreq: the devfreq instance to be suspended
883 *
884 * This function is intended to be called by the pm callbacks
885 * (e.g., runtime_suspend, suspend) of the device driver that
886 * holds the devfreq.
887 */
888int devfreq_suspend_device(struct devfreq *devfreq)
889{
890 int ret;
891
892 if (!devfreq)
893 return -EINVAL;
894
895 if (atomic_inc_return(&devfreq->suspend_count) > 1)
896 return 0;
897
898 if (devfreq->governor) {
899 ret = devfreq->governor->event_handler(devfreq,
900 DEVFREQ_GOV_SUSPEND, NULL);
901 if (ret)
902 return ret;
903 }
904
905 if (devfreq->suspend_freq) {
906 ret = devfreq_set_target(devfreq, devfreq->suspend_freq, 0);
907 if (ret)
908 return ret;
909 }
910
911 return 0;
912}
913EXPORT_SYMBOL(devfreq_suspend_device);
914
915/**
916 * devfreq_resume_device() - Resume devfreq of a device.
917 * @devfreq: the devfreq instance to be resumed
918 *
919 * This function is intended to be called by the pm callbacks
920 * (e.g., runtime_resume, resume) of the device driver that
921 * holds the devfreq.
922 */
923int devfreq_resume_device(struct devfreq *devfreq)
924{
925 int ret;
926
927 if (!devfreq)
928 return -EINVAL;
929
930 if (atomic_dec_return(&devfreq->suspend_count) >= 1)
931 return 0;
932
933 if (devfreq->resume_freq) {
934 ret = devfreq_set_target(devfreq, devfreq->resume_freq, 0);
935 if (ret)
936 return ret;
937 }
938
939 if (devfreq->governor) {
940 ret = devfreq->governor->event_handler(devfreq,
941 DEVFREQ_GOV_RESUME, NULL);
942 if (ret)
943 return ret;
944 }
945
946 return 0;
947}
948EXPORT_SYMBOL(devfreq_resume_device);
949
950/**
951 * devfreq_suspend() - Suspend devfreq governors and devices
952 *
953 * Called during system wide Suspend/Hibernate cycles for suspending governors
954 * and devices preserving the state for resume. On some platforms the devfreq
955 * device must have precise state (frequency) after resume in order to provide
956 * fully operating setup.
957 */
958void devfreq_suspend(void)
959{
960 struct devfreq *devfreq;
961 int ret;
962
963 mutex_lock(&devfreq_list_lock);
964 list_for_each_entry(devfreq, &devfreq_list, node) {
965 ret = devfreq_suspend_device(devfreq);
966 if (ret)
967 dev_err(&devfreq->dev,
968 "failed to suspend devfreq device\n");
969 }
970 mutex_unlock(&devfreq_list_lock);
971}
972
973/**
974 * devfreq_resume() - Resume devfreq governors and devices
975 *
976 * Called during system wide Suspend/Hibernate cycle for resuming governors and
977 * devices that are suspended with devfreq_suspend().
978 */
979void devfreq_resume(void)
980{
981 struct devfreq *devfreq;
982 int ret;
983
984 mutex_lock(&devfreq_list_lock);
985 list_for_each_entry(devfreq, &devfreq_list, node) {
986 ret = devfreq_resume_device(devfreq);
987 if (ret)
988 dev_warn(&devfreq->dev,
989 "failed to resume devfreq device\n");
990 }
991 mutex_unlock(&devfreq_list_lock);
992}
993
994/**
995 * devfreq_add_governor() - Add devfreq governor
996 * @governor: the devfreq governor to be added
997 */
998int devfreq_add_governor(struct devfreq_governor *governor)
999{
1000 struct devfreq_governor *g;
1001 struct devfreq *devfreq;
1002 int err = 0;
1003
1004 if (!governor) {
1005 pr_err("%s: Invalid parameters.\n", __func__);
1006 return -EINVAL;
1007 }
1008
1009 mutex_lock(&devfreq_list_lock);
1010 g = find_devfreq_governor(governor->name);
1011 if (!IS_ERR(g)) {
1012 pr_err("%s: governor %s already registered\n", __func__,
1013 g->name);
1014 err = -EINVAL;
1015 goto err_out;
1016 }
1017
1018 list_add(&governor->node, &devfreq_governor_list);
1019
1020 list_for_each_entry(devfreq, &devfreq_list, node) {
1021 int ret = 0;
1022 struct device *dev = devfreq->dev.parent;
1023
1024 if (!strncmp(devfreq->governor_name, governor->name,
1025 DEVFREQ_NAME_LEN)) {
1026 /* The following should never occur */
1027 if (devfreq->governor) {
1028 dev_warn(dev,
1029 "%s: Governor %s already present\n",
1030 __func__, devfreq->governor->name);
1031 ret = devfreq->governor->event_handler(devfreq,
1032 DEVFREQ_GOV_STOP, NULL);
1033 if (ret) {
1034 dev_warn(dev,
1035 "%s: Governor %s stop = %d\n",
1036 __func__,
1037 devfreq->governor->name, ret);
1038 }
1039 /* Fall through */
1040 }
1041 devfreq->governor = governor;
1042 ret = devfreq->governor->event_handler(devfreq,
1043 DEVFREQ_GOV_START, NULL);
1044 if (ret) {
1045 dev_warn(dev, "%s: Governor %s start=%d\n",
1046 __func__, devfreq->governor->name,
1047 ret);
1048 }
1049 }
1050 }
1051
1052err_out:
1053 mutex_unlock(&devfreq_list_lock);
1054
1055 return err;
1056}
1057EXPORT_SYMBOL(devfreq_add_governor);
1058
1059/**
1060 * devfreq_remove_governor() - Remove devfreq feature from a device.
1061 * @governor: the devfreq governor to be removed
1062 */
1063int devfreq_remove_governor(struct devfreq_governor *governor)
1064{
1065 struct devfreq_governor *g;
1066 struct devfreq *devfreq;
1067 int err = 0;
1068
1069 if (!governor) {
1070 pr_err("%s: Invalid parameters.\n", __func__);
1071 return -EINVAL;
1072 }
1073
1074 mutex_lock(&devfreq_list_lock);
1075 g = find_devfreq_governor(governor->name);
1076 if (IS_ERR(g)) {
1077 pr_err("%s: governor %s not registered\n", __func__,
1078 governor->name);
1079 err = PTR_ERR(g);
1080 goto err_out;
1081 }
1082 list_for_each_entry(devfreq, &devfreq_list, node) {
1083 int ret;
1084 struct device *dev = devfreq->dev.parent;
1085
1086 if (!strncmp(devfreq->governor_name, governor->name,
1087 DEVFREQ_NAME_LEN)) {
1088 /* we should have a devfreq governor! */
1089 if (!devfreq->governor) {
1090 dev_warn(dev, "%s: Governor %s NOT present\n",
1091 __func__, governor->name);
1092 continue;
1093 /* Fall through */
1094 }
1095 ret = devfreq->governor->event_handler(devfreq,
1096 DEVFREQ_GOV_STOP, NULL);
1097 if (ret) {
1098 dev_warn(dev, "%s: Governor %s stop=%d\n",
1099 __func__, devfreq->governor->name,
1100 ret);
1101 }
1102 devfreq->governor = NULL;
1103 }
1104 }
1105
1106 list_del(&governor->node);
1107err_out:
1108 mutex_unlock(&devfreq_list_lock);
1109
1110 return err;
1111}
1112EXPORT_SYMBOL(devfreq_remove_governor);
1113
1114static ssize_t governor_show(struct device *dev,
1115 struct device_attribute *attr, char *buf)
1116{
1117 if (!to_devfreq(dev)->governor)
1118 return -EINVAL;
1119
1120 return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name);
1121}
1122
1123static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
1124 const char *buf, size_t count)
1125{
1126 struct devfreq *df = to_devfreq(dev);
1127 int ret;
1128 char str_governor[DEVFREQ_NAME_LEN + 1];
1129 const struct devfreq_governor *governor, *prev_governor;
1130
1131 ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
1132 if (ret != 1)
1133 return -EINVAL;
1134
1135 mutex_lock(&devfreq_list_lock);
1136 governor = try_then_request_governor(str_governor);
1137 if (IS_ERR(governor)) {
1138 ret = PTR_ERR(governor);
1139 goto out;
1140 }
1141 if (df->governor == governor) {
1142 ret = 0;
1143 goto out;
1144 } else if ((df->governor && df->governor->immutable) ||
1145 governor->immutable) {
1146 ret = -EINVAL;
1147 goto out;
1148 }
1149
1150 if (df->governor) {
1151 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
1152 if (ret) {
1153 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
1154 __func__, df->governor->name, ret);
1155 goto out;
1156 }
1157 }
1158 prev_governor = df->governor;
1159 df->governor = governor;
1160 strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
1161 ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1162 if (ret) {
1163 dev_warn(dev, "%s: Governor %s not started(%d)\n",
1164 __func__, df->governor->name, ret);
1165 df->governor = prev_governor;
1166 strncpy(df->governor_name, prev_governor->name,
1167 DEVFREQ_NAME_LEN);
1168 ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1169 if (ret) {
1170 dev_err(dev,
1171 "%s: reverting to Governor %s failed (%d)\n",
1172 __func__, df->governor_name, ret);
1173 df->governor = NULL;
1174 }
1175 }
1176out:
1177 mutex_unlock(&devfreq_list_lock);
1178
1179 if (!ret)
1180 ret = count;
1181 return ret;
1182}
1183static DEVICE_ATTR_RW(governor);
1184
1185static ssize_t available_governors_show(struct device *d,
1186 struct device_attribute *attr,
1187 char *buf)
1188{
1189 struct devfreq *df = to_devfreq(d);
1190 ssize_t count = 0;
1191
1192 mutex_lock(&devfreq_list_lock);
1193
1194 /*
1195 * The devfreq with immutable governor (e.g., passive) shows
1196 * only own governor.
1197 */
1198 if (df->governor->immutable) {
1199 count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
1200 "%s ", df->governor_name);
1201 /*
1202 * The devfreq device shows the registered governor except for
1203 * immutable governors such as passive governor .
1204 */
1205 } else {
1206 struct devfreq_governor *governor;
1207
1208 list_for_each_entry(governor, &devfreq_governor_list, node) {
1209 if (governor->immutable)
1210 continue;
1211 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1212 "%s ", governor->name);
1213 }
1214 }
1215
1216 mutex_unlock(&devfreq_list_lock);
1217
1218 /* Truncate the trailing space */
1219 if (count)
1220 count--;
1221
1222 count += sprintf(&buf[count], "\n");
1223
1224 return count;
1225}
1226static DEVICE_ATTR_RO(available_governors);
1227
1228static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
1229 char *buf)
1230{
1231 unsigned long freq;
1232 struct devfreq *devfreq = to_devfreq(dev);
1233
1234 if (devfreq->profile->get_cur_freq &&
1235 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
1236 return sprintf(buf, "%lu\n", freq);
1237
1238 return sprintf(buf, "%lu\n", devfreq->previous_freq);
1239}
1240static DEVICE_ATTR_RO(cur_freq);
1241
1242static ssize_t target_freq_show(struct device *dev,
1243 struct device_attribute *attr, char *buf)
1244{
1245 return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
1246}
1247static DEVICE_ATTR_RO(target_freq);
1248
1249static ssize_t polling_interval_show(struct device *dev,
1250 struct device_attribute *attr, char *buf)
1251{
1252 return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
1253}
1254
1255static ssize_t polling_interval_store(struct device *dev,
1256 struct device_attribute *attr,
1257 const char *buf, size_t count)
1258{
1259 struct devfreq *df = to_devfreq(dev);
1260 unsigned int value;
1261 int ret;
1262
1263 if (!df->governor)
1264 return -EINVAL;
1265
1266 ret = sscanf(buf, "%u", &value);
1267 if (ret != 1)
1268 return -EINVAL;
1269
1270 df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
1271 ret = count;
1272
1273 return ret;
1274}
1275static DEVICE_ATTR_RW(polling_interval);
1276
1277static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1278 const char *buf, size_t count)
1279{
1280 struct devfreq *df = to_devfreq(dev);
1281 unsigned long value;
1282 int ret;
1283
1284 ret = sscanf(buf, "%lu", &value);
1285 if (ret != 1)
1286 return -EINVAL;
1287
1288 mutex_lock(&df->lock);
1289
1290 if (value) {
1291 if (value > df->max_freq) {
1292 ret = -EINVAL;
1293 goto unlock;
1294 }
1295 } else {
1296 unsigned long *freq_table = df->profile->freq_table;
1297
1298 /* Get minimum frequency according to sorting order */
1299 if (freq_table[0] < freq_table[df->profile->max_state - 1])
1300 value = freq_table[0];
1301 else
1302 value = freq_table[df->profile->max_state - 1];
1303 }
1304
1305 df->min_freq = value;
1306 update_devfreq(df);
1307 ret = count;
1308unlock:
1309 mutex_unlock(&df->lock);
1310 return ret;
1311}
1312
1313static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
1314 char *buf)
1315{
1316 struct devfreq *df = to_devfreq(dev);
1317
1318 return sprintf(buf, "%lu\n", max(df->scaling_min_freq, df->min_freq));
1319}
1320
1321static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1322 const char *buf, size_t count)
1323{
1324 struct devfreq *df = to_devfreq(dev);
1325 unsigned long value;
1326 int ret;
1327
1328 ret = sscanf(buf, "%lu", &value);
1329 if (ret != 1)
1330 return -EINVAL;
1331
1332 mutex_lock(&df->lock);
1333
1334 if (value) {
1335 if (value < df->min_freq) {
1336 ret = -EINVAL;
1337 goto unlock;
1338 }
1339 } else {
1340 unsigned long *freq_table = df->profile->freq_table;
1341
1342 /* Get maximum frequency according to sorting order */
1343 if (freq_table[0] < freq_table[df->profile->max_state - 1])
1344 value = freq_table[df->profile->max_state - 1];
1345 else
1346 value = freq_table[0];
1347 }
1348
1349 df->max_freq = value;
1350 update_devfreq(df);
1351 ret = count;
1352unlock:
1353 mutex_unlock(&df->lock);
1354 return ret;
1355}
1356static DEVICE_ATTR_RW(min_freq);
1357
1358static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
1359 char *buf)
1360{
1361 struct devfreq *df = to_devfreq(dev);
1362
1363 return sprintf(buf, "%lu\n", min(df->scaling_max_freq, df->max_freq));
1364}
1365static DEVICE_ATTR_RW(max_freq);
1366
1367static ssize_t available_frequencies_show(struct device *d,
1368 struct device_attribute *attr,
1369 char *buf)
1370{
1371 struct devfreq *df = to_devfreq(d);
1372 ssize_t count = 0;
1373 int i;
1374
1375 mutex_lock(&df->lock);
1376
1377 for (i = 0; i < df->profile->max_state; i++)
1378 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1379 "%lu ", df->profile->freq_table[i]);
1380
1381 mutex_unlock(&df->lock);
1382 /* Truncate the trailing space */
1383 if (count)
1384 count--;
1385
1386 count += sprintf(&buf[count], "\n");
1387
1388 return count;
1389}
1390static DEVICE_ATTR_RO(available_frequencies);
1391
1392static ssize_t trans_stat_show(struct device *dev,
1393 struct device_attribute *attr, char *buf)
1394{
1395 struct devfreq *devfreq = to_devfreq(dev);
1396 ssize_t len;
1397 int i, j;
1398 unsigned int max_state = devfreq->profile->max_state;
1399
1400 if (!devfreq->stop_polling &&
1401 devfreq_update_status(devfreq, devfreq->previous_freq))
1402 return 0;
1403 if (max_state == 0)
1404 return sprintf(buf, "Not Supported.\n");
1405
1406 len = sprintf(buf, " From : To\n");
1407 len += sprintf(buf + len, " :");
1408 for (i = 0; i < max_state; i++)
1409 len += sprintf(buf + len, "%10lu",
1410 devfreq->profile->freq_table[i]);
1411
1412 len += sprintf(buf + len, " time(ms)\n");
1413
1414 for (i = 0; i < max_state; i++) {
1415 if (devfreq->profile->freq_table[i]
1416 == devfreq->previous_freq) {
1417 len += sprintf(buf + len, "*");
1418 } else {
1419 len += sprintf(buf + len, " ");
1420 }
1421 len += sprintf(buf + len, "%10lu:",
1422 devfreq->profile->freq_table[i]);
1423 for (j = 0; j < max_state; j++)
1424 len += sprintf(buf + len, "%10u",
1425 devfreq->trans_table[(i * max_state) + j]);
1426 len += sprintf(buf + len, "%10u\n",
1427 jiffies_to_msecs(devfreq->time_in_state[i]));
1428 }
1429
1430 len += sprintf(buf + len, "Total transition : %u\n",
1431 devfreq->total_trans);
1432 return len;
1433}
1434static DEVICE_ATTR_RO(trans_stat);
1435
1436static struct attribute *devfreq_attrs[] = {
1437 &dev_attr_governor.attr,
1438 &dev_attr_available_governors.attr,
1439 &dev_attr_cur_freq.attr,
1440 &dev_attr_available_frequencies.attr,
1441 &dev_attr_target_freq.attr,
1442 &dev_attr_polling_interval.attr,
1443 &dev_attr_min_freq.attr,
1444 &dev_attr_max_freq.attr,
1445 &dev_attr_trans_stat.attr,
1446 NULL,
1447};
1448ATTRIBUTE_GROUPS(devfreq);
1449
1450static int __init devfreq_init(void)
1451{
1452 devfreq_class = class_create(THIS_MODULE, "devfreq");
1453 if (IS_ERR(devfreq_class)) {
1454 pr_err("%s: couldn't create class\n", __FILE__);
1455 return PTR_ERR(devfreq_class);
1456 }
1457
1458 devfreq_wq = create_freezable_workqueue("devfreq_wq");
1459 if (!devfreq_wq) {
1460 class_destroy(devfreq_class);
1461 pr_err("%s: couldn't create workqueue\n", __FILE__);
1462 return -ENOMEM;
1463 }
1464 devfreq_class->dev_groups = devfreq_groups;
1465
1466 return 0;
1467}
1468subsys_initcall(devfreq_init);
1469
1470/*
1471 * The following are helper functions for devfreq user device drivers with
1472 * OPP framework.
1473 */
1474
1475/**
1476 * devfreq_recommended_opp() - Helper function to get proper OPP for the
1477 * freq value given to target callback.
1478 * @dev: The devfreq user device. (parent of devfreq)
1479 * @freq: The frequency given to target function
1480 * @flags: Flags handed from devfreq framework.
1481 *
1482 * The callers are required to call dev_pm_opp_put() for the returned OPP after
1483 * use.
1484 */
1485struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1486 unsigned long *freq,
1487 u32 flags)
1488{
1489 struct dev_pm_opp *opp;
1490
1491 if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1492 /* The freq is an upper bound. opp should be lower */
1493 opp = dev_pm_opp_find_freq_floor(dev, freq);
1494
1495 /* If not available, use the closest opp */
1496 if (opp == ERR_PTR(-ERANGE))
1497 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1498 } else {
1499 /* The freq is an lower bound. opp should be higher */
1500 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1501
1502 /* If not available, use the closest opp */
1503 if (opp == ERR_PTR(-ERANGE))
1504 opp = dev_pm_opp_find_freq_floor(dev, freq);
1505 }
1506
1507 return opp;
1508}
1509EXPORT_SYMBOL(devfreq_recommended_opp);
1510
1511/**
1512 * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1513 * for any changes in the OPP availability
1514 * changes
1515 * @dev: The devfreq user device. (parent of devfreq)
1516 * @devfreq: The devfreq object.
1517 */
1518int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1519{
1520 return dev_pm_opp_register_notifier(dev, &devfreq->nb);
1521}
1522EXPORT_SYMBOL(devfreq_register_opp_notifier);
1523
1524/**
1525 * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1526 * notified for any changes in the OPP
1527 * availability changes anymore.
1528 * @dev: The devfreq user device. (parent of devfreq)
1529 * @devfreq: The devfreq object.
1530 *
1531 * At exit() callback of devfreq_dev_profile, this must be included if
1532 * devfreq_recommended_opp is used.
1533 */
1534int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1535{
1536 return dev_pm_opp_unregister_notifier(dev, &devfreq->nb);
1537}
1538EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
1539
1540static void devm_devfreq_opp_release(struct device *dev, void *res)
1541{
1542 devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
1543}
1544
1545/**
1546 * devm_devfreq_register_opp_notifier() - Resource-managed
1547 * devfreq_register_opp_notifier()
1548 * @dev: The devfreq user device. (parent of devfreq)
1549 * @devfreq: The devfreq object.
1550 */
1551int devm_devfreq_register_opp_notifier(struct device *dev,
1552 struct devfreq *devfreq)
1553{
1554 struct devfreq **ptr;
1555 int ret;
1556
1557 ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
1558 if (!ptr)
1559 return -ENOMEM;
1560
1561 ret = devfreq_register_opp_notifier(dev, devfreq);
1562 if (ret) {
1563 devres_free(ptr);
1564 return ret;
1565 }
1566
1567 *ptr = devfreq;
1568 devres_add(dev, ptr);
1569
1570 return 0;
1571}
1572EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
1573
1574/**
1575 * devm_devfreq_unregister_opp_notifier() - Resource-managed
1576 * devfreq_unregister_opp_notifier()
1577 * @dev: The devfreq user device. (parent of devfreq)
1578 * @devfreq: The devfreq object.
1579 */
1580void devm_devfreq_unregister_opp_notifier(struct device *dev,
1581 struct devfreq *devfreq)
1582{
1583 WARN_ON(devres_release(dev, devm_devfreq_opp_release,
1584 devm_devfreq_dev_match, devfreq));
1585}
1586EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
1587
1588/**
1589 * devfreq_register_notifier() - Register a driver with devfreq
1590 * @devfreq: The devfreq object.
1591 * @nb: The notifier block to register.
1592 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1593 */
1594int devfreq_register_notifier(struct devfreq *devfreq,
1595 struct notifier_block *nb,
1596 unsigned int list)
1597{
1598 int ret = 0;
1599
1600 if (!devfreq)
1601 return -EINVAL;
1602
1603 switch (list) {
1604 case DEVFREQ_TRANSITION_NOTIFIER:
1605 ret = srcu_notifier_chain_register(
1606 &devfreq->transition_notifier_list, nb);
1607 break;
1608 default:
1609 ret = -EINVAL;
1610 }
1611
1612 return ret;
1613}
1614EXPORT_SYMBOL(devfreq_register_notifier);
1615
1616/*
1617 * devfreq_unregister_notifier() - Unregister a driver with devfreq
1618 * @devfreq: The devfreq object.
1619 * @nb: The notifier block to be unregistered.
1620 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1621 */
1622int devfreq_unregister_notifier(struct devfreq *devfreq,
1623 struct notifier_block *nb,
1624 unsigned int list)
1625{
1626 int ret = 0;
1627
1628 if (!devfreq)
1629 return -EINVAL;
1630
1631 switch (list) {
1632 case DEVFREQ_TRANSITION_NOTIFIER:
1633 ret = srcu_notifier_chain_unregister(
1634 &devfreq->transition_notifier_list, nb);
1635 break;
1636 default:
1637 ret = -EINVAL;
1638 }
1639
1640 return ret;
1641}
1642EXPORT_SYMBOL(devfreq_unregister_notifier);
1643
1644struct devfreq_notifier_devres {
1645 struct devfreq *devfreq;
1646 struct notifier_block *nb;
1647 unsigned int list;
1648};
1649
1650static void devm_devfreq_notifier_release(struct device *dev, void *res)
1651{
1652 struct devfreq_notifier_devres *this = res;
1653
1654 devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
1655}
1656
1657/**
1658 * devm_devfreq_register_notifier()
1659 - Resource-managed devfreq_register_notifier()
1660 * @dev: The devfreq user device. (parent of devfreq)
1661 * @devfreq: The devfreq object.
1662 * @nb: The notifier block to be unregistered.
1663 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1664 */
1665int devm_devfreq_register_notifier(struct device *dev,
1666 struct devfreq *devfreq,
1667 struct notifier_block *nb,
1668 unsigned int list)
1669{
1670 struct devfreq_notifier_devres *ptr;
1671 int ret;
1672
1673 ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
1674 GFP_KERNEL);
1675 if (!ptr)
1676 return -ENOMEM;
1677
1678 ret = devfreq_register_notifier(devfreq, nb, list);
1679 if (ret) {
1680 devres_free(ptr);
1681 return ret;
1682 }
1683
1684 ptr->devfreq = devfreq;
1685 ptr->nb = nb;
1686 ptr->list = list;
1687 devres_add(dev, ptr);
1688
1689 return 0;
1690}
1691EXPORT_SYMBOL(devm_devfreq_register_notifier);
1692
1693/**
1694 * devm_devfreq_unregister_notifier()
1695 - Resource-managed devfreq_unregister_notifier()
1696 * @dev: The devfreq user device. (parent of devfreq)
1697 * @devfreq: The devfreq object.
1698 * @nb: The notifier block to be unregistered.
1699 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1700 */
1701void devm_devfreq_unregister_notifier(struct device *dev,
1702 struct devfreq *devfreq,
1703 struct notifier_block *nb,
1704 unsigned int list)
1705{
1706 WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
1707 devm_devfreq_dev_match, devfreq));
1708}
1709EXPORT_SYMBOL(devm_devfreq_unregister_notifier);