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