projects/linux·blob v3.8 · refs

1078 lines · 27.6 KiB

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