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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Devices PM QoS constraints management
4 *
5 * Copyright (C) 2011 Texas Instruments, Inc.
6 *
7 * This module exposes the interface to kernel space for specifying
8 * per-device PM QoS dependencies. It provides infrastructure for registration
9 * of:
10 *
11 * Dependents on a QoS value : register requests
12 * Watchers of QoS value : get notified when target QoS value changes
13 *
14 * This QoS design is best effort based. Dependents register their QoS needs.
15 * Watchers register to keep track of the current QoS needs of the system.
16 * Watchers can register a per-device notification callback using the
17 * dev_pm_qos_*_notifier API. The notification chain data is stored in the
18 * per-device constraint data struct.
19 *
20 * Note about the per-device constraint data struct allocation:
21 * . The per-device constraints data struct ptr is stored into the device
22 * dev_pm_info.
23 * . To minimize the data usage by the per-device constraints, the data struct
24 * is only allocated at the first call to dev_pm_qos_add_request.
25 * . The data is later free'd when the device is removed from the system.
26 * . A global mutex protects the constraints users from the data being
27 * allocated and free'd.
28 */
29
30#include <linux/pm_qos.h>
31#include <linux/spinlock.h>
32#include <linux/slab.h>
33#include <linux/device.h>
34#include <linux/mutex.h>
35#include <linux/export.h>
36#include <linux/pm_runtime.h>
37#include <linux/err.h>
38#include <trace/events/power.h>
39
40#include "power.h"
41
42static DEFINE_MUTEX(dev_pm_qos_mtx);
43static DEFINE_MUTEX(dev_pm_qos_sysfs_mtx);
44
45/**
46 * __dev_pm_qos_flags - Check PM QoS flags for a given device.
47 * @dev: Device to check the PM QoS flags for.
48 * @mask: Flags to check against.
49 *
50 * This routine must be called with dev->power.lock held.
51 */
52enum pm_qos_flags_status __dev_pm_qos_flags(struct device *dev, s32 mask)
53{
54 struct dev_pm_qos *qos = dev->power.qos;
55 struct pm_qos_flags *pqf;
56 s32 val;
57
58 lockdep_assert_held(&dev->power.lock);
59
60 if (IS_ERR_OR_NULL(qos))
61 return PM_QOS_FLAGS_UNDEFINED;
62
63 pqf = &qos->flags;
64 if (list_empty(&pqf->list))
65 return PM_QOS_FLAGS_UNDEFINED;
66
67 val = pqf->effective_flags & mask;
68 if (val)
69 return (val == mask) ? PM_QOS_FLAGS_ALL : PM_QOS_FLAGS_SOME;
70
71 return PM_QOS_FLAGS_NONE;
72}
73
74/**
75 * dev_pm_qos_flags - Check PM QoS flags for a given device (locked).
76 * @dev: Device to check the PM QoS flags for.
77 * @mask: Flags to check against.
78 */
79enum pm_qos_flags_status dev_pm_qos_flags(struct device *dev, s32 mask)
80{
81 unsigned long irqflags;
82 enum pm_qos_flags_status ret;
83
84 spin_lock_irqsave(&dev->power.lock, irqflags);
85 ret = __dev_pm_qos_flags(dev, mask);
86 spin_unlock_irqrestore(&dev->power.lock, irqflags);
87
88 return ret;
89}
90EXPORT_SYMBOL_GPL(dev_pm_qos_flags);
91
92/**
93 * __dev_pm_qos_resume_latency - Get resume latency constraint for a given device.
94 * @dev: Device to get the PM QoS constraint value for.
95 *
96 * This routine must be called with dev->power.lock held.
97 */
98s32 __dev_pm_qos_resume_latency(struct device *dev)
99{
100 lockdep_assert_held(&dev->power.lock);
101
102 return dev_pm_qos_raw_resume_latency(dev);
103}
104
105/**
106 * dev_pm_qos_read_value - Get PM QoS constraint for a given device (locked).
107 * @dev: Device to get the PM QoS constraint value for.
108 * @type: QoS request type.
109 */
110s32 dev_pm_qos_read_value(struct device *dev, enum dev_pm_qos_req_type type)
111{
112 struct dev_pm_qos *qos = dev->power.qos;
113 unsigned long flags;
114 s32 ret;
115
116 spin_lock_irqsave(&dev->power.lock, flags);
117
118 switch (type) {
119 case DEV_PM_QOS_RESUME_LATENCY:
120 ret = IS_ERR_OR_NULL(qos) ? PM_QOS_RESUME_LATENCY_NO_CONSTRAINT
121 : pm_qos_read_value(&qos->resume_latency);
122 break;
123 case DEV_PM_QOS_MIN_FREQUENCY:
124 ret = IS_ERR_OR_NULL(qos) ? PM_QOS_MIN_FREQUENCY_DEFAULT_VALUE
125 : freq_qos_read_value(&qos->freq, FREQ_QOS_MIN);
126 break;
127 case DEV_PM_QOS_MAX_FREQUENCY:
128 ret = IS_ERR_OR_NULL(qos) ? PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE
129 : freq_qos_read_value(&qos->freq, FREQ_QOS_MAX);
130 break;
131 default:
132 WARN_ON(1);
133 ret = 0;
134 }
135
136 spin_unlock_irqrestore(&dev->power.lock, flags);
137
138 return ret;
139}
140
141/**
142 * apply_constraint - Add/modify/remove device PM QoS request.
143 * @req: Constraint request to apply
144 * @action: Action to perform (add/update/remove).
145 * @value: Value to assign to the QoS request.
146 *
147 * Internal function to update the constraints list using the PM QoS core
148 * code and if needed call the per-device callbacks.
149 */
150static int apply_constraint(struct dev_pm_qos_request *req,
151 enum pm_qos_req_action action, s32 value)
152{
153 struct dev_pm_qos *qos = req->dev->power.qos;
154 int ret;
155
156 switch(req->type) {
157 case DEV_PM_QOS_RESUME_LATENCY:
158 if (WARN_ON(action != PM_QOS_REMOVE_REQ && value < 0))
159 value = 0;
160
161 ret = pm_qos_update_target(&qos->resume_latency,
162 &req->data.pnode, action, value);
163 break;
164 case DEV_PM_QOS_LATENCY_TOLERANCE:
165 ret = pm_qos_update_target(&qos->latency_tolerance,
166 &req->data.pnode, action, value);
167 if (ret) {
168 value = pm_qos_read_value(&qos->latency_tolerance);
169 req->dev->power.set_latency_tolerance(req->dev, value);
170 }
171 break;
172 case DEV_PM_QOS_MIN_FREQUENCY:
173 case DEV_PM_QOS_MAX_FREQUENCY:
174 ret = freq_qos_apply(&req->data.freq, action, value);
175 break;
176 case DEV_PM_QOS_FLAGS:
177 ret = pm_qos_update_flags(&qos->flags, &req->data.flr,
178 action, value);
179 break;
180 default:
181 ret = -EINVAL;
182 }
183
184 return ret;
185}
186
187/*
188 * dev_pm_qos_constraints_allocate
189 * @dev: device to allocate data for
190 *
191 * Called at the first call to add_request, for constraint data allocation
192 * Must be called with the dev_pm_qos_mtx mutex held
193 */
194static int dev_pm_qos_constraints_allocate(struct device *dev)
195{
196 struct dev_pm_qos *qos;
197 struct pm_qos_constraints *c;
198 struct blocking_notifier_head *n;
199
200 qos = kzalloc(sizeof(*qos), GFP_KERNEL);
201 if (!qos)
202 return -ENOMEM;
203
204 n = kcalloc(3, sizeof(*n), GFP_KERNEL);
205 if (!n) {
206 kfree(qos);
207 return -ENOMEM;
208 }
209
210 c = &qos->resume_latency;
211 plist_head_init(&c->list);
212 c->target_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;
213 c->default_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;
214 c->no_constraint_value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT;
215 c->type = PM_QOS_MIN;
216 c->notifiers = n;
217 BLOCKING_INIT_NOTIFIER_HEAD(n);
218
219 c = &qos->latency_tolerance;
220 plist_head_init(&c->list);
221 c->target_value = PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE;
222 c->default_value = PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE;
223 c->no_constraint_value = PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT;
224 c->type = PM_QOS_MIN;
225
226 freq_constraints_init(&qos->freq);
227
228 INIT_LIST_HEAD(&qos->flags.list);
229
230 spin_lock_irq(&dev->power.lock);
231 dev->power.qos = qos;
232 spin_unlock_irq(&dev->power.lock);
233
234 return 0;
235}
236
237static void __dev_pm_qos_hide_latency_limit(struct device *dev);
238static void __dev_pm_qos_hide_flags(struct device *dev);
239
240/**
241 * dev_pm_qos_constraints_destroy
242 * @dev: target device
243 *
244 * Called from the device PM subsystem on device removal under device_pm_lock().
245 */
246void dev_pm_qos_constraints_destroy(struct device *dev)
247{
248 struct dev_pm_qos *qos;
249 struct dev_pm_qos_request *req, *tmp;
250 struct pm_qos_constraints *c;
251 struct pm_qos_flags *f;
252
253 mutex_lock(&dev_pm_qos_sysfs_mtx);
254
255 /*
256 * If the device's PM QoS resume latency limit or PM QoS flags have been
257 * exposed to user space, they have to be hidden at this point.
258 */
259 pm_qos_sysfs_remove_resume_latency(dev);
260 pm_qos_sysfs_remove_flags(dev);
261
262 mutex_lock(&dev_pm_qos_mtx);
263
264 __dev_pm_qos_hide_latency_limit(dev);
265 __dev_pm_qos_hide_flags(dev);
266
267 qos = dev->power.qos;
268 if (!qos)
269 goto out;
270
271 /* Flush the constraints lists for the device. */
272 c = &qos->resume_latency;
273 plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) {
274 /*
275 * Update constraints list and call the notification
276 * callbacks if needed
277 */
278 apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
279 memset(req, 0, sizeof(*req));
280 }
281
282 c = &qos->latency_tolerance;
283 plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) {
284 apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
285 memset(req, 0, sizeof(*req));
286 }
287
288 c = &qos->freq.min_freq;
289 plist_for_each_entry_safe(req, tmp, &c->list, data.freq.pnode) {
290 apply_constraint(req, PM_QOS_REMOVE_REQ,
291 PM_QOS_MIN_FREQUENCY_DEFAULT_VALUE);
292 memset(req, 0, sizeof(*req));
293 }
294
295 c = &qos->freq.max_freq;
296 plist_for_each_entry_safe(req, tmp, &c->list, data.freq.pnode) {
297 apply_constraint(req, PM_QOS_REMOVE_REQ,
298 PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
299 memset(req, 0, sizeof(*req));
300 }
301
302 f = &qos->flags;
303 list_for_each_entry_safe(req, tmp, &f->list, data.flr.node) {
304 apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
305 memset(req, 0, sizeof(*req));
306 }
307
308 spin_lock_irq(&dev->power.lock);
309 dev->power.qos = ERR_PTR(-ENODEV);
310 spin_unlock_irq(&dev->power.lock);
311
312 kfree(qos->resume_latency.notifiers);
313 kfree(qos);
314
315 out:
316 mutex_unlock(&dev_pm_qos_mtx);
317
318 mutex_unlock(&dev_pm_qos_sysfs_mtx);
319}
320
321static bool dev_pm_qos_invalid_req_type(struct device *dev,
322 enum dev_pm_qos_req_type type)
323{
324 return type == DEV_PM_QOS_LATENCY_TOLERANCE &&
325 !dev->power.set_latency_tolerance;
326}
327
328static int __dev_pm_qos_add_request(struct device *dev,
329 struct dev_pm_qos_request *req,
330 enum dev_pm_qos_req_type type, s32 value)
331{
332 int ret = 0;
333
334 if (!dev || !req || dev_pm_qos_invalid_req_type(dev, type))
335 return -EINVAL;
336
337 if (WARN(dev_pm_qos_request_active(req),
338 "%s() called for already added request\n", __func__))
339 return -EINVAL;
340
341 if (IS_ERR(dev->power.qos))
342 ret = -ENODEV;
343 else if (!dev->power.qos)
344 ret = dev_pm_qos_constraints_allocate(dev);
345
346 trace_dev_pm_qos_add_request(dev_name(dev), type, value);
347 if (ret)
348 return ret;
349
350 req->dev = dev;
351 req->type = type;
352 if (req->type == DEV_PM_QOS_MIN_FREQUENCY)
353 ret = freq_qos_add_request(&dev->power.qos->freq,
354 &req->data.freq,
355 FREQ_QOS_MIN, value);
356 else if (req->type == DEV_PM_QOS_MAX_FREQUENCY)
357 ret = freq_qos_add_request(&dev->power.qos->freq,
358 &req->data.freq,
359 FREQ_QOS_MAX, value);
360 else
361 ret = apply_constraint(req, PM_QOS_ADD_REQ, value);
362
363 return ret;
364}
365
366/**
367 * dev_pm_qos_add_request - inserts new qos request into the list
368 * @dev: target device for the constraint
369 * @req: pointer to a preallocated handle
370 * @type: type of the request
371 * @value: defines the qos request
372 *
373 * This function inserts a new entry in the device constraints list of
374 * requested qos performance characteristics. It recomputes the aggregate
375 * QoS expectations of parameters and initializes the dev_pm_qos_request
376 * handle. Caller needs to save this handle for later use in updates and
377 * removal.
378 *
379 * Returns 1 if the aggregated constraint value has changed,
380 * 0 if the aggregated constraint value has not changed,
381 * -EINVAL in case of wrong parameters, -ENOMEM if there's not enough memory
382 * to allocate for data structures, -ENODEV if the device has just been removed
383 * from the system.
384 *
385 * Callers should ensure that the target device is not RPM_SUSPENDED before
386 * using this function for requests of type DEV_PM_QOS_FLAGS.
387 */
388int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
389 enum dev_pm_qos_req_type type, s32 value)
390{
391 int ret;
392
393 mutex_lock(&dev_pm_qos_mtx);
394 ret = __dev_pm_qos_add_request(dev, req, type, value);
395 mutex_unlock(&dev_pm_qos_mtx);
396 return ret;
397}
398EXPORT_SYMBOL_GPL(dev_pm_qos_add_request);
399
400/**
401 * __dev_pm_qos_update_request - Modify an existing device PM QoS request.
402 * @req : PM QoS request to modify.
403 * @new_value: New value to request.
404 */
405static int __dev_pm_qos_update_request(struct dev_pm_qos_request *req,
406 s32 new_value)
407{
408 s32 curr_value;
409 int ret = 0;
410
411 if (!req) /*guard against callers passing in null */
412 return -EINVAL;
413
414 if (WARN(!dev_pm_qos_request_active(req),
415 "%s() called for unknown object\n", __func__))
416 return -EINVAL;
417
418 if (IS_ERR_OR_NULL(req->dev->power.qos))
419 return -ENODEV;
420
421 switch(req->type) {
422 case DEV_PM_QOS_RESUME_LATENCY:
423 case DEV_PM_QOS_LATENCY_TOLERANCE:
424 curr_value = req->data.pnode.prio;
425 break;
426 case DEV_PM_QOS_MIN_FREQUENCY:
427 case DEV_PM_QOS_MAX_FREQUENCY:
428 curr_value = req->data.freq.pnode.prio;
429 break;
430 case DEV_PM_QOS_FLAGS:
431 curr_value = req->data.flr.flags;
432 break;
433 default:
434 return -EINVAL;
435 }
436
437 trace_dev_pm_qos_update_request(dev_name(req->dev), req->type,
438 new_value);
439 if (curr_value != new_value)
440 ret = apply_constraint(req, PM_QOS_UPDATE_REQ, new_value);
441
442 return ret;
443}
444
445/**
446 * dev_pm_qos_update_request - modifies an existing qos request
447 * @req : handle to list element holding a dev_pm_qos request to use
448 * @new_value: defines the qos request
449 *
450 * Updates an existing dev PM qos request along with updating the
451 * target value.
452 *
453 * Attempts are made to make this code callable on hot code paths.
454 *
455 * Returns 1 if the aggregated constraint value has changed,
456 * 0 if the aggregated constraint value has not changed,
457 * -EINVAL in case of wrong parameters, -ENODEV if the device has been
458 * removed from the system
459 *
460 * Callers should ensure that the target device is not RPM_SUSPENDED before
461 * using this function for requests of type DEV_PM_QOS_FLAGS.
462 */
463int dev_pm_qos_update_request(struct dev_pm_qos_request *req, s32 new_value)
464{
465 int ret;
466
467 mutex_lock(&dev_pm_qos_mtx);
468 ret = __dev_pm_qos_update_request(req, new_value);
469 mutex_unlock(&dev_pm_qos_mtx);
470 return ret;
471}
472EXPORT_SYMBOL_GPL(dev_pm_qos_update_request);
473
474static int __dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
475{
476 int ret;
477
478 if (!req) /*guard against callers passing in null */
479 return -EINVAL;
480
481 if (WARN(!dev_pm_qos_request_active(req),
482 "%s() called for unknown object\n", __func__))
483 return -EINVAL;
484
485 if (IS_ERR_OR_NULL(req->dev->power.qos))
486 return -ENODEV;
487
488 trace_dev_pm_qos_remove_request(dev_name(req->dev), req->type,
489 PM_QOS_DEFAULT_VALUE);
490 ret = apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
491 memset(req, 0, sizeof(*req));
492 return ret;
493}
494
495/**
496 * dev_pm_qos_remove_request - modifies an existing qos request
497 * @req: handle to request list element
498 *
499 * Will remove pm qos request from the list of constraints and
500 * recompute the current target value. Call this on slow code paths.
501 *
502 * Returns 1 if the aggregated constraint value has changed,
503 * 0 if the aggregated constraint value has not changed,
504 * -EINVAL in case of wrong parameters, -ENODEV if the device has been
505 * removed from the system
506 *
507 * Callers should ensure that the target device is not RPM_SUSPENDED before
508 * using this function for requests of type DEV_PM_QOS_FLAGS.
509 */
510int dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
511{
512 int ret;
513
514 mutex_lock(&dev_pm_qos_mtx);
515 ret = __dev_pm_qos_remove_request(req);
516 mutex_unlock(&dev_pm_qos_mtx);
517 return ret;
518}
519EXPORT_SYMBOL_GPL(dev_pm_qos_remove_request);
520
521/**
522 * dev_pm_qos_add_notifier - sets notification entry for changes to target value
523 * of per-device PM QoS constraints
524 *
525 * @dev: target device for the constraint
526 * @notifier: notifier block managed by caller.
527 * @type: request type.
528 *
529 * Will register the notifier into a notification chain that gets called
530 * upon changes to the target value for the device.
531 *
532 * If the device's constraints object doesn't exist when this routine is called,
533 * it will be created (or error code will be returned if that fails).
534 */
535int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier,
536 enum dev_pm_qos_req_type type)
537{
538 int ret = 0;
539
540 mutex_lock(&dev_pm_qos_mtx);
541
542 if (IS_ERR(dev->power.qos))
543 ret = -ENODEV;
544 else if (!dev->power.qos)
545 ret = dev_pm_qos_constraints_allocate(dev);
546
547 if (ret)
548 goto unlock;
549
550 switch (type) {
551 case DEV_PM_QOS_RESUME_LATENCY:
552 ret = blocking_notifier_chain_register(dev->power.qos->resume_latency.notifiers,
553 notifier);
554 break;
555 case DEV_PM_QOS_MIN_FREQUENCY:
556 ret = freq_qos_add_notifier(&dev->power.qos->freq,
557 FREQ_QOS_MIN, notifier);
558 break;
559 case DEV_PM_QOS_MAX_FREQUENCY:
560 ret = freq_qos_add_notifier(&dev->power.qos->freq,
561 FREQ_QOS_MAX, notifier);
562 break;
563 default:
564 WARN_ON(1);
565 ret = -EINVAL;
566 }
567
568unlock:
569 mutex_unlock(&dev_pm_qos_mtx);
570 return ret;
571}
572EXPORT_SYMBOL_GPL(dev_pm_qos_add_notifier);
573
574/**
575 * dev_pm_qos_remove_notifier - deletes notification for changes to target value
576 * of per-device PM QoS constraints
577 *
578 * @dev: target device for the constraint
579 * @notifier: notifier block to be removed.
580 * @type: request type.
581 *
582 * Will remove the notifier from the notification chain that gets called
583 * upon changes to the target value.
584 */
585int dev_pm_qos_remove_notifier(struct device *dev,
586 struct notifier_block *notifier,
587 enum dev_pm_qos_req_type type)
588{
589 int ret = 0;
590
591 mutex_lock(&dev_pm_qos_mtx);
592
593 /* Silently return if the constraints object is not present. */
594 if (IS_ERR_OR_NULL(dev->power.qos))
595 goto unlock;
596
597 switch (type) {
598 case DEV_PM_QOS_RESUME_LATENCY:
599 ret = blocking_notifier_chain_unregister(dev->power.qos->resume_latency.notifiers,
600 notifier);
601 break;
602 case DEV_PM_QOS_MIN_FREQUENCY:
603 ret = freq_qos_remove_notifier(&dev->power.qos->freq,
604 FREQ_QOS_MIN, notifier);
605 break;
606 case DEV_PM_QOS_MAX_FREQUENCY:
607 ret = freq_qos_remove_notifier(&dev->power.qos->freq,
608 FREQ_QOS_MAX, notifier);
609 break;
610 default:
611 WARN_ON(1);
612 ret = -EINVAL;
613 }
614
615unlock:
616 mutex_unlock(&dev_pm_qos_mtx);
617 return ret;
618}
619EXPORT_SYMBOL_GPL(dev_pm_qos_remove_notifier);
620
621/**
622 * dev_pm_qos_add_ancestor_request - Add PM QoS request for device's ancestor.
623 * @dev: Device whose ancestor to add the request for.
624 * @req: Pointer to the preallocated handle.
625 * @type: Type of the request.
626 * @value: Constraint latency value.
627 */
628int dev_pm_qos_add_ancestor_request(struct device *dev,
629 struct dev_pm_qos_request *req,
630 enum dev_pm_qos_req_type type, s32 value)
631{
632 struct device *ancestor = dev->parent;
633 int ret = -ENODEV;
634
635 switch (type) {
636 case DEV_PM_QOS_RESUME_LATENCY:
637 while (ancestor && !ancestor->power.ignore_children)
638 ancestor = ancestor->parent;
639
640 break;
641 case DEV_PM_QOS_LATENCY_TOLERANCE:
642 while (ancestor && !ancestor->power.set_latency_tolerance)
643 ancestor = ancestor->parent;
644
645 break;
646 default:
647 ancestor = NULL;
648 }
649 if (ancestor)
650 ret = dev_pm_qos_add_request(ancestor, req, type, value);
651
652 if (ret < 0)
653 req->dev = NULL;
654
655 return ret;
656}
657EXPORT_SYMBOL_GPL(dev_pm_qos_add_ancestor_request);
658
659static void __dev_pm_qos_drop_user_request(struct device *dev,
660 enum dev_pm_qos_req_type type)
661{
662 struct dev_pm_qos_request *req = NULL;
663
664 switch(type) {
665 case DEV_PM_QOS_RESUME_LATENCY:
666 req = dev->power.qos->resume_latency_req;
667 dev->power.qos->resume_latency_req = NULL;
668 break;
669 case DEV_PM_QOS_LATENCY_TOLERANCE:
670 req = dev->power.qos->latency_tolerance_req;
671 dev->power.qos->latency_tolerance_req = NULL;
672 break;
673 case DEV_PM_QOS_FLAGS:
674 req = dev->power.qos->flags_req;
675 dev->power.qos->flags_req = NULL;
676 break;
677 default:
678 WARN_ON(1);
679 return;
680 }
681 __dev_pm_qos_remove_request(req);
682 kfree(req);
683}
684
685static void dev_pm_qos_drop_user_request(struct device *dev,
686 enum dev_pm_qos_req_type type)
687{
688 mutex_lock(&dev_pm_qos_mtx);
689 __dev_pm_qos_drop_user_request(dev, type);
690 mutex_unlock(&dev_pm_qos_mtx);
691}
692
693/**
694 * dev_pm_qos_expose_latency_limit - Expose PM QoS latency limit to user space.
695 * @dev: Device whose PM QoS latency limit is to be exposed to user space.
696 * @value: Initial value of the latency limit.
697 */
698int dev_pm_qos_expose_latency_limit(struct device *dev, s32 value)
699{
700 struct dev_pm_qos_request *req;
701 int ret;
702
703 if (!device_is_registered(dev) || value < 0)
704 return -EINVAL;
705
706 req = kzalloc(sizeof(*req), GFP_KERNEL);
707 if (!req)
708 return -ENOMEM;
709
710 ret = dev_pm_qos_add_request(dev, req, DEV_PM_QOS_RESUME_LATENCY, value);
711 if (ret < 0) {
712 kfree(req);
713 return ret;
714 }
715
716 mutex_lock(&dev_pm_qos_sysfs_mtx);
717
718 mutex_lock(&dev_pm_qos_mtx);
719
720 if (IS_ERR_OR_NULL(dev->power.qos))
721 ret = -ENODEV;
722 else if (dev->power.qos->resume_latency_req)
723 ret = -EEXIST;
724
725 if (ret < 0) {
726 __dev_pm_qos_remove_request(req);
727 kfree(req);
728 mutex_unlock(&dev_pm_qos_mtx);
729 goto out;
730 }
731 dev->power.qos->resume_latency_req = req;
732
733 mutex_unlock(&dev_pm_qos_mtx);
734
735 ret = pm_qos_sysfs_add_resume_latency(dev);
736 if (ret)
737 dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_RESUME_LATENCY);
738
739 out:
740 mutex_unlock(&dev_pm_qos_sysfs_mtx);
741 return ret;
742}
743EXPORT_SYMBOL_GPL(dev_pm_qos_expose_latency_limit);
744
745static void __dev_pm_qos_hide_latency_limit(struct device *dev)
746{
747 if (!IS_ERR_OR_NULL(dev->power.qos) && dev->power.qos->resume_latency_req)
748 __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_RESUME_LATENCY);
749}
750
751/**
752 * dev_pm_qos_hide_latency_limit - Hide PM QoS latency limit from user space.
753 * @dev: Device whose PM QoS latency limit is to be hidden from user space.
754 */
755void dev_pm_qos_hide_latency_limit(struct device *dev)
756{
757 mutex_lock(&dev_pm_qos_sysfs_mtx);
758
759 pm_qos_sysfs_remove_resume_latency(dev);
760
761 mutex_lock(&dev_pm_qos_mtx);
762 __dev_pm_qos_hide_latency_limit(dev);
763 mutex_unlock(&dev_pm_qos_mtx);
764
765 mutex_unlock(&dev_pm_qos_sysfs_mtx);
766}
767EXPORT_SYMBOL_GPL(dev_pm_qos_hide_latency_limit);
768
769/**
770 * dev_pm_qos_expose_flags - Expose PM QoS flags of a device to user space.
771 * @dev: Device whose PM QoS flags are to be exposed to user space.
772 * @val: Initial values of the flags.
773 */
774int dev_pm_qos_expose_flags(struct device *dev, s32 val)
775{
776 struct dev_pm_qos_request *req;
777 int ret;
778
779 if (!device_is_registered(dev))
780 return -EINVAL;
781
782 req = kzalloc(sizeof(*req), GFP_KERNEL);
783 if (!req)
784 return -ENOMEM;
785
786 ret = dev_pm_qos_add_request(dev, req, DEV_PM_QOS_FLAGS, val);
787 if (ret < 0) {
788 kfree(req);
789 return ret;
790 }
791
792 pm_runtime_get_sync(dev);
793 mutex_lock(&dev_pm_qos_sysfs_mtx);
794
795 mutex_lock(&dev_pm_qos_mtx);
796
797 if (IS_ERR_OR_NULL(dev->power.qos))
798 ret = -ENODEV;
799 else if (dev->power.qos->flags_req)
800 ret = -EEXIST;
801
802 if (ret < 0) {
803 __dev_pm_qos_remove_request(req);
804 kfree(req);
805 mutex_unlock(&dev_pm_qos_mtx);
806 goto out;
807 }
808 dev->power.qos->flags_req = req;
809
810 mutex_unlock(&dev_pm_qos_mtx);
811
812 ret = pm_qos_sysfs_add_flags(dev);
813 if (ret)
814 dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_FLAGS);
815
816 out:
817 mutex_unlock(&dev_pm_qos_sysfs_mtx);
818 pm_runtime_put(dev);
819 return ret;
820}
821EXPORT_SYMBOL_GPL(dev_pm_qos_expose_flags);
822
823static void __dev_pm_qos_hide_flags(struct device *dev)
824{
825 if (!IS_ERR_OR_NULL(dev->power.qos) && dev->power.qos->flags_req)
826 __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_FLAGS);
827}
828
829/**
830 * dev_pm_qos_hide_flags - Hide PM QoS flags of a device from user space.
831 * @dev: Device whose PM QoS flags are to be hidden from user space.
832 */
833void dev_pm_qos_hide_flags(struct device *dev)
834{
835 pm_runtime_get_sync(dev);
836 mutex_lock(&dev_pm_qos_sysfs_mtx);
837
838 pm_qos_sysfs_remove_flags(dev);
839
840 mutex_lock(&dev_pm_qos_mtx);
841 __dev_pm_qos_hide_flags(dev);
842 mutex_unlock(&dev_pm_qos_mtx);
843
844 mutex_unlock(&dev_pm_qos_sysfs_mtx);
845 pm_runtime_put(dev);
846}
847EXPORT_SYMBOL_GPL(dev_pm_qos_hide_flags);
848
849/**
850 * dev_pm_qos_update_flags - Update PM QoS flags request owned by user space.
851 * @dev: Device to update the PM QoS flags request for.
852 * @mask: Flags to set/clear.
853 * @set: Whether to set or clear the flags (true means set).
854 */
855int dev_pm_qos_update_flags(struct device *dev, s32 mask, bool set)
856{
857 s32 value;
858 int ret;
859
860 pm_runtime_get_sync(dev);
861 mutex_lock(&dev_pm_qos_mtx);
862
863 if (IS_ERR_OR_NULL(dev->power.qos) || !dev->power.qos->flags_req) {
864 ret = -EINVAL;
865 goto out;
866 }
867
868 value = dev_pm_qos_requested_flags(dev);
869 if (set)
870 value |= mask;
871 else
872 value &= ~mask;
873
874 ret = __dev_pm_qos_update_request(dev->power.qos->flags_req, value);
875
876 out:
877 mutex_unlock(&dev_pm_qos_mtx);
878 pm_runtime_put(dev);
879 return ret;
880}
881
882/**
883 * dev_pm_qos_get_user_latency_tolerance - Get user space latency tolerance.
884 * @dev: Device to obtain the user space latency tolerance for.
885 */
886s32 dev_pm_qos_get_user_latency_tolerance(struct device *dev)
887{
888 s32 ret;
889
890 mutex_lock(&dev_pm_qos_mtx);
891 ret = IS_ERR_OR_NULL(dev->power.qos)
892 || !dev->power.qos->latency_tolerance_req ?
893 PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT :
894 dev->power.qos->latency_tolerance_req->data.pnode.prio;
895 mutex_unlock(&dev_pm_qos_mtx);
896 return ret;
897}
898
899/**
900 * dev_pm_qos_update_user_latency_tolerance - Update user space latency tolerance.
901 * @dev: Device to update the user space latency tolerance for.
902 * @val: New user space latency tolerance for @dev (negative values disable).
903 */
904int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
905{
906 int ret;
907
908 mutex_lock(&dev_pm_qos_mtx);
909
910 if (IS_ERR_OR_NULL(dev->power.qos)
911 || !dev->power.qos->latency_tolerance_req) {
912 struct dev_pm_qos_request *req;
913
914 if (val < 0) {
915 if (val == PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT)
916 ret = 0;
917 else
918 ret = -EINVAL;
919 goto out;
920 }
921 req = kzalloc(sizeof(*req), GFP_KERNEL);
922 if (!req) {
923 ret = -ENOMEM;
924 goto out;
925 }
926 ret = __dev_pm_qos_add_request(dev, req, DEV_PM_QOS_LATENCY_TOLERANCE, val);
927 if (ret < 0) {
928 kfree(req);
929 goto out;
930 }
931 dev->power.qos->latency_tolerance_req = req;
932 } else {
933 if (val < 0) {
934 __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_LATENCY_TOLERANCE);
935 ret = 0;
936 } else {
937 ret = __dev_pm_qos_update_request(dev->power.qos->latency_tolerance_req, val);
938 }
939 }
940
941 out:
942 mutex_unlock(&dev_pm_qos_mtx);
943 return ret;
944}
945EXPORT_SYMBOL_GPL(dev_pm_qos_update_user_latency_tolerance);
946
947/**
948 * dev_pm_qos_expose_latency_tolerance - Expose latency tolerance to userspace
949 * @dev: Device whose latency tolerance to expose
950 */
951int dev_pm_qos_expose_latency_tolerance(struct device *dev)
952{
953 int ret;
954
955 if (!dev->power.set_latency_tolerance)
956 return -EINVAL;
957
958 mutex_lock(&dev_pm_qos_sysfs_mtx);
959 ret = pm_qos_sysfs_add_latency_tolerance(dev);
960 mutex_unlock(&dev_pm_qos_sysfs_mtx);
961
962 return ret;
963}
964EXPORT_SYMBOL_GPL(dev_pm_qos_expose_latency_tolerance);
965
966/**
967 * dev_pm_qos_hide_latency_tolerance - Hide latency tolerance from userspace
968 * @dev: Device whose latency tolerance to hide
969 */
970void dev_pm_qos_hide_latency_tolerance(struct device *dev)
971{
972 mutex_lock(&dev_pm_qos_sysfs_mtx);
973 pm_qos_sysfs_remove_latency_tolerance(dev);
974 mutex_unlock(&dev_pm_qos_sysfs_mtx);
975
976 /* Remove the request from user space now */
977 pm_runtime_get_sync(dev);
978 dev_pm_qos_update_user_latency_tolerance(dev,
979 PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT);
980 pm_runtime_put(dev);
981}
982EXPORT_SYMBOL_GPL(dev_pm_qos_hide_latency_tolerance);
1/*
2 * Devices PM QoS constraints management
3 *
4 * Copyright (C) 2011 Texas Instruments, Inc.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 *
11 * This module exposes the interface to kernel space for specifying
12 * per-device PM QoS dependencies. It provides infrastructure for registration
13 * of:
14 *
15 * Dependents on a QoS value : register requests
16 * Watchers of QoS value : get notified when target QoS value changes
17 *
18 * This QoS design is best effort based. Dependents register their QoS needs.
19 * Watchers register to keep track of the current QoS needs of the system.
20 * Watchers can register different types of notification callbacks:
21 * . a per-device notification callback using the dev_pm_qos_*_notifier API.
22 * The notification chain data is stored in the per-device constraint
23 * data struct.
24 * . a system-wide notification callback using the dev_pm_qos_*_global_notifier
25 * API. The notification chain data is stored in a static variable.
26 *
27 * Note about the per-device constraint data struct allocation:
28 * . The per-device constraints data struct ptr is tored into the device
29 * dev_pm_info.
30 * . To minimize the data usage by the per-device constraints, the data struct
31 * is only allocated at the first call to dev_pm_qos_add_request.
32 * . The data is later free'd when the device is removed from the system.
33 * . A global mutex protects the constraints users from the data being
34 * allocated and free'd.
35 */
36
37#include <linux/pm_qos.h>
38#include <linux/spinlock.h>
39#include <linux/slab.h>
40#include <linux/device.h>
41#include <linux/mutex.h>
42#include <linux/export.h>
43#include <linux/pm_runtime.h>
44#include <linux/err.h>
45#include <trace/events/power.h>
46
47#include "power.h"
48
49static DEFINE_MUTEX(dev_pm_qos_mtx);
50static DEFINE_MUTEX(dev_pm_qos_sysfs_mtx);
51
52static BLOCKING_NOTIFIER_HEAD(dev_pm_notifiers);
53
54/**
55 * __dev_pm_qos_flags - Check PM QoS flags for a given device.
56 * @dev: Device to check the PM QoS flags for.
57 * @mask: Flags to check against.
58 *
59 * This routine must be called with dev->power.lock held.
60 */
61enum pm_qos_flags_status __dev_pm_qos_flags(struct device *dev, s32 mask)
62{
63 struct dev_pm_qos *qos = dev->power.qos;
64 struct pm_qos_flags *pqf;
65 s32 val;
66
67 lockdep_assert_held(&dev->power.lock);
68
69 if (IS_ERR_OR_NULL(qos))
70 return PM_QOS_FLAGS_UNDEFINED;
71
72 pqf = &qos->flags;
73 if (list_empty(&pqf->list))
74 return PM_QOS_FLAGS_UNDEFINED;
75
76 val = pqf->effective_flags & mask;
77 if (val)
78 return (val == mask) ? PM_QOS_FLAGS_ALL : PM_QOS_FLAGS_SOME;
79
80 return PM_QOS_FLAGS_NONE;
81}
82
83/**
84 * dev_pm_qos_flags - Check PM QoS flags for a given device (locked).
85 * @dev: Device to check the PM QoS flags for.
86 * @mask: Flags to check against.
87 */
88enum pm_qos_flags_status dev_pm_qos_flags(struct device *dev, s32 mask)
89{
90 unsigned long irqflags;
91 enum pm_qos_flags_status ret;
92
93 spin_lock_irqsave(&dev->power.lock, irqflags);
94 ret = __dev_pm_qos_flags(dev, mask);
95 spin_unlock_irqrestore(&dev->power.lock, irqflags);
96
97 return ret;
98}
99EXPORT_SYMBOL_GPL(dev_pm_qos_flags);
100
101/**
102 * __dev_pm_qos_read_value - Get PM QoS constraint for a given device.
103 * @dev: Device to get the PM QoS constraint value for.
104 *
105 * This routine must be called with dev->power.lock held.
106 */
107s32 __dev_pm_qos_read_value(struct device *dev)
108{
109 lockdep_assert_held(&dev->power.lock);
110
111 return IS_ERR_OR_NULL(dev->power.qos) ?
112 0 : pm_qos_read_value(&dev->power.qos->resume_latency);
113}
114
115/**
116 * dev_pm_qos_read_value - Get PM QoS constraint for a given device (locked).
117 * @dev: Device to get the PM QoS constraint value for.
118 */
119s32 dev_pm_qos_read_value(struct device *dev)
120{
121 unsigned long flags;
122 s32 ret;
123
124 spin_lock_irqsave(&dev->power.lock, flags);
125 ret = __dev_pm_qos_read_value(dev);
126 spin_unlock_irqrestore(&dev->power.lock, flags);
127
128 return ret;
129}
130
131/**
132 * apply_constraint - Add/modify/remove device PM QoS request.
133 * @req: Constraint request to apply
134 * @action: Action to perform (add/update/remove).
135 * @value: Value to assign to the QoS request.
136 *
137 * Internal function to update the constraints list using the PM QoS core
138 * code and if needed call the per-device and the global notification
139 * callbacks
140 */
141static int apply_constraint(struct dev_pm_qos_request *req,
142 enum pm_qos_req_action action, s32 value)
143{
144 struct dev_pm_qos *qos = req->dev->power.qos;
145 int ret;
146
147 switch(req->type) {
148 case DEV_PM_QOS_RESUME_LATENCY:
149 ret = pm_qos_update_target(&qos->resume_latency,
150 &req->data.pnode, action, value);
151 if (ret) {
152 value = pm_qos_read_value(&qos->resume_latency);
153 blocking_notifier_call_chain(&dev_pm_notifiers,
154 (unsigned long)value,
155 req);
156 }
157 break;
158 case DEV_PM_QOS_LATENCY_TOLERANCE:
159 ret = pm_qos_update_target(&qos->latency_tolerance,
160 &req->data.pnode, action, value);
161 if (ret) {
162 value = pm_qos_read_value(&qos->latency_tolerance);
163 req->dev->power.set_latency_tolerance(req->dev, value);
164 }
165 break;
166 case DEV_PM_QOS_FLAGS:
167 ret = pm_qos_update_flags(&qos->flags, &req->data.flr,
168 action, value);
169 break;
170 default:
171 ret = -EINVAL;
172 }
173
174 return ret;
175}
176
177/*
178 * dev_pm_qos_constraints_allocate
179 * @dev: device to allocate data for
180 *
181 * Called at the first call to add_request, for constraint data allocation
182 * Must be called with the dev_pm_qos_mtx mutex held
183 */
184static int dev_pm_qos_constraints_allocate(struct device *dev)
185{
186 struct dev_pm_qos *qos;
187 struct pm_qos_constraints *c;
188 struct blocking_notifier_head *n;
189
190 qos = kzalloc(sizeof(*qos), GFP_KERNEL);
191 if (!qos)
192 return -ENOMEM;
193
194 n = kzalloc(sizeof(*n), GFP_KERNEL);
195 if (!n) {
196 kfree(qos);
197 return -ENOMEM;
198 }
199 BLOCKING_INIT_NOTIFIER_HEAD(n);
200
201 c = &qos->resume_latency;
202 plist_head_init(&c->list);
203 c->target_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;
204 c->default_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;
205 c->no_constraint_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;
206 c->type = PM_QOS_MIN;
207 c->notifiers = n;
208
209 c = &qos->latency_tolerance;
210 plist_head_init(&c->list);
211 c->target_value = PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE;
212 c->default_value = PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE;
213 c->no_constraint_value = PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT;
214 c->type = PM_QOS_MIN;
215
216 INIT_LIST_HEAD(&qos->flags.list);
217
218 spin_lock_irq(&dev->power.lock);
219 dev->power.qos = qos;
220 spin_unlock_irq(&dev->power.lock);
221
222 return 0;
223}
224
225static void __dev_pm_qos_hide_latency_limit(struct device *dev);
226static void __dev_pm_qos_hide_flags(struct device *dev);
227
228/**
229 * dev_pm_qos_constraints_destroy
230 * @dev: target device
231 *
232 * Called from the device PM subsystem on device removal under device_pm_lock().
233 */
234void dev_pm_qos_constraints_destroy(struct device *dev)
235{
236 struct dev_pm_qos *qos;
237 struct dev_pm_qos_request *req, *tmp;
238 struct pm_qos_constraints *c;
239 struct pm_qos_flags *f;
240
241 mutex_lock(&dev_pm_qos_sysfs_mtx);
242
243 /*
244 * If the device's PM QoS resume latency limit or PM QoS flags have been
245 * exposed to user space, they have to be hidden at this point.
246 */
247 pm_qos_sysfs_remove_resume_latency(dev);
248 pm_qos_sysfs_remove_flags(dev);
249
250 mutex_lock(&dev_pm_qos_mtx);
251
252 __dev_pm_qos_hide_latency_limit(dev);
253 __dev_pm_qos_hide_flags(dev);
254
255 qos = dev->power.qos;
256 if (!qos)
257 goto out;
258
259 /* Flush the constraints lists for the device. */
260 c = &qos->resume_latency;
261 plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) {
262 /*
263 * Update constraints list and call the notification
264 * callbacks if needed
265 */
266 apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
267 memset(req, 0, sizeof(*req));
268 }
269 c = &qos->latency_tolerance;
270 plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) {
271 apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
272 memset(req, 0, sizeof(*req));
273 }
274 f = &qos->flags;
275 list_for_each_entry_safe(req, tmp, &f->list, data.flr.node) {
276 apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
277 memset(req, 0, sizeof(*req));
278 }
279
280 spin_lock_irq(&dev->power.lock);
281 dev->power.qos = ERR_PTR(-ENODEV);
282 spin_unlock_irq(&dev->power.lock);
283
284 kfree(c->notifiers);
285 kfree(qos);
286
287 out:
288 mutex_unlock(&dev_pm_qos_mtx);
289
290 mutex_unlock(&dev_pm_qos_sysfs_mtx);
291}
292
293static bool dev_pm_qos_invalid_request(struct device *dev,
294 struct dev_pm_qos_request *req)
295{
296 return !req || (req->type == DEV_PM_QOS_LATENCY_TOLERANCE
297 && !dev->power.set_latency_tolerance);
298}
299
300static int __dev_pm_qos_add_request(struct device *dev,
301 struct dev_pm_qos_request *req,
302 enum dev_pm_qos_req_type type, s32 value)
303{
304 int ret = 0;
305
306 if (!dev || dev_pm_qos_invalid_request(dev, req))
307 return -EINVAL;
308
309 if (WARN(dev_pm_qos_request_active(req),
310 "%s() called for already added request\n", __func__))
311 return -EINVAL;
312
313 if (IS_ERR(dev->power.qos))
314 ret = -ENODEV;
315 else if (!dev->power.qos)
316 ret = dev_pm_qos_constraints_allocate(dev);
317
318 trace_dev_pm_qos_add_request(dev_name(dev), type, value);
319 if (!ret) {
320 req->dev = dev;
321 req->type = type;
322 ret = apply_constraint(req, PM_QOS_ADD_REQ, value);
323 }
324 return ret;
325}
326
327/**
328 * dev_pm_qos_add_request - inserts new qos request into the list
329 * @dev: target device for the constraint
330 * @req: pointer to a preallocated handle
331 * @type: type of the request
332 * @value: defines the qos request
333 *
334 * This function inserts a new entry in the device constraints list of
335 * requested qos performance characteristics. It recomputes the aggregate
336 * QoS expectations of parameters and initializes the dev_pm_qos_request
337 * handle. Caller needs to save this handle for later use in updates and
338 * removal.
339 *
340 * Returns 1 if the aggregated constraint value has changed,
341 * 0 if the aggregated constraint value has not changed,
342 * -EINVAL in case of wrong parameters, -ENOMEM if there's not enough memory
343 * to allocate for data structures, -ENODEV if the device has just been removed
344 * from the system.
345 *
346 * Callers should ensure that the target device is not RPM_SUSPENDED before
347 * using this function for requests of type DEV_PM_QOS_FLAGS.
348 */
349int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
350 enum dev_pm_qos_req_type type, s32 value)
351{
352 int ret;
353
354 mutex_lock(&dev_pm_qos_mtx);
355 ret = __dev_pm_qos_add_request(dev, req, type, value);
356 mutex_unlock(&dev_pm_qos_mtx);
357 return ret;
358}
359EXPORT_SYMBOL_GPL(dev_pm_qos_add_request);
360
361/**
362 * __dev_pm_qos_update_request - Modify an existing device PM QoS request.
363 * @req : PM QoS request to modify.
364 * @new_value: New value to request.
365 */
366static int __dev_pm_qos_update_request(struct dev_pm_qos_request *req,
367 s32 new_value)
368{
369 s32 curr_value;
370 int ret = 0;
371
372 if (!req) /*guard against callers passing in null */
373 return -EINVAL;
374
375 if (WARN(!dev_pm_qos_request_active(req),
376 "%s() called for unknown object\n", __func__))
377 return -EINVAL;
378
379 if (IS_ERR_OR_NULL(req->dev->power.qos))
380 return -ENODEV;
381
382 switch(req->type) {
383 case DEV_PM_QOS_RESUME_LATENCY:
384 case DEV_PM_QOS_LATENCY_TOLERANCE:
385 curr_value = req->data.pnode.prio;
386 break;
387 case DEV_PM_QOS_FLAGS:
388 curr_value = req->data.flr.flags;
389 break;
390 default:
391 return -EINVAL;
392 }
393
394 trace_dev_pm_qos_update_request(dev_name(req->dev), req->type,
395 new_value);
396 if (curr_value != new_value)
397 ret = apply_constraint(req, PM_QOS_UPDATE_REQ, new_value);
398
399 return ret;
400}
401
402/**
403 * dev_pm_qos_update_request - modifies an existing qos request
404 * @req : handle to list element holding a dev_pm_qos request to use
405 * @new_value: defines the qos request
406 *
407 * Updates an existing dev PM qos request along with updating the
408 * target value.
409 *
410 * Attempts are made to make this code callable on hot code paths.
411 *
412 * Returns 1 if the aggregated constraint value has changed,
413 * 0 if the aggregated constraint value has not changed,
414 * -EINVAL in case of wrong parameters, -ENODEV if the device has been
415 * removed from the system
416 *
417 * Callers should ensure that the target device is not RPM_SUSPENDED before
418 * using this function for requests of type DEV_PM_QOS_FLAGS.
419 */
420int dev_pm_qos_update_request(struct dev_pm_qos_request *req, s32 new_value)
421{
422 int ret;
423
424 mutex_lock(&dev_pm_qos_mtx);
425 ret = __dev_pm_qos_update_request(req, new_value);
426 mutex_unlock(&dev_pm_qos_mtx);
427 return ret;
428}
429EXPORT_SYMBOL_GPL(dev_pm_qos_update_request);
430
431static int __dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
432{
433 int ret;
434
435 if (!req) /*guard against callers passing in null */
436 return -EINVAL;
437
438 if (WARN(!dev_pm_qos_request_active(req),
439 "%s() called for unknown object\n", __func__))
440 return -EINVAL;
441
442 if (IS_ERR_OR_NULL(req->dev->power.qos))
443 return -ENODEV;
444
445 trace_dev_pm_qos_remove_request(dev_name(req->dev), req->type,
446 PM_QOS_DEFAULT_VALUE);
447 ret = apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
448 memset(req, 0, sizeof(*req));
449 return ret;
450}
451
452/**
453 * dev_pm_qos_remove_request - modifies an existing qos request
454 * @req: handle to request list element
455 *
456 * Will remove pm qos request from the list of constraints and
457 * recompute the current target value. Call this on slow code paths.
458 *
459 * Returns 1 if the aggregated constraint value has changed,
460 * 0 if the aggregated constraint value has not changed,
461 * -EINVAL in case of wrong parameters, -ENODEV if the device has been
462 * removed from the system
463 *
464 * Callers should ensure that the target device is not RPM_SUSPENDED before
465 * using this function for requests of type DEV_PM_QOS_FLAGS.
466 */
467int dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
468{
469 int ret;
470
471 mutex_lock(&dev_pm_qos_mtx);
472 ret = __dev_pm_qos_remove_request(req);
473 mutex_unlock(&dev_pm_qos_mtx);
474 return ret;
475}
476EXPORT_SYMBOL_GPL(dev_pm_qos_remove_request);
477
478/**
479 * dev_pm_qos_add_notifier - sets notification entry for changes to target value
480 * of per-device PM QoS constraints
481 *
482 * @dev: target device for the constraint
483 * @notifier: notifier block managed by caller.
484 *
485 * Will register the notifier into a notification chain that gets called
486 * upon changes to the target value for the device.
487 *
488 * If the device's constraints object doesn't exist when this routine is called,
489 * it will be created (or error code will be returned if that fails).
490 */
491int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier)
492{
493 int ret = 0;
494
495 mutex_lock(&dev_pm_qos_mtx);
496
497 if (IS_ERR(dev->power.qos))
498 ret = -ENODEV;
499 else if (!dev->power.qos)
500 ret = dev_pm_qos_constraints_allocate(dev);
501
502 if (!ret)
503 ret = blocking_notifier_chain_register(dev->power.qos->resume_latency.notifiers,
504 notifier);
505
506 mutex_unlock(&dev_pm_qos_mtx);
507 return ret;
508}
509EXPORT_SYMBOL_GPL(dev_pm_qos_add_notifier);
510
511/**
512 * dev_pm_qos_remove_notifier - deletes notification for changes to target value
513 * of per-device PM QoS constraints
514 *
515 * @dev: target device for the constraint
516 * @notifier: notifier block to be removed.
517 *
518 * Will remove the notifier from the notification chain that gets called
519 * upon changes to the target value.
520 */
521int dev_pm_qos_remove_notifier(struct device *dev,
522 struct notifier_block *notifier)
523{
524 int retval = 0;
525
526 mutex_lock(&dev_pm_qos_mtx);
527
528 /* Silently return if the constraints object is not present. */
529 if (!IS_ERR_OR_NULL(dev->power.qos))
530 retval = blocking_notifier_chain_unregister(dev->power.qos->resume_latency.notifiers,
531 notifier);
532
533 mutex_unlock(&dev_pm_qos_mtx);
534 return retval;
535}
536EXPORT_SYMBOL_GPL(dev_pm_qos_remove_notifier);
537
538/**
539 * dev_pm_qos_add_global_notifier - sets notification entry for changes to
540 * target value of the PM QoS constraints for any device
541 *
542 * @notifier: notifier block managed by caller.
543 *
544 * Will register the notifier into a notification chain that gets called
545 * upon changes to the target value for any device.
546 */
547int dev_pm_qos_add_global_notifier(struct notifier_block *notifier)
548{
549 return blocking_notifier_chain_register(&dev_pm_notifiers, notifier);
550}
551EXPORT_SYMBOL_GPL(dev_pm_qos_add_global_notifier);
552
553/**
554 * dev_pm_qos_remove_global_notifier - deletes notification for changes to
555 * target value of PM QoS constraints for any device
556 *
557 * @notifier: notifier block to be removed.
558 *
559 * Will remove the notifier from the notification chain that gets called
560 * upon changes to the target value for any device.
561 */
562int dev_pm_qos_remove_global_notifier(struct notifier_block *notifier)
563{
564 return blocking_notifier_chain_unregister(&dev_pm_notifiers, notifier);
565}
566EXPORT_SYMBOL_GPL(dev_pm_qos_remove_global_notifier);
567
568/**
569 * dev_pm_qos_add_ancestor_request - Add PM QoS request for device's ancestor.
570 * @dev: Device whose ancestor to add the request for.
571 * @req: Pointer to the preallocated handle.
572 * @type: Type of the request.
573 * @value: Constraint latency value.
574 */
575int dev_pm_qos_add_ancestor_request(struct device *dev,
576 struct dev_pm_qos_request *req,
577 enum dev_pm_qos_req_type type, s32 value)
578{
579 struct device *ancestor = dev->parent;
580 int ret = -ENODEV;
581
582 switch (type) {
583 case DEV_PM_QOS_RESUME_LATENCY:
584 while (ancestor && !ancestor->power.ignore_children)
585 ancestor = ancestor->parent;
586
587 break;
588 case DEV_PM_QOS_LATENCY_TOLERANCE:
589 while (ancestor && !ancestor->power.set_latency_tolerance)
590 ancestor = ancestor->parent;
591
592 break;
593 default:
594 ancestor = NULL;
595 }
596 if (ancestor)
597 ret = dev_pm_qos_add_request(ancestor, req, type, value);
598
599 if (ret < 0)
600 req->dev = NULL;
601
602 return ret;
603}
604EXPORT_SYMBOL_GPL(dev_pm_qos_add_ancestor_request);
605
606static void __dev_pm_qos_drop_user_request(struct device *dev,
607 enum dev_pm_qos_req_type type)
608{
609 struct dev_pm_qos_request *req = NULL;
610
611 switch(type) {
612 case DEV_PM_QOS_RESUME_LATENCY:
613 req = dev->power.qos->resume_latency_req;
614 dev->power.qos->resume_latency_req = NULL;
615 break;
616 case DEV_PM_QOS_LATENCY_TOLERANCE:
617 req = dev->power.qos->latency_tolerance_req;
618 dev->power.qos->latency_tolerance_req = NULL;
619 break;
620 case DEV_PM_QOS_FLAGS:
621 req = dev->power.qos->flags_req;
622 dev->power.qos->flags_req = NULL;
623 break;
624 }
625 __dev_pm_qos_remove_request(req);
626 kfree(req);
627}
628
629static void dev_pm_qos_drop_user_request(struct device *dev,
630 enum dev_pm_qos_req_type type)
631{
632 mutex_lock(&dev_pm_qos_mtx);
633 __dev_pm_qos_drop_user_request(dev, type);
634 mutex_unlock(&dev_pm_qos_mtx);
635}
636
637/**
638 * dev_pm_qos_expose_latency_limit - Expose PM QoS latency limit to user space.
639 * @dev: Device whose PM QoS latency limit is to be exposed to user space.
640 * @value: Initial value of the latency limit.
641 */
642int dev_pm_qos_expose_latency_limit(struct device *dev, s32 value)
643{
644 struct dev_pm_qos_request *req;
645 int ret;
646
647 if (!device_is_registered(dev) || value < 0)
648 return -EINVAL;
649
650 req = kzalloc(sizeof(*req), GFP_KERNEL);
651 if (!req)
652 return -ENOMEM;
653
654 ret = dev_pm_qos_add_request(dev, req, DEV_PM_QOS_RESUME_LATENCY, value);
655 if (ret < 0) {
656 kfree(req);
657 return ret;
658 }
659
660 mutex_lock(&dev_pm_qos_sysfs_mtx);
661
662 mutex_lock(&dev_pm_qos_mtx);
663
664 if (IS_ERR_OR_NULL(dev->power.qos))
665 ret = -ENODEV;
666 else if (dev->power.qos->resume_latency_req)
667 ret = -EEXIST;
668
669 if (ret < 0) {
670 __dev_pm_qos_remove_request(req);
671 kfree(req);
672 mutex_unlock(&dev_pm_qos_mtx);
673 goto out;
674 }
675 dev->power.qos->resume_latency_req = req;
676
677 mutex_unlock(&dev_pm_qos_mtx);
678
679 ret = pm_qos_sysfs_add_resume_latency(dev);
680 if (ret)
681 dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_RESUME_LATENCY);
682
683 out:
684 mutex_unlock(&dev_pm_qos_sysfs_mtx);
685 return ret;
686}
687EXPORT_SYMBOL_GPL(dev_pm_qos_expose_latency_limit);
688
689static void __dev_pm_qos_hide_latency_limit(struct device *dev)
690{
691 if (!IS_ERR_OR_NULL(dev->power.qos) && dev->power.qos->resume_latency_req)
692 __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_RESUME_LATENCY);
693}
694
695/**
696 * dev_pm_qos_hide_latency_limit - Hide PM QoS latency limit from user space.
697 * @dev: Device whose PM QoS latency limit is to be hidden from user space.
698 */
699void dev_pm_qos_hide_latency_limit(struct device *dev)
700{
701 mutex_lock(&dev_pm_qos_sysfs_mtx);
702
703 pm_qos_sysfs_remove_resume_latency(dev);
704
705 mutex_lock(&dev_pm_qos_mtx);
706 __dev_pm_qos_hide_latency_limit(dev);
707 mutex_unlock(&dev_pm_qos_mtx);
708
709 mutex_unlock(&dev_pm_qos_sysfs_mtx);
710}
711EXPORT_SYMBOL_GPL(dev_pm_qos_hide_latency_limit);
712
713/**
714 * dev_pm_qos_expose_flags - Expose PM QoS flags of a device to user space.
715 * @dev: Device whose PM QoS flags are to be exposed to user space.
716 * @val: Initial values of the flags.
717 */
718int dev_pm_qos_expose_flags(struct device *dev, s32 val)
719{
720 struct dev_pm_qos_request *req;
721 int ret;
722
723 if (!device_is_registered(dev))
724 return -EINVAL;
725
726 req = kzalloc(sizeof(*req), GFP_KERNEL);
727 if (!req)
728 return -ENOMEM;
729
730 ret = dev_pm_qos_add_request(dev, req, DEV_PM_QOS_FLAGS, val);
731 if (ret < 0) {
732 kfree(req);
733 return ret;
734 }
735
736 pm_runtime_get_sync(dev);
737 mutex_lock(&dev_pm_qos_sysfs_mtx);
738
739 mutex_lock(&dev_pm_qos_mtx);
740
741 if (IS_ERR_OR_NULL(dev->power.qos))
742 ret = -ENODEV;
743 else if (dev->power.qos->flags_req)
744 ret = -EEXIST;
745
746 if (ret < 0) {
747 __dev_pm_qos_remove_request(req);
748 kfree(req);
749 mutex_unlock(&dev_pm_qos_mtx);
750 goto out;
751 }
752 dev->power.qos->flags_req = req;
753
754 mutex_unlock(&dev_pm_qos_mtx);
755
756 ret = pm_qos_sysfs_add_flags(dev);
757 if (ret)
758 dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_FLAGS);
759
760 out:
761 mutex_unlock(&dev_pm_qos_sysfs_mtx);
762 pm_runtime_put(dev);
763 return ret;
764}
765EXPORT_SYMBOL_GPL(dev_pm_qos_expose_flags);
766
767static void __dev_pm_qos_hide_flags(struct device *dev)
768{
769 if (!IS_ERR_OR_NULL(dev->power.qos) && dev->power.qos->flags_req)
770 __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_FLAGS);
771}
772
773/**
774 * dev_pm_qos_hide_flags - Hide PM QoS flags of a device from user space.
775 * @dev: Device whose PM QoS flags are to be hidden from user space.
776 */
777void dev_pm_qos_hide_flags(struct device *dev)
778{
779 pm_runtime_get_sync(dev);
780 mutex_lock(&dev_pm_qos_sysfs_mtx);
781
782 pm_qos_sysfs_remove_flags(dev);
783
784 mutex_lock(&dev_pm_qos_mtx);
785 __dev_pm_qos_hide_flags(dev);
786 mutex_unlock(&dev_pm_qos_mtx);
787
788 mutex_unlock(&dev_pm_qos_sysfs_mtx);
789 pm_runtime_put(dev);
790}
791EXPORT_SYMBOL_GPL(dev_pm_qos_hide_flags);
792
793/**
794 * dev_pm_qos_update_flags - Update PM QoS flags request owned by user space.
795 * @dev: Device to update the PM QoS flags request for.
796 * @mask: Flags to set/clear.
797 * @set: Whether to set or clear the flags (true means set).
798 */
799int dev_pm_qos_update_flags(struct device *dev, s32 mask, bool set)
800{
801 s32 value;
802 int ret;
803
804 pm_runtime_get_sync(dev);
805 mutex_lock(&dev_pm_qos_mtx);
806
807 if (IS_ERR_OR_NULL(dev->power.qos) || !dev->power.qos->flags_req) {
808 ret = -EINVAL;
809 goto out;
810 }
811
812 value = dev_pm_qos_requested_flags(dev);
813 if (set)
814 value |= mask;
815 else
816 value &= ~mask;
817
818 ret = __dev_pm_qos_update_request(dev->power.qos->flags_req, value);
819
820 out:
821 mutex_unlock(&dev_pm_qos_mtx);
822 pm_runtime_put(dev);
823 return ret;
824}
825
826/**
827 * dev_pm_qos_get_user_latency_tolerance - Get user space latency tolerance.
828 * @dev: Device to obtain the user space latency tolerance for.
829 */
830s32 dev_pm_qos_get_user_latency_tolerance(struct device *dev)
831{
832 s32 ret;
833
834 mutex_lock(&dev_pm_qos_mtx);
835 ret = IS_ERR_OR_NULL(dev->power.qos)
836 || !dev->power.qos->latency_tolerance_req ?
837 PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT :
838 dev->power.qos->latency_tolerance_req->data.pnode.prio;
839 mutex_unlock(&dev_pm_qos_mtx);
840 return ret;
841}
842
843/**
844 * dev_pm_qos_update_user_latency_tolerance - Update user space latency tolerance.
845 * @dev: Device to update the user space latency tolerance for.
846 * @val: New user space latency tolerance for @dev (negative values disable).
847 */
848int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
849{
850 int ret;
851
852 mutex_lock(&dev_pm_qos_mtx);
853
854 if (IS_ERR_OR_NULL(dev->power.qos)
855 || !dev->power.qos->latency_tolerance_req) {
856 struct dev_pm_qos_request *req;
857
858 if (val < 0) {
859 if (val == PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT)
860 ret = 0;
861 else
862 ret = -EINVAL;
863 goto out;
864 }
865 req = kzalloc(sizeof(*req), GFP_KERNEL);
866 if (!req) {
867 ret = -ENOMEM;
868 goto out;
869 }
870 ret = __dev_pm_qos_add_request(dev, req, DEV_PM_QOS_LATENCY_TOLERANCE, val);
871 if (ret < 0) {
872 kfree(req);
873 goto out;
874 }
875 dev->power.qos->latency_tolerance_req = req;
876 } else {
877 if (val < 0) {
878 __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_LATENCY_TOLERANCE);
879 ret = 0;
880 } else {
881 ret = __dev_pm_qos_update_request(dev->power.qos->latency_tolerance_req, val);
882 }
883 }
884
885 out:
886 mutex_unlock(&dev_pm_qos_mtx);
887 return ret;
888}
889EXPORT_SYMBOL_GPL(dev_pm_qos_update_user_latency_tolerance);
890
891/**
892 * dev_pm_qos_expose_latency_tolerance - Expose latency tolerance to userspace
893 * @dev: Device whose latency tolerance to expose
894 */
895int dev_pm_qos_expose_latency_tolerance(struct device *dev)
896{
897 int ret;
898
899 if (!dev->power.set_latency_tolerance)
900 return -EINVAL;
901
902 mutex_lock(&dev_pm_qos_sysfs_mtx);
903 ret = pm_qos_sysfs_add_latency_tolerance(dev);
904 mutex_unlock(&dev_pm_qos_sysfs_mtx);
905
906 return ret;
907}
908EXPORT_SYMBOL_GPL(dev_pm_qos_expose_latency_tolerance);
909
910/**
911 * dev_pm_qos_hide_latency_tolerance - Hide latency tolerance from userspace
912 * @dev: Device whose latency tolerance to hide
913 */
914void dev_pm_qos_hide_latency_tolerance(struct device *dev)
915{
916 mutex_lock(&dev_pm_qos_sysfs_mtx);
917 pm_qos_sysfs_remove_latency_tolerance(dev);
918 mutex_unlock(&dev_pm_qos_sysfs_mtx);
919
920 /* Remove the request from user space now */
921 pm_runtime_get_sync(dev);
922 dev_pm_qos_update_user_latency_tolerance(dev,
923 PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT);
924 pm_runtime_put(dev);
925}
926EXPORT_SYMBOL_GPL(dev_pm_qos_hide_latency_tolerance);