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