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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 = kzalloc(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// 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}
140EXPORT_SYMBOL_GPL(dev_pm_qos_read_value);
141
142/**
143 * apply_constraint - Add/modify/remove device PM QoS request.
144 * @req: Constraint request to apply
145 * @action: Action to perform (add/update/remove).
146 * @value: Value to assign to the QoS request.
147 *
148 * Internal function to update the constraints list using the PM QoS core
149 * code and if needed call the per-device callbacks.
150 */
151static int apply_constraint(struct dev_pm_qos_request *req,
152 enum pm_qos_req_action action, s32 value)
153{
154 struct dev_pm_qos *qos = req->dev->power.qos;
155 int ret;
156
157 switch(req->type) {
158 case DEV_PM_QOS_RESUME_LATENCY:
159 if (WARN_ON(action != PM_QOS_REMOVE_REQ && value < 0))
160 value = 0;
161
162 ret = pm_qos_update_target(&qos->resume_latency,
163 &req->data.pnode, action, value);
164 break;
165 case DEV_PM_QOS_LATENCY_TOLERANCE:
166 ret = pm_qos_update_target(&qos->latency_tolerance,
167 &req->data.pnode, action, value);
168 if (ret) {
169 value = pm_qos_read_value(&qos->latency_tolerance);
170 req->dev->power.set_latency_tolerance(req->dev, value);
171 }
172 break;
173 case DEV_PM_QOS_MIN_FREQUENCY:
174 case DEV_PM_QOS_MAX_FREQUENCY:
175 ret = freq_qos_apply(&req->data.freq, action, value);
176 break;
177 case DEV_PM_QOS_FLAGS:
178 ret = pm_qos_update_flags(&qos->flags, &req->data.flr,
179 action, value);
180 break;
181 default:
182 ret = -EINVAL;
183 }
184
185 return ret;
186}
187
188/*
189 * dev_pm_qos_constraints_allocate
190 * @dev: device to allocate data for
191 *
192 * Called at the first call to add_request, for constraint data allocation
193 * Must be called with the dev_pm_qos_mtx mutex held
194 */
195static int dev_pm_qos_constraints_allocate(struct device *dev)
196{
197 struct dev_pm_qos *qos;
198 struct pm_qos_constraints *c;
199 struct blocking_notifier_head *n;
200
201 qos = kzalloc(sizeof(*qos), GFP_KERNEL);
202 if (!qos)
203 return -ENOMEM;
204
205 n = kcalloc(3, sizeof(*n), GFP_KERNEL);
206 if (!n) {
207 kfree(qos);
208 return -ENOMEM;
209 }
210
211 c = &qos->resume_latency;
212 plist_head_init(&c->list);
213 c->target_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;
214 c->default_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;
215 c->no_constraint_value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT;
216 c->type = PM_QOS_MIN;
217 c->notifiers = n;
218 BLOCKING_INIT_NOTIFIER_HEAD(n);
219
220 c = &qos->latency_tolerance;
221 plist_head_init(&c->list);
222 c->target_value = PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE;
223 c->default_value = PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE;
224 c->no_constraint_value = PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT;
225 c->type = PM_QOS_MIN;
226
227 freq_constraints_init(&qos->freq);
228
229 INIT_LIST_HEAD(&qos->flags.list);
230
231 spin_lock_irq(&dev->power.lock);
232 dev->power.qos = qos;
233 spin_unlock_irq(&dev->power.lock);
234
235 return 0;
236}
237
238static void __dev_pm_qos_hide_latency_limit(struct device *dev);
239static void __dev_pm_qos_hide_flags(struct device *dev);
240
241/**
242 * dev_pm_qos_constraints_destroy
243 * @dev: target device
244 *
245 * Called from the device PM subsystem on device removal under device_pm_lock().
246 */
247void dev_pm_qos_constraints_destroy(struct device *dev)
248{
249 struct dev_pm_qos *qos;
250 struct dev_pm_qos_request *req, *tmp;
251 struct pm_qos_constraints *c;
252 struct pm_qos_flags *f;
253
254 mutex_lock(&dev_pm_qos_sysfs_mtx);
255
256 /*
257 * If the device's PM QoS resume latency limit or PM QoS flags have been
258 * exposed to user space, they have to be hidden at this point.
259 */
260 pm_qos_sysfs_remove_resume_latency(dev);
261 pm_qos_sysfs_remove_flags(dev);
262
263 mutex_lock(&dev_pm_qos_mtx);
264
265 __dev_pm_qos_hide_latency_limit(dev);
266 __dev_pm_qos_hide_flags(dev);
267
268 qos = dev->power.qos;
269 if (!qos)
270 goto out;
271
272 /* Flush the constraints lists for the device. */
273 c = &qos->resume_latency;
274 plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) {
275 /*
276 * Update constraints list and call the notification
277 * callbacks if needed
278 */
279 apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
280 memset(req, 0, sizeof(*req));
281 }
282
283 c = &qos->latency_tolerance;
284 plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) {
285 apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
286 memset(req, 0, sizeof(*req));
287 }
288
289 c = &qos->freq.min_freq;
290 plist_for_each_entry_safe(req, tmp, &c->list, data.freq.pnode) {
291 apply_constraint(req, PM_QOS_REMOVE_REQ,
292 PM_QOS_MIN_FREQUENCY_DEFAULT_VALUE);
293 memset(req, 0, sizeof(*req));
294 }
295
296 c = &qos->freq.max_freq;
297 plist_for_each_entry_safe(req, tmp, &c->list, data.freq.pnode) {
298 apply_constraint(req, PM_QOS_REMOVE_REQ,
299 PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
300 memset(req, 0, sizeof(*req));
301 }
302
303 f = &qos->flags;
304 list_for_each_entry_safe(req, tmp, &f->list, data.flr.node) {
305 apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
306 memset(req, 0, sizeof(*req));
307 }
308
309 spin_lock_irq(&dev->power.lock);
310 dev->power.qos = ERR_PTR(-ENODEV);
311 spin_unlock_irq(&dev->power.lock);
312
313 kfree(qos->resume_latency.notifiers);
314 kfree(qos);
315
316 out:
317 mutex_unlock(&dev_pm_qos_mtx);
318
319 mutex_unlock(&dev_pm_qos_sysfs_mtx);
320}
321
322static bool dev_pm_qos_invalid_req_type(struct device *dev,
323 enum dev_pm_qos_req_type type)
324{
325 return type == DEV_PM_QOS_LATENCY_TOLERANCE &&
326 !dev->power.set_latency_tolerance;
327}
328
329static int __dev_pm_qos_add_request(struct device *dev,
330 struct dev_pm_qos_request *req,
331 enum dev_pm_qos_req_type type, s32 value)
332{
333 int ret = 0;
334
335 if (!dev || !req || dev_pm_qos_invalid_req_type(dev, type))
336 return -EINVAL;
337
338 if (WARN(dev_pm_qos_request_active(req),
339 "%s() called for already added request\n", __func__))
340 return -EINVAL;
341
342 if (IS_ERR(dev->power.qos))
343 ret = -ENODEV;
344 else if (!dev->power.qos)
345 ret = dev_pm_qos_constraints_allocate(dev);
346
347 trace_dev_pm_qos_add_request(dev_name(dev), type, value);
348 if (ret)
349 return ret;
350
351 req->dev = dev;
352 req->type = type;
353 if (req->type == DEV_PM_QOS_MIN_FREQUENCY)
354 ret = freq_qos_add_request(&dev->power.qos->freq,
355 &req->data.freq,
356 FREQ_QOS_MIN, value);
357 else if (req->type == DEV_PM_QOS_MAX_FREQUENCY)
358 ret = freq_qos_add_request(&dev->power.qos->freq,
359 &req->data.freq,
360 FREQ_QOS_MAX, value);
361 else
362 ret = apply_constraint(req, PM_QOS_ADD_REQ, value);
363
364 return ret;
365}
366
367/**
368 * dev_pm_qos_add_request - inserts new qos request into the list
369 * @dev: target device for the constraint
370 * @req: pointer to a preallocated handle
371 * @type: type of the request
372 * @value: defines the qos request
373 *
374 * This function inserts a new entry in the device constraints list of
375 * requested qos performance characteristics. It recomputes the aggregate
376 * QoS expectations of parameters and initializes the dev_pm_qos_request
377 * handle. Caller needs to save this handle for later use in updates and
378 * removal.
379 *
380 * Returns 1 if the aggregated constraint value has changed,
381 * 0 if the aggregated constraint value has not changed,
382 * -EINVAL in case of wrong parameters, -ENOMEM if there's not enough memory
383 * to allocate for data structures, -ENODEV if the device has just been removed
384 * from the system.
385 *
386 * Callers should ensure that the target device is not RPM_SUSPENDED before
387 * using this function for requests of type DEV_PM_QOS_FLAGS.
388 */
389int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
390 enum dev_pm_qos_req_type type, s32 value)
391{
392 int ret;
393
394 mutex_lock(&dev_pm_qos_mtx);
395 ret = __dev_pm_qos_add_request(dev, req, type, value);
396 mutex_unlock(&dev_pm_qos_mtx);
397 return ret;
398}
399EXPORT_SYMBOL_GPL(dev_pm_qos_add_request);
400
401/**
402 * __dev_pm_qos_update_request - Modify an existing device PM QoS request.
403 * @req : PM QoS request to modify.
404 * @new_value: New value to request.
405 */
406static int __dev_pm_qos_update_request(struct dev_pm_qos_request *req,
407 s32 new_value)
408{
409 s32 curr_value;
410 int ret = 0;
411
412 if (!req) /*guard against callers passing in null */
413 return -EINVAL;
414
415 if (WARN(!dev_pm_qos_request_active(req),
416 "%s() called for unknown object\n", __func__))
417 return -EINVAL;
418
419 if (IS_ERR_OR_NULL(req->dev->power.qos))
420 return -ENODEV;
421
422 switch(req->type) {
423 case DEV_PM_QOS_RESUME_LATENCY:
424 case DEV_PM_QOS_LATENCY_TOLERANCE:
425 curr_value = req->data.pnode.prio;
426 break;
427 case DEV_PM_QOS_MIN_FREQUENCY:
428 case DEV_PM_QOS_MAX_FREQUENCY:
429 curr_value = req->data.freq.pnode.prio;
430 break;
431 case DEV_PM_QOS_FLAGS:
432 curr_value = req->data.flr.flags;
433 break;
434 default:
435 return -EINVAL;
436 }
437
438 trace_dev_pm_qos_update_request(dev_name(req->dev), req->type,
439 new_value);
440 if (curr_value != new_value)
441 ret = apply_constraint(req, PM_QOS_UPDATE_REQ, new_value);
442
443 return ret;
444}
445
446/**
447 * dev_pm_qos_update_request - modifies an existing qos request
448 * @req : handle to list element holding a dev_pm_qos request to use
449 * @new_value: defines the qos request
450 *
451 * Updates an existing dev PM qos request along with updating the
452 * target value.
453 *
454 * Attempts are made to make this code callable on hot code paths.
455 *
456 * Returns 1 if the aggregated constraint value has changed,
457 * 0 if the aggregated constraint value has not changed,
458 * -EINVAL in case of wrong parameters, -ENODEV if the device has been
459 * removed from the system
460 *
461 * Callers should ensure that the target device is not RPM_SUSPENDED before
462 * using this function for requests of type DEV_PM_QOS_FLAGS.
463 */
464int dev_pm_qos_update_request(struct dev_pm_qos_request *req, s32 new_value)
465{
466 int ret;
467
468 mutex_lock(&dev_pm_qos_mtx);
469 ret = __dev_pm_qos_update_request(req, new_value);
470 mutex_unlock(&dev_pm_qos_mtx);
471 return ret;
472}
473EXPORT_SYMBOL_GPL(dev_pm_qos_update_request);
474
475static int __dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
476{
477 int ret;
478
479 if (!req) /*guard against callers passing in null */
480 return -EINVAL;
481
482 if (WARN(!dev_pm_qos_request_active(req),
483 "%s() called for unknown object\n", __func__))
484 return -EINVAL;
485
486 if (IS_ERR_OR_NULL(req->dev->power.qos))
487 return -ENODEV;
488
489 trace_dev_pm_qos_remove_request(dev_name(req->dev), req->type,
490 PM_QOS_DEFAULT_VALUE);
491 ret = apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
492 memset(req, 0, sizeof(*req));
493 return ret;
494}
495
496/**
497 * dev_pm_qos_remove_request - modifies an existing qos request
498 * @req: handle to request list element
499 *
500 * Will remove pm qos request from the list of constraints and
501 * recompute the current target value. Call this on slow code paths.
502 *
503 * Returns 1 if the aggregated constraint value has changed,
504 * 0 if the aggregated constraint value has not changed,
505 * -EINVAL in case of wrong parameters, -ENODEV if the device has been
506 * removed from the system
507 *
508 * Callers should ensure that the target device is not RPM_SUSPENDED before
509 * using this function for requests of type DEV_PM_QOS_FLAGS.
510 */
511int dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
512{
513 int ret;
514
515 mutex_lock(&dev_pm_qos_mtx);
516 ret = __dev_pm_qos_remove_request(req);
517 mutex_unlock(&dev_pm_qos_mtx);
518 return ret;
519}
520EXPORT_SYMBOL_GPL(dev_pm_qos_remove_request);
521
522/**
523 * dev_pm_qos_add_notifier - sets notification entry for changes to target value
524 * of per-device PM QoS constraints
525 *
526 * @dev: target device for the constraint
527 * @notifier: notifier block managed by caller.
528 * @type: request type.
529 *
530 * Will register the notifier into a notification chain that gets called
531 * upon changes to the target value for the device.
532 *
533 * If the device's constraints object doesn't exist when this routine is called,
534 * it will be created (or error code will be returned if that fails).
535 */
536int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier,
537 enum dev_pm_qos_req_type type)
538{
539 int ret = 0;
540
541 mutex_lock(&dev_pm_qos_mtx);
542
543 if (IS_ERR(dev->power.qos))
544 ret = -ENODEV;
545 else if (!dev->power.qos)
546 ret = dev_pm_qos_constraints_allocate(dev);
547
548 if (ret)
549 goto unlock;
550
551 switch (type) {
552 case DEV_PM_QOS_RESUME_LATENCY:
553 ret = blocking_notifier_chain_register(dev->power.qos->resume_latency.notifiers,
554 notifier);
555 break;
556 case DEV_PM_QOS_MIN_FREQUENCY:
557 ret = freq_qos_add_notifier(&dev->power.qos->freq,
558 FREQ_QOS_MIN, notifier);
559 break;
560 case DEV_PM_QOS_MAX_FREQUENCY:
561 ret = freq_qos_add_notifier(&dev->power.qos->freq,
562 FREQ_QOS_MAX, notifier);
563 break;
564 default:
565 WARN_ON(1);
566 ret = -EINVAL;
567 }
568
569unlock:
570 mutex_unlock(&dev_pm_qos_mtx);
571 return ret;
572}
573EXPORT_SYMBOL_GPL(dev_pm_qos_add_notifier);
574
575/**
576 * dev_pm_qos_remove_notifier - deletes notification for changes to target value
577 * of per-device PM QoS constraints
578 *
579 * @dev: target device for the constraint
580 * @notifier: notifier block to be removed.
581 * @type: request type.
582 *
583 * Will remove the notifier from the notification chain that gets called
584 * upon changes to the target value.
585 */
586int dev_pm_qos_remove_notifier(struct device *dev,
587 struct notifier_block *notifier,
588 enum dev_pm_qos_req_type type)
589{
590 int ret = 0;
591
592 mutex_lock(&dev_pm_qos_mtx);
593
594 /* Silently return if the constraints object is not present. */
595 if (IS_ERR_OR_NULL(dev->power.qos))
596 goto unlock;
597
598 switch (type) {
599 case DEV_PM_QOS_RESUME_LATENCY:
600 ret = blocking_notifier_chain_unregister(dev->power.qos->resume_latency.notifiers,
601 notifier);
602 break;
603 case DEV_PM_QOS_MIN_FREQUENCY:
604 ret = freq_qos_remove_notifier(&dev->power.qos->freq,
605 FREQ_QOS_MIN, notifier);
606 break;
607 case DEV_PM_QOS_MAX_FREQUENCY:
608 ret = freq_qos_remove_notifier(&dev->power.qos->freq,
609 FREQ_QOS_MAX, notifier);
610 break;
611 default:
612 WARN_ON(1);
613 ret = -EINVAL;
614 }
615
616unlock:
617 mutex_unlock(&dev_pm_qos_mtx);
618 return ret;
619}
620EXPORT_SYMBOL_GPL(dev_pm_qos_remove_notifier);
621
622/**
623 * dev_pm_qos_add_ancestor_request - Add PM QoS request for device's ancestor.
624 * @dev: Device whose ancestor to add the request for.
625 * @req: Pointer to the preallocated handle.
626 * @type: Type of the request.
627 * @value: Constraint latency value.
628 */
629int dev_pm_qos_add_ancestor_request(struct device *dev,
630 struct dev_pm_qos_request *req,
631 enum dev_pm_qos_req_type type, s32 value)
632{
633 struct device *ancestor = dev->parent;
634 int ret = -ENODEV;
635
636 switch (type) {
637 case DEV_PM_QOS_RESUME_LATENCY:
638 while (ancestor && !ancestor->power.ignore_children)
639 ancestor = ancestor->parent;
640
641 break;
642 case DEV_PM_QOS_LATENCY_TOLERANCE:
643 while (ancestor && !ancestor->power.set_latency_tolerance)
644 ancestor = ancestor->parent;
645
646 break;
647 default:
648 ancestor = NULL;
649 }
650 if (ancestor)
651 ret = dev_pm_qos_add_request(ancestor, req, type, value);
652
653 if (ret < 0)
654 req->dev = NULL;
655
656 return ret;
657}
658EXPORT_SYMBOL_GPL(dev_pm_qos_add_ancestor_request);
659
660static void __dev_pm_qos_drop_user_request(struct device *dev,
661 enum dev_pm_qos_req_type type)
662{
663 struct dev_pm_qos_request *req = NULL;
664
665 switch(type) {
666 case DEV_PM_QOS_RESUME_LATENCY:
667 req = dev->power.qos->resume_latency_req;
668 dev->power.qos->resume_latency_req = NULL;
669 break;
670 case DEV_PM_QOS_LATENCY_TOLERANCE:
671 req = dev->power.qos->latency_tolerance_req;
672 dev->power.qos->latency_tolerance_req = NULL;
673 break;
674 case DEV_PM_QOS_FLAGS:
675 req = dev->power.qos->flags_req;
676 dev->power.qos->flags_req = NULL;
677 break;
678 default:
679 WARN_ON(1);
680 return;
681 }
682 __dev_pm_qos_remove_request(req);
683 kfree(req);
684}
685
686static void dev_pm_qos_drop_user_request(struct device *dev,
687 enum dev_pm_qos_req_type type)
688{
689 mutex_lock(&dev_pm_qos_mtx);
690 __dev_pm_qos_drop_user_request(dev, type);
691 mutex_unlock(&dev_pm_qos_mtx);
692}
693
694/**
695 * dev_pm_qos_expose_latency_limit - Expose PM QoS latency limit to user space.
696 * @dev: Device whose PM QoS latency limit is to be exposed to user space.
697 * @value: Initial value of the latency limit.
698 */
699int dev_pm_qos_expose_latency_limit(struct device *dev, s32 value)
700{
701 struct dev_pm_qos_request *req;
702 int ret;
703
704 if (!device_is_registered(dev) || value < 0)
705 return -EINVAL;
706
707 req = kzalloc(sizeof(*req), GFP_KERNEL);
708 if (!req)
709 return -ENOMEM;
710
711 ret = dev_pm_qos_add_request(dev, req, DEV_PM_QOS_RESUME_LATENCY, value);
712 if (ret < 0) {
713 kfree(req);
714 return ret;
715 }
716
717 mutex_lock(&dev_pm_qos_sysfs_mtx);
718
719 mutex_lock(&dev_pm_qos_mtx);
720
721 if (IS_ERR_OR_NULL(dev->power.qos))
722 ret = -ENODEV;
723 else if (dev->power.qos->resume_latency_req)
724 ret = -EEXIST;
725
726 if (ret < 0) {
727 __dev_pm_qos_remove_request(req);
728 kfree(req);
729 mutex_unlock(&dev_pm_qos_mtx);
730 goto out;
731 }
732 dev->power.qos->resume_latency_req = req;
733
734 mutex_unlock(&dev_pm_qos_mtx);
735
736 ret = pm_qos_sysfs_add_resume_latency(dev);
737 if (ret)
738 dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_RESUME_LATENCY);
739
740 out:
741 mutex_unlock(&dev_pm_qos_sysfs_mtx);
742 return ret;
743}
744EXPORT_SYMBOL_GPL(dev_pm_qos_expose_latency_limit);
745
746static void __dev_pm_qos_hide_latency_limit(struct device *dev)
747{
748 if (!IS_ERR_OR_NULL(dev->power.qos) && dev->power.qos->resume_latency_req)
749 __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_RESUME_LATENCY);
750}
751
752/**
753 * dev_pm_qos_hide_latency_limit - Hide PM QoS latency limit from user space.
754 * @dev: Device whose PM QoS latency limit is to be hidden from user space.
755 */
756void dev_pm_qos_hide_latency_limit(struct device *dev)
757{
758 mutex_lock(&dev_pm_qos_sysfs_mtx);
759
760 pm_qos_sysfs_remove_resume_latency(dev);
761
762 mutex_lock(&dev_pm_qos_mtx);
763 __dev_pm_qos_hide_latency_limit(dev);
764 mutex_unlock(&dev_pm_qos_mtx);
765
766 mutex_unlock(&dev_pm_qos_sysfs_mtx);
767}
768EXPORT_SYMBOL_GPL(dev_pm_qos_hide_latency_limit);
769
770/**
771 * dev_pm_qos_expose_flags - Expose PM QoS flags of a device to user space.
772 * @dev: Device whose PM QoS flags are to be exposed to user space.
773 * @val: Initial values of the flags.
774 */
775int dev_pm_qos_expose_flags(struct device *dev, s32 val)
776{
777 struct dev_pm_qos_request *req;
778 int ret;
779
780 if (!device_is_registered(dev))
781 return -EINVAL;
782
783 req = kzalloc(sizeof(*req), GFP_KERNEL);
784 if (!req)
785 return -ENOMEM;
786
787 ret = dev_pm_qos_add_request(dev, req, DEV_PM_QOS_FLAGS, val);
788 if (ret < 0) {
789 kfree(req);
790 return ret;
791 }
792
793 pm_runtime_get_sync(dev);
794 mutex_lock(&dev_pm_qos_sysfs_mtx);
795
796 mutex_lock(&dev_pm_qos_mtx);
797
798 if (IS_ERR_OR_NULL(dev->power.qos))
799 ret = -ENODEV;
800 else if (dev->power.qos->flags_req)
801 ret = -EEXIST;
802
803 if (ret < 0) {
804 __dev_pm_qos_remove_request(req);
805 kfree(req);
806 mutex_unlock(&dev_pm_qos_mtx);
807 goto out;
808 }
809 dev->power.qos->flags_req = req;
810
811 mutex_unlock(&dev_pm_qos_mtx);
812
813 ret = pm_qos_sysfs_add_flags(dev);
814 if (ret)
815 dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_FLAGS);
816
817 out:
818 mutex_unlock(&dev_pm_qos_sysfs_mtx);
819 pm_runtime_put(dev);
820 return ret;
821}
822EXPORT_SYMBOL_GPL(dev_pm_qos_expose_flags);
823
824static void __dev_pm_qos_hide_flags(struct device *dev)
825{
826 if (!IS_ERR_OR_NULL(dev->power.qos) && dev->power.qos->flags_req)
827 __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_FLAGS);
828}
829
830/**
831 * dev_pm_qos_hide_flags - Hide PM QoS flags of a device from user space.
832 * @dev: Device whose PM QoS flags are to be hidden from user space.
833 */
834void dev_pm_qos_hide_flags(struct device *dev)
835{
836 pm_runtime_get_sync(dev);
837 mutex_lock(&dev_pm_qos_sysfs_mtx);
838
839 pm_qos_sysfs_remove_flags(dev);
840
841 mutex_lock(&dev_pm_qos_mtx);
842 __dev_pm_qos_hide_flags(dev);
843 mutex_unlock(&dev_pm_qos_mtx);
844
845 mutex_unlock(&dev_pm_qos_sysfs_mtx);
846 pm_runtime_put(dev);
847}
848EXPORT_SYMBOL_GPL(dev_pm_qos_hide_flags);
849
850/**
851 * dev_pm_qos_update_flags - Update PM QoS flags request owned by user space.
852 * @dev: Device to update the PM QoS flags request for.
853 * @mask: Flags to set/clear.
854 * @set: Whether to set or clear the flags (true means set).
855 */
856int dev_pm_qos_update_flags(struct device *dev, s32 mask, bool set)
857{
858 s32 value;
859 int ret;
860
861 pm_runtime_get_sync(dev);
862 mutex_lock(&dev_pm_qos_mtx);
863
864 if (IS_ERR_OR_NULL(dev->power.qos) || !dev->power.qos->flags_req) {
865 ret = -EINVAL;
866 goto out;
867 }
868
869 value = dev_pm_qos_requested_flags(dev);
870 if (set)
871 value |= mask;
872 else
873 value &= ~mask;
874
875 ret = __dev_pm_qos_update_request(dev->power.qos->flags_req, value);
876
877 out:
878 mutex_unlock(&dev_pm_qos_mtx);
879 pm_runtime_put(dev);
880 return ret;
881}
882
883/**
884 * dev_pm_qos_get_user_latency_tolerance - Get user space latency tolerance.
885 * @dev: Device to obtain the user space latency tolerance for.
886 */
887s32 dev_pm_qos_get_user_latency_tolerance(struct device *dev)
888{
889 s32 ret;
890
891 mutex_lock(&dev_pm_qos_mtx);
892 ret = IS_ERR_OR_NULL(dev->power.qos)
893 || !dev->power.qos->latency_tolerance_req ?
894 PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT :
895 dev->power.qos->latency_tolerance_req->data.pnode.prio;
896 mutex_unlock(&dev_pm_qos_mtx);
897 return ret;
898}
899
900/**
901 * dev_pm_qos_update_user_latency_tolerance - Update user space latency tolerance.
902 * @dev: Device to update the user space latency tolerance for.
903 * @val: New user space latency tolerance for @dev (negative values disable).
904 */
905int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
906{
907 int ret;
908
909 mutex_lock(&dev_pm_qos_mtx);
910
911 if (IS_ERR_OR_NULL(dev->power.qos)
912 || !dev->power.qos->latency_tolerance_req) {
913 struct dev_pm_qos_request *req;
914
915 if (val < 0) {
916 if (val == PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT)
917 ret = 0;
918 else
919 ret = -EINVAL;
920 goto out;
921 }
922 req = kzalloc(sizeof(*req), GFP_KERNEL);
923 if (!req) {
924 ret = -ENOMEM;
925 goto out;
926 }
927 ret = __dev_pm_qos_add_request(dev, req, DEV_PM_QOS_LATENCY_TOLERANCE, val);
928 if (ret < 0) {
929 kfree(req);
930 goto out;
931 }
932 dev->power.qos->latency_tolerance_req = req;
933 } else {
934 if (val < 0) {
935 __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_LATENCY_TOLERANCE);
936 ret = 0;
937 } else {
938 ret = __dev_pm_qos_update_request(dev->power.qos->latency_tolerance_req, val);
939 }
940 }
941
942 out:
943 mutex_unlock(&dev_pm_qos_mtx);
944 return ret;
945}
946EXPORT_SYMBOL_GPL(dev_pm_qos_update_user_latency_tolerance);
947
948/**
949 * dev_pm_qos_expose_latency_tolerance - Expose latency tolerance to userspace
950 * @dev: Device whose latency tolerance to expose
951 */
952int dev_pm_qos_expose_latency_tolerance(struct device *dev)
953{
954 int ret;
955
956 if (!dev->power.set_latency_tolerance)
957 return -EINVAL;
958
959 mutex_lock(&dev_pm_qos_sysfs_mtx);
960 ret = pm_qos_sysfs_add_latency_tolerance(dev);
961 mutex_unlock(&dev_pm_qos_sysfs_mtx);
962
963 return ret;
964}
965EXPORT_SYMBOL_GPL(dev_pm_qos_expose_latency_tolerance);
966
967/**
968 * dev_pm_qos_hide_latency_tolerance - Hide latency tolerance from userspace
969 * @dev: Device whose latency tolerance to hide
970 */
971void dev_pm_qos_hide_latency_tolerance(struct device *dev)
972{
973 mutex_lock(&dev_pm_qos_sysfs_mtx);
974 pm_qos_sysfs_remove_latency_tolerance(dev);
975 mutex_unlock(&dev_pm_qos_sysfs_mtx);
976
977 /* Remove the request from user space now */
978 pm_runtime_get_sync(dev);
979 dev_pm_qos_update_user_latency_tolerance(dev,
980 PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT);
981 pm_runtime_put(dev);
982}
983EXPORT_SYMBOL_GPL(dev_pm_qos_hide_latency_tolerance);