Loading...
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// 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 if (type == DEV_PM_QOS_RESUME_LATENCY) {
119 ret = IS_ERR_OR_NULL(qos) ? PM_QOS_RESUME_LATENCY_NO_CONSTRAINT
120 : pm_qos_read_value(&qos->resume_latency);
121 } else {
122 WARN_ON(1);
123 ret = 0;
124 }
125
126 spin_unlock_irqrestore(&dev->power.lock, flags);
127
128 return ret;
129}
130
131/**
132 * apply_constraint - Add/modify/remove device PM QoS request.
133 * @req: Constraint request to apply
134 * @action: Action to perform (add/update/remove).
135 * @value: Value to assign to the QoS request.
136 *
137 * Internal function to update the constraints list using the PM QoS core
138 * code and if needed call the per-device callbacks.
139 */
140static int apply_constraint(struct dev_pm_qos_request *req,
141 enum pm_qos_req_action action, s32 value)
142{
143 struct dev_pm_qos *qos = req->dev->power.qos;
144 int ret;
145
146 switch(req->type) {
147 case DEV_PM_QOS_RESUME_LATENCY:
148 if (WARN_ON(action != PM_QOS_REMOVE_REQ && value < 0))
149 value = 0;
150
151 ret = pm_qos_update_target(&qos->resume_latency,
152 &req->data.pnode, action, value);
153 break;
154 case DEV_PM_QOS_LATENCY_TOLERANCE:
155 ret = pm_qos_update_target(&qos->latency_tolerance,
156 &req->data.pnode, action, value);
157 if (ret) {
158 value = pm_qos_read_value(&qos->latency_tolerance);
159 req->dev->power.set_latency_tolerance(req->dev, value);
160 }
161 break;
162 case DEV_PM_QOS_FLAGS:
163 ret = pm_qos_update_flags(&qos->flags, &req->data.flr,
164 action, value);
165 break;
166 default:
167 ret = -EINVAL;
168 }
169
170 return ret;
171}
172
173/*
174 * dev_pm_qos_constraints_allocate
175 * @dev: device to allocate data for
176 *
177 * Called at the first call to add_request, for constraint data allocation
178 * Must be called with the dev_pm_qos_mtx mutex held
179 */
180static int dev_pm_qos_constraints_allocate(struct device *dev)
181{
182 struct dev_pm_qos *qos;
183 struct pm_qos_constraints *c;
184 struct blocking_notifier_head *n;
185
186 qos = kzalloc(sizeof(*qos), GFP_KERNEL);
187 if (!qos)
188 return -ENOMEM;
189
190 n = kzalloc(3 * sizeof(*n), GFP_KERNEL);
191 if (!n) {
192 kfree(qos);
193 return -ENOMEM;
194 }
195
196 c = &qos->resume_latency;
197 plist_head_init(&c->list);
198 c->target_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;
199 c->default_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;
200 c->no_constraint_value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT;
201 c->type = PM_QOS_MIN;
202 c->notifiers = n;
203 BLOCKING_INIT_NOTIFIER_HEAD(n);
204
205 c = &qos->latency_tolerance;
206 plist_head_init(&c->list);
207 c->target_value = PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE;
208 c->default_value = PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE;
209 c->no_constraint_value = PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT;
210 c->type = PM_QOS_MIN;
211
212 INIT_LIST_HEAD(&qos->flags.list);
213
214 spin_lock_irq(&dev->power.lock);
215 dev->power.qos = qos;
216 spin_unlock_irq(&dev->power.lock);
217
218 return 0;
219}
220
221static void __dev_pm_qos_hide_latency_limit(struct device *dev);
222static void __dev_pm_qos_hide_flags(struct device *dev);
223
224/**
225 * dev_pm_qos_constraints_destroy
226 * @dev: target device
227 *
228 * Called from the device PM subsystem on device removal under device_pm_lock().
229 */
230void dev_pm_qos_constraints_destroy(struct device *dev)
231{
232 struct dev_pm_qos *qos;
233 struct dev_pm_qos_request *req, *tmp;
234 struct pm_qos_constraints *c;
235 struct pm_qos_flags *f;
236
237 mutex_lock(&dev_pm_qos_sysfs_mtx);
238
239 /*
240 * If the device's PM QoS resume latency limit or PM QoS flags have been
241 * exposed to user space, they have to be hidden at this point.
242 */
243 pm_qos_sysfs_remove_resume_latency(dev);
244 pm_qos_sysfs_remove_flags(dev);
245
246 mutex_lock(&dev_pm_qos_mtx);
247
248 __dev_pm_qos_hide_latency_limit(dev);
249 __dev_pm_qos_hide_flags(dev);
250
251 qos = dev->power.qos;
252 if (!qos)
253 goto out;
254
255 /* Flush the constraints lists for the device. */
256 c = &qos->resume_latency;
257 plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) {
258 /*
259 * Update constraints list and call the notification
260 * callbacks if needed
261 */
262 apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
263 memset(req, 0, sizeof(*req));
264 }
265
266 c = &qos->latency_tolerance;
267 plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) {
268 apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
269 memset(req, 0, sizeof(*req));
270 }
271
272 f = &qos->flags;
273 list_for_each_entry_safe(req, tmp, &f->list, data.flr.node) {
274 apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
275 memset(req, 0, sizeof(*req));
276 }
277
278 spin_lock_irq(&dev->power.lock);
279 dev->power.qos = ERR_PTR(-ENODEV);
280 spin_unlock_irq(&dev->power.lock);
281
282 kfree(qos->resume_latency.notifiers);
283 kfree(qos);
284
285 out:
286 mutex_unlock(&dev_pm_qos_mtx);
287
288 mutex_unlock(&dev_pm_qos_sysfs_mtx);
289}
290
291static bool dev_pm_qos_invalid_req_type(struct device *dev,
292 enum dev_pm_qos_req_type type)
293{
294 return type == DEV_PM_QOS_LATENCY_TOLERANCE &&
295 !dev->power.set_latency_tolerance;
296}
297
298static int __dev_pm_qos_add_request(struct device *dev,
299 struct dev_pm_qos_request *req,
300 enum dev_pm_qos_req_type type, s32 value)
301{
302 int ret = 0;
303
304 if (!dev || !req || dev_pm_qos_invalid_req_type(dev, type))
305 return -EINVAL;
306
307 if (WARN(dev_pm_qos_request_active(req),
308 "%s() called for already added request\n", __func__))
309 return -EINVAL;
310
311 if (IS_ERR(dev->power.qos))
312 ret = -ENODEV;
313 else if (!dev->power.qos)
314 ret = dev_pm_qos_constraints_allocate(dev);
315
316 trace_dev_pm_qos_add_request(dev_name(dev), type, value);
317 if (!ret) {
318 req->dev = dev;
319 req->type = type;
320 ret = apply_constraint(req, PM_QOS_ADD_REQ, value);
321 }
322 return ret;
323}
324
325/**
326 * dev_pm_qos_add_request - inserts new qos request into the list
327 * @dev: target device for the constraint
328 * @req: pointer to a preallocated handle
329 * @type: type of the request
330 * @value: defines the qos request
331 *
332 * This function inserts a new entry in the device constraints list of
333 * requested qos performance characteristics. It recomputes the aggregate
334 * QoS expectations of parameters and initializes the dev_pm_qos_request
335 * handle. Caller needs to save this handle for later use in updates and
336 * removal.
337 *
338 * Returns 1 if the aggregated constraint value has changed,
339 * 0 if the aggregated constraint value has not changed,
340 * -EINVAL in case of wrong parameters, -ENOMEM if there's not enough memory
341 * to allocate for data structures, -ENODEV if the device has just been removed
342 * from the system.
343 *
344 * Callers should ensure that the target device is not RPM_SUSPENDED before
345 * using this function for requests of type DEV_PM_QOS_FLAGS.
346 */
347int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
348 enum dev_pm_qos_req_type type, s32 value)
349{
350 int ret;
351
352 mutex_lock(&dev_pm_qos_mtx);
353 ret = __dev_pm_qos_add_request(dev, req, type, value);
354 mutex_unlock(&dev_pm_qos_mtx);
355 return ret;
356}
357EXPORT_SYMBOL_GPL(dev_pm_qos_add_request);
358
359/**
360 * __dev_pm_qos_update_request - Modify an existing device PM QoS request.
361 * @req : PM QoS request to modify.
362 * @new_value: New value to request.
363 */
364static int __dev_pm_qos_update_request(struct dev_pm_qos_request *req,
365 s32 new_value)
366{
367 s32 curr_value;
368 int ret = 0;
369
370 if (!req) /*guard against callers passing in null */
371 return -EINVAL;
372
373 if (WARN(!dev_pm_qos_request_active(req),
374 "%s() called for unknown object\n", __func__))
375 return -EINVAL;
376
377 if (IS_ERR_OR_NULL(req->dev->power.qos))
378 return -ENODEV;
379
380 switch(req->type) {
381 case DEV_PM_QOS_RESUME_LATENCY:
382 case DEV_PM_QOS_LATENCY_TOLERANCE:
383 curr_value = req->data.pnode.prio;
384 break;
385 case DEV_PM_QOS_FLAGS:
386 curr_value = req->data.flr.flags;
387 break;
388 default:
389 return -EINVAL;
390 }
391
392 trace_dev_pm_qos_update_request(dev_name(req->dev), req->type,
393 new_value);
394 if (curr_value != new_value)
395 ret = apply_constraint(req, PM_QOS_UPDATE_REQ, new_value);
396
397 return ret;
398}
399
400/**
401 * dev_pm_qos_update_request - modifies an existing qos request
402 * @req : handle to list element holding a dev_pm_qos request to use
403 * @new_value: defines the qos request
404 *
405 * Updates an existing dev PM qos request along with updating the
406 * target value.
407 *
408 * Attempts are made to make this code callable on hot code paths.
409 *
410 * Returns 1 if the aggregated constraint value has changed,
411 * 0 if the aggregated constraint value has not changed,
412 * -EINVAL in case of wrong parameters, -ENODEV if the device has been
413 * removed from the system
414 *
415 * Callers should ensure that the target device is not RPM_SUSPENDED before
416 * using this function for requests of type DEV_PM_QOS_FLAGS.
417 */
418int dev_pm_qos_update_request(struct dev_pm_qos_request *req, s32 new_value)
419{
420 int ret;
421
422 mutex_lock(&dev_pm_qos_mtx);
423 ret = __dev_pm_qos_update_request(req, new_value);
424 mutex_unlock(&dev_pm_qos_mtx);
425 return ret;
426}
427EXPORT_SYMBOL_GPL(dev_pm_qos_update_request);
428
429static int __dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
430{
431 int ret;
432
433 if (!req) /*guard against callers passing in null */
434 return -EINVAL;
435
436 if (WARN(!dev_pm_qos_request_active(req),
437 "%s() called for unknown object\n", __func__))
438 return -EINVAL;
439
440 if (IS_ERR_OR_NULL(req->dev->power.qos))
441 return -ENODEV;
442
443 trace_dev_pm_qos_remove_request(dev_name(req->dev), req->type,
444 PM_QOS_DEFAULT_VALUE);
445 ret = apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
446 memset(req, 0, sizeof(*req));
447 return ret;
448}
449
450/**
451 * dev_pm_qos_remove_request - modifies an existing qos request
452 * @req: handle to request list element
453 *
454 * Will remove pm qos request from the list of constraints and
455 * recompute the current target value. Call this on slow code paths.
456 *
457 * Returns 1 if the aggregated constraint value has changed,
458 * 0 if the aggregated constraint value has not changed,
459 * -EINVAL in case of wrong parameters, -ENODEV if the device has been
460 * removed from the system
461 *
462 * Callers should ensure that the target device is not RPM_SUSPENDED before
463 * using this function for requests of type DEV_PM_QOS_FLAGS.
464 */
465int dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
466{
467 int ret;
468
469 mutex_lock(&dev_pm_qos_mtx);
470 ret = __dev_pm_qos_remove_request(req);
471 mutex_unlock(&dev_pm_qos_mtx);
472 return ret;
473}
474EXPORT_SYMBOL_GPL(dev_pm_qos_remove_request);
475
476/**
477 * dev_pm_qos_add_notifier - sets notification entry for changes to target value
478 * of per-device PM QoS constraints
479 *
480 * @dev: target device for the constraint
481 * @notifier: notifier block managed by caller.
482 * @type: request type.
483 *
484 * Will register the notifier into a notification chain that gets called
485 * upon changes to the target value for the device.
486 *
487 * If the device's constraints object doesn't exist when this routine is called,
488 * it will be created (or error code will be returned if that fails).
489 */
490int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier,
491 enum dev_pm_qos_req_type type)
492{
493 int ret = 0;
494
495 mutex_lock(&dev_pm_qos_mtx);
496
497 if (IS_ERR(dev->power.qos))
498 ret = -ENODEV;
499 else if (!dev->power.qos)
500 ret = dev_pm_qos_constraints_allocate(dev);
501
502 if (ret)
503 goto unlock;
504
505 switch (type) {
506 case DEV_PM_QOS_RESUME_LATENCY:
507 ret = blocking_notifier_chain_register(dev->power.qos->resume_latency.notifiers,
508 notifier);
509 break;
510 default:
511 WARN_ON(1);
512 ret = -EINVAL;
513 }
514
515unlock:
516 mutex_unlock(&dev_pm_qos_mtx);
517 return ret;
518}
519EXPORT_SYMBOL_GPL(dev_pm_qos_add_notifier);
520
521/**
522 * dev_pm_qos_remove_notifier - deletes notification for changes to target value
523 * of per-device PM QoS constraints
524 *
525 * @dev: target device for the constraint
526 * @notifier: notifier block to be removed.
527 * @type: request type.
528 *
529 * Will remove the notifier from the notification chain that gets called
530 * upon changes to the target value.
531 */
532int dev_pm_qos_remove_notifier(struct device *dev,
533 struct notifier_block *notifier,
534 enum dev_pm_qos_req_type type)
535{
536 int ret = 0;
537
538 mutex_lock(&dev_pm_qos_mtx);
539
540 /* Silently return if the constraints object is not present. */
541 if (IS_ERR_OR_NULL(dev->power.qos))
542 goto unlock;
543
544 switch (type) {
545 case DEV_PM_QOS_RESUME_LATENCY:
546 ret = blocking_notifier_chain_unregister(dev->power.qos->resume_latency.notifiers,
547 notifier);
548 break;
549 default:
550 WARN_ON(1);
551 ret = -EINVAL;
552 }
553
554unlock:
555 mutex_unlock(&dev_pm_qos_mtx);
556 return ret;
557}
558EXPORT_SYMBOL_GPL(dev_pm_qos_remove_notifier);
559
560/**
561 * dev_pm_qos_add_ancestor_request - Add PM QoS request for device's ancestor.
562 * @dev: Device whose ancestor to add the request for.
563 * @req: Pointer to the preallocated handle.
564 * @type: Type of the request.
565 * @value: Constraint latency value.
566 */
567int dev_pm_qos_add_ancestor_request(struct device *dev,
568 struct dev_pm_qos_request *req,
569 enum dev_pm_qos_req_type type, s32 value)
570{
571 struct device *ancestor = dev->parent;
572 int ret = -ENODEV;
573
574 switch (type) {
575 case DEV_PM_QOS_RESUME_LATENCY:
576 while (ancestor && !ancestor->power.ignore_children)
577 ancestor = ancestor->parent;
578
579 break;
580 case DEV_PM_QOS_LATENCY_TOLERANCE:
581 while (ancestor && !ancestor->power.set_latency_tolerance)
582 ancestor = ancestor->parent;
583
584 break;
585 default:
586 ancestor = NULL;
587 }
588 if (ancestor)
589 ret = dev_pm_qos_add_request(ancestor, req, type, value);
590
591 if (ret < 0)
592 req->dev = NULL;
593
594 return ret;
595}
596EXPORT_SYMBOL_GPL(dev_pm_qos_add_ancestor_request);
597
598static void __dev_pm_qos_drop_user_request(struct device *dev,
599 enum dev_pm_qos_req_type type)
600{
601 struct dev_pm_qos_request *req = NULL;
602
603 switch(type) {
604 case DEV_PM_QOS_RESUME_LATENCY:
605 req = dev->power.qos->resume_latency_req;
606 dev->power.qos->resume_latency_req = NULL;
607 break;
608 case DEV_PM_QOS_LATENCY_TOLERANCE:
609 req = dev->power.qos->latency_tolerance_req;
610 dev->power.qos->latency_tolerance_req = NULL;
611 break;
612 case DEV_PM_QOS_FLAGS:
613 req = dev->power.qos->flags_req;
614 dev->power.qos->flags_req = NULL;
615 break;
616 default:
617 WARN_ON(1);
618 return;
619 }
620 __dev_pm_qos_remove_request(req);
621 kfree(req);
622}
623
624static void dev_pm_qos_drop_user_request(struct device *dev,
625 enum dev_pm_qos_req_type type)
626{
627 mutex_lock(&dev_pm_qos_mtx);
628 __dev_pm_qos_drop_user_request(dev, type);
629 mutex_unlock(&dev_pm_qos_mtx);
630}
631
632/**
633 * dev_pm_qos_expose_latency_limit - Expose PM QoS latency limit to user space.
634 * @dev: Device whose PM QoS latency limit is to be exposed to user space.
635 * @value: Initial value of the latency limit.
636 */
637int dev_pm_qos_expose_latency_limit(struct device *dev, s32 value)
638{
639 struct dev_pm_qos_request *req;
640 int ret;
641
642 if (!device_is_registered(dev) || value < 0)
643 return -EINVAL;
644
645 req = kzalloc(sizeof(*req), GFP_KERNEL);
646 if (!req)
647 return -ENOMEM;
648
649 ret = dev_pm_qos_add_request(dev, req, DEV_PM_QOS_RESUME_LATENCY, value);
650 if (ret < 0) {
651 kfree(req);
652 return ret;
653 }
654
655 mutex_lock(&dev_pm_qos_sysfs_mtx);
656
657 mutex_lock(&dev_pm_qos_mtx);
658
659 if (IS_ERR_OR_NULL(dev->power.qos))
660 ret = -ENODEV;
661 else if (dev->power.qos->resume_latency_req)
662 ret = -EEXIST;
663
664 if (ret < 0) {
665 __dev_pm_qos_remove_request(req);
666 kfree(req);
667 mutex_unlock(&dev_pm_qos_mtx);
668 goto out;
669 }
670 dev->power.qos->resume_latency_req = req;
671
672 mutex_unlock(&dev_pm_qos_mtx);
673
674 ret = pm_qos_sysfs_add_resume_latency(dev);
675 if (ret)
676 dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_RESUME_LATENCY);
677
678 out:
679 mutex_unlock(&dev_pm_qos_sysfs_mtx);
680 return ret;
681}
682EXPORT_SYMBOL_GPL(dev_pm_qos_expose_latency_limit);
683
684static void __dev_pm_qos_hide_latency_limit(struct device *dev)
685{
686 if (!IS_ERR_OR_NULL(dev->power.qos) && dev->power.qos->resume_latency_req)
687 __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_RESUME_LATENCY);
688}
689
690/**
691 * dev_pm_qos_hide_latency_limit - Hide PM QoS latency limit from user space.
692 * @dev: Device whose PM QoS latency limit is to be hidden from user space.
693 */
694void dev_pm_qos_hide_latency_limit(struct device *dev)
695{
696 mutex_lock(&dev_pm_qos_sysfs_mtx);
697
698 pm_qos_sysfs_remove_resume_latency(dev);
699
700 mutex_lock(&dev_pm_qos_mtx);
701 __dev_pm_qos_hide_latency_limit(dev);
702 mutex_unlock(&dev_pm_qos_mtx);
703
704 mutex_unlock(&dev_pm_qos_sysfs_mtx);
705}
706EXPORT_SYMBOL_GPL(dev_pm_qos_hide_latency_limit);
707
708/**
709 * dev_pm_qos_expose_flags - Expose PM QoS flags of a device to user space.
710 * @dev: Device whose PM QoS flags are to be exposed to user space.
711 * @val: Initial values of the flags.
712 */
713int dev_pm_qos_expose_flags(struct device *dev, s32 val)
714{
715 struct dev_pm_qos_request *req;
716 int ret;
717
718 if (!device_is_registered(dev))
719 return -EINVAL;
720
721 req = kzalloc(sizeof(*req), GFP_KERNEL);
722 if (!req)
723 return -ENOMEM;
724
725 ret = dev_pm_qos_add_request(dev, req, DEV_PM_QOS_FLAGS, val);
726 if (ret < 0) {
727 kfree(req);
728 return ret;
729 }
730
731 pm_runtime_get_sync(dev);
732 mutex_lock(&dev_pm_qos_sysfs_mtx);
733
734 mutex_lock(&dev_pm_qos_mtx);
735
736 if (IS_ERR_OR_NULL(dev->power.qos))
737 ret = -ENODEV;
738 else if (dev->power.qos->flags_req)
739 ret = -EEXIST;
740
741 if (ret < 0) {
742 __dev_pm_qos_remove_request(req);
743 kfree(req);
744 mutex_unlock(&dev_pm_qos_mtx);
745 goto out;
746 }
747 dev->power.qos->flags_req = req;
748
749 mutex_unlock(&dev_pm_qos_mtx);
750
751 ret = pm_qos_sysfs_add_flags(dev);
752 if (ret)
753 dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_FLAGS);
754
755 out:
756 mutex_unlock(&dev_pm_qos_sysfs_mtx);
757 pm_runtime_put(dev);
758 return ret;
759}
760EXPORT_SYMBOL_GPL(dev_pm_qos_expose_flags);
761
762static void __dev_pm_qos_hide_flags(struct device *dev)
763{
764 if (!IS_ERR_OR_NULL(dev->power.qos) && dev->power.qos->flags_req)
765 __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_FLAGS);
766}
767
768/**
769 * dev_pm_qos_hide_flags - Hide PM QoS flags of a device from user space.
770 * @dev: Device whose PM QoS flags are to be hidden from user space.
771 */
772void dev_pm_qos_hide_flags(struct device *dev)
773{
774 pm_runtime_get_sync(dev);
775 mutex_lock(&dev_pm_qos_sysfs_mtx);
776
777 pm_qos_sysfs_remove_flags(dev);
778
779 mutex_lock(&dev_pm_qos_mtx);
780 __dev_pm_qos_hide_flags(dev);
781 mutex_unlock(&dev_pm_qos_mtx);
782
783 mutex_unlock(&dev_pm_qos_sysfs_mtx);
784 pm_runtime_put(dev);
785}
786EXPORT_SYMBOL_GPL(dev_pm_qos_hide_flags);
787
788/**
789 * dev_pm_qos_update_flags - Update PM QoS flags request owned by user space.
790 * @dev: Device to update the PM QoS flags request for.
791 * @mask: Flags to set/clear.
792 * @set: Whether to set or clear the flags (true means set).
793 */
794int dev_pm_qos_update_flags(struct device *dev, s32 mask, bool set)
795{
796 s32 value;
797 int ret;
798
799 pm_runtime_get_sync(dev);
800 mutex_lock(&dev_pm_qos_mtx);
801
802 if (IS_ERR_OR_NULL(dev->power.qos) || !dev->power.qos->flags_req) {
803 ret = -EINVAL;
804 goto out;
805 }
806
807 value = dev_pm_qos_requested_flags(dev);
808 if (set)
809 value |= mask;
810 else
811 value &= ~mask;
812
813 ret = __dev_pm_qos_update_request(dev->power.qos->flags_req, value);
814
815 out:
816 mutex_unlock(&dev_pm_qos_mtx);
817 pm_runtime_put(dev);
818 return ret;
819}
820
821/**
822 * dev_pm_qos_get_user_latency_tolerance - Get user space latency tolerance.
823 * @dev: Device to obtain the user space latency tolerance for.
824 */
825s32 dev_pm_qos_get_user_latency_tolerance(struct device *dev)
826{
827 s32 ret;
828
829 mutex_lock(&dev_pm_qos_mtx);
830 ret = IS_ERR_OR_NULL(dev->power.qos)
831 || !dev->power.qos->latency_tolerance_req ?
832 PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT :
833 dev->power.qos->latency_tolerance_req->data.pnode.prio;
834 mutex_unlock(&dev_pm_qos_mtx);
835 return ret;
836}
837
838/**
839 * dev_pm_qos_update_user_latency_tolerance - Update user space latency tolerance.
840 * @dev: Device to update the user space latency tolerance for.
841 * @val: New user space latency tolerance for @dev (negative values disable).
842 */
843int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
844{
845 int ret;
846
847 mutex_lock(&dev_pm_qos_mtx);
848
849 if (IS_ERR_OR_NULL(dev->power.qos)
850 || !dev->power.qos->latency_tolerance_req) {
851 struct dev_pm_qos_request *req;
852
853 if (val < 0) {
854 if (val == PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT)
855 ret = 0;
856 else
857 ret = -EINVAL;
858 goto out;
859 }
860 req = kzalloc(sizeof(*req), GFP_KERNEL);
861 if (!req) {
862 ret = -ENOMEM;
863 goto out;
864 }
865 ret = __dev_pm_qos_add_request(dev, req, DEV_PM_QOS_LATENCY_TOLERANCE, val);
866 if (ret < 0) {
867 kfree(req);
868 goto out;
869 }
870 dev->power.qos->latency_tolerance_req = req;
871 } else {
872 if (val < 0) {
873 __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_LATENCY_TOLERANCE);
874 ret = 0;
875 } else {
876 ret = __dev_pm_qos_update_request(dev->power.qos->latency_tolerance_req, val);
877 }
878 }
879
880 out:
881 mutex_unlock(&dev_pm_qos_mtx);
882 return ret;
883}
884EXPORT_SYMBOL_GPL(dev_pm_qos_update_user_latency_tolerance);
885
886/**
887 * dev_pm_qos_expose_latency_tolerance - Expose latency tolerance to userspace
888 * @dev: Device whose latency tolerance to expose
889 */
890int dev_pm_qos_expose_latency_tolerance(struct device *dev)
891{
892 int ret;
893
894 if (!dev->power.set_latency_tolerance)
895 return -EINVAL;
896
897 mutex_lock(&dev_pm_qos_sysfs_mtx);
898 ret = pm_qos_sysfs_add_latency_tolerance(dev);
899 mutex_unlock(&dev_pm_qos_sysfs_mtx);
900
901 return ret;
902}
903EXPORT_SYMBOL_GPL(dev_pm_qos_expose_latency_tolerance);
904
905/**
906 * dev_pm_qos_hide_latency_tolerance - Hide latency tolerance from userspace
907 * @dev: Device whose latency tolerance to hide
908 */
909void dev_pm_qos_hide_latency_tolerance(struct device *dev)
910{
911 mutex_lock(&dev_pm_qos_sysfs_mtx);
912 pm_qos_sysfs_remove_latency_tolerance(dev);
913 mutex_unlock(&dev_pm_qos_sysfs_mtx);
914
915 /* Remove the request from user space now */
916 pm_runtime_get_sync(dev);
917 dev_pm_qos_update_user_latency_tolerance(dev,
918 PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT);
919 pm_runtime_put(dev);
920}
921EXPORT_SYMBOL_GPL(dev_pm_qos_hide_latency_tolerance);