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