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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// SPDX-License-Identifier: GPL-2.0
2/*
3 * Devices PM QoS constraints management
4 *
5 * Copyright (C) 2011 Texas Instruments, Inc.
6 *
7 * This module exposes the interface to kernel space for specifying
8 * per-device PM QoS dependencies. It provides infrastructure for registration
9 * of:
10 *
11 * Dependents on a QoS value : register requests
12 * Watchers of QoS value : get notified when target QoS value changes
13 *
14 * This QoS design is best effort based. Dependents register their QoS needs.
15 * Watchers register to keep track of the current QoS needs of the system.
16 * Watchers can register a per-device notification callback using the
17 * dev_pm_qos_*_notifier API. The notification chain data is stored in the
18 * per-device constraint data struct.
19 *
20 * Note about the per-device constraint data struct allocation:
21 * . The per-device constraints data struct ptr is stored into the device
22 * dev_pm_info.
23 * . To minimize the data usage by the per-device constraints, the data struct
24 * is only allocated at the first call to dev_pm_qos_add_request.
25 * . The data is later free'd when the device is removed from the system.
26 * . A global mutex protects the constraints users from the data being
27 * allocated and free'd.
28 */
29
30#include <linux/pm_qos.h>
31#include <linux/spinlock.h>
32#include <linux/slab.h>
33#include <linux/device.h>
34#include <linux/mutex.h>
35#include <linux/export.h>
36#include <linux/pm_runtime.h>
37#include <linux/err.h>
38#include <trace/events/power.h>
39
40#include "power.h"
41
42static DEFINE_MUTEX(dev_pm_qos_mtx);
43static DEFINE_MUTEX(dev_pm_qos_sysfs_mtx);
44
45/**
46 * __dev_pm_qos_flags - Check PM QoS flags for a given device.
47 * @dev: Device to check the PM QoS flags for.
48 * @mask: Flags to check against.
49 *
50 * This routine must be called with dev->power.lock held.
51 */
52enum pm_qos_flags_status __dev_pm_qos_flags(struct device *dev, s32 mask)
53{
54 struct dev_pm_qos *qos = dev->power.qos;
55 struct pm_qos_flags *pqf;
56 s32 val;
57
58 lockdep_assert_held(&dev->power.lock);
59
60 if (IS_ERR_OR_NULL(qos))
61 return PM_QOS_FLAGS_UNDEFINED;
62
63 pqf = &qos->flags;
64 if (list_empty(&pqf->list))
65 return PM_QOS_FLAGS_UNDEFINED;
66
67 val = pqf->effective_flags & mask;
68 if (val)
69 return (val == mask) ? PM_QOS_FLAGS_ALL : PM_QOS_FLAGS_SOME;
70
71 return PM_QOS_FLAGS_NONE;
72}
73
74/**
75 * dev_pm_qos_flags - Check PM QoS flags for a given device (locked).
76 * @dev: Device to check the PM QoS flags for.
77 * @mask: Flags to check against.
78 */
79enum pm_qos_flags_status dev_pm_qos_flags(struct device *dev, s32 mask)
80{
81 unsigned long irqflags;
82 enum pm_qos_flags_status ret;
83
84 spin_lock_irqsave(&dev->power.lock, irqflags);
85 ret = __dev_pm_qos_flags(dev, mask);
86 spin_unlock_irqrestore(&dev->power.lock, irqflags);
87
88 return ret;
89}
90EXPORT_SYMBOL_GPL(dev_pm_qos_flags);
91
92/**
93 * __dev_pm_qos_resume_latency - Get resume latency constraint for a given device.
94 * @dev: Device to get the PM QoS constraint value for.
95 *
96 * This routine must be called with dev->power.lock held.
97 */
98s32 __dev_pm_qos_resume_latency(struct device *dev)
99{
100 lockdep_assert_held(&dev->power.lock);
101
102 return dev_pm_qos_raw_resume_latency(dev);
103}
104
105/**
106 * dev_pm_qos_read_value - Get PM QoS constraint for a given device (locked).
107 * @dev: Device to get the PM QoS constraint value for.
108 * @type: QoS request type.
109 */
110s32 dev_pm_qos_read_value(struct device *dev, enum dev_pm_qos_req_type type)
111{
112 struct dev_pm_qos *qos = dev->power.qos;
113 unsigned long flags;
114 s32 ret;
115
116 spin_lock_irqsave(&dev->power.lock, flags);
117
118 switch (type) {
119 case DEV_PM_QOS_RESUME_LATENCY:
120 ret = IS_ERR_OR_NULL(qos) ? PM_QOS_RESUME_LATENCY_NO_CONSTRAINT
121 : pm_qos_read_value(&qos->resume_latency);
122 break;
123 case DEV_PM_QOS_MIN_FREQUENCY:
124 ret = IS_ERR_OR_NULL(qos) ? PM_QOS_MIN_FREQUENCY_DEFAULT_VALUE
125 : freq_qos_read_value(&qos->freq, FREQ_QOS_MIN);
126 break;
127 case DEV_PM_QOS_MAX_FREQUENCY:
128 ret = IS_ERR_OR_NULL(qos) ? PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE
129 : freq_qos_read_value(&qos->freq, FREQ_QOS_MAX);
130 break;
131 default:
132 WARN_ON(1);
133 ret = 0;
134 }
135
136 spin_unlock_irqrestore(&dev->power.lock, flags);
137
138 return ret;
139}
140EXPORT_SYMBOL_GPL(dev_pm_qos_read_value);
141
142/**
143 * apply_constraint - Add/modify/remove device PM QoS request.
144 * @req: Constraint request to apply
145 * @action: Action to perform (add/update/remove).
146 * @value: Value to assign to the QoS request.
147 *
148 * Internal function to update the constraints list using the PM QoS core
149 * code and if needed call the per-device callbacks.
150 */
151static int apply_constraint(struct dev_pm_qos_request *req,
152 enum pm_qos_req_action action, s32 value)
153{
154 struct dev_pm_qos *qos = req->dev->power.qos;
155 int ret;
156
157 switch(req->type) {
158 case DEV_PM_QOS_RESUME_LATENCY:
159 if (WARN_ON(action != PM_QOS_REMOVE_REQ && value < 0))
160 value = 0;
161
162 ret = pm_qos_update_target(&qos->resume_latency,
163 &req->data.pnode, action, value);
164 break;
165 case DEV_PM_QOS_LATENCY_TOLERANCE:
166 ret = pm_qos_update_target(&qos->latency_tolerance,
167 &req->data.pnode, action, value);
168 if (ret) {
169 value = pm_qos_read_value(&qos->latency_tolerance);
170 req->dev->power.set_latency_tolerance(req->dev, value);
171 }
172 break;
173 case DEV_PM_QOS_MIN_FREQUENCY:
174 case DEV_PM_QOS_MAX_FREQUENCY:
175 ret = freq_qos_apply(&req->data.freq, action, value);
176 break;
177 case DEV_PM_QOS_FLAGS:
178 ret = pm_qos_update_flags(&qos->flags, &req->data.flr,
179 action, value);
180 break;
181 default:
182 ret = -EINVAL;
183 }
184
185 return ret;
186}
187
188/*
189 * dev_pm_qos_constraints_allocate
190 * @dev: device to allocate data for
191 *
192 * Called at the first call to add_request, for constraint data allocation
193 * Must be called with the dev_pm_qos_mtx mutex held
194 */
195static int dev_pm_qos_constraints_allocate(struct device *dev)
196{
197 struct dev_pm_qos *qos;
198 struct pm_qos_constraints *c;
199 struct blocking_notifier_head *n;
200
201 qos = kzalloc(sizeof(*qos), GFP_KERNEL);
202 if (!qos)
203 return -ENOMEM;
204
205 n = kcalloc(3, sizeof(*n), GFP_KERNEL);
206 if (!n) {
207 kfree(qos);
208 return -ENOMEM;
209 }
210
211 c = &qos->resume_latency;
212 plist_head_init(&c->list);
213 c->target_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;
214 c->default_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;
215 c->no_constraint_value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT;
216 c->type = PM_QOS_MIN;
217 c->notifiers = n;
218 BLOCKING_INIT_NOTIFIER_HEAD(n);
219
220 c = &qos->latency_tolerance;
221 plist_head_init(&c->list);
222 c->target_value = PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE;
223 c->default_value = PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE;
224 c->no_constraint_value = PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT;
225 c->type = PM_QOS_MIN;
226
227 freq_constraints_init(&qos->freq);
228
229 INIT_LIST_HEAD(&qos->flags.list);
230
231 spin_lock_irq(&dev->power.lock);
232 dev->power.qos = qos;
233 spin_unlock_irq(&dev->power.lock);
234
235 return 0;
236}
237
238static void __dev_pm_qos_hide_latency_limit(struct device *dev);
239static void __dev_pm_qos_hide_flags(struct device *dev);
240
241/**
242 * dev_pm_qos_constraints_destroy
243 * @dev: target device
244 *
245 * Called from the device PM subsystem on device removal under device_pm_lock().
246 */
247void dev_pm_qos_constraints_destroy(struct device *dev)
248{
249 struct dev_pm_qos *qos;
250 struct dev_pm_qos_request *req, *tmp;
251 struct pm_qos_constraints *c;
252 struct pm_qos_flags *f;
253
254 mutex_lock(&dev_pm_qos_sysfs_mtx);
255
256 /*
257 * If the device's PM QoS resume latency limit or PM QoS flags have been
258 * exposed to user space, they have to be hidden at this point.
259 */
260 pm_qos_sysfs_remove_resume_latency(dev);
261 pm_qos_sysfs_remove_flags(dev);
262
263 mutex_lock(&dev_pm_qos_mtx);
264
265 __dev_pm_qos_hide_latency_limit(dev);
266 __dev_pm_qos_hide_flags(dev);
267
268 qos = dev->power.qos;
269 if (!qos)
270 goto out;
271
272 /* Flush the constraints lists for the device. */
273 c = &qos->resume_latency;
274 plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) {
275 /*
276 * Update constraints list and call the notification
277 * callbacks if needed
278 */
279 apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
280 memset(req, 0, sizeof(*req));
281 }
282
283 c = &qos->latency_tolerance;
284 plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) {
285 apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
286 memset(req, 0, sizeof(*req));
287 }
288
289 c = &qos->freq.min_freq;
290 plist_for_each_entry_safe(req, tmp, &c->list, data.freq.pnode) {
291 apply_constraint(req, PM_QOS_REMOVE_REQ,
292 PM_QOS_MIN_FREQUENCY_DEFAULT_VALUE);
293 memset(req, 0, sizeof(*req));
294 }
295
296 c = &qos->freq.max_freq;
297 plist_for_each_entry_safe(req, tmp, &c->list, data.freq.pnode) {
298 apply_constraint(req, PM_QOS_REMOVE_REQ,
299 PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
300 memset(req, 0, sizeof(*req));
301 }
302
303 f = &qos->flags;
304 list_for_each_entry_safe(req, tmp, &f->list, data.flr.node) {
305 apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
306 memset(req, 0, sizeof(*req));
307 }
308
309 spin_lock_irq(&dev->power.lock);
310 dev->power.qos = ERR_PTR(-ENODEV);
311 spin_unlock_irq(&dev->power.lock);
312
313 kfree(qos->resume_latency.notifiers);
314 kfree(qos);
315
316 out:
317 mutex_unlock(&dev_pm_qos_mtx);
318
319 mutex_unlock(&dev_pm_qos_sysfs_mtx);
320}
321
322static bool dev_pm_qos_invalid_req_type(struct device *dev,
323 enum dev_pm_qos_req_type type)
324{
325 return type == DEV_PM_QOS_LATENCY_TOLERANCE &&
326 !dev->power.set_latency_tolerance;
327}
328
329static int __dev_pm_qos_add_request(struct device *dev,
330 struct dev_pm_qos_request *req,
331 enum dev_pm_qos_req_type type, s32 value)
332{
333 int ret = 0;
334
335 if (!dev || !req || dev_pm_qos_invalid_req_type(dev, type))
336 return -EINVAL;
337
338 if (WARN(dev_pm_qos_request_active(req),
339 "%s() called for already added request\n", __func__))
340 return -EINVAL;
341
342 if (IS_ERR(dev->power.qos))
343 ret = -ENODEV;
344 else if (!dev->power.qos)
345 ret = dev_pm_qos_constraints_allocate(dev);
346
347 trace_dev_pm_qos_add_request(dev_name(dev), type, value);
348 if (ret)
349 return ret;
350
351 req->dev = dev;
352 req->type = type;
353 if (req->type == DEV_PM_QOS_MIN_FREQUENCY)
354 ret = freq_qos_add_request(&dev->power.qos->freq,
355 &req->data.freq,
356 FREQ_QOS_MIN, value);
357 else if (req->type == DEV_PM_QOS_MAX_FREQUENCY)
358 ret = freq_qos_add_request(&dev->power.qos->freq,
359 &req->data.freq,
360 FREQ_QOS_MAX, value);
361 else
362 ret = apply_constraint(req, PM_QOS_ADD_REQ, value);
363
364 return ret;
365}
366
367/**
368 * dev_pm_qos_add_request - inserts new qos request into the list
369 * @dev: target device for the constraint
370 * @req: pointer to a preallocated handle
371 * @type: type of the request
372 * @value: defines the qos request
373 *
374 * This function inserts a new entry in the device constraints list of
375 * requested qos performance characteristics. It recomputes the aggregate
376 * QoS expectations of parameters and initializes the dev_pm_qos_request
377 * handle. Caller needs to save this handle for later use in updates and
378 * removal.
379 *
380 * Returns 1 if the aggregated constraint value has changed,
381 * 0 if the aggregated constraint value has not changed,
382 * -EINVAL in case of wrong parameters, -ENOMEM if there's not enough memory
383 * to allocate for data structures, -ENODEV if the device has just been removed
384 * from the system.
385 *
386 * Callers should ensure that the target device is not RPM_SUSPENDED before
387 * using this function for requests of type DEV_PM_QOS_FLAGS.
388 */
389int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
390 enum dev_pm_qos_req_type type, s32 value)
391{
392 int ret;
393
394 mutex_lock(&dev_pm_qos_mtx);
395 ret = __dev_pm_qos_add_request(dev, req, type, value);
396 mutex_unlock(&dev_pm_qos_mtx);
397 return ret;
398}
399EXPORT_SYMBOL_GPL(dev_pm_qos_add_request);
400
401/**
402 * __dev_pm_qos_update_request - Modify an existing device PM QoS request.
403 * @req : PM QoS request to modify.
404 * @new_value: New value to request.
405 */
406static int __dev_pm_qos_update_request(struct dev_pm_qos_request *req,
407 s32 new_value)
408{
409 s32 curr_value;
410 int ret = 0;
411
412 if (!req) /*guard against callers passing in null */
413 return -EINVAL;
414
415 if (WARN(!dev_pm_qos_request_active(req),
416 "%s() called for unknown object\n", __func__))
417 return -EINVAL;
418
419 if (IS_ERR_OR_NULL(req->dev->power.qos))
420 return -ENODEV;
421
422 switch(req->type) {
423 case DEV_PM_QOS_RESUME_LATENCY:
424 case DEV_PM_QOS_LATENCY_TOLERANCE:
425 curr_value = req->data.pnode.prio;
426 break;
427 case DEV_PM_QOS_MIN_FREQUENCY:
428 case DEV_PM_QOS_MAX_FREQUENCY:
429 curr_value = req->data.freq.pnode.prio;
430 break;
431 case DEV_PM_QOS_FLAGS:
432 curr_value = req->data.flr.flags;
433 break;
434 default:
435 return -EINVAL;
436 }
437
438 trace_dev_pm_qos_update_request(dev_name(req->dev), req->type,
439 new_value);
440 if (curr_value != new_value)
441 ret = apply_constraint(req, PM_QOS_UPDATE_REQ, new_value);
442
443 return ret;
444}
445
446/**
447 * dev_pm_qos_update_request - modifies an existing qos request
448 * @req : handle to list element holding a dev_pm_qos request to use
449 * @new_value: defines the qos request
450 *
451 * Updates an existing dev PM qos request along with updating the
452 * target value.
453 *
454 * Attempts are made to make this code callable on hot code paths.
455 *
456 * Returns 1 if the aggregated constraint value has changed,
457 * 0 if the aggregated constraint value has not changed,
458 * -EINVAL in case of wrong parameters, -ENODEV if the device has been
459 * removed from the system
460 *
461 * Callers should ensure that the target device is not RPM_SUSPENDED before
462 * using this function for requests of type DEV_PM_QOS_FLAGS.
463 */
464int dev_pm_qos_update_request(struct dev_pm_qos_request *req, s32 new_value)
465{
466 int ret;
467
468 mutex_lock(&dev_pm_qos_mtx);
469 ret = __dev_pm_qos_update_request(req, new_value);
470 mutex_unlock(&dev_pm_qos_mtx);
471 return ret;
472}
473EXPORT_SYMBOL_GPL(dev_pm_qos_update_request);
474
475static int __dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
476{
477 int ret;
478
479 if (!req) /*guard against callers passing in null */
480 return -EINVAL;
481
482 if (WARN(!dev_pm_qos_request_active(req),
483 "%s() called for unknown object\n", __func__))
484 return -EINVAL;
485
486 if (IS_ERR_OR_NULL(req->dev->power.qos))
487 return -ENODEV;
488
489 trace_dev_pm_qos_remove_request(dev_name(req->dev), req->type,
490 PM_QOS_DEFAULT_VALUE);
491 ret = apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
492 memset(req, 0, sizeof(*req));
493 return ret;
494}
495
496/**
497 * dev_pm_qos_remove_request - modifies an existing qos request
498 * @req: handle to request list element
499 *
500 * Will remove pm qos request from the list of constraints and
501 * recompute the current target value. Call this on slow code paths.
502 *
503 * Returns 1 if the aggregated constraint value has changed,
504 * 0 if the aggregated constraint value has not changed,
505 * -EINVAL in case of wrong parameters, -ENODEV if the device has been
506 * removed from the system
507 *
508 * Callers should ensure that the target device is not RPM_SUSPENDED before
509 * using this function for requests of type DEV_PM_QOS_FLAGS.
510 */
511int dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
512{
513 int ret;
514
515 mutex_lock(&dev_pm_qos_mtx);
516 ret = __dev_pm_qos_remove_request(req);
517 mutex_unlock(&dev_pm_qos_mtx);
518 return ret;
519}
520EXPORT_SYMBOL_GPL(dev_pm_qos_remove_request);
521
522/**
523 * dev_pm_qos_add_notifier - sets notification entry for changes to target value
524 * of per-device PM QoS constraints
525 *
526 * @dev: target device for the constraint
527 * @notifier: notifier block managed by caller.
528 * @type: request type.
529 *
530 * Will register the notifier into a notification chain that gets called
531 * upon changes to the target value for the device.
532 *
533 * If the device's constraints object doesn't exist when this routine is called,
534 * it will be created (or error code will be returned if that fails).
535 */
536int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier,
537 enum dev_pm_qos_req_type type)
538{
539 int ret = 0;
540
541 mutex_lock(&dev_pm_qos_mtx);
542
543 if (IS_ERR(dev->power.qos))
544 ret = -ENODEV;
545 else if (!dev->power.qos)
546 ret = dev_pm_qos_constraints_allocate(dev);
547
548 if (ret)
549 goto unlock;
550
551 switch (type) {
552 case DEV_PM_QOS_RESUME_LATENCY:
553 ret = blocking_notifier_chain_register(dev->power.qos->resume_latency.notifiers,
554 notifier);
555 break;
556 case DEV_PM_QOS_MIN_FREQUENCY:
557 ret = freq_qos_add_notifier(&dev->power.qos->freq,
558 FREQ_QOS_MIN, notifier);
559 break;
560 case DEV_PM_QOS_MAX_FREQUENCY:
561 ret = freq_qos_add_notifier(&dev->power.qos->freq,
562 FREQ_QOS_MAX, notifier);
563 break;
564 default:
565 WARN_ON(1);
566 ret = -EINVAL;
567 }
568
569unlock:
570 mutex_unlock(&dev_pm_qos_mtx);
571 return ret;
572}
573EXPORT_SYMBOL_GPL(dev_pm_qos_add_notifier);
574
575/**
576 * dev_pm_qos_remove_notifier - deletes notification for changes to target value
577 * of per-device PM QoS constraints
578 *
579 * @dev: target device for the constraint
580 * @notifier: notifier block to be removed.
581 * @type: request type.
582 *
583 * Will remove the notifier from the notification chain that gets called
584 * upon changes to the target value.
585 */
586int dev_pm_qos_remove_notifier(struct device *dev,
587 struct notifier_block *notifier,
588 enum dev_pm_qos_req_type type)
589{
590 int ret = 0;
591
592 mutex_lock(&dev_pm_qos_mtx);
593
594 /* Silently return if the constraints object is not present. */
595 if (IS_ERR_OR_NULL(dev->power.qos))
596 goto unlock;
597
598 switch (type) {
599 case DEV_PM_QOS_RESUME_LATENCY:
600 ret = blocking_notifier_chain_unregister(dev->power.qos->resume_latency.notifiers,
601 notifier);
602 break;
603 case DEV_PM_QOS_MIN_FREQUENCY:
604 ret = freq_qos_remove_notifier(&dev->power.qos->freq,
605 FREQ_QOS_MIN, notifier);
606 break;
607 case DEV_PM_QOS_MAX_FREQUENCY:
608 ret = freq_qos_remove_notifier(&dev->power.qos->freq,
609 FREQ_QOS_MAX, notifier);
610 break;
611 default:
612 WARN_ON(1);
613 ret = -EINVAL;
614 }
615
616unlock:
617 mutex_unlock(&dev_pm_qos_mtx);
618 return ret;
619}
620EXPORT_SYMBOL_GPL(dev_pm_qos_remove_notifier);
621
622/**
623 * dev_pm_qos_add_ancestor_request - Add PM QoS request for device's ancestor.
624 * @dev: Device whose ancestor to add the request for.
625 * @req: Pointer to the preallocated handle.
626 * @type: Type of the request.
627 * @value: Constraint latency value.
628 */
629int dev_pm_qos_add_ancestor_request(struct device *dev,
630 struct dev_pm_qos_request *req,
631 enum dev_pm_qos_req_type type, s32 value)
632{
633 struct device *ancestor = dev->parent;
634 int ret = -ENODEV;
635
636 switch (type) {
637 case DEV_PM_QOS_RESUME_LATENCY:
638 while (ancestor && !ancestor->power.ignore_children)
639 ancestor = ancestor->parent;
640
641 break;
642 case DEV_PM_QOS_LATENCY_TOLERANCE:
643 while (ancestor && !ancestor->power.set_latency_tolerance)
644 ancestor = ancestor->parent;
645
646 break;
647 default:
648 ancestor = NULL;
649 }
650 if (ancestor)
651 ret = dev_pm_qos_add_request(ancestor, req, type, value);
652
653 if (ret < 0)
654 req->dev = NULL;
655
656 return ret;
657}
658EXPORT_SYMBOL_GPL(dev_pm_qos_add_ancestor_request);
659
660static void __dev_pm_qos_drop_user_request(struct device *dev,
661 enum dev_pm_qos_req_type type)
662{
663 struct dev_pm_qos_request *req = NULL;
664
665 switch(type) {
666 case DEV_PM_QOS_RESUME_LATENCY:
667 req = dev->power.qos->resume_latency_req;
668 dev->power.qos->resume_latency_req = NULL;
669 break;
670 case DEV_PM_QOS_LATENCY_TOLERANCE:
671 req = dev->power.qos->latency_tolerance_req;
672 dev->power.qos->latency_tolerance_req = NULL;
673 break;
674 case DEV_PM_QOS_FLAGS:
675 req = dev->power.qos->flags_req;
676 dev->power.qos->flags_req = NULL;
677 break;
678 default:
679 WARN_ON(1);
680 return;
681 }
682 __dev_pm_qos_remove_request(req);
683 kfree(req);
684}
685
686static void dev_pm_qos_drop_user_request(struct device *dev,
687 enum dev_pm_qos_req_type type)
688{
689 mutex_lock(&dev_pm_qos_mtx);
690 __dev_pm_qos_drop_user_request(dev, type);
691 mutex_unlock(&dev_pm_qos_mtx);
692}
693
694/**
695 * dev_pm_qos_expose_latency_limit - Expose PM QoS latency limit to user space.
696 * @dev: Device whose PM QoS latency limit is to be exposed to user space.
697 * @value: Initial value of the latency limit.
698 */
699int dev_pm_qos_expose_latency_limit(struct device *dev, s32 value)
700{
701 struct dev_pm_qos_request *req;
702 int ret;
703
704 if (!device_is_registered(dev) || value < 0)
705 return -EINVAL;
706
707 req = kzalloc(sizeof(*req), GFP_KERNEL);
708 if (!req)
709 return -ENOMEM;
710
711 ret = dev_pm_qos_add_request(dev, req, DEV_PM_QOS_RESUME_LATENCY, value);
712 if (ret < 0) {
713 kfree(req);
714 return ret;
715 }
716
717 mutex_lock(&dev_pm_qos_sysfs_mtx);
718
719 mutex_lock(&dev_pm_qos_mtx);
720
721 if (IS_ERR_OR_NULL(dev->power.qos))
722 ret = -ENODEV;
723 else if (dev->power.qos->resume_latency_req)
724 ret = -EEXIST;
725
726 if (ret < 0) {
727 __dev_pm_qos_remove_request(req);
728 kfree(req);
729 mutex_unlock(&dev_pm_qos_mtx);
730 goto out;
731 }
732 dev->power.qos->resume_latency_req = req;
733
734 mutex_unlock(&dev_pm_qos_mtx);
735
736 ret = pm_qos_sysfs_add_resume_latency(dev);
737 if (ret)
738 dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_RESUME_LATENCY);
739
740 out:
741 mutex_unlock(&dev_pm_qos_sysfs_mtx);
742 return ret;
743}
744EXPORT_SYMBOL_GPL(dev_pm_qos_expose_latency_limit);
745
746static void __dev_pm_qos_hide_latency_limit(struct device *dev)
747{
748 if (!IS_ERR_OR_NULL(dev->power.qos) && dev->power.qos->resume_latency_req)
749 __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_RESUME_LATENCY);
750}
751
752/**
753 * dev_pm_qos_hide_latency_limit - Hide PM QoS latency limit from user space.
754 * @dev: Device whose PM QoS latency limit is to be hidden from user space.
755 */
756void dev_pm_qos_hide_latency_limit(struct device *dev)
757{
758 mutex_lock(&dev_pm_qos_sysfs_mtx);
759
760 pm_qos_sysfs_remove_resume_latency(dev);
761
762 mutex_lock(&dev_pm_qos_mtx);
763 __dev_pm_qos_hide_latency_limit(dev);
764 mutex_unlock(&dev_pm_qos_mtx);
765
766 mutex_unlock(&dev_pm_qos_sysfs_mtx);
767}
768EXPORT_SYMBOL_GPL(dev_pm_qos_hide_latency_limit);
769
770/**
771 * dev_pm_qos_expose_flags - Expose PM QoS flags of a device to user space.
772 * @dev: Device whose PM QoS flags are to be exposed to user space.
773 * @val: Initial values of the flags.
774 */
775int dev_pm_qos_expose_flags(struct device *dev, s32 val)
776{
777 struct dev_pm_qos_request *req;
778 int ret;
779
780 if (!device_is_registered(dev))
781 return -EINVAL;
782
783 req = kzalloc(sizeof(*req), GFP_KERNEL);
784 if (!req)
785 return -ENOMEM;
786
787 ret = dev_pm_qos_add_request(dev, req, DEV_PM_QOS_FLAGS, val);
788 if (ret < 0) {
789 kfree(req);
790 return ret;
791 }
792
793 pm_runtime_get_sync(dev);
794 mutex_lock(&dev_pm_qos_sysfs_mtx);
795
796 mutex_lock(&dev_pm_qos_mtx);
797
798 if (IS_ERR_OR_NULL(dev->power.qos))
799 ret = -ENODEV;
800 else if (dev->power.qos->flags_req)
801 ret = -EEXIST;
802
803 if (ret < 0) {
804 __dev_pm_qos_remove_request(req);
805 kfree(req);
806 mutex_unlock(&dev_pm_qos_mtx);
807 goto out;
808 }
809 dev->power.qos->flags_req = req;
810
811 mutex_unlock(&dev_pm_qos_mtx);
812
813 ret = pm_qos_sysfs_add_flags(dev);
814 if (ret)
815 dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_FLAGS);
816
817 out:
818 mutex_unlock(&dev_pm_qos_sysfs_mtx);
819 pm_runtime_put(dev);
820 return ret;
821}
822EXPORT_SYMBOL_GPL(dev_pm_qos_expose_flags);
823
824static void __dev_pm_qos_hide_flags(struct device *dev)
825{
826 if (!IS_ERR_OR_NULL(dev->power.qos) && dev->power.qos->flags_req)
827 __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_FLAGS);
828}
829
830/**
831 * dev_pm_qos_hide_flags - Hide PM QoS flags of a device from user space.
832 * @dev: Device whose PM QoS flags are to be hidden from user space.
833 */
834void dev_pm_qos_hide_flags(struct device *dev)
835{
836 pm_runtime_get_sync(dev);
837 mutex_lock(&dev_pm_qos_sysfs_mtx);
838
839 pm_qos_sysfs_remove_flags(dev);
840
841 mutex_lock(&dev_pm_qos_mtx);
842 __dev_pm_qos_hide_flags(dev);
843 mutex_unlock(&dev_pm_qos_mtx);
844
845 mutex_unlock(&dev_pm_qos_sysfs_mtx);
846 pm_runtime_put(dev);
847}
848EXPORT_SYMBOL_GPL(dev_pm_qos_hide_flags);
849
850/**
851 * dev_pm_qos_update_flags - Update PM QoS flags request owned by user space.
852 * @dev: Device to update the PM QoS flags request for.
853 * @mask: Flags to set/clear.
854 * @set: Whether to set or clear the flags (true means set).
855 */
856int dev_pm_qos_update_flags(struct device *dev, s32 mask, bool set)
857{
858 s32 value;
859 int ret;
860
861 pm_runtime_get_sync(dev);
862 mutex_lock(&dev_pm_qos_mtx);
863
864 if (IS_ERR_OR_NULL(dev->power.qos) || !dev->power.qos->flags_req) {
865 ret = -EINVAL;
866 goto out;
867 }
868
869 value = dev_pm_qos_requested_flags(dev);
870 if (set)
871 value |= mask;
872 else
873 value &= ~mask;
874
875 ret = __dev_pm_qos_update_request(dev->power.qos->flags_req, value);
876
877 out:
878 mutex_unlock(&dev_pm_qos_mtx);
879 pm_runtime_put(dev);
880 return ret;
881}
882
883/**
884 * dev_pm_qos_get_user_latency_tolerance - Get user space latency tolerance.
885 * @dev: Device to obtain the user space latency tolerance for.
886 */
887s32 dev_pm_qos_get_user_latency_tolerance(struct device *dev)
888{
889 s32 ret;
890
891 mutex_lock(&dev_pm_qos_mtx);
892 ret = IS_ERR_OR_NULL(dev->power.qos)
893 || !dev->power.qos->latency_tolerance_req ?
894 PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT :
895 dev->power.qos->latency_tolerance_req->data.pnode.prio;
896 mutex_unlock(&dev_pm_qos_mtx);
897 return ret;
898}
899
900/**
901 * dev_pm_qos_update_user_latency_tolerance - Update user space latency tolerance.
902 * @dev: Device to update the user space latency tolerance for.
903 * @val: New user space latency tolerance for @dev (negative values disable).
904 */
905int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
906{
907 int ret;
908
909 mutex_lock(&dev_pm_qos_mtx);
910
911 if (IS_ERR_OR_NULL(dev->power.qos)
912 || !dev->power.qos->latency_tolerance_req) {
913 struct dev_pm_qos_request *req;
914
915 if (val < 0) {
916 if (val == PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT)
917 ret = 0;
918 else
919 ret = -EINVAL;
920 goto out;
921 }
922 req = kzalloc(sizeof(*req), GFP_KERNEL);
923 if (!req) {
924 ret = -ENOMEM;
925 goto out;
926 }
927 ret = __dev_pm_qos_add_request(dev, req, DEV_PM_QOS_LATENCY_TOLERANCE, val);
928 if (ret < 0) {
929 kfree(req);
930 goto out;
931 }
932 dev->power.qos->latency_tolerance_req = req;
933 } else {
934 if (val < 0) {
935 __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_LATENCY_TOLERANCE);
936 ret = 0;
937 } else {
938 ret = __dev_pm_qos_update_request(dev->power.qos->latency_tolerance_req, val);
939 }
940 }
941
942 out:
943 mutex_unlock(&dev_pm_qos_mtx);
944 return ret;
945}
946EXPORT_SYMBOL_GPL(dev_pm_qos_update_user_latency_tolerance);
947
948/**
949 * dev_pm_qos_expose_latency_tolerance - Expose latency tolerance to userspace
950 * @dev: Device whose latency tolerance to expose
951 */
952int dev_pm_qos_expose_latency_tolerance(struct device *dev)
953{
954 int ret;
955
956 if (!dev->power.set_latency_tolerance)
957 return -EINVAL;
958
959 mutex_lock(&dev_pm_qos_sysfs_mtx);
960 ret = pm_qos_sysfs_add_latency_tolerance(dev);
961 mutex_unlock(&dev_pm_qos_sysfs_mtx);
962
963 return ret;
964}
965EXPORT_SYMBOL_GPL(dev_pm_qos_expose_latency_tolerance);
966
967/**
968 * dev_pm_qos_hide_latency_tolerance - Hide latency tolerance from userspace
969 * @dev: Device whose latency tolerance to hide
970 */
971void dev_pm_qos_hide_latency_tolerance(struct device *dev)
972{
973 mutex_lock(&dev_pm_qos_sysfs_mtx);
974 pm_qos_sysfs_remove_latency_tolerance(dev);
975 mutex_unlock(&dev_pm_qos_sysfs_mtx);
976
977 /* Remove the request from user space now */
978 pm_runtime_get_sync(dev);
979 dev_pm_qos_update_user_latency_tolerance(dev,
980 PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT);
981 pm_runtime_put(dev);
982}
983EXPORT_SYMBOL_GPL(dev_pm_qos_hide_latency_tolerance);