Commit | Line | Data |
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91ff4cb8 JP |
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. | |
b66213cd JP |
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. | |
91ff4cb8 JP |
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. | |
91ff4cb8 JP |
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> | |
1b6bc32f | 42 | #include <linux/export.h> |
91ff4cb8 | 43 | |
85dc0b8a | 44 | #include "power.h" |
91ff4cb8 JP |
45 | |
46 | static DEFINE_MUTEX(dev_pm_qos_mtx); | |
1a9a9152 | 47 | |
b66213cd JP |
48 | static BLOCKING_NOTIFIER_HEAD(dev_pm_notifiers); |
49 | ||
ae0fb4b7 RW |
50 | /** |
51 | * __dev_pm_qos_flags - Check PM QoS flags for a given device. | |
52 | * @dev: Device to check the PM QoS flags for. | |
53 | * @mask: Flags to check against. | |
54 | * | |
55 | * This routine must be called with dev->power.lock held. | |
56 | */ | |
57 | enum pm_qos_flags_status __dev_pm_qos_flags(struct device *dev, s32 mask) | |
58 | { | |
59 | struct dev_pm_qos *qos = dev->power.qos; | |
60 | struct pm_qos_flags *pqf; | |
61 | s32 val; | |
62 | ||
63 | if (!qos) | |
64 | return PM_QOS_FLAGS_UNDEFINED; | |
65 | ||
66 | pqf = &qos->flags; | |
67 | if (list_empty(&pqf->list)) | |
68 | return PM_QOS_FLAGS_UNDEFINED; | |
69 | ||
70 | val = pqf->effective_flags & mask; | |
71 | if (val) | |
72 | return (val == mask) ? PM_QOS_FLAGS_ALL : PM_QOS_FLAGS_SOME; | |
73 | ||
74 | return PM_QOS_FLAGS_NONE; | |
75 | } | |
76 | ||
77 | /** | |
78 | * dev_pm_qos_flags - Check PM QoS flags for a given device (locked). | |
79 | * @dev: Device to check the PM QoS flags for. | |
80 | * @mask: Flags to check against. | |
81 | */ | |
82 | enum pm_qos_flags_status dev_pm_qos_flags(struct device *dev, s32 mask) | |
83 | { | |
84 | unsigned long irqflags; | |
85 | enum pm_qos_flags_status ret; | |
86 | ||
87 | spin_lock_irqsave(&dev->power.lock, irqflags); | |
88 | ret = __dev_pm_qos_flags(dev, mask); | |
89 | spin_unlock_irqrestore(&dev->power.lock, irqflags); | |
90 | ||
91 | return ret; | |
92 | } | |
93 | ||
1a9a9152 | 94 | /** |
00dc9ad1 RW |
95 | * __dev_pm_qos_read_value - Get PM QoS constraint for a given device. |
96 | * @dev: Device to get the PM QoS constraint value for. | |
97 | * | |
98 | * This routine must be called with dev->power.lock held. | |
99 | */ | |
100 | s32 __dev_pm_qos_read_value(struct device *dev) | |
101 | { | |
5f986c59 | 102 | return dev->power.qos ? pm_qos_read_value(&dev->power.qos->latency) : 0; |
00dc9ad1 RW |
103 | } |
104 | ||
105 | /** | |
106 | * dev_pm_qos_read_value - Get PM QoS constraint for a given device (locked). | |
1a9a9152 RW |
107 | * @dev: Device to get the PM QoS constraint value for. |
108 | */ | |
109 | s32 dev_pm_qos_read_value(struct device *dev) | |
110 | { | |
1a9a9152 | 111 | unsigned long flags; |
00dc9ad1 | 112 | s32 ret; |
1a9a9152 RW |
113 | |
114 | spin_lock_irqsave(&dev->power.lock, flags); | |
00dc9ad1 | 115 | ret = __dev_pm_qos_read_value(dev); |
1a9a9152 RW |
116 | spin_unlock_irqrestore(&dev->power.lock, flags); |
117 | ||
118 | return ret; | |
119 | } | |
120 | ||
ae0fb4b7 RW |
121 | /** |
122 | * apply_constraint - Add/modify/remove device PM QoS request. | |
123 | * @req: Constraint request to apply | |
124 | * @action: Action to perform (add/update/remove). | |
125 | * @value: Value to assign to the QoS request. | |
b66213cd JP |
126 | * |
127 | * Internal function to update the constraints list using the PM QoS core | |
128 | * code and if needed call the per-device and the global notification | |
129 | * callbacks | |
130 | */ | |
131 | static int apply_constraint(struct dev_pm_qos_request *req, | |
ae0fb4b7 | 132 | enum pm_qos_req_action action, s32 value) |
b66213cd | 133 | { |
ae0fb4b7 RW |
134 | struct dev_pm_qos *qos = req->dev->power.qos; |
135 | int ret; | |
b66213cd | 136 | |
ae0fb4b7 RW |
137 | switch(req->type) { |
138 | case DEV_PM_QOS_LATENCY: | |
139 | ret = pm_qos_update_target(&qos->latency, &req->data.pnode, | |
140 | action, value); | |
141 | if (ret) { | |
142 | value = pm_qos_read_value(&qos->latency); | |
143 | blocking_notifier_call_chain(&dev_pm_notifiers, | |
144 | (unsigned long)value, | |
145 | req); | |
146 | } | |
147 | break; | |
148 | case DEV_PM_QOS_FLAGS: | |
149 | ret = pm_qos_update_flags(&qos->flags, &req->data.flr, | |
150 | action, value); | |
151 | break; | |
152 | default: | |
153 | ret = -EINVAL; | |
b66213cd JP |
154 | } |
155 | ||
156 | return ret; | |
157 | } | |
91ff4cb8 JP |
158 | |
159 | /* | |
160 | * dev_pm_qos_constraints_allocate | |
161 | * @dev: device to allocate data for | |
162 | * | |
163 | * Called at the first call to add_request, for constraint data allocation | |
164 | * Must be called with the dev_pm_qos_mtx mutex held | |
165 | */ | |
166 | static int dev_pm_qos_constraints_allocate(struct device *dev) | |
167 | { | |
5f986c59 | 168 | struct dev_pm_qos *qos; |
91ff4cb8 JP |
169 | struct pm_qos_constraints *c; |
170 | struct blocking_notifier_head *n; | |
171 | ||
5f986c59 RW |
172 | qos = kzalloc(sizeof(*qos), GFP_KERNEL); |
173 | if (!qos) | |
91ff4cb8 JP |
174 | return -ENOMEM; |
175 | ||
176 | n = kzalloc(sizeof(*n), GFP_KERNEL); | |
177 | if (!n) { | |
5f986c59 | 178 | kfree(qos); |
91ff4cb8 JP |
179 | return -ENOMEM; |
180 | } | |
181 | BLOCKING_INIT_NOTIFIER_HEAD(n); | |
182 | ||
5f986c59 | 183 | c = &qos->latency; |
1a9a9152 RW |
184 | plist_head_init(&c->list); |
185 | c->target_value = PM_QOS_DEV_LAT_DEFAULT_VALUE; | |
186 | c->default_value = PM_QOS_DEV_LAT_DEFAULT_VALUE; | |
187 | c->type = PM_QOS_MIN; | |
188 | c->notifiers = n; | |
189 | ||
ae0fb4b7 RW |
190 | INIT_LIST_HEAD(&qos->flags.list); |
191 | ||
1a9a9152 | 192 | spin_lock_irq(&dev->power.lock); |
5f986c59 | 193 | dev->power.qos = qos; |
1a9a9152 | 194 | spin_unlock_irq(&dev->power.lock); |
91ff4cb8 JP |
195 | |
196 | return 0; | |
197 | } | |
198 | ||
199 | /** | |
1a9a9152 | 200 | * dev_pm_qos_constraints_init - Initalize device's PM QoS constraints pointer. |
91ff4cb8 JP |
201 | * @dev: target device |
202 | * | |
1a9a9152 RW |
203 | * Called from the device PM subsystem during device insertion under |
204 | * device_pm_lock(). | |
91ff4cb8 JP |
205 | */ |
206 | void dev_pm_qos_constraints_init(struct device *dev) | |
207 | { | |
208 | mutex_lock(&dev_pm_qos_mtx); | |
5f986c59 | 209 | dev->power.qos = NULL; |
1a9a9152 | 210 | dev->power.power_state = PMSG_ON; |
91ff4cb8 JP |
211 | mutex_unlock(&dev_pm_qos_mtx); |
212 | } | |
213 | ||
214 | /** | |
215 | * dev_pm_qos_constraints_destroy | |
216 | * @dev: target device | |
217 | * | |
1a9a9152 | 218 | * Called from the device PM subsystem on device removal under device_pm_lock(). |
91ff4cb8 JP |
219 | */ |
220 | void dev_pm_qos_constraints_destroy(struct device *dev) | |
221 | { | |
5f986c59 | 222 | struct dev_pm_qos *qos; |
91ff4cb8 | 223 | struct dev_pm_qos_request *req, *tmp; |
1a9a9152 | 224 | struct pm_qos_constraints *c; |
91ff4cb8 | 225 | |
85dc0b8a RW |
226 | /* |
227 | * If the device's PM QoS resume latency limit has been exposed to user | |
228 | * space, it has to be hidden at this point. | |
229 | */ | |
230 | dev_pm_qos_hide_latency_limit(dev); | |
231 | ||
91ff4cb8 JP |
232 | mutex_lock(&dev_pm_qos_mtx); |
233 | ||
1a9a9152 | 234 | dev->power.power_state = PMSG_INVALID; |
5f986c59 RW |
235 | qos = dev->power.qos; |
236 | if (!qos) | |
1a9a9152 | 237 | goto out; |
91ff4cb8 | 238 | |
5f986c59 | 239 | c = &qos->latency; |
1a9a9152 | 240 | /* Flush the constraints list for the device */ |
021c870b | 241 | plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) { |
1a9a9152 RW |
242 | /* |
243 | * Update constraints list and call the notification | |
244 | * callbacks if needed | |
245 | */ | |
246 | apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE); | |
247 | memset(req, 0, sizeof(*req)); | |
91ff4cb8 | 248 | } |
91ff4cb8 | 249 | |
1a9a9152 | 250 | spin_lock_irq(&dev->power.lock); |
5f986c59 | 251 | dev->power.qos = NULL; |
1a9a9152 RW |
252 | spin_unlock_irq(&dev->power.lock); |
253 | ||
254 | kfree(c->notifiers); | |
255 | kfree(c); | |
256 | ||
257 | out: | |
91ff4cb8 JP |
258 | mutex_unlock(&dev_pm_qos_mtx); |
259 | } | |
260 | ||
261 | /** | |
262 | * dev_pm_qos_add_request - inserts new qos request into the list | |
263 | * @dev: target device for the constraint | |
264 | * @req: pointer to a preallocated handle | |
ae0fb4b7 | 265 | * @type: type of the request |
91ff4cb8 JP |
266 | * @value: defines the qos request |
267 | * | |
268 | * This function inserts a new entry in the device constraints list of | |
269 | * requested qos performance characteristics. It recomputes the aggregate | |
270 | * QoS expectations of parameters and initializes the dev_pm_qos_request | |
271 | * handle. Caller needs to save this handle for later use in updates and | |
272 | * removal. | |
273 | * | |
274 | * Returns 1 if the aggregated constraint value has changed, | |
275 | * 0 if the aggregated constraint value has not changed, | |
1a9a9152 RW |
276 | * -EINVAL in case of wrong parameters, -ENOMEM if there's not enough memory |
277 | * to allocate for data structures, -ENODEV if the device has just been removed | |
278 | * from the system. | |
91ff4cb8 JP |
279 | */ |
280 | int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req, | |
ae0fb4b7 | 281 | enum dev_pm_qos_req_type type, s32 value) |
91ff4cb8 JP |
282 | { |
283 | int ret = 0; | |
284 | ||
285 | if (!dev || !req) /*guard against callers passing in null */ | |
286 | return -EINVAL; | |
287 | ||
af4c720e GL |
288 | if (WARN(dev_pm_qos_request_active(req), |
289 | "%s() called for already added request\n", __func__)) | |
91ff4cb8 | 290 | return -EINVAL; |
91ff4cb8 | 291 | |
91ff4cb8 JP |
292 | req->dev = dev; |
293 | ||
1a9a9152 | 294 | mutex_lock(&dev_pm_qos_mtx); |
91ff4cb8 | 295 | |
5f986c59 | 296 | if (!dev->power.qos) { |
1a9a9152 RW |
297 | if (dev->power.power_state.event == PM_EVENT_INVALID) { |
298 | /* The device has been removed from the system. */ | |
299 | req->dev = NULL; | |
300 | ret = -ENODEV; | |
301 | goto out; | |
302 | } else { | |
303 | /* | |
304 | * Allocate the constraints data on the first call to | |
305 | * add_request, i.e. only if the data is not already | |
306 | * allocated and if the device has not been removed. | |
307 | */ | |
308 | ret = dev_pm_qos_constraints_allocate(dev); | |
309 | } | |
310 | } | |
91ff4cb8 | 311 | |
ae0fb4b7 RW |
312 | if (!ret) { |
313 | req->type = type; | |
b66213cd | 314 | ret = apply_constraint(req, PM_QOS_ADD_REQ, value); |
ae0fb4b7 | 315 | } |
91ff4cb8 | 316 | |
1a9a9152 | 317 | out: |
91ff4cb8 | 318 | mutex_unlock(&dev_pm_qos_mtx); |
1a9a9152 | 319 | |
91ff4cb8 JP |
320 | return ret; |
321 | } | |
322 | EXPORT_SYMBOL_GPL(dev_pm_qos_add_request); | |
323 | ||
324 | /** | |
325 | * dev_pm_qos_update_request - modifies an existing qos request | |
326 | * @req : handle to list element holding a dev_pm_qos request to use | |
327 | * @new_value: defines the qos request | |
328 | * | |
329 | * Updates an existing dev PM qos request along with updating the | |
330 | * target value. | |
331 | * | |
332 | * Attempts are made to make this code callable on hot code paths. | |
333 | * | |
334 | * Returns 1 if the aggregated constraint value has changed, | |
335 | * 0 if the aggregated constraint value has not changed, | |
336 | * -EINVAL in case of wrong parameters, -ENODEV if the device has been | |
337 | * removed from the system | |
338 | */ | |
339 | int dev_pm_qos_update_request(struct dev_pm_qos_request *req, | |
340 | s32 new_value) | |
341 | { | |
ae0fb4b7 | 342 | s32 curr_value; |
91ff4cb8 JP |
343 | int ret = 0; |
344 | ||
345 | if (!req) /*guard against callers passing in null */ | |
346 | return -EINVAL; | |
347 | ||
af4c720e GL |
348 | if (WARN(!dev_pm_qos_request_active(req), |
349 | "%s() called for unknown object\n", __func__)) | |
91ff4cb8 | 350 | return -EINVAL; |
91ff4cb8 JP |
351 | |
352 | mutex_lock(&dev_pm_qos_mtx); | |
353 | ||
ae0fb4b7 | 354 | if (!req->dev->power.qos) { |
91ff4cb8 | 355 | ret = -ENODEV; |
ae0fb4b7 | 356 | goto out; |
91ff4cb8 JP |
357 | } |
358 | ||
ae0fb4b7 RW |
359 | switch(req->type) { |
360 | case DEV_PM_QOS_LATENCY: | |
361 | curr_value = req->data.pnode.prio; | |
362 | break; | |
363 | case DEV_PM_QOS_FLAGS: | |
364 | curr_value = req->data.flr.flags; | |
365 | break; | |
366 | default: | |
367 | ret = -EINVAL; | |
368 | goto out; | |
369 | } | |
370 | ||
371 | if (curr_value != new_value) | |
372 | ret = apply_constraint(req, PM_QOS_UPDATE_REQ, new_value); | |
373 | ||
374 | out: | |
91ff4cb8 JP |
375 | mutex_unlock(&dev_pm_qos_mtx); |
376 | return ret; | |
377 | } | |
378 | EXPORT_SYMBOL_GPL(dev_pm_qos_update_request); | |
379 | ||
380 | /** | |
381 | * dev_pm_qos_remove_request - modifies an existing qos request | |
382 | * @req: handle to request list element | |
383 | * | |
384 | * Will remove pm qos request from the list of constraints and | |
385 | * recompute the current target value. Call this on slow code paths. | |
386 | * | |
387 | * Returns 1 if the aggregated constraint value has changed, | |
388 | * 0 if the aggregated constraint value has not changed, | |
389 | * -EINVAL in case of wrong parameters, -ENODEV if the device has been | |
390 | * removed from the system | |
391 | */ | |
392 | int dev_pm_qos_remove_request(struct dev_pm_qos_request *req) | |
393 | { | |
394 | int ret = 0; | |
395 | ||
396 | if (!req) /*guard against callers passing in null */ | |
397 | return -EINVAL; | |
398 | ||
af4c720e GL |
399 | if (WARN(!dev_pm_qos_request_active(req), |
400 | "%s() called for unknown object\n", __func__)) | |
91ff4cb8 | 401 | return -EINVAL; |
91ff4cb8 JP |
402 | |
403 | mutex_lock(&dev_pm_qos_mtx); | |
404 | ||
5f986c59 | 405 | if (req->dev->power.qos) { |
b66213cd JP |
406 | ret = apply_constraint(req, PM_QOS_REMOVE_REQ, |
407 | PM_QOS_DEFAULT_VALUE); | |
91ff4cb8 JP |
408 | memset(req, 0, sizeof(*req)); |
409 | } else { | |
410 | /* Return if the device has been removed */ | |
411 | ret = -ENODEV; | |
412 | } | |
413 | ||
414 | mutex_unlock(&dev_pm_qos_mtx); | |
415 | return ret; | |
416 | } | |
417 | EXPORT_SYMBOL_GPL(dev_pm_qos_remove_request); | |
418 | ||
419 | /** | |
420 | * dev_pm_qos_add_notifier - sets notification entry for changes to target value | |
421 | * of per-device PM QoS constraints | |
422 | * | |
423 | * @dev: target device for the constraint | |
424 | * @notifier: notifier block managed by caller. | |
425 | * | |
426 | * Will register the notifier into a notification chain that gets called | |
427 | * upon changes to the target value for the device. | |
23e0fc5a RW |
428 | * |
429 | * If the device's constraints object doesn't exist when this routine is called, | |
430 | * it will be created (or error code will be returned if that fails). | |
91ff4cb8 JP |
431 | */ |
432 | int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier) | |
433 | { | |
23e0fc5a | 434 | int ret = 0; |
91ff4cb8 JP |
435 | |
436 | mutex_lock(&dev_pm_qos_mtx); | |
437 | ||
5f986c59 | 438 | if (!dev->power.qos) |
23e0fc5a RW |
439 | ret = dev->power.power_state.event != PM_EVENT_INVALID ? |
440 | dev_pm_qos_constraints_allocate(dev) : -ENODEV; | |
441 | ||
442 | if (!ret) | |
443 | ret = blocking_notifier_chain_register( | |
5f986c59 | 444 | dev->power.qos->latency.notifiers, notifier); |
91ff4cb8 | 445 | |
91ff4cb8 | 446 | mutex_unlock(&dev_pm_qos_mtx); |
23e0fc5a | 447 | return ret; |
91ff4cb8 JP |
448 | } |
449 | EXPORT_SYMBOL_GPL(dev_pm_qos_add_notifier); | |
450 | ||
451 | /** | |
452 | * dev_pm_qos_remove_notifier - deletes notification for changes to target value | |
453 | * of per-device PM QoS constraints | |
454 | * | |
455 | * @dev: target device for the constraint | |
456 | * @notifier: notifier block to be removed. | |
457 | * | |
458 | * Will remove the notifier from the notification chain that gets called | |
459 | * upon changes to the target value. | |
460 | */ | |
461 | int dev_pm_qos_remove_notifier(struct device *dev, | |
462 | struct notifier_block *notifier) | |
463 | { | |
464 | int retval = 0; | |
465 | ||
466 | mutex_lock(&dev_pm_qos_mtx); | |
467 | ||
1a9a9152 | 468 | /* Silently return if the constraints object is not present. */ |
5f986c59 | 469 | if (dev->power.qos) |
1a9a9152 | 470 | retval = blocking_notifier_chain_unregister( |
5f986c59 | 471 | dev->power.qos->latency.notifiers, |
1a9a9152 | 472 | notifier); |
91ff4cb8 | 473 | |
91ff4cb8 JP |
474 | mutex_unlock(&dev_pm_qos_mtx); |
475 | return retval; | |
476 | } | |
477 | EXPORT_SYMBOL_GPL(dev_pm_qos_remove_notifier); | |
b66213cd JP |
478 | |
479 | /** | |
480 | * dev_pm_qos_add_global_notifier - sets notification entry for changes to | |
481 | * target value of the PM QoS constraints for any device | |
482 | * | |
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 any device. | |
487 | */ | |
488 | int dev_pm_qos_add_global_notifier(struct notifier_block *notifier) | |
489 | { | |
490 | return blocking_notifier_chain_register(&dev_pm_notifiers, notifier); | |
491 | } | |
492 | EXPORT_SYMBOL_GPL(dev_pm_qos_add_global_notifier); | |
493 | ||
494 | /** | |
495 | * dev_pm_qos_remove_global_notifier - deletes notification for changes to | |
496 | * target value of PM QoS constraints for any device | |
497 | * | |
498 | * @notifier: notifier block to be removed. | |
499 | * | |
500 | * Will remove the notifier from the notification chain that gets called | |
501 | * upon changes to the target value for any device. | |
502 | */ | |
503 | int dev_pm_qos_remove_global_notifier(struct notifier_block *notifier) | |
504 | { | |
505 | return blocking_notifier_chain_unregister(&dev_pm_notifiers, notifier); | |
506 | } | |
507 | EXPORT_SYMBOL_GPL(dev_pm_qos_remove_global_notifier); | |
40a5f8be RW |
508 | |
509 | /** | |
510 | * dev_pm_qos_add_ancestor_request - Add PM QoS request for device's ancestor. | |
511 | * @dev: Device whose ancestor to add the request for. | |
512 | * @req: Pointer to the preallocated handle. | |
513 | * @value: Constraint latency value. | |
514 | */ | |
515 | int dev_pm_qos_add_ancestor_request(struct device *dev, | |
516 | struct dev_pm_qos_request *req, s32 value) | |
517 | { | |
518 | struct device *ancestor = dev->parent; | |
519 | int error = -ENODEV; | |
520 | ||
521 | while (ancestor && !ancestor->power.ignore_children) | |
522 | ancestor = ancestor->parent; | |
523 | ||
524 | if (ancestor) | |
ae0fb4b7 RW |
525 | error = dev_pm_qos_add_request(ancestor, req, |
526 | DEV_PM_QOS_LATENCY, value); | |
40a5f8be RW |
527 | |
528 | if (error) | |
529 | req->dev = NULL; | |
530 | ||
531 | return error; | |
532 | } | |
533 | EXPORT_SYMBOL_GPL(dev_pm_qos_add_ancestor_request); | |
85dc0b8a RW |
534 | |
535 | #ifdef CONFIG_PM_RUNTIME | |
536 | static void __dev_pm_qos_drop_user_request(struct device *dev) | |
537 | { | |
538 | dev_pm_qos_remove_request(dev->power.pq_req); | |
ad0446eb | 539 | dev->power.pq_req = NULL; |
85dc0b8a RW |
540 | } |
541 | ||
542 | /** | |
543 | * dev_pm_qos_expose_latency_limit - Expose PM QoS latency limit to user space. | |
544 | * @dev: Device whose PM QoS latency limit is to be exposed to user space. | |
545 | * @value: Initial value of the latency limit. | |
546 | */ | |
547 | int dev_pm_qos_expose_latency_limit(struct device *dev, s32 value) | |
548 | { | |
549 | struct dev_pm_qos_request *req; | |
550 | int ret; | |
551 | ||
552 | if (!device_is_registered(dev) || value < 0) | |
553 | return -EINVAL; | |
554 | ||
555 | if (dev->power.pq_req) | |
556 | return -EEXIST; | |
557 | ||
558 | req = kzalloc(sizeof(*req), GFP_KERNEL); | |
559 | if (!req) | |
560 | return -ENOMEM; | |
561 | ||
ae0fb4b7 | 562 | ret = dev_pm_qos_add_request(dev, req, DEV_PM_QOS_LATENCY, value); |
85dc0b8a RW |
563 | if (ret < 0) |
564 | return ret; | |
565 | ||
566 | dev->power.pq_req = req; | |
567 | ret = pm_qos_sysfs_add(dev); | |
568 | if (ret) | |
569 | __dev_pm_qos_drop_user_request(dev); | |
570 | ||
571 | return ret; | |
572 | } | |
573 | EXPORT_SYMBOL_GPL(dev_pm_qos_expose_latency_limit); | |
574 | ||
575 | /** | |
576 | * dev_pm_qos_hide_latency_limit - Hide PM QoS latency limit from user space. | |
577 | * @dev: Device whose PM QoS latency limit is to be hidden from user space. | |
578 | */ | |
579 | void dev_pm_qos_hide_latency_limit(struct device *dev) | |
580 | { | |
581 | if (dev->power.pq_req) { | |
582 | pm_qos_sysfs_remove(dev); | |
583 | __dev_pm_qos_drop_user_request(dev); | |
584 | } | |
585 | } | |
586 | EXPORT_SYMBOL_GPL(dev_pm_qos_hide_latency_limit); | |
587 | #endif /* CONFIG_PM_RUNTIME */ |