1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Power Management Quality of Service (PM QoS) support base. |
4 | * |
5 | * Copyright (C) 2020 Intel Corporation |
6 | * |
7 | * Authors: |
8 | * Mark Gross <mgross@linux.intel.com> |
9 | * Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
10 | * |
11 | * Provided here is an interface for specifying PM QoS dependencies. It allows |
12 | * entities depending on QoS constraints to register their requests which are |
13 | * aggregated as appropriate to produce effective constraints (target values) |
14 | * that can be monitored by entities needing to respect them, either by polling |
15 | * or through a built-in notification mechanism. |
16 | * |
17 | * In addition to the basic functionality, more specific interfaces for managing |
18 | * global CPU latency QoS requests and frequency QoS requests are provided. |
19 | */ |
20 | |
21 | /*#define DEBUG*/ |
22 | |
23 | #include <linux/pm_qos.h> |
24 | #include <linux/sched.h> |
25 | #include <linux/spinlock.h> |
26 | #include <linux/slab.h> |
27 | #include <linux/time.h> |
28 | #include <linux/fs.h> |
29 | #include <linux/device.h> |
30 | #include <linux/miscdevice.h> |
31 | #include <linux/string.h> |
32 | #include <linux/platform_device.h> |
33 | #include <linux/init.h> |
34 | #include <linux/kernel.h> |
35 | #include <linux/debugfs.h> |
36 | #include <linux/seq_file.h> |
37 | |
38 | #include <linux/uaccess.h> |
39 | #include <linux/export.h> |
40 | #include <trace/events/power.h> |
41 | |
42 | /* |
43 | * locking rule: all changes to constraints or notifiers lists |
44 | * or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock |
45 | * held, taken with _irqsave. One lock to rule them all |
46 | */ |
47 | static DEFINE_SPINLOCK(pm_qos_lock); |
48 | |
49 | /** |
50 | * pm_qos_read_value - Return the current effective constraint value. |
51 | * @c: List of PM QoS constraint requests. |
52 | */ |
53 | s32 pm_qos_read_value(struct pm_qos_constraints *c) |
54 | { |
55 | return READ_ONCE(c->target_value); |
56 | } |
57 | |
58 | static int pm_qos_get_value(struct pm_qos_constraints *c) |
59 | { |
60 | if (plist_head_empty(head: &c->list)) |
61 | return c->no_constraint_value; |
62 | |
63 | switch (c->type) { |
64 | case PM_QOS_MIN: |
65 | return plist_first(head: &c->list)->prio; |
66 | |
67 | case PM_QOS_MAX: |
68 | return plist_last(head: &c->list)->prio; |
69 | |
70 | default: |
71 | WARN(1, "Unknown PM QoS type in %s\n" , __func__); |
72 | return PM_QOS_DEFAULT_VALUE; |
73 | } |
74 | } |
75 | |
76 | static void pm_qos_set_value(struct pm_qos_constraints *c, s32 value) |
77 | { |
78 | WRITE_ONCE(c->target_value, value); |
79 | } |
80 | |
81 | /** |
82 | * pm_qos_update_target - Update a list of PM QoS constraint requests. |
83 | * @c: List of PM QoS requests. |
84 | * @node: Target list entry. |
85 | * @action: Action to carry out (add, update or remove). |
86 | * @value: New request value for the target list entry. |
87 | * |
88 | * Update the given list of PM QoS constraint requests, @c, by carrying an |
89 | * @action involving the @node list entry and @value on it. |
90 | * |
91 | * The recognized values of @action are PM_QOS_ADD_REQ (store @value in @node |
92 | * and add it to the list), PM_QOS_UPDATE_REQ (remove @node from the list, store |
93 | * @value in it and add it to the list again), and PM_QOS_REMOVE_REQ (remove |
94 | * @node from the list, ignore @value). |
95 | * |
96 | * Return: 1 if the aggregate constraint value has changed, 0 otherwise. |
97 | */ |
98 | int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node, |
99 | enum pm_qos_req_action action, int value) |
100 | { |
101 | int prev_value, curr_value, new_value; |
102 | unsigned long flags; |
103 | |
104 | spin_lock_irqsave(&pm_qos_lock, flags); |
105 | |
106 | prev_value = pm_qos_get_value(c); |
107 | if (value == PM_QOS_DEFAULT_VALUE) |
108 | new_value = c->default_value; |
109 | else |
110 | new_value = value; |
111 | |
112 | switch (action) { |
113 | case PM_QOS_REMOVE_REQ: |
114 | plist_del(node, head: &c->list); |
115 | break; |
116 | case PM_QOS_UPDATE_REQ: |
117 | /* |
118 | * To change the list, atomically remove, reinit with new value |
119 | * and add, then see if the aggregate has changed. |
120 | */ |
121 | plist_del(node, head: &c->list); |
122 | fallthrough; |
123 | case PM_QOS_ADD_REQ: |
124 | plist_node_init(node, prio: new_value); |
125 | plist_add(node, head: &c->list); |
126 | break; |
127 | default: |
128 | /* no action */ |
129 | ; |
130 | } |
131 | |
132 | curr_value = pm_qos_get_value(c); |
133 | pm_qos_set_value(c, value: curr_value); |
134 | |
135 | spin_unlock_irqrestore(lock: &pm_qos_lock, flags); |
136 | |
137 | trace_pm_qos_update_target(action, prev_value, curr_value); |
138 | |
139 | if (prev_value == curr_value) |
140 | return 0; |
141 | |
142 | if (c->notifiers) |
143 | blocking_notifier_call_chain(nh: c->notifiers, val: curr_value, NULL); |
144 | |
145 | return 1; |
146 | } |
147 | |
148 | /** |
149 | * pm_qos_flags_remove_req - Remove device PM QoS flags request. |
150 | * @pqf: Device PM QoS flags set to remove the request from. |
151 | * @req: Request to remove from the set. |
152 | */ |
153 | static void pm_qos_flags_remove_req(struct pm_qos_flags *pqf, |
154 | struct pm_qos_flags_request *req) |
155 | { |
156 | s32 val = 0; |
157 | |
158 | list_del(entry: &req->node); |
159 | list_for_each_entry(req, &pqf->list, node) |
160 | val |= req->flags; |
161 | |
162 | pqf->effective_flags = val; |
163 | } |
164 | |
165 | /** |
166 | * pm_qos_update_flags - Update a set of PM QoS flags. |
167 | * @pqf: Set of PM QoS flags to update. |
168 | * @req: Request to add to the set, to modify, or to remove from the set. |
169 | * @action: Action to take on the set. |
170 | * @val: Value of the request to add or modify. |
171 | * |
172 | * Return: 1 if the aggregate constraint value has changed, 0 otherwise. |
173 | */ |
174 | bool pm_qos_update_flags(struct pm_qos_flags *pqf, |
175 | struct pm_qos_flags_request *req, |
176 | enum pm_qos_req_action action, s32 val) |
177 | { |
178 | unsigned long irqflags; |
179 | s32 prev_value, curr_value; |
180 | |
181 | spin_lock_irqsave(&pm_qos_lock, irqflags); |
182 | |
183 | prev_value = list_empty(head: &pqf->list) ? 0 : pqf->effective_flags; |
184 | |
185 | switch (action) { |
186 | case PM_QOS_REMOVE_REQ: |
187 | pm_qos_flags_remove_req(pqf, req); |
188 | break; |
189 | case PM_QOS_UPDATE_REQ: |
190 | pm_qos_flags_remove_req(pqf, req); |
191 | fallthrough; |
192 | case PM_QOS_ADD_REQ: |
193 | req->flags = val; |
194 | INIT_LIST_HEAD(list: &req->node); |
195 | list_add_tail(new: &req->node, head: &pqf->list); |
196 | pqf->effective_flags |= val; |
197 | break; |
198 | default: |
199 | /* no action */ |
200 | ; |
201 | } |
202 | |
203 | curr_value = list_empty(head: &pqf->list) ? 0 : pqf->effective_flags; |
204 | |
205 | spin_unlock_irqrestore(lock: &pm_qos_lock, flags: irqflags); |
206 | |
207 | trace_pm_qos_update_flags(action, prev_value, curr_value); |
208 | |
209 | return prev_value != curr_value; |
210 | } |
211 | |
212 | #ifdef CONFIG_CPU_IDLE |
213 | /* Definitions related to the CPU latency QoS. */ |
214 | |
215 | static struct pm_qos_constraints cpu_latency_constraints = { |
216 | .list = PLIST_HEAD_INIT(cpu_latency_constraints.list), |
217 | .target_value = PM_QOS_CPU_LATENCY_DEFAULT_VALUE, |
218 | .default_value = PM_QOS_CPU_LATENCY_DEFAULT_VALUE, |
219 | .no_constraint_value = PM_QOS_CPU_LATENCY_DEFAULT_VALUE, |
220 | .type = PM_QOS_MIN, |
221 | }; |
222 | |
223 | static inline bool cpu_latency_qos_value_invalid(s32 value) |
224 | { |
225 | return value < 0 && value != PM_QOS_DEFAULT_VALUE; |
226 | } |
227 | |
228 | /** |
229 | * cpu_latency_qos_limit - Return current system-wide CPU latency QoS limit. |
230 | */ |
231 | s32 cpu_latency_qos_limit(void) |
232 | { |
233 | return pm_qos_read_value(c: &cpu_latency_constraints); |
234 | } |
235 | |
236 | /** |
237 | * cpu_latency_qos_request_active - Check the given PM QoS request. |
238 | * @req: PM QoS request to check. |
239 | * |
240 | * Return: 'true' if @req has been added to the CPU latency QoS list, 'false' |
241 | * otherwise. |
242 | */ |
243 | bool cpu_latency_qos_request_active(struct pm_qos_request *req) |
244 | { |
245 | return req->qos == &cpu_latency_constraints; |
246 | } |
247 | EXPORT_SYMBOL_GPL(cpu_latency_qos_request_active); |
248 | |
249 | static void cpu_latency_qos_apply(struct pm_qos_request *req, |
250 | enum pm_qos_req_action action, s32 value) |
251 | { |
252 | int ret = pm_qos_update_target(c: req->qos, node: &req->node, action, value); |
253 | if (ret > 0) |
254 | wake_up_all_idle_cpus(); |
255 | } |
256 | |
257 | /** |
258 | * cpu_latency_qos_add_request - Add new CPU latency QoS request. |
259 | * @req: Pointer to a preallocated handle. |
260 | * @value: Requested constraint value. |
261 | * |
262 | * Use @value to initialize the request handle pointed to by @req, insert it as |
263 | * a new entry to the CPU latency QoS list and recompute the effective QoS |
264 | * constraint for that list. |
265 | * |
266 | * Callers need to save the handle for later use in updates and removal of the |
267 | * QoS request represented by it. |
268 | */ |
269 | void cpu_latency_qos_add_request(struct pm_qos_request *req, s32 value) |
270 | { |
271 | if (!req || cpu_latency_qos_value_invalid(value)) |
272 | return; |
273 | |
274 | if (cpu_latency_qos_request_active(req)) { |
275 | WARN(1, KERN_ERR "%s called for already added request\n" , __func__); |
276 | return; |
277 | } |
278 | |
279 | trace_pm_qos_add_request(value); |
280 | |
281 | req->qos = &cpu_latency_constraints; |
282 | cpu_latency_qos_apply(req, action: PM_QOS_ADD_REQ, value); |
283 | } |
284 | EXPORT_SYMBOL_GPL(cpu_latency_qos_add_request); |
285 | |
286 | /** |
287 | * cpu_latency_qos_update_request - Modify existing CPU latency QoS request. |
288 | * @req : QoS request to update. |
289 | * @new_value: New requested constraint value. |
290 | * |
291 | * Use @new_value to update the QoS request represented by @req in the CPU |
292 | * latency QoS list along with updating the effective constraint value for that |
293 | * list. |
294 | */ |
295 | void cpu_latency_qos_update_request(struct pm_qos_request *req, s32 new_value) |
296 | { |
297 | if (!req || cpu_latency_qos_value_invalid(value: new_value)) |
298 | return; |
299 | |
300 | if (!cpu_latency_qos_request_active(req)) { |
301 | WARN(1, KERN_ERR "%s called for unknown object\n" , __func__); |
302 | return; |
303 | } |
304 | |
305 | trace_pm_qos_update_request(value: new_value); |
306 | |
307 | if (new_value == req->node.prio) |
308 | return; |
309 | |
310 | cpu_latency_qos_apply(req, action: PM_QOS_UPDATE_REQ, value: new_value); |
311 | } |
312 | EXPORT_SYMBOL_GPL(cpu_latency_qos_update_request); |
313 | |
314 | /** |
315 | * cpu_latency_qos_remove_request - Remove existing CPU latency QoS request. |
316 | * @req: QoS request to remove. |
317 | * |
318 | * Remove the CPU latency QoS request represented by @req from the CPU latency |
319 | * QoS list along with updating the effective constraint value for that list. |
320 | */ |
321 | void cpu_latency_qos_remove_request(struct pm_qos_request *req) |
322 | { |
323 | if (!req) |
324 | return; |
325 | |
326 | if (!cpu_latency_qos_request_active(req)) { |
327 | WARN(1, KERN_ERR "%s called for unknown object\n" , __func__); |
328 | return; |
329 | } |
330 | |
331 | trace_pm_qos_remove_request(PM_QOS_DEFAULT_VALUE); |
332 | |
333 | cpu_latency_qos_apply(req, action: PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE); |
334 | memset(req, 0, sizeof(*req)); |
335 | } |
336 | EXPORT_SYMBOL_GPL(cpu_latency_qos_remove_request); |
337 | |
338 | /* User space interface to the CPU latency QoS via misc device. */ |
339 | |
340 | static int cpu_latency_qos_open(struct inode *inode, struct file *filp) |
341 | { |
342 | struct pm_qos_request *req; |
343 | |
344 | req = kzalloc(size: sizeof(*req), GFP_KERNEL); |
345 | if (!req) |
346 | return -ENOMEM; |
347 | |
348 | cpu_latency_qos_add_request(req, PM_QOS_DEFAULT_VALUE); |
349 | filp->private_data = req; |
350 | |
351 | return 0; |
352 | } |
353 | |
354 | static int cpu_latency_qos_release(struct inode *inode, struct file *filp) |
355 | { |
356 | struct pm_qos_request *req = filp->private_data; |
357 | |
358 | filp->private_data = NULL; |
359 | |
360 | cpu_latency_qos_remove_request(req); |
361 | kfree(objp: req); |
362 | |
363 | return 0; |
364 | } |
365 | |
366 | static ssize_t cpu_latency_qos_read(struct file *filp, char __user *buf, |
367 | size_t count, loff_t *f_pos) |
368 | { |
369 | struct pm_qos_request *req = filp->private_data; |
370 | unsigned long flags; |
371 | s32 value; |
372 | |
373 | if (!req || !cpu_latency_qos_request_active(req)) |
374 | return -EINVAL; |
375 | |
376 | spin_lock_irqsave(&pm_qos_lock, flags); |
377 | value = pm_qos_get_value(c: &cpu_latency_constraints); |
378 | spin_unlock_irqrestore(lock: &pm_qos_lock, flags); |
379 | |
380 | return simple_read_from_buffer(to: buf, count, ppos: f_pos, from: &value, available: sizeof(s32)); |
381 | } |
382 | |
383 | static ssize_t cpu_latency_qos_write(struct file *filp, const char __user *buf, |
384 | size_t count, loff_t *f_pos) |
385 | { |
386 | s32 value; |
387 | |
388 | if (count == sizeof(s32)) { |
389 | if (copy_from_user(to: &value, from: buf, n: sizeof(s32))) |
390 | return -EFAULT; |
391 | } else { |
392 | int ret; |
393 | |
394 | ret = kstrtos32_from_user(s: buf, count, base: 16, res: &value); |
395 | if (ret) |
396 | return ret; |
397 | } |
398 | |
399 | cpu_latency_qos_update_request(filp->private_data, value); |
400 | |
401 | return count; |
402 | } |
403 | |
404 | static const struct file_operations cpu_latency_qos_fops = { |
405 | .write = cpu_latency_qos_write, |
406 | .read = cpu_latency_qos_read, |
407 | .open = cpu_latency_qos_open, |
408 | .release = cpu_latency_qos_release, |
409 | .llseek = noop_llseek, |
410 | }; |
411 | |
412 | static struct miscdevice cpu_latency_qos_miscdev = { |
413 | .minor = MISC_DYNAMIC_MINOR, |
414 | .name = "cpu_dma_latency" , |
415 | .fops = &cpu_latency_qos_fops, |
416 | }; |
417 | |
418 | static int __init cpu_latency_qos_init(void) |
419 | { |
420 | int ret; |
421 | |
422 | ret = misc_register(misc: &cpu_latency_qos_miscdev); |
423 | if (ret < 0) |
424 | pr_err("%s: %s setup failed\n" , __func__, |
425 | cpu_latency_qos_miscdev.name); |
426 | |
427 | return ret; |
428 | } |
429 | late_initcall(cpu_latency_qos_init); |
430 | #endif /* CONFIG_CPU_IDLE */ |
431 | |
432 | /* Definitions related to the frequency QoS below. */ |
433 | |
434 | static inline bool freq_qos_value_invalid(s32 value) |
435 | { |
436 | return value < 0 && value != PM_QOS_DEFAULT_VALUE; |
437 | } |
438 | |
439 | /** |
440 | * freq_constraints_init - Initialize frequency QoS constraints. |
441 | * @qos: Frequency QoS constraints to initialize. |
442 | */ |
443 | void freq_constraints_init(struct freq_constraints *qos) |
444 | { |
445 | struct pm_qos_constraints *c; |
446 | |
447 | c = &qos->min_freq; |
448 | plist_head_init(head: &c->list); |
449 | c->target_value = FREQ_QOS_MIN_DEFAULT_VALUE; |
450 | c->default_value = FREQ_QOS_MIN_DEFAULT_VALUE; |
451 | c->no_constraint_value = FREQ_QOS_MIN_DEFAULT_VALUE; |
452 | c->type = PM_QOS_MAX; |
453 | c->notifiers = &qos->min_freq_notifiers; |
454 | BLOCKING_INIT_NOTIFIER_HEAD(c->notifiers); |
455 | |
456 | c = &qos->max_freq; |
457 | plist_head_init(head: &c->list); |
458 | c->target_value = FREQ_QOS_MAX_DEFAULT_VALUE; |
459 | c->default_value = FREQ_QOS_MAX_DEFAULT_VALUE; |
460 | c->no_constraint_value = FREQ_QOS_MAX_DEFAULT_VALUE; |
461 | c->type = PM_QOS_MIN; |
462 | c->notifiers = &qos->max_freq_notifiers; |
463 | BLOCKING_INIT_NOTIFIER_HEAD(c->notifiers); |
464 | } |
465 | |
466 | /** |
467 | * freq_qos_read_value - Get frequency QoS constraint for a given list. |
468 | * @qos: Constraints to evaluate. |
469 | * @type: QoS request type. |
470 | */ |
471 | s32 freq_qos_read_value(struct freq_constraints *qos, |
472 | enum freq_qos_req_type type) |
473 | { |
474 | s32 ret; |
475 | |
476 | switch (type) { |
477 | case FREQ_QOS_MIN: |
478 | ret = IS_ERR_OR_NULL(ptr: qos) ? |
479 | FREQ_QOS_MIN_DEFAULT_VALUE : |
480 | pm_qos_read_value(c: &qos->min_freq); |
481 | break; |
482 | case FREQ_QOS_MAX: |
483 | ret = IS_ERR_OR_NULL(ptr: qos) ? |
484 | FREQ_QOS_MAX_DEFAULT_VALUE : |
485 | pm_qos_read_value(c: &qos->max_freq); |
486 | break; |
487 | default: |
488 | WARN_ON(1); |
489 | ret = 0; |
490 | } |
491 | |
492 | return ret; |
493 | } |
494 | |
495 | /** |
496 | * freq_qos_apply - Add/modify/remove frequency QoS request. |
497 | * @req: Constraint request to apply. |
498 | * @action: Action to perform (add/update/remove). |
499 | * @value: Value to assign to the QoS request. |
500 | * |
501 | * This is only meant to be called from inside pm_qos, not drivers. |
502 | */ |
503 | int freq_qos_apply(struct freq_qos_request *req, |
504 | enum pm_qos_req_action action, s32 value) |
505 | { |
506 | int ret; |
507 | |
508 | switch(req->type) { |
509 | case FREQ_QOS_MIN: |
510 | ret = pm_qos_update_target(c: &req->qos->min_freq, node: &req->pnode, |
511 | action, value); |
512 | break; |
513 | case FREQ_QOS_MAX: |
514 | ret = pm_qos_update_target(c: &req->qos->max_freq, node: &req->pnode, |
515 | action, value); |
516 | break; |
517 | default: |
518 | ret = -EINVAL; |
519 | } |
520 | |
521 | return ret; |
522 | } |
523 | |
524 | /** |
525 | * freq_qos_add_request - Insert new frequency QoS request into a given list. |
526 | * @qos: Constraints to update. |
527 | * @req: Preallocated request object. |
528 | * @type: Request type. |
529 | * @value: Request value. |
530 | * |
531 | * Insert a new entry into the @qos list of requests, recompute the effective |
532 | * QoS constraint value for that list and initialize the @req object. The |
533 | * caller needs to save that object for later use in updates and removal. |
534 | * |
535 | * Return 1 if the effective constraint value has changed, 0 if the effective |
536 | * constraint value has not changed, or a negative error code on failures. |
537 | */ |
538 | int freq_qos_add_request(struct freq_constraints *qos, |
539 | struct freq_qos_request *req, |
540 | enum freq_qos_req_type type, s32 value) |
541 | { |
542 | int ret; |
543 | |
544 | if (IS_ERR_OR_NULL(ptr: qos) || !req || freq_qos_value_invalid(value)) |
545 | return -EINVAL; |
546 | |
547 | if (WARN(freq_qos_request_active(req), |
548 | "%s() called for active request\n" , __func__)) |
549 | return -EINVAL; |
550 | |
551 | req->qos = qos; |
552 | req->type = type; |
553 | ret = freq_qos_apply(req, action: PM_QOS_ADD_REQ, value); |
554 | if (ret < 0) { |
555 | req->qos = NULL; |
556 | req->type = 0; |
557 | } |
558 | |
559 | return ret; |
560 | } |
561 | EXPORT_SYMBOL_GPL(freq_qos_add_request); |
562 | |
563 | /** |
564 | * freq_qos_update_request - Modify existing frequency QoS request. |
565 | * @req: Request to modify. |
566 | * @new_value: New request value. |
567 | * |
568 | * Update an existing frequency QoS request along with the effective constraint |
569 | * value for the list of requests it belongs to. |
570 | * |
571 | * Return 1 if the effective constraint value has changed, 0 if the effective |
572 | * constraint value has not changed, or a negative error code on failures. |
573 | */ |
574 | int freq_qos_update_request(struct freq_qos_request *req, s32 new_value) |
575 | { |
576 | if (!req || freq_qos_value_invalid(value: new_value)) |
577 | return -EINVAL; |
578 | |
579 | if (WARN(!freq_qos_request_active(req), |
580 | "%s() called for unknown object\n" , __func__)) |
581 | return -EINVAL; |
582 | |
583 | if (req->pnode.prio == new_value) |
584 | return 0; |
585 | |
586 | return freq_qos_apply(req, action: PM_QOS_UPDATE_REQ, value: new_value); |
587 | } |
588 | EXPORT_SYMBOL_GPL(freq_qos_update_request); |
589 | |
590 | /** |
591 | * freq_qos_remove_request - Remove frequency QoS request from its list. |
592 | * @req: Request to remove. |
593 | * |
594 | * Remove the given frequency QoS request from the list of constraints it |
595 | * belongs to and recompute the effective constraint value for that list. |
596 | * |
597 | * Return 1 if the effective constraint value has changed, 0 if the effective |
598 | * constraint value has not changed, or a negative error code on failures. |
599 | */ |
600 | int freq_qos_remove_request(struct freq_qos_request *req) |
601 | { |
602 | int ret; |
603 | |
604 | if (!req) |
605 | return -EINVAL; |
606 | |
607 | if (WARN(!freq_qos_request_active(req), |
608 | "%s() called for unknown object\n" , __func__)) |
609 | return -EINVAL; |
610 | |
611 | ret = freq_qos_apply(req, action: PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE); |
612 | req->qos = NULL; |
613 | req->type = 0; |
614 | |
615 | return ret; |
616 | } |
617 | EXPORT_SYMBOL_GPL(freq_qos_remove_request); |
618 | |
619 | /** |
620 | * freq_qos_add_notifier - Add frequency QoS change notifier. |
621 | * @qos: List of requests to add the notifier to. |
622 | * @type: Request type. |
623 | * @notifier: Notifier block to add. |
624 | */ |
625 | int freq_qos_add_notifier(struct freq_constraints *qos, |
626 | enum freq_qos_req_type type, |
627 | struct notifier_block *notifier) |
628 | { |
629 | int ret; |
630 | |
631 | if (IS_ERR_OR_NULL(ptr: qos) || !notifier) |
632 | return -EINVAL; |
633 | |
634 | switch (type) { |
635 | case FREQ_QOS_MIN: |
636 | ret = blocking_notifier_chain_register(nh: qos->min_freq.notifiers, |
637 | nb: notifier); |
638 | break; |
639 | case FREQ_QOS_MAX: |
640 | ret = blocking_notifier_chain_register(nh: qos->max_freq.notifiers, |
641 | nb: notifier); |
642 | break; |
643 | default: |
644 | WARN_ON(1); |
645 | ret = -EINVAL; |
646 | } |
647 | |
648 | return ret; |
649 | } |
650 | EXPORT_SYMBOL_GPL(freq_qos_add_notifier); |
651 | |
652 | /** |
653 | * freq_qos_remove_notifier - Remove frequency QoS change notifier. |
654 | * @qos: List of requests to remove the notifier from. |
655 | * @type: Request type. |
656 | * @notifier: Notifier block to remove. |
657 | */ |
658 | int freq_qos_remove_notifier(struct freq_constraints *qos, |
659 | enum freq_qos_req_type type, |
660 | struct notifier_block *notifier) |
661 | { |
662 | int ret; |
663 | |
664 | if (IS_ERR_OR_NULL(ptr: qos) || !notifier) |
665 | return -EINVAL; |
666 | |
667 | switch (type) { |
668 | case FREQ_QOS_MIN: |
669 | ret = blocking_notifier_chain_unregister(nh: qos->min_freq.notifiers, |
670 | nb: notifier); |
671 | break; |
672 | case FREQ_QOS_MAX: |
673 | ret = blocking_notifier_chain_unregister(nh: qos->max_freq.notifiers, |
674 | nb: notifier); |
675 | break; |
676 | default: |
677 | WARN_ON(1); |
678 | ret = -EINVAL; |
679 | } |
680 | |
681 | return ret; |
682 | } |
683 | EXPORT_SYMBOL_GPL(freq_qos_remove_notifier); |
684 | |