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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 */
47static 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 */
53s32 pm_qos_read_value(struct pm_qos_constraints *c)
54{
55 return READ_ONCE(c->target_value);
56}
57
58static int pm_qos_get_value(struct pm_qos_constraints *c)
59{
60 if (plist_head_empty(&c->list))
61 return c->no_constraint_value;
62
63 switch (c->type) {
64 case PM_QOS_MIN:
65 return plist_first(&c->list)->prio;
66
67 case PM_QOS_MAX:
68 return plist_last(&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
76static 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 */
98int 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, &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, &c->list);
122 fallthrough;
123 case PM_QOS_ADD_REQ:
124 plist_node_init(node, new_value);
125 plist_add(node, &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, curr_value);
134
135 spin_unlock_irqrestore(&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(c->notifiers, 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 */
153static 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(&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 */
174bool 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(&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(&req->node);
195 list_add_tail(&req->node, &pqf->list);
196 pqf->effective_flags |= val;
197 break;
198 default:
199 /* no action */
200 ;
201 }
202
203 curr_value = list_empty(&pqf->list) ? 0 : pqf->effective_flags;
204
205 spin_unlock_irqrestore(&pm_qos_lock, 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
215static 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/**
224 * cpu_latency_qos_limit - Return current system-wide CPU latency QoS limit.
225 */
226s32 cpu_latency_qos_limit(void)
227{
228 return pm_qos_read_value(&cpu_latency_constraints);
229}
230
231/**
232 * cpu_latency_qos_request_active - Check the given PM QoS request.
233 * @req: PM QoS request to check.
234 *
235 * Return: 'true' if @req has been added to the CPU latency QoS list, 'false'
236 * otherwise.
237 */
238bool cpu_latency_qos_request_active(struct pm_qos_request *req)
239{
240 return req->qos == &cpu_latency_constraints;
241}
242EXPORT_SYMBOL_GPL(cpu_latency_qos_request_active);
243
244static void cpu_latency_qos_apply(struct pm_qos_request *req,
245 enum pm_qos_req_action action, s32 value)
246{
247 int ret = pm_qos_update_target(req->qos, &req->node, action, value);
248 if (ret > 0)
249 wake_up_all_idle_cpus();
250}
251
252/**
253 * cpu_latency_qos_add_request - Add new CPU latency QoS request.
254 * @req: Pointer to a preallocated handle.
255 * @value: Requested constraint value.
256 *
257 * Use @value to initialize the request handle pointed to by @req, insert it as
258 * a new entry to the CPU latency QoS list and recompute the effective QoS
259 * constraint for that list.
260 *
261 * Callers need to save the handle for later use in updates and removal of the
262 * QoS request represented by it.
263 */
264void cpu_latency_qos_add_request(struct pm_qos_request *req, s32 value)
265{
266 if (!req)
267 return;
268
269 if (cpu_latency_qos_request_active(req)) {
270 WARN(1, KERN_ERR "%s called for already added request\n", __func__);
271 return;
272 }
273
274 trace_pm_qos_add_request(value);
275
276 req->qos = &cpu_latency_constraints;
277 cpu_latency_qos_apply(req, PM_QOS_ADD_REQ, value);
278}
279EXPORT_SYMBOL_GPL(cpu_latency_qos_add_request);
280
281/**
282 * cpu_latency_qos_update_request - Modify existing CPU latency QoS request.
283 * @req : QoS request to update.
284 * @new_value: New requested constraint value.
285 *
286 * Use @new_value to update the QoS request represented by @req in the CPU
287 * latency QoS list along with updating the effective constraint value for that
288 * list.
289 */
290void cpu_latency_qos_update_request(struct pm_qos_request *req, s32 new_value)
291{
292 if (!req)
293 return;
294
295 if (!cpu_latency_qos_request_active(req)) {
296 WARN(1, KERN_ERR "%s called for unknown object\n", __func__);
297 return;
298 }
299
300 trace_pm_qos_update_request(new_value);
301
302 if (new_value == req->node.prio)
303 return;
304
305 cpu_latency_qos_apply(req, PM_QOS_UPDATE_REQ, new_value);
306}
307EXPORT_SYMBOL_GPL(cpu_latency_qos_update_request);
308
309/**
310 * cpu_latency_qos_remove_request - Remove existing CPU latency QoS request.
311 * @req: QoS request to remove.
312 *
313 * Remove the CPU latency QoS request represented by @req from the CPU latency
314 * QoS list along with updating the effective constraint value for that list.
315 */
316void cpu_latency_qos_remove_request(struct pm_qos_request *req)
317{
318 if (!req)
319 return;
320
321 if (!cpu_latency_qos_request_active(req)) {
322 WARN(1, KERN_ERR "%s called for unknown object\n", __func__);
323 return;
324 }
325
326 trace_pm_qos_remove_request(PM_QOS_DEFAULT_VALUE);
327
328 cpu_latency_qos_apply(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
329 memset(req, 0, sizeof(*req));
330}
331EXPORT_SYMBOL_GPL(cpu_latency_qos_remove_request);
332
333/* User space interface to the CPU latency QoS via misc device. */
334
335static int cpu_latency_qos_open(struct inode *inode, struct file *filp)
336{
337 struct pm_qos_request *req;
338
339 req = kzalloc(sizeof(*req), GFP_KERNEL);
340 if (!req)
341 return -ENOMEM;
342
343 cpu_latency_qos_add_request(req, PM_QOS_DEFAULT_VALUE);
344 filp->private_data = req;
345
346 return 0;
347}
348
349static int cpu_latency_qos_release(struct inode *inode, struct file *filp)
350{
351 struct pm_qos_request *req = filp->private_data;
352
353 filp->private_data = NULL;
354
355 cpu_latency_qos_remove_request(req);
356 kfree(req);
357
358 return 0;
359}
360
361static ssize_t cpu_latency_qos_read(struct file *filp, char __user *buf,
362 size_t count, loff_t *f_pos)
363{
364 struct pm_qos_request *req = filp->private_data;
365 unsigned long flags;
366 s32 value;
367
368 if (!req || !cpu_latency_qos_request_active(req))
369 return -EINVAL;
370
371 spin_lock_irqsave(&pm_qos_lock, flags);
372 value = pm_qos_get_value(&cpu_latency_constraints);
373 spin_unlock_irqrestore(&pm_qos_lock, flags);
374
375 return simple_read_from_buffer(buf, count, f_pos, &value, sizeof(s32));
376}
377
378static ssize_t cpu_latency_qos_write(struct file *filp, const char __user *buf,
379 size_t count, loff_t *f_pos)
380{
381 s32 value;
382
383 if (count == sizeof(s32)) {
384 if (copy_from_user(&value, buf, sizeof(s32)))
385 return -EFAULT;
386 } else {
387 int ret;
388
389 ret = kstrtos32_from_user(buf, count, 16, &value);
390 if (ret)
391 return ret;
392 }
393
394 cpu_latency_qos_update_request(filp->private_data, value);
395
396 return count;
397}
398
399static const struct file_operations cpu_latency_qos_fops = {
400 .write = cpu_latency_qos_write,
401 .read = cpu_latency_qos_read,
402 .open = cpu_latency_qos_open,
403 .release = cpu_latency_qos_release,
404 .llseek = noop_llseek,
405};
406
407static struct miscdevice cpu_latency_qos_miscdev = {
408 .minor = MISC_DYNAMIC_MINOR,
409 .name = "cpu_dma_latency",
410 .fops = &cpu_latency_qos_fops,
411};
412
413static int __init cpu_latency_qos_init(void)
414{
415 int ret;
416
417 ret = misc_register(&cpu_latency_qos_miscdev);
418 if (ret < 0)
419 pr_err("%s: %s setup failed\n", __func__,
420 cpu_latency_qos_miscdev.name);
421
422 return ret;
423}
424late_initcall(cpu_latency_qos_init);
425#endif /* CONFIG_CPU_IDLE */
426
427/* Definitions related to the frequency QoS below. */
428
429/**
430 * freq_constraints_init - Initialize frequency QoS constraints.
431 * @qos: Frequency QoS constraints to initialize.
432 */
433void freq_constraints_init(struct freq_constraints *qos)
434{
435 struct pm_qos_constraints *c;
436
437 c = &qos->min_freq;
438 plist_head_init(&c->list);
439 c->target_value = FREQ_QOS_MIN_DEFAULT_VALUE;
440 c->default_value = FREQ_QOS_MIN_DEFAULT_VALUE;
441 c->no_constraint_value = FREQ_QOS_MIN_DEFAULT_VALUE;
442 c->type = PM_QOS_MAX;
443 c->notifiers = &qos->min_freq_notifiers;
444 BLOCKING_INIT_NOTIFIER_HEAD(c->notifiers);
445
446 c = &qos->max_freq;
447 plist_head_init(&c->list);
448 c->target_value = FREQ_QOS_MAX_DEFAULT_VALUE;
449 c->default_value = FREQ_QOS_MAX_DEFAULT_VALUE;
450 c->no_constraint_value = FREQ_QOS_MAX_DEFAULT_VALUE;
451 c->type = PM_QOS_MIN;
452 c->notifiers = &qos->max_freq_notifiers;
453 BLOCKING_INIT_NOTIFIER_HEAD(c->notifiers);
454}
455
456/**
457 * freq_qos_read_value - Get frequency QoS constraint for a given list.
458 * @qos: Constraints to evaluate.
459 * @type: QoS request type.
460 */
461s32 freq_qos_read_value(struct freq_constraints *qos,
462 enum freq_qos_req_type type)
463{
464 s32 ret;
465
466 switch (type) {
467 case FREQ_QOS_MIN:
468 ret = IS_ERR_OR_NULL(qos) ?
469 FREQ_QOS_MIN_DEFAULT_VALUE :
470 pm_qos_read_value(&qos->min_freq);
471 break;
472 case FREQ_QOS_MAX:
473 ret = IS_ERR_OR_NULL(qos) ?
474 FREQ_QOS_MAX_DEFAULT_VALUE :
475 pm_qos_read_value(&qos->max_freq);
476 break;
477 default:
478 WARN_ON(1);
479 ret = 0;
480 }
481
482 return ret;
483}
484
485/**
486 * freq_qos_apply - Add/modify/remove frequency QoS request.
487 * @req: Constraint request to apply.
488 * @action: Action to perform (add/update/remove).
489 * @value: Value to assign to the QoS request.
490 *
491 * This is only meant to be called from inside pm_qos, not drivers.
492 */
493int freq_qos_apply(struct freq_qos_request *req,
494 enum pm_qos_req_action action, s32 value)
495{
496 int ret;
497
498 switch(req->type) {
499 case FREQ_QOS_MIN:
500 ret = pm_qos_update_target(&req->qos->min_freq, &req->pnode,
501 action, value);
502 break;
503 case FREQ_QOS_MAX:
504 ret = pm_qos_update_target(&req->qos->max_freq, &req->pnode,
505 action, value);
506 break;
507 default:
508 ret = -EINVAL;
509 }
510
511 return ret;
512}
513
514/**
515 * freq_qos_add_request - Insert new frequency QoS request into a given list.
516 * @qos: Constraints to update.
517 * @req: Preallocated request object.
518 * @type: Request type.
519 * @value: Request value.
520 *
521 * Insert a new entry into the @qos list of requests, recompute the effective
522 * QoS constraint value for that list and initialize the @req object. The
523 * caller needs to save that object for later use in updates and removal.
524 *
525 * Return 1 if the effective constraint value has changed, 0 if the effective
526 * constraint value has not changed, or a negative error code on failures.
527 */
528int freq_qos_add_request(struct freq_constraints *qos,
529 struct freq_qos_request *req,
530 enum freq_qos_req_type type, s32 value)
531{
532 int ret;
533
534 if (IS_ERR_OR_NULL(qos) || !req || value < 0)
535 return -EINVAL;
536
537 if (WARN(freq_qos_request_active(req),
538 "%s() called for active request\n", __func__))
539 return -EINVAL;
540
541 req->qos = qos;
542 req->type = type;
543 ret = freq_qos_apply(req, PM_QOS_ADD_REQ, value);
544 if (ret < 0) {
545 req->qos = NULL;
546 req->type = 0;
547 }
548
549 return ret;
550}
551EXPORT_SYMBOL_GPL(freq_qos_add_request);
552
553/**
554 * freq_qos_update_request - Modify existing frequency QoS request.
555 * @req: Request to modify.
556 * @new_value: New request value.
557 *
558 * Update an existing frequency QoS request along with the effective constraint
559 * value for the list of requests it belongs to.
560 *
561 * Return 1 if the effective constraint value has changed, 0 if the effective
562 * constraint value has not changed, or a negative error code on failures.
563 */
564int freq_qos_update_request(struct freq_qos_request *req, s32 new_value)
565{
566 if (!req || new_value < 0)
567 return -EINVAL;
568
569 if (WARN(!freq_qos_request_active(req),
570 "%s() called for unknown object\n", __func__))
571 return -EINVAL;
572
573 if (req->pnode.prio == new_value)
574 return 0;
575
576 return freq_qos_apply(req, PM_QOS_UPDATE_REQ, new_value);
577}
578EXPORT_SYMBOL_GPL(freq_qos_update_request);
579
580/**
581 * freq_qos_remove_request - Remove frequency QoS request from its list.
582 * @req: Request to remove.
583 *
584 * Remove the given frequency QoS request from the list of constraints it
585 * belongs to and recompute the effective constraint value for that list.
586 *
587 * Return 1 if the effective constraint value has changed, 0 if the effective
588 * constraint value has not changed, or a negative error code on failures.
589 */
590int freq_qos_remove_request(struct freq_qos_request *req)
591{
592 int ret;
593
594 if (!req)
595 return -EINVAL;
596
597 if (WARN(!freq_qos_request_active(req),
598 "%s() called for unknown object\n", __func__))
599 return -EINVAL;
600
601 ret = freq_qos_apply(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
602 req->qos = NULL;
603 req->type = 0;
604
605 return ret;
606}
607EXPORT_SYMBOL_GPL(freq_qos_remove_request);
608
609/**
610 * freq_qos_add_notifier - Add frequency QoS change notifier.
611 * @qos: List of requests to add the notifier to.
612 * @type: Request type.
613 * @notifier: Notifier block to add.
614 */
615int freq_qos_add_notifier(struct freq_constraints *qos,
616 enum freq_qos_req_type type,
617 struct notifier_block *notifier)
618{
619 int ret;
620
621 if (IS_ERR_OR_NULL(qos) || !notifier)
622 return -EINVAL;
623
624 switch (type) {
625 case FREQ_QOS_MIN:
626 ret = blocking_notifier_chain_register(qos->min_freq.notifiers,
627 notifier);
628 break;
629 case FREQ_QOS_MAX:
630 ret = blocking_notifier_chain_register(qos->max_freq.notifiers,
631 notifier);
632 break;
633 default:
634 WARN_ON(1);
635 ret = -EINVAL;
636 }
637
638 return ret;
639}
640EXPORT_SYMBOL_GPL(freq_qos_add_notifier);
641
642/**
643 * freq_qos_remove_notifier - Remove frequency QoS change notifier.
644 * @qos: List of requests to remove the notifier from.
645 * @type: Request type.
646 * @notifier: Notifier block to remove.
647 */
648int freq_qos_remove_notifier(struct freq_constraints *qos,
649 enum freq_qos_req_type type,
650 struct notifier_block *notifier)
651{
652 int ret;
653
654 if (IS_ERR_OR_NULL(qos) || !notifier)
655 return -EINVAL;
656
657 switch (type) {
658 case FREQ_QOS_MIN:
659 ret = blocking_notifier_chain_unregister(qos->min_freq.notifiers,
660 notifier);
661 break;
662 case FREQ_QOS_MAX:
663 ret = blocking_notifier_chain_unregister(qos->max_freq.notifiers,
664 notifier);
665 break;
666 default:
667 WARN_ON(1);
668 ret = -EINVAL;
669 }
670
671 return ret;
672}
673EXPORT_SYMBOL_GPL(freq_qos_remove_notifier);
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 */
47static 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 */
53s32 pm_qos_read_value(struct pm_qos_constraints *c)
54{
55 return READ_ONCE(c->target_value);
56}
57
58static int pm_qos_get_value(struct pm_qos_constraints *c)
59{
60 if (plist_head_empty(&c->list))
61 return c->no_constraint_value;
62
63 switch (c->type) {
64 case PM_QOS_MIN:
65 return plist_first(&c->list)->prio;
66
67 case PM_QOS_MAX:
68 return plist_last(&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
76static 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 */
98int 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, &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, &c->list);
122 fallthrough;
123 case PM_QOS_ADD_REQ:
124 plist_node_init(node, new_value);
125 plist_add(node, &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, curr_value);
134
135 spin_unlock_irqrestore(&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(c->notifiers, 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 */
153static 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(&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 */
174bool 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(&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(&req->node);
195 list_add_tail(&req->node, &pqf->list);
196 pqf->effective_flags |= val;
197 break;
198 default:
199 /* no action */
200 ;
201 }
202
203 curr_value = list_empty(&pqf->list) ? 0 : pqf->effective_flags;
204
205 spin_unlock_irqrestore(&pm_qos_lock, 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
215static 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
223static 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 */
231s32 cpu_latency_qos_limit(void)
232{
233 return pm_qos_read_value(&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 */
243bool cpu_latency_qos_request_active(struct pm_qos_request *req)
244{
245 return req->qos == &cpu_latency_constraints;
246}
247EXPORT_SYMBOL_GPL(cpu_latency_qos_request_active);
248
249static 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(req->qos, &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 */
269void 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, PM_QOS_ADD_REQ, value);
283}
284EXPORT_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 */
295void cpu_latency_qos_update_request(struct pm_qos_request *req, s32 new_value)
296{
297 if (!req || cpu_latency_qos_value_invalid(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(new_value);
306
307 if (new_value == req->node.prio)
308 return;
309
310 cpu_latency_qos_apply(req, PM_QOS_UPDATE_REQ, new_value);
311}
312EXPORT_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 */
321void 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, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
334 memset(req, 0, sizeof(*req));
335}
336EXPORT_SYMBOL_GPL(cpu_latency_qos_remove_request);
337
338/* User space interface to the CPU latency QoS via misc device. */
339
340static int cpu_latency_qos_open(struct inode *inode, struct file *filp)
341{
342 struct pm_qos_request *req;
343
344 req = kzalloc(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
354static 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(req);
362
363 return 0;
364}
365
366static 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(&cpu_latency_constraints);
378 spin_unlock_irqrestore(&pm_qos_lock, flags);
379
380 return simple_read_from_buffer(buf, count, f_pos, &value, sizeof(s32));
381}
382
383static 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(&value, buf, sizeof(s32)))
390 return -EFAULT;
391 } else {
392 int ret;
393
394 ret = kstrtos32_from_user(buf, count, 16, &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
404static 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
412static struct miscdevice cpu_latency_qos_miscdev = {
413 .minor = MISC_DYNAMIC_MINOR,
414 .name = "cpu_dma_latency",
415 .fops = &cpu_latency_qos_fops,
416};
417
418static int __init cpu_latency_qos_init(void)
419{
420 int ret;
421
422 ret = misc_register(&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}
429late_initcall(cpu_latency_qos_init);
430#endif /* CONFIG_CPU_IDLE */
431
432/* Definitions related to the frequency QoS below. */
433
434static 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 */
443void freq_constraints_init(struct freq_constraints *qos)
444{
445 struct pm_qos_constraints *c;
446
447 c = &qos->min_freq;
448 plist_head_init(&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(&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 */
471s32 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(qos) ?
479 FREQ_QOS_MIN_DEFAULT_VALUE :
480 pm_qos_read_value(&qos->min_freq);
481 break;
482 case FREQ_QOS_MAX:
483 ret = IS_ERR_OR_NULL(qos) ?
484 FREQ_QOS_MAX_DEFAULT_VALUE :
485 pm_qos_read_value(&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 */
503int 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(&req->qos->min_freq, &req->pnode,
511 action, value);
512 break;
513 case FREQ_QOS_MAX:
514 ret = pm_qos_update_target(&req->qos->max_freq, &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 */
538int 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(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, PM_QOS_ADD_REQ, value);
554 if (ret < 0) {
555 req->qos = NULL;
556 req->type = 0;
557 }
558
559 return ret;
560}
561EXPORT_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 */
574int freq_qos_update_request(struct freq_qos_request *req, s32 new_value)
575{
576 if (!req || freq_qos_value_invalid(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, PM_QOS_UPDATE_REQ, new_value);
587}
588EXPORT_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 */
600int 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, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
612 req->qos = NULL;
613 req->type = 0;
614
615 return ret;
616}
617EXPORT_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 */
625int 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(qos) || !notifier)
632 return -EINVAL;
633
634 switch (type) {
635 case FREQ_QOS_MIN:
636 ret = blocking_notifier_chain_register(qos->min_freq.notifiers,
637 notifier);
638 break;
639 case FREQ_QOS_MAX:
640 ret = blocking_notifier_chain_register(qos->max_freq.notifiers,
641 notifier);
642 break;
643 default:
644 WARN_ON(1);
645 ret = -EINVAL;
646 }
647
648 return ret;
649}
650EXPORT_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 */
658int 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(qos) || !notifier)
665 return -EINVAL;
666
667 switch (type) {
668 case FREQ_QOS_MIN:
669 ret = blocking_notifier_chain_unregister(qos->min_freq.notifiers,
670 notifier);
671 break;
672 case FREQ_QOS_MAX:
673 ret = blocking_notifier_chain_unregister(qos->max_freq.notifiers,
674 notifier);
675 break;
676 default:
677 WARN_ON(1);
678 ret = -EINVAL;
679 }
680
681 return ret;
682}
683EXPORT_SYMBOL_GPL(freq_qos_remove_notifier);