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1/*
2 * This module exposes the interface to kernel space for specifying
3 * QoS dependencies. It provides infrastructure for registration of:
4 *
5 * Dependents on a QoS value : register requests
6 * Watchers of QoS value : get notified when target QoS value changes
7 *
8 * This QoS design is best effort based. Dependents register their QoS needs.
9 * Watchers register to keep track of the current QoS needs of the system.
10 *
11 * There are 3 basic classes of QoS parameter: latency, timeout, throughput
12 * each have defined units:
13 * latency: usec
14 * timeout: usec <-- currently not used.
15 * throughput: kbs (kilo byte / sec)
16 *
17 * There are lists of pm_qos_objects each one wrapping requests, notifiers
18 *
19 * User mode requests on a QOS parameter register themselves to the
20 * subsystem by opening the device node /dev/... and writing there request to
21 * the node. As long as the process holds a file handle open to the node the
22 * client continues to be accounted for. Upon file release the usermode
23 * request is removed and a new qos target is computed. This way when the
24 * request that the application has is cleaned up when closes the file
25 * pointer or exits the pm_qos_object will get an opportunity to clean up.
26 *
27 * Mark Gross <mgross@linux.intel.com>
28 */
29
30/*#define DEBUG*/
31
32#include <linux/pm_qos.h>
33#include <linux/sched.h>
34#include <linux/spinlock.h>
35#include <linux/slab.h>
36#include <linux/time.h>
37#include <linux/fs.h>
38#include <linux/device.h>
39#include <linux/miscdevice.h>
40#include <linux/string.h>
41#include <linux/platform_device.h>
42#include <linux/init.h>
43#include <linux/kernel.h>
44#include <linux/debugfs.h>
45#include <linux/seq_file.h>
46
47#include <linux/uaccess.h>
48#include <linux/export.h>
49#include <trace/events/power.h>
50
51/*
52 * locking rule: all changes to constraints or notifiers lists
53 * or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock
54 * held, taken with _irqsave. One lock to rule them all
55 */
56struct pm_qos_object {
57 struct pm_qos_constraints *constraints;
58 struct miscdevice pm_qos_power_miscdev;
59 char *name;
60};
61
62static DEFINE_SPINLOCK(pm_qos_lock);
63
64static struct pm_qos_object null_pm_qos;
65
66static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier);
67static struct pm_qos_constraints cpu_dma_constraints = {
68 .list = PLIST_HEAD_INIT(cpu_dma_constraints.list),
69 .target_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,
70 .default_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,
71 .no_constraint_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,
72 .type = PM_QOS_MIN,
73 .notifiers = &cpu_dma_lat_notifier,
74};
75static struct pm_qos_object cpu_dma_pm_qos = {
76 .constraints = &cpu_dma_constraints,
77 .name = "cpu_dma_latency",
78};
79
80static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);
81static struct pm_qos_constraints network_lat_constraints = {
82 .list = PLIST_HEAD_INIT(network_lat_constraints.list),
83 .target_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE,
84 .default_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE,
85 .no_constraint_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE,
86 .type = PM_QOS_MIN,
87 .notifiers = &network_lat_notifier,
88};
89static struct pm_qos_object network_lat_pm_qos = {
90 .constraints = &network_lat_constraints,
91 .name = "network_latency",
92};
93
94
95static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier);
96static struct pm_qos_constraints network_tput_constraints = {
97 .list = PLIST_HEAD_INIT(network_tput_constraints.list),
98 .target_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE,
99 .default_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE,
100 .no_constraint_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE,
101 .type = PM_QOS_MAX,
102 .notifiers = &network_throughput_notifier,
103};
104static struct pm_qos_object network_throughput_pm_qos = {
105 .constraints = &network_tput_constraints,
106 .name = "network_throughput",
107};
108
109
110static BLOCKING_NOTIFIER_HEAD(memory_bandwidth_notifier);
111static struct pm_qos_constraints memory_bw_constraints = {
112 .list = PLIST_HEAD_INIT(memory_bw_constraints.list),
113 .target_value = PM_QOS_MEMORY_BANDWIDTH_DEFAULT_VALUE,
114 .default_value = PM_QOS_MEMORY_BANDWIDTH_DEFAULT_VALUE,
115 .no_constraint_value = PM_QOS_MEMORY_BANDWIDTH_DEFAULT_VALUE,
116 .type = PM_QOS_SUM,
117 .notifiers = &memory_bandwidth_notifier,
118};
119static struct pm_qos_object memory_bandwidth_pm_qos = {
120 .constraints = &memory_bw_constraints,
121 .name = "memory_bandwidth",
122};
123
124
125static struct pm_qos_object *pm_qos_array[] = {
126 &null_pm_qos,
127 &cpu_dma_pm_qos,
128 &network_lat_pm_qos,
129 &network_throughput_pm_qos,
130 &memory_bandwidth_pm_qos,
131};
132
133static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
134 size_t count, loff_t *f_pos);
135static ssize_t pm_qos_power_read(struct file *filp, char __user *buf,
136 size_t count, loff_t *f_pos);
137static int pm_qos_power_open(struct inode *inode, struct file *filp);
138static int pm_qos_power_release(struct inode *inode, struct file *filp);
139
140static const struct file_operations pm_qos_power_fops = {
141 .write = pm_qos_power_write,
142 .read = pm_qos_power_read,
143 .open = pm_qos_power_open,
144 .release = pm_qos_power_release,
145 .llseek = noop_llseek,
146};
147
148/* unlocked internal variant */
149static inline int pm_qos_get_value(struct pm_qos_constraints *c)
150{
151 struct plist_node *node;
152 int total_value = 0;
153
154 if (plist_head_empty(&c->list))
155 return c->no_constraint_value;
156
157 switch (c->type) {
158 case PM_QOS_MIN:
159 return plist_first(&c->list)->prio;
160
161 case PM_QOS_MAX:
162 return plist_last(&c->list)->prio;
163
164 case PM_QOS_SUM:
165 plist_for_each(node, &c->list)
166 total_value += node->prio;
167
168 return total_value;
169
170 default:
171 /* runtime check for not using enum */
172 BUG();
173 return PM_QOS_DEFAULT_VALUE;
174 }
175}
176
177s32 pm_qos_read_value(struct pm_qos_constraints *c)
178{
179 return c->target_value;
180}
181
182static inline void pm_qos_set_value(struct pm_qos_constraints *c, s32 value)
183{
184 c->target_value = value;
185}
186
187static inline int pm_qos_get_value(struct pm_qos_constraints *c);
188static int pm_qos_dbg_show_requests(struct seq_file *s, void *unused)
189{
190 struct pm_qos_object *qos = (struct pm_qos_object *)s->private;
191 struct pm_qos_constraints *c;
192 struct pm_qos_request *req;
193 char *type;
194 unsigned long flags;
195 int tot_reqs = 0;
196 int active_reqs = 0;
197
198 if (IS_ERR_OR_NULL(qos)) {
199 pr_err("%s: bad qos param!\n", __func__);
200 return -EINVAL;
201 }
202 c = qos->constraints;
203 if (IS_ERR_OR_NULL(c)) {
204 pr_err("%s: Bad constraints on qos?\n", __func__);
205 return -EINVAL;
206 }
207
208 /* Lock to ensure we have a snapshot */
209 spin_lock_irqsave(&pm_qos_lock, flags);
210 if (plist_head_empty(&c->list)) {
211 seq_puts(s, "Empty!\n");
212 goto out;
213 }
214
215 switch (c->type) {
216 case PM_QOS_MIN:
217 type = "Minimum";
218 break;
219 case PM_QOS_MAX:
220 type = "Maximum";
221 break;
222 case PM_QOS_SUM:
223 type = "Sum";
224 break;
225 default:
226 type = "Unknown";
227 }
228
229 plist_for_each_entry(req, &c->list, node) {
230 char *state = "Default";
231
232 if ((req->node).prio != c->default_value) {
233 active_reqs++;
234 state = "Active";
235 }
236 tot_reqs++;
237 seq_printf(s, "%d: %d: %s\n", tot_reqs,
238 (req->node).prio, state);
239 }
240
241 seq_printf(s, "Type=%s, Value=%d, Requests: active=%d / total=%d\n",
242 type, pm_qos_get_value(c), active_reqs, tot_reqs);
243
244out:
245 spin_unlock_irqrestore(&pm_qos_lock, flags);
246 return 0;
247}
248
249static int pm_qos_dbg_open(struct inode *inode, struct file *file)
250{
251 return single_open(file, pm_qos_dbg_show_requests,
252 inode->i_private);
253}
254
255static const struct file_operations pm_qos_debug_fops = {
256 .open = pm_qos_dbg_open,
257 .read = seq_read,
258 .llseek = seq_lseek,
259 .release = single_release,
260};
261
262/**
263 * pm_qos_update_target - manages the constraints list and calls the notifiers
264 * if needed
265 * @c: constraints data struct
266 * @node: request to add to the list, to update or to remove
267 * @action: action to take on the constraints list
268 * @value: value of the request to add or update
269 *
270 * This function returns 1 if the aggregated constraint value has changed, 0
271 * otherwise.
272 */
273int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node,
274 enum pm_qos_req_action action, int value)
275{
276 unsigned long flags;
277 int prev_value, curr_value, new_value;
278 int ret;
279
280 spin_lock_irqsave(&pm_qos_lock, flags);
281 prev_value = pm_qos_get_value(c);
282 if (value == PM_QOS_DEFAULT_VALUE)
283 new_value = c->default_value;
284 else
285 new_value = value;
286
287 switch (action) {
288 case PM_QOS_REMOVE_REQ:
289 plist_del(node, &c->list);
290 break;
291 case PM_QOS_UPDATE_REQ:
292 /*
293 * to change the list, we atomically remove, reinit
294 * with new value and add, then see if the extremal
295 * changed
296 */
297 plist_del(node, &c->list);
298 case PM_QOS_ADD_REQ:
299 plist_node_init(node, new_value);
300 plist_add(node, &c->list);
301 break;
302 default:
303 /* no action */
304 ;
305 }
306
307 curr_value = pm_qos_get_value(c);
308 pm_qos_set_value(c, curr_value);
309
310 spin_unlock_irqrestore(&pm_qos_lock, flags);
311
312 trace_pm_qos_update_target(action, prev_value, curr_value);
313 if (prev_value != curr_value) {
314 ret = 1;
315 if (c->notifiers)
316 blocking_notifier_call_chain(c->notifiers,
317 (unsigned long)curr_value,
318 NULL);
319 } else {
320 ret = 0;
321 }
322 return ret;
323}
324
325/**
326 * pm_qos_flags_remove_req - Remove device PM QoS flags request.
327 * @pqf: Device PM QoS flags set to remove the request from.
328 * @req: Request to remove from the set.
329 */
330static void pm_qos_flags_remove_req(struct pm_qos_flags *pqf,
331 struct pm_qos_flags_request *req)
332{
333 s32 val = 0;
334
335 list_del(&req->node);
336 list_for_each_entry(req, &pqf->list, node)
337 val |= req->flags;
338
339 pqf->effective_flags = val;
340}
341
342/**
343 * pm_qos_update_flags - Update a set of PM QoS flags.
344 * @pqf: Set of flags to update.
345 * @req: Request to add to the set, to modify, or to remove from the set.
346 * @action: Action to take on the set.
347 * @val: Value of the request to add or modify.
348 *
349 * Update the given set of PM QoS flags and call notifiers if the aggregate
350 * value has changed. Returns 1 if the aggregate constraint value has changed,
351 * 0 otherwise.
352 */
353bool pm_qos_update_flags(struct pm_qos_flags *pqf,
354 struct pm_qos_flags_request *req,
355 enum pm_qos_req_action action, s32 val)
356{
357 unsigned long irqflags;
358 s32 prev_value, curr_value;
359
360 spin_lock_irqsave(&pm_qos_lock, irqflags);
361
362 prev_value = list_empty(&pqf->list) ? 0 : pqf->effective_flags;
363
364 switch (action) {
365 case PM_QOS_REMOVE_REQ:
366 pm_qos_flags_remove_req(pqf, req);
367 break;
368 case PM_QOS_UPDATE_REQ:
369 pm_qos_flags_remove_req(pqf, req);
370 case PM_QOS_ADD_REQ:
371 req->flags = val;
372 INIT_LIST_HEAD(&req->node);
373 list_add_tail(&req->node, &pqf->list);
374 pqf->effective_flags |= val;
375 break;
376 default:
377 /* no action */
378 ;
379 }
380
381 curr_value = list_empty(&pqf->list) ? 0 : pqf->effective_flags;
382
383 spin_unlock_irqrestore(&pm_qos_lock, irqflags);
384
385 trace_pm_qos_update_flags(action, prev_value, curr_value);
386 return prev_value != curr_value;
387}
388
389/**
390 * pm_qos_request - returns current system wide qos expectation
391 * @pm_qos_class: identification of which qos value is requested
392 *
393 * This function returns the current target value.
394 */
395int pm_qos_request(int pm_qos_class)
396{
397 return pm_qos_read_value(pm_qos_array[pm_qos_class]->constraints);
398}
399EXPORT_SYMBOL_GPL(pm_qos_request);
400
401int pm_qos_request_active(struct pm_qos_request *req)
402{
403 return req->pm_qos_class != 0;
404}
405EXPORT_SYMBOL_GPL(pm_qos_request_active);
406
407static void __pm_qos_update_request(struct pm_qos_request *req,
408 s32 new_value)
409{
410 trace_pm_qos_update_request(req->pm_qos_class, new_value);
411
412 if (new_value != req->node.prio)
413 pm_qos_update_target(
414 pm_qos_array[req->pm_qos_class]->constraints,
415 &req->node, PM_QOS_UPDATE_REQ, new_value);
416}
417
418/**
419 * pm_qos_work_fn - the timeout handler of pm_qos_update_request_timeout
420 * @work: work struct for the delayed work (timeout)
421 *
422 * This cancels the timeout request by falling back to the default at timeout.
423 */
424static void pm_qos_work_fn(struct work_struct *work)
425{
426 struct pm_qos_request *req = container_of(to_delayed_work(work),
427 struct pm_qos_request,
428 work);
429
430 __pm_qos_update_request(req, PM_QOS_DEFAULT_VALUE);
431}
432
433/**
434 * pm_qos_add_request - inserts new qos request into the list
435 * @req: pointer to a preallocated handle
436 * @pm_qos_class: identifies which list of qos request to use
437 * @value: defines the qos request
438 *
439 * This function inserts a new entry in the pm_qos_class list of requested qos
440 * performance characteristics. It recomputes the aggregate QoS expectations
441 * for the pm_qos_class of parameters and initializes the pm_qos_request
442 * handle. Caller needs to save this handle for later use in updates and
443 * removal.
444 */
445
446void pm_qos_add_request(struct pm_qos_request *req,
447 int pm_qos_class, s32 value)
448{
449 if (!req) /*guard against callers passing in null */
450 return;
451
452 if (pm_qos_request_active(req)) {
453 WARN(1, KERN_ERR "pm_qos_add_request() called for already added request\n");
454 return;
455 }
456 req->pm_qos_class = pm_qos_class;
457 INIT_DELAYED_WORK(&req->work, pm_qos_work_fn);
458 trace_pm_qos_add_request(pm_qos_class, value);
459 pm_qos_update_target(pm_qos_array[pm_qos_class]->constraints,
460 &req->node, PM_QOS_ADD_REQ, value);
461}
462EXPORT_SYMBOL_GPL(pm_qos_add_request);
463
464/**
465 * pm_qos_update_request - modifies an existing qos request
466 * @req : handle to list element holding a pm_qos request to use
467 * @value: defines the qos request
468 *
469 * Updates an existing qos request for the pm_qos_class of parameters along
470 * with updating the target pm_qos_class value.
471 *
472 * Attempts are made to make this code callable on hot code paths.
473 */
474void pm_qos_update_request(struct pm_qos_request *req,
475 s32 new_value)
476{
477 if (!req) /*guard against callers passing in null */
478 return;
479
480 if (!pm_qos_request_active(req)) {
481 WARN(1, KERN_ERR "pm_qos_update_request() called for unknown object\n");
482 return;
483 }
484
485 cancel_delayed_work_sync(&req->work);
486 __pm_qos_update_request(req, new_value);
487}
488EXPORT_SYMBOL_GPL(pm_qos_update_request);
489
490/**
491 * pm_qos_update_request_timeout - modifies an existing qos request temporarily.
492 * @req : handle to list element holding a pm_qos request to use
493 * @new_value: defines the temporal qos request
494 * @timeout_us: the effective duration of this qos request in usecs.
495 *
496 * After timeout_us, this qos request is cancelled automatically.
497 */
498void pm_qos_update_request_timeout(struct pm_qos_request *req, s32 new_value,
499 unsigned long timeout_us)
500{
501 if (!req)
502 return;
503 if (WARN(!pm_qos_request_active(req),
504 "%s called for unknown object.", __func__))
505 return;
506
507 cancel_delayed_work_sync(&req->work);
508
509 trace_pm_qos_update_request_timeout(req->pm_qos_class,
510 new_value, timeout_us);
511 if (new_value != req->node.prio)
512 pm_qos_update_target(
513 pm_qos_array[req->pm_qos_class]->constraints,
514 &req->node, PM_QOS_UPDATE_REQ, new_value);
515
516 schedule_delayed_work(&req->work, usecs_to_jiffies(timeout_us));
517}
518
519/**
520 * pm_qos_remove_request - modifies an existing qos request
521 * @req: handle to request list element
522 *
523 * Will remove pm qos request from the list of constraints and
524 * recompute the current target value for the pm_qos_class. Call this
525 * on slow code paths.
526 */
527void pm_qos_remove_request(struct pm_qos_request *req)
528{
529 if (!req) /*guard against callers passing in null */
530 return;
531 /* silent return to keep pcm code cleaner */
532
533 if (!pm_qos_request_active(req)) {
534 WARN(1, KERN_ERR "pm_qos_remove_request() called for unknown object\n");
535 return;
536 }
537
538 cancel_delayed_work_sync(&req->work);
539
540 trace_pm_qos_remove_request(req->pm_qos_class, PM_QOS_DEFAULT_VALUE);
541 pm_qos_update_target(pm_qos_array[req->pm_qos_class]->constraints,
542 &req->node, PM_QOS_REMOVE_REQ,
543 PM_QOS_DEFAULT_VALUE);
544 memset(req, 0, sizeof(*req));
545}
546EXPORT_SYMBOL_GPL(pm_qos_remove_request);
547
548/**
549 * pm_qos_add_notifier - sets notification entry for changes to target value
550 * @pm_qos_class: identifies which qos target changes should be notified.
551 * @notifier: notifier block managed by caller.
552 *
553 * will register the notifier into a notification chain that gets called
554 * upon changes to the pm_qos_class target value.
555 */
556int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
557{
558 int retval;
559
560 retval = blocking_notifier_chain_register(
561 pm_qos_array[pm_qos_class]->constraints->notifiers,
562 notifier);
563
564 return retval;
565}
566EXPORT_SYMBOL_GPL(pm_qos_add_notifier);
567
568/**
569 * pm_qos_remove_notifier - deletes notification entry from chain.
570 * @pm_qos_class: identifies which qos target changes are notified.
571 * @notifier: notifier block to be removed.
572 *
573 * will remove the notifier from the notification chain that gets called
574 * upon changes to the pm_qos_class target value.
575 */
576int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
577{
578 int retval;
579
580 retval = blocking_notifier_chain_unregister(
581 pm_qos_array[pm_qos_class]->constraints->notifiers,
582 notifier);
583
584 return retval;
585}
586EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);
587
588/* User space interface to PM QoS classes via misc devices */
589static int register_pm_qos_misc(struct pm_qos_object *qos, struct dentry *d)
590{
591 qos->pm_qos_power_miscdev.minor = MISC_DYNAMIC_MINOR;
592 qos->pm_qos_power_miscdev.name = qos->name;
593 qos->pm_qos_power_miscdev.fops = &pm_qos_power_fops;
594
595 if (d) {
596 (void)debugfs_create_file(qos->name, S_IRUGO, d,
597 (void *)qos, &pm_qos_debug_fops);
598 }
599
600 return misc_register(&qos->pm_qos_power_miscdev);
601}
602
603static int find_pm_qos_object_by_minor(int minor)
604{
605 int pm_qos_class;
606
607 for (pm_qos_class = PM_QOS_CPU_DMA_LATENCY;
608 pm_qos_class < PM_QOS_NUM_CLASSES; pm_qos_class++) {
609 if (minor ==
610 pm_qos_array[pm_qos_class]->pm_qos_power_miscdev.minor)
611 return pm_qos_class;
612 }
613 return -1;
614}
615
616static int pm_qos_power_open(struct inode *inode, struct file *filp)
617{
618 long pm_qos_class;
619
620 pm_qos_class = find_pm_qos_object_by_minor(iminor(inode));
621 if (pm_qos_class >= PM_QOS_CPU_DMA_LATENCY) {
622 struct pm_qos_request *req = kzalloc(sizeof(*req), GFP_KERNEL);
623 if (!req)
624 return -ENOMEM;
625
626 pm_qos_add_request(req, pm_qos_class, PM_QOS_DEFAULT_VALUE);
627 filp->private_data = req;
628
629 return 0;
630 }
631 return -EPERM;
632}
633
634static int pm_qos_power_release(struct inode *inode, struct file *filp)
635{
636 struct pm_qos_request *req;
637
638 req = filp->private_data;
639 pm_qos_remove_request(req);
640 kfree(req);
641
642 return 0;
643}
644
645
646static ssize_t pm_qos_power_read(struct file *filp, char __user *buf,
647 size_t count, loff_t *f_pos)
648{
649 s32 value;
650 unsigned long flags;
651 struct pm_qos_request *req = filp->private_data;
652
653 if (!req)
654 return -EINVAL;
655 if (!pm_qos_request_active(req))
656 return -EINVAL;
657
658 spin_lock_irqsave(&pm_qos_lock, flags);
659 value = pm_qos_get_value(pm_qos_array[req->pm_qos_class]->constraints);
660 spin_unlock_irqrestore(&pm_qos_lock, flags);
661
662 return simple_read_from_buffer(buf, count, f_pos, &value, sizeof(s32));
663}
664
665static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
666 size_t count, loff_t *f_pos)
667{
668 s32 value;
669 struct pm_qos_request *req;
670
671 if (count == sizeof(s32)) {
672 if (copy_from_user(&value, buf, sizeof(s32)))
673 return -EFAULT;
674 } else {
675 int ret;
676
677 ret = kstrtos32_from_user(buf, count, 16, &value);
678 if (ret)
679 return ret;
680 }
681
682 req = filp->private_data;
683 pm_qos_update_request(req, value);
684
685 return count;
686}
687
688
689static int __init pm_qos_power_init(void)
690{
691 int ret = 0;
692 int i;
693 struct dentry *d;
694
695 BUILD_BUG_ON(ARRAY_SIZE(pm_qos_array) != PM_QOS_NUM_CLASSES);
696
697 d = debugfs_create_dir("pm_qos", NULL);
698 if (IS_ERR_OR_NULL(d))
699 d = NULL;
700
701 for (i = PM_QOS_CPU_DMA_LATENCY; i < PM_QOS_NUM_CLASSES; i++) {
702 ret = register_pm_qos_misc(pm_qos_array[i], d);
703 if (ret < 0) {
704 printk(KERN_ERR "pm_qos_param: %s setup failed\n",
705 pm_qos_array[i]->name);
706 return ret;
707 }
708 }
709
710 return ret;
711}
712
713late_initcall(pm_qos_power_init);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * This module exposes the interface to kernel space for specifying
4 * QoS dependencies. It provides infrastructure for registration of:
5 *
6 * Dependents on a QoS value : register requests
7 * Watchers of QoS value : get notified when target QoS value changes
8 *
9 * This QoS design is best effort based. Dependents register their QoS needs.
10 * Watchers register to keep track of the current QoS needs of the system.
11 *
12 * There are 3 basic classes of QoS parameter: latency, timeout, throughput
13 * each have defined units:
14 * latency: usec
15 * timeout: usec <-- currently not used.
16 * throughput: kbs (kilo byte / sec)
17 *
18 * There are lists of pm_qos_objects each one wrapping requests, notifiers
19 *
20 * User mode requests on a QOS parameter register themselves to the
21 * subsystem by opening the device node /dev/... and writing there request to
22 * the node. As long as the process holds a file handle open to the node the
23 * client continues to be accounted for. Upon file release the usermode
24 * request is removed and a new qos target is computed. This way when the
25 * request that the application has is cleaned up when closes the file
26 * pointer or exits the pm_qos_object will get an opportunity to clean up.
27 *
28 * Mark Gross <mgross@linux.intel.com>
29 */
30
31/*#define DEBUG*/
32
33#include <linux/pm_qos.h>
34#include <linux/sched.h>
35#include <linux/spinlock.h>
36#include <linux/slab.h>
37#include <linux/time.h>
38#include <linux/fs.h>
39#include <linux/device.h>
40#include <linux/miscdevice.h>
41#include <linux/string.h>
42#include <linux/platform_device.h>
43#include <linux/init.h>
44#include <linux/kernel.h>
45#include <linux/debugfs.h>
46#include <linux/seq_file.h>
47
48#include <linux/uaccess.h>
49#include <linux/export.h>
50#include <trace/events/power.h>
51
52/*
53 * locking rule: all changes to constraints or notifiers lists
54 * or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock
55 * held, taken with _irqsave. One lock to rule them all
56 */
57struct pm_qos_object {
58 struct pm_qos_constraints *constraints;
59 struct miscdevice pm_qos_power_miscdev;
60 char *name;
61};
62
63static DEFINE_SPINLOCK(pm_qos_lock);
64
65static struct pm_qos_object null_pm_qos;
66
67static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier);
68static struct pm_qos_constraints cpu_dma_constraints = {
69 .list = PLIST_HEAD_INIT(cpu_dma_constraints.list),
70 .target_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,
71 .default_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,
72 .no_constraint_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,
73 .type = PM_QOS_MIN,
74 .notifiers = &cpu_dma_lat_notifier,
75};
76static struct pm_qos_object cpu_dma_pm_qos = {
77 .constraints = &cpu_dma_constraints,
78 .name = "cpu_dma_latency",
79};
80
81static struct pm_qos_object *pm_qos_array[] = {
82 &null_pm_qos,
83 &cpu_dma_pm_qos,
84};
85
86static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
87 size_t count, loff_t *f_pos);
88static ssize_t pm_qos_power_read(struct file *filp, char __user *buf,
89 size_t count, loff_t *f_pos);
90static int pm_qos_power_open(struct inode *inode, struct file *filp);
91static int pm_qos_power_release(struct inode *inode, struct file *filp);
92
93static const struct file_operations pm_qos_power_fops = {
94 .write = pm_qos_power_write,
95 .read = pm_qos_power_read,
96 .open = pm_qos_power_open,
97 .release = pm_qos_power_release,
98 .llseek = noop_llseek,
99};
100
101/* unlocked internal variant */
102static inline int pm_qos_get_value(struct pm_qos_constraints *c)
103{
104 struct plist_node *node;
105 int total_value = 0;
106
107 if (plist_head_empty(&c->list))
108 return c->no_constraint_value;
109
110 switch (c->type) {
111 case PM_QOS_MIN:
112 return plist_first(&c->list)->prio;
113
114 case PM_QOS_MAX:
115 return plist_last(&c->list)->prio;
116
117 case PM_QOS_SUM:
118 plist_for_each(node, &c->list)
119 total_value += node->prio;
120
121 return total_value;
122
123 default:
124 /* runtime check for not using enum */
125 BUG();
126 return PM_QOS_DEFAULT_VALUE;
127 }
128}
129
130s32 pm_qos_read_value(struct pm_qos_constraints *c)
131{
132 return c->target_value;
133}
134
135static inline void pm_qos_set_value(struct pm_qos_constraints *c, s32 value)
136{
137 c->target_value = value;
138}
139
140static int pm_qos_debug_show(struct seq_file *s, void *unused)
141{
142 struct pm_qos_object *qos = (struct pm_qos_object *)s->private;
143 struct pm_qos_constraints *c;
144 struct pm_qos_request *req;
145 char *type;
146 unsigned long flags;
147 int tot_reqs = 0;
148 int active_reqs = 0;
149
150 if (IS_ERR_OR_NULL(qos)) {
151 pr_err("%s: bad qos param!\n", __func__);
152 return -EINVAL;
153 }
154 c = qos->constraints;
155 if (IS_ERR_OR_NULL(c)) {
156 pr_err("%s: Bad constraints on qos?\n", __func__);
157 return -EINVAL;
158 }
159
160 /* Lock to ensure we have a snapshot */
161 spin_lock_irqsave(&pm_qos_lock, flags);
162 if (plist_head_empty(&c->list)) {
163 seq_puts(s, "Empty!\n");
164 goto out;
165 }
166
167 switch (c->type) {
168 case PM_QOS_MIN:
169 type = "Minimum";
170 break;
171 case PM_QOS_MAX:
172 type = "Maximum";
173 break;
174 case PM_QOS_SUM:
175 type = "Sum";
176 break;
177 default:
178 type = "Unknown";
179 }
180
181 plist_for_each_entry(req, &c->list, node) {
182 char *state = "Default";
183
184 if ((req->node).prio != c->default_value) {
185 active_reqs++;
186 state = "Active";
187 }
188 tot_reqs++;
189 seq_printf(s, "%d: %d: %s\n", tot_reqs,
190 (req->node).prio, state);
191 }
192
193 seq_printf(s, "Type=%s, Value=%d, Requests: active=%d / total=%d\n",
194 type, pm_qos_get_value(c), active_reqs, tot_reqs);
195
196out:
197 spin_unlock_irqrestore(&pm_qos_lock, flags);
198 return 0;
199}
200
201DEFINE_SHOW_ATTRIBUTE(pm_qos_debug);
202
203/**
204 * pm_qos_update_target - manages the constraints list and calls the notifiers
205 * if needed
206 * @c: constraints data struct
207 * @node: request to add to the list, to update or to remove
208 * @action: action to take on the constraints list
209 * @value: value of the request to add or update
210 *
211 * This function returns 1 if the aggregated constraint value has changed, 0
212 * otherwise.
213 */
214int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node,
215 enum pm_qos_req_action action, int value)
216{
217 unsigned long flags;
218 int prev_value, curr_value, new_value;
219 int ret;
220
221 spin_lock_irqsave(&pm_qos_lock, flags);
222 prev_value = pm_qos_get_value(c);
223 if (value == PM_QOS_DEFAULT_VALUE)
224 new_value = c->default_value;
225 else
226 new_value = value;
227
228 switch (action) {
229 case PM_QOS_REMOVE_REQ:
230 plist_del(node, &c->list);
231 break;
232 case PM_QOS_UPDATE_REQ:
233 /*
234 * to change the list, we atomically remove, reinit
235 * with new value and add, then see if the extremal
236 * changed
237 */
238 plist_del(node, &c->list);
239 /* fall through */
240 case PM_QOS_ADD_REQ:
241 plist_node_init(node, new_value);
242 plist_add(node, &c->list);
243 break;
244 default:
245 /* no action */
246 ;
247 }
248
249 curr_value = pm_qos_get_value(c);
250 pm_qos_set_value(c, curr_value);
251
252 spin_unlock_irqrestore(&pm_qos_lock, flags);
253
254 trace_pm_qos_update_target(action, prev_value, curr_value);
255 if (prev_value != curr_value) {
256 ret = 1;
257 if (c->notifiers)
258 blocking_notifier_call_chain(c->notifiers,
259 (unsigned long)curr_value,
260 NULL);
261 } else {
262 ret = 0;
263 }
264 return ret;
265}
266
267/**
268 * pm_qos_flags_remove_req - Remove device PM QoS flags request.
269 * @pqf: Device PM QoS flags set to remove the request from.
270 * @req: Request to remove from the set.
271 */
272static void pm_qos_flags_remove_req(struct pm_qos_flags *pqf,
273 struct pm_qos_flags_request *req)
274{
275 s32 val = 0;
276
277 list_del(&req->node);
278 list_for_each_entry(req, &pqf->list, node)
279 val |= req->flags;
280
281 pqf->effective_flags = val;
282}
283
284/**
285 * pm_qos_update_flags - Update a set of PM QoS flags.
286 * @pqf: Set of flags to update.
287 * @req: Request to add to the set, to modify, or to remove from the set.
288 * @action: Action to take on the set.
289 * @val: Value of the request to add or modify.
290 *
291 * Update the given set of PM QoS flags and call notifiers if the aggregate
292 * value has changed. Returns 1 if the aggregate constraint value has changed,
293 * 0 otherwise.
294 */
295bool pm_qos_update_flags(struct pm_qos_flags *pqf,
296 struct pm_qos_flags_request *req,
297 enum pm_qos_req_action action, s32 val)
298{
299 unsigned long irqflags;
300 s32 prev_value, curr_value;
301
302 spin_lock_irqsave(&pm_qos_lock, irqflags);
303
304 prev_value = list_empty(&pqf->list) ? 0 : pqf->effective_flags;
305
306 switch (action) {
307 case PM_QOS_REMOVE_REQ:
308 pm_qos_flags_remove_req(pqf, req);
309 break;
310 case PM_QOS_UPDATE_REQ:
311 pm_qos_flags_remove_req(pqf, req);
312 /* fall through */
313 case PM_QOS_ADD_REQ:
314 req->flags = val;
315 INIT_LIST_HEAD(&req->node);
316 list_add_tail(&req->node, &pqf->list);
317 pqf->effective_flags |= val;
318 break;
319 default:
320 /* no action */
321 ;
322 }
323
324 curr_value = list_empty(&pqf->list) ? 0 : pqf->effective_flags;
325
326 spin_unlock_irqrestore(&pm_qos_lock, irqflags);
327
328 trace_pm_qos_update_flags(action, prev_value, curr_value);
329 return prev_value != curr_value;
330}
331
332/**
333 * pm_qos_request - returns current system wide qos expectation
334 * @pm_qos_class: identification of which qos value is requested
335 *
336 * This function returns the current target value.
337 */
338int pm_qos_request(int pm_qos_class)
339{
340 return pm_qos_read_value(pm_qos_array[pm_qos_class]->constraints);
341}
342EXPORT_SYMBOL_GPL(pm_qos_request);
343
344int pm_qos_request_active(struct pm_qos_request *req)
345{
346 return req->pm_qos_class != 0;
347}
348EXPORT_SYMBOL_GPL(pm_qos_request_active);
349
350static void __pm_qos_update_request(struct pm_qos_request *req,
351 s32 new_value)
352{
353 trace_pm_qos_update_request(req->pm_qos_class, new_value);
354
355 if (new_value != req->node.prio)
356 pm_qos_update_target(
357 pm_qos_array[req->pm_qos_class]->constraints,
358 &req->node, PM_QOS_UPDATE_REQ, new_value);
359}
360
361/**
362 * pm_qos_work_fn - the timeout handler of pm_qos_update_request_timeout
363 * @work: work struct for the delayed work (timeout)
364 *
365 * This cancels the timeout request by falling back to the default at timeout.
366 */
367static void pm_qos_work_fn(struct work_struct *work)
368{
369 struct pm_qos_request *req = container_of(to_delayed_work(work),
370 struct pm_qos_request,
371 work);
372
373 __pm_qos_update_request(req, PM_QOS_DEFAULT_VALUE);
374}
375
376/**
377 * pm_qos_add_request - inserts new qos request into the list
378 * @req: pointer to a preallocated handle
379 * @pm_qos_class: identifies which list of qos request to use
380 * @value: defines the qos request
381 *
382 * This function inserts a new entry in the pm_qos_class list of requested qos
383 * performance characteristics. It recomputes the aggregate QoS expectations
384 * for the pm_qos_class of parameters and initializes the pm_qos_request
385 * handle. Caller needs to save this handle for later use in updates and
386 * removal.
387 */
388
389void pm_qos_add_request(struct pm_qos_request *req,
390 int pm_qos_class, s32 value)
391{
392 if (!req) /*guard against callers passing in null */
393 return;
394
395 if (pm_qos_request_active(req)) {
396 WARN(1, KERN_ERR "pm_qos_add_request() called for already added request\n");
397 return;
398 }
399 req->pm_qos_class = pm_qos_class;
400 INIT_DELAYED_WORK(&req->work, pm_qos_work_fn);
401 trace_pm_qos_add_request(pm_qos_class, value);
402 pm_qos_update_target(pm_qos_array[pm_qos_class]->constraints,
403 &req->node, PM_QOS_ADD_REQ, value);
404}
405EXPORT_SYMBOL_GPL(pm_qos_add_request);
406
407/**
408 * pm_qos_update_request - modifies an existing qos request
409 * @req : handle to list element holding a pm_qos request to use
410 * @value: defines the qos request
411 *
412 * Updates an existing qos request for the pm_qos_class of parameters along
413 * with updating the target pm_qos_class value.
414 *
415 * Attempts are made to make this code callable on hot code paths.
416 */
417void pm_qos_update_request(struct pm_qos_request *req,
418 s32 new_value)
419{
420 if (!req) /*guard against callers passing in null */
421 return;
422
423 if (!pm_qos_request_active(req)) {
424 WARN(1, KERN_ERR "pm_qos_update_request() called for unknown object\n");
425 return;
426 }
427
428 cancel_delayed_work_sync(&req->work);
429 __pm_qos_update_request(req, new_value);
430}
431EXPORT_SYMBOL_GPL(pm_qos_update_request);
432
433/**
434 * pm_qos_update_request_timeout - modifies an existing qos request temporarily.
435 * @req : handle to list element holding a pm_qos request to use
436 * @new_value: defines the temporal qos request
437 * @timeout_us: the effective duration of this qos request in usecs.
438 *
439 * After timeout_us, this qos request is cancelled automatically.
440 */
441void pm_qos_update_request_timeout(struct pm_qos_request *req, s32 new_value,
442 unsigned long timeout_us)
443{
444 if (!req)
445 return;
446 if (WARN(!pm_qos_request_active(req),
447 "%s called for unknown object.", __func__))
448 return;
449
450 cancel_delayed_work_sync(&req->work);
451
452 trace_pm_qos_update_request_timeout(req->pm_qos_class,
453 new_value, timeout_us);
454 if (new_value != req->node.prio)
455 pm_qos_update_target(
456 pm_qos_array[req->pm_qos_class]->constraints,
457 &req->node, PM_QOS_UPDATE_REQ, new_value);
458
459 schedule_delayed_work(&req->work, usecs_to_jiffies(timeout_us));
460}
461
462/**
463 * pm_qos_remove_request - modifies an existing qos request
464 * @req: handle to request list element
465 *
466 * Will remove pm qos request from the list of constraints and
467 * recompute the current target value for the pm_qos_class. Call this
468 * on slow code paths.
469 */
470void pm_qos_remove_request(struct pm_qos_request *req)
471{
472 if (!req) /*guard against callers passing in null */
473 return;
474 /* silent return to keep pcm code cleaner */
475
476 if (!pm_qos_request_active(req)) {
477 WARN(1, KERN_ERR "pm_qos_remove_request() called for unknown object\n");
478 return;
479 }
480
481 cancel_delayed_work_sync(&req->work);
482
483 trace_pm_qos_remove_request(req->pm_qos_class, PM_QOS_DEFAULT_VALUE);
484 pm_qos_update_target(pm_qos_array[req->pm_qos_class]->constraints,
485 &req->node, PM_QOS_REMOVE_REQ,
486 PM_QOS_DEFAULT_VALUE);
487 memset(req, 0, sizeof(*req));
488}
489EXPORT_SYMBOL_GPL(pm_qos_remove_request);
490
491/**
492 * pm_qos_add_notifier - sets notification entry for changes to target value
493 * @pm_qos_class: identifies which qos target changes should be notified.
494 * @notifier: notifier block managed by caller.
495 *
496 * will register the notifier into a notification chain that gets called
497 * upon changes to the pm_qos_class target value.
498 */
499int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
500{
501 int retval;
502
503 retval = blocking_notifier_chain_register(
504 pm_qos_array[pm_qos_class]->constraints->notifiers,
505 notifier);
506
507 return retval;
508}
509EXPORT_SYMBOL_GPL(pm_qos_add_notifier);
510
511/**
512 * pm_qos_remove_notifier - deletes notification entry from chain.
513 * @pm_qos_class: identifies which qos target changes are notified.
514 * @notifier: notifier block to be removed.
515 *
516 * will remove the notifier from the notification chain that gets called
517 * upon changes to the pm_qos_class target value.
518 */
519int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
520{
521 int retval;
522
523 retval = blocking_notifier_chain_unregister(
524 pm_qos_array[pm_qos_class]->constraints->notifiers,
525 notifier);
526
527 return retval;
528}
529EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);
530
531/* User space interface to PM QoS classes via misc devices */
532static int register_pm_qos_misc(struct pm_qos_object *qos, struct dentry *d)
533{
534 qos->pm_qos_power_miscdev.minor = MISC_DYNAMIC_MINOR;
535 qos->pm_qos_power_miscdev.name = qos->name;
536 qos->pm_qos_power_miscdev.fops = &pm_qos_power_fops;
537
538 debugfs_create_file(qos->name, S_IRUGO, d, (void *)qos,
539 &pm_qos_debug_fops);
540
541 return misc_register(&qos->pm_qos_power_miscdev);
542}
543
544static int find_pm_qos_object_by_minor(int minor)
545{
546 int pm_qos_class;
547
548 for (pm_qos_class = PM_QOS_CPU_DMA_LATENCY;
549 pm_qos_class < PM_QOS_NUM_CLASSES; pm_qos_class++) {
550 if (minor ==
551 pm_qos_array[pm_qos_class]->pm_qos_power_miscdev.minor)
552 return pm_qos_class;
553 }
554 return -1;
555}
556
557static int pm_qos_power_open(struct inode *inode, struct file *filp)
558{
559 long pm_qos_class;
560
561 pm_qos_class = find_pm_qos_object_by_minor(iminor(inode));
562 if (pm_qos_class >= PM_QOS_CPU_DMA_LATENCY) {
563 struct pm_qos_request *req = kzalloc(sizeof(*req), GFP_KERNEL);
564 if (!req)
565 return -ENOMEM;
566
567 pm_qos_add_request(req, pm_qos_class, PM_QOS_DEFAULT_VALUE);
568 filp->private_data = req;
569
570 return 0;
571 }
572 return -EPERM;
573}
574
575static int pm_qos_power_release(struct inode *inode, struct file *filp)
576{
577 struct pm_qos_request *req;
578
579 req = filp->private_data;
580 pm_qos_remove_request(req);
581 kfree(req);
582
583 return 0;
584}
585
586
587static ssize_t pm_qos_power_read(struct file *filp, char __user *buf,
588 size_t count, loff_t *f_pos)
589{
590 s32 value;
591 unsigned long flags;
592 struct pm_qos_request *req = filp->private_data;
593
594 if (!req)
595 return -EINVAL;
596 if (!pm_qos_request_active(req))
597 return -EINVAL;
598
599 spin_lock_irqsave(&pm_qos_lock, flags);
600 value = pm_qos_get_value(pm_qos_array[req->pm_qos_class]->constraints);
601 spin_unlock_irqrestore(&pm_qos_lock, flags);
602
603 return simple_read_from_buffer(buf, count, f_pos, &value, sizeof(s32));
604}
605
606static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
607 size_t count, loff_t *f_pos)
608{
609 s32 value;
610 struct pm_qos_request *req;
611
612 if (count == sizeof(s32)) {
613 if (copy_from_user(&value, buf, sizeof(s32)))
614 return -EFAULT;
615 } else {
616 int ret;
617
618 ret = kstrtos32_from_user(buf, count, 16, &value);
619 if (ret)
620 return ret;
621 }
622
623 req = filp->private_data;
624 pm_qos_update_request(req, value);
625
626 return count;
627}
628
629
630static int __init pm_qos_power_init(void)
631{
632 int ret = 0;
633 int i;
634 struct dentry *d;
635
636 BUILD_BUG_ON(ARRAY_SIZE(pm_qos_array) != PM_QOS_NUM_CLASSES);
637
638 d = debugfs_create_dir("pm_qos", NULL);
639
640 for (i = PM_QOS_CPU_DMA_LATENCY; i < PM_QOS_NUM_CLASSES; i++) {
641 ret = register_pm_qos_misc(pm_qos_array[i], d);
642 if (ret < 0) {
643 pr_err("%s: %s setup failed\n",
644 __func__, pm_qos_array[i]->name);
645 return ret;
646 }
647 }
648
649 return ret;
650}
651
652late_initcall(pm_qos_power_init);
653
654/* Definitions related to the frequency QoS below. */
655
656/**
657 * freq_constraints_init - Initialize frequency QoS constraints.
658 * @qos: Frequency QoS constraints to initialize.
659 */
660void freq_constraints_init(struct freq_constraints *qos)
661{
662 struct pm_qos_constraints *c;
663
664 c = &qos->min_freq;
665 plist_head_init(&c->list);
666 c->target_value = FREQ_QOS_MIN_DEFAULT_VALUE;
667 c->default_value = FREQ_QOS_MIN_DEFAULT_VALUE;
668 c->no_constraint_value = FREQ_QOS_MIN_DEFAULT_VALUE;
669 c->type = PM_QOS_MAX;
670 c->notifiers = &qos->min_freq_notifiers;
671 BLOCKING_INIT_NOTIFIER_HEAD(c->notifiers);
672
673 c = &qos->max_freq;
674 plist_head_init(&c->list);
675 c->target_value = FREQ_QOS_MAX_DEFAULT_VALUE;
676 c->default_value = FREQ_QOS_MAX_DEFAULT_VALUE;
677 c->no_constraint_value = FREQ_QOS_MAX_DEFAULT_VALUE;
678 c->type = PM_QOS_MIN;
679 c->notifiers = &qos->max_freq_notifiers;
680 BLOCKING_INIT_NOTIFIER_HEAD(c->notifiers);
681}
682
683/**
684 * freq_qos_read_value - Get frequency QoS constraint for a given list.
685 * @qos: Constraints to evaluate.
686 * @type: QoS request type.
687 */
688s32 freq_qos_read_value(struct freq_constraints *qos,
689 enum freq_qos_req_type type)
690{
691 s32 ret;
692
693 switch (type) {
694 case FREQ_QOS_MIN:
695 ret = IS_ERR_OR_NULL(qos) ?
696 FREQ_QOS_MIN_DEFAULT_VALUE :
697 pm_qos_read_value(&qos->min_freq);
698 break;
699 case FREQ_QOS_MAX:
700 ret = IS_ERR_OR_NULL(qos) ?
701 FREQ_QOS_MAX_DEFAULT_VALUE :
702 pm_qos_read_value(&qos->max_freq);
703 break;
704 default:
705 WARN_ON(1);
706 ret = 0;
707 }
708
709 return ret;
710}
711
712/**
713 * freq_qos_apply - Add/modify/remove frequency QoS request.
714 * @req: Constraint request to apply.
715 * @action: Action to perform (add/update/remove).
716 * @value: Value to assign to the QoS request.
717 */
718static int freq_qos_apply(struct freq_qos_request *req,
719 enum pm_qos_req_action action, s32 value)
720{
721 int ret;
722
723 switch(req->type) {
724 case FREQ_QOS_MIN:
725 ret = pm_qos_update_target(&req->qos->min_freq, &req->pnode,
726 action, value);
727 break;
728 case FREQ_QOS_MAX:
729 ret = pm_qos_update_target(&req->qos->max_freq, &req->pnode,
730 action, value);
731 break;
732 default:
733 ret = -EINVAL;
734 }
735
736 return ret;
737}
738
739/**
740 * freq_qos_add_request - Insert new frequency QoS request into a given list.
741 * @qos: Constraints to update.
742 * @req: Preallocated request object.
743 * @type: Request type.
744 * @value: Request value.
745 *
746 * Insert a new entry into the @qos list of requests, recompute the effective
747 * QoS constraint value for that list and initialize the @req object. The
748 * caller needs to save that object for later use in updates and removal.
749 *
750 * Return 1 if the effective constraint value has changed, 0 if the effective
751 * constraint value has not changed, or a negative error code on failures.
752 */
753int freq_qos_add_request(struct freq_constraints *qos,
754 struct freq_qos_request *req,
755 enum freq_qos_req_type type, s32 value)
756{
757 int ret;
758
759 if (IS_ERR_OR_NULL(qos) || !req)
760 return -EINVAL;
761
762 if (WARN(freq_qos_request_active(req),
763 "%s() called for active request\n", __func__))
764 return -EINVAL;
765
766 req->qos = qos;
767 req->type = type;
768 ret = freq_qos_apply(req, PM_QOS_ADD_REQ, value);
769 if (ret < 0) {
770 req->qos = NULL;
771 req->type = 0;
772 }
773
774 return ret;
775}
776EXPORT_SYMBOL_GPL(freq_qos_add_request);
777
778/**
779 * freq_qos_update_request - Modify existing frequency QoS request.
780 * @req: Request to modify.
781 * @new_value: New request value.
782 *
783 * Update an existing frequency QoS request along with the effective constraint
784 * value for the list of requests it belongs to.
785 *
786 * Return 1 if the effective constraint value has changed, 0 if the effective
787 * constraint value has not changed, or a negative error code on failures.
788 */
789int freq_qos_update_request(struct freq_qos_request *req, s32 new_value)
790{
791 if (!req)
792 return -EINVAL;
793
794 if (WARN(!freq_qos_request_active(req),
795 "%s() called for unknown object\n", __func__))
796 return -EINVAL;
797
798 if (req->pnode.prio == new_value)
799 return 0;
800
801 return freq_qos_apply(req, PM_QOS_UPDATE_REQ, new_value);
802}
803EXPORT_SYMBOL_GPL(freq_qos_update_request);
804
805/**
806 * freq_qos_remove_request - Remove frequency QoS request from its list.
807 * @req: Request to remove.
808 *
809 * Remove the given frequency QoS request from the list of constraints it
810 * belongs to and recompute the effective constraint value for that list.
811 *
812 * Return 1 if the effective constraint value has changed, 0 if the effective
813 * constraint value has not changed, or a negative error code on failures.
814 */
815int freq_qos_remove_request(struct freq_qos_request *req)
816{
817 int ret;
818
819 if (!req)
820 return -EINVAL;
821
822 if (WARN(!freq_qos_request_active(req),
823 "%s() called for unknown object\n", __func__))
824 return -EINVAL;
825
826 ret = freq_qos_apply(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
827 req->qos = NULL;
828 req->type = 0;
829
830 return ret;
831}
832EXPORT_SYMBOL_GPL(freq_qos_remove_request);
833
834/**
835 * freq_qos_add_notifier - Add frequency QoS change notifier.
836 * @qos: List of requests to add the notifier to.
837 * @type: Request type.
838 * @notifier: Notifier block to add.
839 */
840int freq_qos_add_notifier(struct freq_constraints *qos,
841 enum freq_qos_req_type type,
842 struct notifier_block *notifier)
843{
844 int ret;
845
846 if (IS_ERR_OR_NULL(qos) || !notifier)
847 return -EINVAL;
848
849 switch (type) {
850 case FREQ_QOS_MIN:
851 ret = blocking_notifier_chain_register(qos->min_freq.notifiers,
852 notifier);
853 break;
854 case FREQ_QOS_MAX:
855 ret = blocking_notifier_chain_register(qos->max_freq.notifiers,
856 notifier);
857 break;
858 default:
859 WARN_ON(1);
860 ret = -EINVAL;
861 }
862
863 return ret;
864}
865EXPORT_SYMBOL_GPL(freq_qos_add_notifier);
866
867/**
868 * freq_qos_remove_notifier - Remove frequency QoS change notifier.
869 * @qos: List of requests to remove the notifier from.
870 * @type: Request type.
871 * @notifier: Notifier block to remove.
872 */
873int freq_qos_remove_notifier(struct freq_constraints *qos,
874 enum freq_qos_req_type type,
875 struct notifier_block *notifier)
876{
877 int ret;
878
879 if (IS_ERR_OR_NULL(qos) || !notifier)
880 return -EINVAL;
881
882 switch (type) {
883 case FREQ_QOS_MIN:
884 ret = blocking_notifier_chain_unregister(qos->min_freq.notifiers,
885 notifier);
886 break;
887 case FREQ_QOS_MAX:
888 ret = blocking_notifier_chain_unregister(qos->max_freq.notifiers,
889 notifier);
890 break;
891 default:
892 WARN_ON(1);
893 ret = -EINVAL;
894 }
895
896 return ret;
897}
898EXPORT_SYMBOL_GPL(freq_qos_remove_notifier);