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);