projects/linux·blob v4.16 · refs

1029 lines · 25.5 KiB

1/*
2 * RTC subsystem, interface functions
3 *
4 * Copyright (C) 2005 Tower Technologies
5 * Author: Alessandro Zummo <[email protected]>
6 *
7 * based on arch/arm/common/rtctime.c
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12*/
13
14#include <linux/rtc.h>
15#include <linux/sched.h>
16#include <linux/module.h>
17#include <linux/log2.h>
18#include <linux/workqueue.h>
19
20static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer);
21static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer);
22
23static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
24{
25 int err;
26 if (!rtc->ops)
27 err = -ENODEV;
28 else if (!rtc->ops->read_time)
29 err = -EINVAL;
30 else {
31 memset(tm, 0, sizeof(struct rtc_time));
32 err = rtc->ops->read_time(rtc->dev.parent, tm);
33 if (err < 0) {
34 dev_dbg(&rtc->dev, "read_time: fail to read: %d\n",
35 err);
36 return err;
37 }
38
39 err = rtc_valid_tm(tm);
40 if (err < 0)
41 dev_dbg(&rtc->dev, "read_time: rtc_time isn't valid\n");
42 }
43 return err;
44}
45
46int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
47{
48 int err;
49
50 err = mutex_lock_interruptible(&rtc->ops_lock);
51 if (err)
52 return err;
53
54 err = __rtc_read_time(rtc, tm);
55 mutex_unlock(&rtc->ops_lock);
56 return err;
57}
58EXPORT_SYMBOL_GPL(rtc_read_time);
59
60int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
61{
62 int err;
63
64 err = rtc_valid_tm(tm);
65 if (err != 0)
66 return err;
67
68 err = mutex_lock_interruptible(&rtc->ops_lock);
69 if (err)
70 return err;
71
72 if (!rtc->ops)
73 err = -ENODEV;
74 else if (rtc->ops->set_time)
75 err = rtc->ops->set_time(rtc->dev.parent, tm);
76 else if (rtc->ops->set_mmss64) {
77 time64_t secs64 = rtc_tm_to_time64(tm);
78
79 err = rtc->ops->set_mmss64(rtc->dev.parent, secs64);
80 } else if (rtc->ops->set_mmss) {
81 time64_t secs64 = rtc_tm_to_time64(tm);
82 err = rtc->ops->set_mmss(rtc->dev.parent, secs64);
83 } else
84 err = -EINVAL;
85
86 pm_stay_awake(rtc->dev.parent);
87 mutex_unlock(&rtc->ops_lock);
88 /* A timer might have just expired */
89 schedule_work(&rtc->irqwork);
90 return err;
91}
92EXPORT_SYMBOL_GPL(rtc_set_time);
93
94static int rtc_read_alarm_internal(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
95{
96 int err;
97
98 err = mutex_lock_interruptible(&rtc->ops_lock);
99 if (err)
100 return err;
101
102 if (rtc->ops == NULL)
103 err = -ENODEV;
104 else if (!rtc->ops->read_alarm)
105 err = -EINVAL;
106 else {
107 alarm->enabled = 0;
108 alarm->pending = 0;
109 alarm->time.tm_sec = -1;
110 alarm->time.tm_min = -1;
111 alarm->time.tm_hour = -1;
112 alarm->time.tm_mday = -1;
113 alarm->time.tm_mon = -1;
114 alarm->time.tm_year = -1;
115 alarm->time.tm_wday = -1;
116 alarm->time.tm_yday = -1;
117 alarm->time.tm_isdst = -1;
118 err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
119 }
120
121 mutex_unlock(&rtc->ops_lock);
122 return err;
123}
124
125int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
126{
127 int err;
128 struct rtc_time before, now;
129 int first_time = 1;
130 time64_t t_now, t_alm;
131 enum { none, day, month, year } missing = none;
132 unsigned days;
133
134 /* The lower level RTC driver may return -1 in some fields,
135 * creating invalid alarm->time values, for reasons like:
136 *
137 * - The hardware may not be capable of filling them in;
138 * many alarms match only on time-of-day fields, not
139 * day/month/year calendar data.
140 *
141 * - Some hardware uses illegal values as "wildcard" match
142 * values, which non-Linux firmware (like a BIOS) may try
143 * to set up as e.g. "alarm 15 minutes after each hour".
144 * Linux uses only oneshot alarms.
145 *
146 * When we see that here, we deal with it by using values from
147 * a current RTC timestamp for any missing (-1) values. The
148 * RTC driver prevents "periodic alarm" modes.
149 *
150 * But this can be racey, because some fields of the RTC timestamp
151 * may have wrapped in the interval since we read the RTC alarm,
152 * which would lead to us inserting inconsistent values in place
153 * of the -1 fields.
154 *
155 * Reading the alarm and timestamp in the reverse sequence
156 * would have the same race condition, and not solve the issue.
157 *
158 * So, we must first read the RTC timestamp,
159 * then read the RTC alarm value,
160 * and then read a second RTC timestamp.
161 *
162 * If any fields of the second timestamp have changed
163 * when compared with the first timestamp, then we know
164 * our timestamp may be inconsistent with that used by
165 * the low-level rtc_read_alarm_internal() function.
166 *
167 * So, when the two timestamps disagree, we just loop and do
168 * the process again to get a fully consistent set of values.
169 *
170 * This could all instead be done in the lower level driver,
171 * but since more than one lower level RTC implementation needs it,
172 * then it's probably best best to do it here instead of there..
173 */
174
175 /* Get the "before" timestamp */
176 err = rtc_read_time(rtc, &before);
177 if (err < 0)
178 return err;
179 do {
180 if (!first_time)
181 memcpy(&before, &now, sizeof(struct rtc_time));
182 first_time = 0;
183
184 /* get the RTC alarm values, which may be incomplete */
185 err = rtc_read_alarm_internal(rtc, alarm);
186 if (err)
187 return err;
188
189 /* full-function RTCs won't have such missing fields */
190 if (rtc_valid_tm(&alarm->time) == 0)
191 return 0;
192
193 /* get the "after" timestamp, to detect wrapped fields */
194 err = rtc_read_time(rtc, &now);
195 if (err < 0)
196 return err;
197
198 /* note that tm_sec is a "don't care" value here: */
199 } while ( before.tm_min != now.tm_min
200 || before.tm_hour != now.tm_hour
201 || before.tm_mon != now.tm_mon
202 || before.tm_year != now.tm_year);
203
204 /* Fill in the missing alarm fields using the timestamp; we
205 * know there's at least one since alarm->time is invalid.
206 */
207 if (alarm->time.tm_sec == -1)
208 alarm->time.tm_sec = now.tm_sec;
209 if (alarm->time.tm_min == -1)
210 alarm->time.tm_min = now.tm_min;
211 if (alarm->time.tm_hour == -1)
212 alarm->time.tm_hour = now.tm_hour;
213
214 /* For simplicity, only support date rollover for now */
215 if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) {
216 alarm->time.tm_mday = now.tm_mday;
217 missing = day;
218 }
219 if ((unsigned)alarm->time.tm_mon >= 12) {
220 alarm->time.tm_mon = now.tm_mon;
221 if (missing == none)
222 missing = month;
223 }
224 if (alarm->time.tm_year == -1) {
225 alarm->time.tm_year = now.tm_year;
226 if (missing == none)
227 missing = year;
228 }
229
230 /* Can't proceed if alarm is still invalid after replacing
231 * missing fields.
232 */
233 err = rtc_valid_tm(&alarm->time);
234 if (err)
235 goto done;
236
237 /* with luck, no rollover is needed */
238 t_now = rtc_tm_to_time64(&now);
239 t_alm = rtc_tm_to_time64(&alarm->time);
240 if (t_now < t_alm)
241 goto done;
242
243 switch (missing) {
244
245 /* 24 hour rollover ... if it's now 10am Monday, an alarm that
246 * that will trigger at 5am will do so at 5am Tuesday, which
247 * could also be in the next month or year. This is a common
248 * case, especially for PCs.
249 */
250 case day:
251 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
252 t_alm += 24 * 60 * 60;
253 rtc_time64_to_tm(t_alm, &alarm->time);
254 break;
255
256 /* Month rollover ... if it's the 31th, an alarm on the 3rd will
257 * be next month. An alarm matching on the 30th, 29th, or 28th
258 * may end up in the month after that! Many newer PCs support
259 * this type of alarm.
260 */
261 case month:
262 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
263 do {
264 if (alarm->time.tm_mon < 11)
265 alarm->time.tm_mon++;
266 else {
267 alarm->time.tm_mon = 0;
268 alarm->time.tm_year++;
269 }
270 days = rtc_month_days(alarm->time.tm_mon,
271 alarm->time.tm_year);
272 } while (days < alarm->time.tm_mday);
273 break;
274
275 /* Year rollover ... easy except for leap years! */
276 case year:
277 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
278 do {
279 alarm->time.tm_year++;
280 } while (!is_leap_year(alarm->time.tm_year + 1900)
281 && rtc_valid_tm(&alarm->time) != 0);
282 break;
283
284 default:
285 dev_warn(&rtc->dev, "alarm rollover not handled\n");
286 }
287
288 err = rtc_valid_tm(&alarm->time);
289
290done:
291 if (err) {
292 dev_warn(&rtc->dev, "invalid alarm value: %d-%d-%d %d:%d:%d\n",
293 alarm->time.tm_year + 1900, alarm->time.tm_mon + 1,
294 alarm->time.tm_mday, alarm->time.tm_hour, alarm->time.tm_min,
295 alarm->time.tm_sec);
296 }
297
298 return err;
299}
300
301int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
302{
303 int err;
304
305 err = mutex_lock_interruptible(&rtc->ops_lock);
306 if (err)
307 return err;
308 if (rtc->ops == NULL)
309 err = -ENODEV;
310 else if (!rtc->ops->read_alarm)
311 err = -EINVAL;
312 else {
313 memset(alarm, 0, sizeof(struct rtc_wkalrm));
314 alarm->enabled = rtc->aie_timer.enabled;
315 alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
316 }
317 mutex_unlock(&rtc->ops_lock);
318
319 return err;
320}
321EXPORT_SYMBOL_GPL(rtc_read_alarm);
322
323static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
324{
325 struct rtc_time tm;
326 time64_t now, scheduled;
327 int err;
328
329 err = rtc_valid_tm(&alarm->time);
330 if (err)
331 return err;
332 scheduled = rtc_tm_to_time64(&alarm->time);
333
334 /* Make sure we're not setting alarms in the past */
335 err = __rtc_read_time(rtc, &tm);
336 if (err)
337 return err;
338 now = rtc_tm_to_time64(&tm);
339 if (scheduled <= now)
340 return -ETIME;
341 /*
342 * XXX - We just checked to make sure the alarm time is not
343 * in the past, but there is still a race window where if
344 * the is alarm set for the next second and the second ticks
345 * over right here, before we set the alarm.
346 */
347
348 if (!rtc->ops)
349 err = -ENODEV;
350 else if (!rtc->ops->set_alarm)
351 err = -EINVAL;
352 else
353 err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
354
355 return err;
356}
357
358int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
359{
360 int err;
361
362 err = rtc_valid_tm(&alarm->time);
363 if (err != 0)
364 return err;
365
366 err = mutex_lock_interruptible(&rtc->ops_lock);
367 if (err)
368 return err;
369 if (rtc->aie_timer.enabled)
370 rtc_timer_remove(rtc, &rtc->aie_timer);
371
372 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
373 rtc->aie_timer.period = 0;
374 if (alarm->enabled)
375 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
376
377 mutex_unlock(&rtc->ops_lock);
378 return err;
379}
380EXPORT_SYMBOL_GPL(rtc_set_alarm);
381
382/* Called once per device from rtc_device_register */
383int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
384{
385 int err;
386 struct rtc_time now;
387
388 err = rtc_valid_tm(&alarm->time);
389 if (err != 0)
390 return err;
391
392 err = rtc_read_time(rtc, &now);
393 if (err)
394 return err;
395
396 err = mutex_lock_interruptible(&rtc->ops_lock);
397 if (err)
398 return err;
399
400 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
401 rtc->aie_timer.period = 0;
402
403 /* Alarm has to be enabled & in the future for us to enqueue it */
404 if (alarm->enabled && (rtc_tm_to_ktime(now) <
405 rtc->aie_timer.node.expires)) {
406
407 rtc->aie_timer.enabled = 1;
408 timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
409 }
410 mutex_unlock(&rtc->ops_lock);
411 return err;
412}
413EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
414
415int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
416{
417 int err = mutex_lock_interruptible(&rtc->ops_lock);
418 if (err)
419 return err;
420
421 if (rtc->aie_timer.enabled != enabled) {
422 if (enabled)
423 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
424 else
425 rtc_timer_remove(rtc, &rtc->aie_timer);
426 }
427
428 if (err)
429 /* nothing */;
430 else if (!rtc->ops)
431 err = -ENODEV;
432 else if (!rtc->ops->alarm_irq_enable)
433 err = -EINVAL;
434 else
435 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
436
437 mutex_unlock(&rtc->ops_lock);
438 return err;
439}
440EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
441
442int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
443{
444 int err = mutex_lock_interruptible(&rtc->ops_lock);
445 if (err)
446 return err;
447
448#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
449 if (enabled == 0 && rtc->uie_irq_active) {
450 mutex_unlock(&rtc->ops_lock);
451 return rtc_dev_update_irq_enable_emul(rtc, 0);
452 }
453#endif
454 /* make sure we're changing state */
455 if (rtc->uie_rtctimer.enabled == enabled)
456 goto out;
457
458 if (rtc->uie_unsupported) {
459 err = -EINVAL;
460 goto out;
461 }
462
463 if (enabled) {
464 struct rtc_time tm;
465 ktime_t now, onesec;
466
467 __rtc_read_time(rtc, &tm);
468 onesec = ktime_set(1, 0);
469 now = rtc_tm_to_ktime(tm);
470 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
471 rtc->uie_rtctimer.period = ktime_set(1, 0);
472 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
473 } else
474 rtc_timer_remove(rtc, &rtc->uie_rtctimer);
475
476out:
477 mutex_unlock(&rtc->ops_lock);
478#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
479 /*
480 * Enable emulation if the driver did not provide
481 * the update_irq_enable function pointer or if returned
482 * -EINVAL to signal that it has been configured without
483 * interrupts or that are not available at the moment.
484 */
485 if (err == -EINVAL)
486 err = rtc_dev_update_irq_enable_emul(rtc, enabled);
487#endif
488 return err;
489
490}
491EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
492
493
494/**
495 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
496 * @rtc: pointer to the rtc device
497 *
498 * This function is called when an AIE, UIE or PIE mode interrupt
499 * has occurred (or been emulated).
500 *
501 * Triggers the registered irq_task function callback.
502 */
503void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
504{
505 unsigned long flags;
506
507 /* mark one irq of the appropriate mode */
508 spin_lock_irqsave(&rtc->irq_lock, flags);
509 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF|mode);
510 spin_unlock_irqrestore(&rtc->irq_lock, flags);
511
512 /* call the task func */
513 spin_lock_irqsave(&rtc->irq_task_lock, flags);
514 if (rtc->irq_task)
515 rtc->irq_task->func(rtc->irq_task->private_data);
516 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
517
518 wake_up_interruptible(&rtc->irq_queue);
519 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
520}
521
522
523/**
524 * rtc_aie_update_irq - AIE mode rtctimer hook
525 * @private: pointer to the rtc_device
526 *
527 * This functions is called when the aie_timer expires.
528 */
529void rtc_aie_update_irq(void *private)
530{
531 struct rtc_device *rtc = (struct rtc_device *)private;
532 rtc_handle_legacy_irq(rtc, 1, RTC_AF);
533}
534
535
536/**
537 * rtc_uie_update_irq - UIE mode rtctimer hook
538 * @private: pointer to the rtc_device
539 *
540 * This functions is called when the uie_timer expires.
541 */
542void rtc_uie_update_irq(void *private)
543{
544 struct rtc_device *rtc = (struct rtc_device *)private;
545 rtc_handle_legacy_irq(rtc, 1, RTC_UF);
546}
547
548
549/**
550 * rtc_pie_update_irq - PIE mode hrtimer hook
551 * @timer: pointer to the pie mode hrtimer
552 *
553 * This function is used to emulate PIE mode interrupts
554 * using an hrtimer. This function is called when the periodic
555 * hrtimer expires.
556 */
557enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
558{
559 struct rtc_device *rtc;
560 ktime_t period;
561 int count;
562 rtc = container_of(timer, struct rtc_device, pie_timer);
563
564 period = NSEC_PER_SEC / rtc->irq_freq;
565 count = hrtimer_forward_now(timer, period);
566
567 rtc_handle_legacy_irq(rtc, count, RTC_PF);
568
569 return HRTIMER_RESTART;
570}
571
572/**
573 * rtc_update_irq - Triggered when a RTC interrupt occurs.
574 * @rtc: the rtc device
575 * @num: how many irqs are being reported (usually one)
576 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
577 * Context: any
578 */
579void rtc_update_irq(struct rtc_device *rtc,
580 unsigned long num, unsigned long events)
581{
582 if (IS_ERR_OR_NULL(rtc))
583 return;
584
585 pm_stay_awake(rtc->dev.parent);
586 schedule_work(&rtc->irqwork);
587}
588EXPORT_SYMBOL_GPL(rtc_update_irq);
589
590static int __rtc_match(struct device *dev, const void *data)
591{
592 const char *name = data;
593
594 if (strcmp(dev_name(dev), name) == 0)
595 return 1;
596 return 0;
597}
598
599struct rtc_device *rtc_class_open(const char *name)
600{
601 struct device *dev;
602 struct rtc_device *rtc = NULL;
603
604 dev = class_find_device(rtc_class, NULL, name, __rtc_match);
605 if (dev)
606 rtc = to_rtc_device(dev);
607
608 if (rtc) {
609 if (!try_module_get(rtc->owner)) {
610 put_device(dev);
611 rtc = NULL;
612 }
613 }
614
615 return rtc;
616}
617EXPORT_SYMBOL_GPL(rtc_class_open);
618
619void rtc_class_close(struct rtc_device *rtc)
620{
621 module_put(rtc->owner);
622 put_device(&rtc->dev);
623}
624EXPORT_SYMBOL_GPL(rtc_class_close);
625
626int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
627{
628 int retval = -EBUSY;
629
630 if (task == NULL || task->func == NULL)
631 return -EINVAL;
632
633 /* Cannot register while the char dev is in use */
634 if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
635 return -EBUSY;
636
637 spin_lock_irq(&rtc->irq_task_lock);
638 if (rtc->irq_task == NULL) {
639 rtc->irq_task = task;
640 retval = 0;
641 }
642 spin_unlock_irq(&rtc->irq_task_lock);
643
644 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
645
646 return retval;
647}
648EXPORT_SYMBOL_GPL(rtc_irq_register);
649
650void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task)
651{
652 spin_lock_irq(&rtc->irq_task_lock);
653 if (rtc->irq_task == task)
654 rtc->irq_task = NULL;
655 spin_unlock_irq(&rtc->irq_task_lock);
656}
657EXPORT_SYMBOL_GPL(rtc_irq_unregister);
658
659static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
660{
661 /*
662 * We always cancel the timer here first, because otherwise
663 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
664 * when we manage to start the timer before the callback
665 * returns HRTIMER_RESTART.
666 *
667 * We cannot use hrtimer_cancel() here as a running callback
668 * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
669 * would spin forever.
670 */
671 if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
672 return -1;
673
674 if (enabled) {
675 ktime_t period = NSEC_PER_SEC / rtc->irq_freq;
676
677 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
678 }
679 return 0;
680}
681
682/**
683 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
684 * @rtc: the rtc device
685 * @task: currently registered with rtc_irq_register()
686 * @enabled: true to enable periodic IRQs
687 * Context: any
688 *
689 * Note that rtc_irq_set_freq() should previously have been used to
690 * specify the desired frequency of periodic IRQ task->func() callbacks.
691 */
692int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled)
693{
694 int err = 0;
695 unsigned long flags;
696
697retry:
698 spin_lock_irqsave(&rtc->irq_task_lock, flags);
699 if (rtc->irq_task != NULL && task == NULL)
700 err = -EBUSY;
701 else if (rtc->irq_task != task)
702 err = -EACCES;
703 else {
704 if (rtc_update_hrtimer(rtc, enabled) < 0) {
705 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
706 cpu_relax();
707 goto retry;
708 }
709 rtc->pie_enabled = enabled;
710 }
711 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
712 return err;
713}
714EXPORT_SYMBOL_GPL(rtc_irq_set_state);
715
716/**
717 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
718 * @rtc: the rtc device
719 * @task: currently registered with rtc_irq_register()
720 * @freq: positive frequency with which task->func() will be called
721 * Context: any
722 *
723 * Note that rtc_irq_set_state() is used to enable or disable the
724 * periodic IRQs.
725 */
726int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
727{
728 int err = 0;
729 unsigned long flags;
730
731 if (freq <= 0 || freq > RTC_MAX_FREQ)
732 return -EINVAL;
733retry:
734 spin_lock_irqsave(&rtc->irq_task_lock, flags);
735 if (rtc->irq_task != NULL && task == NULL)
736 err = -EBUSY;
737 else if (rtc->irq_task != task)
738 err = -EACCES;
739 else {
740 rtc->irq_freq = freq;
741 if (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0) {
742 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
743 cpu_relax();
744 goto retry;
745 }
746 }
747 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
748 return err;
749}
750EXPORT_SYMBOL_GPL(rtc_irq_set_freq);
751
752/**
753 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
754 * @rtc rtc device
755 * @timer timer being added.
756 *
757 * Enqueues a timer onto the rtc devices timerqueue and sets
758 * the next alarm event appropriately.
759 *
760 * Sets the enabled bit on the added timer.
761 *
762 * Must hold ops_lock for proper serialization of timerqueue
763 */
764static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
765{
766 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
767 struct rtc_time tm;
768 ktime_t now;
769
770 timer->enabled = 1;
771 __rtc_read_time(rtc, &tm);
772 now = rtc_tm_to_ktime(tm);
773
774 /* Skip over expired timers */
775 while (next) {
776 if (next->expires >= now)
777 break;
778 next = timerqueue_iterate_next(next);
779 }
780
781 timerqueue_add(&rtc->timerqueue, &timer->node);
782 if (!next || ktime_before(timer->node.expires, next->expires)) {
783 struct rtc_wkalrm alarm;
784 int err;
785 alarm.time = rtc_ktime_to_tm(timer->node.expires);
786 alarm.enabled = 1;
787 err = __rtc_set_alarm(rtc, &alarm);
788 if (err == -ETIME) {
789 pm_stay_awake(rtc->dev.parent);
790 schedule_work(&rtc->irqwork);
791 } else if (err) {
792 timerqueue_del(&rtc->timerqueue, &timer->node);
793 timer->enabled = 0;
794 return err;
795 }
796 }
797 return 0;
798}
799
800static void rtc_alarm_disable(struct rtc_device *rtc)
801{
802 if (!rtc->ops || !rtc->ops->alarm_irq_enable)
803 return;
804
805 rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
806}
807
808/**
809 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
810 * @rtc rtc device
811 * @timer timer being removed.
812 *
813 * Removes a timer onto the rtc devices timerqueue and sets
814 * the next alarm event appropriately.
815 *
816 * Clears the enabled bit on the removed timer.
817 *
818 * Must hold ops_lock for proper serialization of timerqueue
819 */
820static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
821{
822 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
823 timerqueue_del(&rtc->timerqueue, &timer->node);
824 timer->enabled = 0;
825 if (next == &timer->node) {
826 struct rtc_wkalrm alarm;
827 int err;
828 next = timerqueue_getnext(&rtc->timerqueue);
829 if (!next) {
830 rtc_alarm_disable(rtc);
831 return;
832 }
833 alarm.time = rtc_ktime_to_tm(next->expires);
834 alarm.enabled = 1;
835 err = __rtc_set_alarm(rtc, &alarm);
836 if (err == -ETIME) {
837 pm_stay_awake(rtc->dev.parent);
838 schedule_work(&rtc->irqwork);
839 }
840 }
841}
842
843/**
844 * rtc_timer_do_work - Expires rtc timers
845 * @rtc rtc device
846 * @timer timer being removed.
847 *
848 * Expires rtc timers. Reprograms next alarm event if needed.
849 * Called via worktask.
850 *
851 * Serializes access to timerqueue via ops_lock mutex
852 */
853void rtc_timer_do_work(struct work_struct *work)
854{
855 struct rtc_timer *timer;
856 struct timerqueue_node *next;
857 ktime_t now;
858 struct rtc_time tm;
859
860 struct rtc_device *rtc =
861 container_of(work, struct rtc_device, irqwork);
862
863 mutex_lock(&rtc->ops_lock);
864again:
865 __rtc_read_time(rtc, &tm);
866 now = rtc_tm_to_ktime(tm);
867 while ((next = timerqueue_getnext(&rtc->timerqueue))) {
868 if (next->expires > now)
869 break;
870
871 /* expire timer */
872 timer = container_of(next, struct rtc_timer, node);
873 timerqueue_del(&rtc->timerqueue, &timer->node);
874 timer->enabled = 0;
875 if (timer->task.func)
876 timer->task.func(timer->task.private_data);
877
878 /* Re-add/fwd periodic timers */
879 if (ktime_to_ns(timer->period)) {
880 timer->node.expires = ktime_add(timer->node.expires,
881 timer->period);
882 timer->enabled = 1;
883 timerqueue_add(&rtc->timerqueue, &timer->node);
884 }
885 }
886
887 /* Set next alarm */
888 if (next) {
889 struct rtc_wkalrm alarm;
890 int err;
891 int retry = 3;
892
893 alarm.time = rtc_ktime_to_tm(next->expires);
894 alarm.enabled = 1;
895reprogram:
896 err = __rtc_set_alarm(rtc, &alarm);
897 if (err == -ETIME)
898 goto again;
899 else if (err) {
900 if (retry-- > 0)
901 goto reprogram;
902
903 timer = container_of(next, struct rtc_timer, node);
904 timerqueue_del(&rtc->timerqueue, &timer->node);
905 timer->enabled = 0;
906 dev_err(&rtc->dev, "__rtc_set_alarm: err=%d\n", err);
907 goto again;
908 }
909 } else
910 rtc_alarm_disable(rtc);
911
912 pm_relax(rtc->dev.parent);
913 mutex_unlock(&rtc->ops_lock);
914}
915
916
917/* rtc_timer_init - Initializes an rtc_timer
918 * @timer: timer to be intiialized
919 * @f: function pointer to be called when timer fires
920 * @data: private data passed to function pointer
921 *
922 * Kernel interface to initializing an rtc_timer.
923 */
924void rtc_timer_init(struct rtc_timer *timer, void (*f)(void *p), void *data)
925{
926 timerqueue_init(&timer->node);
927 timer->enabled = 0;
928 timer->task.func = f;
929 timer->task.private_data = data;
930}
931
932/* rtc_timer_start - Sets an rtc_timer to fire in the future
933 * @ rtc: rtc device to be used
934 * @ timer: timer being set
935 * @ expires: time at which to expire the timer
936 * @ period: period that the timer will recur
937 *
938 * Kernel interface to set an rtc_timer
939 */
940int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
941 ktime_t expires, ktime_t period)
942{
943 int ret = 0;
944 mutex_lock(&rtc->ops_lock);
945 if (timer->enabled)
946 rtc_timer_remove(rtc, timer);
947
948 timer->node.expires = expires;
949 timer->period = period;
950
951 ret = rtc_timer_enqueue(rtc, timer);
952
953 mutex_unlock(&rtc->ops_lock);
954 return ret;
955}
956
957/* rtc_timer_cancel - Stops an rtc_timer
958 * @ rtc: rtc device to be used
959 * @ timer: timer being set
960 *
961 * Kernel interface to cancel an rtc_timer
962 */
963void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
964{
965 mutex_lock(&rtc->ops_lock);
966 if (timer->enabled)
967 rtc_timer_remove(rtc, timer);
968 mutex_unlock(&rtc->ops_lock);
969}
970
971/**
972 * rtc_read_offset - Read the amount of rtc offset in parts per billion
973 * @ rtc: rtc device to be used
974 * @ offset: the offset in parts per billion
975 *
976 * see below for details.
977 *
978 * Kernel interface to read rtc clock offset
979 * Returns 0 on success, or a negative number on error.
980 * If read_offset() is not implemented for the rtc, return -EINVAL
981 */
982int rtc_read_offset(struct rtc_device *rtc, long *offset)
983{
984 int ret;
985
986 if (!rtc->ops)
987 return -ENODEV;
988
989 if (!rtc->ops->read_offset)
990 return -EINVAL;
991
992 mutex_lock(&rtc->ops_lock);
993 ret = rtc->ops->read_offset(rtc->dev.parent, offset);
994 mutex_unlock(&rtc->ops_lock);
995 return ret;
996}
997
998/**
999 * rtc_set_offset - Adjusts the duration of the average second
1000 * @ rtc: rtc device to be used
1001 * @ offset: the offset in parts per billion
1002 *
1003 * Some rtc's allow an adjustment to the average duration of a second
1004 * to compensate for differences in the actual clock rate due to temperature,
1005 * the crystal, capacitor, etc.
1006 *
1007 * The adjustment applied is as follows:
1008 * t = t0 * (1 + offset * 1e-9)
1009 * where t0 is the measured length of 1 RTC second with offset = 0
1010 *
1011 * Kernel interface to adjust an rtc clock offset.
1012 * Return 0 on success, or a negative number on error.
1013 * If the rtc offset is not setable (or not implemented), return -EINVAL
1014 */
1015int rtc_set_offset(struct rtc_device *rtc, long offset)
1016{
1017 int ret;
1018
1019 if (!rtc->ops)
1020 return -ENODEV;
1021
1022 if (!rtc->ops->set_offset)
1023 return -EINVAL;
1024
1025 mutex_lock(&rtc->ops_lock);
1026 ret = rtc->ops->set_offset(rtc->dev.parent, offset);
1027 mutex_unlock(&rtc->ops_lock);
1028 return ret;
1029}