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1/*
2 * RTC subsystem, interface functions
3 *
4 * Copyright (C) 2005 Tower Technologies
5 * Author: Alessandro Zummo <a.zummo@towertech.it>
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/log2.h>
17#include <linux/workqueue.h>
18
19static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer);
20static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer);
21
22static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
23{
24 int err;
25 if (!rtc->ops)
26 err = -ENODEV;
27 else if (!rtc->ops->read_time)
28 err = -EINVAL;
29 else {
30 memset(tm, 0, sizeof(struct rtc_time));
31 err = rtc->ops->read_time(rtc->dev.parent, tm);
32 }
33 return err;
34}
35
36int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
37{
38 int err;
39
40 err = mutex_lock_interruptible(&rtc->ops_lock);
41 if (err)
42 return err;
43
44 err = __rtc_read_time(rtc, tm);
45 mutex_unlock(&rtc->ops_lock);
46 return err;
47}
48EXPORT_SYMBOL_GPL(rtc_read_time);
49
50int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
51{
52 int err;
53
54 err = rtc_valid_tm(tm);
55 if (err != 0)
56 return err;
57
58 err = mutex_lock_interruptible(&rtc->ops_lock);
59 if (err)
60 return err;
61
62 if (!rtc->ops)
63 err = -ENODEV;
64 else if (rtc->ops->set_time)
65 err = rtc->ops->set_time(rtc->dev.parent, tm);
66 else if (rtc->ops->set_mmss) {
67 unsigned long secs;
68 err = rtc_tm_to_time(tm, &secs);
69 if (err == 0)
70 err = rtc->ops->set_mmss(rtc->dev.parent, secs);
71 } else
72 err = -EINVAL;
73
74 mutex_unlock(&rtc->ops_lock);
75 return err;
76}
77EXPORT_SYMBOL_GPL(rtc_set_time);
78
79int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs)
80{
81 int err;
82
83 err = mutex_lock_interruptible(&rtc->ops_lock);
84 if (err)
85 return err;
86
87 if (!rtc->ops)
88 err = -ENODEV;
89 else if (rtc->ops->set_mmss)
90 err = rtc->ops->set_mmss(rtc->dev.parent, secs);
91 else if (rtc->ops->read_time && rtc->ops->set_time) {
92 struct rtc_time new, old;
93
94 err = rtc->ops->read_time(rtc->dev.parent, &old);
95 if (err == 0) {
96 rtc_time_to_tm(secs, &new);
97
98 /*
99 * avoid writing when we're going to change the day of
100 * the month. We will retry in the next minute. This
101 * basically means that if the RTC must not drift
102 * by more than 1 minute in 11 minutes.
103 */
104 if (!((old.tm_hour == 23 && old.tm_min == 59) ||
105 (new.tm_hour == 23 && new.tm_min == 59)))
106 err = rtc->ops->set_time(rtc->dev.parent,
107 &new);
108 }
109 }
110 else
111 err = -EINVAL;
112
113 mutex_unlock(&rtc->ops_lock);
114
115 return err;
116}
117EXPORT_SYMBOL_GPL(rtc_set_mmss);
118
119static int rtc_read_alarm_internal(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
120{
121 int err;
122
123 err = mutex_lock_interruptible(&rtc->ops_lock);
124 if (err)
125 return err;
126
127 if (rtc->ops == NULL)
128 err = -ENODEV;
129 else if (!rtc->ops->read_alarm)
130 err = -EINVAL;
131 else {
132 memset(alarm, 0, sizeof(struct rtc_wkalrm));
133 err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
134 }
135
136 mutex_unlock(&rtc->ops_lock);
137 return err;
138}
139
140int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
141{
142 int err;
143 struct rtc_time before, now;
144 int first_time = 1;
145 unsigned long t_now, t_alm;
146 enum { none, day, month, year } missing = none;
147 unsigned days;
148
149 /* The lower level RTC driver may return -1 in some fields,
150 * creating invalid alarm->time values, for reasons like:
151 *
152 * - The hardware may not be capable of filling them in;
153 * many alarms match only on time-of-day fields, not
154 * day/month/year calendar data.
155 *
156 * - Some hardware uses illegal values as "wildcard" match
157 * values, which non-Linux firmware (like a BIOS) may try
158 * to set up as e.g. "alarm 15 minutes after each hour".
159 * Linux uses only oneshot alarms.
160 *
161 * When we see that here, we deal with it by using values from
162 * a current RTC timestamp for any missing (-1) values. The
163 * RTC driver prevents "periodic alarm" modes.
164 *
165 * But this can be racey, because some fields of the RTC timestamp
166 * may have wrapped in the interval since we read the RTC alarm,
167 * which would lead to us inserting inconsistent values in place
168 * of the -1 fields.
169 *
170 * Reading the alarm and timestamp in the reverse sequence
171 * would have the same race condition, and not solve the issue.
172 *
173 * So, we must first read the RTC timestamp,
174 * then read the RTC alarm value,
175 * and then read a second RTC timestamp.
176 *
177 * If any fields of the second timestamp have changed
178 * when compared with the first timestamp, then we know
179 * our timestamp may be inconsistent with that used by
180 * the low-level rtc_read_alarm_internal() function.
181 *
182 * So, when the two timestamps disagree, we just loop and do
183 * the process again to get a fully consistent set of values.
184 *
185 * This could all instead be done in the lower level driver,
186 * but since more than one lower level RTC implementation needs it,
187 * then it's probably best best to do it here instead of there..
188 */
189
190 /* Get the "before" timestamp */
191 err = rtc_read_time(rtc, &before);
192 if (err < 0)
193 return err;
194 do {
195 if (!first_time)
196 memcpy(&before, &now, sizeof(struct rtc_time));
197 first_time = 0;
198
199 /* get the RTC alarm values, which may be incomplete */
200 err = rtc_read_alarm_internal(rtc, alarm);
201 if (err)
202 return err;
203
204 /* full-function RTCs won't have such missing fields */
205 if (rtc_valid_tm(&alarm->time) == 0)
206 return 0;
207
208 /* get the "after" timestamp, to detect wrapped fields */
209 err = rtc_read_time(rtc, &now);
210 if (err < 0)
211 return err;
212
213 /* note that tm_sec is a "don't care" value here: */
214 } while ( before.tm_min != now.tm_min
215 || before.tm_hour != now.tm_hour
216 || before.tm_mon != now.tm_mon
217 || before.tm_year != now.tm_year);
218
219 /* Fill in the missing alarm fields using the timestamp; we
220 * know there's at least one since alarm->time is invalid.
221 */
222 if (alarm->time.tm_sec == -1)
223 alarm->time.tm_sec = now.tm_sec;
224 if (alarm->time.tm_min == -1)
225 alarm->time.tm_min = now.tm_min;
226 if (alarm->time.tm_hour == -1)
227 alarm->time.tm_hour = now.tm_hour;
228
229 /* For simplicity, only support date rollover for now */
230 if (alarm->time.tm_mday == -1) {
231 alarm->time.tm_mday = now.tm_mday;
232 missing = day;
233 }
234 if (alarm->time.tm_mon == -1) {
235 alarm->time.tm_mon = now.tm_mon;
236 if (missing == none)
237 missing = month;
238 }
239 if (alarm->time.tm_year == -1) {
240 alarm->time.tm_year = now.tm_year;
241 if (missing == none)
242 missing = year;
243 }
244
245 /* with luck, no rollover is needed */
246 rtc_tm_to_time(&now, &t_now);
247 rtc_tm_to_time(&alarm->time, &t_alm);
248 if (t_now < t_alm)
249 goto done;
250
251 switch (missing) {
252
253 /* 24 hour rollover ... if it's now 10am Monday, an alarm that
254 * that will trigger at 5am will do so at 5am Tuesday, which
255 * could also be in the next month or year. This is a common
256 * case, especially for PCs.
257 */
258 case day:
259 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
260 t_alm += 24 * 60 * 60;
261 rtc_time_to_tm(t_alm, &alarm->time);
262 break;
263
264 /* Month rollover ... if it's the 31th, an alarm on the 3rd will
265 * be next month. An alarm matching on the 30th, 29th, or 28th
266 * may end up in the month after that! Many newer PCs support
267 * this type of alarm.
268 */
269 case month:
270 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
271 do {
272 if (alarm->time.tm_mon < 11)
273 alarm->time.tm_mon++;
274 else {
275 alarm->time.tm_mon = 0;
276 alarm->time.tm_year++;
277 }
278 days = rtc_month_days(alarm->time.tm_mon,
279 alarm->time.tm_year);
280 } while (days < alarm->time.tm_mday);
281 break;
282
283 /* Year rollover ... easy except for leap years! */
284 case year:
285 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
286 do {
287 alarm->time.tm_year++;
288 } while (rtc_valid_tm(&alarm->time) != 0);
289 break;
290
291 default:
292 dev_warn(&rtc->dev, "alarm rollover not handled\n");
293 }
294
295done:
296 return 0;
297}
298
299int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
300{
301 int err;
302
303 err = mutex_lock_interruptible(&rtc->ops_lock);
304 if (err)
305 return err;
306 if (rtc->ops == NULL)
307 err = -ENODEV;
308 else if (!rtc->ops->read_alarm)
309 err = -EINVAL;
310 else {
311 memset(alarm, 0, sizeof(struct rtc_wkalrm));
312 alarm->enabled = rtc->aie_timer.enabled;
313 alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
314 }
315 mutex_unlock(&rtc->ops_lock);
316
317 return err;
318}
319EXPORT_SYMBOL_GPL(rtc_read_alarm);
320
321static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
322{
323 struct rtc_time tm;
324 long now, scheduled;
325 int err;
326
327 err = rtc_valid_tm(&alarm->time);
328 if (err)
329 return err;
330 rtc_tm_to_time(&alarm->time, &scheduled);
331
332 /* Make sure we're not setting alarms in the past */
333 err = __rtc_read_time(rtc, &tm);
334 rtc_tm_to_time(&tm, &now);
335 if (scheduled <= now)
336 return -ETIME;
337 /*
338 * XXX - We just checked to make sure the alarm time is not
339 * in the past, but there is still a race window where if
340 * the is alarm set for the next second and the second ticks
341 * over right here, before we set the alarm.
342 */
343
344 if (!rtc->ops)
345 err = -ENODEV;
346 else if (!rtc->ops->set_alarm)
347 err = -EINVAL;
348 else
349 err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
350
351 return err;
352}
353
354int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
355{
356 int err;
357
358 err = rtc_valid_tm(&alarm->time);
359 if (err != 0)
360 return err;
361
362 err = mutex_lock_interruptible(&rtc->ops_lock);
363 if (err)
364 return err;
365 if (rtc->aie_timer.enabled) {
366 rtc_timer_remove(rtc, &rtc->aie_timer);
367 }
368 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
369 rtc->aie_timer.period = ktime_set(0, 0);
370 if (alarm->enabled) {
371 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
372 }
373 mutex_unlock(&rtc->ops_lock);
374 return err;
375}
376EXPORT_SYMBOL_GPL(rtc_set_alarm);
377
378/* Called once per device from rtc_device_register */
379int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
380{
381 int err;
382
383 err = rtc_valid_tm(&alarm->time);
384 if (err != 0)
385 return err;
386
387 err = mutex_lock_interruptible(&rtc->ops_lock);
388 if (err)
389 return err;
390
391 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
392 rtc->aie_timer.period = ktime_set(0, 0);
393 if (alarm->enabled) {
394 rtc->aie_timer.enabled = 1;
395 timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
396 }
397 mutex_unlock(&rtc->ops_lock);
398 return err;
399}
400EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
401
402
403
404int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
405{
406 int err = mutex_lock_interruptible(&rtc->ops_lock);
407 if (err)
408 return err;
409
410 if (rtc->aie_timer.enabled != enabled) {
411 if (enabled)
412 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
413 else
414 rtc_timer_remove(rtc, &rtc->aie_timer);
415 }
416
417 if (err)
418 /* nothing */;
419 else if (!rtc->ops)
420 err = -ENODEV;
421 else if (!rtc->ops->alarm_irq_enable)
422 err = -EINVAL;
423 else
424 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
425
426 mutex_unlock(&rtc->ops_lock);
427 return err;
428}
429EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
430
431int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
432{
433 int err = mutex_lock_interruptible(&rtc->ops_lock);
434 if (err)
435 return err;
436
437#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
438 if (enabled == 0 && rtc->uie_irq_active) {
439 mutex_unlock(&rtc->ops_lock);
440 return rtc_dev_update_irq_enable_emul(rtc, 0);
441 }
442#endif
443 /* make sure we're changing state */
444 if (rtc->uie_rtctimer.enabled == enabled)
445 goto out;
446
447 if (enabled) {
448 struct rtc_time tm;
449 ktime_t now, onesec;
450
451 __rtc_read_time(rtc, &tm);
452 onesec = ktime_set(1, 0);
453 now = rtc_tm_to_ktime(tm);
454 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
455 rtc->uie_rtctimer.period = ktime_set(1, 0);
456 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
457 } else
458 rtc_timer_remove(rtc, &rtc->uie_rtctimer);
459
460out:
461 mutex_unlock(&rtc->ops_lock);
462#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
463 /*
464 * Enable emulation if the driver did not provide
465 * the update_irq_enable function pointer or if returned
466 * -EINVAL to signal that it has been configured without
467 * interrupts or that are not available at the moment.
468 */
469 if (err == -EINVAL)
470 err = rtc_dev_update_irq_enable_emul(rtc, enabled);
471#endif
472 return err;
473
474}
475EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
476
477
478/**
479 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
480 * @rtc: pointer to the rtc device
481 *
482 * This function is called when an AIE, UIE or PIE mode interrupt
483 * has occurred (or been emulated).
484 *
485 * Triggers the registered irq_task function callback.
486 */
487void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
488{
489 unsigned long flags;
490
491 /* mark one irq of the appropriate mode */
492 spin_lock_irqsave(&rtc->irq_lock, flags);
493 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF|mode);
494 spin_unlock_irqrestore(&rtc->irq_lock, flags);
495
496 /* call the task func */
497 spin_lock_irqsave(&rtc->irq_task_lock, flags);
498 if (rtc->irq_task)
499 rtc->irq_task->func(rtc->irq_task->private_data);
500 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
501
502 wake_up_interruptible(&rtc->irq_queue);
503 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
504}
505
506
507/**
508 * rtc_aie_update_irq - AIE mode rtctimer hook
509 * @private: pointer to the rtc_device
510 *
511 * This functions is called when the aie_timer expires.
512 */
513void rtc_aie_update_irq(void *private)
514{
515 struct rtc_device *rtc = (struct rtc_device *)private;
516 rtc_handle_legacy_irq(rtc, 1, RTC_AF);
517}
518
519
520/**
521 * rtc_uie_update_irq - UIE mode rtctimer hook
522 * @private: pointer to the rtc_device
523 *
524 * This functions is called when the uie_timer expires.
525 */
526void rtc_uie_update_irq(void *private)
527{
528 struct rtc_device *rtc = (struct rtc_device *)private;
529 rtc_handle_legacy_irq(rtc, 1, RTC_UF);
530}
531
532
533/**
534 * rtc_pie_update_irq - PIE mode hrtimer hook
535 * @timer: pointer to the pie mode hrtimer
536 *
537 * This function is used to emulate PIE mode interrupts
538 * using an hrtimer. This function is called when the periodic
539 * hrtimer expires.
540 */
541enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
542{
543 struct rtc_device *rtc;
544 ktime_t period;
545 int count;
546 rtc = container_of(timer, struct rtc_device, pie_timer);
547
548 period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
549 count = hrtimer_forward_now(timer, period);
550
551 rtc_handle_legacy_irq(rtc, count, RTC_PF);
552
553 return HRTIMER_RESTART;
554}
555
556/**
557 * rtc_update_irq - Triggered when a RTC interrupt occurs.
558 * @rtc: the rtc device
559 * @num: how many irqs are being reported (usually one)
560 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
561 * Context: any
562 */
563void rtc_update_irq(struct rtc_device *rtc,
564 unsigned long num, unsigned long events)
565{
566 schedule_work(&rtc->irqwork);
567}
568EXPORT_SYMBOL_GPL(rtc_update_irq);
569
570static int __rtc_match(struct device *dev, void *data)
571{
572 char *name = (char *)data;
573
574 if (strcmp(dev_name(dev), name) == 0)
575 return 1;
576 return 0;
577}
578
579struct rtc_device *rtc_class_open(char *name)
580{
581 struct device *dev;
582 struct rtc_device *rtc = NULL;
583
584 dev = class_find_device(rtc_class, NULL, name, __rtc_match);
585 if (dev)
586 rtc = to_rtc_device(dev);
587
588 if (rtc) {
589 if (!try_module_get(rtc->owner)) {
590 put_device(dev);
591 rtc = NULL;
592 }
593 }
594
595 return rtc;
596}
597EXPORT_SYMBOL_GPL(rtc_class_open);
598
599void rtc_class_close(struct rtc_device *rtc)
600{
601 module_put(rtc->owner);
602 put_device(&rtc->dev);
603}
604EXPORT_SYMBOL_GPL(rtc_class_close);
605
606int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
607{
608 int retval = -EBUSY;
609
610 if (task == NULL || task->func == NULL)
611 return -EINVAL;
612
613 /* Cannot register while the char dev is in use */
614 if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
615 return -EBUSY;
616
617 spin_lock_irq(&rtc->irq_task_lock);
618 if (rtc->irq_task == NULL) {
619 rtc->irq_task = task;
620 retval = 0;
621 }
622 spin_unlock_irq(&rtc->irq_task_lock);
623
624 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
625
626 return retval;
627}
628EXPORT_SYMBOL_GPL(rtc_irq_register);
629
630void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task)
631{
632 spin_lock_irq(&rtc->irq_task_lock);
633 if (rtc->irq_task == task)
634 rtc->irq_task = NULL;
635 spin_unlock_irq(&rtc->irq_task_lock);
636}
637EXPORT_SYMBOL_GPL(rtc_irq_unregister);
638
639static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
640{
641 /*
642 * We always cancel the timer here first, because otherwise
643 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
644 * when we manage to start the timer before the callback
645 * returns HRTIMER_RESTART.
646 *
647 * We cannot use hrtimer_cancel() here as a running callback
648 * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
649 * would spin forever.
650 */
651 if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
652 return -1;
653
654 if (enabled) {
655 ktime_t period = ktime_set(0, NSEC_PER_SEC / rtc->irq_freq);
656
657 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
658 }
659 return 0;
660}
661
662/**
663 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
664 * @rtc: the rtc device
665 * @task: currently registered with rtc_irq_register()
666 * @enabled: true to enable periodic IRQs
667 * Context: any
668 *
669 * Note that rtc_irq_set_freq() should previously have been used to
670 * specify the desired frequency of periodic IRQ task->func() callbacks.
671 */
672int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled)
673{
674 int err = 0;
675 unsigned long flags;
676
677retry:
678 spin_lock_irqsave(&rtc->irq_task_lock, flags);
679 if (rtc->irq_task != NULL && task == NULL)
680 err = -EBUSY;
681 if (rtc->irq_task != task)
682 err = -EACCES;
683 if (!err) {
684 if (rtc_update_hrtimer(rtc, enabled) < 0) {
685 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
686 cpu_relax();
687 goto retry;
688 }
689 rtc->pie_enabled = enabled;
690 }
691 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
692 return err;
693}
694EXPORT_SYMBOL_GPL(rtc_irq_set_state);
695
696/**
697 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
698 * @rtc: the rtc device
699 * @task: currently registered with rtc_irq_register()
700 * @freq: positive frequency with which task->func() will be called
701 * Context: any
702 *
703 * Note that rtc_irq_set_state() is used to enable or disable the
704 * periodic IRQs.
705 */
706int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
707{
708 int err = 0;
709 unsigned long flags;
710
711 if (freq <= 0 || freq > RTC_MAX_FREQ)
712 return -EINVAL;
713retry:
714 spin_lock_irqsave(&rtc->irq_task_lock, flags);
715 if (rtc->irq_task != NULL && task == NULL)
716 err = -EBUSY;
717 if (rtc->irq_task != task)
718 err = -EACCES;
719 if (!err) {
720 rtc->irq_freq = freq;
721 if (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0) {
722 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
723 cpu_relax();
724 goto retry;
725 }
726 }
727 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
728 return err;
729}
730EXPORT_SYMBOL_GPL(rtc_irq_set_freq);
731
732/**
733 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
734 * @rtc rtc device
735 * @timer timer being added.
736 *
737 * Enqueues a timer onto the rtc devices timerqueue and sets
738 * the next alarm event appropriately.
739 *
740 * Sets the enabled bit on the added timer.
741 *
742 * Must hold ops_lock for proper serialization of timerqueue
743 */
744static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
745{
746 timer->enabled = 1;
747 timerqueue_add(&rtc->timerqueue, &timer->node);
748 if (&timer->node == timerqueue_getnext(&rtc->timerqueue)) {
749 struct rtc_wkalrm alarm;
750 int err;
751 alarm.time = rtc_ktime_to_tm(timer->node.expires);
752 alarm.enabled = 1;
753 err = __rtc_set_alarm(rtc, &alarm);
754 if (err == -ETIME)
755 schedule_work(&rtc->irqwork);
756 else if (err) {
757 timerqueue_del(&rtc->timerqueue, &timer->node);
758 timer->enabled = 0;
759 return err;
760 }
761 }
762 return 0;
763}
764
765/**
766 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
767 * @rtc rtc device
768 * @timer timer being removed.
769 *
770 * Removes a timer onto the rtc devices timerqueue and sets
771 * the next alarm event appropriately.
772 *
773 * Clears the enabled bit on the removed timer.
774 *
775 * Must hold ops_lock for proper serialization of timerqueue
776 */
777static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
778{
779 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
780 timerqueue_del(&rtc->timerqueue, &timer->node);
781 timer->enabled = 0;
782 if (next == &timer->node) {
783 struct rtc_wkalrm alarm;
784 int err;
785 next = timerqueue_getnext(&rtc->timerqueue);
786 if (!next)
787 return;
788 alarm.time = rtc_ktime_to_tm(next->expires);
789 alarm.enabled = 1;
790 err = __rtc_set_alarm(rtc, &alarm);
791 if (err == -ETIME)
792 schedule_work(&rtc->irqwork);
793 }
794}
795
796/**
797 * rtc_timer_do_work - Expires rtc timers
798 * @rtc rtc device
799 * @timer timer being removed.
800 *
801 * Expires rtc timers. Reprograms next alarm event if needed.
802 * Called via worktask.
803 *
804 * Serializes access to timerqueue via ops_lock mutex
805 */
806void rtc_timer_do_work(struct work_struct *work)
807{
808 struct rtc_timer *timer;
809 struct timerqueue_node *next;
810 ktime_t now;
811 struct rtc_time tm;
812
813 struct rtc_device *rtc =
814 container_of(work, struct rtc_device, irqwork);
815
816 mutex_lock(&rtc->ops_lock);
817again:
818 __rtc_read_time(rtc, &tm);
819 now = rtc_tm_to_ktime(tm);
820 while ((next = timerqueue_getnext(&rtc->timerqueue))) {
821 if (next->expires.tv64 > now.tv64)
822 break;
823
824 /* expire timer */
825 timer = container_of(next, struct rtc_timer, node);
826 timerqueue_del(&rtc->timerqueue, &timer->node);
827 timer->enabled = 0;
828 if (timer->task.func)
829 timer->task.func(timer->task.private_data);
830
831 /* Re-add/fwd periodic timers */
832 if (ktime_to_ns(timer->period)) {
833 timer->node.expires = ktime_add(timer->node.expires,
834 timer->period);
835 timer->enabled = 1;
836 timerqueue_add(&rtc->timerqueue, &timer->node);
837 }
838 }
839
840 /* Set next alarm */
841 if (next) {
842 struct rtc_wkalrm alarm;
843 int err;
844 alarm.time = rtc_ktime_to_tm(next->expires);
845 alarm.enabled = 1;
846 err = __rtc_set_alarm(rtc, &alarm);
847 if (err == -ETIME)
848 goto again;
849 }
850
851 mutex_unlock(&rtc->ops_lock);
852}
853
854
855/* rtc_timer_init - Initializes an rtc_timer
856 * @timer: timer to be intiialized
857 * @f: function pointer to be called when timer fires
858 * @data: private data passed to function pointer
859 *
860 * Kernel interface to initializing an rtc_timer.
861 */
862void rtc_timer_init(struct rtc_timer *timer, void (*f)(void* p), void* data)
863{
864 timerqueue_init(&timer->node);
865 timer->enabled = 0;
866 timer->task.func = f;
867 timer->task.private_data = data;
868}
869
870/* rtc_timer_start - Sets an rtc_timer to fire in the future
871 * @ rtc: rtc device to be used
872 * @ timer: timer being set
873 * @ expires: time at which to expire the timer
874 * @ period: period that the timer will recur
875 *
876 * Kernel interface to set an rtc_timer
877 */
878int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer* timer,
879 ktime_t expires, ktime_t period)
880{
881 int ret = 0;
882 mutex_lock(&rtc->ops_lock);
883 if (timer->enabled)
884 rtc_timer_remove(rtc, timer);
885
886 timer->node.expires = expires;
887 timer->period = period;
888
889 ret = rtc_timer_enqueue(rtc, timer);
890
891 mutex_unlock(&rtc->ops_lock);
892 return ret;
893}
894
895/* rtc_timer_cancel - Stops an rtc_timer
896 * @ rtc: rtc device to be used
897 * @ timer: timer being set
898 *
899 * Kernel interface to cancel an rtc_timer
900 */
901int rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer* timer)
902{
903 int ret = 0;
904 mutex_lock(&rtc->ops_lock);
905 if (timer->enabled)
906 rtc_timer_remove(rtc, timer);
907 mutex_unlock(&rtc->ops_lock);
908 return ret;
909}
910
911
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * RTC subsystem, interface functions
4 *
5 * Copyright (C) 2005 Tower Technologies
6 * Author: Alessandro Zummo <a.zummo@towertech.it>
7 *
8 * based on arch/arm/common/rtctime.c
9 */
10
11#include <linux/rtc.h>
12#include <linux/sched.h>
13#include <linux/module.h>
14#include <linux/log2.h>
15#include <linux/workqueue.h>
16
17#define CREATE_TRACE_POINTS
18#include <trace/events/rtc.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 void rtc_add_offset(struct rtc_device *rtc, struct rtc_time *tm)
24{
25 time64_t secs;
26
27 if (!rtc->offset_secs)
28 return;
29
30 secs = rtc_tm_to_time64(tm);
31
32 /*
33 * Since the reading time values from RTC device are always in the RTC
34 * original valid range, but we need to skip the overlapped region
35 * between expanded range and original range, which is no need to add
36 * the offset.
37 */
38 if ((rtc->start_secs > rtc->range_min && secs >= rtc->start_secs) ||
39 (rtc->start_secs < rtc->range_min &&
40 secs <= (rtc->start_secs + rtc->range_max - rtc->range_min)))
41 return;
42
43 rtc_time64_to_tm(secs + rtc->offset_secs, tm);
44}
45
46static void rtc_subtract_offset(struct rtc_device *rtc, struct rtc_time *tm)
47{
48 time64_t secs;
49
50 if (!rtc->offset_secs)
51 return;
52
53 secs = rtc_tm_to_time64(tm);
54
55 /*
56 * If the setting time values are in the valid range of RTC hardware
57 * device, then no need to subtract the offset when setting time to RTC
58 * device. Otherwise we need to subtract the offset to make the time
59 * values are valid for RTC hardware device.
60 */
61 if (secs >= rtc->range_min && secs <= rtc->range_max)
62 return;
63
64 rtc_time64_to_tm(secs - rtc->offset_secs, tm);
65}
66
67static int rtc_valid_range(struct rtc_device *rtc, struct rtc_time *tm)
68{
69 if (rtc->range_min != rtc->range_max) {
70 time64_t time = rtc_tm_to_time64(tm);
71 time64_t range_min = rtc->set_start_time ? rtc->start_secs :
72 rtc->range_min;
73 time64_t range_max = rtc->set_start_time ?
74 (rtc->start_secs + rtc->range_max - rtc->range_min) :
75 rtc->range_max;
76
77 if (time < range_min || time > range_max)
78 return -ERANGE;
79 }
80
81 return 0;
82}
83
84static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
85{
86 int err;
87
88 if (!rtc->ops) {
89 err = -ENODEV;
90 } else if (!rtc->ops->read_time) {
91 err = -EINVAL;
92 } else {
93 memset(tm, 0, sizeof(struct rtc_time));
94 err = rtc->ops->read_time(rtc->dev.parent, tm);
95 if (err < 0) {
96 dev_dbg(&rtc->dev, "read_time: fail to read: %d\n",
97 err);
98 return err;
99 }
100
101 rtc_add_offset(rtc, tm);
102
103 err = rtc_valid_tm(tm);
104 if (err < 0)
105 dev_dbg(&rtc->dev, "read_time: rtc_time isn't valid\n");
106 }
107 return err;
108}
109
110int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
111{
112 int err;
113
114 err = mutex_lock_interruptible(&rtc->ops_lock);
115 if (err)
116 return err;
117
118 err = __rtc_read_time(rtc, tm);
119 mutex_unlock(&rtc->ops_lock);
120
121 trace_rtc_read_time(rtc_tm_to_time64(tm), err);
122 return err;
123}
124EXPORT_SYMBOL_GPL(rtc_read_time);
125
126int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
127{
128 int err;
129
130 err = rtc_valid_tm(tm);
131 if (err != 0)
132 return err;
133
134 err = rtc_valid_range(rtc, tm);
135 if (err)
136 return err;
137
138 rtc_subtract_offset(rtc, tm);
139
140 err = mutex_lock_interruptible(&rtc->ops_lock);
141 if (err)
142 return err;
143
144 if (!rtc->ops)
145 err = -ENODEV;
146 else if (rtc->ops->set_time)
147 err = rtc->ops->set_time(rtc->dev.parent, tm);
148 else
149 err = -EINVAL;
150
151 pm_stay_awake(rtc->dev.parent);
152 mutex_unlock(&rtc->ops_lock);
153 /* A timer might have just expired */
154 schedule_work(&rtc->irqwork);
155
156 trace_rtc_set_time(rtc_tm_to_time64(tm), err);
157 return err;
158}
159EXPORT_SYMBOL_GPL(rtc_set_time);
160
161static int rtc_read_alarm_internal(struct rtc_device *rtc,
162 struct rtc_wkalrm *alarm)
163{
164 int err;
165
166 err = mutex_lock_interruptible(&rtc->ops_lock);
167 if (err)
168 return err;
169
170 if (!rtc->ops) {
171 err = -ENODEV;
172 } else if (!rtc->ops->read_alarm) {
173 err = -EINVAL;
174 } else {
175 alarm->enabled = 0;
176 alarm->pending = 0;
177 alarm->time.tm_sec = -1;
178 alarm->time.tm_min = -1;
179 alarm->time.tm_hour = -1;
180 alarm->time.tm_mday = -1;
181 alarm->time.tm_mon = -1;
182 alarm->time.tm_year = -1;
183 alarm->time.tm_wday = -1;
184 alarm->time.tm_yday = -1;
185 alarm->time.tm_isdst = -1;
186 err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
187 }
188
189 mutex_unlock(&rtc->ops_lock);
190
191 trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
192 return err;
193}
194
195int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
196{
197 int err;
198 struct rtc_time before, now;
199 int first_time = 1;
200 time64_t t_now, t_alm;
201 enum { none, day, month, year } missing = none;
202 unsigned int days;
203
204 /* The lower level RTC driver may return -1 in some fields,
205 * creating invalid alarm->time values, for reasons like:
206 *
207 * - The hardware may not be capable of filling them in;
208 * many alarms match only on time-of-day fields, not
209 * day/month/year calendar data.
210 *
211 * - Some hardware uses illegal values as "wildcard" match
212 * values, which non-Linux firmware (like a BIOS) may try
213 * to set up as e.g. "alarm 15 minutes after each hour".
214 * Linux uses only oneshot alarms.
215 *
216 * When we see that here, we deal with it by using values from
217 * a current RTC timestamp for any missing (-1) values. The
218 * RTC driver prevents "periodic alarm" modes.
219 *
220 * But this can be racey, because some fields of the RTC timestamp
221 * may have wrapped in the interval since we read the RTC alarm,
222 * which would lead to us inserting inconsistent values in place
223 * of the -1 fields.
224 *
225 * Reading the alarm and timestamp in the reverse sequence
226 * would have the same race condition, and not solve the issue.
227 *
228 * So, we must first read the RTC timestamp,
229 * then read the RTC alarm value,
230 * and then read a second RTC timestamp.
231 *
232 * If any fields of the second timestamp have changed
233 * when compared with the first timestamp, then we know
234 * our timestamp may be inconsistent with that used by
235 * the low-level rtc_read_alarm_internal() function.
236 *
237 * So, when the two timestamps disagree, we just loop and do
238 * the process again to get a fully consistent set of values.
239 *
240 * This could all instead be done in the lower level driver,
241 * but since more than one lower level RTC implementation needs it,
242 * then it's probably best best to do it here instead of there..
243 */
244
245 /* Get the "before" timestamp */
246 err = rtc_read_time(rtc, &before);
247 if (err < 0)
248 return err;
249 do {
250 if (!first_time)
251 memcpy(&before, &now, sizeof(struct rtc_time));
252 first_time = 0;
253
254 /* get the RTC alarm values, which may be incomplete */
255 err = rtc_read_alarm_internal(rtc, alarm);
256 if (err)
257 return err;
258
259 /* full-function RTCs won't have such missing fields */
260 if (rtc_valid_tm(&alarm->time) == 0) {
261 rtc_add_offset(rtc, &alarm->time);
262 return 0;
263 }
264
265 /* get the "after" timestamp, to detect wrapped fields */
266 err = rtc_read_time(rtc, &now);
267 if (err < 0)
268 return err;
269
270 /* note that tm_sec is a "don't care" value here: */
271 } while (before.tm_min != now.tm_min ||
272 before.tm_hour != now.tm_hour ||
273 before.tm_mon != now.tm_mon ||
274 before.tm_year != now.tm_year);
275
276 /* Fill in the missing alarm fields using the timestamp; we
277 * know there's at least one since alarm->time is invalid.
278 */
279 if (alarm->time.tm_sec == -1)
280 alarm->time.tm_sec = now.tm_sec;
281 if (alarm->time.tm_min == -1)
282 alarm->time.tm_min = now.tm_min;
283 if (alarm->time.tm_hour == -1)
284 alarm->time.tm_hour = now.tm_hour;
285
286 /* For simplicity, only support date rollover for now */
287 if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) {
288 alarm->time.tm_mday = now.tm_mday;
289 missing = day;
290 }
291 if ((unsigned int)alarm->time.tm_mon >= 12) {
292 alarm->time.tm_mon = now.tm_mon;
293 if (missing == none)
294 missing = month;
295 }
296 if (alarm->time.tm_year == -1) {
297 alarm->time.tm_year = now.tm_year;
298 if (missing == none)
299 missing = year;
300 }
301
302 /* Can't proceed if alarm is still invalid after replacing
303 * missing fields.
304 */
305 err = rtc_valid_tm(&alarm->time);
306 if (err)
307 goto done;
308
309 /* with luck, no rollover is needed */
310 t_now = rtc_tm_to_time64(&now);
311 t_alm = rtc_tm_to_time64(&alarm->time);
312 if (t_now < t_alm)
313 goto done;
314
315 switch (missing) {
316 /* 24 hour rollover ... if it's now 10am Monday, an alarm that
317 * that will trigger at 5am will do so at 5am Tuesday, which
318 * could also be in the next month or year. This is a common
319 * case, especially for PCs.
320 */
321 case day:
322 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
323 t_alm += 24 * 60 * 60;
324 rtc_time64_to_tm(t_alm, &alarm->time);
325 break;
326
327 /* Month rollover ... if it's the 31th, an alarm on the 3rd will
328 * be next month. An alarm matching on the 30th, 29th, or 28th
329 * may end up in the month after that! Many newer PCs support
330 * this type of alarm.
331 */
332 case month:
333 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
334 do {
335 if (alarm->time.tm_mon < 11) {
336 alarm->time.tm_mon++;
337 } else {
338 alarm->time.tm_mon = 0;
339 alarm->time.tm_year++;
340 }
341 days = rtc_month_days(alarm->time.tm_mon,
342 alarm->time.tm_year);
343 } while (days < alarm->time.tm_mday);
344 break;
345
346 /* Year rollover ... easy except for leap years! */
347 case year:
348 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
349 do {
350 alarm->time.tm_year++;
351 } while (!is_leap_year(alarm->time.tm_year + 1900) &&
352 rtc_valid_tm(&alarm->time) != 0);
353 break;
354
355 default:
356 dev_warn(&rtc->dev, "alarm rollover not handled\n");
357 }
358
359 err = rtc_valid_tm(&alarm->time);
360
361done:
362 if (err)
363 dev_warn(&rtc->dev, "invalid alarm value: %ptR\n",
364 &alarm->time);
365
366 return err;
367}
368
369int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
370{
371 int err;
372
373 err = mutex_lock_interruptible(&rtc->ops_lock);
374 if (err)
375 return err;
376 if (!rtc->ops) {
377 err = -ENODEV;
378 } else if (!rtc->ops->read_alarm) {
379 err = -EINVAL;
380 } else {
381 memset(alarm, 0, sizeof(struct rtc_wkalrm));
382 alarm->enabled = rtc->aie_timer.enabled;
383 alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
384 }
385 mutex_unlock(&rtc->ops_lock);
386
387 trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
388 return err;
389}
390EXPORT_SYMBOL_GPL(rtc_read_alarm);
391
392static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
393{
394 struct rtc_time tm;
395 time64_t now, scheduled;
396 int err;
397
398 err = rtc_valid_tm(&alarm->time);
399 if (err)
400 return err;
401
402 scheduled = rtc_tm_to_time64(&alarm->time);
403
404 /* Make sure we're not setting alarms in the past */
405 err = __rtc_read_time(rtc, &tm);
406 if (err)
407 return err;
408 now = rtc_tm_to_time64(&tm);
409 if (scheduled <= now)
410 return -ETIME;
411 /*
412 * XXX - We just checked to make sure the alarm time is not
413 * in the past, but there is still a race window where if
414 * the is alarm set for the next second and the second ticks
415 * over right here, before we set the alarm.
416 */
417
418 rtc_subtract_offset(rtc, &alarm->time);
419
420 if (!rtc->ops)
421 err = -ENODEV;
422 else if (!rtc->ops->set_alarm)
423 err = -EINVAL;
424 else
425 err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
426
427 trace_rtc_set_alarm(rtc_tm_to_time64(&alarm->time), err);
428 return err;
429}
430
431int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
432{
433 int err;
434
435 if (!rtc->ops)
436 return -ENODEV;
437 else if (!rtc->ops->set_alarm)
438 return -EINVAL;
439
440 err = rtc_valid_tm(&alarm->time);
441 if (err != 0)
442 return err;
443
444 err = rtc_valid_range(rtc, &alarm->time);
445 if (err)
446 return err;
447
448 err = mutex_lock_interruptible(&rtc->ops_lock);
449 if (err)
450 return err;
451 if (rtc->aie_timer.enabled)
452 rtc_timer_remove(rtc, &rtc->aie_timer);
453
454 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
455 rtc->aie_timer.period = 0;
456 if (alarm->enabled)
457 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
458
459 mutex_unlock(&rtc->ops_lock);
460
461 return err;
462}
463EXPORT_SYMBOL_GPL(rtc_set_alarm);
464
465/* Called once per device from rtc_device_register */
466int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
467{
468 int err;
469 struct rtc_time now;
470
471 err = rtc_valid_tm(&alarm->time);
472 if (err != 0)
473 return err;
474
475 err = rtc_read_time(rtc, &now);
476 if (err)
477 return err;
478
479 err = mutex_lock_interruptible(&rtc->ops_lock);
480 if (err)
481 return err;
482
483 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
484 rtc->aie_timer.period = 0;
485
486 /* Alarm has to be enabled & in the future for us to enqueue it */
487 if (alarm->enabled && (rtc_tm_to_ktime(now) <
488 rtc->aie_timer.node.expires)) {
489 rtc->aie_timer.enabled = 1;
490 timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
491 trace_rtc_timer_enqueue(&rtc->aie_timer);
492 }
493 mutex_unlock(&rtc->ops_lock);
494 return err;
495}
496EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
497
498int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
499{
500 int err;
501
502 err = mutex_lock_interruptible(&rtc->ops_lock);
503 if (err)
504 return err;
505
506 if (rtc->aie_timer.enabled != enabled) {
507 if (enabled)
508 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
509 else
510 rtc_timer_remove(rtc, &rtc->aie_timer);
511 }
512
513 if (err)
514 /* nothing */;
515 else if (!rtc->ops)
516 err = -ENODEV;
517 else if (!rtc->ops->alarm_irq_enable)
518 err = -EINVAL;
519 else
520 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
521
522 mutex_unlock(&rtc->ops_lock);
523
524 trace_rtc_alarm_irq_enable(enabled, err);
525 return err;
526}
527EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
528
529int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
530{
531 int err;
532
533 err = mutex_lock_interruptible(&rtc->ops_lock);
534 if (err)
535 return err;
536
537#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
538 if (enabled == 0 && rtc->uie_irq_active) {
539 mutex_unlock(&rtc->ops_lock);
540 return rtc_dev_update_irq_enable_emul(rtc, 0);
541 }
542#endif
543 /* make sure we're changing state */
544 if (rtc->uie_rtctimer.enabled == enabled)
545 goto out;
546
547 if (rtc->uie_unsupported) {
548 err = -EINVAL;
549 goto out;
550 }
551
552 if (enabled) {
553 struct rtc_time tm;
554 ktime_t now, onesec;
555
556 __rtc_read_time(rtc, &tm);
557 onesec = ktime_set(1, 0);
558 now = rtc_tm_to_ktime(tm);
559 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
560 rtc->uie_rtctimer.period = ktime_set(1, 0);
561 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
562 } else {
563 rtc_timer_remove(rtc, &rtc->uie_rtctimer);
564 }
565
566out:
567 mutex_unlock(&rtc->ops_lock);
568#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
569 /*
570 * Enable emulation if the driver returned -EINVAL to signal that it has
571 * been configured without interrupts or they are not available at the
572 * moment.
573 */
574 if (err == -EINVAL)
575 err = rtc_dev_update_irq_enable_emul(rtc, enabled);
576#endif
577 return err;
578}
579EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
580
581/**
582 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
583 * @rtc: pointer to the rtc device
584 *
585 * This function is called when an AIE, UIE or PIE mode interrupt
586 * has occurred (or been emulated).
587 *
588 */
589void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
590{
591 unsigned long flags;
592
593 /* mark one irq of the appropriate mode */
594 spin_lock_irqsave(&rtc->irq_lock, flags);
595 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF | mode);
596 spin_unlock_irqrestore(&rtc->irq_lock, flags);
597
598 wake_up_interruptible(&rtc->irq_queue);
599 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
600}
601
602/**
603 * rtc_aie_update_irq - AIE mode rtctimer hook
604 * @rtc: pointer to the rtc_device
605 *
606 * This functions is called when the aie_timer expires.
607 */
608void rtc_aie_update_irq(struct rtc_device *rtc)
609{
610 rtc_handle_legacy_irq(rtc, 1, RTC_AF);
611}
612
613/**
614 * rtc_uie_update_irq - UIE mode rtctimer hook
615 * @rtc: pointer to the rtc_device
616 *
617 * This functions is called when the uie_timer expires.
618 */
619void rtc_uie_update_irq(struct rtc_device *rtc)
620{
621 rtc_handle_legacy_irq(rtc, 1, RTC_UF);
622}
623
624/**
625 * rtc_pie_update_irq - PIE mode hrtimer hook
626 * @timer: pointer to the pie mode hrtimer
627 *
628 * This function is used to emulate PIE mode interrupts
629 * using an hrtimer. This function is called when the periodic
630 * hrtimer expires.
631 */
632enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
633{
634 struct rtc_device *rtc;
635 ktime_t period;
636 u64 count;
637
638 rtc = container_of(timer, struct rtc_device, pie_timer);
639
640 period = NSEC_PER_SEC / rtc->irq_freq;
641 count = hrtimer_forward_now(timer, period);
642
643 rtc_handle_legacy_irq(rtc, count, RTC_PF);
644
645 return HRTIMER_RESTART;
646}
647
648/**
649 * rtc_update_irq - Triggered when a RTC interrupt occurs.
650 * @rtc: the rtc device
651 * @num: how many irqs are being reported (usually one)
652 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
653 * Context: any
654 */
655void rtc_update_irq(struct rtc_device *rtc,
656 unsigned long num, unsigned long events)
657{
658 if (IS_ERR_OR_NULL(rtc))
659 return;
660
661 pm_stay_awake(rtc->dev.parent);
662 schedule_work(&rtc->irqwork);
663}
664EXPORT_SYMBOL_GPL(rtc_update_irq);
665
666struct rtc_device *rtc_class_open(const char *name)
667{
668 struct device *dev;
669 struct rtc_device *rtc = NULL;
670
671 dev = class_find_device_by_name(rtc_class, name);
672 if (dev)
673 rtc = to_rtc_device(dev);
674
675 if (rtc) {
676 if (!try_module_get(rtc->owner)) {
677 put_device(dev);
678 rtc = NULL;
679 }
680 }
681
682 return rtc;
683}
684EXPORT_SYMBOL_GPL(rtc_class_open);
685
686void rtc_class_close(struct rtc_device *rtc)
687{
688 module_put(rtc->owner);
689 put_device(&rtc->dev);
690}
691EXPORT_SYMBOL_GPL(rtc_class_close);
692
693static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
694{
695 /*
696 * We always cancel the timer here first, because otherwise
697 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
698 * when we manage to start the timer before the callback
699 * returns HRTIMER_RESTART.
700 *
701 * We cannot use hrtimer_cancel() here as a running callback
702 * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
703 * would spin forever.
704 */
705 if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
706 return -1;
707
708 if (enabled) {
709 ktime_t period = NSEC_PER_SEC / rtc->irq_freq;
710
711 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
712 }
713 return 0;
714}
715
716/**
717 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
718 * @rtc: the rtc device
719 * @enabled: true to enable periodic IRQs
720 * Context: any
721 *
722 * Note that rtc_irq_set_freq() should previously have been used to
723 * specify the desired frequency of periodic IRQ.
724 */
725int rtc_irq_set_state(struct rtc_device *rtc, int enabled)
726{
727 int err = 0;
728
729 while (rtc_update_hrtimer(rtc, enabled) < 0)
730 cpu_relax();
731
732 rtc->pie_enabled = enabled;
733
734 trace_rtc_irq_set_state(enabled, err);
735 return err;
736}
737
738/**
739 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
740 * @rtc: the rtc device
741 * @freq: positive frequency
742 * Context: any
743 *
744 * Note that rtc_irq_set_state() is used to enable or disable the
745 * periodic IRQs.
746 */
747int rtc_irq_set_freq(struct rtc_device *rtc, int freq)
748{
749 int err = 0;
750
751 if (freq <= 0 || freq > RTC_MAX_FREQ)
752 return -EINVAL;
753
754 rtc->irq_freq = freq;
755 while (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0)
756 cpu_relax();
757
758 trace_rtc_irq_set_freq(freq, err);
759 return err;
760}
761
762/**
763 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
764 * @rtc rtc device
765 * @timer timer being added.
766 *
767 * Enqueues a timer onto the rtc devices timerqueue and sets
768 * the next alarm event appropriately.
769 *
770 * Sets the enabled bit on the added timer.
771 *
772 * Must hold ops_lock for proper serialization of timerqueue
773 */
774static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
775{
776 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
777 struct rtc_time tm;
778 ktime_t now;
779
780 timer->enabled = 1;
781 __rtc_read_time(rtc, &tm);
782 now = rtc_tm_to_ktime(tm);
783
784 /* Skip over expired timers */
785 while (next) {
786 if (next->expires >= now)
787 break;
788 next = timerqueue_iterate_next(next);
789 }
790
791 timerqueue_add(&rtc->timerqueue, &timer->node);
792 trace_rtc_timer_enqueue(timer);
793 if (!next || ktime_before(timer->node.expires, next->expires)) {
794 struct rtc_wkalrm alarm;
795 int err;
796
797 alarm.time = rtc_ktime_to_tm(timer->node.expires);
798 alarm.enabled = 1;
799 err = __rtc_set_alarm(rtc, &alarm);
800 if (err == -ETIME) {
801 pm_stay_awake(rtc->dev.parent);
802 schedule_work(&rtc->irqwork);
803 } else if (err) {
804 timerqueue_del(&rtc->timerqueue, &timer->node);
805 trace_rtc_timer_dequeue(timer);
806 timer->enabled = 0;
807 return err;
808 }
809 }
810 return 0;
811}
812
813static void rtc_alarm_disable(struct rtc_device *rtc)
814{
815 if (!rtc->ops || !rtc->ops->alarm_irq_enable)
816 return;
817
818 rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
819 trace_rtc_alarm_irq_enable(0, 0);
820}
821
822/**
823 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
824 * @rtc rtc device
825 * @timer timer being removed.
826 *
827 * Removes a timer onto the rtc devices timerqueue and sets
828 * the next alarm event appropriately.
829 *
830 * Clears the enabled bit on the removed timer.
831 *
832 * Must hold ops_lock for proper serialization of timerqueue
833 */
834static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
835{
836 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
837
838 timerqueue_del(&rtc->timerqueue, &timer->node);
839 trace_rtc_timer_dequeue(timer);
840 timer->enabled = 0;
841 if (next == &timer->node) {
842 struct rtc_wkalrm alarm;
843 int err;
844
845 next = timerqueue_getnext(&rtc->timerqueue);
846 if (!next) {
847 rtc_alarm_disable(rtc);
848 return;
849 }
850 alarm.time = rtc_ktime_to_tm(next->expires);
851 alarm.enabled = 1;
852 err = __rtc_set_alarm(rtc, &alarm);
853 if (err == -ETIME) {
854 pm_stay_awake(rtc->dev.parent);
855 schedule_work(&rtc->irqwork);
856 }
857 }
858}
859
860/**
861 * rtc_timer_do_work - Expires rtc timers
862 * @rtc rtc device
863 * @timer timer being removed.
864 *
865 * Expires rtc timers. Reprograms next alarm event if needed.
866 * Called via worktask.
867 *
868 * Serializes access to timerqueue via ops_lock mutex
869 */
870void rtc_timer_do_work(struct work_struct *work)
871{
872 struct rtc_timer *timer;
873 struct timerqueue_node *next;
874 ktime_t now;
875 struct rtc_time tm;
876
877 struct rtc_device *rtc =
878 container_of(work, struct rtc_device, irqwork);
879
880 mutex_lock(&rtc->ops_lock);
881again:
882 __rtc_read_time(rtc, &tm);
883 now = rtc_tm_to_ktime(tm);
884 while ((next = timerqueue_getnext(&rtc->timerqueue))) {
885 if (next->expires > now)
886 break;
887
888 /* expire timer */
889 timer = container_of(next, struct rtc_timer, node);
890 timerqueue_del(&rtc->timerqueue, &timer->node);
891 trace_rtc_timer_dequeue(timer);
892 timer->enabled = 0;
893 if (timer->func)
894 timer->func(timer->rtc);
895
896 trace_rtc_timer_fired(timer);
897 /* Re-add/fwd periodic timers */
898 if (ktime_to_ns(timer->period)) {
899 timer->node.expires = ktime_add(timer->node.expires,
900 timer->period);
901 timer->enabled = 1;
902 timerqueue_add(&rtc->timerqueue, &timer->node);
903 trace_rtc_timer_enqueue(timer);
904 }
905 }
906
907 /* Set next alarm */
908 if (next) {
909 struct rtc_wkalrm alarm;
910 int err;
911 int retry = 3;
912
913 alarm.time = rtc_ktime_to_tm(next->expires);
914 alarm.enabled = 1;
915reprogram:
916 err = __rtc_set_alarm(rtc, &alarm);
917 if (err == -ETIME) {
918 goto again;
919 } else if (err) {
920 if (retry-- > 0)
921 goto reprogram;
922
923 timer = container_of(next, struct rtc_timer, node);
924 timerqueue_del(&rtc->timerqueue, &timer->node);
925 trace_rtc_timer_dequeue(timer);
926 timer->enabled = 0;
927 dev_err(&rtc->dev, "__rtc_set_alarm: err=%d\n", err);
928 goto again;
929 }
930 } else {
931 rtc_alarm_disable(rtc);
932 }
933
934 pm_relax(rtc->dev.parent);
935 mutex_unlock(&rtc->ops_lock);
936}
937
938/* rtc_timer_init - Initializes an rtc_timer
939 * @timer: timer to be intiialized
940 * @f: function pointer to be called when timer fires
941 * @rtc: pointer to the rtc_device
942 *
943 * Kernel interface to initializing an rtc_timer.
944 */
945void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
946 struct rtc_device *rtc)
947{
948 timerqueue_init(&timer->node);
949 timer->enabled = 0;
950 timer->func = f;
951 timer->rtc = rtc;
952}
953
954/* rtc_timer_start - Sets an rtc_timer to fire in the future
955 * @ rtc: rtc device to be used
956 * @ timer: timer being set
957 * @ expires: time at which to expire the timer
958 * @ period: period that the timer will recur
959 *
960 * Kernel interface to set an rtc_timer
961 */
962int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
963 ktime_t expires, ktime_t period)
964{
965 int ret = 0;
966
967 mutex_lock(&rtc->ops_lock);
968 if (timer->enabled)
969 rtc_timer_remove(rtc, timer);
970
971 timer->node.expires = expires;
972 timer->period = period;
973
974 ret = rtc_timer_enqueue(rtc, timer);
975
976 mutex_unlock(&rtc->ops_lock);
977 return ret;
978}
979
980/* rtc_timer_cancel - Stops an rtc_timer
981 * @ rtc: rtc device to be used
982 * @ timer: timer being set
983 *
984 * Kernel interface to cancel an rtc_timer
985 */
986void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
987{
988 mutex_lock(&rtc->ops_lock);
989 if (timer->enabled)
990 rtc_timer_remove(rtc, timer);
991 mutex_unlock(&rtc->ops_lock);
992}
993
994/**
995 * rtc_read_offset - Read the amount of rtc offset in parts per billion
996 * @ rtc: rtc device to be used
997 * @ offset: the offset in parts per billion
998 *
999 * see below for details.
1000 *
1001 * Kernel interface to read rtc clock offset
1002 * Returns 0 on success, or a negative number on error.
1003 * If read_offset() is not implemented for the rtc, return -EINVAL
1004 */
1005int rtc_read_offset(struct rtc_device *rtc, long *offset)
1006{
1007 int ret;
1008
1009 if (!rtc->ops)
1010 return -ENODEV;
1011
1012 if (!rtc->ops->read_offset)
1013 return -EINVAL;
1014
1015 mutex_lock(&rtc->ops_lock);
1016 ret = rtc->ops->read_offset(rtc->dev.parent, offset);
1017 mutex_unlock(&rtc->ops_lock);
1018
1019 trace_rtc_read_offset(*offset, ret);
1020 return ret;
1021}
1022
1023/**
1024 * rtc_set_offset - Adjusts the duration of the average second
1025 * @ rtc: rtc device to be used
1026 * @ offset: the offset in parts per billion
1027 *
1028 * Some rtc's allow an adjustment to the average duration of a second
1029 * to compensate for differences in the actual clock rate due to temperature,
1030 * the crystal, capacitor, etc.
1031 *
1032 * The adjustment applied is as follows:
1033 * t = t0 * (1 + offset * 1e-9)
1034 * where t0 is the measured length of 1 RTC second with offset = 0
1035 *
1036 * Kernel interface to adjust an rtc clock offset.
1037 * Return 0 on success, or a negative number on error.
1038 * If the rtc offset is not setable (or not implemented), return -EINVAL
1039 */
1040int rtc_set_offset(struct rtc_device *rtc, long offset)
1041{
1042 int ret;
1043
1044 if (!rtc->ops)
1045 return -ENODEV;
1046
1047 if (!rtc->ops->set_offset)
1048 return -EINVAL;
1049
1050 mutex_lock(&rtc->ops_lock);
1051 ret = rtc->ops->set_offset(rtc->dev.parent, offset);
1052 mutex_unlock(&rtc->ops_lock);
1053
1054 trace_rtc_set_offset(offset, ret);
1055 return ret;
1056}