projects/linux·blob v5.14 · refs

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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * RTC subsystem, interface functions
4 *
5 * Copyright (C) 2005 Tower Technologies
6 * Author: Alessandro Zummo <[email protected]>
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 timeu64_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, uie;
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#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
141 uie = rtc->uie_rtctimer.enabled || rtc->uie_irq_active;
142#else
143 uie = rtc->uie_rtctimer.enabled;
144#endif
145 if (uie) {
146 err = rtc_update_irq_enable(rtc, 0);
147 if (err)
148 return err;
149 }
150
151 err = mutex_lock_interruptible(&rtc->ops_lock);
152 if (err)
153 return err;
154
155 if (!rtc->ops)
156 err = -ENODEV;
157 else if (rtc->ops->set_time)
158 err = rtc->ops->set_time(rtc->dev.parent, tm);
159 else
160 err = -EINVAL;
161
162 pm_stay_awake(rtc->dev.parent);
163 mutex_unlock(&rtc->ops_lock);
164 /* A timer might have just expired */
165 schedule_work(&rtc->irqwork);
166
167 if (uie) {
168 err = rtc_update_irq_enable(rtc, 1);
169 if (err)
170 return err;
171 }
172
173 trace_rtc_set_time(rtc_tm_to_time64(tm), err);
174 return err;
175}
176EXPORT_SYMBOL_GPL(rtc_set_time);
177
178static int rtc_read_alarm_internal(struct rtc_device *rtc,
179 struct rtc_wkalrm *alarm)
180{
181 int err;
182
183 err = mutex_lock_interruptible(&rtc->ops_lock);
184 if (err)
185 return err;
186
187 if (!rtc->ops) {
188 err = -ENODEV;
189 } else if (!test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->read_alarm) {
190 err = -EINVAL;
191 } else {
192 alarm->enabled = 0;
193 alarm->pending = 0;
194 alarm->time.tm_sec = -1;
195 alarm->time.tm_min = -1;
196 alarm->time.tm_hour = -1;
197 alarm->time.tm_mday = -1;
198 alarm->time.tm_mon = -1;
199 alarm->time.tm_year = -1;
200 alarm->time.tm_wday = -1;
201 alarm->time.tm_yday = -1;
202 alarm->time.tm_isdst = -1;
203 err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
204 }
205
206 mutex_unlock(&rtc->ops_lock);
207
208 trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
209 return err;
210}
211
212int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
213{
214 int err;
215 struct rtc_time before, now;
216 int first_time = 1;
217 time64_t t_now, t_alm;
218 enum { none, day, month, year } missing = none;
219 unsigned int days;
220
221 /* The lower level RTC driver may return -1 in some fields,
222 * creating invalid alarm->time values, for reasons like:
223 *
224 * - The hardware may not be capable of filling them in;
225 * many alarms match only on time-of-day fields, not
226 * day/month/year calendar data.
227 *
228 * - Some hardware uses illegal values as "wildcard" match
229 * values, which non-Linux firmware (like a BIOS) may try
230 * to set up as e.g. "alarm 15 minutes after each hour".
231 * Linux uses only oneshot alarms.
232 *
233 * When we see that here, we deal with it by using values from
234 * a current RTC timestamp for any missing (-1) values. The
235 * RTC driver prevents "periodic alarm" modes.
236 *
237 * But this can be racey, because some fields of the RTC timestamp
238 * may have wrapped in the interval since we read the RTC alarm,
239 * which would lead to us inserting inconsistent values in place
240 * of the -1 fields.
241 *
242 * Reading the alarm and timestamp in the reverse sequence
243 * would have the same race condition, and not solve the issue.
244 *
245 * So, we must first read the RTC timestamp,
246 * then read the RTC alarm value,
247 * and then read a second RTC timestamp.
248 *
249 * If any fields of the second timestamp have changed
250 * when compared with the first timestamp, then we know
251 * our timestamp may be inconsistent with that used by
252 * the low-level rtc_read_alarm_internal() function.
253 *
254 * So, when the two timestamps disagree, we just loop and do
255 * the process again to get a fully consistent set of values.
256 *
257 * This could all instead be done in the lower level driver,
258 * but since more than one lower level RTC implementation needs it,
259 * then it's probably best best to do it here instead of there..
260 */
261
262 /* Get the "before" timestamp */
263 err = rtc_read_time(rtc, &before);
264 if (err < 0)
265 return err;
266 do {
267 if (!first_time)
268 memcpy(&before, &now, sizeof(struct rtc_time));
269 first_time = 0;
270
271 /* get the RTC alarm values, which may be incomplete */
272 err = rtc_read_alarm_internal(rtc, alarm);
273 if (err)
274 return err;
275
276 /* full-function RTCs won't have such missing fields */
277 if (rtc_valid_tm(&alarm->time) == 0) {
278 rtc_add_offset(rtc, &alarm->time);
279 return 0;
280 }
281
282 /* get the "after" timestamp, to detect wrapped fields */
283 err = rtc_read_time(rtc, &now);
284 if (err < 0)
285 return err;
286
287 /* note that tm_sec is a "don't care" value here: */
288 } while (before.tm_min != now.tm_min ||
289 before.tm_hour != now.tm_hour ||
290 before.tm_mon != now.tm_mon ||
291 before.tm_year != now.tm_year);
292
293 /* Fill in the missing alarm fields using the timestamp; we
294 * know there's at least one since alarm->time is invalid.
295 */
296 if (alarm->time.tm_sec == -1)
297 alarm->time.tm_sec = now.tm_sec;
298 if (alarm->time.tm_min == -1)
299 alarm->time.tm_min = now.tm_min;
300 if (alarm->time.tm_hour == -1)
301 alarm->time.tm_hour = now.tm_hour;
302
303 /* For simplicity, only support date rollover for now */
304 if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) {
305 alarm->time.tm_mday = now.tm_mday;
306 missing = day;
307 }
308 if ((unsigned int)alarm->time.tm_mon >= 12) {
309 alarm->time.tm_mon = now.tm_mon;
310 if (missing == none)
311 missing = month;
312 }
313 if (alarm->time.tm_year == -1) {
314 alarm->time.tm_year = now.tm_year;
315 if (missing == none)
316 missing = year;
317 }
318
319 /* Can't proceed if alarm is still invalid after replacing
320 * missing fields.
321 */
322 err = rtc_valid_tm(&alarm->time);
323 if (err)
324 goto done;
325
326 /* with luck, no rollover is needed */
327 t_now = rtc_tm_to_time64(&now);
328 t_alm = rtc_tm_to_time64(&alarm->time);
329 if (t_now < t_alm)
330 goto done;
331
332 switch (missing) {
333 /* 24 hour rollover ... if it's now 10am Monday, an alarm that
334 * that will trigger at 5am will do so at 5am Tuesday, which
335 * could also be in the next month or year. This is a common
336 * case, especially for PCs.
337 */
338 case day:
339 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
340 t_alm += 24 * 60 * 60;
341 rtc_time64_to_tm(t_alm, &alarm->time);
342 break;
343
344 /* Month rollover ... if it's the 31th, an alarm on the 3rd will
345 * be next month. An alarm matching on the 30th, 29th, or 28th
346 * may end up in the month after that! Many newer PCs support
347 * this type of alarm.
348 */
349 case month:
350 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
351 do {
352 if (alarm->time.tm_mon < 11) {
353 alarm->time.tm_mon++;
354 } else {
355 alarm->time.tm_mon = 0;
356 alarm->time.tm_year++;
357 }
358 days = rtc_month_days(alarm->time.tm_mon,
359 alarm->time.tm_year);
360 } while (days < alarm->time.tm_mday);
361 break;
362
363 /* Year rollover ... easy except for leap years! */
364 case year:
365 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
366 do {
367 alarm->time.tm_year++;
368 } while (!is_leap_year(alarm->time.tm_year + 1900) &&
369 rtc_valid_tm(&alarm->time) != 0);
370 break;
371
372 default:
373 dev_warn(&rtc->dev, "alarm rollover not handled\n");
374 }
375
376 err = rtc_valid_tm(&alarm->time);
377
378done:
379 if (err)
380 dev_warn(&rtc->dev, "invalid alarm value: %ptR\n",
381 &alarm->time);
382
383 return err;
384}
385
386int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
387{
388 int err;
389
390 err = mutex_lock_interruptible(&rtc->ops_lock);
391 if (err)
392 return err;
393 if (!rtc->ops) {
394 err = -ENODEV;
395 } else if (!test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->read_alarm) {
396 err = -EINVAL;
397 } else {
398 memset(alarm, 0, sizeof(struct rtc_wkalrm));
399 alarm->enabled = rtc->aie_timer.enabled;
400 alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
401 }
402 mutex_unlock(&rtc->ops_lock);
403
404 trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
405 return err;
406}
407EXPORT_SYMBOL_GPL(rtc_read_alarm);
408
409static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
410{
411 struct rtc_time tm;
412 time64_t now, scheduled;
413 int err;
414
415 err = rtc_valid_tm(&alarm->time);
416 if (err)
417 return err;
418
419 scheduled = rtc_tm_to_time64(&alarm->time);
420
421 /* Make sure we're not setting alarms in the past */
422 err = __rtc_read_time(rtc, &tm);
423 if (err)
424 return err;
425 now = rtc_tm_to_time64(&tm);
426 if (scheduled <= now)
427 return -ETIME;
428 /*
429 * XXX - We just checked to make sure the alarm time is not
430 * in the past, but there is still a race window where if
431 * the is alarm set for the next second and the second ticks
432 * over right here, before we set the alarm.
433 */
434
435 rtc_subtract_offset(rtc, &alarm->time);
436
437 if (!rtc->ops)
438 err = -ENODEV;
439 else if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
440 err = -EINVAL;
441 else
442 err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
443
444 trace_rtc_set_alarm(rtc_tm_to_time64(&alarm->time), err);
445 return err;
446}
447
448int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
449{
450 int err;
451
452 if (!rtc->ops)
453 return -ENODEV;
454 else if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
455 return -EINVAL;
456
457 err = rtc_valid_tm(&alarm->time);
458 if (err != 0)
459 return err;
460
461 err = rtc_valid_range(rtc, &alarm->time);
462 if (err)
463 return err;
464
465 err = mutex_lock_interruptible(&rtc->ops_lock);
466 if (err)
467 return err;
468 if (rtc->aie_timer.enabled)
469 rtc_timer_remove(rtc, &rtc->aie_timer);
470
471 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
472 rtc->aie_timer.period = 0;
473 if (alarm->enabled)
474 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
475
476 mutex_unlock(&rtc->ops_lock);
477
478 return err;
479}
480EXPORT_SYMBOL_GPL(rtc_set_alarm);
481
482/* Called once per device from rtc_device_register */
483int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
484{
485 int err;
486 struct rtc_time now;
487
488 err = rtc_valid_tm(&alarm->time);
489 if (err != 0)
490 return err;
491
492 err = rtc_read_time(rtc, &now);
493 if (err)
494 return err;
495
496 err = mutex_lock_interruptible(&rtc->ops_lock);
497 if (err)
498 return err;
499
500 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
501 rtc->aie_timer.period = 0;
502
503 /* Alarm has to be enabled & in the future for us to enqueue it */
504 if (alarm->enabled && (rtc_tm_to_ktime(now) <
505 rtc->aie_timer.node.expires)) {
506 rtc->aie_timer.enabled = 1;
507 timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
508 trace_rtc_timer_enqueue(&rtc->aie_timer);
509 }
510 mutex_unlock(&rtc->ops_lock);
511 return err;
512}
513EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
514
515int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
516{
517 int err;
518
519 err = mutex_lock_interruptible(&rtc->ops_lock);
520 if (err)
521 return err;
522
523 if (rtc->aie_timer.enabled != enabled) {
524 if (enabled)
525 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
526 else
527 rtc_timer_remove(rtc, &rtc->aie_timer);
528 }
529
530 if (err)
531 /* nothing */;
532 else if (!rtc->ops)
533 err = -ENODEV;
534 else if (!test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->alarm_irq_enable)
535 err = -EINVAL;
536 else
537 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
538
539 mutex_unlock(&rtc->ops_lock);
540
541 trace_rtc_alarm_irq_enable(enabled, err);
542 return err;
543}
544EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
545
546int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
547{
548 int err;
549
550 err = mutex_lock_interruptible(&rtc->ops_lock);
551 if (err)
552 return err;
553
554#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
555 if (enabled == 0 && rtc->uie_irq_active) {
556 mutex_unlock(&rtc->ops_lock);
557 return rtc_dev_update_irq_enable_emul(rtc, 0);
558 }
559#endif
560 /* make sure we're changing state */
561 if (rtc->uie_rtctimer.enabled == enabled)
562 goto out;
563
564 if (rtc->uie_unsupported || !test_bit(RTC_FEATURE_ALARM, rtc->features)) {
565 mutex_unlock(&rtc->ops_lock);
566#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
567 return rtc_dev_update_irq_enable_emul(rtc, enabled);
568#else
569 return -EINVAL;
570#endif
571 }
572
573 if (enabled) {
574 struct rtc_time tm;
575 ktime_t now, onesec;
576
577 err = __rtc_read_time(rtc, &tm);
578 if (err)
579 goto out;
580 onesec = ktime_set(1, 0);
581 now = rtc_tm_to_ktime(tm);
582 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
583 rtc->uie_rtctimer.period = ktime_set(1, 0);
584 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
585 } else {
586 rtc_timer_remove(rtc, &rtc->uie_rtctimer);
587 }
588
589out:
590 mutex_unlock(&rtc->ops_lock);
591
592 return err;
593}
594EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
595
596/**
597 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
598 * @rtc: pointer to the rtc device
599 * @num: number of occurence of the event
600 * @mode: type of the event, RTC_AF, RTC_UF of RTC_PF
601 *
602 * This function is called when an AIE, UIE or PIE mode interrupt
603 * has occurred (or been emulated).
604 *
605 */
606void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
607{
608 unsigned long flags;
609
610 /* mark one irq of the appropriate mode */
611 spin_lock_irqsave(&rtc->irq_lock, flags);
612 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF | mode);
613 spin_unlock_irqrestore(&rtc->irq_lock, flags);
614
615 wake_up_interruptible(&rtc->irq_queue);
616 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
617}
618
619/**
620 * rtc_aie_update_irq - AIE mode rtctimer hook
621 * @rtc: pointer to the rtc_device
622 *
623 * This functions is called when the aie_timer expires.
624 */
625void rtc_aie_update_irq(struct rtc_device *rtc)
626{
627 rtc_handle_legacy_irq(rtc, 1, RTC_AF);
628}
629
630/**
631 * rtc_uie_update_irq - UIE mode rtctimer hook
632 * @rtc: pointer to the rtc_device
633 *
634 * This functions is called when the uie_timer expires.
635 */
636void rtc_uie_update_irq(struct rtc_device *rtc)
637{
638 rtc_handle_legacy_irq(rtc, 1, RTC_UF);
639}
640
641/**
642 * rtc_pie_update_irq - PIE mode hrtimer hook
643 * @timer: pointer to the pie mode hrtimer
644 *
645 * This function is used to emulate PIE mode interrupts
646 * using an hrtimer. This function is called when the periodic
647 * hrtimer expires.
648 */
649enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
650{
651 struct rtc_device *rtc;
652 ktime_t period;
653 u64 count;
654
655 rtc = container_of(timer, struct rtc_device, pie_timer);
656
657 period = NSEC_PER_SEC / rtc->irq_freq;
658 count = hrtimer_forward_now(timer, period);
659
660 rtc_handle_legacy_irq(rtc, count, RTC_PF);
661
662 return HRTIMER_RESTART;
663}
664
665/**
666 * rtc_update_irq - Triggered when a RTC interrupt occurs.
667 * @rtc: the rtc device
668 * @num: how many irqs are being reported (usually one)
669 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
670 * Context: any
671 */
672void rtc_update_irq(struct rtc_device *rtc,
673 unsigned long num, unsigned long events)
674{
675 if (IS_ERR_OR_NULL(rtc))
676 return;
677
678 pm_stay_awake(rtc->dev.parent);
679 schedule_work(&rtc->irqwork);
680}
681EXPORT_SYMBOL_GPL(rtc_update_irq);
682
683struct rtc_device *rtc_class_open(const char *name)
684{
685 struct device *dev;
686 struct rtc_device *rtc = NULL;
687
688 dev = class_find_device_by_name(rtc_class, name);
689 if (dev)
690 rtc = to_rtc_device(dev);
691
692 if (rtc) {
693 if (!try_module_get(rtc->owner)) {
694 put_device(dev);
695 rtc = NULL;
696 }
697 }
698
699 return rtc;
700}
701EXPORT_SYMBOL_GPL(rtc_class_open);
702
703void rtc_class_close(struct rtc_device *rtc)
704{
705 module_put(rtc->owner);
706 put_device(&rtc->dev);
707}
708EXPORT_SYMBOL_GPL(rtc_class_close);
709
710static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
711{
712 /*
713 * We always cancel the timer here first, because otherwise
714 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
715 * when we manage to start the timer before the callback
716 * returns HRTIMER_RESTART.
717 *
718 * We cannot use hrtimer_cancel() here as a running callback
719 * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
720 * would spin forever.
721 */
722 if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
723 return -1;
724
725 if (enabled) {
726 ktime_t period = NSEC_PER_SEC / rtc->irq_freq;
727
728 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
729 }
730 return 0;
731}
732
733/**
734 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
735 * @rtc: the rtc device
736 * @enabled: true to enable periodic IRQs
737 * Context: any
738 *
739 * Note that rtc_irq_set_freq() should previously have been used to
740 * specify the desired frequency of periodic IRQ.
741 */
742int rtc_irq_set_state(struct rtc_device *rtc, int enabled)
743{
744 int err = 0;
745
746 while (rtc_update_hrtimer(rtc, enabled) < 0)
747 cpu_relax();
748
749 rtc->pie_enabled = enabled;
750
751 trace_rtc_irq_set_state(enabled, err);
752 return err;
753}
754
755/**
756 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
757 * @rtc: the rtc device
758 * @freq: positive frequency
759 * Context: any
760 *
761 * Note that rtc_irq_set_state() is used to enable or disable the
762 * periodic IRQs.
763 */
764int rtc_irq_set_freq(struct rtc_device *rtc, int freq)
765{
766 int err = 0;
767
768 if (freq <= 0 || freq > RTC_MAX_FREQ)
769 return -EINVAL;
770
771 rtc->irq_freq = freq;
772 while (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0)
773 cpu_relax();
774
775 trace_rtc_irq_set_freq(freq, err);
776 return err;
777}
778
779/**
780 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
781 * @rtc: rtc device
782 * @timer: timer being added.
783 *
784 * Enqueues a timer onto the rtc devices timerqueue and sets
785 * the next alarm event appropriately.
786 *
787 * Sets the enabled bit on the added timer.
788 *
789 * Must hold ops_lock for proper serialization of timerqueue
790 */
791static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
792{
793 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
794 struct rtc_time tm;
795 ktime_t now;
796
797 timer->enabled = 1;
798 __rtc_read_time(rtc, &tm);
799 now = rtc_tm_to_ktime(tm);
800
801 /* Skip over expired timers */
802 while (next) {
803 if (next->expires >= now)
804 break;
805 next = timerqueue_iterate_next(next);
806 }
807
808 timerqueue_add(&rtc->timerqueue, &timer->node);
809 trace_rtc_timer_enqueue(timer);
810 if (!next || ktime_before(timer->node.expires, next->expires)) {
811 struct rtc_wkalrm alarm;
812 int err;
813
814 alarm.time = rtc_ktime_to_tm(timer->node.expires);
815 alarm.enabled = 1;
816 err = __rtc_set_alarm(rtc, &alarm);
817 if (err == -ETIME) {
818 pm_stay_awake(rtc->dev.parent);
819 schedule_work(&rtc->irqwork);
820 } else if (err) {
821 timerqueue_del(&rtc->timerqueue, &timer->node);
822 trace_rtc_timer_dequeue(timer);
823 timer->enabled = 0;
824 return err;
825 }
826 }
827 return 0;
828}
829
830static void rtc_alarm_disable(struct rtc_device *rtc)
831{
832 if (!rtc->ops || !test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->alarm_irq_enable)
833 return;
834
835 rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
836 trace_rtc_alarm_irq_enable(0, 0);
837}
838
839/**
840 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
841 * @rtc: rtc device
842 * @timer: timer being removed.
843 *
844 * Removes a timer onto the rtc devices timerqueue and sets
845 * the next alarm event appropriately.
846 *
847 * Clears the enabled bit on the removed timer.
848 *
849 * Must hold ops_lock for proper serialization of timerqueue
850 */
851static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
852{
853 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
854
855 timerqueue_del(&rtc->timerqueue, &timer->node);
856 trace_rtc_timer_dequeue(timer);
857 timer->enabled = 0;
858 if (next == &timer->node) {
859 struct rtc_wkalrm alarm;
860 int err;
861
862 next = timerqueue_getnext(&rtc->timerqueue);
863 if (!next) {
864 rtc_alarm_disable(rtc);
865 return;
866 }
867 alarm.time = rtc_ktime_to_tm(next->expires);
868 alarm.enabled = 1;
869 err = __rtc_set_alarm(rtc, &alarm);
870 if (err == -ETIME) {
871 pm_stay_awake(rtc->dev.parent);
872 schedule_work(&rtc->irqwork);
873 }
874 }
875}
876
877/**
878 * rtc_timer_do_work - Expires rtc timers
879 * @work: work item
880 *
881 * Expires rtc timers. Reprograms next alarm event if needed.
882 * Called via worktask.
883 *
884 * Serializes access to timerqueue via ops_lock mutex
885 */
886void rtc_timer_do_work(struct work_struct *work)
887{
888 struct rtc_timer *timer;
889 struct timerqueue_node *next;
890 ktime_t now;
891 struct rtc_time tm;
892
893 struct rtc_device *rtc =
894 container_of(work, struct rtc_device, irqwork);
895
896 mutex_lock(&rtc->ops_lock);
897again:
898 __rtc_read_time(rtc, &tm);
899 now = rtc_tm_to_ktime(tm);
900 while ((next = timerqueue_getnext(&rtc->timerqueue))) {
901 if (next->expires > now)
902 break;
903
904 /* expire timer */
905 timer = container_of(next, struct rtc_timer, node);
906 timerqueue_del(&rtc->timerqueue, &timer->node);
907 trace_rtc_timer_dequeue(timer);
908 timer->enabled = 0;
909 if (timer->func)
910 timer->func(timer->rtc);
911
912 trace_rtc_timer_fired(timer);
913 /* Re-add/fwd periodic timers */
914 if (ktime_to_ns(timer->period)) {
915 timer->node.expires = ktime_add(timer->node.expires,
916 timer->period);
917 timer->enabled = 1;
918 timerqueue_add(&rtc->timerqueue, &timer->node);
919 trace_rtc_timer_enqueue(timer);
920 }
921 }
922
923 /* Set next alarm */
924 if (next) {
925 struct rtc_wkalrm alarm;
926 int err;
927 int retry = 3;
928
929 alarm.time = rtc_ktime_to_tm(next->expires);
930 alarm.enabled = 1;
931reprogram:
932 err = __rtc_set_alarm(rtc, &alarm);
933 if (err == -ETIME) {
934 goto again;
935 } else if (err) {
936 if (retry-- > 0)
937 goto reprogram;
938
939 timer = container_of(next, struct rtc_timer, node);
940 timerqueue_del(&rtc->timerqueue, &timer->node);
941 trace_rtc_timer_dequeue(timer);
942 timer->enabled = 0;
943 dev_err(&rtc->dev, "__rtc_set_alarm: err=%d\n", err);
944 goto again;
945 }
946 } else {
947 rtc_alarm_disable(rtc);
948 }
949
950 pm_relax(rtc->dev.parent);
951 mutex_unlock(&rtc->ops_lock);
952}
953
954/* rtc_timer_init - Initializes an rtc_timer
955 * @timer: timer to be intiialized
956 * @f: function pointer to be called when timer fires
957 * @rtc: pointer to the rtc_device
958 *
959 * Kernel interface to initializing an rtc_timer.
960 */
961void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
962 struct rtc_device *rtc)
963{
964 timerqueue_init(&timer->node);
965 timer->enabled = 0;
966 timer->func = f;
967 timer->rtc = rtc;
968}
969
970/* rtc_timer_start - Sets an rtc_timer to fire in the future
971 * @ rtc: rtc device to be used
972 * @ timer: timer being set
973 * @ expires: time at which to expire the timer
974 * @ period: period that the timer will recur
975 *
976 * Kernel interface to set an rtc_timer
977 */
978int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
979 ktime_t expires, ktime_t period)
980{
981 int ret = 0;
982
983 mutex_lock(&rtc->ops_lock);
984 if (timer->enabled)
985 rtc_timer_remove(rtc, timer);
986
987 timer->node.expires = expires;
988 timer->period = period;
989
990 ret = rtc_timer_enqueue(rtc, timer);
991
992 mutex_unlock(&rtc->ops_lock);
993 return ret;
994}
995
996/* rtc_timer_cancel - Stops an rtc_timer
997 * @ rtc: rtc device to be used
998 * @ timer: timer being set
999 *
1000 * Kernel interface to cancel an rtc_timer
1001 */
1002void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
1003{
1004 mutex_lock(&rtc->ops_lock);
1005 if (timer->enabled)
1006 rtc_timer_remove(rtc, timer);
1007 mutex_unlock(&rtc->ops_lock);
1008}
1009
1010/**
1011 * rtc_read_offset - Read the amount of rtc offset in parts per billion
1012 * @rtc: rtc device to be used
1013 * @offset: the offset in parts per billion
1014 *
1015 * see below for details.
1016 *
1017 * Kernel interface to read rtc clock offset
1018 * Returns 0 on success, or a negative number on error.
1019 * If read_offset() is not implemented for the rtc, return -EINVAL
1020 */
1021int rtc_read_offset(struct rtc_device *rtc, long *offset)
1022{
1023 int ret;
1024
1025 if (!rtc->ops)
1026 return -ENODEV;
1027
1028 if (!rtc->ops->read_offset)
1029 return -EINVAL;
1030
1031 mutex_lock(&rtc->ops_lock);
1032 ret = rtc->ops->read_offset(rtc->dev.parent, offset);
1033 mutex_unlock(&rtc->ops_lock);
1034
1035 trace_rtc_read_offset(*offset, ret);
1036 return ret;
1037}
1038
1039/**
1040 * rtc_set_offset - Adjusts the duration of the average second
1041 * @rtc: rtc device to be used
1042 * @offset: the offset in parts per billion
1043 *
1044 * Some rtc's allow an adjustment to the average duration of a second
1045 * to compensate for differences in the actual clock rate due to temperature,
1046 * the crystal, capacitor, etc.
1047 *
1048 * The adjustment applied is as follows:
1049 * t = t0 * (1 + offset * 1e-9)
1050 * where t0 is the measured length of 1 RTC second with offset = 0
1051 *
1052 * Kernel interface to adjust an rtc clock offset.
1053 * Return 0 on success, or a negative number on error.
1054 * If the rtc offset is not setable (or not implemented), return -EINVAL
1055 */
1056int rtc_set_offset(struct rtc_device *rtc, long offset)
1057{
1058 int ret;
1059
1060 if (!rtc->ops)
1061 return -ENODEV;
1062
1063 if (!rtc->ops->set_offset)
1064 return -EINVAL;
1065
1066 mutex_lock(&rtc->ops_lock);
1067 ret = rtc->ops->set_offset(rtc->dev.parent, offset);
1068 mutex_unlock(&rtc->ops_lock);
1069
1070 trace_rtc_set_offset(offset, ret);
1071 return ret;
1072}