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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 <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 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 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 err = rtc_valid_tm(&alarm->time);
278 if (!err)
279 goto done;
280
281 /* get the "after" timestamp, to detect wrapped fields */
282 err = rtc_read_time(rtc, &now);
283 if (err < 0)
284 return err;
285
286 /* note that tm_sec is a "don't care" value here: */
287 } while (before.tm_min != now.tm_min ||
288 before.tm_hour != now.tm_hour ||
289 before.tm_mon != now.tm_mon ||
290 before.tm_year != now.tm_year);
291
292 /* Fill in the missing alarm fields using the timestamp; we
293 * know there's at least one since alarm->time is invalid.
294 */
295 if (alarm->time.tm_sec == -1)
296 alarm->time.tm_sec = now.tm_sec;
297 if (alarm->time.tm_min == -1)
298 alarm->time.tm_min = now.tm_min;
299 if (alarm->time.tm_hour == -1)
300 alarm->time.tm_hour = now.tm_hour;
301
302 /* For simplicity, only support date rollover for now */
303 if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) {
304 alarm->time.tm_mday = now.tm_mday;
305 missing = day;
306 }
307 if ((unsigned int)alarm->time.tm_mon >= 12) {
308 alarm->time.tm_mon = now.tm_mon;
309 if (missing == none)
310 missing = month;
311 }
312 if (alarm->time.tm_year == -1) {
313 alarm->time.tm_year = now.tm_year;
314 if (missing == none)
315 missing = year;
316 }
317
318 /* Can't proceed if alarm is still invalid after replacing
319 * missing fields.
320 */
321 err = rtc_valid_tm(&alarm->time);
322 if (err)
323 goto done;
324
325 /* with luck, no rollover is needed */
326 t_now = rtc_tm_to_time64(&now);
327 t_alm = rtc_tm_to_time64(&alarm->time);
328 if (t_now < t_alm)
329 goto done;
330
331 switch (missing) {
332 /* 24 hour rollover ... if it's now 10am Monday, an alarm that
333 * that will trigger at 5am will do so at 5am Tuesday, which
334 * could also be in the next month or year. This is a common
335 * case, especially for PCs.
336 */
337 case day:
338 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
339 t_alm += 24 * 60 * 60;
340 rtc_time64_to_tm(t_alm, &alarm->time);
341 break;
342
343 /* Month rollover ... if it's the 31th, an alarm on the 3rd will
344 * be next month. An alarm matching on the 30th, 29th, or 28th
345 * may end up in the month after that! Many newer PCs support
346 * this type of alarm.
347 */
348 case month:
349 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
350 do {
351 if (alarm->time.tm_mon < 11) {
352 alarm->time.tm_mon++;
353 } else {
354 alarm->time.tm_mon = 0;
355 alarm->time.tm_year++;
356 }
357 days = rtc_month_days(alarm->time.tm_mon,
358 alarm->time.tm_year);
359 } while (days < alarm->time.tm_mday);
360 break;
361
362 /* Year rollover ... easy except for leap years! */
363 case year:
364 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
365 do {
366 alarm->time.tm_year++;
367 } while (!is_leap_year(alarm->time.tm_year + 1900) &&
368 rtc_valid_tm(&alarm->time) != 0);
369 break;
370
371 default:
372 dev_warn(&rtc->dev, "alarm rollover not handled\n");
373 }
374
375 err = rtc_valid_tm(&alarm->time);
376
377done:
378 if (err && alarm->enabled)
379 dev_warn(&rtc->dev, "invalid alarm value: %ptR\n",
380 &alarm->time);
381 else
382 rtc_add_offset(rtc, &alarm->time);
383
384 return err;
385}
386
387int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
388{
389 int err;
390
391 err = mutex_lock_interruptible(&rtc->ops_lock);
392 if (err)
393 return err;
394 if (!rtc->ops) {
395 err = -ENODEV;
396 } else if (!test_bit(RTC_FEATURE_ALARM, rtc->features)) {
397 err = -EINVAL;
398 } else {
399 memset(alarm, 0, sizeof(struct rtc_wkalrm));
400 alarm->enabled = rtc->aie_timer.enabled;
401 alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
402 }
403 mutex_unlock(&rtc->ops_lock);
404
405 trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
406 return err;
407}
408EXPORT_SYMBOL_GPL(rtc_read_alarm);
409
410static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
411{
412 struct rtc_time tm;
413 time64_t now, scheduled;
414 int err;
415
416 err = rtc_valid_tm(&alarm->time);
417 if (err)
418 return err;
419
420 scheduled = rtc_tm_to_time64(&alarm->time);
421
422 /* Make sure we're not setting alarms in the past */
423 err = __rtc_read_time(rtc, &tm);
424 if (err)
425 return err;
426 now = rtc_tm_to_time64(&tm);
427
428 if (scheduled <= now)
429 return -ETIME;
430 /*
431 * XXX - We just checked to make sure the alarm time is not
432 * in the past, but there is still a race window where if
433 * the is alarm set for the next second and the second ticks
434 * over right here, before we set the alarm.
435 */
436
437 rtc_subtract_offset(rtc, &alarm->time);
438
439 if (!rtc->ops)
440 err = -ENODEV;
441 else if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
442 err = -EINVAL;
443 else
444 err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
445
446 trace_rtc_set_alarm(rtc_tm_to_time64(&alarm->time), err);
447 return err;
448}
449
450int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
451{
452 ktime_t alarm_time;
453 int err;
454
455 if (!rtc->ops)
456 return -ENODEV;
457 else if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
458 return -EINVAL;
459
460 err = rtc_valid_tm(&alarm->time);
461 if (err != 0)
462 return err;
463
464 err = rtc_valid_range(rtc, &alarm->time);
465 if (err)
466 return err;
467
468 err = mutex_lock_interruptible(&rtc->ops_lock);
469 if (err)
470 return err;
471 if (rtc->aie_timer.enabled)
472 rtc_timer_remove(rtc, &rtc->aie_timer);
473
474 alarm_time = rtc_tm_to_ktime(alarm->time);
475 /*
476 * Round down so we never miss a deadline, checking for past deadline is
477 * done in __rtc_set_alarm
478 */
479 if (test_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features))
480 alarm_time = ktime_sub_ns(alarm_time, (u64)alarm->time.tm_sec * NSEC_PER_SEC);
481
482 rtc->aie_timer.node.expires = alarm_time;
483 rtc->aie_timer.period = 0;
484 if (alarm->enabled)
485 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
486
487 mutex_unlock(&rtc->ops_lock);
488
489 return err;
490}
491EXPORT_SYMBOL_GPL(rtc_set_alarm);
492
493/* Called once per device from rtc_device_register */
494int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
495{
496 int err;
497 struct rtc_time now;
498
499 err = rtc_valid_tm(&alarm->time);
500 if (err != 0)
501 return err;
502
503 err = rtc_read_time(rtc, &now);
504 if (err)
505 return err;
506
507 err = mutex_lock_interruptible(&rtc->ops_lock);
508 if (err)
509 return err;
510
511 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
512 rtc->aie_timer.period = 0;
513
514 /* Alarm has to be enabled & in the future for us to enqueue it */
515 if (alarm->enabled && (rtc_tm_to_ktime(now) <
516 rtc->aie_timer.node.expires)) {
517 rtc->aie_timer.enabled = 1;
518 timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
519 trace_rtc_timer_enqueue(&rtc->aie_timer);
520 }
521 mutex_unlock(&rtc->ops_lock);
522 return err;
523}
524EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
525
526int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
527{
528 int err;
529
530 err = mutex_lock_interruptible(&rtc->ops_lock);
531 if (err)
532 return err;
533
534 if (rtc->aie_timer.enabled != enabled) {
535 if (enabled)
536 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
537 else
538 rtc_timer_remove(rtc, &rtc->aie_timer);
539 }
540
541 if (err)
542 /* nothing */;
543 else if (!rtc->ops)
544 err = -ENODEV;
545 else if (!test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->alarm_irq_enable)
546 err = -EINVAL;
547 else
548 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
549
550 mutex_unlock(&rtc->ops_lock);
551
552 trace_rtc_alarm_irq_enable(enabled, err);
553 return err;
554}
555EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
556
557int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
558{
559 int err;
560
561 err = mutex_lock_interruptible(&rtc->ops_lock);
562 if (err)
563 return err;
564
565#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
566 if (enabled == 0 && rtc->uie_irq_active) {
567 mutex_unlock(&rtc->ops_lock);
568 return rtc_dev_update_irq_enable_emul(rtc, 0);
569 }
570#endif
571 /* make sure we're changing state */
572 if (rtc->uie_rtctimer.enabled == enabled)
573 goto out;
574
575 if (!test_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features) ||
576 !test_bit(RTC_FEATURE_ALARM, rtc->features)) {
577 mutex_unlock(&rtc->ops_lock);
578#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
579 return rtc_dev_update_irq_enable_emul(rtc, enabled);
580#else
581 return -EINVAL;
582#endif
583 }
584
585 if (enabled) {
586 struct rtc_time tm;
587 ktime_t now, onesec;
588
589 err = __rtc_read_time(rtc, &tm);
590 if (err)
591 goto out;
592 onesec = ktime_set(1, 0);
593 now = rtc_tm_to_ktime(tm);
594 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
595 rtc->uie_rtctimer.period = ktime_set(1, 0);
596 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
597 } else {
598 rtc_timer_remove(rtc, &rtc->uie_rtctimer);
599 }
600
601out:
602 mutex_unlock(&rtc->ops_lock);
603
604 return err;
605}
606EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
607
608/**
609 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
610 * @rtc: pointer to the rtc device
611 * @num: number of occurence of the event
612 * @mode: type of the event, RTC_AF, RTC_UF of RTC_PF
613 *
614 * This function is called when an AIE, UIE or PIE mode interrupt
615 * has occurred (or been emulated).
616 *
617 */
618void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
619{
620 unsigned long flags;
621
622 /* mark one irq of the appropriate mode */
623 spin_lock_irqsave(&rtc->irq_lock, flags);
624 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF | mode);
625 spin_unlock_irqrestore(&rtc->irq_lock, flags);
626
627 wake_up_interruptible(&rtc->irq_queue);
628 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
629}
630
631/**
632 * rtc_aie_update_irq - AIE mode rtctimer hook
633 * @rtc: pointer to the rtc_device
634 *
635 * This functions is called when the aie_timer expires.
636 */
637void rtc_aie_update_irq(struct rtc_device *rtc)
638{
639 rtc_handle_legacy_irq(rtc, 1, RTC_AF);
640}
641
642/**
643 * rtc_uie_update_irq - UIE mode rtctimer hook
644 * @rtc: pointer to the rtc_device
645 *
646 * This functions is called when the uie_timer expires.
647 */
648void rtc_uie_update_irq(struct rtc_device *rtc)
649{
650 rtc_handle_legacy_irq(rtc, 1, RTC_UF);
651}
652
653/**
654 * rtc_pie_update_irq - PIE mode hrtimer hook
655 * @timer: pointer to the pie mode hrtimer
656 *
657 * This function is used to emulate PIE mode interrupts
658 * using an hrtimer. This function is called when the periodic
659 * hrtimer expires.
660 */
661enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
662{
663 struct rtc_device *rtc;
664 ktime_t period;
665 u64 count;
666
667 rtc = container_of(timer, struct rtc_device, pie_timer);
668
669 period = NSEC_PER_SEC / rtc->irq_freq;
670 count = hrtimer_forward_now(timer, period);
671
672 rtc_handle_legacy_irq(rtc, count, RTC_PF);
673
674 return HRTIMER_RESTART;
675}
676
677/**
678 * rtc_update_irq - Triggered when a RTC interrupt occurs.
679 * @rtc: the rtc device
680 * @num: how many irqs are being reported (usually one)
681 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
682 * Context: any
683 */
684void rtc_update_irq(struct rtc_device *rtc,
685 unsigned long num, unsigned long events)
686{
687 if (IS_ERR_OR_NULL(rtc))
688 return;
689
690 pm_stay_awake(rtc->dev.parent);
691 schedule_work(&rtc->irqwork);
692}
693EXPORT_SYMBOL_GPL(rtc_update_irq);
694
695struct rtc_device *rtc_class_open(const char *name)
696{
697 struct device *dev;
698 struct rtc_device *rtc = NULL;
699
700 dev = class_find_device_by_name(&rtc_class, name);
701 if (dev)
702 rtc = to_rtc_device(dev);
703
704 if (rtc) {
705 if (!try_module_get(rtc->owner)) {
706 put_device(dev);
707 rtc = NULL;
708 }
709 }
710
711 return rtc;
712}
713EXPORT_SYMBOL_GPL(rtc_class_open);
714
715void rtc_class_close(struct rtc_device *rtc)
716{
717 module_put(rtc->owner);
718 put_device(&rtc->dev);
719}
720EXPORT_SYMBOL_GPL(rtc_class_close);
721
722static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
723{
724 /*
725 * We always cancel the timer here first, because otherwise
726 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
727 * when we manage to start the timer before the callback
728 * returns HRTIMER_RESTART.
729 *
730 * We cannot use hrtimer_cancel() here as a running callback
731 * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
732 * would spin forever.
733 */
734 if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
735 return -1;
736
737 if (enabled) {
738 ktime_t period = NSEC_PER_SEC / rtc->irq_freq;
739
740 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
741 }
742 return 0;
743}
744
745/**
746 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
747 * @rtc: the rtc device
748 * @enabled: true to enable periodic IRQs
749 * Context: any
750 *
751 * Note that rtc_irq_set_freq() should previously have been used to
752 * specify the desired frequency of periodic IRQ.
753 */
754int rtc_irq_set_state(struct rtc_device *rtc, int enabled)
755{
756 int err = 0;
757
758 while (rtc_update_hrtimer(rtc, enabled) < 0)
759 cpu_relax();
760
761 rtc->pie_enabled = enabled;
762
763 trace_rtc_irq_set_state(enabled, err);
764 return err;
765}
766
767/**
768 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
769 * @rtc: the rtc device
770 * @freq: positive frequency
771 * Context: any
772 *
773 * Note that rtc_irq_set_state() is used to enable or disable the
774 * periodic IRQs.
775 */
776int rtc_irq_set_freq(struct rtc_device *rtc, int freq)
777{
778 int err = 0;
779
780 if (freq <= 0 || freq > RTC_MAX_FREQ)
781 return -EINVAL;
782
783 rtc->irq_freq = freq;
784 while (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0)
785 cpu_relax();
786
787 trace_rtc_irq_set_freq(freq, err);
788 return err;
789}
790
791/**
792 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
793 * @rtc: rtc device
794 * @timer: timer being added.
795 *
796 * Enqueues a timer onto the rtc devices timerqueue and sets
797 * the next alarm event appropriately.
798 *
799 * Sets the enabled bit on the added timer.
800 *
801 * Must hold ops_lock for proper serialization of timerqueue
802 */
803static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
804{
805 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
806 struct rtc_time tm;
807 ktime_t now;
808 int err;
809
810 err = __rtc_read_time(rtc, &tm);
811 if (err)
812 return err;
813
814 timer->enabled = 1;
815 now = rtc_tm_to_ktime(tm);
816
817 /* Skip over expired timers */
818 while (next) {
819 if (next->expires >= now)
820 break;
821 next = timerqueue_iterate_next(next);
822 }
823
824 timerqueue_add(&rtc->timerqueue, &timer->node);
825 trace_rtc_timer_enqueue(timer);
826 if (!next || ktime_before(timer->node.expires, next->expires)) {
827 struct rtc_wkalrm alarm;
828
829 alarm.time = rtc_ktime_to_tm(timer->node.expires);
830 alarm.enabled = 1;
831 err = __rtc_set_alarm(rtc, &alarm);
832 if (err == -ETIME) {
833 pm_stay_awake(rtc->dev.parent);
834 schedule_work(&rtc->irqwork);
835 } else if (err) {
836 timerqueue_del(&rtc->timerqueue, &timer->node);
837 trace_rtc_timer_dequeue(timer);
838 timer->enabled = 0;
839 return err;
840 }
841 }
842 return 0;
843}
844
845static void rtc_alarm_disable(struct rtc_device *rtc)
846{
847 if (!rtc->ops || !test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->alarm_irq_enable)
848 return;
849
850 rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
851 trace_rtc_alarm_irq_enable(0, 0);
852}
853
854/**
855 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
856 * @rtc: rtc device
857 * @timer: timer being removed.
858 *
859 * Removes a timer onto the rtc devices timerqueue and sets
860 * the next alarm event appropriately.
861 *
862 * Clears the enabled bit on the removed timer.
863 *
864 * Must hold ops_lock for proper serialization of timerqueue
865 */
866static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
867{
868 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
869
870 timerqueue_del(&rtc->timerqueue, &timer->node);
871 trace_rtc_timer_dequeue(timer);
872 timer->enabled = 0;
873 if (next == &timer->node) {
874 struct rtc_wkalrm alarm;
875 int err;
876
877 next = timerqueue_getnext(&rtc->timerqueue);
878 if (!next) {
879 rtc_alarm_disable(rtc);
880 return;
881 }
882 alarm.time = rtc_ktime_to_tm(next->expires);
883 alarm.enabled = 1;
884 err = __rtc_set_alarm(rtc, &alarm);
885 if (err == -ETIME) {
886 pm_stay_awake(rtc->dev.parent);
887 schedule_work(&rtc->irqwork);
888 }
889 }
890}
891
892/**
893 * rtc_timer_do_work - Expires rtc timers
894 * @work: work item
895 *
896 * Expires rtc timers. Reprograms next alarm event if needed.
897 * Called via worktask.
898 *
899 * Serializes access to timerqueue via ops_lock mutex
900 */
901void rtc_timer_do_work(struct work_struct *work)
902{
903 struct rtc_timer *timer;
904 struct timerqueue_node *next;
905 ktime_t now;
906 struct rtc_time tm;
907 int err;
908
909 struct rtc_device *rtc =
910 container_of(work, struct rtc_device, irqwork);
911
912 mutex_lock(&rtc->ops_lock);
913again:
914 err = __rtc_read_time(rtc, &tm);
915 if (err) {
916 mutex_unlock(&rtc->ops_lock);
917 return;
918 }
919 now = rtc_tm_to_ktime(tm);
920 while ((next = timerqueue_getnext(&rtc->timerqueue))) {
921 if (next->expires > now)
922 break;
923
924 /* expire timer */
925 timer = container_of(next, struct rtc_timer, node);
926 timerqueue_del(&rtc->timerqueue, &timer->node);
927 trace_rtc_timer_dequeue(timer);
928 timer->enabled = 0;
929 if (timer->func)
930 timer->func(timer->rtc);
931
932 trace_rtc_timer_fired(timer);
933 /* Re-add/fwd periodic timers */
934 if (ktime_to_ns(timer->period)) {
935 timer->node.expires = ktime_add(timer->node.expires,
936 timer->period);
937 timer->enabled = 1;
938 timerqueue_add(&rtc->timerqueue, &timer->node);
939 trace_rtc_timer_enqueue(timer);
940 }
941 }
942
943 /* Set next alarm */
944 if (next) {
945 struct rtc_wkalrm alarm;
946 int err;
947 int retry = 3;
948
949 alarm.time = rtc_ktime_to_tm(next->expires);
950 alarm.enabled = 1;
951reprogram:
952 err = __rtc_set_alarm(rtc, &alarm);
953 if (err == -ETIME) {
954 goto again;
955 } else if (err) {
956 if (retry-- > 0)
957 goto reprogram;
958
959 timer = container_of(next, struct rtc_timer, node);
960 timerqueue_del(&rtc->timerqueue, &timer->node);
961 trace_rtc_timer_dequeue(timer);
962 timer->enabled = 0;
963 dev_err(&rtc->dev, "__rtc_set_alarm: err=%d\n", err);
964 goto again;
965 }
966 } else {
967 rtc_alarm_disable(rtc);
968 }
969
970 pm_relax(rtc->dev.parent);
971 mutex_unlock(&rtc->ops_lock);
972}
973
974/* rtc_timer_init - Initializes an rtc_timer
975 * @timer: timer to be intiialized
976 * @f: function pointer to be called when timer fires
977 * @rtc: pointer to the rtc_device
978 *
979 * Kernel interface to initializing an rtc_timer.
980 */
981void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
982 struct rtc_device *rtc)
983{
984 timerqueue_init(&timer->node);
985 timer->enabled = 0;
986 timer->func = f;
987 timer->rtc = rtc;
988}
989
990/* rtc_timer_start - Sets an rtc_timer to fire in the future
991 * @ rtc: rtc device to be used
992 * @ timer: timer being set
993 * @ expires: time at which to expire the timer
994 * @ period: period that the timer will recur
995 *
996 * Kernel interface to set an rtc_timer
997 */
998int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
999 ktime_t expires, ktime_t period)
1000{
1001 int ret = 0;
1002
1003 mutex_lock(&rtc->ops_lock);
1004 if (timer->enabled)
1005 rtc_timer_remove(rtc, timer);
1006
1007 timer->node.expires = expires;
1008 timer->period = period;
1009
1010 ret = rtc_timer_enqueue(rtc, timer);
1011
1012 mutex_unlock(&rtc->ops_lock);
1013 return ret;
1014}
1015
1016/* rtc_timer_cancel - Stops an rtc_timer
1017 * @ rtc: rtc device to be used
1018 * @ timer: timer being set
1019 *
1020 * Kernel interface to cancel an rtc_timer
1021 */
1022void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
1023{
1024 mutex_lock(&rtc->ops_lock);
1025 if (timer->enabled)
1026 rtc_timer_remove(rtc, timer);
1027 mutex_unlock(&rtc->ops_lock);
1028}
1029
1030/**
1031 * rtc_read_offset - Read the amount of rtc offset in parts per billion
1032 * @rtc: rtc device to be used
1033 * @offset: the offset in parts per billion
1034 *
1035 * see below for details.
1036 *
1037 * Kernel interface to read rtc clock offset
1038 * Returns 0 on success, or a negative number on error.
1039 * If read_offset() is not implemented for the rtc, return -EINVAL
1040 */
1041int rtc_read_offset(struct rtc_device *rtc, long *offset)
1042{
1043 int ret;
1044
1045 if (!rtc->ops)
1046 return -ENODEV;
1047
1048 if (!rtc->ops->read_offset)
1049 return -EINVAL;
1050
1051 mutex_lock(&rtc->ops_lock);
1052 ret = rtc->ops->read_offset(rtc->dev.parent, offset);
1053 mutex_unlock(&rtc->ops_lock);
1054
1055 trace_rtc_read_offset(*offset, ret);
1056 return ret;
1057}
1058
1059/**
1060 * rtc_set_offset - Adjusts the duration of the average second
1061 * @rtc: rtc device to be used
1062 * @offset: the offset in parts per billion
1063 *
1064 * Some rtc's allow an adjustment to the average duration of a second
1065 * to compensate for differences in the actual clock rate due to temperature,
1066 * the crystal, capacitor, etc.
1067 *
1068 * The adjustment applied is as follows:
1069 * t = t0 * (1 + offset * 1e-9)
1070 * where t0 is the measured length of 1 RTC second with offset = 0
1071 *
1072 * Kernel interface to adjust an rtc clock offset.
1073 * Return 0 on success, or a negative number on error.
1074 * If the rtc offset is not setable (or not implemented), return -EINVAL
1075 */
1076int rtc_set_offset(struct rtc_device *rtc, long offset)
1077{
1078 int ret;
1079
1080 if (!rtc->ops)
1081 return -ENODEV;
1082
1083 if (!rtc->ops->set_offset)
1084 return -EINVAL;
1085
1086 mutex_lock(&rtc->ops_lock);
1087 ret = rtc->ops->set_offset(rtc->dev.parent, offset);
1088 mutex_unlock(&rtc->ops_lock);
1089
1090 trace_rtc_set_offset(offset, ret);
1091 return ret;
1092}
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/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 }
34 return err;
35}
36
37int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
38{
39 int err;
40
41 err = mutex_lock_interruptible(&rtc->ops_lock);
42 if (err)
43 return err;
44
45 err = __rtc_read_time(rtc, tm);
46 mutex_unlock(&rtc->ops_lock);
47 return err;
48}
49EXPORT_SYMBOL_GPL(rtc_read_time);
50
51int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
52{
53 int err;
54
55 err = rtc_valid_tm(tm);
56 if (err != 0)
57 return err;
58
59 err = mutex_lock_interruptible(&rtc->ops_lock);
60 if (err)
61 return err;
62
63 if (!rtc->ops)
64 err = -ENODEV;
65 else if (rtc->ops->set_time)
66 err = rtc->ops->set_time(rtc->dev.parent, tm);
67 else if (rtc->ops->set_mmss) {
68 unsigned long secs;
69 err = rtc_tm_to_time(tm, &secs);
70 if (err == 0)
71 err = rtc->ops->set_mmss(rtc->dev.parent, secs);
72 } else
73 err = -EINVAL;
74
75 pm_stay_awake(rtc->dev.parent);
76 mutex_unlock(&rtc->ops_lock);
77 /* A timer might have just expired */
78 schedule_work(&rtc->irqwork);
79 return err;
80}
81EXPORT_SYMBOL_GPL(rtc_set_time);
82
83int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs)
84{
85 int err;
86
87 err = mutex_lock_interruptible(&rtc->ops_lock);
88 if (err)
89 return err;
90
91 if (!rtc->ops)
92 err = -ENODEV;
93 else if (rtc->ops->set_mmss)
94 err = rtc->ops->set_mmss(rtc->dev.parent, secs);
95 else if (rtc->ops->read_time && rtc->ops->set_time) {
96 struct rtc_time new, old;
97
98 err = rtc->ops->read_time(rtc->dev.parent, &old);
99 if (err == 0) {
100 rtc_time_to_tm(secs, &new);
101
102 /*
103 * avoid writing when we're going to change the day of
104 * the month. We will retry in the next minute. This
105 * basically means that if the RTC must not drift
106 * by more than 1 minute in 11 minutes.
107 */
108 if (!((old.tm_hour == 23 && old.tm_min == 59) ||
109 (new.tm_hour == 23 && new.tm_min == 59)))
110 err = rtc->ops->set_time(rtc->dev.parent,
111 &new);
112 }
113 } else {
114 err = -EINVAL;
115 }
116
117 pm_stay_awake(rtc->dev.parent);
118 mutex_unlock(&rtc->ops_lock);
119 /* A timer might have just expired */
120 schedule_work(&rtc->irqwork);
121
122 return err;
123}
124EXPORT_SYMBOL_GPL(rtc_set_mmss);
125
126static int rtc_read_alarm_internal(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
127{
128 int err;
129
130 err = mutex_lock_interruptible(&rtc->ops_lock);
131 if (err)
132 return err;
133
134 if (rtc->ops == NULL)
135 err = -ENODEV;
136 else if (!rtc->ops->read_alarm)
137 err = -EINVAL;
138 else {
139 memset(alarm, 0, sizeof(struct rtc_wkalrm));
140 err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
141 }
142
143 mutex_unlock(&rtc->ops_lock);
144 return err;
145}
146
147int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
148{
149 int err;
150 struct rtc_time before, now;
151 int first_time = 1;
152 unsigned long t_now, t_alm;
153 enum { none, day, month, year } missing = none;
154 unsigned days;
155
156 /* The lower level RTC driver may return -1 in some fields,
157 * creating invalid alarm->time values, for reasons like:
158 *
159 * - The hardware may not be capable of filling them in;
160 * many alarms match only on time-of-day fields, not
161 * day/month/year calendar data.
162 *
163 * - Some hardware uses illegal values as "wildcard" match
164 * values, which non-Linux firmware (like a BIOS) may try
165 * to set up as e.g. "alarm 15 minutes after each hour".
166 * Linux uses only oneshot alarms.
167 *
168 * When we see that here, we deal with it by using values from
169 * a current RTC timestamp for any missing (-1) values. The
170 * RTC driver prevents "periodic alarm" modes.
171 *
172 * But this can be racey, because some fields of the RTC timestamp
173 * may have wrapped in the interval since we read the RTC alarm,
174 * which would lead to us inserting inconsistent values in place
175 * of the -1 fields.
176 *
177 * Reading the alarm and timestamp in the reverse sequence
178 * would have the same race condition, and not solve the issue.
179 *
180 * So, we must first read the RTC timestamp,
181 * then read the RTC alarm value,
182 * and then read a second RTC timestamp.
183 *
184 * If any fields of the second timestamp have changed
185 * when compared with the first timestamp, then we know
186 * our timestamp may be inconsistent with that used by
187 * the low-level rtc_read_alarm_internal() function.
188 *
189 * So, when the two timestamps disagree, we just loop and do
190 * the process again to get a fully consistent set of values.
191 *
192 * This could all instead be done in the lower level driver,
193 * but since more than one lower level RTC implementation needs it,
194 * then it's probably best best to do it here instead of there..
195 */
196
197 /* Get the "before" timestamp */
198 err = rtc_read_time(rtc, &before);
199 if (err < 0)
200 return err;
201 do {
202 if (!first_time)
203 memcpy(&before, &now, sizeof(struct rtc_time));
204 first_time = 0;
205
206 /* get the RTC alarm values, which may be incomplete */
207 err = rtc_read_alarm_internal(rtc, alarm);
208 if (err)
209 return err;
210
211 /* full-function RTCs won't have such missing fields */
212 if (rtc_valid_tm(&alarm->time) == 0)
213 return 0;
214
215 /* get the "after" timestamp, to detect wrapped fields */
216 err = rtc_read_time(rtc, &now);
217 if (err < 0)
218 return err;
219
220 /* note that tm_sec is a "don't care" value here: */
221 } while ( before.tm_min != now.tm_min
222 || before.tm_hour != now.tm_hour
223 || before.tm_mon != now.tm_mon
224 || before.tm_year != now.tm_year);
225
226 /* Fill in the missing alarm fields using the timestamp; we
227 * know there's at least one since alarm->time is invalid.
228 */
229 if (alarm->time.tm_sec == -1)
230 alarm->time.tm_sec = now.tm_sec;
231 if (alarm->time.tm_min == -1)
232 alarm->time.tm_min = now.tm_min;
233 if (alarm->time.tm_hour == -1)
234 alarm->time.tm_hour = now.tm_hour;
235
236 /* For simplicity, only support date rollover for now */
237 if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) {
238 alarm->time.tm_mday = now.tm_mday;
239 missing = day;
240 }
241 if ((unsigned)alarm->time.tm_mon >= 12) {
242 alarm->time.tm_mon = now.tm_mon;
243 if (missing == none)
244 missing = month;
245 }
246 if (alarm->time.tm_year == -1) {
247 alarm->time.tm_year = now.tm_year;
248 if (missing == none)
249 missing = year;
250 }
251
252 /* with luck, no rollover is needed */
253 rtc_tm_to_time(&now, &t_now);
254 rtc_tm_to_time(&alarm->time, &t_alm);
255 if (t_now < t_alm)
256 goto done;
257
258 switch (missing) {
259
260 /* 24 hour rollover ... if it's now 10am Monday, an alarm that
261 * that will trigger at 5am will do so at 5am Tuesday, which
262 * could also be in the next month or year. This is a common
263 * case, especially for PCs.
264 */
265 case day:
266 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
267 t_alm += 24 * 60 * 60;
268 rtc_time_to_tm(t_alm, &alarm->time);
269 break;
270
271 /* Month rollover ... if it's the 31th, an alarm on the 3rd will
272 * be next month. An alarm matching on the 30th, 29th, or 28th
273 * may end up in the month after that! Many newer PCs support
274 * this type of alarm.
275 */
276 case month:
277 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
278 do {
279 if (alarm->time.tm_mon < 11)
280 alarm->time.tm_mon++;
281 else {
282 alarm->time.tm_mon = 0;
283 alarm->time.tm_year++;
284 }
285 days = rtc_month_days(alarm->time.tm_mon,
286 alarm->time.tm_year);
287 } while (days < alarm->time.tm_mday);
288 break;
289
290 /* Year rollover ... easy except for leap years! */
291 case year:
292 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
293 do {
294 alarm->time.tm_year++;
295 } while (rtc_valid_tm(&alarm->time) != 0);
296 break;
297
298 default:
299 dev_warn(&rtc->dev, "alarm rollover not handled\n");
300 }
301
302done:
303 return 0;
304}
305
306int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
307{
308 int err;
309
310 err = mutex_lock_interruptible(&rtc->ops_lock);
311 if (err)
312 return err;
313 if (rtc->ops == NULL)
314 err = -ENODEV;
315 else if (!rtc->ops->read_alarm)
316 err = -EINVAL;
317 else {
318 memset(alarm, 0, sizeof(struct rtc_wkalrm));
319 alarm->enabled = rtc->aie_timer.enabled;
320 alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
321 }
322 mutex_unlock(&rtc->ops_lock);
323
324 return err;
325}
326EXPORT_SYMBOL_GPL(rtc_read_alarm);
327
328static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
329{
330 struct rtc_time tm;
331 long now, scheduled;
332 int err;
333
334 err = rtc_valid_tm(&alarm->time);
335 if (err)
336 return err;
337 rtc_tm_to_time(&alarm->time, &scheduled);
338
339 /* Make sure we're not setting alarms in the past */
340 err = __rtc_read_time(rtc, &tm);
341 rtc_tm_to_time(&tm, &now);
342 if (scheduled <= now)
343 return -ETIME;
344 /*
345 * XXX - We just checked to make sure the alarm time is not
346 * in the past, but there is still a race window where if
347 * the is alarm set for the next second and the second ticks
348 * over right here, before we set the alarm.
349 */
350
351 if (!rtc->ops)
352 err = -ENODEV;
353 else if (!rtc->ops->set_alarm)
354 err = -EINVAL;
355 else
356 err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
357
358 return err;
359}
360
361int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
362{
363 int err;
364
365 err = rtc_valid_tm(&alarm->time);
366 if (err != 0)
367 return err;
368
369 err = mutex_lock_interruptible(&rtc->ops_lock);
370 if (err)
371 return err;
372 if (rtc->aie_timer.enabled)
373 rtc_timer_remove(rtc, &rtc->aie_timer);
374
375 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
376 rtc->aie_timer.period = ktime_set(0, 0);
377 if (alarm->enabled)
378 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
379
380 mutex_unlock(&rtc->ops_lock);
381 return err;
382}
383EXPORT_SYMBOL_GPL(rtc_set_alarm);
384
385/* Called once per device from rtc_device_register */
386int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
387{
388 int err;
389 struct rtc_time now;
390
391 err = rtc_valid_tm(&alarm->time);
392 if (err != 0)
393 return err;
394
395 err = rtc_read_time(rtc, &now);
396 if (err)
397 return err;
398
399 err = mutex_lock_interruptible(&rtc->ops_lock);
400 if (err)
401 return err;
402
403 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
404 rtc->aie_timer.period = ktime_set(0, 0);
405
406 /* Alarm has to be enabled & in the futrure for us to enqueue it */
407 if (alarm->enabled && (rtc_tm_to_ktime(now).tv64 <
408 rtc->aie_timer.node.expires.tv64)) {
409
410 rtc->aie_timer.enabled = 1;
411 timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
412 }
413 mutex_unlock(&rtc->ops_lock);
414 return err;
415}
416EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
417
418
419
420int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
421{
422 int err = mutex_lock_interruptible(&rtc->ops_lock);
423 if (err)
424 return err;
425
426 if (rtc->aie_timer.enabled != enabled) {
427 if (enabled)
428 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
429 else
430 rtc_timer_remove(rtc, &rtc->aie_timer);
431 }
432
433 if (err)
434 /* nothing */;
435 else if (!rtc->ops)
436 err = -ENODEV;
437 else if (!rtc->ops->alarm_irq_enable)
438 err = -EINVAL;
439 else
440 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
441
442 mutex_unlock(&rtc->ops_lock);
443 return err;
444}
445EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
446
447int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
448{
449 int err = mutex_lock_interruptible(&rtc->ops_lock);
450 if (err)
451 return err;
452
453#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
454 if (enabled == 0 && rtc->uie_irq_active) {
455 mutex_unlock(&rtc->ops_lock);
456 return rtc_dev_update_irq_enable_emul(rtc, 0);
457 }
458#endif
459 /* make sure we're changing state */
460 if (rtc->uie_rtctimer.enabled == enabled)
461 goto out;
462
463 if (rtc->uie_unsupported) {
464 err = -EINVAL;
465 goto out;
466 }
467
468 if (enabled) {
469 struct rtc_time tm;
470 ktime_t now, onesec;
471
472 __rtc_read_time(rtc, &tm);
473 onesec = ktime_set(1, 0);
474 now = rtc_tm_to_ktime(tm);
475 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
476 rtc->uie_rtctimer.period = ktime_set(1, 0);
477 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
478 } else
479 rtc_timer_remove(rtc, &rtc->uie_rtctimer);
480
481out:
482 mutex_unlock(&rtc->ops_lock);
483#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
484 /*
485 * Enable emulation if the driver did not provide
486 * the update_irq_enable function pointer or if returned
487 * -EINVAL to signal that it has been configured without
488 * interrupts or that are not available at the moment.
489 */
490 if (err == -EINVAL)
491 err = rtc_dev_update_irq_enable_emul(rtc, enabled);
492#endif
493 return err;
494
495}
496EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
497
498
499/**
500 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
501 * @rtc: pointer to the rtc device
502 *
503 * This function is called when an AIE, UIE or PIE mode interrupt
504 * has occurred (or been emulated).
505 *
506 * Triggers the registered irq_task function callback.
507 */
508void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
509{
510 unsigned long flags;
511
512 /* mark one irq of the appropriate mode */
513 spin_lock_irqsave(&rtc->irq_lock, flags);
514 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF|mode);
515 spin_unlock_irqrestore(&rtc->irq_lock, flags);
516
517 /* call the task func */
518 spin_lock_irqsave(&rtc->irq_task_lock, flags);
519 if (rtc->irq_task)
520 rtc->irq_task->func(rtc->irq_task->private_data);
521 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
522
523 wake_up_interruptible(&rtc->irq_queue);
524 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
525}
526
527
528/**
529 * rtc_aie_update_irq - AIE mode rtctimer hook
530 * @private: pointer to the rtc_device
531 *
532 * This functions is called when the aie_timer expires.
533 */
534void rtc_aie_update_irq(void *private)
535{
536 struct rtc_device *rtc = (struct rtc_device *)private;
537 rtc_handle_legacy_irq(rtc, 1, RTC_AF);
538}
539
540
541/**
542 * rtc_uie_update_irq - UIE mode rtctimer hook
543 * @private: pointer to the rtc_device
544 *
545 * This functions is called when the uie_timer expires.
546 */
547void rtc_uie_update_irq(void *private)
548{
549 struct rtc_device *rtc = (struct rtc_device *)private;
550 rtc_handle_legacy_irq(rtc, 1, RTC_UF);
551}
552
553
554/**
555 * rtc_pie_update_irq - PIE mode hrtimer hook
556 * @timer: pointer to the pie mode hrtimer
557 *
558 * This function is used to emulate PIE mode interrupts
559 * using an hrtimer. This function is called when the periodic
560 * hrtimer expires.
561 */
562enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
563{
564 struct rtc_device *rtc;
565 ktime_t period;
566 int count;
567 rtc = container_of(timer, struct rtc_device, pie_timer);
568
569 period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
570 count = hrtimer_forward_now(timer, period);
571
572 rtc_handle_legacy_irq(rtc, count, RTC_PF);
573
574 return HRTIMER_RESTART;
575}
576
577/**
578 * rtc_update_irq - Triggered when a RTC interrupt occurs.
579 * @rtc: the rtc device
580 * @num: how many irqs are being reported (usually one)
581 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
582 * Context: any
583 */
584void rtc_update_irq(struct rtc_device *rtc,
585 unsigned long num, unsigned long events)
586{
587 if (unlikely(IS_ERR_OR_NULL(rtc)))
588 return;
589
590 pm_stay_awake(rtc->dev.parent);
591 schedule_work(&rtc->irqwork);
592}
593EXPORT_SYMBOL_GPL(rtc_update_irq);
594
595static int __rtc_match(struct device *dev, const void *data)
596{
597 const char *name = data;
598
599 if (strcmp(dev_name(dev), name) == 0)
600 return 1;
601 return 0;
602}
603
604struct rtc_device *rtc_class_open(const char *name)
605{
606 struct device *dev;
607 struct rtc_device *rtc = NULL;
608
609 dev = class_find_device(rtc_class, NULL, name, __rtc_match);
610 if (dev)
611 rtc = to_rtc_device(dev);
612
613 if (rtc) {
614 if (!try_module_get(rtc->owner)) {
615 put_device(dev);
616 rtc = NULL;
617 }
618 }
619
620 return rtc;
621}
622EXPORT_SYMBOL_GPL(rtc_class_open);
623
624void rtc_class_close(struct rtc_device *rtc)
625{
626 module_put(rtc->owner);
627 put_device(&rtc->dev);
628}
629EXPORT_SYMBOL_GPL(rtc_class_close);
630
631int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
632{
633 int retval = -EBUSY;
634
635 if (task == NULL || task->func == NULL)
636 return -EINVAL;
637
638 /* Cannot register while the char dev is in use */
639 if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
640 return -EBUSY;
641
642 spin_lock_irq(&rtc->irq_task_lock);
643 if (rtc->irq_task == NULL) {
644 rtc->irq_task = task;
645 retval = 0;
646 }
647 spin_unlock_irq(&rtc->irq_task_lock);
648
649 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
650
651 return retval;
652}
653EXPORT_SYMBOL_GPL(rtc_irq_register);
654
655void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task)
656{
657 spin_lock_irq(&rtc->irq_task_lock);
658 if (rtc->irq_task == task)
659 rtc->irq_task = NULL;
660 spin_unlock_irq(&rtc->irq_task_lock);
661}
662EXPORT_SYMBOL_GPL(rtc_irq_unregister);
663
664static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
665{
666 /*
667 * We always cancel the timer here first, because otherwise
668 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
669 * when we manage to start the timer before the callback
670 * returns HRTIMER_RESTART.
671 *
672 * We cannot use hrtimer_cancel() here as a running callback
673 * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
674 * would spin forever.
675 */
676 if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
677 return -1;
678
679 if (enabled) {
680 ktime_t period = ktime_set(0, NSEC_PER_SEC / rtc->irq_freq);
681
682 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
683 }
684 return 0;
685}
686
687/**
688 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
689 * @rtc: the rtc device
690 * @task: currently registered with rtc_irq_register()
691 * @enabled: true to enable periodic IRQs
692 * Context: any
693 *
694 * Note that rtc_irq_set_freq() should previously have been used to
695 * specify the desired frequency of periodic IRQ task->func() callbacks.
696 */
697int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled)
698{
699 int err = 0;
700 unsigned long flags;
701
702retry:
703 spin_lock_irqsave(&rtc->irq_task_lock, flags);
704 if (rtc->irq_task != NULL && task == NULL)
705 err = -EBUSY;
706 else if (rtc->irq_task != task)
707 err = -EACCES;
708 else {
709 if (rtc_update_hrtimer(rtc, enabled) < 0) {
710 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
711 cpu_relax();
712 goto retry;
713 }
714 rtc->pie_enabled = enabled;
715 }
716 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
717 return err;
718}
719EXPORT_SYMBOL_GPL(rtc_irq_set_state);
720
721/**
722 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
723 * @rtc: the rtc device
724 * @task: currently registered with rtc_irq_register()
725 * @freq: positive frequency with which task->func() will be called
726 * Context: any
727 *
728 * Note that rtc_irq_set_state() is used to enable or disable the
729 * periodic IRQs.
730 */
731int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
732{
733 int err = 0;
734 unsigned long flags;
735
736 if (freq <= 0 || freq > RTC_MAX_FREQ)
737 return -EINVAL;
738retry:
739 spin_lock_irqsave(&rtc->irq_task_lock, flags);
740 if (rtc->irq_task != NULL && task == NULL)
741 err = -EBUSY;
742 else if (rtc->irq_task != task)
743 err = -EACCES;
744 else {
745 rtc->irq_freq = freq;
746 if (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0) {
747 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
748 cpu_relax();
749 goto retry;
750 }
751 }
752 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
753 return err;
754}
755EXPORT_SYMBOL_GPL(rtc_irq_set_freq);
756
757/**
758 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
759 * @rtc rtc device
760 * @timer timer being added.
761 *
762 * Enqueues a timer onto the rtc devices timerqueue and sets
763 * the next alarm event appropriately.
764 *
765 * Sets the enabled bit on the added timer.
766 *
767 * Must hold ops_lock for proper serialization of timerqueue
768 */
769static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
770{
771 timer->enabled = 1;
772 timerqueue_add(&rtc->timerqueue, &timer->node);
773 if (&timer->node == timerqueue_getnext(&rtc->timerqueue)) {
774 struct rtc_wkalrm alarm;
775 int err;
776 alarm.time = rtc_ktime_to_tm(timer->node.expires);
777 alarm.enabled = 1;
778 err = __rtc_set_alarm(rtc, &alarm);
779 if (err == -ETIME) {
780 pm_stay_awake(rtc->dev.parent);
781 schedule_work(&rtc->irqwork);
782 } else if (err) {
783 timerqueue_del(&rtc->timerqueue, &timer->node);
784 timer->enabled = 0;
785 return err;
786 }
787 }
788 return 0;
789}
790
791static void rtc_alarm_disable(struct rtc_device *rtc)
792{
793 if (!rtc->ops || !rtc->ops->alarm_irq_enable)
794 return;
795
796 rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
797}
798
799/**
800 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
801 * @rtc rtc device
802 * @timer timer being removed.
803 *
804 * Removes a timer onto the rtc devices timerqueue and sets
805 * the next alarm event appropriately.
806 *
807 * Clears the enabled bit on the removed timer.
808 *
809 * Must hold ops_lock for proper serialization of timerqueue
810 */
811static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
812{
813 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
814 timerqueue_del(&rtc->timerqueue, &timer->node);
815 timer->enabled = 0;
816 if (next == &timer->node) {
817 struct rtc_wkalrm alarm;
818 int err;
819 next = timerqueue_getnext(&rtc->timerqueue);
820 if (!next) {
821 rtc_alarm_disable(rtc);
822 return;
823 }
824 alarm.time = rtc_ktime_to_tm(next->expires);
825 alarm.enabled = 1;
826 err = __rtc_set_alarm(rtc, &alarm);
827 if (err == -ETIME) {
828 pm_stay_awake(rtc->dev.parent);
829 schedule_work(&rtc->irqwork);
830 }
831 }
832}
833
834/**
835 * rtc_timer_do_work - Expires rtc timers
836 * @rtc rtc device
837 * @timer timer being removed.
838 *
839 * Expires rtc timers. Reprograms next alarm event if needed.
840 * Called via worktask.
841 *
842 * Serializes access to timerqueue via ops_lock mutex
843 */
844void rtc_timer_do_work(struct work_struct *work)
845{
846 struct rtc_timer *timer;
847 struct timerqueue_node *next;
848 ktime_t now;
849 struct rtc_time tm;
850
851 struct rtc_device *rtc =
852 container_of(work, struct rtc_device, irqwork);
853
854 mutex_lock(&rtc->ops_lock);
855again:
856 __rtc_read_time(rtc, &tm);
857 now = rtc_tm_to_ktime(tm);
858 while ((next = timerqueue_getnext(&rtc->timerqueue))) {
859 if (next->expires.tv64 > now.tv64)
860 break;
861
862 /* expire timer */
863 timer = container_of(next, struct rtc_timer, node);
864 timerqueue_del(&rtc->timerqueue, &timer->node);
865 timer->enabled = 0;
866 if (timer->task.func)
867 timer->task.func(timer->task.private_data);
868
869 /* Re-add/fwd periodic timers */
870 if (ktime_to_ns(timer->period)) {
871 timer->node.expires = ktime_add(timer->node.expires,
872 timer->period);
873 timer->enabled = 1;
874 timerqueue_add(&rtc->timerqueue, &timer->node);
875 }
876 }
877
878 /* Set next alarm */
879 if (next) {
880 struct rtc_wkalrm alarm;
881 int err;
882 alarm.time = rtc_ktime_to_tm(next->expires);
883 alarm.enabled = 1;
884 err = __rtc_set_alarm(rtc, &alarm);
885 if (err == -ETIME)
886 goto again;
887 } else
888 rtc_alarm_disable(rtc);
889
890 pm_relax(rtc->dev.parent);
891 mutex_unlock(&rtc->ops_lock);
892}
893
894
895/* rtc_timer_init - Initializes an rtc_timer
896 * @timer: timer to be intiialized
897 * @f: function pointer to be called when timer fires
898 * @data: private data passed to function pointer
899 *
900 * Kernel interface to initializing an rtc_timer.
901 */
902void rtc_timer_init(struct rtc_timer *timer, void (*f)(void *p), void *data)
903{
904 timerqueue_init(&timer->node);
905 timer->enabled = 0;
906 timer->task.func = f;
907 timer->task.private_data = data;
908}
909
910/* rtc_timer_start - Sets an rtc_timer to fire in the future
911 * @ rtc: rtc device to be used
912 * @ timer: timer being set
913 * @ expires: time at which to expire the timer
914 * @ period: period that the timer will recur
915 *
916 * Kernel interface to set an rtc_timer
917 */
918int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
919 ktime_t expires, ktime_t period)
920{
921 int ret = 0;
922 mutex_lock(&rtc->ops_lock);
923 if (timer->enabled)
924 rtc_timer_remove(rtc, timer);
925
926 timer->node.expires = expires;
927 timer->period = period;
928
929 ret = rtc_timer_enqueue(rtc, timer);
930
931 mutex_unlock(&rtc->ops_lock);
932 return ret;
933}
934
935/* rtc_timer_cancel - Stops an rtc_timer
936 * @ rtc: rtc device to be used
937 * @ timer: timer being set
938 *
939 * Kernel interface to cancel an rtc_timer
940 */
941int rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
942{
943 int ret = 0;
944 mutex_lock(&rtc->ops_lock);
945 if (timer->enabled)
946 rtc_timer_remove(rtc, timer);
947 mutex_unlock(&rtc->ops_lock);
948 return ret;
949}
950
951