projects/linux·blob v3.18 · refs

963 lines · 23.8 KiB

1/*
2 * RTC subsystem, interface functions
3 *
4 * Copyright (C) 2005 Tower Technologies
5 * Author: Alessandro Zummo <[email protected]>
6 *
7 * based on arch/arm/common/rtctime.c
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12*/
13
14#include <linux/rtc.h>
15#include <linux/sched.h>
16#include <linux/module.h>
17#include <linux/log2.h>
18#include <linux/workqueue.h>
19
20static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer);
21static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer);
22
23static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
24{
25 int err;
26 if (!rtc->ops)
27 err = -ENODEV;
28 else if (!rtc->ops->read_time)
29 err = -EINVAL;
30 else {
31 memset(tm, 0, sizeof(struct rtc_time));
32 err = rtc->ops->read_time(rtc->dev.parent, tm);
33 }
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 (!is_leap_year(alarm->time.tm_year + 1900)
296 && rtc_valid_tm(&alarm->time) != 0);
297 break;
298
299 default:
300 dev_warn(&rtc->dev, "alarm rollover not handled\n");
301 }
302
303done:
304 err = rtc_valid_tm(&alarm->time);
305
306 if (err) {
307 dev_warn(&rtc->dev, "invalid alarm value: %d-%d-%d %d:%d:%d\n",
308 alarm->time.tm_year + 1900, alarm->time.tm_mon + 1,
309 alarm->time.tm_mday, alarm->time.tm_hour, alarm->time.tm_min,
310 alarm->time.tm_sec);
311 }
312
313 return err;
314}
315
316int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
317{
318 int err;
319
320 err = mutex_lock_interruptible(&rtc->ops_lock);
321 if (err)
322 return err;
323 if (rtc->ops == NULL)
324 err = -ENODEV;
325 else if (!rtc->ops->read_alarm)
326 err = -EINVAL;
327 else {
328 memset(alarm, 0, sizeof(struct rtc_wkalrm));
329 alarm->enabled = rtc->aie_timer.enabled;
330 alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
331 }
332 mutex_unlock(&rtc->ops_lock);
333
334 return err;
335}
336EXPORT_SYMBOL_GPL(rtc_read_alarm);
337
338static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
339{
340 struct rtc_time tm;
341 long now, scheduled;
342 int err;
343
344 err = rtc_valid_tm(&alarm->time);
345 if (err)
346 return err;
347 rtc_tm_to_time(&alarm->time, &scheduled);
348
349 /* Make sure we're not setting alarms in the past */
350 err = __rtc_read_time(rtc, &tm);
351 if (err)
352 return err;
353 rtc_tm_to_time(&tm, &now);
354 if (scheduled <= now)
355 return -ETIME;
356 /*
357 * XXX - We just checked to make sure the alarm time is not
358 * in the past, but there is still a race window where if
359 * the is alarm set for the next second and the second ticks
360 * over right here, before we set the alarm.
361 */
362
363 if (!rtc->ops)
364 err = -ENODEV;
365 else if (!rtc->ops->set_alarm)
366 err = -EINVAL;
367 else
368 err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
369
370 return err;
371}
372
373int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
374{
375 int err;
376
377 err = rtc_valid_tm(&alarm->time);
378 if (err != 0)
379 return err;
380
381 err = mutex_lock_interruptible(&rtc->ops_lock);
382 if (err)
383 return err;
384 if (rtc->aie_timer.enabled)
385 rtc_timer_remove(rtc, &rtc->aie_timer);
386
387 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
388 rtc->aie_timer.period = ktime_set(0, 0);
389 if (alarm->enabled)
390 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
391
392 mutex_unlock(&rtc->ops_lock);
393 return err;
394}
395EXPORT_SYMBOL_GPL(rtc_set_alarm);
396
397/* Called once per device from rtc_device_register */
398int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
399{
400 int err;
401 struct rtc_time now;
402
403 err = rtc_valid_tm(&alarm->time);
404 if (err != 0)
405 return err;
406
407 err = rtc_read_time(rtc, &now);
408 if (err)
409 return err;
410
411 err = mutex_lock_interruptible(&rtc->ops_lock);
412 if (err)
413 return err;
414
415 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
416 rtc->aie_timer.period = ktime_set(0, 0);
417
418 /* Alarm has to be enabled & in the futrure for us to enqueue it */
419 if (alarm->enabled && (rtc_tm_to_ktime(now).tv64 <
420 rtc->aie_timer.node.expires.tv64)) {
421
422 rtc->aie_timer.enabled = 1;
423 timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
424 }
425 mutex_unlock(&rtc->ops_lock);
426 return err;
427}
428EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
429
430
431
432int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
433{
434 int err = mutex_lock_interruptible(&rtc->ops_lock);
435 if (err)
436 return err;
437
438 if (rtc->aie_timer.enabled != enabled) {
439 if (enabled)
440 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
441 else
442 rtc_timer_remove(rtc, &rtc->aie_timer);
443 }
444
445 if (err)
446 /* nothing */;
447 else if (!rtc->ops)
448 err = -ENODEV;
449 else if (!rtc->ops->alarm_irq_enable)
450 err = -EINVAL;
451 else
452 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
453
454 mutex_unlock(&rtc->ops_lock);
455 return err;
456}
457EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
458
459int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
460{
461 int err = mutex_lock_interruptible(&rtc->ops_lock);
462 if (err)
463 return err;
464
465#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
466 if (enabled == 0 && rtc->uie_irq_active) {
467 mutex_unlock(&rtc->ops_lock);
468 return rtc_dev_update_irq_enable_emul(rtc, 0);
469 }
470#endif
471 /* make sure we're changing state */
472 if (rtc->uie_rtctimer.enabled == enabled)
473 goto out;
474
475 if (rtc->uie_unsupported) {
476 err = -EINVAL;
477 goto out;
478 }
479
480 if (enabled) {
481 struct rtc_time tm;
482 ktime_t now, onesec;
483
484 __rtc_read_time(rtc, &tm);
485 onesec = ktime_set(1, 0);
486 now = rtc_tm_to_ktime(tm);
487 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
488 rtc->uie_rtctimer.period = ktime_set(1, 0);
489 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
490 } else
491 rtc_timer_remove(rtc, &rtc->uie_rtctimer);
492
493out:
494 mutex_unlock(&rtc->ops_lock);
495#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
496 /*
497 * Enable emulation if the driver did not provide
498 * the update_irq_enable function pointer or if returned
499 * -EINVAL to signal that it has been configured without
500 * interrupts or that are not available at the moment.
501 */
502 if (err == -EINVAL)
503 err = rtc_dev_update_irq_enable_emul(rtc, enabled);
504#endif
505 return err;
506
507}
508EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
509
510
511/**
512 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
513 * @rtc: pointer to the rtc device
514 *
515 * This function is called when an AIE, UIE or PIE mode interrupt
516 * has occurred (or been emulated).
517 *
518 * Triggers the registered irq_task function callback.
519 */
520void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
521{
522 unsigned long flags;
523
524 /* mark one irq of the appropriate mode */
525 spin_lock_irqsave(&rtc->irq_lock, flags);
526 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF|mode);
527 spin_unlock_irqrestore(&rtc->irq_lock, flags);
528
529 /* call the task func */
530 spin_lock_irqsave(&rtc->irq_task_lock, flags);
531 if (rtc->irq_task)
532 rtc->irq_task->func(rtc->irq_task->private_data);
533 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
534
535 wake_up_interruptible(&rtc->irq_queue);
536 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
537}
538
539
540/**
541 * rtc_aie_update_irq - AIE mode rtctimer hook
542 * @private: pointer to the rtc_device
543 *
544 * This functions is called when the aie_timer expires.
545 */
546void rtc_aie_update_irq(void *private)
547{
548 struct rtc_device *rtc = (struct rtc_device *)private;
549 rtc_handle_legacy_irq(rtc, 1, RTC_AF);
550}
551
552
553/**
554 * rtc_uie_update_irq - UIE mode rtctimer hook
555 * @private: pointer to the rtc_device
556 *
557 * This functions is called when the uie_timer expires.
558 */
559void rtc_uie_update_irq(void *private)
560{
561 struct rtc_device *rtc = (struct rtc_device *)private;
562 rtc_handle_legacy_irq(rtc, 1, RTC_UF);
563}
564
565
566/**
567 * rtc_pie_update_irq - PIE mode hrtimer hook
568 * @timer: pointer to the pie mode hrtimer
569 *
570 * This function is used to emulate PIE mode interrupts
571 * using an hrtimer. This function is called when the periodic
572 * hrtimer expires.
573 */
574enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
575{
576 struct rtc_device *rtc;
577 ktime_t period;
578 int count;
579 rtc = container_of(timer, struct rtc_device, pie_timer);
580
581 period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
582 count = hrtimer_forward_now(timer, period);
583
584 rtc_handle_legacy_irq(rtc, count, RTC_PF);
585
586 return HRTIMER_RESTART;
587}
588
589/**
590 * rtc_update_irq - Triggered when a RTC interrupt occurs.
591 * @rtc: the rtc device
592 * @num: how many irqs are being reported (usually one)
593 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
594 * Context: any
595 */
596void rtc_update_irq(struct rtc_device *rtc,
597 unsigned long num, unsigned long events)
598{
599 if (unlikely(IS_ERR_OR_NULL(rtc)))
600 return;
601
602 pm_stay_awake(rtc->dev.parent);
603 schedule_work(&rtc->irqwork);
604}
605EXPORT_SYMBOL_GPL(rtc_update_irq);
606
607static int __rtc_match(struct device *dev, const void *data)
608{
609 const char *name = data;
610
611 if (strcmp(dev_name(dev), name) == 0)
612 return 1;
613 return 0;
614}
615
616struct rtc_device *rtc_class_open(const char *name)
617{
618 struct device *dev;
619 struct rtc_device *rtc = NULL;
620
621 dev = class_find_device(rtc_class, NULL, name, __rtc_match);
622 if (dev)
623 rtc = to_rtc_device(dev);
624
625 if (rtc) {
626 if (!try_module_get(rtc->owner)) {
627 put_device(dev);
628 rtc = NULL;
629 }
630 }
631
632 return rtc;
633}
634EXPORT_SYMBOL_GPL(rtc_class_open);
635
636void rtc_class_close(struct rtc_device *rtc)
637{
638 module_put(rtc->owner);
639 put_device(&rtc->dev);
640}
641EXPORT_SYMBOL_GPL(rtc_class_close);
642
643int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
644{
645 int retval = -EBUSY;
646
647 if (task == NULL || task->func == NULL)
648 return -EINVAL;
649
650 /* Cannot register while the char dev is in use */
651 if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
652 return -EBUSY;
653
654 spin_lock_irq(&rtc->irq_task_lock);
655 if (rtc->irq_task == NULL) {
656 rtc->irq_task = task;
657 retval = 0;
658 }
659 spin_unlock_irq(&rtc->irq_task_lock);
660
661 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
662
663 return retval;
664}
665EXPORT_SYMBOL_GPL(rtc_irq_register);
666
667void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task)
668{
669 spin_lock_irq(&rtc->irq_task_lock);
670 if (rtc->irq_task == task)
671 rtc->irq_task = NULL;
672 spin_unlock_irq(&rtc->irq_task_lock);
673}
674EXPORT_SYMBOL_GPL(rtc_irq_unregister);
675
676static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
677{
678 /*
679 * We always cancel the timer here first, because otherwise
680 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
681 * when we manage to start the timer before the callback
682 * returns HRTIMER_RESTART.
683 *
684 * We cannot use hrtimer_cancel() here as a running callback
685 * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
686 * would spin forever.
687 */
688 if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
689 return -1;
690
691 if (enabled) {
692 ktime_t period = ktime_set(0, NSEC_PER_SEC / rtc->irq_freq);
693
694 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
695 }
696 return 0;
697}
698
699/**
700 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
701 * @rtc: the rtc device
702 * @task: currently registered with rtc_irq_register()
703 * @enabled: true to enable periodic IRQs
704 * Context: any
705 *
706 * Note that rtc_irq_set_freq() should previously have been used to
707 * specify the desired frequency of periodic IRQ task->func() callbacks.
708 */
709int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled)
710{
711 int err = 0;
712 unsigned long flags;
713
714retry:
715 spin_lock_irqsave(&rtc->irq_task_lock, flags);
716 if (rtc->irq_task != NULL && task == NULL)
717 err = -EBUSY;
718 else if (rtc->irq_task != task)
719 err = -EACCES;
720 else {
721 if (rtc_update_hrtimer(rtc, enabled) < 0) {
722 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
723 cpu_relax();
724 goto retry;
725 }
726 rtc->pie_enabled = enabled;
727 }
728 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
729 return err;
730}
731EXPORT_SYMBOL_GPL(rtc_irq_set_state);
732
733/**
734 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
735 * @rtc: the rtc device
736 * @task: currently registered with rtc_irq_register()
737 * @freq: positive frequency with which task->func() will be called
738 * Context: any
739 *
740 * Note that rtc_irq_set_state() is used to enable or disable the
741 * periodic IRQs.
742 */
743int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
744{
745 int err = 0;
746 unsigned long flags;
747
748 if (freq <= 0 || freq > RTC_MAX_FREQ)
749 return -EINVAL;
750retry:
751 spin_lock_irqsave(&rtc->irq_task_lock, flags);
752 if (rtc->irq_task != NULL && task == NULL)
753 err = -EBUSY;
754 else if (rtc->irq_task != task)
755 err = -EACCES;
756 else {
757 rtc->irq_freq = freq;
758 if (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0) {
759 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
760 cpu_relax();
761 goto retry;
762 }
763 }
764 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
765 return err;
766}
767EXPORT_SYMBOL_GPL(rtc_irq_set_freq);
768
769/**
770 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
771 * @rtc rtc device
772 * @timer timer being added.
773 *
774 * Enqueues a timer onto the rtc devices timerqueue and sets
775 * the next alarm event appropriately.
776 *
777 * Sets the enabled bit on the added timer.
778 *
779 * Must hold ops_lock for proper serialization of timerqueue
780 */
781static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
782{
783 timer->enabled = 1;
784 timerqueue_add(&rtc->timerqueue, &timer->node);
785 if (&timer->node == timerqueue_getnext(&rtc->timerqueue)) {
786 struct rtc_wkalrm alarm;
787 int err;
788 alarm.time = rtc_ktime_to_tm(timer->node.expires);
789 alarm.enabled = 1;
790 err = __rtc_set_alarm(rtc, &alarm);
791 if (err == -ETIME) {
792 pm_stay_awake(rtc->dev.parent);
793 schedule_work(&rtc->irqwork);
794 } else if (err) {
795 timerqueue_del(&rtc->timerqueue, &timer->node);
796 timer->enabled = 0;
797 return err;
798 }
799 }
800 return 0;
801}
802
803static void rtc_alarm_disable(struct rtc_device *rtc)
804{
805 if (!rtc->ops || !rtc->ops->alarm_irq_enable)
806 return;
807
808 rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
809}
810
811/**
812 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
813 * @rtc rtc device
814 * @timer timer being removed.
815 *
816 * Removes a timer onto the rtc devices timerqueue and sets
817 * the next alarm event appropriately.
818 *
819 * Clears the enabled bit on the removed timer.
820 *
821 * Must hold ops_lock for proper serialization of timerqueue
822 */
823static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
824{
825 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
826 timerqueue_del(&rtc->timerqueue, &timer->node);
827 timer->enabled = 0;
828 if (next == &timer->node) {
829 struct rtc_wkalrm alarm;
830 int err;
831 next = timerqueue_getnext(&rtc->timerqueue);
832 if (!next) {
833 rtc_alarm_disable(rtc);
834 return;
835 }
836 alarm.time = rtc_ktime_to_tm(next->expires);
837 alarm.enabled = 1;
838 err = __rtc_set_alarm(rtc, &alarm);
839 if (err == -ETIME) {
840 pm_stay_awake(rtc->dev.parent);
841 schedule_work(&rtc->irqwork);
842 }
843 }
844}
845
846/**
847 * rtc_timer_do_work - Expires rtc timers
848 * @rtc rtc device
849 * @timer timer being removed.
850 *
851 * Expires rtc timers. Reprograms next alarm event if needed.
852 * Called via worktask.
853 *
854 * Serializes access to timerqueue via ops_lock mutex
855 */
856void rtc_timer_do_work(struct work_struct *work)
857{
858 struct rtc_timer *timer;
859 struct timerqueue_node *next;
860 ktime_t now;
861 struct rtc_time tm;
862
863 struct rtc_device *rtc =
864 container_of(work, struct rtc_device, irqwork);
865
866 mutex_lock(&rtc->ops_lock);
867again:
868 __rtc_read_time(rtc, &tm);
869 now = rtc_tm_to_ktime(tm);
870 while ((next = timerqueue_getnext(&rtc->timerqueue))) {
871 if (next->expires.tv64 > now.tv64)
872 break;
873
874 /* expire timer */
875 timer = container_of(next, struct rtc_timer, node);
876 timerqueue_del(&rtc->timerqueue, &timer->node);
877 timer->enabled = 0;
878 if (timer->task.func)
879 timer->task.func(timer->task.private_data);
880
881 /* Re-add/fwd periodic timers */
882 if (ktime_to_ns(timer->period)) {
883 timer->node.expires = ktime_add(timer->node.expires,
884 timer->period);
885 timer->enabled = 1;
886 timerqueue_add(&rtc->timerqueue, &timer->node);
887 }
888 }
889
890 /* Set next alarm */
891 if (next) {
892 struct rtc_wkalrm alarm;
893 int err;
894 alarm.time = rtc_ktime_to_tm(next->expires);
895 alarm.enabled = 1;
896 err = __rtc_set_alarm(rtc, &alarm);
897 if (err == -ETIME)
898 goto again;
899 } else
900 rtc_alarm_disable(rtc);
901
902 pm_relax(rtc->dev.parent);
903 mutex_unlock(&rtc->ops_lock);
904}
905
906
907/* rtc_timer_init - Initializes an rtc_timer
908 * @timer: timer to be intiialized
909 * @f: function pointer to be called when timer fires
910 * @data: private data passed to function pointer
911 *
912 * Kernel interface to initializing an rtc_timer.
913 */
914void rtc_timer_init(struct rtc_timer *timer, void (*f)(void *p), void *data)
915{
916 timerqueue_init(&timer->node);
917 timer->enabled = 0;
918 timer->task.func = f;
919 timer->task.private_data = data;
920}
921
922/* rtc_timer_start - Sets an rtc_timer to fire in the future
923 * @ rtc: rtc device to be used
924 * @ timer: timer being set
925 * @ expires: time at which to expire the timer
926 * @ period: period that the timer will recur
927 *
928 * Kernel interface to set an rtc_timer
929 */
930int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
931 ktime_t expires, ktime_t period)
932{
933 int ret = 0;
934 mutex_lock(&rtc->ops_lock);
935 if (timer->enabled)
936 rtc_timer_remove(rtc, timer);
937
938 timer->node.expires = expires;
939 timer->period = period;
940
941 ret = rtc_timer_enqueue(rtc, timer);
942
943 mutex_unlock(&rtc->ops_lock);
944 return ret;
945}
946
947/* rtc_timer_cancel - Stops an rtc_timer
948 * @ rtc: rtc device to be used
949 * @ timer: timer being set
950 *
951 * Kernel interface to cancel an rtc_timer
952 */
953int rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
954{
955 int ret = 0;
956 mutex_lock(&rtc->ops_lock);
957 if (timer->enabled)
958 rtc_timer_remove(rtc, timer);
959 mutex_unlock(&rtc->ops_lock);
960 return ret;
961}
962
963