projects/linux·blob v3.2 · refs

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