projects/linux·blob v4.11 · refs

1018 lines · 25.2 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 if (err < 0) {
34 dev_dbg(&rtc->dev, "read_time: fail to read: %d\n",
35 err);
36 return err;
37 }
38
39 err = rtc_valid_tm(tm);
40 if (err < 0)
41 dev_dbg(&rtc->dev, "read_time: rtc_time isn't valid\n");
42 }
43 return err;
44}
45
46int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
47{
48 int err;
49
50 err = mutex_lock_interruptible(&rtc->ops_lock);
51 if (err)
52 return err;
53
54 err = __rtc_read_time(rtc, tm);
55 mutex_unlock(&rtc->ops_lock);
56 return err;
57}
58EXPORT_SYMBOL_GPL(rtc_read_time);
59
60int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
61{
62 int err;
63
64 err = rtc_valid_tm(tm);
65 if (err != 0)
66 return err;
67
68 err = mutex_lock_interruptible(&rtc->ops_lock);
69 if (err)
70 return err;
71
72 if (!rtc->ops)
73 err = -ENODEV;
74 else if (rtc->ops->set_time)
75 err = rtc->ops->set_time(rtc->dev.parent, tm);
76 else if (rtc->ops->set_mmss64) {
77 time64_t secs64 = rtc_tm_to_time64(tm);
78
79 err = rtc->ops->set_mmss64(rtc->dev.parent, secs64);
80 } else if (rtc->ops->set_mmss) {
81 time64_t secs64 = rtc_tm_to_time64(tm);
82 err = rtc->ops->set_mmss(rtc->dev.parent, secs64);
83 } else
84 err = -EINVAL;
85
86 pm_stay_awake(rtc->dev.parent);
87 mutex_unlock(&rtc->ops_lock);
88 /* A timer might have just expired */
89 schedule_work(&rtc->irqwork);
90 return err;
91}
92EXPORT_SYMBOL_GPL(rtc_set_time);
93
94static int rtc_read_alarm_internal(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
95{
96 int err;
97
98 err = mutex_lock_interruptible(&rtc->ops_lock);
99 if (err)
100 return err;
101
102 if (rtc->ops == NULL)
103 err = -ENODEV;
104 else if (!rtc->ops->read_alarm)
105 err = -EINVAL;
106 else {
107 alarm->enabled = 0;
108 alarm->pending = 0;
109 alarm->time.tm_sec = -1;
110 alarm->time.tm_min = -1;
111 alarm->time.tm_hour = -1;
112 alarm->time.tm_mday = -1;
113 alarm->time.tm_mon = -1;
114 alarm->time.tm_year = -1;
115 alarm->time.tm_wday = -1;
116 alarm->time.tm_yday = -1;
117 alarm->time.tm_isdst = -1;
118 err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
119 }
120
121 mutex_unlock(&rtc->ops_lock);
122 return err;
123}
124
125int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
126{
127 int err;
128 struct rtc_time before, now;
129 int first_time = 1;
130 time64_t t_now, t_alm;
131 enum { none, day, month, year } missing = none;
132 unsigned days;
133
134 /* The lower level RTC driver may return -1 in some fields,
135 * creating invalid alarm->time values, for reasons like:
136 *
137 * - The hardware may not be capable of filling them in;
138 * many alarms match only on time-of-day fields, not
139 * day/month/year calendar data.
140 *
141 * - Some hardware uses illegal values as "wildcard" match
142 * values, which non-Linux firmware (like a BIOS) may try
143 * to set up as e.g. "alarm 15 minutes after each hour".
144 * Linux uses only oneshot alarms.
145 *
146 * When we see that here, we deal with it by using values from
147 * a current RTC timestamp for any missing (-1) values. The
148 * RTC driver prevents "periodic alarm" modes.
149 *
150 * But this can be racey, because some fields of the RTC timestamp
151 * may have wrapped in the interval since we read the RTC alarm,
152 * which would lead to us inserting inconsistent values in place
153 * of the -1 fields.
154 *
155 * Reading the alarm and timestamp in the reverse sequence
156 * would have the same race condition, and not solve the issue.
157 *
158 * So, we must first read the RTC timestamp,
159 * then read the RTC alarm value,
160 * and then read a second RTC timestamp.
161 *
162 * If any fields of the second timestamp have changed
163 * when compared with the first timestamp, then we know
164 * our timestamp may be inconsistent with that used by
165 * the low-level rtc_read_alarm_internal() function.
166 *
167 * So, when the two timestamps disagree, we just loop and do
168 * the process again to get a fully consistent set of values.
169 *
170 * This could all instead be done in the lower level driver,
171 * but since more than one lower level RTC implementation needs it,
172 * then it's probably best best to do it here instead of there..
173 */
174
175 /* Get the "before" timestamp */
176 err = rtc_read_time(rtc, &before);
177 if (err < 0)
178 return err;
179 do {
180 if (!first_time)
181 memcpy(&before, &now, sizeof(struct rtc_time));
182 first_time = 0;
183
184 /* get the RTC alarm values, which may be incomplete */
185 err = rtc_read_alarm_internal(rtc, alarm);
186 if (err)
187 return err;
188
189 /* full-function RTCs won't have such missing fields */
190 if (rtc_valid_tm(&alarm->time) == 0)
191 return 0;
192
193 /* get the "after" timestamp, to detect wrapped fields */
194 err = rtc_read_time(rtc, &now);
195 if (err < 0)
196 return err;
197
198 /* note that tm_sec is a "don't care" value here: */
199 } while ( before.tm_min != now.tm_min
200 || before.tm_hour != now.tm_hour
201 || before.tm_mon != now.tm_mon
202 || before.tm_year != now.tm_year);
203
204 /* Fill in the missing alarm fields using the timestamp; we
205 * know there's at least one since alarm->time is invalid.
206 */
207 if (alarm->time.tm_sec == -1)
208 alarm->time.tm_sec = now.tm_sec;
209 if (alarm->time.tm_min == -1)
210 alarm->time.tm_min = now.tm_min;
211 if (alarm->time.tm_hour == -1)
212 alarm->time.tm_hour = now.tm_hour;
213
214 /* For simplicity, only support date rollover for now */
215 if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) {
216 alarm->time.tm_mday = now.tm_mday;
217 missing = day;
218 }
219 if ((unsigned)alarm->time.tm_mon >= 12) {
220 alarm->time.tm_mon = now.tm_mon;
221 if (missing == none)
222 missing = month;
223 }
224 if (alarm->time.tm_year == -1) {
225 alarm->time.tm_year = now.tm_year;
226 if (missing == none)
227 missing = year;
228 }
229
230 /* with luck, no rollover is needed */
231 t_now = rtc_tm_to_time64(&now);
232 t_alm = rtc_tm_to_time64(&alarm->time);
233 if (t_now < t_alm)
234 goto done;
235
236 switch (missing) {
237
238 /* 24 hour rollover ... if it's now 10am Monday, an alarm that
239 * that will trigger at 5am will do so at 5am Tuesday, which
240 * could also be in the next month or year. This is a common
241 * case, especially for PCs.
242 */
243 case day:
244 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
245 t_alm += 24 * 60 * 60;
246 rtc_time64_to_tm(t_alm, &alarm->time);
247 break;
248
249 /* Month rollover ... if it's the 31th, an alarm on the 3rd will
250 * be next month. An alarm matching on the 30th, 29th, or 28th
251 * may end up in the month after that! Many newer PCs support
252 * this type of alarm.
253 */
254 case month:
255 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
256 do {
257 if (alarm->time.tm_mon < 11)
258 alarm->time.tm_mon++;
259 else {
260 alarm->time.tm_mon = 0;
261 alarm->time.tm_year++;
262 }
263 days = rtc_month_days(alarm->time.tm_mon,
264 alarm->time.tm_year);
265 } while (days < alarm->time.tm_mday);
266 break;
267
268 /* Year rollover ... easy except for leap years! */
269 case year:
270 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
271 do {
272 alarm->time.tm_year++;
273 } while (!is_leap_year(alarm->time.tm_year + 1900)
274 && rtc_valid_tm(&alarm->time) != 0);
275 break;
276
277 default:
278 dev_warn(&rtc->dev, "alarm rollover not handled\n");
279 }
280
281done:
282 err = rtc_valid_tm(&alarm->time);
283
284 if (err) {
285 dev_warn(&rtc->dev, "invalid alarm value: %d-%d-%d %d:%d:%d\n",
286 alarm->time.tm_year + 1900, alarm->time.tm_mon + 1,
287 alarm->time.tm_mday, alarm->time.tm_hour, alarm->time.tm_min,
288 alarm->time.tm_sec);
289 }
290
291 return err;
292}
293
294int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
295{
296 int err;
297
298 err = mutex_lock_interruptible(&rtc->ops_lock);
299 if (err)
300 return err;
301 if (rtc->ops == NULL)
302 err = -ENODEV;
303 else if (!rtc->ops->read_alarm)
304 err = -EINVAL;
305 else {
306 memset(alarm, 0, sizeof(struct rtc_wkalrm));
307 alarm->enabled = rtc->aie_timer.enabled;
308 alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
309 }
310 mutex_unlock(&rtc->ops_lock);
311
312 return err;
313}
314EXPORT_SYMBOL_GPL(rtc_read_alarm);
315
316static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
317{
318 struct rtc_time tm;
319 time64_t now, scheduled;
320 int err;
321
322 err = rtc_valid_tm(&alarm->time);
323 if (err)
324 return err;
325 scheduled = rtc_tm_to_time64(&alarm->time);
326
327 /* Make sure we're not setting alarms in the past */
328 err = __rtc_read_time(rtc, &tm);
329 if (err)
330 return err;
331 now = rtc_tm_to_time64(&tm);
332 if (scheduled <= now)
333 return -ETIME;
334 /*
335 * XXX - We just checked to make sure the alarm time is not
336 * in the past, but there is still a race window where if
337 * the is alarm set for the next second and the second ticks
338 * over right here, before we set the alarm.
339 */
340
341 if (!rtc->ops)
342 err = -ENODEV;
343 else if (!rtc->ops->set_alarm)
344 err = -EINVAL;
345 else
346 err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
347
348 return err;
349}
350
351int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
352{
353 int err;
354
355 err = rtc_valid_tm(&alarm->time);
356 if (err != 0)
357 return err;
358
359 err = mutex_lock_interruptible(&rtc->ops_lock);
360 if (err)
361 return err;
362 if (rtc->aie_timer.enabled)
363 rtc_timer_remove(rtc, &rtc->aie_timer);
364
365 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
366 rtc->aie_timer.period = 0;
367 if (alarm->enabled)
368 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
369
370 mutex_unlock(&rtc->ops_lock);
371 return err;
372}
373EXPORT_SYMBOL_GPL(rtc_set_alarm);
374
375/* Called once per device from rtc_device_register */
376int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
377{
378 int err;
379 struct rtc_time now;
380
381 err = rtc_valid_tm(&alarm->time);
382 if (err != 0)
383 return err;
384
385 err = rtc_read_time(rtc, &now);
386 if (err)
387 return err;
388
389 err = mutex_lock_interruptible(&rtc->ops_lock);
390 if (err)
391 return err;
392
393 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
394 rtc->aie_timer.period = 0;
395
396 /* Alarm has to be enabled & in the future for us to enqueue it */
397 if (alarm->enabled && (rtc_tm_to_ktime(now) <
398 rtc->aie_timer.node.expires)) {
399
400 rtc->aie_timer.enabled = 1;
401 timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
402 }
403 mutex_unlock(&rtc->ops_lock);
404 return err;
405}
406EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
407
408int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
409{
410 int err = mutex_lock_interruptible(&rtc->ops_lock);
411 if (err)
412 return err;
413
414 if (rtc->aie_timer.enabled != enabled) {
415 if (enabled)
416 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
417 else
418 rtc_timer_remove(rtc, &rtc->aie_timer);
419 }
420
421 if (err)
422 /* nothing */;
423 else if (!rtc->ops)
424 err = -ENODEV;
425 else if (!rtc->ops->alarm_irq_enable)
426 err = -EINVAL;
427 else
428 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
429
430 mutex_unlock(&rtc->ops_lock);
431 return err;
432}
433EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
434
435int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
436{
437 int err = mutex_lock_interruptible(&rtc->ops_lock);
438 if (err)
439 return err;
440
441#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
442 if (enabled == 0 && rtc->uie_irq_active) {
443 mutex_unlock(&rtc->ops_lock);
444 return rtc_dev_update_irq_enable_emul(rtc, 0);
445 }
446#endif
447 /* make sure we're changing state */
448 if (rtc->uie_rtctimer.enabled == enabled)
449 goto out;
450
451 if (rtc->uie_unsupported) {
452 err = -EINVAL;
453 goto out;
454 }
455
456 if (enabled) {
457 struct rtc_time tm;
458 ktime_t now, onesec;
459
460 __rtc_read_time(rtc, &tm);
461 onesec = ktime_set(1, 0);
462 now = rtc_tm_to_ktime(tm);
463 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
464 rtc->uie_rtctimer.period = ktime_set(1, 0);
465 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
466 } else
467 rtc_timer_remove(rtc, &rtc->uie_rtctimer);
468
469out:
470 mutex_unlock(&rtc->ops_lock);
471#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
472 /*
473 * Enable emulation if the driver did not provide
474 * the update_irq_enable function pointer or if returned
475 * -EINVAL to signal that it has been configured without
476 * interrupts or that are not available at the moment.
477 */
478 if (err == -EINVAL)
479 err = rtc_dev_update_irq_enable_emul(rtc, enabled);
480#endif
481 return err;
482
483}
484EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
485
486
487/**
488 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
489 * @rtc: pointer to the rtc device
490 *
491 * This function is called when an AIE, UIE or PIE mode interrupt
492 * has occurred (or been emulated).
493 *
494 * Triggers the registered irq_task function callback.
495 */
496void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
497{
498 unsigned long flags;
499
500 /* mark one irq of the appropriate mode */
501 spin_lock_irqsave(&rtc->irq_lock, flags);
502 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF|mode);
503 spin_unlock_irqrestore(&rtc->irq_lock, flags);
504
505 /* call the task func */
506 spin_lock_irqsave(&rtc->irq_task_lock, flags);
507 if (rtc->irq_task)
508 rtc->irq_task->func(rtc->irq_task->private_data);
509 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
510
511 wake_up_interruptible(&rtc->irq_queue);
512 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
513}
514
515
516/**
517 * rtc_aie_update_irq - AIE mode rtctimer hook
518 * @private: pointer to the rtc_device
519 *
520 * This functions is called when the aie_timer expires.
521 */
522void rtc_aie_update_irq(void *private)
523{
524 struct rtc_device *rtc = (struct rtc_device *)private;
525 rtc_handle_legacy_irq(rtc, 1, RTC_AF);
526}
527
528
529/**
530 * rtc_uie_update_irq - UIE mode rtctimer hook
531 * @private: pointer to the rtc_device
532 *
533 * This functions is called when the uie_timer expires.
534 */
535void rtc_uie_update_irq(void *private)
536{
537 struct rtc_device *rtc = (struct rtc_device *)private;
538 rtc_handle_legacy_irq(rtc, 1, RTC_UF);
539}
540
541
542/**
543 * rtc_pie_update_irq - PIE mode hrtimer hook
544 * @timer: pointer to the pie mode hrtimer
545 *
546 * This function is used to emulate PIE mode interrupts
547 * using an hrtimer. This function is called when the periodic
548 * hrtimer expires.
549 */
550enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
551{
552 struct rtc_device *rtc;
553 ktime_t period;
554 int count;
555 rtc = container_of(timer, struct rtc_device, pie_timer);
556
557 period = NSEC_PER_SEC / rtc->irq_freq;
558 count = hrtimer_forward_now(timer, period);
559
560 rtc_handle_legacy_irq(rtc, count, RTC_PF);
561
562 return HRTIMER_RESTART;
563}
564
565/**
566 * rtc_update_irq - Triggered when a RTC interrupt occurs.
567 * @rtc: the rtc device
568 * @num: how many irqs are being reported (usually one)
569 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
570 * Context: any
571 */
572void rtc_update_irq(struct rtc_device *rtc,
573 unsigned long num, unsigned long events)
574{
575 if (IS_ERR_OR_NULL(rtc))
576 return;
577
578 pm_stay_awake(rtc->dev.parent);
579 schedule_work(&rtc->irqwork);
580}
581EXPORT_SYMBOL_GPL(rtc_update_irq);
582
583static int __rtc_match(struct device *dev, const void *data)
584{
585 const char *name = data;
586
587 if (strcmp(dev_name(dev), name) == 0)
588 return 1;
589 return 0;
590}
591
592struct rtc_device *rtc_class_open(const char *name)
593{
594 struct device *dev;
595 struct rtc_device *rtc = NULL;
596
597 dev = class_find_device(rtc_class, NULL, name, __rtc_match);
598 if (dev)
599 rtc = to_rtc_device(dev);
600
601 if (rtc) {
602 if (!try_module_get(rtc->owner)) {
603 put_device(dev);
604 rtc = NULL;
605 }
606 }
607
608 return rtc;
609}
610EXPORT_SYMBOL_GPL(rtc_class_open);
611
612void rtc_class_close(struct rtc_device *rtc)
613{
614 module_put(rtc->owner);
615 put_device(&rtc->dev);
616}
617EXPORT_SYMBOL_GPL(rtc_class_close);
618
619int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
620{
621 int retval = -EBUSY;
622
623 if (task == NULL || task->func == NULL)
624 return -EINVAL;
625
626 /* Cannot register while the char dev is in use */
627 if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
628 return -EBUSY;
629
630 spin_lock_irq(&rtc->irq_task_lock);
631 if (rtc->irq_task == NULL) {
632 rtc->irq_task = task;
633 retval = 0;
634 }
635 spin_unlock_irq(&rtc->irq_task_lock);
636
637 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
638
639 return retval;
640}
641EXPORT_SYMBOL_GPL(rtc_irq_register);
642
643void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task)
644{
645 spin_lock_irq(&rtc->irq_task_lock);
646 if (rtc->irq_task == task)
647 rtc->irq_task = NULL;
648 spin_unlock_irq(&rtc->irq_task_lock);
649}
650EXPORT_SYMBOL_GPL(rtc_irq_unregister);
651
652static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
653{
654 /*
655 * We always cancel the timer here first, because otherwise
656 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
657 * when we manage to start the timer before the callback
658 * returns HRTIMER_RESTART.
659 *
660 * We cannot use hrtimer_cancel() here as a running callback
661 * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
662 * would spin forever.
663 */
664 if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
665 return -1;
666
667 if (enabled) {
668 ktime_t period = NSEC_PER_SEC / rtc->irq_freq;
669
670 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
671 }
672 return 0;
673}
674
675/**
676 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
677 * @rtc: the rtc device
678 * @task: currently registered with rtc_irq_register()
679 * @enabled: true to enable periodic IRQs
680 * Context: any
681 *
682 * Note that rtc_irq_set_freq() should previously have been used to
683 * specify the desired frequency of periodic IRQ task->func() callbacks.
684 */
685int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled)
686{
687 int err = 0;
688 unsigned long flags;
689
690retry:
691 spin_lock_irqsave(&rtc->irq_task_lock, flags);
692 if (rtc->irq_task != NULL && task == NULL)
693 err = -EBUSY;
694 else if (rtc->irq_task != task)
695 err = -EACCES;
696 else {
697 if (rtc_update_hrtimer(rtc, enabled) < 0) {
698 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
699 cpu_relax();
700 goto retry;
701 }
702 rtc->pie_enabled = enabled;
703 }
704 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
705 return err;
706}
707EXPORT_SYMBOL_GPL(rtc_irq_set_state);
708
709/**
710 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
711 * @rtc: the rtc device
712 * @task: currently registered with rtc_irq_register()
713 * @freq: positive frequency with which task->func() will be called
714 * Context: any
715 *
716 * Note that rtc_irq_set_state() is used to enable or disable the
717 * periodic IRQs.
718 */
719int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
720{
721 int err = 0;
722 unsigned long flags;
723
724 if (freq <= 0 || freq > RTC_MAX_FREQ)
725 return -EINVAL;
726retry:
727 spin_lock_irqsave(&rtc->irq_task_lock, flags);
728 if (rtc->irq_task != NULL && task == NULL)
729 err = -EBUSY;
730 else if (rtc->irq_task != task)
731 err = -EACCES;
732 else {
733 rtc->irq_freq = freq;
734 if (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0) {
735 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
736 cpu_relax();
737 goto retry;
738 }
739 }
740 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
741 return err;
742}
743EXPORT_SYMBOL_GPL(rtc_irq_set_freq);
744
745/**
746 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
747 * @rtc rtc device
748 * @timer timer being added.
749 *
750 * Enqueues a timer onto the rtc devices timerqueue and sets
751 * the next alarm event appropriately.
752 *
753 * Sets the enabled bit on the added timer.
754 *
755 * Must hold ops_lock for proper serialization of timerqueue
756 */
757static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
758{
759 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
760 struct rtc_time tm;
761 ktime_t now;
762
763 timer->enabled = 1;
764 __rtc_read_time(rtc, &tm);
765 now = rtc_tm_to_ktime(tm);
766
767 /* Skip over expired timers */
768 while (next) {
769 if (next->expires >= now)
770 break;
771 next = timerqueue_iterate_next(next);
772 }
773
774 timerqueue_add(&rtc->timerqueue, &timer->node);
775 if (!next) {
776 struct rtc_wkalrm alarm;
777 int err;
778 alarm.time = rtc_ktime_to_tm(timer->node.expires);
779 alarm.enabled = 1;
780 err = __rtc_set_alarm(rtc, &alarm);
781 if (err == -ETIME) {
782 pm_stay_awake(rtc->dev.parent);
783 schedule_work(&rtc->irqwork);
784 } else if (err) {
785 timerqueue_del(&rtc->timerqueue, &timer->node);
786 timer->enabled = 0;
787 return err;
788 }
789 }
790 return 0;
791}
792
793static void rtc_alarm_disable(struct rtc_device *rtc)
794{
795 if (!rtc->ops || !rtc->ops->alarm_irq_enable)
796 return;
797
798 rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
799}
800
801/**
802 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
803 * @rtc rtc device
804 * @timer timer being removed.
805 *
806 * Removes a timer onto the rtc devices timerqueue and sets
807 * the next alarm event appropriately.
808 *
809 * Clears the enabled bit on the removed timer.
810 *
811 * Must hold ops_lock for proper serialization of timerqueue
812 */
813static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
814{
815 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
816 timerqueue_del(&rtc->timerqueue, &timer->node);
817 timer->enabled = 0;
818 if (next == &timer->node) {
819 struct rtc_wkalrm alarm;
820 int err;
821 next = timerqueue_getnext(&rtc->timerqueue);
822 if (!next) {
823 rtc_alarm_disable(rtc);
824 return;
825 }
826 alarm.time = rtc_ktime_to_tm(next->expires);
827 alarm.enabled = 1;
828 err = __rtc_set_alarm(rtc, &alarm);
829 if (err == -ETIME) {
830 pm_stay_awake(rtc->dev.parent);
831 schedule_work(&rtc->irqwork);
832 }
833 }
834}
835
836/**
837 * rtc_timer_do_work - Expires rtc timers
838 * @rtc rtc device
839 * @timer timer being removed.
840 *
841 * Expires rtc timers. Reprograms next alarm event if needed.
842 * Called via worktask.
843 *
844 * Serializes access to timerqueue via ops_lock mutex
845 */
846void rtc_timer_do_work(struct work_struct *work)
847{
848 struct rtc_timer *timer;
849 struct timerqueue_node *next;
850 ktime_t now;
851 struct rtc_time tm;
852
853 struct rtc_device *rtc =
854 container_of(work, struct rtc_device, irqwork);
855
856 mutex_lock(&rtc->ops_lock);
857again:
858 __rtc_read_time(rtc, &tm);
859 now = rtc_tm_to_ktime(tm);
860 while ((next = timerqueue_getnext(&rtc->timerqueue))) {
861 if (next->expires > now)
862 break;
863
864 /* expire timer */
865 timer = container_of(next, struct rtc_timer, node);
866 timerqueue_del(&rtc->timerqueue, &timer->node);
867 timer->enabled = 0;
868 if (timer->task.func)
869 timer->task.func(timer->task.private_data);
870
871 /* Re-add/fwd periodic timers */
872 if (ktime_to_ns(timer->period)) {
873 timer->node.expires = ktime_add(timer->node.expires,
874 timer->period);
875 timer->enabled = 1;
876 timerqueue_add(&rtc->timerqueue, &timer->node);
877 }
878 }
879
880 /* Set next alarm */
881 if (next) {
882 struct rtc_wkalrm alarm;
883 int err;
884 int retry = 3;
885
886 alarm.time = rtc_ktime_to_tm(next->expires);
887 alarm.enabled = 1;
888reprogram:
889 err = __rtc_set_alarm(rtc, &alarm);
890 if (err == -ETIME)
891 goto again;
892 else if (err) {
893 if (retry-- > 0)
894 goto reprogram;
895
896 timer = container_of(next, struct rtc_timer, node);
897 timerqueue_del(&rtc->timerqueue, &timer->node);
898 timer->enabled = 0;
899 dev_err(&rtc->dev, "__rtc_set_alarm: err=%d\n", err);
900 goto again;
901 }
902 } else
903 rtc_alarm_disable(rtc);
904
905 pm_relax(rtc->dev.parent);
906 mutex_unlock(&rtc->ops_lock);
907}
908
909
910/* rtc_timer_init - Initializes an rtc_timer
911 * @timer: timer to be intiialized
912 * @f: function pointer to be called when timer fires
913 * @data: private data passed to function pointer
914 *
915 * Kernel interface to initializing an rtc_timer.
916 */
917void rtc_timer_init(struct rtc_timer *timer, void (*f)(void *p), void *data)
918{
919 timerqueue_init(&timer->node);
920 timer->enabled = 0;
921 timer->task.func = f;
922 timer->task.private_data = data;
923}
924
925/* rtc_timer_start - Sets an rtc_timer to fire in the future
926 * @ rtc: rtc device to be used
927 * @ timer: timer being set
928 * @ expires: time at which to expire the timer
929 * @ period: period that the timer will recur
930 *
931 * Kernel interface to set an rtc_timer
932 */
933int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
934 ktime_t expires, ktime_t period)
935{
936 int ret = 0;
937 mutex_lock(&rtc->ops_lock);
938 if (timer->enabled)
939 rtc_timer_remove(rtc, timer);
940
941 timer->node.expires = expires;
942 timer->period = period;
943
944 ret = rtc_timer_enqueue(rtc, timer);
945
946 mutex_unlock(&rtc->ops_lock);
947 return ret;
948}
949
950/* rtc_timer_cancel - Stops an rtc_timer
951 * @ rtc: rtc device to be used
952 * @ timer: timer being set
953 *
954 * Kernel interface to cancel an rtc_timer
955 */
956void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
957{
958 mutex_lock(&rtc->ops_lock);
959 if (timer->enabled)
960 rtc_timer_remove(rtc, timer);
961 mutex_unlock(&rtc->ops_lock);
962}
963
964/**
965 * rtc_read_offset - Read the amount of rtc offset in parts per billion
966 * @ rtc: rtc device to be used
967 * @ offset: the offset in parts per billion
968 *
969 * see below for details.
970 *
971 * Kernel interface to read rtc clock offset
972 * Returns 0 on success, or a negative number on error.
973 * If read_offset() is not implemented for the rtc, return -EINVAL
974 */
975int rtc_read_offset(struct rtc_device *rtc, long *offset)
976{
977 int ret;
978
979 if (!rtc->ops)
980 return -ENODEV;
981
982 if (!rtc->ops->read_offset)
983 return -EINVAL;
984
985 mutex_lock(&rtc->ops_lock);
986 ret = rtc->ops->read_offset(rtc->dev.parent, offset);
987 mutex_unlock(&rtc->ops_lock);
988 return ret;
989}
990
991/**
992 * rtc_set_offset - Adjusts the duration of the average second
993 * @ rtc: rtc device to be used
994 * @ offset: the offset in parts per billion
995 *
996 * Some rtc's allow an adjustment to the average duration of a second
997 * to compensate for differences in the actual clock rate due to temperature,
998 * the crystal, capacitor, etc.
999 *
1000 * Kernel interface to adjust an rtc clock offset.
1001 * Return 0 on success, or a negative number on error.
1002 * If the rtc offset is not setable (or not implemented), return -EINVAL
1003 */
1004int rtc_set_offset(struct rtc_device *rtc, long offset)
1005{
1006 int ret;
1007
1008 if (!rtc->ops)
1009 return -ENODEV;
1010
1011 if (!rtc->ops->set_offset)
1012 return -EINVAL;
1013
1014 mutex_lock(&rtc->ops_lock);
1015 ret = rtc->ops->set_offset(rtc->dev.parent, offset);
1016 mutex_unlock(&rtc->ops_lock);
1017 return ret;
1018}