Line data Source code
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 :
20 : static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer);
21 : static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer);
22 :
23 0 : static void rtc_add_offset(struct rtc_device *rtc, struct rtc_time *tm)
24 : {
25 0 : time64_t secs;
26 :
27 0 : if (!rtc->offset_secs)
28 : return;
29 :
30 0 : 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 0 : if ((rtc->start_secs > rtc->range_min && secs >= rtc->start_secs) ||
39 0 : (rtc->start_secs < rtc->range_min &&
40 0 : secs <= (rtc->start_secs + rtc->range_max - rtc->range_min)))
41 : return;
42 :
43 0 : rtc_time64_to_tm(secs + rtc->offset_secs, tm);
44 : }
45 :
46 0 : static void rtc_subtract_offset(struct rtc_device *rtc, struct rtc_time *tm)
47 : {
48 0 : time64_t secs;
49 :
50 0 : if (!rtc->offset_secs)
51 : return;
52 :
53 0 : 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 0 : if (secs >= rtc->range_min && secs <= rtc->range_max)
62 : return;
63 :
64 0 : rtc_time64_to_tm(secs - rtc->offset_secs, tm);
65 : }
66 :
67 0 : static int rtc_valid_range(struct rtc_device *rtc, struct rtc_time *tm)
68 : {
69 0 : if (rtc->range_min != rtc->range_max) {
70 0 : time64_t time = rtc_tm_to_time64(tm);
71 0 : time64_t range_min = rtc->set_start_time ? rtc->start_secs :
72 : rtc->range_min;
73 0 : timeu64_t range_max = rtc->set_start_time ?
74 0 : (rtc->start_secs + rtc->range_max - rtc->range_min) :
75 : rtc->range_max;
76 :
77 0 : if (time < range_min || time > range_max)
78 0 : return -ERANGE;
79 : }
80 :
81 : return 0;
82 : }
83 :
84 0 : static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
85 : {
86 0 : int err;
87 :
88 0 : if (!rtc->ops) {
89 : err = -ENODEV;
90 0 : } else if (!rtc->ops->read_time) {
91 : err = -EINVAL;
92 : } else {
93 0 : memset(tm, 0, sizeof(struct rtc_time));
94 0 : err = rtc->ops->read_time(rtc->dev.parent, tm);
95 0 : if (err < 0) {
96 : dev_dbg(&rtc->dev, "read_time: fail to read: %d\n",
97 : err);
98 : return err;
99 : }
100 :
101 0 : rtc_add_offset(rtc, tm);
102 :
103 0 : err = rtc_valid_tm(tm);
104 0 : if (err < 0)
105 : dev_dbg(&rtc->dev, "read_time: rtc_time isn't valid\n");
106 : }
107 : return err;
108 : }
109 :
110 0 : int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
111 : {
112 0 : int err;
113 :
114 0 : err = mutex_lock_interruptible(&rtc->ops_lock);
115 0 : if (err)
116 : return err;
117 :
118 0 : err = __rtc_read_time(rtc, tm);
119 0 : mutex_unlock(&rtc->ops_lock);
120 :
121 0 : trace_rtc_read_time(rtc_tm_to_time64(tm), err);
122 0 : return err;
123 : }
124 : EXPORT_SYMBOL_GPL(rtc_read_time);
125 :
126 0 : int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
127 : {
128 0 : int err, uie;
129 :
130 0 : err = rtc_valid_tm(tm);
131 0 : if (err != 0)
132 : return err;
133 :
134 0 : err = rtc_valid_range(rtc, tm);
135 0 : if (err)
136 : return err;
137 :
138 0 : 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 0 : uie = rtc->uie_rtctimer.enabled;
144 : #endif
145 0 : if (uie) {
146 0 : err = rtc_update_irq_enable(rtc, 0);
147 0 : if (err)
148 : return err;
149 : }
150 :
151 0 : err = mutex_lock_interruptible(&rtc->ops_lock);
152 0 : if (err)
153 : return err;
154 :
155 0 : if (!rtc->ops)
156 : err = -ENODEV;
157 0 : else if (rtc->ops->set_time)
158 0 : err = rtc->ops->set_time(rtc->dev.parent, tm);
159 : else
160 : err = -EINVAL;
161 :
162 0 : pm_stay_awake(rtc->dev.parent);
163 0 : mutex_unlock(&rtc->ops_lock);
164 : /* A timer might have just expired */
165 0 : schedule_work(&rtc->irqwork);
166 :
167 0 : if (uie) {
168 0 : err = rtc_update_irq_enable(rtc, 1);
169 0 : if (err)
170 : return err;
171 : }
172 :
173 0 : trace_rtc_set_time(rtc_tm_to_time64(tm), err);
174 0 : return err;
175 : }
176 : EXPORT_SYMBOL_GPL(rtc_set_time);
177 :
178 0 : static int rtc_read_alarm_internal(struct rtc_device *rtc,
179 : struct rtc_wkalrm *alarm)
180 : {
181 0 : int err;
182 :
183 0 : err = mutex_lock_interruptible(&rtc->ops_lock);
184 0 : if (err)
185 : return err;
186 :
187 0 : if (!rtc->ops) {
188 : err = -ENODEV;
189 0 : } else if (!test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->read_alarm) {
190 : err = -EINVAL;
191 : } else {
192 0 : alarm->enabled = 0;
193 0 : alarm->pending = 0;
194 0 : alarm->time.tm_sec = -1;
195 0 : alarm->time.tm_min = -1;
196 0 : alarm->time.tm_hour = -1;
197 0 : alarm->time.tm_mday = -1;
198 0 : alarm->time.tm_mon = -1;
199 0 : alarm->time.tm_year = -1;
200 0 : alarm->time.tm_wday = -1;
201 0 : alarm->time.tm_yday = -1;
202 0 : alarm->time.tm_isdst = -1;
203 0 : err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
204 : }
205 :
206 0 : mutex_unlock(&rtc->ops_lock);
207 :
208 0 : trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
209 0 : return err;
210 : }
211 :
212 0 : int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
213 : {
214 0 : int err;
215 0 : struct rtc_time before, now;
216 0 : int first_time = 1;
217 0 : time64_t t_now, t_alm;
218 0 : enum { none, day, month, year } missing = none;
219 0 : unsigned int days;
220 :
221 : /* The lower level RTC driver may return -1 in some fields,
222 : * creating invalid alarm->time values, for reasons like:
223 : *
224 : * - The hardware may not be capable of filling them in;
225 : * many alarms match only on time-of-day fields, not
226 : * day/month/year calendar data.
227 : *
228 : * - Some hardware uses illegal values as "wildcard" match
229 : * values, which non-Linux firmware (like a BIOS) may try
230 : * to set up as e.g. "alarm 15 minutes after each hour".
231 : * Linux uses only oneshot alarms.
232 : *
233 : * When we see that here, we deal with it by using values from
234 : * a current RTC timestamp for any missing (-1) values. The
235 : * RTC driver prevents "periodic alarm" modes.
236 : *
237 : * But this can be racey, because some fields of the RTC timestamp
238 : * may have wrapped in the interval since we read the RTC alarm,
239 : * which would lead to us inserting inconsistent values in place
240 : * of the -1 fields.
241 : *
242 : * Reading the alarm and timestamp in the reverse sequence
243 : * would have the same race condition, and not solve the issue.
244 : *
245 : * So, we must first read the RTC timestamp,
246 : * then read the RTC alarm value,
247 : * and then read a second RTC timestamp.
248 : *
249 : * If any fields of the second timestamp have changed
250 : * when compared with the first timestamp, then we know
251 : * our timestamp may be inconsistent with that used by
252 : * the low-level rtc_read_alarm_internal() function.
253 : *
254 : * So, when the two timestamps disagree, we just loop and do
255 : * the process again to get a fully consistent set of values.
256 : *
257 : * This could all instead be done in the lower level driver,
258 : * but since more than one lower level RTC implementation needs it,
259 : * then it's probably best best to do it here instead of there..
260 : */
261 :
262 : /* Get the "before" timestamp */
263 0 : err = rtc_read_time(rtc, &before);
264 0 : if (err < 0)
265 : return err;
266 : do {
267 : if (!first_time)
268 0 : memcpy(&before, &now, sizeof(struct rtc_time));
269 0 : first_time = 0;
270 :
271 : /* get the RTC alarm values, which may be incomplete */
272 0 : err = rtc_read_alarm_internal(rtc, alarm);
273 0 : if (err)
274 0 : return err;
275 :
276 : /* full-function RTCs won't have such missing fields */
277 0 : if (rtc_valid_tm(&alarm->time) == 0) {
278 0 : rtc_add_offset(rtc, &alarm->time);
279 0 : return 0;
280 : }
281 :
282 : /* get the "after" timestamp, to detect wrapped fields */
283 0 : err = rtc_read_time(rtc, &now);
284 0 : if (err < 0)
285 0 : return err;
286 :
287 : /* note that tm_sec is a "don't care" value here: */
288 0 : } while (before.tm_min != now.tm_min ||
289 0 : before.tm_hour != now.tm_hour ||
290 0 : before.tm_mon != now.tm_mon ||
291 0 : before.tm_year != now.tm_year);
292 :
293 : /* Fill in the missing alarm fields using the timestamp; we
294 : * know there's at least one since alarm->time is invalid.
295 : */
296 0 : if (alarm->time.tm_sec == -1)
297 0 : alarm->time.tm_sec = now.tm_sec;
298 0 : if (alarm->time.tm_min == -1)
299 0 : alarm->time.tm_min = now.tm_min;
300 0 : if (alarm->time.tm_hour == -1)
301 0 : alarm->time.tm_hour = now.tm_hour;
302 :
303 : /* For simplicity, only support date rollover for now */
304 0 : if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) {
305 0 : alarm->time.tm_mday = now.tm_mday;
306 0 : missing = day;
307 : }
308 0 : if ((unsigned int)alarm->time.tm_mon >= 12) {
309 0 : alarm->time.tm_mon = now.tm_mon;
310 0 : if (missing == none)
311 0 : missing = month;
312 : }
313 0 : if (alarm->time.tm_year == -1) {
314 0 : alarm->time.tm_year = now.tm_year;
315 0 : if (missing == none)
316 0 : missing = year;
317 : }
318 :
319 : /* Can't proceed if alarm is still invalid after replacing
320 : * missing fields.
321 : */
322 0 : err = rtc_valid_tm(&alarm->time);
323 0 : if (err)
324 0 : goto done;
325 :
326 : /* with luck, no rollover is needed */
327 0 : t_now = rtc_tm_to_time64(&now);
328 0 : t_alm = rtc_tm_to_time64(&alarm->time);
329 0 : if (t_now < t_alm)
330 0 : goto done;
331 :
332 0 : switch (missing) {
333 : /* 24 hour rollover ... if it's now 10am Monday, an alarm that
334 : * that will trigger at 5am will do so at 5am Tuesday, which
335 : * could also be in the next month or year. This is a common
336 : * case, especially for PCs.
337 : */
338 : case day:
339 0 : dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
340 0 : t_alm += 24 * 60 * 60;
341 0 : rtc_time64_to_tm(t_alm, &alarm->time);
342 0 : break;
343 :
344 : /* Month rollover ... if it's the 31th, an alarm on the 3rd will
345 : * be next month. An alarm matching on the 30th, 29th, or 28th
346 : * may end up in the month after that! Many newer PCs support
347 : * this type of alarm.
348 : */
349 : case month:
350 : dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
351 0 : do {
352 0 : if (alarm->time.tm_mon < 11) {
353 0 : alarm->time.tm_mon++;
354 : } else {
355 0 : alarm->time.tm_mon = 0;
356 0 : alarm->time.tm_year++;
357 : }
358 0 : days = rtc_month_days(alarm->time.tm_mon,
359 0 : alarm->time.tm_year);
360 0 : } while (days < alarm->time.tm_mday);
361 : break;
362 :
363 : /* Year rollover ... easy except for leap years! */
364 : case year:
365 : dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
366 0 : do {
367 0 : alarm->time.tm_year++;
368 0 : } while (!is_leap_year(alarm->time.tm_year + 1900) &&
369 0 : rtc_valid_tm(&alarm->time) != 0);
370 : break;
371 :
372 0 : default:
373 0 : dev_warn(&rtc->dev, "alarm rollover not handled\n");
374 : }
375 :
376 0 : err = rtc_valid_tm(&alarm->time);
377 :
378 0 : done:
379 0 : if (err)
380 0 : dev_warn(&rtc->dev, "invalid alarm value: %ptR\n",
381 : &alarm->time);
382 :
383 : return err;
384 : }
385 :
386 0 : int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
387 : {
388 0 : int err;
389 :
390 0 : err = mutex_lock_interruptible(&rtc->ops_lock);
391 0 : if (err)
392 : return err;
393 0 : if (!rtc->ops) {
394 : err = -ENODEV;
395 0 : } else if (!test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->read_alarm) {
396 : err = -EINVAL;
397 : } else {
398 0 : memset(alarm, 0, sizeof(struct rtc_wkalrm));
399 0 : alarm->enabled = rtc->aie_timer.enabled;
400 0 : alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
401 : }
402 0 : mutex_unlock(&rtc->ops_lock);
403 :
404 0 : trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
405 0 : return err;
406 : }
407 : EXPORT_SYMBOL_GPL(rtc_read_alarm);
408 :
409 0 : static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
410 : {
411 0 : struct rtc_time tm;
412 0 : time64_t now, scheduled;
413 0 : int err;
414 :
415 0 : err = rtc_valid_tm(&alarm->time);
416 0 : if (err)
417 : return err;
418 :
419 0 : scheduled = rtc_tm_to_time64(&alarm->time);
420 :
421 : /* Make sure we're not setting alarms in the past */
422 0 : err = __rtc_read_time(rtc, &tm);
423 0 : if (err)
424 : return err;
425 0 : now = rtc_tm_to_time64(&tm);
426 0 : if (scheduled <= now)
427 : return -ETIME;
428 : /*
429 : * XXX - We just checked to make sure the alarm time is not
430 : * in the past, but there is still a race window where if
431 : * the is alarm set for the next second and the second ticks
432 : * over right here, before we set the alarm.
433 : */
434 :
435 0 : rtc_subtract_offset(rtc, &alarm->time);
436 :
437 0 : if (!rtc->ops)
438 : err = -ENODEV;
439 0 : else if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
440 : err = -EINVAL;
441 : else
442 0 : err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
443 :
444 0 : trace_rtc_set_alarm(rtc_tm_to_time64(&alarm->time), err);
445 0 : return err;
446 : }
447 :
448 0 : int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
449 : {
450 0 : int err;
451 :
452 0 : if (!rtc->ops)
453 : return -ENODEV;
454 0 : else if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
455 : return -EINVAL;
456 :
457 0 : err = rtc_valid_tm(&alarm->time);
458 0 : if (err != 0)
459 : return err;
460 :
461 0 : err = rtc_valid_range(rtc, &alarm->time);
462 0 : if (err)
463 : return err;
464 :
465 0 : err = mutex_lock_interruptible(&rtc->ops_lock);
466 0 : if (err)
467 : return err;
468 0 : if (rtc->aie_timer.enabled)
469 0 : rtc_timer_remove(rtc, &rtc->aie_timer);
470 :
471 0 : rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
472 0 : rtc->aie_timer.period = 0;
473 0 : if (alarm->enabled)
474 0 : err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
475 :
476 0 : mutex_unlock(&rtc->ops_lock);
477 :
478 0 : return err;
479 : }
480 : EXPORT_SYMBOL_GPL(rtc_set_alarm);
481 :
482 : /* Called once per device from rtc_device_register */
483 0 : int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
484 : {
485 0 : int err;
486 0 : struct rtc_time now;
487 :
488 0 : err = rtc_valid_tm(&alarm->time);
489 0 : if (err != 0)
490 : return err;
491 :
492 0 : err = rtc_read_time(rtc, &now);
493 0 : if (err)
494 : return err;
495 :
496 0 : err = mutex_lock_interruptible(&rtc->ops_lock);
497 0 : if (err)
498 : return err;
499 :
500 0 : rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
501 0 : rtc->aie_timer.period = 0;
502 :
503 : /* Alarm has to be enabled & in the future for us to enqueue it */
504 0 : if (alarm->enabled && (rtc_tm_to_ktime(now) <
505 0 : rtc->aie_timer.node.expires)) {
506 0 : rtc->aie_timer.enabled = 1;
507 0 : timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
508 0 : trace_rtc_timer_enqueue(&rtc->aie_timer);
509 : }
510 0 : mutex_unlock(&rtc->ops_lock);
511 0 : return err;
512 : }
513 : EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
514 :
515 0 : int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
516 : {
517 0 : int err;
518 :
519 0 : err = mutex_lock_interruptible(&rtc->ops_lock);
520 0 : if (err)
521 : return err;
522 :
523 0 : if (rtc->aie_timer.enabled != enabled) {
524 0 : if (enabled)
525 0 : err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
526 : else
527 0 : rtc_timer_remove(rtc, &rtc->aie_timer);
528 : }
529 :
530 0 : if (err)
531 : /* nothing */;
532 0 : else if (!rtc->ops)
533 : err = -ENODEV;
534 0 : else if (!test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->alarm_irq_enable)
535 : err = -EINVAL;
536 : else
537 0 : err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
538 :
539 0 : mutex_unlock(&rtc->ops_lock);
540 :
541 0 : trace_rtc_alarm_irq_enable(enabled, err);
542 0 : return err;
543 : }
544 : EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
545 :
546 0 : int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
547 : {
548 0 : int rc = 0, err;
549 :
550 0 : err = mutex_lock_interruptible(&rtc->ops_lock);
551 0 : if (err)
552 : return err;
553 :
554 : #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
555 : if (enabled == 0 && rtc->uie_irq_active) {
556 : mutex_unlock(&rtc->ops_lock);
557 : return rtc_dev_update_irq_enable_emul(rtc, 0);
558 : }
559 : #endif
560 : /* make sure we're changing state */
561 0 : if (rtc->uie_rtctimer.enabled == enabled)
562 0 : goto out;
563 :
564 0 : if (rtc->uie_unsupported) {
565 0 : err = -EINVAL;
566 0 : goto out;
567 : }
568 :
569 0 : if (enabled) {
570 0 : struct rtc_time tm;
571 0 : ktime_t now, onesec;
572 :
573 0 : rc = __rtc_read_time(rtc, &tm);
574 0 : if (rc)
575 0 : goto out;
576 0 : onesec = ktime_set(1, 0);
577 0 : now = rtc_tm_to_ktime(tm);
578 0 : rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
579 0 : rtc->uie_rtctimer.period = ktime_set(1, 0);
580 0 : err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
581 : } else {
582 0 : rtc_timer_remove(rtc, &rtc->uie_rtctimer);
583 : }
584 :
585 0 : out:
586 0 : mutex_unlock(&rtc->ops_lock);
587 :
588 : /*
589 : * __rtc_read_time() failed, this probably means that the RTC time has
590 : * never been set or less probably there is a transient error on the
591 : * bus. In any case, avoid enabling emulation has this will fail when
592 : * reading the time too.
593 : */
594 0 : if (rc)
595 0 : return rc;
596 :
597 : #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
598 : /*
599 : * Enable emulation if the driver returned -EINVAL to signal that it has
600 : * been configured without interrupts or they are not available at the
601 : * moment.
602 : */
603 : if (err == -EINVAL)
604 : err = rtc_dev_update_irq_enable_emul(rtc, enabled);
605 : #endif
606 : return err;
607 : }
608 : EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
609 :
610 : /**
611 : * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
612 : * @rtc: pointer to the rtc device
613 : * @num: number of occurence of the event
614 : * @mode: type of the event, RTC_AF, RTC_UF of RTC_PF
615 : *
616 : * This function is called when an AIE, UIE or PIE mode interrupt
617 : * has occurred (or been emulated).
618 : *
619 : */
620 0 : void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
621 : {
622 0 : unsigned long flags;
623 :
624 : /* mark one irq of the appropriate mode */
625 0 : spin_lock_irqsave(&rtc->irq_lock, flags);
626 0 : rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF | mode);
627 0 : spin_unlock_irqrestore(&rtc->irq_lock, flags);
628 :
629 0 : wake_up_interruptible(&rtc->irq_queue);
630 0 : kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
631 0 : }
632 :
633 : /**
634 : * rtc_aie_update_irq - AIE mode rtctimer hook
635 : * @rtc: pointer to the rtc_device
636 : *
637 : * This functions is called when the aie_timer expires.
638 : */
639 0 : void rtc_aie_update_irq(struct rtc_device *rtc)
640 : {
641 0 : rtc_handle_legacy_irq(rtc, 1, RTC_AF);
642 0 : }
643 :
644 : /**
645 : * rtc_uie_update_irq - UIE mode rtctimer hook
646 : * @rtc: pointer to the rtc_device
647 : *
648 : * This functions is called when the uie_timer expires.
649 : */
650 0 : void rtc_uie_update_irq(struct rtc_device *rtc)
651 : {
652 0 : rtc_handle_legacy_irq(rtc, 1, RTC_UF);
653 0 : }
654 :
655 : /**
656 : * rtc_pie_update_irq - PIE mode hrtimer hook
657 : * @timer: pointer to the pie mode hrtimer
658 : *
659 : * This function is used to emulate PIE mode interrupts
660 : * using an hrtimer. This function is called when the periodic
661 : * hrtimer expires.
662 : */
663 0 : enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
664 : {
665 0 : struct rtc_device *rtc;
666 0 : ktime_t period;
667 0 : u64 count;
668 :
669 0 : rtc = container_of(timer, struct rtc_device, pie_timer);
670 :
671 0 : period = NSEC_PER_SEC / rtc->irq_freq;
672 0 : count = hrtimer_forward_now(timer, period);
673 :
674 0 : rtc_handle_legacy_irq(rtc, count, RTC_PF);
675 :
676 0 : return HRTIMER_RESTART;
677 : }
678 :
679 : /**
680 : * rtc_update_irq - Triggered when a RTC interrupt occurs.
681 : * @rtc: the rtc device
682 : * @num: how many irqs are being reported (usually one)
683 : * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
684 : * Context: any
685 : */
686 0 : void rtc_update_irq(struct rtc_device *rtc,
687 : unsigned long num, unsigned long events)
688 : {
689 0 : if (IS_ERR_OR_NULL(rtc))
690 : return;
691 :
692 0 : pm_stay_awake(rtc->dev.parent);
693 0 : schedule_work(&rtc->irqwork);
694 : }
695 : EXPORT_SYMBOL_GPL(rtc_update_irq);
696 :
697 0 : struct rtc_device *rtc_class_open(const char *name)
698 : {
699 0 : struct device *dev;
700 0 : struct rtc_device *rtc = NULL;
701 :
702 0 : dev = class_find_device_by_name(rtc_class, name);
703 0 : if (dev)
704 0 : rtc = to_rtc_device(dev);
705 :
706 0 : if (rtc) {
707 0 : if (!try_module_get(rtc->owner)) {
708 : put_device(dev);
709 : rtc = NULL;
710 : }
711 : }
712 :
713 0 : return rtc;
714 : }
715 : EXPORT_SYMBOL_GPL(rtc_class_open);
716 :
717 0 : void rtc_class_close(struct rtc_device *rtc)
718 : {
719 0 : module_put(rtc->owner);
720 0 : put_device(&rtc->dev);
721 0 : }
722 : EXPORT_SYMBOL_GPL(rtc_class_close);
723 :
724 0 : static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
725 : {
726 : /*
727 : * We always cancel the timer here first, because otherwise
728 : * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
729 : * when we manage to start the timer before the callback
730 : * returns HRTIMER_RESTART.
731 : *
732 : * We cannot use hrtimer_cancel() here as a running callback
733 : * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
734 : * would spin forever.
735 : */
736 0 : if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
737 : return -1;
738 :
739 0 : if (enabled) {
740 0 : ktime_t period = NSEC_PER_SEC / rtc->irq_freq;
741 :
742 0 : hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
743 : }
744 : return 0;
745 : }
746 :
747 : /**
748 : * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
749 : * @rtc: the rtc device
750 : * @enabled: true to enable periodic IRQs
751 : * Context: any
752 : *
753 : * Note that rtc_irq_set_freq() should previously have been used to
754 : * specify the desired frequency of periodic IRQ.
755 : */
756 0 : int rtc_irq_set_state(struct rtc_device *rtc, int enabled)
757 : {
758 0 : int err = 0;
759 :
760 0 : while (rtc_update_hrtimer(rtc, enabled) < 0)
761 0 : cpu_relax();
762 :
763 0 : rtc->pie_enabled = enabled;
764 :
765 0 : trace_rtc_irq_set_state(enabled, err);
766 0 : return err;
767 : }
768 :
769 : /**
770 : * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
771 : * @rtc: the rtc device
772 : * @freq: positive frequency
773 : * Context: any
774 : *
775 : * Note that rtc_irq_set_state() is used to enable or disable the
776 : * periodic IRQs.
777 : */
778 0 : int rtc_irq_set_freq(struct rtc_device *rtc, int freq)
779 : {
780 0 : int err = 0;
781 :
782 0 : if (freq <= 0 || freq > RTC_MAX_FREQ)
783 : return -EINVAL;
784 :
785 0 : rtc->irq_freq = freq;
786 0 : while (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0)
787 0 : cpu_relax();
788 :
789 0 : trace_rtc_irq_set_freq(freq, err);
790 0 : return err;
791 : }
792 :
793 : /**
794 : * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
795 : * @rtc: rtc device
796 : * @timer: timer being added.
797 : *
798 : * Enqueues a timer onto the rtc devices timerqueue and sets
799 : * the next alarm event appropriately.
800 : *
801 : * Sets the enabled bit on the added timer.
802 : *
803 : * Must hold ops_lock for proper serialization of timerqueue
804 : */
805 0 : static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
806 : {
807 0 : struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
808 0 : struct rtc_time tm;
809 0 : ktime_t now;
810 :
811 0 : timer->enabled = 1;
812 0 : __rtc_read_time(rtc, &tm);
813 0 : now = rtc_tm_to_ktime(tm);
814 :
815 : /* Skip over expired timers */
816 0 : while (next) {
817 0 : if (next->expires >= now)
818 : break;
819 0 : next = timerqueue_iterate_next(next);
820 : }
821 :
822 0 : timerqueue_add(&rtc->timerqueue, &timer->node);
823 0 : trace_rtc_timer_enqueue(timer);
824 0 : if (!next || ktime_before(timer->node.expires, next->expires)) {
825 0 : struct rtc_wkalrm alarm;
826 0 : int err;
827 :
828 0 : alarm.time = rtc_ktime_to_tm(timer->node.expires);
829 0 : alarm.enabled = 1;
830 0 : err = __rtc_set_alarm(rtc, &alarm);
831 0 : if (err == -ETIME) {
832 0 : pm_stay_awake(rtc->dev.parent);
833 0 : schedule_work(&rtc->irqwork);
834 0 : } else if (err) {
835 0 : timerqueue_del(&rtc->timerqueue, &timer->node);
836 0 : trace_rtc_timer_dequeue(timer);
837 0 : timer->enabled = 0;
838 0 : return err;
839 : }
840 : }
841 : return 0;
842 : }
843 :
844 0 : static void rtc_alarm_disable(struct rtc_device *rtc)
845 : {
846 0 : if (!rtc->ops || !test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->alarm_irq_enable)
847 0 : return;
848 :
849 0 : rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
850 0 : trace_rtc_alarm_irq_enable(0, 0);
851 : }
852 :
853 : /**
854 : * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
855 : * @rtc: rtc device
856 : * @timer: timer being removed.
857 : *
858 : * Removes a timer onto the rtc devices timerqueue and sets
859 : * the next alarm event appropriately.
860 : *
861 : * Clears the enabled bit on the removed timer.
862 : *
863 : * Must hold ops_lock for proper serialization of timerqueue
864 : */
865 0 : static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
866 : {
867 0 : struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
868 :
869 0 : timerqueue_del(&rtc->timerqueue, &timer->node);
870 0 : trace_rtc_timer_dequeue(timer);
871 0 : timer->enabled = 0;
872 0 : if (next == &timer->node) {
873 0 : struct rtc_wkalrm alarm;
874 0 : int err;
875 :
876 0 : next = timerqueue_getnext(&rtc->timerqueue);
877 0 : if (!next) {
878 0 : rtc_alarm_disable(rtc);
879 0 : return;
880 : }
881 0 : alarm.time = rtc_ktime_to_tm(next->expires);
882 0 : alarm.enabled = 1;
883 0 : err = __rtc_set_alarm(rtc, &alarm);
884 0 : if (err == -ETIME) {
885 0 : pm_stay_awake(rtc->dev.parent);
886 0 : schedule_work(&rtc->irqwork);
887 : }
888 : }
889 : }
890 :
891 : /**
892 : * rtc_timer_do_work - Expires rtc timers
893 : * @work: work item
894 : *
895 : * Expires rtc timers. Reprograms next alarm event if needed.
896 : * Called via worktask.
897 : *
898 : * Serializes access to timerqueue via ops_lock mutex
899 : */
900 0 : void rtc_timer_do_work(struct work_struct *work)
901 : {
902 0 : struct rtc_timer *timer;
903 0 : struct timerqueue_node *next;
904 0 : ktime_t now;
905 0 : struct rtc_time tm;
906 :
907 0 : struct rtc_device *rtc =
908 0 : container_of(work, struct rtc_device, irqwork);
909 :
910 0 : mutex_lock(&rtc->ops_lock);
911 0 : again:
912 0 : __rtc_read_time(rtc, &tm);
913 0 : now = rtc_tm_to_ktime(tm);
914 0 : while ((next = timerqueue_getnext(&rtc->timerqueue))) {
915 0 : if (next->expires > now)
916 : break;
917 :
918 : /* expire timer */
919 0 : timer = container_of(next, struct rtc_timer, node);
920 0 : timerqueue_del(&rtc->timerqueue, &timer->node);
921 0 : trace_rtc_timer_dequeue(timer);
922 0 : timer->enabled = 0;
923 0 : if (timer->func)
924 0 : timer->func(timer->rtc);
925 :
926 0 : trace_rtc_timer_fired(timer);
927 : /* Re-add/fwd periodic timers */
928 0 : if (ktime_to_ns(timer->period)) {
929 0 : timer->node.expires = ktime_add(timer->node.expires,
930 : timer->period);
931 0 : timer->enabled = 1;
932 0 : timerqueue_add(&rtc->timerqueue, &timer->node);
933 0 : trace_rtc_timer_enqueue(timer);
934 : }
935 : }
936 :
937 : /* Set next alarm */
938 0 : if (next) {
939 0 : struct rtc_wkalrm alarm;
940 0 : int err;
941 0 : int retry = 3;
942 :
943 0 : alarm.time = rtc_ktime_to_tm(next->expires);
944 0 : alarm.enabled = 1;
945 0 : reprogram:
946 0 : err = __rtc_set_alarm(rtc, &alarm);
947 0 : if (err == -ETIME) {
948 0 : goto again;
949 0 : } else if (err) {
950 0 : if (retry-- > 0)
951 0 : goto reprogram;
952 :
953 0 : timer = container_of(next, struct rtc_timer, node);
954 0 : timerqueue_del(&rtc->timerqueue, &timer->node);
955 0 : trace_rtc_timer_dequeue(timer);
956 0 : timer->enabled = 0;
957 0 : dev_err(&rtc->dev, "__rtc_set_alarm: err=%d\n", err);
958 0 : goto again;
959 : }
960 : } else {
961 0 : rtc_alarm_disable(rtc);
962 : }
963 :
964 0 : pm_relax(rtc->dev.parent);
965 0 : mutex_unlock(&rtc->ops_lock);
966 0 : }
967 :
968 : /* rtc_timer_init - Initializes an rtc_timer
969 : * @timer: timer to be intiialized
970 : * @f: function pointer to be called when timer fires
971 : * @rtc: pointer to the rtc_device
972 : *
973 : * Kernel interface to initializing an rtc_timer.
974 : */
975 3 : void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
976 : struct rtc_device *rtc)
977 : {
978 3 : timerqueue_init(&timer->node);
979 3 : timer->enabled = 0;
980 3 : timer->func = f;
981 3 : timer->rtc = rtc;
982 3 : }
983 :
984 : /* rtc_timer_start - Sets an rtc_timer to fire in the future
985 : * @ rtc: rtc device to be used
986 : * @ timer: timer being set
987 : * @ expires: time at which to expire the timer
988 : * @ period: period that the timer will recur
989 : *
990 : * Kernel interface to set an rtc_timer
991 : */
992 0 : int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
993 : ktime_t expires, ktime_t period)
994 : {
995 0 : int ret = 0;
996 :
997 0 : mutex_lock(&rtc->ops_lock);
998 0 : if (timer->enabled)
999 0 : rtc_timer_remove(rtc, timer);
1000 :
1001 0 : timer->node.expires = expires;
1002 0 : timer->period = period;
1003 :
1004 0 : ret = rtc_timer_enqueue(rtc, timer);
1005 :
1006 0 : mutex_unlock(&rtc->ops_lock);
1007 0 : return ret;
1008 : }
1009 :
1010 : /* rtc_timer_cancel - Stops an rtc_timer
1011 : * @ rtc: rtc device to be used
1012 : * @ timer: timer being set
1013 : *
1014 : * Kernel interface to cancel an rtc_timer
1015 : */
1016 0 : void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
1017 : {
1018 0 : mutex_lock(&rtc->ops_lock);
1019 0 : if (timer->enabled)
1020 0 : rtc_timer_remove(rtc, timer);
1021 0 : mutex_unlock(&rtc->ops_lock);
1022 0 : }
1023 :
1024 : /**
1025 : * rtc_read_offset - Read the amount of rtc offset in parts per billion
1026 : * @rtc: rtc device to be used
1027 : * @offset: the offset in parts per billion
1028 : *
1029 : * see below for details.
1030 : *
1031 : * Kernel interface to read rtc clock offset
1032 : * Returns 0 on success, or a negative number on error.
1033 : * If read_offset() is not implemented for the rtc, return -EINVAL
1034 : */
1035 0 : int rtc_read_offset(struct rtc_device *rtc, long *offset)
1036 : {
1037 0 : int ret;
1038 :
1039 0 : if (!rtc->ops)
1040 : return -ENODEV;
1041 :
1042 0 : if (!rtc->ops->read_offset)
1043 : return -EINVAL;
1044 :
1045 0 : mutex_lock(&rtc->ops_lock);
1046 0 : ret = rtc->ops->read_offset(rtc->dev.parent, offset);
1047 0 : mutex_unlock(&rtc->ops_lock);
1048 :
1049 0 : trace_rtc_read_offset(*offset, ret);
1050 0 : return ret;
1051 : }
1052 :
1053 : /**
1054 : * rtc_set_offset - Adjusts the duration of the average second
1055 : * @rtc: rtc device to be used
1056 : * @offset: the offset in parts per billion
1057 : *
1058 : * Some rtc's allow an adjustment to the average duration of a second
1059 : * to compensate for differences in the actual clock rate due to temperature,
1060 : * the crystal, capacitor, etc.
1061 : *
1062 : * The adjustment applied is as follows:
1063 : * t = t0 * (1 + offset * 1e-9)
1064 : * where t0 is the measured length of 1 RTC second with offset = 0
1065 : *
1066 : * Kernel interface to adjust an rtc clock offset.
1067 : * Return 0 on success, or a negative number on error.
1068 : * If the rtc offset is not setable (or not implemented), return -EINVAL
1069 : */
1070 0 : int rtc_set_offset(struct rtc_device *rtc, long offset)
1071 : {
1072 0 : int ret;
1073 :
1074 0 : if (!rtc->ops)
1075 : return -ENODEV;
1076 :
1077 0 : if (!rtc->ops->set_offset)
1078 : return -EINVAL;
1079 :
1080 0 : mutex_lock(&rtc->ops_lock);
1081 0 : ret = rtc->ops->set_offset(rtc->dev.parent, offset);
1082 0 : mutex_unlock(&rtc->ops_lock);
1083 :
1084 0 : trace_rtc_set_offset(offset, ret);
1085 0 : return ret;
1086 : }
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