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1 | /* |
2 | * RTC subsystem, interface functions |
3 | * |
4 | * Copyright (C) 2005 Tower Technologies |
5 | * Author: Alessandro Zummo <a.zummo@towertech.it> |
6 | * |
7 | * based on arch/arm/common/rtctime.c |
8 | * |
9 | * This program is free software; you can redistribute it and/or modify |
10 | * it under the terms of the GNU General Public License version 2 as |
11 | * published by the Free Software Foundation. |
12 | */ |
13 | |
14 | #include <linux/rtc.h> |
15 | #include <linux/sched.h> |
16 | #include <linux/module.h> |
17 | #include <linux/log2.h> |
18 | #include <linux/workqueue.h> |
19 | |
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 | static 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 | |
37 | int 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 | } |
49 | EXPORT_SYMBOL_GPL(rtc_read_time); |
50 | |
51 | int 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 | /* A timer might have just expired */ |
77 | schedule_work(&rtc->irqwork); |
78 | return err; |
79 | } |
80 | EXPORT_SYMBOL_GPL(rtc_set_time); |
81 | |
82 | int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs) |
83 | { |
84 | int err; |
85 | |
86 | err = mutex_lock_interruptible(&rtc->ops_lock); |
87 | if (err) |
88 | return err; |
89 | |
90 | if (!rtc->ops) |
91 | err = -ENODEV; |
92 | else if (rtc->ops->set_mmss) |
93 | err = rtc->ops->set_mmss(rtc->dev.parent, secs); |
94 | else if (rtc->ops->read_time && rtc->ops->set_time) { |
95 | struct rtc_time new, old; |
96 | |
97 | err = rtc->ops->read_time(rtc->dev.parent, &old); |
98 | if (err == 0) { |
99 | rtc_time_to_tm(secs, &new); |
100 | |
101 | /* |
102 | * avoid writing when we're going to change the day of |
103 | * the month. We will retry in the next minute. This |
104 | * basically means that if the RTC must not drift |
105 | * by more than 1 minute in 11 minutes. |
106 | */ |
107 | if (!((old.tm_hour == 23 && old.tm_min == 59) || |
108 | (new.tm_hour == 23 && new.tm_min == 59))) |
109 | err = rtc->ops->set_time(rtc->dev.parent, |
110 | &new); |
111 | } |
112 | } |
113 | else |
114 | err = -EINVAL; |
115 | |
116 | mutex_unlock(&rtc->ops_lock); |
117 | /* A timer might have just expired */ |
118 | schedule_work(&rtc->irqwork); |
119 | |
120 | return err; |
121 | } |
122 | EXPORT_SYMBOL_GPL(rtc_set_mmss); |
123 | |
124 | static int rtc_read_alarm_internal(struct rtc_device *rtc, struct rtc_wkalrm *alarm) |
125 | { |
126 | int err; |
127 | |
128 | err = mutex_lock_interruptible(&rtc->ops_lock); |
129 | if (err) |
130 | return err; |
131 | |
132 | if (rtc->ops == NULL) |
133 | err = -ENODEV; |
134 | else if (!rtc->ops->read_alarm) |
135 | err = -EINVAL; |
136 | else { |
137 | memset(alarm, 0, sizeof(struct rtc_wkalrm)); |
138 | err = rtc->ops->read_alarm(rtc->dev.parent, alarm); |
139 | } |
140 | |
141 | mutex_unlock(&rtc->ops_lock); |
142 | return err; |
143 | } |
144 | |
145 | int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) |
146 | { |
147 | int err; |
148 | struct rtc_time before, now; |
149 | int first_time = 1; |
150 | unsigned long t_now, t_alm; |
151 | enum { none, day, month, year } missing = none; |
152 | unsigned days; |
153 | |
154 | /* The lower level RTC driver may return -1 in some fields, |
155 | * creating invalid alarm->time values, for reasons like: |
156 | * |
157 | * - The hardware may not be capable of filling them in; |
158 | * many alarms match only on time-of-day fields, not |
159 | * day/month/year calendar data. |
160 | * |
161 | * - Some hardware uses illegal values as "wildcard" match |
162 | * values, which non-Linux firmware (like a BIOS) may try |
163 | * to set up as e.g. "alarm 15 minutes after each hour". |
164 | * Linux uses only oneshot alarms. |
165 | * |
166 | * When we see that here, we deal with it by using values from |
167 | * a current RTC timestamp for any missing (-1) values. The |
168 | * RTC driver prevents "periodic alarm" modes. |
169 | * |
170 | * But this can be racey, because some fields of the RTC timestamp |
171 | * may have wrapped in the interval since we read the RTC alarm, |
172 | * which would lead to us inserting inconsistent values in place |
173 | * of the -1 fields. |
174 | * |
175 | * Reading the alarm and timestamp in the reverse sequence |
176 | * would have the same race condition, and not solve the issue. |
177 | * |
178 | * So, we must first read the RTC timestamp, |
179 | * then read the RTC alarm value, |
180 | * and then read a second RTC timestamp. |
181 | * |
182 | * If any fields of the second timestamp have changed |
183 | * when compared with the first timestamp, then we know |
184 | * our timestamp may be inconsistent with that used by |
185 | * the low-level rtc_read_alarm_internal() function. |
186 | * |
187 | * So, when the two timestamps disagree, we just loop and do |
188 | * the process again to get a fully consistent set of values. |
189 | * |
190 | * This could all instead be done in the lower level driver, |
191 | * but since more than one lower level RTC implementation needs it, |
192 | * then it's probably best best to do it here instead of there.. |
193 | */ |
194 | |
195 | /* Get the "before" timestamp */ |
196 | err = rtc_read_time(rtc, &before); |
197 | if (err < 0) |
198 | return err; |
199 | do { |
200 | if (!first_time) |
201 | memcpy(&before, &now, sizeof(struct rtc_time)); |
202 | first_time = 0; |
203 | |
204 | /* get the RTC alarm values, which may be incomplete */ |
205 | err = rtc_read_alarm_internal(rtc, alarm); |
206 | if (err) |
207 | return err; |
208 | |
209 | /* full-function RTCs won't have such missing fields */ |
210 | if (rtc_valid_tm(&alarm->time) == 0) |
211 | return 0; |
212 | |
213 | /* get the "after" timestamp, to detect wrapped fields */ |
214 | err = rtc_read_time(rtc, &now); |
215 | if (err < 0) |
216 | return err; |
217 | |
218 | /* note that tm_sec is a "don't care" value here: */ |
219 | } while ( before.tm_min != now.tm_min |
220 | || before.tm_hour != now.tm_hour |
221 | || before.tm_mon != now.tm_mon |
222 | || before.tm_year != now.tm_year); |
223 | |
224 | /* Fill in the missing alarm fields using the timestamp; we |
225 | * know there's at least one since alarm->time is invalid. |
226 | */ |
227 | if (alarm->time.tm_sec == -1) |
228 | alarm->time.tm_sec = now.tm_sec; |
229 | if (alarm->time.tm_min == -1) |
230 | alarm->time.tm_min = now.tm_min; |
231 | if (alarm->time.tm_hour == -1) |
232 | alarm->time.tm_hour = now.tm_hour; |
233 | |
234 | /* For simplicity, only support date rollover for now */ |
235 | if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) { |
236 | alarm->time.tm_mday = now.tm_mday; |
237 | missing = day; |
238 | } |
239 | if ((unsigned)alarm->time.tm_mon >= 12) { |
240 | alarm->time.tm_mon = now.tm_mon; |
241 | if (missing == none) |
242 | missing = month; |
243 | } |
244 | if (alarm->time.tm_year == -1) { |
245 | alarm->time.tm_year = now.tm_year; |
246 | if (missing == none) |
247 | missing = year; |
248 | } |
249 | |
250 | /* with luck, no rollover is needed */ |
251 | rtc_tm_to_time(&now, &t_now); |
252 | rtc_tm_to_time(&alarm->time, &t_alm); |
253 | if (t_now < t_alm) |
254 | goto done; |
255 | |
256 | switch (missing) { |
257 | |
258 | /* 24 hour rollover ... if it's now 10am Monday, an alarm that |
259 | * that will trigger at 5am will do so at 5am Tuesday, which |
260 | * could also be in the next month or year. This is a common |
261 | * case, especially for PCs. |
262 | */ |
263 | case day: |
264 | dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day"); |
265 | t_alm += 24 * 60 * 60; |
266 | rtc_time_to_tm(t_alm, &alarm->time); |
267 | break; |
268 | |
269 | /* Month rollover ... if it's the 31th, an alarm on the 3rd will |
270 | * be next month. An alarm matching on the 30th, 29th, or 28th |
271 | * may end up in the month after that! Many newer PCs support |
272 | * this type of alarm. |
273 | */ |
274 | case month: |
275 | dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month"); |
276 | do { |
277 | if (alarm->time.tm_mon < 11) |
278 | alarm->time.tm_mon++; |
279 | else { |
280 | alarm->time.tm_mon = 0; |
281 | alarm->time.tm_year++; |
282 | } |
283 | days = rtc_month_days(alarm->time.tm_mon, |
284 | alarm->time.tm_year); |
285 | } while (days < alarm->time.tm_mday); |
286 | break; |
287 | |
288 | /* Year rollover ... easy except for leap years! */ |
289 | case year: |
290 | dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year"); |
291 | do { |
292 | alarm->time.tm_year++; |
293 | } while (rtc_valid_tm(&alarm->time) != 0); |
294 | break; |
295 | |
296 | default: |
297 | dev_warn(&rtc->dev, "alarm rollover not handled\n"); |
298 | } |
299 | |
300 | done: |
301 | return 0; |
302 | } |
303 | |
304 | int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) |
305 | { |
306 | int err; |
307 | |
308 | err = mutex_lock_interruptible(&rtc->ops_lock); |
309 | if (err) |
310 | return err; |
311 | if (rtc->ops == NULL) |
312 | err = -ENODEV; |
313 | else if (!rtc->ops->read_alarm) |
314 | err = -EINVAL; |
315 | else { |
316 | memset(alarm, 0, sizeof(struct rtc_wkalrm)); |
317 | alarm->enabled = rtc->aie_timer.enabled; |
318 | alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires); |
319 | } |
320 | mutex_unlock(&rtc->ops_lock); |
321 | |
322 | return err; |
323 | } |
324 | EXPORT_SYMBOL_GPL(rtc_read_alarm); |
325 | |
326 | static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) |
327 | { |
328 | struct rtc_time tm; |
329 | long now, scheduled; |
330 | int err; |
331 | |
332 | err = rtc_valid_tm(&alarm->time); |
333 | if (err) |
334 | return err; |
335 | rtc_tm_to_time(&alarm->time, &scheduled); |
336 | |
337 | /* Make sure we're not setting alarms in the past */ |
338 | err = __rtc_read_time(rtc, &tm); |
339 | rtc_tm_to_time(&tm, &now); |
340 | if (scheduled <= now) |
341 | return -ETIME; |
342 | /* |
343 | * XXX - We just checked to make sure the alarm time is not |
344 | * in the past, but there is still a race window where if |
345 | * the is alarm set for the next second and the second ticks |
346 | * over right here, before we set the alarm. |
347 | */ |
348 | |
349 | if (!rtc->ops) |
350 | err = -ENODEV; |
351 | else if (!rtc->ops->set_alarm) |
352 | err = -EINVAL; |
353 | else |
354 | err = rtc->ops->set_alarm(rtc->dev.parent, alarm); |
355 | |
356 | return err; |
357 | } |
358 | |
359 | int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) |
360 | { |
361 | int err; |
362 | |
363 | err = rtc_valid_tm(&alarm->time); |
364 | if (err != 0) |
365 | return err; |
366 | |
367 | err = mutex_lock_interruptible(&rtc->ops_lock); |
368 | if (err) |
369 | return err; |
370 | if (rtc->aie_timer.enabled) { |
371 | rtc_timer_remove(rtc, &rtc->aie_timer); |
372 | } |
373 | rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time); |
374 | rtc->aie_timer.period = ktime_set(0, 0); |
375 | if (alarm->enabled) { |
376 | err = rtc_timer_enqueue(rtc, &rtc->aie_timer); |
377 | } |
378 | mutex_unlock(&rtc->ops_lock); |
379 | return err; |
380 | } |
381 | EXPORT_SYMBOL_GPL(rtc_set_alarm); |
382 | |
383 | /* Called once per device from rtc_device_register */ |
384 | int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) |
385 | { |
386 | int err; |
387 | struct rtc_time now; |
388 | |
389 | err = rtc_valid_tm(&alarm->time); |
390 | if (err != 0) |
391 | return err; |
392 | |
393 | err = rtc_read_time(rtc, &now); |
394 | if (err) |
395 | return err; |
396 | |
397 | err = mutex_lock_interruptible(&rtc->ops_lock); |
398 | if (err) |
399 | return err; |
400 | |
401 | rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time); |
402 | rtc->aie_timer.period = ktime_set(0, 0); |
403 | |
404 | /* Alarm has to be enabled & in the futrure for us to enqueue it */ |
405 | if (alarm->enabled && (rtc_tm_to_ktime(now).tv64 < |
406 | rtc->aie_timer.node.expires.tv64)) { |
407 | |
408 | rtc->aie_timer.enabled = 1; |
409 | timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node); |
410 | } |
411 | mutex_unlock(&rtc->ops_lock); |
412 | return err; |
413 | } |
414 | EXPORT_SYMBOL_GPL(rtc_initialize_alarm); |
415 | |
416 | |
417 | |
418 | int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled) |
419 | { |
420 | int err = mutex_lock_interruptible(&rtc->ops_lock); |
421 | if (err) |
422 | return err; |
423 | |
424 | if (rtc->aie_timer.enabled != enabled) { |
425 | if (enabled) |
426 | err = rtc_timer_enqueue(rtc, &rtc->aie_timer); |
427 | else |
428 | rtc_timer_remove(rtc, &rtc->aie_timer); |
429 | } |
430 | |
431 | if (err) |
432 | /* nothing */; |
433 | else if (!rtc->ops) |
434 | err = -ENODEV; |
435 | else if (!rtc->ops->alarm_irq_enable) |
436 | err = -EINVAL; |
437 | else |
438 | err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled); |
439 | |
440 | mutex_unlock(&rtc->ops_lock); |
441 | return err; |
442 | } |
443 | EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable); |
444 | |
445 | int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled) |
446 | { |
447 | int err = mutex_lock_interruptible(&rtc->ops_lock); |
448 | if (err) |
449 | return err; |
450 | |
451 | #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL |
452 | if (enabled == 0 && rtc->uie_irq_active) { |
453 | mutex_unlock(&rtc->ops_lock); |
454 | return rtc_dev_update_irq_enable_emul(rtc, 0); |
455 | } |
456 | #endif |
457 | /* make sure we're changing state */ |
458 | if (rtc->uie_rtctimer.enabled == enabled) |
459 | goto out; |
460 | |
461 | if (rtc->uie_unsupported) { |
462 | err = -EINVAL; |
463 | goto out; |
464 | } |
465 | |
466 | if (enabled) { |
467 | struct rtc_time tm; |
468 | ktime_t now, onesec; |
469 | |
470 | __rtc_read_time(rtc, &tm); |
471 | onesec = ktime_set(1, 0); |
472 | now = rtc_tm_to_ktime(tm); |
473 | rtc->uie_rtctimer.node.expires = ktime_add(now, onesec); |
474 | rtc->uie_rtctimer.period = ktime_set(1, 0); |
475 | err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer); |
476 | } else |
477 | rtc_timer_remove(rtc, &rtc->uie_rtctimer); |
478 | |
479 | out: |
480 | mutex_unlock(&rtc->ops_lock); |
481 | #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL |
482 | /* |
483 | * Enable emulation if the driver did not provide |
484 | * the update_irq_enable function pointer or if returned |
485 | * -EINVAL to signal that it has been configured without |
486 | * interrupts or that are not available at the moment. |
487 | */ |
488 | if (err == -EINVAL) |
489 | err = rtc_dev_update_irq_enable_emul(rtc, enabled); |
490 | #endif |
491 | return err; |
492 | |
493 | } |
494 | EXPORT_SYMBOL_GPL(rtc_update_irq_enable); |
495 | |
496 | |
497 | /** |
498 | * rtc_handle_legacy_irq - AIE, UIE and PIE event hook |
499 | * @rtc: pointer to the rtc device |
500 | * |
501 | * This function is called when an AIE, UIE or PIE mode interrupt |
502 | * has occurred (or been emulated). |
503 | * |
504 | * Triggers the registered irq_task function callback. |
505 | */ |
506 | void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode) |
507 | { |
508 | unsigned long flags; |
509 | |
510 | /* mark one irq of the appropriate mode */ |
511 | spin_lock_irqsave(&rtc->irq_lock, flags); |
512 | rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF|mode); |
513 | spin_unlock_irqrestore(&rtc->irq_lock, flags); |
514 | |
515 | /* call the task func */ |
516 | spin_lock_irqsave(&rtc->irq_task_lock, flags); |
517 | if (rtc->irq_task) |
518 | rtc->irq_task->func(rtc->irq_task->private_data); |
519 | spin_unlock_irqrestore(&rtc->irq_task_lock, flags); |
520 | |
521 | wake_up_interruptible(&rtc->irq_queue); |
522 | kill_fasync(&rtc->async_queue, SIGIO, POLL_IN); |
523 | } |
524 | |
525 | |
526 | /** |
527 | * rtc_aie_update_irq - AIE mode rtctimer hook |
528 | * @private: pointer to the rtc_device |
529 | * |
530 | * This functions is called when the aie_timer expires. |
531 | */ |
532 | void rtc_aie_update_irq(void *private) |
533 | { |
534 | struct rtc_device *rtc = (struct rtc_device *)private; |
535 | rtc_handle_legacy_irq(rtc, 1, RTC_AF); |
536 | } |
537 | |
538 | |
539 | /** |
540 | * rtc_uie_update_irq - UIE mode rtctimer hook |
541 | * @private: pointer to the rtc_device |
542 | * |
543 | * This functions is called when the uie_timer expires. |
544 | */ |
545 | void rtc_uie_update_irq(void *private) |
546 | { |
547 | struct rtc_device *rtc = (struct rtc_device *)private; |
548 | rtc_handle_legacy_irq(rtc, 1, RTC_UF); |
549 | } |
550 | |
551 | |
552 | /** |
553 | * rtc_pie_update_irq - PIE mode hrtimer hook |
554 | * @timer: pointer to the pie mode hrtimer |
555 | * |
556 | * This function is used to emulate PIE mode interrupts |
557 | * using an hrtimer. This function is called when the periodic |
558 | * hrtimer expires. |
559 | */ |
560 | enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer) |
561 | { |
562 | struct rtc_device *rtc; |
563 | ktime_t period; |
564 | int count; |
565 | rtc = container_of(timer, struct rtc_device, pie_timer); |
566 | |
567 | period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq); |
568 | count = hrtimer_forward_now(timer, period); |
569 | |
570 | rtc_handle_legacy_irq(rtc, count, RTC_PF); |
571 | |
572 | return HRTIMER_RESTART; |
573 | } |
574 | |
575 | /** |
576 | * rtc_update_irq - Triggered when a RTC interrupt occurs. |
577 | * @rtc: the rtc device |
578 | * @num: how many irqs are being reported (usually one) |
579 | * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF |
580 | * Context: any |
581 | */ |
582 | void rtc_update_irq(struct rtc_device *rtc, |
583 | unsigned long num, unsigned long events) |
584 | { |
585 | pm_stay_awake(rtc->dev.parent); |
586 | schedule_work(&rtc->irqwork); |
587 | } |
588 | EXPORT_SYMBOL_GPL(rtc_update_irq); |
589 | |
590 | static int __rtc_match(struct device *dev, const void *data) |
591 | { |
592 | const char *name = data; |
593 | |
594 | if (strcmp(dev_name(dev), name) == 0) |
595 | return 1; |
596 | return 0; |
597 | } |
598 | |
599 | struct rtc_device *rtc_class_open(const char *name) |
600 | { |
601 | struct device *dev; |
602 | struct rtc_device *rtc = NULL; |
603 | |
604 | dev = class_find_device(rtc_class, NULL, name, __rtc_match); |
605 | if (dev) |
606 | rtc = to_rtc_device(dev); |
607 | |
608 | if (rtc) { |
609 | if (!try_module_get(rtc->owner)) { |
610 | put_device(dev); |
611 | rtc = NULL; |
612 | } |
613 | } |
614 | |
615 | return rtc; |
616 | } |
617 | EXPORT_SYMBOL_GPL(rtc_class_open); |
618 | |
619 | void rtc_class_close(struct rtc_device *rtc) |
620 | { |
621 | module_put(rtc->owner); |
622 | put_device(&rtc->dev); |
623 | } |
624 | EXPORT_SYMBOL_GPL(rtc_class_close); |
625 | |
626 | int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task) |
627 | { |
628 | int retval = -EBUSY; |
629 | |
630 | if (task == NULL || task->func == NULL) |
631 | return -EINVAL; |
632 | |
633 | /* Cannot register while the char dev is in use */ |
634 | if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags)) |
635 | return -EBUSY; |
636 | |
637 | spin_lock_irq(&rtc->irq_task_lock); |
638 | if (rtc->irq_task == NULL) { |
639 | rtc->irq_task = task; |
640 | retval = 0; |
641 | } |
642 | spin_unlock_irq(&rtc->irq_task_lock); |
643 | |
644 | clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags); |
645 | |
646 | return retval; |
647 | } |
648 | EXPORT_SYMBOL_GPL(rtc_irq_register); |
649 | |
650 | void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task) |
651 | { |
652 | spin_lock_irq(&rtc->irq_task_lock); |
653 | if (rtc->irq_task == task) |
654 | rtc->irq_task = NULL; |
655 | spin_unlock_irq(&rtc->irq_task_lock); |
656 | } |
657 | EXPORT_SYMBOL_GPL(rtc_irq_unregister); |
658 | |
659 | static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled) |
660 | { |
661 | /* |
662 | * We always cancel the timer here first, because otherwise |
663 | * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK); |
664 | * when we manage to start the timer before the callback |
665 | * returns HRTIMER_RESTART. |
666 | * |
667 | * We cannot use hrtimer_cancel() here as a running callback |
668 | * could be blocked on rtc->irq_task_lock and hrtimer_cancel() |
669 | * would spin forever. |
670 | */ |
671 | if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0) |
672 | return -1; |
673 | |
674 | if (enabled) { |
675 | ktime_t period = ktime_set(0, NSEC_PER_SEC / rtc->irq_freq); |
676 | |
677 | hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL); |
678 | } |
679 | return 0; |
680 | } |
681 | |
682 | /** |
683 | * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs |
684 | * @rtc: the rtc device |
685 | * @task: currently registered with rtc_irq_register() |
686 | * @enabled: true to enable periodic IRQs |
687 | * Context: any |
688 | * |
689 | * Note that rtc_irq_set_freq() should previously have been used to |
690 | * specify the desired frequency of periodic IRQ task->func() callbacks. |
691 | */ |
692 | int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled) |
693 | { |
694 | int err = 0; |
695 | unsigned long flags; |
696 | |
697 | retry: |
698 | spin_lock_irqsave(&rtc->irq_task_lock, flags); |
699 | if (rtc->irq_task != NULL && task == NULL) |
700 | err = -EBUSY; |
701 | if (rtc->irq_task != task) |
702 | err = -EACCES; |
703 | if (!err) { |
704 | if (rtc_update_hrtimer(rtc, enabled) < 0) { |
705 | spin_unlock_irqrestore(&rtc->irq_task_lock, flags); |
706 | cpu_relax(); |
707 | goto retry; |
708 | } |
709 | rtc->pie_enabled = enabled; |
710 | } |
711 | spin_unlock_irqrestore(&rtc->irq_task_lock, flags); |
712 | return err; |
713 | } |
714 | EXPORT_SYMBOL_GPL(rtc_irq_set_state); |
715 | |
716 | /** |
717 | * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ |
718 | * @rtc: the rtc device |
719 | * @task: currently registered with rtc_irq_register() |
720 | * @freq: positive frequency with which task->func() will be called |
721 | * Context: any |
722 | * |
723 | * Note that rtc_irq_set_state() is used to enable or disable the |
724 | * periodic IRQs. |
725 | */ |
726 | int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq) |
727 | { |
728 | int err = 0; |
729 | unsigned long flags; |
730 | |
731 | if (freq <= 0 || freq > RTC_MAX_FREQ) |
732 | return -EINVAL; |
733 | retry: |
734 | spin_lock_irqsave(&rtc->irq_task_lock, flags); |
735 | if (rtc->irq_task != NULL && task == NULL) |
736 | err = -EBUSY; |
737 | if (rtc->irq_task != task) |
738 | err = -EACCES; |
739 | if (!err) { |
740 | rtc->irq_freq = freq; |
741 | if (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0) { |
742 | spin_unlock_irqrestore(&rtc->irq_task_lock, flags); |
743 | cpu_relax(); |
744 | goto retry; |
745 | } |
746 | } |
747 | spin_unlock_irqrestore(&rtc->irq_task_lock, flags); |
748 | return err; |
749 | } |
750 | EXPORT_SYMBOL_GPL(rtc_irq_set_freq); |
751 | |
752 | /** |
753 | * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue |
754 | * @rtc rtc device |
755 | * @timer timer being added. |
756 | * |
757 | * Enqueues a timer onto the rtc devices timerqueue and sets |
758 | * the next alarm event appropriately. |
759 | * |
760 | * Sets the enabled bit on the added timer. |
761 | * |
762 | * Must hold ops_lock for proper serialization of timerqueue |
763 | */ |
764 | static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer) |
765 | { |
766 | timer->enabled = 1; |
767 | timerqueue_add(&rtc->timerqueue, &timer->node); |
768 | if (&timer->node == timerqueue_getnext(&rtc->timerqueue)) { |
769 | struct rtc_wkalrm alarm; |
770 | int err; |
771 | alarm.time = rtc_ktime_to_tm(timer->node.expires); |
772 | alarm.enabled = 1; |
773 | err = __rtc_set_alarm(rtc, &alarm); |
774 | if (err == -ETIME) |
775 | schedule_work(&rtc->irqwork); |
776 | else if (err) { |
777 | timerqueue_del(&rtc->timerqueue, &timer->node); |
778 | timer->enabled = 0; |
779 | return err; |
780 | } |
781 | } |
782 | return 0; |
783 | } |
784 | |
785 | static void rtc_alarm_disable(struct rtc_device *rtc) |
786 | { |
787 | if (!rtc->ops || !rtc->ops->alarm_irq_enable) |
788 | return; |
789 | |
790 | rtc->ops->alarm_irq_enable(rtc->dev.parent, false); |
791 | } |
792 | |
793 | /** |
794 | * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue |
795 | * @rtc rtc device |
796 | * @timer timer being removed. |
797 | * |
798 | * Removes a timer onto the rtc devices timerqueue and sets |
799 | * the next alarm event appropriately. |
800 | * |
801 | * Clears the enabled bit on the removed timer. |
802 | * |
803 | * Must hold ops_lock for proper serialization of timerqueue |
804 | */ |
805 | static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer) |
806 | { |
807 | struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue); |
808 | timerqueue_del(&rtc->timerqueue, &timer->node); |
809 | timer->enabled = 0; |
810 | if (next == &timer->node) { |
811 | struct rtc_wkalrm alarm; |
812 | int err; |
813 | next = timerqueue_getnext(&rtc->timerqueue); |
814 | if (!next) { |
815 | rtc_alarm_disable(rtc); |
816 | return; |
817 | } |
818 | alarm.time = rtc_ktime_to_tm(next->expires); |
819 | alarm.enabled = 1; |
820 | err = __rtc_set_alarm(rtc, &alarm); |
821 | if (err == -ETIME) |
822 | schedule_work(&rtc->irqwork); |
823 | } |
824 | } |
825 | |
826 | /** |
827 | * rtc_timer_do_work - Expires rtc timers |
828 | * @rtc rtc device |
829 | * @timer timer being removed. |
830 | * |
831 | * Expires rtc timers. Reprograms next alarm event if needed. |
832 | * Called via worktask. |
833 | * |
834 | * Serializes access to timerqueue via ops_lock mutex |
835 | */ |
836 | void rtc_timer_do_work(struct work_struct *work) |
837 | { |
838 | struct rtc_timer *timer; |
839 | struct timerqueue_node *next; |
840 | ktime_t now; |
841 | struct rtc_time tm; |
842 | |
843 | struct rtc_device *rtc = |
844 | container_of(work, struct rtc_device, irqwork); |
845 | |
846 | mutex_lock(&rtc->ops_lock); |
847 | again: |
848 | pm_relax(rtc->dev.parent); |
849 | __rtc_read_time(rtc, &tm); |
850 | now = rtc_tm_to_ktime(tm); |
851 | while ((next = timerqueue_getnext(&rtc->timerqueue))) { |
852 | if (next->expires.tv64 > now.tv64) |
853 | break; |
854 | |
855 | /* expire timer */ |
856 | timer = container_of(next, struct rtc_timer, node); |
857 | timerqueue_del(&rtc->timerqueue, &timer->node); |
858 | timer->enabled = 0; |
859 | if (timer->task.func) |
860 | timer->task.func(timer->task.private_data); |
861 | |
862 | /* Re-add/fwd periodic timers */ |
863 | if (ktime_to_ns(timer->period)) { |
864 | timer->node.expires = ktime_add(timer->node.expires, |
865 | timer->period); |
866 | timer->enabled = 1; |
867 | timerqueue_add(&rtc->timerqueue, &timer->node); |
868 | } |
869 | } |
870 | |
871 | /* Set next alarm */ |
872 | if (next) { |
873 | struct rtc_wkalrm alarm; |
874 | int err; |
875 | alarm.time = rtc_ktime_to_tm(next->expires); |
876 | alarm.enabled = 1; |
877 | err = __rtc_set_alarm(rtc, &alarm); |
878 | if (err == -ETIME) |
879 | goto again; |
880 | } else |
881 | rtc_alarm_disable(rtc); |
882 | |
883 | mutex_unlock(&rtc->ops_lock); |
884 | } |
885 | |
886 | |
887 | /* rtc_timer_init - Initializes an rtc_timer |
888 | * @timer: timer to be intiialized |
889 | * @f: function pointer to be called when timer fires |
890 | * @data: private data passed to function pointer |
891 | * |
892 | * Kernel interface to initializing an rtc_timer. |
893 | */ |
894 | void rtc_timer_init(struct rtc_timer *timer, void (*f)(void* p), void* data) |
895 | { |
896 | timerqueue_init(&timer->node); |
897 | timer->enabled = 0; |
898 | timer->task.func = f; |
899 | timer->task.private_data = data; |
900 | } |
901 | |
902 | /* rtc_timer_start - Sets an rtc_timer to fire in the future |
903 | * @ rtc: rtc device to be used |
904 | * @ timer: timer being set |
905 | * @ expires: time at which to expire the timer |
906 | * @ period: period that the timer will recur |
907 | * |
908 | * Kernel interface to set an rtc_timer |
909 | */ |
910 | int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer* timer, |
911 | ktime_t expires, ktime_t period) |
912 | { |
913 | int ret = 0; |
914 | mutex_lock(&rtc->ops_lock); |
915 | if (timer->enabled) |
916 | rtc_timer_remove(rtc, timer); |
917 | |
918 | timer->node.expires = expires; |
919 | timer->period = period; |
920 | |
921 | ret = rtc_timer_enqueue(rtc, timer); |
922 | |
923 | mutex_unlock(&rtc->ops_lock); |
924 | return ret; |
925 | } |
926 | |
927 | /* rtc_timer_cancel - Stops an rtc_timer |
928 | * @ rtc: rtc device to be used |
929 | * @ timer: timer being set |
930 | * |
931 | * Kernel interface to cancel an rtc_timer |
932 | */ |
933 | int rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer* timer) |
934 | { |
935 | int ret = 0; |
936 | mutex_lock(&rtc->ops_lock); |
937 | if (timer->enabled) |
938 | rtc_timer_remove(rtc, timer); |
939 | mutex_unlock(&rtc->ops_lock); |
940 | return ret; |
941 | } |
942 | |
943 | |
944 |
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Tags:
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