projects/linux·blob v2.6.38 · refs

684 lines · 16.2 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/log2.h>
17#include <linux/workqueue.h>
18
19static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer);
20static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer);
21
22static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
23{
24 int err;
25 if (!rtc->ops)
26 err = -ENODEV;
27 else if (!rtc->ops->read_time)
28 err = -EINVAL;
29 else {
30 memset(tm, 0, sizeof(struct rtc_time));
31 err = rtc->ops->read_time(rtc->dev.parent, tm);
32 }
33 return err;
34}
35
36int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
37{
38 int err;
39
40 err = mutex_lock_interruptible(&rtc->ops_lock);
41 if (err)
42 return err;
43
44 err = __rtc_read_time(rtc, tm);
45 mutex_unlock(&rtc->ops_lock);
46 return err;
47}
48EXPORT_SYMBOL_GPL(rtc_read_time);
49
50int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
51{
52 int err;
53
54 err = rtc_valid_tm(tm);
55 if (err != 0)
56 return err;
57
58 err = mutex_lock_interruptible(&rtc->ops_lock);
59 if (err)
60 return err;
61
62 if (!rtc->ops)
63 err = -ENODEV;
64 else if (rtc->ops->set_time)
65 err = rtc->ops->set_time(rtc->dev.parent, tm);
66 else if (rtc->ops->set_mmss) {
67 unsigned long secs;
68 err = rtc_tm_to_time(tm, &secs);
69 if (err == 0)
70 err = rtc->ops->set_mmss(rtc->dev.parent, secs);
71 } else
72 err = -EINVAL;
73
74 mutex_unlock(&rtc->ops_lock);
75 return err;
76}
77EXPORT_SYMBOL_GPL(rtc_set_time);
78
79int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs)
80{
81 int err;
82
83 err = mutex_lock_interruptible(&rtc->ops_lock);
84 if (err)
85 return err;
86
87 if (!rtc->ops)
88 err = -ENODEV;
89 else if (rtc->ops->set_mmss)
90 err = rtc->ops->set_mmss(rtc->dev.parent, secs);
91 else if (rtc->ops->read_time && rtc->ops->set_time) {
92 struct rtc_time new, old;
93
94 err = rtc->ops->read_time(rtc->dev.parent, &old);
95 if (err == 0) {
96 rtc_time_to_tm(secs, &new);
97
98 /*
99 * avoid writing when we're going to change the day of
100 * the month. We will retry in the next minute. This
101 * basically means that if the RTC must not drift
102 * by more than 1 minute in 11 minutes.
103 */
104 if (!((old.tm_hour == 23 && old.tm_min == 59) ||
105 (new.tm_hour == 23 && new.tm_min == 59)))
106 err = rtc->ops->set_time(rtc->dev.parent,
107 &new);
108 }
109 }
110 else
111 err = -EINVAL;
112
113 mutex_unlock(&rtc->ops_lock);
114
115 return err;
116}
117EXPORT_SYMBOL_GPL(rtc_set_mmss);
118
119int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
120{
121 int err;
122
123 err = mutex_lock_interruptible(&rtc->ops_lock);
124 if (err)
125 return err;
126 if (rtc->ops == NULL)
127 err = -ENODEV;
128 else if (!rtc->ops->read_alarm)
129 err = -EINVAL;
130 else {
131 memset(alarm, 0, sizeof(struct rtc_wkalrm));
132 alarm->enabled = rtc->aie_timer.enabled;
133 alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
134 }
135 mutex_unlock(&rtc->ops_lock);
136
137 return err;
138}
139EXPORT_SYMBOL_GPL(rtc_read_alarm);
140
141int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
142{
143 struct rtc_time tm;
144 long now, scheduled;
145 int err;
146
147 err = rtc_valid_tm(&alarm->time);
148 if (err)
149 return err;
150 rtc_tm_to_time(&alarm->time, &scheduled);
151
152 /* Make sure we're not setting alarms in the past */
153 err = __rtc_read_time(rtc, &tm);
154 rtc_tm_to_time(&tm, &now);
155 if (scheduled <= now)
156 return -ETIME;
157 /*
158 * XXX - We just checked to make sure the alarm time is not
159 * in the past, but there is still a race window where if
160 * the is alarm set for the next second and the second ticks
161 * over right here, before we set the alarm.
162 */
163
164 if (!rtc->ops)
165 err = -ENODEV;
166 else if (!rtc->ops->set_alarm)
167 err = -EINVAL;
168 else
169 err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
170
171 return err;
172}
173
174int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
175{
176 int err;
177
178 err = rtc_valid_tm(&alarm->time);
179 if (err != 0)
180 return err;
181
182 err = mutex_lock_interruptible(&rtc->ops_lock);
183 if (err)
184 return err;
185 if (rtc->aie_timer.enabled) {
186 rtc_timer_remove(rtc, &rtc->aie_timer);
187 }
188 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
189 rtc->aie_timer.period = ktime_set(0, 0);
190 if (alarm->enabled) {
191 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
192 }
193 mutex_unlock(&rtc->ops_lock);
194 return err;
195}
196EXPORT_SYMBOL_GPL(rtc_set_alarm);
197
198int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
199{
200 int err = mutex_lock_interruptible(&rtc->ops_lock);
201 if (err)
202 return err;
203
204 if (rtc->aie_timer.enabled != enabled) {
205 if (enabled)
206 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
207 else
208 rtc_timer_remove(rtc, &rtc->aie_timer);
209 }
210
211 if (err)
212 /* nothing */;
213 else if (!rtc->ops)
214 err = -ENODEV;
215 else if (!rtc->ops->alarm_irq_enable)
216 err = -EINVAL;
217 else
218 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
219
220 mutex_unlock(&rtc->ops_lock);
221 return err;
222}
223EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
224
225int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
226{
227 int err = mutex_lock_interruptible(&rtc->ops_lock);
228 if (err)
229 return err;
230
231#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
232 if (enabled == 0 && rtc->uie_irq_active) {
233 mutex_unlock(&rtc->ops_lock);
234 return rtc_dev_update_irq_enable_emul(rtc, 0);
235 }
236#endif
237 /* make sure we're changing state */
238 if (rtc->uie_rtctimer.enabled == enabled)
239 goto out;
240
241 if (enabled) {
242 struct rtc_time tm;
243 ktime_t now, onesec;
244
245 __rtc_read_time(rtc, &tm);
246 onesec = ktime_set(1, 0);
247 now = rtc_tm_to_ktime(tm);
248 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
249 rtc->uie_rtctimer.period = ktime_set(1, 0);
250 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
251 } else
252 rtc_timer_remove(rtc, &rtc->uie_rtctimer);
253
254out:
255 mutex_unlock(&rtc->ops_lock);
256#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
257 /*
258 * Enable emulation if the driver did not provide
259 * the update_irq_enable function pointer or if returned
260 * -EINVAL to signal that it has been configured without
261 * interrupts or that are not available at the moment.
262 */
263 if (err == -EINVAL)
264 err = rtc_dev_update_irq_enable_emul(rtc, enabled);
265#endif
266 return err;
267
268}
269EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
270
271
272/**
273 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
274 * @rtc: pointer to the rtc device
275 *
276 * This function is called when an AIE, UIE or PIE mode interrupt
277 * has occured (or been emulated).
278 *
279 * Triggers the registered irq_task function callback.
280 */
281void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
282{
283 unsigned long flags;
284
285 /* mark one irq of the appropriate mode */
286 spin_lock_irqsave(&rtc->irq_lock, flags);
287 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF|mode);
288 spin_unlock_irqrestore(&rtc->irq_lock, flags);
289
290 /* call the task func */
291 spin_lock_irqsave(&rtc->irq_task_lock, flags);
292 if (rtc->irq_task)
293 rtc->irq_task->func(rtc->irq_task->private_data);
294 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
295
296 wake_up_interruptible(&rtc->irq_queue);
297 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
298}
299
300
301/**
302 * rtc_aie_update_irq - AIE mode rtctimer hook
303 * @private: pointer to the rtc_device
304 *
305 * This functions is called when the aie_timer expires.
306 */
307void rtc_aie_update_irq(void *private)
308{
309 struct rtc_device *rtc = (struct rtc_device *)private;
310 rtc_handle_legacy_irq(rtc, 1, RTC_AF);
311}
312
313
314/**
315 * rtc_uie_update_irq - UIE mode rtctimer hook
316 * @private: pointer to the rtc_device
317 *
318 * This functions is called when the uie_timer expires.
319 */
320void rtc_uie_update_irq(void *private)
321{
322 struct rtc_device *rtc = (struct rtc_device *)private;
323 rtc_handle_legacy_irq(rtc, 1, RTC_UF);
324}
325
326
327/**
328 * rtc_pie_update_irq - PIE mode hrtimer hook
329 * @timer: pointer to the pie mode hrtimer
330 *
331 * This function is used to emulate PIE mode interrupts
332 * using an hrtimer. This function is called when the periodic
333 * hrtimer expires.
334 */
335enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
336{
337 struct rtc_device *rtc;
338 ktime_t period;
339 int count;
340 rtc = container_of(timer, struct rtc_device, pie_timer);
341
342 period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
343 count = hrtimer_forward_now(timer, period);
344
345 rtc_handle_legacy_irq(rtc, count, RTC_PF);
346
347 return HRTIMER_RESTART;
348}
349
350/**
351 * rtc_update_irq - Triggered when a RTC interrupt occurs.
352 * @rtc: the rtc device
353 * @num: how many irqs are being reported (usually one)
354 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
355 * Context: any
356 */
357void rtc_update_irq(struct rtc_device *rtc,
358 unsigned long num, unsigned long events)
359{
360 schedule_work(&rtc->irqwork);
361}
362EXPORT_SYMBOL_GPL(rtc_update_irq);
363
364static int __rtc_match(struct device *dev, void *data)
365{
366 char *name = (char *)data;
367
368 if (strcmp(dev_name(dev), name) == 0)
369 return 1;
370 return 0;
371}
372
373struct rtc_device *rtc_class_open(char *name)
374{
375 struct device *dev;
376 struct rtc_device *rtc = NULL;
377
378 dev = class_find_device(rtc_class, NULL, name, __rtc_match);
379 if (dev)
380 rtc = to_rtc_device(dev);
381
382 if (rtc) {
383 if (!try_module_get(rtc->owner)) {
384 put_device(dev);
385 rtc = NULL;
386 }
387 }
388
389 return rtc;
390}
391EXPORT_SYMBOL_GPL(rtc_class_open);
392
393void rtc_class_close(struct rtc_device *rtc)
394{
395 module_put(rtc->owner);
396 put_device(&rtc->dev);
397}
398EXPORT_SYMBOL_GPL(rtc_class_close);
399
400int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
401{
402 int retval = -EBUSY;
403
404 if (task == NULL || task->func == NULL)
405 return -EINVAL;
406
407 /* Cannot register while the char dev is in use */
408 if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
409 return -EBUSY;
410
411 spin_lock_irq(&rtc->irq_task_lock);
412 if (rtc->irq_task == NULL) {
413 rtc->irq_task = task;
414 retval = 0;
415 }
416 spin_unlock_irq(&rtc->irq_task_lock);
417
418 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
419
420 return retval;
421}
422EXPORT_SYMBOL_GPL(rtc_irq_register);
423
424void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task)
425{
426 spin_lock_irq(&rtc->irq_task_lock);
427 if (rtc->irq_task == task)
428 rtc->irq_task = NULL;
429 spin_unlock_irq(&rtc->irq_task_lock);
430}
431EXPORT_SYMBOL_GPL(rtc_irq_unregister);
432
433/**
434 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
435 * @rtc: the rtc device
436 * @task: currently registered with rtc_irq_register()
437 * @enabled: true to enable periodic IRQs
438 * Context: any
439 *
440 * Note that rtc_irq_set_freq() should previously have been used to
441 * specify the desired frequency of periodic IRQ task->func() callbacks.
442 */
443int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled)
444{
445 int err = 0;
446 unsigned long flags;
447
448 spin_lock_irqsave(&rtc->irq_task_lock, flags);
449 if (rtc->irq_task != NULL && task == NULL)
450 err = -EBUSY;
451 if (rtc->irq_task != task)
452 err = -EACCES;
453
454 if (enabled) {
455 ktime_t period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
456 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
457 } else {
458 hrtimer_cancel(&rtc->pie_timer);
459 }
460 rtc->pie_enabled = enabled;
461 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
462
463 return err;
464}
465EXPORT_SYMBOL_GPL(rtc_irq_set_state);
466
467/**
468 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
469 * @rtc: the rtc device
470 * @task: currently registered with rtc_irq_register()
471 * @freq: positive frequency with which task->func() will be called
472 * Context: any
473 *
474 * Note that rtc_irq_set_state() is used to enable or disable the
475 * periodic IRQs.
476 */
477int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
478{
479 int err = 0;
480 unsigned long flags;
481
482 if (freq <= 0)
483 return -EINVAL;
484
485 spin_lock_irqsave(&rtc->irq_task_lock, flags);
486 if (rtc->irq_task != NULL && task == NULL)
487 err = -EBUSY;
488 if (rtc->irq_task != task)
489 err = -EACCES;
490 if (err == 0) {
491 rtc->irq_freq = freq;
492 if (rtc->pie_enabled) {
493 ktime_t period;
494 hrtimer_cancel(&rtc->pie_timer);
495 period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
496 hrtimer_start(&rtc->pie_timer, period,
497 HRTIMER_MODE_REL);
498 }
499 }
500 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
501 return err;
502}
503EXPORT_SYMBOL_GPL(rtc_irq_set_freq);
504
505/**
506 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
507 * @rtc rtc device
508 * @timer timer being added.
509 *
510 * Enqueues a timer onto the rtc devices timerqueue and sets
511 * the next alarm event appropriately.
512 *
513 * Sets the enabled bit on the added timer.
514 *
515 * Must hold ops_lock for proper serialization of timerqueue
516 */
517static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
518{
519 timer->enabled = 1;
520 timerqueue_add(&rtc->timerqueue, &timer->node);
521 if (&timer->node == timerqueue_getnext(&rtc->timerqueue)) {
522 struct rtc_wkalrm alarm;
523 int err;
524 alarm.time = rtc_ktime_to_tm(timer->node.expires);
525 alarm.enabled = 1;
526 err = __rtc_set_alarm(rtc, &alarm);
527 if (err == -ETIME)
528 schedule_work(&rtc->irqwork);
529 else if (err) {
530 timerqueue_del(&rtc->timerqueue, &timer->node);
531 timer->enabled = 0;
532 return err;
533 }
534 }
535 return 0;
536}
537
538/**
539 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
540 * @rtc rtc device
541 * @timer timer being removed.
542 *
543 * Removes a timer onto the rtc devices timerqueue and sets
544 * the next alarm event appropriately.
545 *
546 * Clears the enabled bit on the removed timer.
547 *
548 * Must hold ops_lock for proper serialization of timerqueue
549 */
550static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
551{
552 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
553 timerqueue_del(&rtc->timerqueue, &timer->node);
554 timer->enabled = 0;
555 if (next == &timer->node) {
556 struct rtc_wkalrm alarm;
557 int err;
558 next = timerqueue_getnext(&rtc->timerqueue);
559 if (!next)
560 return;
561 alarm.time = rtc_ktime_to_tm(next->expires);
562 alarm.enabled = 1;
563 err = __rtc_set_alarm(rtc, &alarm);
564 if (err == -ETIME)
565 schedule_work(&rtc->irqwork);
566 }
567}
568
569/**
570 * rtc_timer_do_work - Expires rtc timers
571 * @rtc rtc device
572 * @timer timer being removed.
573 *
574 * Expires rtc timers. Reprograms next alarm event if needed.
575 * Called via worktask.
576 *
577 * Serializes access to timerqueue via ops_lock mutex
578 */
579void rtc_timer_do_work(struct work_struct *work)
580{
581 struct rtc_timer *timer;
582 struct timerqueue_node *next;
583 ktime_t now;
584 struct rtc_time tm;
585
586 struct rtc_device *rtc =
587 container_of(work, struct rtc_device, irqwork);
588
589 mutex_lock(&rtc->ops_lock);
590again:
591 __rtc_read_time(rtc, &tm);
592 now = rtc_tm_to_ktime(tm);
593 while ((next = timerqueue_getnext(&rtc->timerqueue))) {
594 if (next->expires.tv64 > now.tv64)
595 break;
596
597 /* expire timer */
598 timer = container_of(next, struct rtc_timer, node);
599 timerqueue_del(&rtc->timerqueue, &timer->node);
600 timer->enabled = 0;
601 if (timer->task.func)
602 timer->task.func(timer->task.private_data);
603
604 /* Re-add/fwd periodic timers */
605 if (ktime_to_ns(timer->period)) {
606 timer->node.expires = ktime_add(timer->node.expires,
607 timer->period);
608 timer->enabled = 1;
609 timerqueue_add(&rtc->timerqueue, &timer->node);
610 }
611 }
612
613 /* Set next alarm */
614 if (next) {
615 struct rtc_wkalrm alarm;
616 int err;
617 alarm.time = rtc_ktime_to_tm(next->expires);
618 alarm.enabled = 1;
619 err = __rtc_set_alarm(rtc, &alarm);
620 if (err == -ETIME)
621 goto again;
622 }
623
624 mutex_unlock(&rtc->ops_lock);
625}
626
627
628/* rtc_timer_init - Initializes an rtc_timer
629 * @timer: timer to be intiialized
630 * @f: function pointer to be called when timer fires
631 * @data: private data passed to function pointer
632 *
633 * Kernel interface to initializing an rtc_timer.
634 */
635void rtc_timer_init(struct rtc_timer *timer, void (*f)(void* p), void* data)
636{
637 timerqueue_init(&timer->node);
638 timer->enabled = 0;
639 timer->task.func = f;
640 timer->task.private_data = data;
641}
642
643/* rtc_timer_start - Sets an rtc_timer to fire in the future
644 * @ rtc: rtc device to be used
645 * @ timer: timer being set
646 * @ expires: time at which to expire the timer
647 * @ period: period that the timer will recur
648 *
649 * Kernel interface to set an rtc_timer
650 */
651int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer* timer,
652 ktime_t expires, ktime_t period)
653{
654 int ret = 0;
655 mutex_lock(&rtc->ops_lock);
656 if (timer->enabled)
657 rtc_timer_remove(rtc, timer);
658
659 timer->node.expires = expires;
660 timer->period = period;
661
662 ret = rtc_timer_enqueue(rtc, timer);
663
664 mutex_unlock(&rtc->ops_lock);
665 return ret;
666}
667
668/* rtc_timer_cancel - Stops an rtc_timer
669 * @ rtc: rtc device to be used
670 * @ timer: timer being set
671 *
672 * Kernel interface to cancel an rtc_timer
673 */
674int rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer* timer)
675{
676 int ret = 0;
677 mutex_lock(&rtc->ops_lock);
678 if (timer->enabled)
679 rtc_timer_remove(rtc, timer);
680 mutex_unlock(&rtc->ops_lock);
681 return ret;
682}
683
684