alarmtimer.c 18.3 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
/*
 * Alarmtimer interface
 *
 * This interface provides a timer which is similarto hrtimers,
 * but triggers a RTC alarm if the box is suspend.
 *
 * This interface is influenced by the Android RTC Alarm timer
 * interface.
 *
 * Copyright (C) 2010 IBM Corperation
 *
 * Author: John Stultz <john.stultz@linaro.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/time.h>
#include <linux/hrtimer.h>
#include <linux/timerqueue.h>
#include <linux/rtc.h>
#include <linux/alarmtimer.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/posix-timers.h>
#include <linux/workqueue.h>
#include <linux/freezer.h>

29 30 31 32 33 34 35 36
/**
 * struct alarm_base - Alarm timer bases
 * @lock:		Lock for syncrhonized access to the base
 * @timerqueue:		Timerqueue head managing the list of events
 * @timer: 		hrtimer used to schedule events while running
 * @gettime:		Function to read the time correlating to the base
 * @base_clockid:	clockid for the base
 */
37 38 39 40 41 42 43 44
static struct alarm_base {
	spinlock_t		lock;
	struct timerqueue_head	timerqueue;
	struct hrtimer		timer;
	ktime_t			(*gettime)(void);
	clockid_t		base_clockid;
} alarm_bases[ALARM_NUMTYPE];

45 46 47 48
/* freezer delta & lock used to handle clock_nanosleep triggered wakeups */
static ktime_t freezer_delta;
static DEFINE_SPINLOCK(freezer_delta_lock);

49
#ifdef CONFIG_RTC_CLASS
50
/* rtc timer and device for setting alarm wakeups at suspend */
51 52
static struct rtc_timer		rtctimer;
static struct rtc_device	*rtcdev;
53
static DEFINE_SPINLOCK(rtcdev_lock);
54

55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109
/**
 * has_wakealarm - check rtc device has wakealarm ability
 * @dev: current device
 * @name_ptr: name to be returned
 *
 * This helper function checks to see if the rtc device can wake
 * from suspend.
 */
static int has_wakealarm(struct device *dev, void *name_ptr)
{
	struct rtc_device *candidate = to_rtc_device(dev);

	if (!candidate->ops->set_alarm)
		return 0;
	if (!device_may_wakeup(candidate->dev.parent))
		return 0;

	*(const char **)name_ptr = dev_name(dev);
	return 1;
}

/**
 * alarmtimer_get_rtcdev - Return selected rtcdevice
 *
 * This function returns the rtc device to use for wakealarms.
 * If one has not already been chosen, it checks to see if a
 * functional rtc device is available.
 */
static struct rtc_device *alarmtimer_get_rtcdev(void)
{
	struct device *dev;
	char *str;
	unsigned long flags;
	struct rtc_device *ret;

	spin_lock_irqsave(&rtcdev_lock, flags);
	if (!rtcdev) {
		/* Find an rtc device and init the rtc_timer */
		dev = class_find_device(rtc_class, NULL, &str, has_wakealarm);
		/* If we have a device then str is valid. See has_wakealarm() */
		if (dev) {
			rtcdev = rtc_class_open(str);
			/*
			 * Drop the reference we got in class_find_device,
			 * rtc_open takes its own.
			 */
			put_device(dev);
			rtc_timer_init(&rtctimer, NULL, NULL);
		}
	}
	ret = rtcdev;
	spin_unlock_irqrestore(&rtcdev_lock, flags);

	return ret;
}
110 111 112
#else
#define alarmtimer_get_rtcdev() (0)
#define rtcdev (0)
113
#endif
114 115


116
/**
117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135
 * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
 * @base: pointer to the base where the timer is being run
 * @alarm: pointer to alarm being enqueued.
 *
 * Adds alarm to a alarm_base timerqueue and if necessary sets
 * an hrtimer to run.
 *
 * Must hold base->lock when calling.
 */
static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
{
	timerqueue_add(&base->timerqueue, &alarm->node);
	if (&alarm->node == timerqueue_getnext(&base->timerqueue)) {
		hrtimer_try_to_cancel(&base->timer);
		hrtimer_start(&base->timer, alarm->node.expires,
				HRTIMER_MODE_ABS);
	}
}

136
/**
137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159
 * alarmtimer_remove - Removes an alarm timer from an alarm_base timerqueue
 * @base: pointer to the base where the timer is running
 * @alarm: pointer to alarm being removed
 *
 * Removes alarm to a alarm_base timerqueue and if necessary sets
 * a new timer to run.
 *
 * Must hold base->lock when calling.
 */
static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm)
{
	struct timerqueue_node *next = timerqueue_getnext(&base->timerqueue);

	timerqueue_del(&base->timerqueue, &alarm->node);
	if (next == &alarm->node) {
		hrtimer_try_to_cancel(&base->timer);
		next = timerqueue_getnext(&base->timerqueue);
		if (!next)
			return;
		hrtimer_start(&base->timer, next->expires, HRTIMER_MODE_ABS);
	}
}

160

161
/**
162 163
 * alarmtimer_fired - Handles alarm hrtimer being fired.
 * @timer: pointer to hrtimer being run
164
 *
165 166 167 168
 * When a alarm timer fires, this runs through the timerqueue to
 * see which alarms expired, and runs those. If there are more alarm
 * timers queued for the future, we set the hrtimer to fire when
 * when the next future alarm timer expires.
169
 */
170
static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
171
{
172
	struct alarm_base *base = container_of(timer, struct alarm_base, timer);
173 174 175
	struct timerqueue_node *next;
	unsigned long flags;
	ktime_t now;
176
	int ret = HRTIMER_NORESTART;
177
	int restart = ALARMTIMER_NORESTART;
178 179 180 181 182 183 184 185 186 187 188 189 190 191

	spin_lock_irqsave(&base->lock, flags);
	now = base->gettime();
	while ((next = timerqueue_getnext(&base->timerqueue))) {
		struct alarm *alarm;
		ktime_t expired = next->expires;

		if (expired.tv64 >= now.tv64)
			break;

		alarm = container_of(next, struct alarm, node);

		timerqueue_del(&base->timerqueue, &alarm->node);
		alarm->enabled = 0;
192

193 194
		spin_unlock_irqrestore(&base->lock, flags);
		if (alarm->function)
195
			restart = alarm->function(alarm, now);
196
		spin_lock_irqsave(&base->lock, flags);
197 198 199 200 201

		if (restart != ALARMTIMER_NORESTART) {
			timerqueue_add(&base->timerqueue, &alarm->node);
			alarm->enabled = 1;
		}
202 203 204
	}

	if (next) {
205 206
		hrtimer_set_expires(&base->timer, next->expires);
		ret = HRTIMER_RESTART;
207 208 209
	}
	spin_unlock_irqrestore(&base->lock, flags);

210
	return ret;
211 212 213

}

214
#ifdef CONFIG_RTC_CLASS
215
/**
216 217 218 219 220 221 222 223 224 225 226 227 228 229
 * alarmtimer_suspend - Suspend time callback
 * @dev: unused
 * @state: unused
 *
 * When we are going into suspend, we look through the bases
 * to see which is the soonest timer to expire. We then
 * set an rtc timer to fire that far into the future, which
 * will wake us from suspend.
 */
static int alarmtimer_suspend(struct device *dev)
{
	struct rtc_time tm;
	ktime_t min, now;
	unsigned long flags;
230
	struct rtc_device *rtc;
231 232 233 234 235 236 237
	int i;

	spin_lock_irqsave(&freezer_delta_lock, flags);
	min = freezer_delta;
	freezer_delta = ktime_set(0, 0);
	spin_unlock_irqrestore(&freezer_delta_lock, flags);

238
	rtc = rtcdev;
239
	/* If we have no rtcdev, just return */
240
	if (!rtc)
241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264
		return 0;

	/* Find the soonest timer to expire*/
	for (i = 0; i < ALARM_NUMTYPE; i++) {
		struct alarm_base *base = &alarm_bases[i];
		struct timerqueue_node *next;
		ktime_t delta;

		spin_lock_irqsave(&base->lock, flags);
		next = timerqueue_getnext(&base->timerqueue);
		spin_unlock_irqrestore(&base->lock, flags);
		if (!next)
			continue;
		delta = ktime_sub(next->expires, base->gettime());
		if (!min.tv64 || (delta.tv64 < min.tv64))
			min = delta;
	}
	if (min.tv64 == 0)
		return 0;

	/* XXX - Should we enforce a minimum sleep time? */
	WARN_ON(min.tv64 < NSEC_PER_SEC);

	/* Setup an rtc timer to fire that far in the future */
265 266
	rtc_timer_cancel(rtc, &rtctimer);
	rtc_read_time(rtc, &tm);
267 268 269
	now = rtc_tm_to_ktime(tm);
	now = ktime_add(now, min);

270
	rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0));
271 272 273

	return 0;
}
274 275 276 277 278 279
#else
static int alarmtimer_suspend(struct device *dev)
{
	return 0;
}
#endif
280

281 282 283 284 285 286 287 288 289 290 291 292 293 294 295
static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
{
	ktime_t delta;
	unsigned long flags;
	struct alarm_base *base = &alarm_bases[type];

	delta = ktime_sub(absexp, base->gettime());

	spin_lock_irqsave(&freezer_delta_lock, flags);
	if (!freezer_delta.tv64 || (delta.tv64 < freezer_delta.tv64))
		freezer_delta = delta;
	spin_unlock_irqrestore(&freezer_delta_lock, flags);
}


296
/**
297 298 299 300 301 302
 * alarm_init - Initialize an alarm structure
 * @alarm: ptr to alarm to be initialized
 * @type: the type of the alarm
 * @function: callback that is run when the alarm fires
 */
void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
303
		enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
304 305 306 307 308 309 310 311
{
	timerqueue_init(&alarm->node);
	alarm->period = ktime_set(0, 0);
	alarm->function = function;
	alarm->type = type;
	alarm->enabled = 0;
}

312
/**
313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332
 * alarm_start - Sets an alarm to fire
 * @alarm: ptr to alarm to set
 * @start: time to run the alarm
 * @period: period at which the alarm will recur
 */
void alarm_start(struct alarm *alarm, ktime_t start, ktime_t period)
{
	struct alarm_base *base = &alarm_bases[alarm->type];
	unsigned long flags;

	spin_lock_irqsave(&base->lock, flags);
	if (alarm->enabled)
		alarmtimer_remove(base, alarm);
	alarm->node.expires = start;
	alarm->period = period;
	alarmtimer_enqueue(base, alarm);
	alarm->enabled = 1;
	spin_unlock_irqrestore(&base->lock, flags);
}

333
/**
334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349
 * alarm_cancel - Tries to cancel an alarm timer
 * @alarm: ptr to alarm to be canceled
 */
void alarm_cancel(struct alarm *alarm)
{
	struct alarm_base *base = &alarm_bases[alarm->type];
	unsigned long flags;

	spin_lock_irqsave(&base->lock, flags);
	if (alarm->enabled)
		alarmtimer_remove(base, alarm);
	alarm->enabled = 0;
	spin_unlock_irqrestore(&base->lock, flags);
}


350
/**
351 352 353 354 355 356 357 358 359 360 361 362
 * clock2alarm - helper that converts from clockid to alarmtypes
 * @clockid: clockid.
 */
static enum alarmtimer_type clock2alarm(clockid_t clockid)
{
	if (clockid == CLOCK_REALTIME_ALARM)
		return ALARM_REALTIME;
	if (clockid == CLOCK_BOOTTIME_ALARM)
		return ALARM_BOOTTIME;
	return -1;
}

363
/**
364 365 366 367 368
 * alarm_handle_timer - Callback for posix timers
 * @alarm: alarm that fired
 *
 * Posix timer callback for expired alarm timers.
 */
369 370
static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
							ktime_t now)
371 372 373 374 375
{
	struct k_itimer *ptr = container_of(alarm, struct k_itimer,
						it.alarmtimer);
	if (posix_timer_event(ptr, 0) != 0)
		ptr->it_overrun++;
376

377 378 379 380 381
	/* Re-add periodic timers */
	if (alarm->period.tv64) {
		alarm->node.expires = ktime_add(now, alarm->period);
		return ALARMTIMER_RESTART;
	}
382
	return ALARMTIMER_NORESTART;
383 384
}

385
/**
386 387 388 389 390 391 392 393 394 395
 * alarm_clock_getres - posix getres interface
 * @which_clock: clockid
 * @tp: timespec to fill
 *
 * Returns the granularity of underlying alarm base clock
 */
static int alarm_clock_getres(const clockid_t which_clock, struct timespec *tp)
{
	clockid_t baseid = alarm_bases[clock2alarm(which_clock)].base_clockid;

396 397 398
	if (!alarmtimer_get_rtcdev())
		return -ENOTSUPP;

399 400 401 402 403 404 405 406 407 408 409 410 411 412
	return hrtimer_get_res(baseid, tp);
}

/**
 * alarm_clock_get - posix clock_get interface
 * @which_clock: clockid
 * @tp: timespec to fill.
 *
 * Provides the underlying alarm base time.
 */
static int alarm_clock_get(clockid_t which_clock, struct timespec *tp)
{
	struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];

413 414 415
	if (!alarmtimer_get_rtcdev())
		return -ENOTSUPP;

416 417 418 419 420 421 422 423 424 425 426 427 428 429 430
	*tp = ktime_to_timespec(base->gettime());
	return 0;
}

/**
 * alarm_timer_create - posix timer_create interface
 * @new_timer: k_itimer pointer to manage
 *
 * Initializes the k_itimer structure.
 */
static int alarm_timer_create(struct k_itimer *new_timer)
{
	enum  alarmtimer_type type;
	struct alarm_base *base;

431 432 433
	if (!alarmtimer_get_rtcdev())
		return -ENOTSUPP;

434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452
	if (!capable(CAP_WAKE_ALARM))
		return -EPERM;

	type = clock2alarm(new_timer->it_clock);
	base = &alarm_bases[type];
	alarm_init(&new_timer->it.alarmtimer, type, alarm_handle_timer);
	return 0;
}

/**
 * alarm_timer_get - posix timer_get interface
 * @new_timer: k_itimer pointer
 * @cur_setting: itimerspec data to fill
 *
 * Copies the itimerspec data out from the k_itimer
 */
static void alarm_timer_get(struct k_itimer *timr,
				struct itimerspec *cur_setting)
{
453 454
	memset(cur_setting, 0, sizeof(struct itimerspec));

455 456 457 458 459 460 461 462 463 464 465 466 467 468 469
	cur_setting->it_interval =
			ktime_to_timespec(timr->it.alarmtimer.period);
	cur_setting->it_value =
			ktime_to_timespec(timr->it.alarmtimer.node.expires);
	return;
}

/**
 * alarm_timer_del - posix timer_del interface
 * @timr: k_itimer pointer to be deleted
 *
 * Cancels any programmed alarms for the given timer.
 */
static int alarm_timer_del(struct k_itimer *timr)
{
470 471 472
	if (!rtcdev)
		return -ENOTSUPP;

473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489
	alarm_cancel(&timr->it.alarmtimer);
	return 0;
}

/**
 * alarm_timer_set - posix timer_set interface
 * @timr: k_itimer pointer to be deleted
 * @flags: timer flags
 * @new_setting: itimerspec to be used
 * @old_setting: itimerspec being replaced
 *
 * Sets the timer to new_setting, and starts the timer.
 */
static int alarm_timer_set(struct k_itimer *timr, int flags,
				struct itimerspec *new_setting,
				struct itimerspec *old_setting)
{
490 491 492
	if (!rtcdev)
		return -ENOTSUPP;

493 494 495 496 497 498 499 500 501
	/*
	 * XXX HACK! Currently we can DOS a system if the interval
	 * period on alarmtimers is too small. Cap the interval here
	 * to 100us and solve this properly in a future patch! -jstultz
	 */
	if ((new_setting->it_interval.tv_sec == 0) &&
			(new_setting->it_interval.tv_nsec < 100000))
		new_setting->it_interval.tv_nsec = 100000;

502 503
	if (old_setting)
		alarm_timer_get(timr, old_setting);
504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520

	/* If the timer was already set, cancel it */
	alarm_cancel(&timr->it.alarmtimer);

	/* start the timer */
	alarm_start(&timr->it.alarmtimer,
			timespec_to_ktime(new_setting->it_value),
			timespec_to_ktime(new_setting->it_interval));
	return 0;
}

/**
 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
 * @alarm: ptr to alarm that fired
 *
 * Wakes up the task that set the alarmtimer
 */
521 522
static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
								ktime_t now)
523 524 525 526 527 528
{
	struct task_struct *task = (struct task_struct *)alarm->data;

	alarm->data = NULL;
	if (task)
		wake_up_process(task);
529
	return ALARMTIMER_NORESTART;
530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592
}

/**
 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
 * @alarm: ptr to alarmtimer
 * @absexp: absolute expiration time
 *
 * Sets the alarm timer and sleeps until it is fired or interrupted.
 */
static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp)
{
	alarm->data = (void *)current;
	do {
		set_current_state(TASK_INTERRUPTIBLE);
		alarm_start(alarm, absexp, ktime_set(0, 0));
		if (likely(alarm->data))
			schedule();

		alarm_cancel(alarm);
	} while (alarm->data && !signal_pending(current));

	__set_current_state(TASK_RUNNING);

	return (alarm->data == NULL);
}


/**
 * update_rmtp - Update remaining timespec value
 * @exp: expiration time
 * @type: timer type
 * @rmtp: user pointer to remaining timepsec value
 *
 * Helper function that fills in rmtp value with time between
 * now and the exp value
 */
static int update_rmtp(ktime_t exp, enum  alarmtimer_type type,
			struct timespec __user *rmtp)
{
	struct timespec rmt;
	ktime_t rem;

	rem = ktime_sub(exp, alarm_bases[type].gettime());

	if (rem.tv64 <= 0)
		return 0;
	rmt = ktime_to_timespec(rem);

	if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
		return -EFAULT;

	return 1;

}

/**
 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
 * @restart: ptr to restart block
 *
 * Handles restarted clock_nanosleep calls
 */
static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
{
593
	enum  alarmtimer_type type = restart->nanosleep.clockid;
594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639
	ktime_t exp;
	struct timespec __user  *rmtp;
	struct alarm alarm;
	int ret = 0;

	exp.tv64 = restart->nanosleep.expires;
	alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);

	if (alarmtimer_do_nsleep(&alarm, exp))
		goto out;

	if (freezing(current))
		alarmtimer_freezerset(exp, type);

	rmtp = restart->nanosleep.rmtp;
	if (rmtp) {
		ret = update_rmtp(exp, type, rmtp);
		if (ret <= 0)
			goto out;
	}


	/* The other values in restart are already filled in */
	ret = -ERESTART_RESTARTBLOCK;
out:
	return ret;
}

/**
 * alarm_timer_nsleep - alarmtimer nanosleep
 * @which_clock: clockid
 * @flags: determins abstime or relative
 * @tsreq: requested sleep time (abs or rel)
 * @rmtp: remaining sleep time saved
 *
 * Handles clock_nanosleep calls against _ALARM clockids
 */
static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
		     struct timespec *tsreq, struct timespec __user *rmtp)
{
	enum  alarmtimer_type type = clock2alarm(which_clock);
	struct alarm alarm;
	ktime_t exp;
	int ret = 0;
	struct restart_block *restart;

640 641 642
	if (!alarmtimer_get_rtcdev())
		return -ENOTSUPP;

643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674
	if (!capable(CAP_WAKE_ALARM))
		return -EPERM;

	alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);

	exp = timespec_to_ktime(*tsreq);
	/* Convert (if necessary) to absolute time */
	if (flags != TIMER_ABSTIME) {
		ktime_t now = alarm_bases[type].gettime();
		exp = ktime_add(now, exp);
	}

	if (alarmtimer_do_nsleep(&alarm, exp))
		goto out;

	if (freezing(current))
		alarmtimer_freezerset(exp, type);

	/* abs timers don't set remaining time or restart */
	if (flags == TIMER_ABSTIME) {
		ret = -ERESTARTNOHAND;
		goto out;
	}

	if (rmtp) {
		ret = update_rmtp(exp, type, rmtp);
		if (ret <= 0)
			goto out;
	}

	restart = &current_thread_info()->restart_block;
	restart->fn = alarm_timer_nsleep_restart;
675
	restart->nanosleep.clockid = type;
676 677 678 679 680 681 682
	restart->nanosleep.expires = exp.tv64;
	restart->nanosleep.rmtp = rmtp;
	ret = -ERESTART_RESTARTBLOCK;

out:
	return ret;
}
683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706


/* Suspend hook structures */
static const struct dev_pm_ops alarmtimer_pm_ops = {
	.suspend = alarmtimer_suspend,
};

static struct platform_driver alarmtimer_driver = {
	.driver = {
		.name = "alarmtimer",
		.pm = &alarmtimer_pm_ops,
	}
};

/**
 * alarmtimer_init - Initialize alarm timer code
 *
 * This function initializes the alarm bases and registers
 * the posix clock ids.
 */
static int __init alarmtimer_init(void)
{
	int error = 0;
	int i;
707 708 709 710 711 712 713 714 715 716 717 718
	struct k_clock alarm_clock = {
		.clock_getres	= alarm_clock_getres,
		.clock_get	= alarm_clock_get,
		.timer_create	= alarm_timer_create,
		.timer_set	= alarm_timer_set,
		.timer_del	= alarm_timer_del,
		.timer_get	= alarm_timer_get,
		.nsleep		= alarm_timer_nsleep,
	};

	posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock);
	posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock);
719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739

	/* Initialize alarm bases */
	alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
	alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
	alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
	alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
	for (i = 0; i < ALARM_NUMTYPE; i++) {
		timerqueue_init_head(&alarm_bases[i].timerqueue);
		spin_lock_init(&alarm_bases[i].lock);
		hrtimer_init(&alarm_bases[i].timer,
				alarm_bases[i].base_clockid,
				HRTIMER_MODE_ABS);
		alarm_bases[i].timer.function = alarmtimer_fired;
	}
	error = platform_driver_register(&alarmtimer_driver);
	platform_device_register_simple("alarmtimer", -1, NULL, 0);

	return error;
}
device_initcall(alarmtimer_init);