linux/kernel/time/alarmtimer.c
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   1/*
   2 * Alarmtimer interface
   3 *
   4 * This interface provides a timer which is similarto hrtimers,
   5 * but triggers a RTC alarm if the box is suspend.
   6 *
   7 * This interface is influenced by the Android RTC Alarm timer
   8 * interface.
   9 *
  10 * Copyright (C) 2010 IBM Corperation
  11 *
  12 * Author: John Stultz <john.stultz@linaro.org>
  13 *
  14 * This program is free software; you can redistribute it and/or modify
  15 * it under the terms of the GNU General Public License version 2 as
  16 * published by the Free Software Foundation.
  17 */
  18#include <linux/time.h>
  19#include <linux/hrtimer.h>
  20#include <linux/timerqueue.h>
  21#include <linux/rtc.h>
  22#include <linux/alarmtimer.h>
  23#include <linux/mutex.h>
  24#include <linux/platform_device.h>
  25#include <linux/posix-timers.h>
  26#include <linux/workqueue.h>
  27#include <linux/freezer.h>
  28
  29/**
  30 * struct alarm_base - Alarm timer bases
  31 * @lock:               Lock for syncrhonized access to the base
  32 * @timerqueue:         Timerqueue head managing the list of events
  33 * @timer:              hrtimer used to schedule events while running
  34 * @gettime:            Function to read the time correlating to the base
  35 * @base_clockid:       clockid for the base
  36 */
  37static struct alarm_base {
  38        spinlock_t              lock;
  39        struct timerqueue_head  timerqueue;
  40        ktime_t                 (*gettime)(void);
  41        clockid_t               base_clockid;
  42} alarm_bases[ALARM_NUMTYPE];
  43
  44/* freezer delta & lock used to handle clock_nanosleep triggered wakeups */
  45static ktime_t freezer_delta;
  46static DEFINE_SPINLOCK(freezer_delta_lock);
  47
  48static struct wakeup_source *ws;
  49
  50#ifdef CONFIG_RTC_CLASS
  51/* rtc timer and device for setting alarm wakeups at suspend */
  52static struct rtc_timer         rtctimer;
  53static struct rtc_device        *rtcdev;
  54static DEFINE_SPINLOCK(rtcdev_lock);
  55
  56/**
  57 * alarmtimer_get_rtcdev - Return selected rtcdevice
  58 *
  59 * This function returns the rtc device to use for wakealarms.
  60 * If one has not already been chosen, it checks to see if a
  61 * functional rtc device is available.
  62 */
  63struct rtc_device *alarmtimer_get_rtcdev(void)
  64{
  65        unsigned long flags;
  66        struct rtc_device *ret;
  67
  68        spin_lock_irqsave(&rtcdev_lock, flags);
  69        ret = rtcdev;
  70        spin_unlock_irqrestore(&rtcdev_lock, flags);
  71
  72        return ret;
  73}
  74
  75
  76static int alarmtimer_rtc_add_device(struct device *dev,
  77                                struct class_interface *class_intf)
  78{
  79        unsigned long flags;
  80        struct rtc_device *rtc = to_rtc_device(dev);
  81
  82        if (rtcdev)
  83                return -EBUSY;
  84
  85        if (!rtc->ops->set_alarm)
  86                return -1;
  87        if (!device_may_wakeup(rtc->dev.parent))
  88                return -1;
  89
  90        spin_lock_irqsave(&rtcdev_lock, flags);
  91        if (!rtcdev) {
  92                rtcdev = rtc;
  93                /* hold a reference so it doesn't go away */
  94                get_device(dev);
  95        }
  96        spin_unlock_irqrestore(&rtcdev_lock, flags);
  97        return 0;
  98}
  99
 100static inline void alarmtimer_rtc_timer_init(void)
 101{
 102        rtc_timer_init(&rtctimer, NULL, NULL);
 103}
 104
 105static struct class_interface alarmtimer_rtc_interface = {
 106        .add_dev = &alarmtimer_rtc_add_device,
 107};
 108
 109static int alarmtimer_rtc_interface_setup(void)
 110{
 111        alarmtimer_rtc_interface.class = rtc_class;
 112        return class_interface_register(&alarmtimer_rtc_interface);
 113}
 114static void alarmtimer_rtc_interface_remove(void)
 115{
 116        class_interface_unregister(&alarmtimer_rtc_interface);
 117}
 118#else
 119struct rtc_device *alarmtimer_get_rtcdev(void)
 120{
 121        return NULL;
 122}
 123#define rtcdev (NULL)
 124static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
 125static inline void alarmtimer_rtc_interface_remove(void) { }
 126static inline void alarmtimer_rtc_timer_init(void) { }
 127#endif
 128
 129/**
 130 * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
 131 * @base: pointer to the base where the timer is being run
 132 * @alarm: pointer to alarm being enqueued.
 133 *
 134 * Adds alarm to a alarm_base timerqueue
 135 *
 136 * Must hold base->lock when calling.
 137 */
 138static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
 139{
 140        if (alarm->state & ALARMTIMER_STATE_ENQUEUED)
 141                timerqueue_del(&base->timerqueue, &alarm->node);
 142
 143        timerqueue_add(&base->timerqueue, &alarm->node);
 144        alarm->state |= ALARMTIMER_STATE_ENQUEUED;
 145}
 146
 147/**
 148 * alarmtimer_dequeue - Removes an alarm timer from an alarm_base timerqueue
 149 * @base: pointer to the base where the timer is running
 150 * @alarm: pointer to alarm being removed
 151 *
 152 * Removes alarm to a alarm_base timerqueue
 153 *
 154 * Must hold base->lock when calling.
 155 */
 156static void alarmtimer_dequeue(struct alarm_base *base, struct alarm *alarm)
 157{
 158        if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
 159                return;
 160
 161        timerqueue_del(&base->timerqueue, &alarm->node);
 162        alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
 163}
 164
 165
 166/**
 167 * alarmtimer_fired - Handles alarm hrtimer being fired.
 168 * @timer: pointer to hrtimer being run
 169 *
 170 * When a alarm timer fires, this runs through the timerqueue to
 171 * see which alarms expired, and runs those. If there are more alarm
 172 * timers queued for the future, we set the hrtimer to fire when
 173 * when the next future alarm timer expires.
 174 */
 175static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
 176{
 177        struct alarm *alarm = container_of(timer, struct alarm, timer);
 178        struct alarm_base *base = &alarm_bases[alarm->type];
 179        unsigned long flags;
 180        int ret = HRTIMER_NORESTART;
 181        int restart = ALARMTIMER_NORESTART;
 182
 183        spin_lock_irqsave(&base->lock, flags);
 184        alarmtimer_dequeue(base, alarm);
 185        spin_unlock_irqrestore(&base->lock, flags);
 186
 187        if (alarm->function)
 188                restart = alarm->function(alarm, base->gettime());
 189
 190        spin_lock_irqsave(&base->lock, flags);
 191        if (restart != ALARMTIMER_NORESTART) {
 192                hrtimer_set_expires(&alarm->timer, alarm->node.expires);
 193                alarmtimer_enqueue(base, alarm);
 194                ret = HRTIMER_RESTART;
 195        }
 196        spin_unlock_irqrestore(&base->lock, flags);
 197
 198        return ret;
 199
 200}
 201
 202#ifdef CONFIG_RTC_CLASS
 203/**
 204 * alarmtimer_suspend - Suspend time callback
 205 * @dev: unused
 206 * @state: unused
 207 *
 208 * When we are going into suspend, we look through the bases
 209 * to see which is the soonest timer to expire. We then
 210 * set an rtc timer to fire that far into the future, which
 211 * will wake us from suspend.
 212 */
 213static int alarmtimer_suspend(struct device *dev)
 214{
 215        struct rtc_time tm;
 216        ktime_t min, now;
 217        unsigned long flags;
 218        struct rtc_device *rtc;
 219        int i;
 220        int ret;
 221
 222        spin_lock_irqsave(&freezer_delta_lock, flags);
 223        min = freezer_delta;
 224        freezer_delta = ktime_set(0, 0);
 225        spin_unlock_irqrestore(&freezer_delta_lock, flags);
 226
 227        rtc = alarmtimer_get_rtcdev();
 228        /* If we have no rtcdev, just return */
 229        if (!rtc)
 230                return 0;
 231
 232        /* Find the soonest timer to expire*/
 233        for (i = 0; i < ALARM_NUMTYPE; i++) {
 234                struct alarm_base *base = &alarm_bases[i];
 235                struct timerqueue_node *next;
 236                ktime_t delta;
 237
 238                spin_lock_irqsave(&base->lock, flags);
 239                next = timerqueue_getnext(&base->timerqueue);
 240                spin_unlock_irqrestore(&base->lock, flags);
 241                if (!next)
 242                        continue;
 243                delta = ktime_sub(next->expires, base->gettime());
 244                if (!min.tv64 || (delta.tv64 < min.tv64))
 245                        min = delta;
 246        }
 247        if (min.tv64 == 0)
 248                return 0;
 249
 250        if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) {
 251                __pm_wakeup_event(ws, 2 * MSEC_PER_SEC);
 252                return -EBUSY;
 253        }
 254
 255        /* Setup an rtc timer to fire that far in the future */
 256        rtc_timer_cancel(rtc, &rtctimer);
 257        rtc_read_time(rtc, &tm);
 258        now = rtc_tm_to_ktime(tm);
 259        now = ktime_add(now, min);
 260
 261        /* Set alarm, if in the past reject suspend briefly to handle */
 262        ret = rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0));
 263        if (ret < 0)
 264                __pm_wakeup_event(ws, MSEC_PER_SEC);
 265        return ret;
 266}
 267#else
 268static int alarmtimer_suspend(struct device *dev)
 269{
 270        return 0;
 271}
 272#endif
 273
 274static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
 275{
 276        ktime_t delta;
 277        unsigned long flags;
 278        struct alarm_base *base = &alarm_bases[type];
 279
 280        delta = ktime_sub(absexp, base->gettime());
 281
 282        spin_lock_irqsave(&freezer_delta_lock, flags);
 283        if (!freezer_delta.tv64 || (delta.tv64 < freezer_delta.tv64))
 284                freezer_delta = delta;
 285        spin_unlock_irqrestore(&freezer_delta_lock, flags);
 286}
 287
 288
 289/**
 290 * alarm_init - Initialize an alarm structure
 291 * @alarm: ptr to alarm to be initialized
 292 * @type: the type of the alarm
 293 * @function: callback that is run when the alarm fires
 294 */
 295void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
 296                enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
 297{
 298        timerqueue_init(&alarm->node);
 299        hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid,
 300                        HRTIMER_MODE_ABS);
 301        alarm->timer.function = alarmtimer_fired;
 302        alarm->function = function;
 303        alarm->type = type;
 304        alarm->state = ALARMTIMER_STATE_INACTIVE;
 305}
 306
 307/**
 308 * alarm_start - Sets an alarm to fire
 309 * @alarm: ptr to alarm to set
 310 * @start: time to run the alarm
 311 */
 312int alarm_start(struct alarm *alarm, ktime_t start)
 313{
 314        struct alarm_base *base = &alarm_bases[alarm->type];
 315        unsigned long flags;
 316        int ret;
 317
 318        spin_lock_irqsave(&base->lock, flags);
 319        alarm->node.expires = start;
 320        alarmtimer_enqueue(base, alarm);
 321        ret = hrtimer_start(&alarm->timer, alarm->node.expires,
 322                                HRTIMER_MODE_ABS);
 323        spin_unlock_irqrestore(&base->lock, flags);
 324        return ret;
 325}
 326
 327/**
 328 * alarm_try_to_cancel - Tries to cancel an alarm timer
 329 * @alarm: ptr to alarm to be canceled
 330 *
 331 * Returns 1 if the timer was canceled, 0 if it was not running,
 332 * and -1 if the callback was running
 333 */
 334int alarm_try_to_cancel(struct alarm *alarm)
 335{
 336        struct alarm_base *base = &alarm_bases[alarm->type];
 337        unsigned long flags;
 338        int ret;
 339
 340        spin_lock_irqsave(&base->lock, flags);
 341        ret = hrtimer_try_to_cancel(&alarm->timer);
 342        if (ret >= 0)
 343                alarmtimer_dequeue(base, alarm);
 344        spin_unlock_irqrestore(&base->lock, flags);
 345        return ret;
 346}
 347
 348
 349/**
 350 * alarm_cancel - Spins trying to cancel an alarm timer until it is done
 351 * @alarm: ptr to alarm to be canceled
 352 *
 353 * Returns 1 if the timer was canceled, 0 if it was not active.
 354 */
 355int alarm_cancel(struct alarm *alarm)
 356{
 357        for (;;) {
 358                int ret = alarm_try_to_cancel(alarm);
 359                if (ret >= 0)
 360                        return ret;
 361                cpu_relax();
 362        }
 363}
 364
 365
 366u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
 367{
 368        u64 overrun = 1;
 369        ktime_t delta;
 370
 371        delta = ktime_sub(now, alarm->node.expires);
 372
 373        if (delta.tv64 < 0)
 374                return 0;
 375
 376        if (unlikely(delta.tv64 >= interval.tv64)) {
 377                s64 incr = ktime_to_ns(interval);
 378
 379                overrun = ktime_divns(delta, incr);
 380
 381                alarm->node.expires = ktime_add_ns(alarm->node.expires,
 382                                                        incr*overrun);
 383
 384                if (alarm->node.expires.tv64 > now.tv64)
 385                        return overrun;
 386                /*
 387                 * This (and the ktime_add() below) is the
 388                 * correction for exact:
 389                 */
 390                overrun++;
 391        }
 392
 393        alarm->node.expires = ktime_add(alarm->node.expires, interval);
 394        return overrun;
 395}
 396
 397
 398
 399
 400/**
 401 * clock2alarm - helper that converts from clockid to alarmtypes
 402 * @clockid: clockid.
 403 */
 404static enum alarmtimer_type clock2alarm(clockid_t clockid)
 405{
 406        if (clockid == CLOCK_REALTIME_ALARM)
 407                return ALARM_REALTIME;
 408        if (clockid == CLOCK_BOOTTIME_ALARM)
 409                return ALARM_BOOTTIME;
 410        return -1;
 411}
 412
 413/**
 414 * alarm_handle_timer - Callback for posix timers
 415 * @alarm: alarm that fired
 416 *
 417 * Posix timer callback for expired alarm timers.
 418 */
 419static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
 420                                                        ktime_t now)
 421{
 422        struct k_itimer *ptr = container_of(alarm, struct k_itimer,
 423                                                it.alarm.alarmtimer);
 424        if (posix_timer_event(ptr, 0) != 0)
 425                ptr->it_overrun++;
 426
 427        /* Re-add periodic timers */
 428        if (ptr->it.alarm.interval.tv64) {
 429                ptr->it_overrun += alarm_forward(alarm, now,
 430                                                ptr->it.alarm.interval);
 431                return ALARMTIMER_RESTART;
 432        }
 433        return ALARMTIMER_NORESTART;
 434}
 435
 436/**
 437 * alarm_clock_getres - posix getres interface
 438 * @which_clock: clockid
 439 * @tp: timespec to fill
 440 *
 441 * Returns the granularity of underlying alarm base clock
 442 */
 443static int alarm_clock_getres(const clockid_t which_clock, struct timespec *tp)
 444{
 445        clockid_t baseid = alarm_bases[clock2alarm(which_clock)].base_clockid;
 446
 447        if (!alarmtimer_get_rtcdev())
 448                return -ENOTSUPP;
 449
 450        return hrtimer_get_res(baseid, tp);
 451}
 452
 453/**
 454 * alarm_clock_get - posix clock_get interface
 455 * @which_clock: clockid
 456 * @tp: timespec to fill.
 457 *
 458 * Provides the underlying alarm base time.
 459 */
 460static int alarm_clock_get(clockid_t which_clock, struct timespec *tp)
 461{
 462        struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
 463
 464        if (!alarmtimer_get_rtcdev())
 465                return -ENOTSUPP;
 466
 467        *tp = ktime_to_timespec(base->gettime());
 468        return 0;
 469}
 470
 471/**
 472 * alarm_timer_create - posix timer_create interface
 473 * @new_timer: k_itimer pointer to manage
 474 *
 475 * Initializes the k_itimer structure.
 476 */
 477static int alarm_timer_create(struct k_itimer *new_timer)
 478{
 479        enum  alarmtimer_type type;
 480        struct alarm_base *base;
 481
 482        if (!alarmtimer_get_rtcdev())
 483                return -ENOTSUPP;
 484
 485        if (!capable(CAP_WAKE_ALARM))
 486                return -EPERM;
 487
 488        type = clock2alarm(new_timer->it_clock);
 489        base = &alarm_bases[type];
 490        alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
 491        return 0;
 492}
 493
 494/**
 495 * alarm_timer_get - posix timer_get interface
 496 * @new_timer: k_itimer pointer
 497 * @cur_setting: itimerspec data to fill
 498 *
 499 * Copies the itimerspec data out from the k_itimer
 500 */
 501static void alarm_timer_get(struct k_itimer *timr,
 502                                struct itimerspec *cur_setting)
 503{
 504        memset(cur_setting, 0, sizeof(struct itimerspec));
 505
 506        cur_setting->it_interval =
 507                        ktime_to_timespec(timr->it.alarm.interval);
 508        cur_setting->it_value =
 509                ktime_to_timespec(timr->it.alarm.alarmtimer.node.expires);
 510        return;
 511}
 512
 513/**
 514 * alarm_timer_del - posix timer_del interface
 515 * @timr: k_itimer pointer to be deleted
 516 *
 517 * Cancels any programmed alarms for the given timer.
 518 */
 519static int alarm_timer_del(struct k_itimer *timr)
 520{
 521        if (!rtcdev)
 522                return -ENOTSUPP;
 523
 524        if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
 525                return TIMER_RETRY;
 526
 527        return 0;
 528}
 529
 530/**
 531 * alarm_timer_set - posix timer_set interface
 532 * @timr: k_itimer pointer to be deleted
 533 * @flags: timer flags
 534 * @new_setting: itimerspec to be used
 535 * @old_setting: itimerspec being replaced
 536 *
 537 * Sets the timer to new_setting, and starts the timer.
 538 */
 539static int alarm_timer_set(struct k_itimer *timr, int flags,
 540                                struct itimerspec *new_setting,
 541                                struct itimerspec *old_setting)
 542{
 543        if (!rtcdev)
 544                return -ENOTSUPP;
 545
 546        if (old_setting)
 547                alarm_timer_get(timr, old_setting);
 548
 549        /* If the timer was already set, cancel it */
 550        if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
 551                return TIMER_RETRY;
 552
 553        /* start the timer */
 554        timr->it.alarm.interval = timespec_to_ktime(new_setting->it_interval);
 555        alarm_start(&timr->it.alarm.alarmtimer,
 556                        timespec_to_ktime(new_setting->it_value));
 557        return 0;
 558}
 559
 560/**
 561 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
 562 * @alarm: ptr to alarm that fired
 563 *
 564 * Wakes up the task that set the alarmtimer
 565 */
 566static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
 567                                                                ktime_t now)
 568{
 569        struct task_struct *task = (struct task_struct *)alarm->data;
 570
 571        alarm->data = NULL;
 572        if (task)
 573                wake_up_process(task);
 574        return ALARMTIMER_NORESTART;
 575}
 576
 577/**
 578 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
 579 * @alarm: ptr to alarmtimer
 580 * @absexp: absolute expiration time
 581 *
 582 * Sets the alarm timer and sleeps until it is fired or interrupted.
 583 */
 584static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp)
 585{
 586        alarm->data = (void *)current;
 587        do {
 588                set_current_state(TASK_INTERRUPTIBLE);
 589                alarm_start(alarm, absexp);
 590                if (likely(alarm->data))
 591                        schedule();
 592
 593                alarm_cancel(alarm);
 594        } while (alarm->data && !signal_pending(current));
 595
 596        __set_current_state(TASK_RUNNING);
 597
 598        return (alarm->data == NULL);
 599}
 600
 601
 602/**
 603 * update_rmtp - Update remaining timespec value
 604 * @exp: expiration time
 605 * @type: timer type
 606 * @rmtp: user pointer to remaining timepsec value
 607 *
 608 * Helper function that fills in rmtp value with time between
 609 * now and the exp value
 610 */
 611static int update_rmtp(ktime_t exp, enum  alarmtimer_type type,
 612                        struct timespec __user *rmtp)
 613{
 614        struct timespec rmt;
 615        ktime_t rem;
 616
 617        rem = ktime_sub(exp, alarm_bases[type].gettime());
 618
 619        if (rem.tv64 <= 0)
 620                return 0;
 621        rmt = ktime_to_timespec(rem);
 622
 623        if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
 624                return -EFAULT;
 625
 626        return 1;
 627
 628}
 629
 630/**
 631 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
 632 * @restart: ptr to restart block
 633 *
 634 * Handles restarted clock_nanosleep calls
 635 */
 636static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
 637{
 638        enum  alarmtimer_type type = restart->nanosleep.clockid;
 639        ktime_t exp;
 640        struct timespec __user  *rmtp;
 641        struct alarm alarm;
 642        int ret = 0;
 643
 644        exp.tv64 = restart->nanosleep.expires;
 645        alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
 646
 647        if (alarmtimer_do_nsleep(&alarm, exp))
 648                goto out;
 649
 650        if (freezing(current))
 651                alarmtimer_freezerset(exp, type);
 652
 653        rmtp = restart->nanosleep.rmtp;
 654        if (rmtp) {
 655                ret = update_rmtp(exp, type, rmtp);
 656                if (ret <= 0)
 657                        goto out;
 658        }
 659
 660
 661        /* The other values in restart are already filled in */
 662        ret = -ERESTART_RESTARTBLOCK;
 663out:
 664        return ret;
 665}
 666
 667/**
 668 * alarm_timer_nsleep - alarmtimer nanosleep
 669 * @which_clock: clockid
 670 * @flags: determins abstime or relative
 671 * @tsreq: requested sleep time (abs or rel)
 672 * @rmtp: remaining sleep time saved
 673 *
 674 * Handles clock_nanosleep calls against _ALARM clockids
 675 */
 676static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
 677                     struct timespec *tsreq, struct timespec __user *rmtp)
 678{
 679        enum  alarmtimer_type type = clock2alarm(which_clock);
 680        struct alarm alarm;
 681        ktime_t exp;
 682        int ret = 0;
 683        struct restart_block *restart;
 684
 685        if (!alarmtimer_get_rtcdev())
 686                return -ENOTSUPP;
 687
 688        if (!capable(CAP_WAKE_ALARM))
 689                return -EPERM;
 690
 691        alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
 692
 693        exp = timespec_to_ktime(*tsreq);
 694        /* Convert (if necessary) to absolute time */
 695        if (flags != TIMER_ABSTIME) {
 696                ktime_t now = alarm_bases[type].gettime();
 697                exp = ktime_add(now, exp);
 698        }
 699
 700        if (alarmtimer_do_nsleep(&alarm, exp))
 701                goto out;
 702
 703        if (freezing(current))
 704                alarmtimer_freezerset(exp, type);
 705
 706        /* abs timers don't set remaining time or restart */
 707        if (flags == TIMER_ABSTIME) {
 708                ret = -ERESTARTNOHAND;
 709                goto out;
 710        }
 711
 712        if (rmtp) {
 713                ret = update_rmtp(exp, type, rmtp);
 714                if (ret <= 0)
 715                        goto out;
 716        }
 717
 718        restart = &current_thread_info()->restart_block;
 719        restart->fn = alarm_timer_nsleep_restart;
 720        restart->nanosleep.clockid = type;
 721        restart->nanosleep.expires = exp.tv64;
 722        restart->nanosleep.rmtp = rmtp;
 723        ret = -ERESTART_RESTARTBLOCK;
 724
 725out:
 726        return ret;
 727}
 728
 729
 730/* Suspend hook structures */
 731static const struct dev_pm_ops alarmtimer_pm_ops = {
 732        .suspend = alarmtimer_suspend,
 733};
 734
 735static struct platform_driver alarmtimer_driver = {
 736        .driver = {
 737                .name = "alarmtimer",
 738                .pm = &alarmtimer_pm_ops,
 739        }
 740};
 741
 742/**
 743 * alarmtimer_init - Initialize alarm timer code
 744 *
 745 * This function initializes the alarm bases and registers
 746 * the posix clock ids.
 747 */
 748static int __init alarmtimer_init(void)
 749{
 750        struct platform_device *pdev;
 751        int error = 0;
 752        int i;
 753        struct k_clock alarm_clock = {
 754                .clock_getres   = alarm_clock_getres,
 755                .clock_get      = alarm_clock_get,
 756                .timer_create   = alarm_timer_create,
 757                .timer_set      = alarm_timer_set,
 758                .timer_del      = alarm_timer_del,
 759                .timer_get      = alarm_timer_get,
 760                .nsleep         = alarm_timer_nsleep,
 761        };
 762
 763        alarmtimer_rtc_timer_init();
 764
 765        posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock);
 766        posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock);
 767
 768        /* Initialize alarm bases */
 769        alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
 770        alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
 771        alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
 772        alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
 773        for (i = 0; i < ALARM_NUMTYPE; i++) {
 774                timerqueue_init_head(&alarm_bases[i].timerqueue);
 775                spin_lock_init(&alarm_bases[i].lock);
 776        }
 777
 778        error = alarmtimer_rtc_interface_setup();
 779        if (error)
 780                return error;
 781
 782        error = platform_driver_register(&alarmtimer_driver);
 783        if (error)
 784                goto out_if;
 785
 786        pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
 787        if (IS_ERR(pdev)) {
 788                error = PTR_ERR(pdev);
 789                goto out_drv;
 790        }
 791        ws = wakeup_source_register("alarmtimer");
 792        return 0;
 793
 794out_drv:
 795        platform_driver_unregister(&alarmtimer_driver);
 796out_if:
 797        alarmtimer_rtc_interface_remove();
 798        return error;
 799}
 800device_initcall(alarmtimer_init);
 801
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