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        struct hrtimer          timer;
  41        ktime_t                 (*gettime)(void);
  42        clockid_t               base_clockid;
  43} alarm_bases[ALARM_NUMTYPE];
  44
  45/* freezer delta & lock used to handle clock_nanosleep triggered wakeups */
  46static ktime_t freezer_delta;
  47static DEFINE_SPINLOCK(freezer_delta_lock);
  48
  49#ifdef CONFIG_RTC_CLASS
  50/* rtc timer and device for setting alarm wakeups at suspend */
  51static struct rtc_timer         rtctimer;
  52static struct rtc_device        *rtcdev;
  53static DEFINE_SPINLOCK(rtcdev_lock);
  54
  55/**
  56 * alarmtimer_get_rtcdev - Return selected rtcdevice
  57 *
  58 * This function returns the rtc device to use for wakealarms.
  59 * If one has not already been chosen, it checks to see if a
  60 * functional rtc device is available.
  61 */
  62struct rtc_device *alarmtimer_get_rtcdev(void)
  63{
  64        unsigned long flags;
  65        struct rtc_device *ret;
  66
  67        spin_lock_irqsave(&rtcdev_lock, flags);
  68        ret = rtcdev;
  69        spin_unlock_irqrestore(&rtcdev_lock, flags);
  70
  71        return ret;
  72}
  73
  74
  75static int alarmtimer_rtc_add_device(struct device *dev,
  76                                struct class_interface *class_intf)
  77{
  78        unsigned long flags;
  79        struct rtc_device *rtc = to_rtc_device(dev);
  80
  81        if (rtcdev)
  82                return -EBUSY;
  83
  84        if (!rtc->ops->set_alarm)
  85                return -1;
  86        if (!device_may_wakeup(rtc->dev.parent))
  87                return -1;
  88
  89        spin_lock_irqsave(&rtcdev_lock, flags);
  90        if (!rtcdev) {
  91                rtcdev = rtc;
  92                /* hold a reference so it doesn't go away */
  93                get_device(dev);
  94        }
  95        spin_unlock_irqrestore(&rtcdev_lock, flags);
  96        return 0;
  97}
  98
  99static inline void alarmtimer_rtc_timer_init(void)
 100{
 101        rtc_timer_init(&rtctimer, NULL, NULL);
 102}
 103
 104static struct class_interface alarmtimer_rtc_interface = {
 105        .add_dev = &alarmtimer_rtc_add_device,
 106};
 107
 108static int alarmtimer_rtc_interface_setup(void)
 109{
 110        alarmtimer_rtc_interface.class = rtc_class;
 111        return class_interface_register(&alarmtimer_rtc_interface);
 112}
 113static void alarmtimer_rtc_interface_remove(void)
 114{
 115        class_interface_unregister(&alarmtimer_rtc_interface);
 116}
 117#else
 118struct rtc_device *alarmtimer_get_rtcdev(void)
 119{
 120        return NULL;
 121}
 122#define rtcdev (NULL)
 123static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
 124static inline void alarmtimer_rtc_interface_remove(void) { }
 125static inline void alarmtimer_rtc_timer_init(void) { }
 126#endif
 127
 128/**
 129 * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
 130 * @base: pointer to the base where the timer is being run
 131 * @alarm: pointer to alarm being enqueued.
 132 *
 133 * Adds alarm to a alarm_base timerqueue and if necessary sets
 134 * an hrtimer to run.
 135 *
 136 * Must hold base->lock when calling.
 137 */
 138static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
 139{
 140        timerqueue_add(&base->timerqueue, &alarm->node);
 141        alarm->state |= ALARMTIMER_STATE_ENQUEUED;
 142
 143        if (&alarm->node == timerqueue_getnext(&base->timerqueue)) {
 144                hrtimer_try_to_cancel(&base->timer);
 145                hrtimer_start(&base->timer, alarm->node.expires,
 146                                HRTIMER_MODE_ABS);
 147        }
 148}
 149
 150/**
 151 * alarmtimer_remove - Removes an alarm timer from an alarm_base timerqueue
 152 * @base: pointer to the base where the timer is running
 153 * @alarm: pointer to alarm being removed
 154 *
 155 * Removes alarm to a alarm_base timerqueue and if necessary sets
 156 * a new timer to run.
 157 *
 158 * Must hold base->lock when calling.
 159 */
 160static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm)
 161{
 162        struct timerqueue_node *next = timerqueue_getnext(&base->timerqueue);
 163
 164        if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
 165                return;
 166
 167        timerqueue_del(&base->timerqueue, &alarm->node);
 168        alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
 169
 170        if (next == &alarm->node) {
 171                hrtimer_try_to_cancel(&base->timer);
 172                next = timerqueue_getnext(&base->timerqueue);
 173                if (!next)
 174                        return;
 175                hrtimer_start(&base->timer, next->expires, HRTIMER_MODE_ABS);
 176        }
 177}
 178
 179
 180/**
 181 * alarmtimer_fired - Handles alarm hrtimer being fired.
 182 * @timer: pointer to hrtimer being run
 183 *
 184 * When a alarm timer fires, this runs through the timerqueue to
 185 * see which alarms expired, and runs those. If there are more alarm
 186 * timers queued for the future, we set the hrtimer to fire when
 187 * when the next future alarm timer expires.
 188 */
 189static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
 190{
 191        struct alarm_base *base = container_of(timer, struct alarm_base, timer);
 192        struct timerqueue_node *next;
 193        unsigned long flags;
 194        ktime_t now;
 195        int ret = HRTIMER_NORESTART;
 196        int restart = ALARMTIMER_NORESTART;
 197
 198        spin_lock_irqsave(&base->lock, flags);
 199        now = base->gettime();
 200        while ((next = timerqueue_getnext(&base->timerqueue))) {
 201                struct alarm *alarm;
 202                ktime_t expired = next->expires;
 203
 204                if (expired.tv64 > now.tv64)
 205                        break;
 206
 207                alarm = container_of(next, struct alarm, node);
 208
 209                timerqueue_del(&base->timerqueue, &alarm->node);
 210                alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
 211
 212                alarm->state |= ALARMTIMER_STATE_CALLBACK;
 213                spin_unlock_irqrestore(&base->lock, flags);
 214                if (alarm->function)
 215                        restart = alarm->function(alarm, now);
 216                spin_lock_irqsave(&base->lock, flags);
 217                alarm->state &= ~ALARMTIMER_STATE_CALLBACK;
 218
 219                if (restart != ALARMTIMER_NORESTART) {
 220                        timerqueue_add(&base->timerqueue, &alarm->node);
 221                        alarm->state |= ALARMTIMER_STATE_ENQUEUED;
 222                }
 223        }
 224
 225        if (next) {
 226                hrtimer_set_expires(&base->timer, next->expires);
 227                ret = HRTIMER_RESTART;
 228        }
 229        spin_unlock_irqrestore(&base->lock, flags);
 230
 231        return ret;
 232
 233}
 234
 235#ifdef CONFIG_RTC_CLASS
 236/**
 237 * alarmtimer_suspend - Suspend time callback
 238 * @dev: unused
 239 * @state: unused
 240 *
 241 * When we are going into suspend, we look through the bases
 242 * to see which is the soonest timer to expire. We then
 243 * set an rtc timer to fire that far into the future, which
 244 * will wake us from suspend.
 245 */
 246static int alarmtimer_suspend(struct device *dev)
 247{
 248        struct rtc_time tm;
 249        ktime_t min, now;
 250        unsigned long flags;
 251        struct rtc_device *rtc;
 252        int i;
 253
 254        spin_lock_irqsave(&freezer_delta_lock, flags);
 255        min = freezer_delta;
 256        freezer_delta = ktime_set(0, 0);
 257        spin_unlock_irqrestore(&freezer_delta_lock, flags);
 258
 259        rtc = alarmtimer_get_rtcdev();
 260        /* If we have no rtcdev, just return */
 261        if (!rtc)
 262                return 0;
 263
 264        /* Find the soonest timer to expire*/
 265        for (i = 0; i < ALARM_NUMTYPE; i++) {
 266                struct alarm_base *base = &alarm_bases[i];
 267                struct timerqueue_node *next;
 268                ktime_t delta;
 269
 270                spin_lock_irqsave(&base->lock, flags);
 271                next = timerqueue_getnext(&base->timerqueue);
 272                spin_unlock_irqrestore(&base->lock, flags);
 273                if (!next)
 274                        continue;
 275                delta = ktime_sub(next->expires, base->gettime());
 276                if (!min.tv64 || (delta.tv64 < min.tv64))
 277                        min = delta;
 278        }
 279        if (min.tv64 == 0)
 280                return 0;
 281
 282        /* XXX - Should we enforce a minimum sleep time? */
 283        WARN_ON(min.tv64 < NSEC_PER_SEC);
 284
 285        /* Setup an rtc timer to fire that far in the future */
 286        rtc_timer_cancel(rtc, &rtctimer);
 287        rtc_read_time(rtc, &tm);
 288        now = rtc_tm_to_ktime(tm);
 289        now = ktime_add(now, min);
 290
 291        rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0));
 292
 293        return 0;
 294}
 295#else
 296static int alarmtimer_suspend(struct device *dev)
 297{
 298        return 0;
 299}
 300#endif
 301
 302static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
 303{
 304        ktime_t delta;
 305        unsigned long flags;
 306        struct alarm_base *base = &alarm_bases[type];
 307
 308        delta = ktime_sub(absexp, base->gettime());
 309
 310        spin_lock_irqsave(&freezer_delta_lock, flags);
 311        if (!freezer_delta.tv64 || (delta.tv64 < freezer_delta.tv64))
 312                freezer_delta = delta;
 313        spin_unlock_irqrestore(&freezer_delta_lock, flags);
 314}
 315
 316
 317/**
 318 * alarm_init - Initialize an alarm structure
 319 * @alarm: ptr to alarm to be initialized
 320 * @type: the type of the alarm
 321 * @function: callback that is run when the alarm fires
 322 */
 323void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
 324                enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
 325{
 326        timerqueue_init(&alarm->node);
 327        alarm->function = function;
 328        alarm->type = type;
 329        alarm->state = ALARMTIMER_STATE_INACTIVE;
 330}
 331
 332/**
 333 * alarm_start - Sets an alarm to fire
 334 * @alarm: ptr to alarm to set
 335 * @start: time to run the alarm
 336 */
 337void alarm_start(struct alarm *alarm, ktime_t start)
 338{
 339        struct alarm_base *base = &alarm_bases[alarm->type];
 340        unsigned long flags;
 341
 342        spin_lock_irqsave(&base->lock, flags);
 343        if (alarmtimer_active(alarm))
 344                alarmtimer_remove(base, alarm);
 345        alarm->node.expires = start;
 346        alarmtimer_enqueue(base, alarm);
 347        spin_unlock_irqrestore(&base->lock, flags);
 348}
 349
 350/**
 351 * alarm_try_to_cancel - Tries to cancel an alarm timer
 352 * @alarm: ptr to alarm to be canceled
 353 *
 354 * Returns 1 if the timer was canceled, 0 if it was not running,
 355 * and -1 if the callback was running
 356 */
 357int alarm_try_to_cancel(struct alarm *alarm)
 358{
 359        struct alarm_base *base = &alarm_bases[alarm->type];
 360        unsigned long flags;
 361        int ret = -1;
 362        spin_lock_irqsave(&base->lock, flags);
 363
 364        if (alarmtimer_callback_running(alarm))
 365                goto out;
 366
 367        if (alarmtimer_is_queued(alarm)) {
 368                alarmtimer_remove(base, alarm);
 369                ret = 1;
 370        } else
 371                ret = 0;
 372out:
 373        spin_unlock_irqrestore(&base->lock, flags);
 374        return ret;
 375}
 376
 377
 378/**
 379 * alarm_cancel - Spins trying to cancel an alarm timer until it is done
 380 * @alarm: ptr to alarm to be canceled
 381 *
 382 * Returns 1 if the timer was canceled, 0 if it was not active.
 383 */
 384int alarm_cancel(struct alarm *alarm)
 385{
 386        for (;;) {
 387                int ret = alarm_try_to_cancel(alarm);
 388                if (ret >= 0)
 389                        return ret;
 390                cpu_relax();
 391        }
 392}
 393
 394
 395u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
 396{
 397        u64 overrun = 1;
 398        ktime_t delta;
 399
 400        delta = ktime_sub(now, alarm->node.expires);
 401
 402        if (delta.tv64 < 0)
 403                return 0;
 404
 405        if (unlikely(delta.tv64 >= interval.tv64)) {
 406                s64 incr = ktime_to_ns(interval);
 407
 408                overrun = ktime_divns(delta, incr);
 409
 410                alarm->node.expires = ktime_add_ns(alarm->node.expires,
 411                                                        incr*overrun);
 412
 413                if (alarm->node.expires.tv64 > now.tv64)
 414                        return overrun;
 415                /*
 416                 * This (and the ktime_add() below) is the
 417                 * correction for exact:
 418                 */
 419                overrun++;
 420        }
 421
 422        alarm->node.expires = ktime_add(alarm->node.expires, interval);
 423        return overrun;
 424}
 425
 426
 427
 428
 429/**
 430 * clock2alarm - helper that converts from clockid to alarmtypes
 431 * @clockid: clockid.
 432 */
 433static enum alarmtimer_type clock2alarm(clockid_t clockid)
 434{
 435        if (clockid == CLOCK_REALTIME_ALARM)
 436                return ALARM_REALTIME;
 437        if (clockid == CLOCK_BOOTTIME_ALARM)
 438                return ALARM_BOOTTIME;
 439        return -1;
 440}
 441
 442/**
 443 * alarm_handle_timer - Callback for posix timers
 444 * @alarm: alarm that fired
 445 *
 446 * Posix timer callback for expired alarm timers.
 447 */
 448static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
 449                                                        ktime_t now)
 450{
 451        struct k_itimer *ptr = container_of(alarm, struct k_itimer,
 452                                                it.alarm.alarmtimer);
 453        if (posix_timer_event(ptr, 0) != 0)
 454                ptr->it_overrun++;
 455
 456        /* Re-add periodic timers */
 457        if (ptr->it.alarm.interval.tv64) {
 458                ptr->it_overrun += alarm_forward(alarm, now,
 459                                                ptr->it.alarm.interval);
 460                return ALARMTIMER_RESTART;
 461        }
 462        return ALARMTIMER_NORESTART;
 463}
 464
 465/**
 466 * alarm_clock_getres - posix getres interface
 467 * @which_clock: clockid
 468 * @tp: timespec to fill
 469 *
 470 * Returns the granularity of underlying alarm base clock
 471 */
 472static int alarm_clock_getres(const clockid_t which_clock, struct timespec *tp)
 473{
 474        clockid_t baseid = alarm_bases[clock2alarm(which_clock)].base_clockid;
 475
 476        if (!alarmtimer_get_rtcdev())
 477                return -ENOTSUPP;
 478
 479        return hrtimer_get_res(baseid, tp);
 480}
 481
 482/**
 483 * alarm_clock_get - posix clock_get interface
 484 * @which_clock: clockid
 485 * @tp: timespec to fill.
 486 *
 487 * Provides the underlying alarm base time.
 488 */
 489static int alarm_clock_get(clockid_t which_clock, struct timespec *tp)
 490{
 491        struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
 492
 493        if (!alarmtimer_get_rtcdev())
 494                return -ENOTSUPP;
 495
 496        *tp = ktime_to_timespec(base->gettime());
 497        return 0;
 498}
 499
 500/**
 501 * alarm_timer_create - posix timer_create interface
 502 * @new_timer: k_itimer pointer to manage
 503 *
 504 * Initializes the k_itimer structure.
 505 */
 506static int alarm_timer_create(struct k_itimer *new_timer)
 507{
 508        enum  alarmtimer_type type;
 509        struct alarm_base *base;
 510
 511        if (!alarmtimer_get_rtcdev())
 512                return -ENOTSUPP;
 513
 514        if (!capable(CAP_WAKE_ALARM))
 515                return -EPERM;
 516
 517        type = clock2alarm(new_timer->it_clock);
 518        base = &alarm_bases[type];
 519        alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
 520        return 0;
 521}
 522
 523/**
 524 * alarm_timer_get - posix timer_get interface
 525 * @new_timer: k_itimer pointer
 526 * @cur_setting: itimerspec data to fill
 527 *
 528 * Copies the itimerspec data out from the k_itimer
 529 */
 530static void alarm_timer_get(struct k_itimer *timr,
 531                                struct itimerspec *cur_setting)
 532{
 533        memset(cur_setting, 0, sizeof(struct itimerspec));
 534
 535        cur_setting->it_interval =
 536                        ktime_to_timespec(timr->it.alarm.interval);
 537        cur_setting->it_value =
 538                ktime_to_timespec(timr->it.alarm.alarmtimer.node.expires);
 539        return;
 540}
 541
 542/**
 543 * alarm_timer_del - posix timer_del interface
 544 * @timr: k_itimer pointer to be deleted
 545 *
 546 * Cancels any programmed alarms for the given timer.
 547 */
 548static int alarm_timer_del(struct k_itimer *timr)
 549{
 550        if (!rtcdev)
 551                return -ENOTSUPP;
 552
 553        if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
 554                return TIMER_RETRY;
 555
 556        return 0;
 557}
 558
 559/**
 560 * alarm_timer_set - posix timer_set interface
 561 * @timr: k_itimer pointer to be deleted
 562 * @flags: timer flags
 563 * @new_setting: itimerspec to be used
 564 * @old_setting: itimerspec being replaced
 565 *
 566 * Sets the timer to new_setting, and starts the timer.
 567 */
 568static int alarm_timer_set(struct k_itimer *timr, int flags,
 569                                struct itimerspec *new_setting,
 570                                struct itimerspec *old_setting)
 571{
 572        if (!rtcdev)
 573                return -ENOTSUPP;
 574
 575        if (old_setting)
 576                alarm_timer_get(timr, old_setting);
 577
 578        /* If the timer was already set, cancel it */
 579        if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
 580                return TIMER_RETRY;
 581
 582        /* start the timer */
 583        timr->it.alarm.interval = timespec_to_ktime(new_setting->it_interval);
 584        alarm_start(&timr->it.alarm.alarmtimer,
 585                        timespec_to_ktime(new_setting->it_value));
 586        return 0;
 587}
 588
 589/**
 590 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
 591 * @alarm: ptr to alarm that fired
 592 *
 593 * Wakes up the task that set the alarmtimer
 594 */
 595static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
 596                                                                ktime_t now)
 597{
 598        struct task_struct *task = (struct task_struct *)alarm->data;
 599
 600        alarm->data = NULL;
 601        if (task)
 602                wake_up_process(task);
 603        return ALARMTIMER_NORESTART;
 604}
 605
 606/**
 607 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
 608 * @alarm: ptr to alarmtimer
 609 * @absexp: absolute expiration time
 610 *
 611 * Sets the alarm timer and sleeps until it is fired or interrupted.
 612 */
 613static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp)
 614{
 615        alarm->data = (void *)current;
 616        do {
 617                set_current_state(TASK_INTERRUPTIBLE);
 618                alarm_start(alarm, absexp);
 619                if (likely(alarm->data))
 620                        schedule();
 621
 622                alarm_cancel(alarm);
 623        } while (alarm->data && !signal_pending(current));
 624
 625        __set_current_state(TASK_RUNNING);
 626
 627        return (alarm->data == NULL);
 628}
 629
 630
 631/**
 632 * update_rmtp - Update remaining timespec value
 633 * @exp: expiration time
 634 * @type: timer type
 635 * @rmtp: user pointer to remaining timepsec value
 636 *
 637 * Helper function that fills in rmtp value with time between
 638 * now and the exp value
 639 */
 640static int update_rmtp(ktime_t exp, enum  alarmtimer_type type,
 641                        struct timespec __user *rmtp)
 642{
 643        struct timespec rmt;
 644        ktime_t rem;
 645
 646        rem = ktime_sub(exp, alarm_bases[type].gettime());
 647
 648        if (rem.tv64 <= 0)
 649                return 0;
 650        rmt = ktime_to_timespec(rem);
 651
 652        if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
 653                return -EFAULT;
 654
 655        return 1;
 656
 657}
 658
 659/**
 660 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
 661 * @restart: ptr to restart block
 662 *
 663 * Handles restarted clock_nanosleep calls
 664 */
 665static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
 666{
 667        enum  alarmtimer_type type = restart->nanosleep.clockid;
 668        ktime_t exp;
 669        struct timespec __user  *rmtp;
 670        struct alarm alarm;
 671        int ret = 0;
 672
 673        exp.tv64 = restart->nanosleep.expires;
 674        alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
 675
 676        if (alarmtimer_do_nsleep(&alarm, exp))
 677                goto out;
 678
 679        if (freezing(current))
 680                alarmtimer_freezerset(exp, type);
 681
 682        rmtp = restart->nanosleep.rmtp;
 683        if (rmtp) {
 684                ret = update_rmtp(exp, type, rmtp);
 685                if (ret <= 0)
 686                        goto out;
 687        }
 688
 689
 690        /* The other values in restart are already filled in */
 691        ret = -ERESTART_RESTARTBLOCK;
 692out:
 693        return ret;
 694}
 695
 696/**
 697 * alarm_timer_nsleep - alarmtimer nanosleep
 698 * @which_clock: clockid
 699 * @flags: determins abstime or relative
 700 * @tsreq: requested sleep time (abs or rel)
 701 * @rmtp: remaining sleep time saved
 702 *
 703 * Handles clock_nanosleep calls against _ALARM clockids
 704 */
 705static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
 706                     struct timespec *tsreq, struct timespec __user *rmtp)
 707{
 708        enum  alarmtimer_type type = clock2alarm(which_clock);
 709        struct alarm alarm;
 710        ktime_t exp;
 711        int ret = 0;
 712        struct restart_block *restart;
 713
 714        if (!alarmtimer_get_rtcdev())
 715                return -ENOTSUPP;
 716
 717        if (!capable(CAP_WAKE_ALARM))
 718                return -EPERM;
 719
 720        alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
 721
 722        exp = timespec_to_ktime(*tsreq);
 723        /* Convert (if necessary) to absolute time */
 724        if (flags != TIMER_ABSTIME) {
 725                ktime_t now = alarm_bases[type].gettime();
 726                exp = ktime_add(now, exp);
 727        }
 728
 729        if (alarmtimer_do_nsleep(&alarm, exp))
 730                goto out;
 731
 732        if (freezing(current))
 733                alarmtimer_freezerset(exp, type);
 734
 735        /* abs timers don't set remaining time or restart */
 736        if (flags == TIMER_ABSTIME) {
 737                ret = -ERESTARTNOHAND;
 738                goto out;
 739        }
 740
 741        if (rmtp) {
 742                ret = update_rmtp(exp, type, rmtp);
 743                if (ret <= 0)
 744                        goto out;
 745        }
 746
 747        restart = &current_thread_info()->restart_block;
 748        restart->fn = alarm_timer_nsleep_restart;
 749        restart->nanosleep.clockid = type;
 750        restart->nanosleep.expires = exp.tv64;
 751        restart->nanosleep.rmtp = rmtp;
 752        ret = -ERESTART_RESTARTBLOCK;
 753
 754out:
 755        return ret;
 756}
 757
 758
 759/* Suspend hook structures */
 760static const struct dev_pm_ops alarmtimer_pm_ops = {
 761        .suspend = alarmtimer_suspend,
 762};
 763
 764static struct platform_driver alarmtimer_driver = {
 765        .driver = {
 766                .name = "alarmtimer",
 767                .pm = &alarmtimer_pm_ops,
 768        }
 769};
 770
 771/**
 772 * alarmtimer_init - Initialize alarm timer code
 773 *
 774 * This function initializes the alarm bases and registers
 775 * the posix clock ids.
 776 */
 777static int __init alarmtimer_init(void)
 778{
 779        struct platform_device *pdev;
 780        int error = 0;
 781        int i;
 782        struct k_clock alarm_clock = {
 783                .clock_getres   = alarm_clock_getres,
 784                .clock_get      = alarm_clock_get,
 785                .timer_create   = alarm_timer_create,
 786                .timer_set      = alarm_timer_set,
 787                .timer_del      = alarm_timer_del,
 788                .timer_get      = alarm_timer_get,
 789                .nsleep         = alarm_timer_nsleep,
 790        };
 791
 792        alarmtimer_rtc_timer_init();
 793
 794        posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock);
 795        posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock);
 796
 797        /* Initialize alarm bases */
 798        alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
 799        alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
 800        alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
 801        alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
 802        for (i = 0; i < ALARM_NUMTYPE; i++) {
 803                timerqueue_init_head(&alarm_bases[i].timerqueue);
 804                spin_lock_init(&alarm_bases[i].lock);
 805                hrtimer_init(&alarm_bases[i].timer,
 806                                alarm_bases[i].base_clockid,
 807                                HRTIMER_MODE_ABS);
 808                alarm_bases[i].timer.function = alarmtimer_fired;
 809        }
 810
 811        error = alarmtimer_rtc_interface_setup();
 812        if (error)
 813                return error;
 814
 815        error = platform_driver_register(&alarmtimer_driver);
 816        if (error)
 817                goto out_if;
 818
 819        pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
 820        if (IS_ERR(pdev)) {
 821                error = PTR_ERR(pdev);
 822                goto out_drv;
 823        }
 824        return 0;
 825
 826out_drv:
 827        platform_driver_unregister(&alarmtimer_driver);
 828out_if:
 829        alarmtimer_rtc_interface_remove();
 830        return error;
 831}
 832device_initcall(alarmtimer_init);
 833
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