kernel/time/alarmtimer.c

   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  */
  37 static 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 */
  46 static ktime_t freezer_delta;
  47 static DEFINE_SPINLOCK(freezer_delta_lock);
  48
  49 #ifdef CONFIG_RTC_CLASS
  50 /* rtc timer and device for setting alarm wakeups at suspend */
  51 static struct rtc_timer         rtctimer;
  52 static struct rtc_device        *rtcdev;
  53 static 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  */
  62 struct 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
  75 static 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
  99 static inline void alarmtimer_rtc_timer_init(void)
 100 {
 101         rtc_timer_init(&rtctimer, NULL, NULL);
 102 }
 103
 104 static struct class_interface alarmtimer_rtc_interface = {
 105         .add_dev = &alarmtimer_rtc_add_device,
 106 };
 107
 108 static int alarmtimer_rtc_interface_setup(void)
 109 {
 110         alarmtimer_rtc_interface.class = rtc_class;
 111         return class_interface_register(&alarmtimer_rtc_interface);
 112 }
 113 static void alarmtimer_rtc_interface_remove(void)
 114 {
 115         class_interface_unregister(&alarmtimer_rtc_interface);
 116 }
 117 #else
 118 struct rtc_device *alarmtimer_get_rtcdev(void)
 119 {
 120         return NULL;
 121 }
 122 #define rtcdev (NULL)
 123 static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
 124 static inline void alarmtimer_rtc_interface_remove(void) { }
 125 static 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  */
 138 static 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  */
 160 static 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  */
 189 static 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  */
 246 static 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
 296 static int alarmtimer_suspend(struct device *dev)
 297 {
 298         return 0;
 299 }
 300 #endif
 301
 302 static 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  */
 323 void 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  */
 337 void 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  */
 357 int 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;
 372 out:
 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  */
 384 int 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
 395 u64 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  */
 433 static 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  */
 448 static 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  */
 472 static 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  */
 489 static 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  */
 506 static 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  */
 530 static 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  */
 548 static 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  */
 568 static 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  */
 595 static 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  */
 613 static 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  */
 640 static 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  */
 665 static 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;
 692 out:
 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  */
 705 static 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
 754 out:
 755         return ret;
 756 }
 757
 758
 759 /* Suspend hook structures */
 760 static const struct dev_pm_ops alarmtimer_pm_ops = {
 761         .suspend = alarmtimer_suspend,
 762 };
 763
 764 static 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  */
 777 static 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
 826 out_drv:
 827         platform_driver_unregister(&alarmtimer_driver);
 828 out_if:
 829         alarmtimer_rtc_interface_remove();
 830         return error;
 831 }
 832 device_initcall(alarmtimer_init);