drivers/base/power/wakeup.c

   1 /*
   2  * drivers/base/power/wakeup.c - System wakeup events framework
   3  *
   4  * Copyright (c) 2010 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
   5  *
   6  * This file is released under the GPLv2.
   7  */
   8
   9 #include <linux/device.h>
  10 #include <linux/slab.h>
  11 #include <linux/sched.h>
  12 #include <linux/capability.h>
  13 #include <linux/export.h>
  14 #include <linux/suspend.h>
  15 #include <linux/seq_file.h>
  16 #include <linux/debugfs.h>
  17 #include <trace/events/power.h>
  18
  19 #include "power.h"
  20
  21 /*
  22  * If set, the suspend/hibernate code will abort transitions to a sleep state
  23  * if wakeup events are registered during or immediately before the transition.
  24  */
  25 bool events_check_enabled __read_mostly;
  26
  27 /*
  28  * Combined counters of registered wakeup events and wakeup events in progress.
  29  * They need to be modified together atomically, so it's better to use one
  30  * atomic variable to hold them both.
  31  */
  32 static atomic_t combined_event_count = ATOMIC_INIT(0);
  33
  34 #define IN_PROGRESS_BITS        (sizeof(int) * 4)
  35 #define MAX_IN_PROGRESS         ((1 << IN_PROGRESS_BITS) - 1)
  36
  37 static void split_counters(unsigned int *cnt, unsigned int *inpr)
  38 {
  39         unsigned int comb = atomic_read(&combined_event_count);
  40
  41         *cnt = (comb >> IN_PROGRESS_BITS);
  42         *inpr = comb & MAX_IN_PROGRESS;
  43 }
  44
  45 /* A preserved old value of the events counter. */
  46 static unsigned int saved_count;
  47
  48 static DEFINE_SPINLOCK(events_lock);
  49
  50 static void pm_wakeup_timer_fn(unsigned long data);
  51
  52 static LIST_HEAD(wakeup_sources);
  53
  54 static DECLARE_WAIT_QUEUE_HEAD(wakeup_count_wait_queue);
  55
  56 /**
  57  * wakeup_source_prepare - Prepare a new wakeup source for initialization.
  58  * @ws: Wakeup source to prepare.
  59  * @name: Pointer to the name of the new wakeup source.
  60  *
  61  * Callers must ensure that the @name string won't be freed when @ws is still in
  62  * use.
  63  */
  64 void wakeup_source_prepare(struct wakeup_source *ws, const char *name)
  65 {
  66         if (ws) {
  67                 memset(ws, 0, sizeof(*ws));
  68                 ws->name = name;
  69         }
  70 }
  71 EXPORT_SYMBOL_GPL(wakeup_source_prepare);
  72
  73 /**
  74  * wakeup_source_create - Create a struct wakeup_source object.
  75  * @name: Name of the new wakeup source.
  76  */
  77 struct wakeup_source *wakeup_source_create(const char *name)
  78 {
  79         struct wakeup_source *ws;
  80
  81         ws = kmalloc(sizeof(*ws), GFP_KERNEL);
  82         if (!ws)
  83                 return NULL;
  84
  85         wakeup_source_prepare(ws, name ? kstrdup(name, GFP_KERNEL) : NULL);
  86         return ws;
  87 }
  88 EXPORT_SYMBOL_GPL(wakeup_source_create);
  89
  90 /**
  91  * wakeup_source_drop - Prepare a struct wakeup_source object for destruction.
  92  * @ws: Wakeup source to prepare for destruction.
  93  *
  94  * Callers must ensure that __pm_stay_awake() or __pm_wakeup_event() will never
  95  * be run in parallel with this function for the same wakeup source object.
  96  */
  97 void wakeup_source_drop(struct wakeup_source *ws)
  98 {
  99         if (!ws)
 100                 return;
 101
 102         del_timer_sync(&ws->timer);
 103         __pm_relax(ws);
 104 }
 105 EXPORT_SYMBOL_GPL(wakeup_source_drop);
 106
 107 /**
 108  * wakeup_source_destroy - Destroy a struct wakeup_source object.
 109  * @ws: Wakeup source to destroy.
 110  *
 111  * Use only for wakeup source objects created with wakeup_source_create().
 112  */
 113 void wakeup_source_destroy(struct wakeup_source *ws)
 114 {
 115         if (!ws)
 116                 return;
 117
 118         wakeup_source_drop(ws);
 119         kfree(ws->name);
 120         kfree(ws);
 121 }
 122 EXPORT_SYMBOL_GPL(wakeup_source_destroy);
 123
 124 /**
 125  * wakeup_source_add - Add given object to the list of wakeup sources.
 126  * @ws: Wakeup source object to add to the list.
 127  */
 128 void wakeup_source_add(struct wakeup_source *ws)
 129 {
 130         unsigned long flags;
 131
 132         if (WARN_ON(!ws))
 133                 return;
 134
 135         spin_lock_init(&ws->lock);
 136         setup_timer(&ws->timer, pm_wakeup_timer_fn, (unsigned long)ws);
 137         ws->active = false;
 138         ws->last_time = ktime_get();
 139
 140         spin_lock_irqsave(&events_lock, flags);
 141         list_add_rcu(&ws->entry, &wakeup_sources);
 142         spin_unlock_irqrestore(&events_lock, flags);
 143 }
 144 EXPORT_SYMBOL_GPL(wakeup_source_add);
 145
 146 /**
 147  * wakeup_source_remove - Remove given object from the wakeup sources list.
 148  * @ws: Wakeup source object to remove from the list.
 149  */
 150 void wakeup_source_remove(struct wakeup_source *ws)
 151 {
 152         unsigned long flags;
 153
 154         if (WARN_ON(!ws))
 155                 return;
 156
 157         spin_lock_irqsave(&events_lock, flags);
 158         list_del_rcu(&ws->entry);
 159         spin_unlock_irqrestore(&events_lock, flags);
 160         synchronize_rcu();
 161 }
 162 EXPORT_SYMBOL_GPL(wakeup_source_remove);
 163
 164 /**
 165  * wakeup_source_register - Create wakeup source and add it to the list.
 166  * @name: Name of the wakeup source to register.
 167  */
 168 struct wakeup_source *wakeup_source_register(const char *name)
 169 {
 170         struct wakeup_source *ws;
 171
 172         ws = wakeup_source_create(name);
 173         if (ws)
 174                 wakeup_source_add(ws);
 175
 176         return ws;
 177 }
 178 EXPORT_SYMBOL_GPL(wakeup_source_register);
 179
 180 /**
 181  * wakeup_source_unregister - Remove wakeup source from the list and remove it.
 182  * @ws: Wakeup source object to unregister.
 183  */
 184 void wakeup_source_unregister(struct wakeup_source *ws)
 185 {
 186         if (ws) {
 187                 wakeup_source_remove(ws);
 188                 wakeup_source_destroy(ws);
 189         }
 190 }
 191 EXPORT_SYMBOL_GPL(wakeup_source_unregister);
 192
 193 /**
 194  * device_wakeup_attach - Attach a wakeup source object to a device object.
 195  * @dev: Device to handle.
 196  * @ws: Wakeup source object to attach to @dev.
 197  *
 198  * This causes @dev to be treated as a wakeup device.
 199  */
 200 static int device_wakeup_attach(struct device *dev, struct wakeup_source *ws)
 201 {
 202         spin_lock_irq(&dev->power.lock);
 203         if (dev->power.wakeup) {
 204                 spin_unlock_irq(&dev->power.lock);
 205                 return -EEXIST;
 206         }
 207         dev->power.wakeup = ws;
 208         spin_unlock_irq(&dev->power.lock);
 209         return 0;
 210 }
 211
 212 /**
 213  * device_wakeup_enable - Enable given device to be a wakeup source.
 214  * @dev: Device to handle.
 215  *
 216  * Create a wakeup source object, register it and attach it to @dev.
 217  */
 218 int device_wakeup_enable(struct device *dev)
 219 {
 220         struct wakeup_source *ws;
 221         int ret;
 222
 223         if (!dev || !dev->power.can_wakeup)
 224                 return -EINVAL;
 225
 226         ws = wakeup_source_register(dev_name(dev));
 227         if (!ws)
 228                 return -ENOMEM;
 229
 230         ret = device_wakeup_attach(dev, ws);
 231         if (ret)
 232                 wakeup_source_unregister(ws);
 233
 234         return ret;
 235 }
 236 EXPORT_SYMBOL_GPL(device_wakeup_enable);
 237
 238 /**
 239  * device_wakeup_detach - Detach a device's wakeup source object from it.
 240  * @dev: Device to detach the wakeup source object from.
 241  *
 242  * After it returns, @dev will not be treated as a wakeup device any more.
 243  */
 244 static struct wakeup_source *device_wakeup_detach(struct device *dev)
 245 {
 246         struct wakeup_source *ws;
 247
 248         spin_lock_irq(&dev->power.lock);
 249         ws = dev->power.wakeup;
 250         dev->power.wakeup = NULL;
 251         spin_unlock_irq(&dev->power.lock);
 252         return ws;
 253 }
 254
 255 /**
 256  * device_wakeup_disable - Do not regard a device as a wakeup source any more.
 257  * @dev: Device to handle.
 258  *
 259  * Detach the @dev's wakeup source object from it, unregister this wakeup source
 260  * object and destroy it.
 261  */
 262 int device_wakeup_disable(struct device *dev)
 263 {
 264         struct wakeup_source *ws;
 265
 266         if (!dev || !dev->power.can_wakeup)
 267                 return -EINVAL;
 268
 269         ws = device_wakeup_detach(dev);
 270         if (ws)
 271                 wakeup_source_unregister(ws);
 272
 273         return 0;
 274 }
 275 EXPORT_SYMBOL_GPL(device_wakeup_disable);
 276
 277 /**
 278  * device_set_wakeup_capable - Set/reset device wakeup capability flag.
 279  * @dev: Device to handle.
 280  * @capable: Whether or not @dev is capable of waking up the system from sleep.
 281  *
 282  * If @capable is set, set the @dev's power.can_wakeup flag and add its
 283  * wakeup-related attributes to sysfs.  Otherwise, unset the @dev's
 284  * power.can_wakeup flag and remove its wakeup-related attributes from sysfs.
 285  *
 286  * This function may sleep and it can't be called from any context where
 287  * sleeping is not allowed.
 288  */
 289 void device_set_wakeup_capable(struct device *dev, bool capable)
 290 {
 291         if (!!dev->power.can_wakeup == !!capable)
 292                 return;
 293
 294         if (device_is_registered(dev) && !list_empty(&dev->power.entry)) {
 295                 if (capable) {
 296                         if (wakeup_sysfs_add(dev))
 297                                 return;
 298                 } else {
 299                         wakeup_sysfs_remove(dev);
 300                 }
 301         }
 302         dev->power.can_wakeup = capable;
 303 }
 304 EXPORT_SYMBOL_GPL(device_set_wakeup_capable);
 305
 306 /**
 307  * device_init_wakeup - Device wakeup initialization.
 308  * @dev: Device to handle.
 309  * @enable: Whether or not to enable @dev as a wakeup device.
 310  *
 311  * By default, most devices should leave wakeup disabled.  The exceptions are
 312  * devices that everyone expects to be wakeup sources: keyboards, power buttons,
 313  * possibly network interfaces, etc.  Also, devices that don't generate their
 314  * own wakeup requests but merely forward requests from one bus to another
 315  * (like PCI bridges) should have wakeup enabled by default.
 316  */
 317 int device_init_wakeup(struct device *dev, bool enable)
 318 {
 319         int ret = 0;
 320
 321         if (enable) {
 322                 device_set_wakeup_capable(dev, true);
 323                 ret = device_wakeup_enable(dev);
 324         } else {
 325                 device_set_wakeup_capable(dev, false);
 326         }
 327
 328         return ret;
 329 }
 330 EXPORT_SYMBOL_GPL(device_init_wakeup);
 331
 332 /**
 333  * device_set_wakeup_enable - Enable or disable a device to wake up the system.
 334  * @dev: Device to handle.
 335  */
 336 int device_set_wakeup_enable(struct device *dev, bool enable)
 337 {
 338         if (!dev || !dev->power.can_wakeup)
 339                 return -EINVAL;
 340
 341         return enable ? device_wakeup_enable(dev) : device_wakeup_disable(dev);
 342 }
 343 EXPORT_SYMBOL_GPL(device_set_wakeup_enable);
 344
 345 /*
 346  * The functions below use the observation that each wakeup event starts a
 347  * period in which the system should not be suspended.  The moment this period
 348  * will end depends on how the wakeup event is going to be processed after being
 349  * detected and all of the possible cases can be divided into two distinct
 350  * groups.
 351  *
 352  * First, a wakeup event may be detected by the same functional unit that will
 353  * carry out the entire processing of it and possibly will pass it to user space
 354  * for further processing.  In that case the functional unit that has detected
 355  * the event may later "close" the "no suspend" period associated with it
 356  * directly as soon as it has been dealt with.  The pair of pm_stay_awake() and
 357  * pm_relax(), balanced with each other, is supposed to be used in such
 358  * situations.
 359  *
 360  * Second, a wakeup event may be detected by one functional unit and processed
 361  * by another one.  In that case the unit that has detected it cannot really
 362  * "close" the "no suspend" period associated with it, unless it knows in
 363  * advance what's going to happen to the event during processing.  This
 364  * knowledge, however, may not be available to it, so it can simply specify time
 365  * to wait before the system can be suspended and pass it as the second
 366  * argument of pm_wakeup_event().
 367  *
 368  * It is valid to call pm_relax() after pm_wakeup_event(), in which case the
 369  * "no suspend" period will be ended either by the pm_relax(), or by the timer
 370  * function executed when the timer expires, whichever comes first.
 371  */
 372
 373 /**
 374  * wakup_source_activate - Mark given wakeup source as active.
 375  * @ws: Wakeup source to handle.
 376  *
 377  * Update the @ws' statistics and, if @ws has just been activated, notify the PM
 378  * core of the event by incrementing the counter of of wakeup events being
 379  * processed.
 380  */
 381 static void wakeup_source_activate(struct wakeup_source *ws)
 382 {
 383         unsigned int cec;
 384
 385         /*
 386          * active wakeup source should bring the system
 387          * out of PM_SUSPEND_FREEZE state
 388          */
 389         freeze_wake();
 390
 391         ws->active = true;
 392         ws->active_count++;
 393         ws->last_time = ktime_get();
 394         if (ws->autosleep_enabled)
 395                 ws->start_prevent_time = ws->last_time;
 396
 397         /* Increment the counter of events in progress. */
 398         cec = atomic_inc_return(&combined_event_count);
 399
 400         trace_wakeup_source_activate(ws->name, cec);
 401 }
 402
 403 /**
 404  * wakeup_source_report_event - Report wakeup event using the given source.
 405  * @ws: Wakeup source to report the event for.
 406  */
 407 static void wakeup_source_report_event(struct wakeup_source *ws)
 408 {
 409         ws->event_count++;
 410         /* This is racy, but the counter is approximate anyway. */
 411         if (events_check_enabled)
 412                 ws->wakeup_count++;
 413
 414         if (!ws->active)
 415                 wakeup_source_activate(ws);
 416 }
 417
 418 /**
 419  * __pm_stay_awake - Notify the PM core of a wakeup event.
 420  * @ws: Wakeup source object associated with the source of the event.
 421  *
 422  * It is safe to call this function from interrupt context.
 423  */
 424 void __pm_stay_awake(struct wakeup_source *ws)
 425 {
 426         unsigned long flags;
 427
 428         if (!ws)
 429                 return;
 430
 431         spin_lock_irqsave(&ws->lock, flags);
 432
 433         wakeup_source_report_event(ws);
 434         del_timer(&ws->timer);
 435         ws->timer_expires = 0;
 436
 437         spin_unlock_irqrestore(&ws->lock, flags);
 438 }
 439 EXPORT_SYMBOL_GPL(__pm_stay_awake);
 440
 441 /**
 442  * pm_stay_awake - Notify the PM core that a wakeup event is being processed.
 443  * @dev: Device the wakeup event is related to.
 444  *
 445  * Notify the PM core of a wakeup event (signaled by @dev) by calling
 446  * __pm_stay_awake for the @dev's wakeup source object.
 447  *
 448  * Call this function after detecting of a wakeup event if pm_relax() is going
 449  * to be called directly after processing the event (and possibly passing it to
 450  * user space for further processing).
 451  */
 452 void pm_stay_awake(struct device *dev)
 453 {
 454         unsigned long flags;
 455
 456         if (!dev)
 457                 return;
 458
 459         spin_lock_irqsave(&dev->power.lock, flags);
 460         __pm_stay_awake(dev->power.wakeup);
 461         spin_unlock_irqrestore(&dev->power.lock, flags);
 462 }
 463 EXPORT_SYMBOL_GPL(pm_stay_awake);
 464
 465 #ifdef CONFIG_PM_AUTOSLEEP
 466 static void update_prevent_sleep_time(struct wakeup_source *ws, ktime_t now)
 467 {
 468         ktime_t delta = ktime_sub(now, ws->start_prevent_time);
 469         ws->prevent_sleep_time = ktime_add(ws->prevent_sleep_time, delta);
 470 }
 471 #else
 472 static inline void update_prevent_sleep_time(struct wakeup_source *ws,
 473                                              ktime_t now) {}
 474 #endif
 475
 476 /**
 477  * wakup_source_deactivate - Mark given wakeup source as inactive.
 478  * @ws: Wakeup source to handle.
 479  *
 480  * Update the @ws' statistics and notify the PM core that the wakeup source has
 481  * become inactive by decrementing the counter of wakeup events being processed
 482  * and incrementing the counter of registered wakeup events.
 483  */
 484 static void wakeup_source_deactivate(struct wakeup_source *ws)
 485 {
 486         unsigned int cnt, inpr, cec;
 487         ktime_t duration;
 488         ktime_t now;
 489
 490         ws->relax_count++;
 491         /*
 492          * __pm_relax() may be called directly or from a timer function.
 493          * If it is called directly right after the timer function has been
 494          * started, but before the timer function calls __pm_relax(), it is
 495          * possible that __pm_stay_awake() will be called in the meantime and
 496          * will set ws->active.  Then, ws->active may be cleared immediately
 497          * by the __pm_relax() called from the timer function, but in such a
 498          * case ws->relax_count will be different from ws->active_count.
 499          */
 500         if (ws->relax_count != ws->active_count) {
 501                 ws->relax_count--;
 502                 return;
 503         }
 504
 505         ws->active = false;
 506
 507         now = ktime_get();
 508         duration = ktime_sub(now, ws->last_time);
 509         ws->total_time = ktime_add(ws->total_time, duration);
 510         if (ktime_to_ns(duration) > ktime_to_ns(ws->max_time))
 511                 ws->max_time = duration;
 512
 513         ws->last_time = now;
 514         del_timer(&ws->timer);
 515         ws->timer_expires = 0;
 516
 517         if (ws->autosleep_enabled)
 518                 update_prevent_sleep_time(ws, now);
 519
 520         /*
 521          * Increment the counter of registered wakeup events and decrement the
 522          * couter of wakeup events in progress simultaneously.
 523          */
 524         cec = atomic_add_return(MAX_IN_PROGRESS, &combined_event_count);
 525         trace_wakeup_source_deactivate(ws->name, cec);
 526
 527         split_counters(&cnt, &inpr);
 528         if (!inpr && waitqueue_active(&wakeup_count_wait_queue))
 529                 wake_up(&wakeup_count_wait_queue);
 530 }
 531
 532 /**
 533  * __pm_relax - Notify the PM core that processing of a wakeup event has ended.
 534  * @ws: Wakeup source object associated with the source of the event.
 535  *
 536  * Call this function for wakeup events whose processing started with calling
 537  * __pm_stay_awake().
 538  *
 539  * It is safe to call it from interrupt context.
 540  */
 541 void __pm_relax(struct wakeup_source *ws)
 542 {
 543         unsigned long flags;
 544
 545         if (!ws)
 546                 return;
 547
 548         spin_lock_irqsave(&ws->lock, flags);
 549         if (ws->active)
 550                 wakeup_source_deactivate(ws);
 551         spin_unlock_irqrestore(&ws->lock, flags);
 552 }
 553 EXPORT_SYMBOL_GPL(__pm_relax);
 554
 555 /**
 556  * pm_relax - Notify the PM core that processing of a wakeup event has ended.
 557  * @dev: Device that signaled the event.
 558  *
 559  * Execute __pm_relax() for the @dev's wakeup source object.
 560  */
 561 void pm_relax(struct device *dev)
 562 {
 563         unsigned long flags;
 564
 565         if (!dev)
 566                 return;
 567
 568         spin_lock_irqsave(&dev->power.lock, flags);
 569         __pm_relax(dev->power.wakeup);
 570         spin_unlock_irqrestore(&dev->power.lock, flags);
 571 }
 572 EXPORT_SYMBOL_GPL(pm_relax);
 573
 574 /**
 575  * pm_wakeup_timer_fn - Delayed finalization of a wakeup event.
 576  * @data: Address of the wakeup source object associated with the event source.
 577  *
 578  * Call wakeup_source_deactivate() for the wakeup source whose address is stored
 579  * in @data if it is currently active and its timer has not been canceled and
 580  * the expiration time of the timer is not in future.
 581  */
 582 static void pm_wakeup_timer_fn(unsigned long data)
 583 {
 584         struct wakeup_source *ws = (struct wakeup_source *)data;
 585         unsigned long flags;
 586
 587         spin_lock_irqsave(&ws->lock, flags);
 588
 589         if (ws->active && ws->timer_expires
 590             && time_after_eq(jiffies, ws->timer_expires)) {
 591                 wakeup_source_deactivate(ws);
 592                 ws->expire_count++;
 593         }
 594
 595         spin_unlock_irqrestore(&ws->lock, flags);
 596 }
 597
 598 /**
 599  * __pm_wakeup_event - Notify the PM core of a wakeup event.
 600  * @ws: Wakeup source object associated with the event source.
 601  * @msec: Anticipated event processing time (in milliseconds).
 602  *
 603  * Notify the PM core of a wakeup event whose source is @ws that will take
 604  * approximately @msec milliseconds to be processed by the kernel.  If @ws is
 605  * not active, activate it.  If @msec is nonzero, set up the @ws' timer to
 606  * execute pm_wakeup_timer_fn() in future.
 607  *
 608  * It is safe to call this function from interrupt context.
 609  */
 610 void __pm_wakeup_event(struct wakeup_source *ws, unsigned int msec)
 611 {
 612         unsigned long flags;
 613         unsigned long expires;
 614
 615         if (!ws)
 616                 return;
 617
 618         spin_lock_irqsave(&ws->lock, flags);
 619
 620         wakeup_source_report_event(ws);
 621
 622         if (!msec) {
 623                 wakeup_source_deactivate(ws);
 624                 goto unlock;
 625         }
 626
 627         expires = jiffies + msecs_to_jiffies(msec);
 628         if (!expires)
 629                 expires = 1;
 630
 631         if (!ws->timer_expires || time_after(expires, ws->timer_expires)) {
 632                 mod_timer(&ws->timer, expires);
 633                 ws->timer_expires = expires;
 634         }
 635
 636  unlock:
 637         spin_unlock_irqrestore(&ws->lock, flags);
 638 }
 639 EXPORT_SYMBOL_GPL(__pm_wakeup_event);
 640
 641
 642 /**
 643  * pm_wakeup_event - Notify the PM core of a wakeup event.
 644  * @dev: Device the wakeup event is related to.
 645  * @msec: Anticipated event processing time (in milliseconds).
 646  *
 647  * Call __pm_wakeup_event() for the @dev's wakeup source object.
 648  */
 649 void pm_wakeup_event(struct device *dev, unsigned int msec)
 650 {
 651         unsigned long flags;
 652
 653         if (!dev)
 654                 return;
 655
 656         spin_lock_irqsave(&dev->power.lock, flags);
 657         __pm_wakeup_event(dev->power.wakeup, msec);
 658         spin_unlock_irqrestore(&dev->power.lock, flags);
 659 }
 660 EXPORT_SYMBOL_GPL(pm_wakeup_event);
 661
 662 void pm_print_active_wakeup_sources(void)
 663 {
 664         struct wakeup_source *ws;
 665         int active = 0;
 666         struct wakeup_source *last_activity_ws = NULL;
 667
 668         rcu_read_lock();
 669         list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
 670                 if (ws->active) {
 671                         pr_info("active wakeup source: %s\n", ws->name);
 672                         active = 1;
 673                 } else if (!active &&
 674                            (!last_activity_ws ||
 675                             ktime_to_ns(ws->last_time) >
 676                             ktime_to_ns(last_activity_ws->last_time))) {
 677                         last_activity_ws = ws;
 678                 }
 679         }
 680
 681         if (!active && last_activity_ws)
 682                 pr_info("last active wakeup source: %s\n",
 683                         last_activity_ws->name);
 684         rcu_read_unlock();
 685 }
 686 EXPORT_SYMBOL_GPL(pm_print_active_wakeup_sources);
 687
 688 /**
 689  * pm_wakeup_pending - Check if power transition in progress should be aborted.
 690  *
 691  * Compare the current number of registered wakeup events with its preserved
 692  * value from the past and return true if new wakeup events have been registered
 693  * since the old value was stored.  Also return true if the current number of
 694  * wakeup events being processed is different from zero.
 695  */
 696 bool pm_wakeup_pending(void)
 697 {
 698         unsigned long flags;
 699         bool ret = false;
 700
 701         spin_lock_irqsave(&events_lock, flags);
 702         if (events_check_enabled) {
 703                 unsigned int cnt, inpr;
 704
 705                 split_counters(&cnt, &inpr);
 706                 ret = (cnt != saved_count || inpr > 0);
 707                 events_check_enabled = !ret;
 708         }
 709         spin_unlock_irqrestore(&events_lock, flags);
 710
 711         if (ret) {
 712                 pr_info("PM: Wakeup pending, aborting suspend\n");
 713                 pm_print_active_wakeup_sources();
 714         }
 715
 716         return ret;
 717 }
 718
 719 /**
 720  * pm_get_wakeup_count - Read the number of registered wakeup events.
 721  * @count: Address to store the value at.
 722  * @block: Whether or not to block.
 723  *
 724  * Store the number of registered wakeup events at the address in @count.  If
 725  * @block is set, block until the current number of wakeup events being
 726  * processed is zero.
 727  *
 728  * Return 'false' if the current number of wakeup events being processed is
 729  * nonzero.  Otherwise return 'true'.
 730  */
 731 bool pm_get_wakeup_count(unsigned int *count, bool block)
 732 {
 733         unsigned int cnt, inpr;
 734
 735         if (block) {
 736                 DEFINE_WAIT(wait);
 737
 738                 for (;;) {
 739                         prepare_to_wait(&wakeup_count_wait_queue, &wait,
 740                                         TASK_INTERRUPTIBLE);
 741                         split_counters(&cnt, &inpr);
 742                         if (inpr == 0 || signal_pending(current))
 743                                 break;
 744
 745                         schedule();
 746                 }
 747                 finish_wait(&wakeup_count_wait_queue, &wait);
 748         }
 749
 750         split_counters(&cnt, &inpr);
 751         *count = cnt;
 752         return !inpr;
 753 }
 754
 755 /**
 756  * pm_save_wakeup_count - Save the current number of registered wakeup events.
 757  * @count: Value to compare with the current number of registered wakeup events.
 758  *
 759  * If @count is equal to the current number of registered wakeup events and the
 760  * current number of wakeup events being processed is zero, store @count as the
 761  * old number of registered wakeup events for pm_check_wakeup_events(), enable
 762  * wakeup events detection and return 'true'.  Otherwise disable wakeup events
 763  * detection and return 'false'.
 764  */
 765 bool pm_save_wakeup_count(unsigned int count)
 766 {
 767         unsigned int cnt, inpr;
 768         unsigned long flags;
 769
 770         events_check_enabled = false;
 771         spin_lock_irqsave(&events_lock, flags);
 772         split_counters(&cnt, &inpr);
 773         if (cnt == count && inpr == 0) {
 774                 saved_count = count;
 775                 events_check_enabled = true;
 776         }
 777         spin_unlock_irqrestore(&events_lock, flags);
 778         return events_check_enabled;
 779 }
 780
 781 #ifdef CONFIG_PM_AUTOSLEEP
 782 /**
 783  * pm_wakep_autosleep_enabled - Modify autosleep_enabled for all wakeup sources.
 784  * @enabled: Whether to set or to clear the autosleep_enabled flags.
 785  */
 786 void pm_wakep_autosleep_enabled(bool set)
 787 {
 788         struct wakeup_source *ws;
 789         ktime_t now = ktime_get();
 790
 791         rcu_read_lock();
 792         list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
 793                 spin_lock_irq(&ws->lock);
 794                 if (ws->autosleep_enabled != set) {
 795                         ws->autosleep_enabled = set;
 796                         if (ws->active) {
 797                                 if (set)
 798                                         ws->start_prevent_time = now;
 799                                 else
 800                                         update_prevent_sleep_time(ws, now);
 801                         }
 802                 }
 803                 spin_unlock_irq(&ws->lock);
 804         }
 805         rcu_read_unlock();
 806 }
 807 #endif /* CONFIG_PM_AUTOSLEEP */
 808
 809 static struct dentry *wakeup_sources_stats_dentry;
 810
 811 /**
 812  * print_wakeup_source_stats - Print wakeup source statistics information.
 813  * @m: seq_file to print the statistics into.
 814  * @ws: Wakeup source object to print the statistics for.
 815  */
 816 static int print_wakeup_source_stats(struct seq_file *m,
 817                                      struct wakeup_source *ws)
 818 {
 819         unsigned long flags;
 820         ktime_t total_time;
 821         ktime_t max_time;
 822         unsigned long active_count;
 823         ktime_t active_time;
 824         ktime_t prevent_sleep_time;
 825         int ret;
 826
 827         spin_lock_irqsave(&ws->lock, flags);
 828
 829         total_time = ws->total_time;
 830         max_time = ws->max_time;
 831         prevent_sleep_time = ws->prevent_sleep_time;
 832         active_count = ws->active_count;
 833         if (ws->active) {
 834                 ktime_t now = ktime_get();
 835
 836                 active_time = ktime_sub(now, ws->last_time);
 837                 total_time = ktime_add(total_time, active_time);
 838                 if (active_time.tv64 > max_time.tv64)
 839                         max_time = active_time;
 840
 841                 if (ws->autosleep_enabled)
 842                         prevent_sleep_time = ktime_add(prevent_sleep_time,
 843                                 ktime_sub(now, ws->start_prevent_time));
 844         } else {
 845                 active_time = ktime_set(0, 0);
 846         }
 847
 848         ret = seq_printf(m, "%-12s\t%lu\t\t%lu\t\t%lu\t\t%lu\t\t"
 849                         "%lld\t\t%lld\t\t%lld\t\t%lld\t\t%lld\n",
 850                         ws->name, active_count, ws->event_count,
 851                         ws->wakeup_count, ws->expire_count,
 852                         ktime_to_ms(active_time), ktime_to_ms(total_time),
 853                         ktime_to_ms(max_time), ktime_to_ms(ws->last_time),
 854                         ktime_to_ms(prevent_sleep_time));
 855
 856         spin_unlock_irqrestore(&ws->lock, flags);
 857
 858         return ret;
 859 }
 860
 861 /**
 862  * wakeup_sources_stats_show - Print wakeup sources statistics information.
 863  * @m: seq_file to print the statistics into.
 864  */
 865 static int wakeup_sources_stats_show(struct seq_file *m, void *unused)
 866 {
 867         struct wakeup_source *ws;
 868
 869         seq_puts(m, "name\t\tactive_count\tevent_count\twakeup_count\t"
 870                 "expire_count\tactive_since\ttotal_time\tmax_time\t"
 871                 "last_change\tprevent_suspend_time\n");
 872
 873         rcu_read_lock();
 874         list_for_each_entry_rcu(ws, &wakeup_sources, entry)
 875                 print_wakeup_source_stats(m, ws);
 876         rcu_read_unlock();
 877
 878         return 0;
 879 }
 880
 881 static int wakeup_sources_stats_open(struct inode *inode, struct file *file)
 882 {
 883         return single_open(file, wakeup_sources_stats_show, NULL);
 884 }
 885
 886 static const struct file_operations wakeup_sources_stats_fops = {
 887         .owner = THIS_MODULE,
 888         .open = wakeup_sources_stats_open,
 889         .read = seq_read,
 890         .llseek = seq_lseek,
 891         .release = single_release,
 892 };
 893
 894 static int __init wakeup_sources_debugfs_init(void)
 895 {
 896         wakeup_sources_stats_dentry = debugfs_create_file("wakeup_sources",
 897                         S_IRUGO, NULL, NULL, &wakeup_sources_stats_fops);
 898         return 0;
 899 }
 900
 901 postcore_initcall(wakeup_sources_debugfs_init);