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 <linux/types.h>
  18 #include <trace/events/power.h>
  19
  20 #include "power.h"
  21
  22 /*
  23  * If set, the suspend/hibernate code will abort transitions to a sleep state
  24  * if wakeup events are registered during or immediately before the transition.
  25  */
  26 bool events_check_enabled __read_mostly;
  27
  28 /*
  29  * Combined counters of registered wakeup events and wakeup events in progress.
  30  * They need to be modified together atomically, so it's better to use one
  31  * atomic variable to hold them both.
  32  */
  33 static atomic_t combined_event_count = ATOMIC_INIT(0);
  34
  35 #define IN_PROGRESS_BITS        (sizeof(int) * 4)
  36 #define MAX_IN_PROGRESS         ((1 << IN_PROGRESS_BITS) - 1)
  37
  38 static void split_counters(unsigned int *cnt, unsigned int *inpr)
  39 {
  40         unsigned int comb = atomic_read(&combined_event_count);
  41
  42         *cnt = (comb >> IN_PROGRESS_BITS);
  43         *inpr = comb & MAX_IN_PROGRESS;
  44 }
  45
  46 /* A preserved old value of the events counter. */
  47 static unsigned int saved_count;
  48
  49 static DEFINE_SPINLOCK(events_lock);
  50
  51 static void pm_wakeup_timer_fn(unsigned long data);
  52
  53 static LIST_HEAD(wakeup_sources);
  54
  55 static DECLARE_WAIT_QUEUE_HEAD(wakeup_count_wait_queue);
  56
  57 /**
  58  * wakeup_source_prepare - Prepare a new wakeup source for initialization.
  59  * @ws: Wakeup source to prepare.
  60  * @name: Pointer to the name of the new wakeup source.
  61  *
  62  * Callers must ensure that the @name string won't be freed when @ws is still in
  63  * use.
  64  */
  65 void wakeup_source_prepare(struct wakeup_source *ws, const char *name)
  66 {
  67         if (ws) {
  68                 memset(ws, 0, sizeof(*ws));
  69                 ws->name = name;
  70         }
  71 }
  72 EXPORT_SYMBOL_GPL(wakeup_source_prepare);
  73
  74 /**
  75  * wakeup_source_create - Create a struct wakeup_source object.
  76  * @name: Name of the new wakeup source.
  77  */
  78 struct wakeup_source *wakeup_source_create(const char *name)
  79 {
  80         struct wakeup_source *ws;
  81
  82         ws = kmalloc(sizeof(*ws), GFP_KERNEL);
  83         if (!ws)
  84                 return NULL;
  85
  86         wakeup_source_prepare(ws, name ? kstrdup(name, GFP_KERNEL) : NULL);
  87         return ws;
  88 }
  89 EXPORT_SYMBOL_GPL(wakeup_source_create);
  90
  91 /**
  92  * wakeup_source_drop - Prepare a struct wakeup_source object for destruction.
  93  * @ws: Wakeup source to prepare for destruction.
  94  *
  95  * Callers must ensure that __pm_stay_awake() or __pm_wakeup_event() will never
  96  * be run in parallel with this function for the same wakeup source object.
  97  */
  98 void wakeup_source_drop(struct wakeup_source *ws)
  99 {
 100         if (!ws)
 101                 return;
 102
 103         del_timer_sync(&ws->timer);
 104         __pm_relax(ws);
 105 }
 106 EXPORT_SYMBOL_GPL(wakeup_source_drop);
 107
 108 /**
 109  * wakeup_source_destroy - Destroy a struct wakeup_source object.
 110  * @ws: Wakeup source to destroy.
 111  *
 112  * Use only for wakeup source objects created with wakeup_source_create().
 113  */
 114 void wakeup_source_destroy(struct wakeup_source *ws)
 115 {
 116         if (!ws)
 117                 return;
 118
 119         wakeup_source_drop(ws);
 120         kfree(ws->name);
 121         kfree(ws);
 122 }
 123 EXPORT_SYMBOL_GPL(wakeup_source_destroy);
 124
 125 /**
 126  * wakeup_source_add - Add given object to the list of wakeup sources.
 127  * @ws: Wakeup source object to add to the list.
 128  */
 129 void wakeup_source_add(struct wakeup_source *ws)
 130 {
 131         unsigned long flags;
 132
 133         if (WARN_ON(!ws))
 134                 return;
 135
 136         spin_lock_init(&ws->lock);
 137         setup_timer(&ws->timer, pm_wakeup_timer_fn, (unsigned long)ws);
 138         ws->active = false;
 139         ws->last_time = ktime_get();
 140
 141         spin_lock_irqsave(&events_lock, flags);
 142         list_add_rcu(&ws->entry, &wakeup_sources);
 143         spin_unlock_irqrestore(&events_lock, flags);
 144 }
 145 EXPORT_SYMBOL_GPL(wakeup_source_add);
 146
 147 /**
 148  * wakeup_source_remove - Remove given object from the wakeup sources list.
 149  * @ws: Wakeup source object to remove from the list.
 150  */
 151 void wakeup_source_remove(struct wakeup_source *ws)
 152 {
 153         unsigned long flags;
 154
 155         if (WARN_ON(!ws))
 156                 return;
 157
 158         spin_lock_irqsave(&events_lock, flags);
 159         list_del_rcu(&ws->entry);
 160         spin_unlock_irqrestore(&events_lock, flags);
 161         synchronize_rcu();
 162 }
 163 EXPORT_SYMBOL_GPL(wakeup_source_remove);
 164
 165 /**
 166  * wakeup_source_register - Create wakeup source and add it to the list.
 167  * @name: Name of the wakeup source to register.
 168  */
 169 struct wakeup_source *wakeup_source_register(const char *name)
 170 {
 171         struct wakeup_source *ws;
 172
 173         ws = wakeup_source_create(name);
 174         if (ws)
 175                 wakeup_source_add(ws);
 176
 177         return ws;
 178 }
 179 EXPORT_SYMBOL_GPL(wakeup_source_register);
 180
 181 /**
 182  * wakeup_source_unregister - Remove wakeup source from the list and remove it.
 183  * @ws: Wakeup source object to unregister.
 184  */
 185 void wakeup_source_unregister(struct wakeup_source *ws)
 186 {
 187         if (ws) {
 188                 wakeup_source_remove(ws);
 189                 wakeup_source_destroy(ws);
 190         }
 191 }
 192 EXPORT_SYMBOL_GPL(wakeup_source_unregister);
 193
 194 /**
 195  * device_wakeup_attach - Attach a wakeup source object to a device object.
 196  * @dev: Device to handle.
 197  * @ws: Wakeup source object to attach to @dev.
 198  *
 199  * This causes @dev to be treated as a wakeup device.
 200  */
 201 static int device_wakeup_attach(struct device *dev, struct wakeup_source *ws)
 202 {
 203         spin_lock_irq(&dev->power.lock);
 204         if (dev->power.wakeup) {
 205                 spin_unlock_irq(&dev->power.lock);
 206                 return -EEXIST;
 207         }
 208         dev->power.wakeup = ws;
 209         spin_unlock_irq(&dev->power.lock);
 210         return 0;
 211 }
 212
 213 /**
 214  * device_wakeup_enable - Enable given device to be a wakeup source.
 215  * @dev: Device to handle.
 216  *
 217  * Create a wakeup source object, register it and attach it to @dev.
 218  */
 219 int device_wakeup_enable(struct device *dev)
 220 {
 221         struct wakeup_source *ws;
 222         int ret;
 223
 224         if (!dev || !dev->power.can_wakeup)
 225                 return -EINVAL;
 226
 227         ws = wakeup_source_register(dev_name(dev));
 228         if (!ws)
 229                 return -ENOMEM;
 230
 231         ret = device_wakeup_attach(dev, ws);
 232         if (ret)
 233                 wakeup_source_unregister(ws);
 234
 235         return ret;
 236 }
 237 EXPORT_SYMBOL_GPL(device_wakeup_enable);
 238
 239 /**
 240  * device_wakeup_detach - Detach a device's wakeup source object from it.
 241  * @dev: Device to detach the wakeup source object from.
 242  *
 243  * After it returns, @dev will not be treated as a wakeup device any more.
 244  */
 245 static struct wakeup_source *device_wakeup_detach(struct device *dev)
 246 {
 247         struct wakeup_source *ws;
 248
 249         spin_lock_irq(&dev->power.lock);
 250         ws = dev->power.wakeup;
 251         dev->power.wakeup = NULL;
 252         spin_unlock_irq(&dev->power.lock);
 253         return ws;
 254 }
 255
 256 /**
 257  * device_wakeup_disable - Do not regard a device as a wakeup source any more.
 258  * @dev: Device to handle.
 259  *
 260  * Detach the @dev's wakeup source object from it, unregister this wakeup source
 261  * object and destroy it.
 262  */
 263 int device_wakeup_disable(struct device *dev)
 264 {
 265         struct wakeup_source *ws;
 266
 267         if (!dev || !dev->power.can_wakeup)
 268                 return -EINVAL;
 269
 270         ws = device_wakeup_detach(dev);
 271         if (ws)
 272                 wakeup_source_unregister(ws);
 273
 274         return 0;
 275 }
 276 EXPORT_SYMBOL_GPL(device_wakeup_disable);
 277
 278 /**
 279  * device_set_wakeup_capable - Set/reset device wakeup capability flag.
 280  * @dev: Device to handle.
 281  * @capable: Whether or not @dev is capable of waking up the system from sleep.
 282  *
 283  * If @capable is set, set the @dev's power.can_wakeup flag and add its
 284  * wakeup-related attributes to sysfs.  Otherwise, unset the @dev's
 285  * power.can_wakeup flag and remove its wakeup-related attributes from sysfs.
 286  *
 287  * This function may sleep and it can't be called from any context where
 288  * sleeping is not allowed.
 289  */
 290 void device_set_wakeup_capable(struct device *dev, bool capable)
 291 {
 292         if (!!dev->power.can_wakeup == !!capable)
 293                 return;
 294
 295         if (device_is_registered(dev) && !list_empty(&dev->power.entry)) {
 296                 if (capable) {
 297                         if (wakeup_sysfs_add(dev))
 298                                 return;
 299                 } else {
 300                         wakeup_sysfs_remove(dev);
 301                 }
 302         }
 303         dev->power.can_wakeup = capable;
 304 }
 305 EXPORT_SYMBOL_GPL(device_set_wakeup_capable);
 306
 307 /**
 308  * device_init_wakeup - Device wakeup initialization.
 309  * @dev: Device to handle.
 310  * @enable: Whether or not to enable @dev as a wakeup device.
 311  *
 312  * By default, most devices should leave wakeup disabled.  The exceptions are
 313  * devices that everyone expects to be wakeup sources: keyboards, power buttons,
 314  * possibly network interfaces, etc.  Also, devices that don't generate their
 315  * own wakeup requests but merely forward requests from one bus to another
 316  * (like PCI bridges) should have wakeup enabled by default.
 317  */
 318 int device_init_wakeup(struct device *dev, bool enable)
 319 {
 320         int ret = 0;
 321
 322         if (enable) {
 323                 device_set_wakeup_capable(dev, true);
 324                 ret = device_wakeup_enable(dev);
 325         } else {
 326                 device_set_wakeup_capable(dev, false);
 327         }
 328
 329         return ret;
 330 }
 331 EXPORT_SYMBOL_GPL(device_init_wakeup);
 332
 333 /**
 334  * device_set_wakeup_enable - Enable or disable a device to wake up the system.
 335  * @dev: Device to handle.
 336  */
 337 int device_set_wakeup_enable(struct device *dev, bool enable)
 338 {
 339         if (!dev || !dev->power.can_wakeup)
 340                 return -EINVAL;
 341
 342         return enable ? device_wakeup_enable(dev) : device_wakeup_disable(dev);
 343 }
 344 EXPORT_SYMBOL_GPL(device_set_wakeup_enable);
 345
 346 /**
 347  * wakeup_source_not_registered - validate the given wakeup source.
 348  * @ws: Wakeup source to be validated.
 349  */
 350 static bool wakeup_source_not_registered(struct wakeup_source *ws)
 351 {
 352         /*
 353          * Use timer struct to check if the given source is initialized
 354          * by wakeup_source_add.
 355          */
 356         return ws->timer.function != pm_wakeup_timer_fn ||
 357                    ws->timer.data != (unsigned long)ws;
 358 }
 359
 360 /*
 361  * The functions below use the observation that each wakeup event starts a
 362  * period in which the system should not be suspended.  The moment this period
 363  * will end depends on how the wakeup event is going to be processed after being
 364  * detected and all of the possible cases can be divided into two distinct
 365  * groups.
 366  *
 367  * First, a wakeup event may be detected by the same functional unit that will
 368  * carry out the entire processing of it and possibly will pass it to user space
 369  * for further processing.  In that case the functional unit that has detected
 370  * the event may later "close" the "no suspend" period associated with it
 371  * directly as soon as it has been dealt with.  The pair of pm_stay_awake() and
 372  * pm_relax(), balanced with each other, is supposed to be used in such
 373  * situations.
 374  *
 375  * Second, a wakeup event may be detected by one functional unit and processed
 376  * by another one.  In that case the unit that has detected it cannot really
 377  * "close" the "no suspend" period associated with it, unless it knows in
 378  * advance what's going to happen to the event during processing.  This
 379  * knowledge, however, may not be available to it, so it can simply specify time
 380  * to wait before the system can be suspended and pass it as the second
 381  * argument of pm_wakeup_event().
 382  *
 383  * It is valid to call pm_relax() after pm_wakeup_event(), in which case the
 384  * "no suspend" period will be ended either by the pm_relax(), or by the timer
 385  * function executed when the timer expires, whichever comes first.
 386  */
 387
 388 /**
 389  * wakup_source_activate - Mark given wakeup source as active.
 390  * @ws: Wakeup source to handle.
 391  *
 392  * Update the @ws' statistics and, if @ws has just been activated, notify the PM
 393  * core of the event by incrementing the counter of of wakeup events being
 394  * processed.
 395  */
 396 static void wakeup_source_activate(struct wakeup_source *ws)
 397 {
 398         unsigned int cec;
 399
 400         if (WARN(wakeup_source_not_registered(ws),
 401                         "unregistered wakeup source\n"))
 402                 return;
 403
 404         /*
 405          * active wakeup source should bring the system
 406          * out of PM_SUSPEND_FREEZE state
 407          */
 408         freeze_wake();
 409
 410         ws->active = true;
 411         ws->active_count++;
 412         ws->last_time = ktime_get();
 413         if (ws->autosleep_enabled)
 414                 ws->start_prevent_time = ws->last_time;
 415
 416         /* Increment the counter of events in progress. */
 417         cec = atomic_inc_return(&combined_event_count);
 418
 419         trace_wakeup_source_activate(ws->name, cec);
 420 }
 421
 422 /**
 423  * wakeup_source_report_event - Report wakeup event using the given source.
 424  * @ws: Wakeup source to report the event for.
 425  */
 426 static void wakeup_source_report_event(struct wakeup_source *ws)
 427 {
 428         ws->event_count++;
 429         /* This is racy, but the counter is approximate anyway. */
 430         if (events_check_enabled)
 431                 ws->wakeup_count++;
 432
 433         if (!ws->active)
 434                 wakeup_source_activate(ws);
 435 }
 436
 437 /**
 438  * __pm_stay_awake - Notify the PM core of a wakeup event.
 439  * @ws: Wakeup source object associated with the source of the event.
 440  *
 441  * It is safe to call this function from interrupt context.
 442  */
 443 void __pm_stay_awake(struct wakeup_source *ws)
 444 {
 445         unsigned long flags;
 446
 447         if (!ws)
 448                 return;
 449
 450         spin_lock_irqsave(&ws->lock, flags);
 451
 452         wakeup_source_report_event(ws);
 453         del_timer(&ws->timer);
 454         ws->timer_expires = 0;
 455
 456         spin_unlock_irqrestore(&ws->lock, flags);
 457 }
 458 EXPORT_SYMBOL_GPL(__pm_stay_awake);
 459
 460 /**
 461  * pm_stay_awake - Notify the PM core that a wakeup event is being processed.
 462  * @dev: Device the wakeup event is related to.
 463  *
 464  * Notify the PM core of a wakeup event (signaled by @dev) by calling
 465  * __pm_stay_awake for the @dev's wakeup source object.
 466  *
 467  * Call this function after detecting of a wakeup event if pm_relax() is going
 468  * to be called directly after processing the event (and possibly passing it to
 469  * user space for further processing).
 470  */
 471 void pm_stay_awake(struct device *dev)
 472 {
 473         unsigned long flags;
 474
 475         if (!dev)
 476                 return;
 477
 478         spin_lock_irqsave(&dev->power.lock, flags);
 479         __pm_stay_awake(dev->power.wakeup);
 480         spin_unlock_irqrestore(&dev->power.lock, flags);
 481 }
 482 EXPORT_SYMBOL_GPL(pm_stay_awake);
 483
 484 #ifdef CONFIG_PM_AUTOSLEEP
 485 static void update_prevent_sleep_time(struct wakeup_source *ws, ktime_t now)
 486 {
 487         ktime_t delta = ktime_sub(now, ws->start_prevent_time);
 488         ws->prevent_sleep_time = ktime_add(ws->prevent_sleep_time, delta);
 489 }
 490 #else
 491 static inline void update_prevent_sleep_time(struct wakeup_source *ws,
 492                                              ktime_t now) {}
 493 #endif
 494
 495 /**
 496  * wakup_source_deactivate - Mark given wakeup source as inactive.
 497  * @ws: Wakeup source to handle.
 498  *
 499  * Update the @ws' statistics and notify the PM core that the wakeup source has
 500  * become inactive by decrementing the counter of wakeup events being processed
 501  * and incrementing the counter of registered wakeup events.
 502  */
 503 static void wakeup_source_deactivate(struct wakeup_source *ws)
 504 {
 505         unsigned int cnt, inpr, cec;
 506         ktime_t duration;
 507         ktime_t now;
 508
 509         ws->relax_count++;
 510         /*
 511          * __pm_relax() may be called directly or from a timer function.
 512          * If it is called directly right after the timer function has been
 513          * started, but before the timer function calls __pm_relax(), it is
 514          * possible that __pm_stay_awake() will be called in the meantime and
 515          * will set ws->active.  Then, ws->active may be cleared immediately
 516          * by the __pm_relax() called from the timer function, but in such a
 517          * case ws->relax_count will be different from ws->active_count.
 518          */
 519         if (ws->relax_count != ws->active_count) {
 520                 ws->relax_count--;
 521                 return;
 522         }
 523
 524         ws->active = false;
 525
 526         now = ktime_get();
 527         duration = ktime_sub(now, ws->last_time);
 528         ws->total_time = ktime_add(ws->total_time, duration);
 529         if (ktime_to_ns(duration) > ktime_to_ns(ws->max_time))
 530                 ws->max_time = duration;
 531
 532         ws->last_time = now;
 533         del_timer(&ws->timer);
 534         ws->timer_expires = 0;
 535
 536         if (ws->autosleep_enabled)
 537                 update_prevent_sleep_time(ws, now);
 538
 539         /*
 540          * Increment the counter of registered wakeup events and decrement the
 541          * couter of wakeup events in progress simultaneously.
 542          */
 543         cec = atomic_add_return(MAX_IN_PROGRESS, &combined_event_count);
 544         trace_wakeup_source_deactivate(ws->name, cec);
 545
 546         split_counters(&cnt, &inpr);
 547         if (!inpr && waitqueue_active(&wakeup_count_wait_queue))
 548                 wake_up(&wakeup_count_wait_queue);
 549 }
 550
 551 /**
 552  * __pm_relax - Notify the PM core that processing of a wakeup event has ended.
 553  * @ws: Wakeup source object associated with the source of the event.
 554  *
 555  * Call this function for wakeup events whose processing started with calling
 556  * __pm_stay_awake().
 557  *
 558  * It is safe to call it from interrupt context.
 559  */
 560 void __pm_relax(struct wakeup_source *ws)
 561 {
 562         unsigned long flags;
 563
 564         if (!ws)
 565                 return;
 566
 567         spin_lock_irqsave(&ws->lock, flags);
 568         if (ws->active)
 569                 wakeup_source_deactivate(ws);
 570         spin_unlock_irqrestore(&ws->lock, flags);
 571 }
 572 EXPORT_SYMBOL_GPL(__pm_relax);
 573
 574 /**
 575  * pm_relax - Notify the PM core that processing of a wakeup event has ended.
 576  * @dev: Device that signaled the event.
 577  *
 578  * Execute __pm_relax() for the @dev's wakeup source object.
 579  */
 580 void pm_relax(struct device *dev)
 581 {
 582         unsigned long flags;
 583
 584         if (!dev)
 585                 return;
 586
 587         spin_lock_irqsave(&dev->power.lock, flags);
 588         __pm_relax(dev->power.wakeup);
 589         spin_unlock_irqrestore(&dev->power.lock, flags);
 590 }
 591 EXPORT_SYMBOL_GPL(pm_relax);
 592
 593 /**
 594  * pm_wakeup_timer_fn - Delayed finalization of a wakeup event.
 595  * @data: Address of the wakeup source object associated with the event source.
 596  *
 597  * Call wakeup_source_deactivate() for the wakeup source whose address is stored
 598  * in @data if it is currently active and its timer has not been canceled and
 599  * the expiration time of the timer is not in future.
 600  */
 601 static void pm_wakeup_timer_fn(unsigned long data)
 602 {
 603         struct wakeup_source *ws = (struct wakeup_source *)data;
 604         unsigned long flags;
 605
 606         spin_lock_irqsave(&ws->lock, flags);
 607
 608         if (ws->active && ws->timer_expires
 609             && time_after_eq(jiffies, ws->timer_expires)) {
 610                 wakeup_source_deactivate(ws);
 611                 ws->expire_count++;
 612         }
 613
 614         spin_unlock_irqrestore(&ws->lock, flags);
 615 }
 616
 617 /**
 618  * __pm_wakeup_event - Notify the PM core of a wakeup event.
 619  * @ws: Wakeup source object associated with the event source.
 620  * @msec: Anticipated event processing time (in milliseconds).
 621  *
 622  * Notify the PM core of a wakeup event whose source is @ws that will take
 623  * approximately @msec milliseconds to be processed by the kernel.  If @ws is
 624  * not active, activate it.  If @msec is nonzero, set up the @ws' timer to
 625  * execute pm_wakeup_timer_fn() in future.
 626  *
 627  * It is safe to call this function from interrupt context.
 628  */
 629 void __pm_wakeup_event(struct wakeup_source *ws, unsigned int msec)
 630 {
 631         unsigned long flags;
 632         unsigned long expires;
 633
 634         if (!ws)
 635                 return;
 636
 637         spin_lock_irqsave(&ws->lock, flags);
 638
 639         wakeup_source_report_event(ws);
 640
 641         if (!msec) {
 642                 wakeup_source_deactivate(ws);
 643                 goto unlock;
 644         }
 645
 646         expires = jiffies + msecs_to_jiffies(msec);
 647         if (!expires)
 648                 expires = 1;
 649
 650         if (!ws->timer_expires || time_after(expires, ws->timer_expires)) {
 651                 mod_timer(&ws->timer, expires);
 652                 ws->timer_expires = expires;
 653         }
 654
 655  unlock:
 656         spin_unlock_irqrestore(&ws->lock, flags);
 657 }
 658 EXPORT_SYMBOL_GPL(__pm_wakeup_event);
 659
 660
 661 /**
 662  * pm_wakeup_event - Notify the PM core of a wakeup event.
 663  * @dev: Device the wakeup event is related to.
 664  * @msec: Anticipated event processing time (in milliseconds).
 665  *
 666  * Call __pm_wakeup_event() for the @dev's wakeup source object.
 667  */
 668 void pm_wakeup_event(struct device *dev, unsigned int msec)
 669 {
 670         unsigned long flags;
 671
 672         if (!dev)
 673                 return;
 674
 675         spin_lock_irqsave(&dev->power.lock, flags);
 676         __pm_wakeup_event(dev->power.wakeup, msec);
 677         spin_unlock_irqrestore(&dev->power.lock, flags);
 678 }
 679 EXPORT_SYMBOL_GPL(pm_wakeup_event);
 680
 681 void pm_get_active_wakeup_sources(char *pending_wakeup_source, size_t max)
 682 {
 683         struct wakeup_source *ws, *last_active_ws = NULL;
 684         int len = 0;
 685         bool active = false;
 686
 687         rcu_read_lock();
 688         list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
 689                 if (ws->active) {
 690                         if (!active)
 691                                 len += scnprintf(pending_wakeup_source, max,
 692                                                 "Pending Wakeup Sources: ");
 693                         len += scnprintf(pending_wakeup_source + len, max - len,
 694                                 "%s ", ws->name);
 695                         active = true;
 696                 } else if (!active &&
 697                            (!last_active_ws ||
 698                             ktime_to_ns(ws->last_time) >
 699                             ktime_to_ns(last_active_ws->last_time))) {
 700                         last_active_ws = ws;
 701                 }
 702         }
 703         if (!active && last_active_ws) {
 704                 scnprintf(pending_wakeup_source, max,
 705                                 "Last active Wakeup Source: %s",
 706                                 last_active_ws->name);
 707         }
 708         rcu_read_unlock();
 709 }
 710 EXPORT_SYMBOL_GPL(pm_get_active_wakeup_sources);
 711
 712 static void print_active_wakeup_sources(void)
 713 {
 714         struct wakeup_source *ws;
 715         int active = 0;
 716         struct wakeup_source *last_activity_ws = NULL;
 717
 718         rcu_read_lock();
 719         list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
 720                 if (ws->active) {
 721                         pr_info("active wakeup source: %s\n", ws->name);
 722                         active = 1;
 723                 } else if (!active &&
 724                            (!last_activity_ws ||
 725                             ktime_to_ns(ws->last_time) >
 726                             ktime_to_ns(last_activity_ws->last_time))) {
 727                         last_activity_ws = ws;
 728                 }
 729         }
 730
 731         if (!active && last_activity_ws)
 732                 pr_info("last active wakeup source: %s\n",
 733                         last_activity_ws->name);
 734         rcu_read_unlock();
 735 }
 736
 737 /**
 738  * pm_wakeup_pending - Check if power transition in progress should be aborted.
 739  *
 740  * Compare the current number of registered wakeup events with its preserved
 741  * value from the past and return true if new wakeup events have been registered
 742  * since the old value was stored.  Also return true if the current number of
 743  * wakeup events being processed is different from zero.
 744  */
 745 bool pm_wakeup_pending(void)
 746 {
 747         unsigned long flags;
 748         bool ret = false;
 749
 750         spin_lock_irqsave(&events_lock, flags);
 751         if (events_check_enabled) {
 752                 unsigned int cnt, inpr;
 753
 754                 split_counters(&cnt, &inpr);
 755                 ret = (cnt != saved_count || inpr > 0);
 756                 events_check_enabled = !ret;
 757         }
 758         spin_unlock_irqrestore(&events_lock, flags);
 759
 760         if (ret)
 761                 print_active_wakeup_sources();
 762
 763         return ret;
 764 }
 765
 766 /**
 767  * pm_get_wakeup_count - Read the number of registered wakeup events.
 768  * @count: Address to store the value at.
 769  * @block: Whether or not to block.
 770  *
 771  * Store the number of registered wakeup events at the address in @count.  If
 772  * @block is set, block until the current number of wakeup events being
 773  * processed is zero.
 774  *
 775  * Return 'false' if the current number of wakeup events being processed is
 776  * nonzero.  Otherwise return 'true'.
 777  */
 778 bool pm_get_wakeup_count(unsigned int *count, bool block)
 779 {
 780         unsigned int cnt, inpr;
 781
 782         if (block) {
 783                 DEFINE_WAIT(wait);
 784
 785                 for (;;) {
 786                         prepare_to_wait(&wakeup_count_wait_queue, &wait,
 787                                         TASK_INTERRUPTIBLE);
 788                         split_counters(&cnt, &inpr);
 789                         if (inpr == 0 || signal_pending(current))
 790                                 break;
 791
 792                         schedule();
 793                 }
 794                 finish_wait(&wakeup_count_wait_queue, &wait);
 795         }
 796
 797         split_counters(&cnt, &inpr);
 798         *count = cnt;
 799         return !inpr;
 800 }
 801
 802 /**
 803  * pm_save_wakeup_count - Save the current number of registered wakeup events.
 804  * @count: Value to compare with the current number of registered wakeup events.
 805  *
 806  * If @count is equal to the current number of registered wakeup events and the
 807  * current number of wakeup events being processed is zero, store @count as the
 808  * old number of registered wakeup events for pm_check_wakeup_events(), enable
 809  * wakeup events detection and return 'true'.  Otherwise disable wakeup events
 810  * detection and return 'false'.
 811  */
 812 bool pm_save_wakeup_count(unsigned int count)
 813 {
 814         unsigned int cnt, inpr;
 815         unsigned long flags;
 816
 817         events_check_enabled = false;
 818         spin_lock_irqsave(&events_lock, flags);
 819         split_counters(&cnt, &inpr);
 820         if (cnt == count && inpr == 0) {
 821                 saved_count = count;
 822                 events_check_enabled = true;
 823         }
 824         spin_unlock_irqrestore(&events_lock, flags);
 825         return events_check_enabled;
 826 }
 827
 828 #ifdef CONFIG_PM_AUTOSLEEP
 829 /**
 830  * pm_wakep_autosleep_enabled - Modify autosleep_enabled for all wakeup sources.
 831  * @enabled: Whether to set or to clear the autosleep_enabled flags.
 832  */
 833 void pm_wakep_autosleep_enabled(bool set)
 834 {
 835         struct wakeup_source *ws;
 836         ktime_t now = ktime_get();
 837
 838         rcu_read_lock();
 839         list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
 840                 spin_lock_irq(&ws->lock);
 841                 if (ws->autosleep_enabled != set) {
 842                         ws->autosleep_enabled = set;
 843                         if (ws->active) {
 844                                 if (set)
 845                                         ws->start_prevent_time = now;
 846                                 else
 847                                         update_prevent_sleep_time(ws, now);
 848                         }
 849                 }
 850                 spin_unlock_irq(&ws->lock);
 851         }
 852         rcu_read_unlock();
 853 }
 854 #endif /* CONFIG_PM_AUTOSLEEP */
 855
 856 static struct dentry *wakeup_sources_stats_dentry;
 857
 858 /**
 859  * print_wakeup_source_stats - Print wakeup source statistics information.
 860  * @m: seq_file to print the statistics into.
 861  * @ws: Wakeup source object to print the statistics for.
 862  */
 863 static int print_wakeup_source_stats(struct seq_file *m,
 864                                      struct wakeup_source *ws)
 865 {
 866         unsigned long flags;
 867         ktime_t total_time;
 868         ktime_t max_time;
 869         unsigned long active_count;
 870         ktime_t active_time;
 871         ktime_t prevent_sleep_time;
 872         int ret;
 873
 874         spin_lock_irqsave(&ws->lock, flags);
 875
 876         total_time = ws->total_time;
 877         max_time = ws->max_time;
 878         prevent_sleep_time = ws->prevent_sleep_time;
 879         active_count = ws->active_count;
 880         if (ws->active) {
 881                 ktime_t now = ktime_get();
 882
 883                 active_time = ktime_sub(now, ws->last_time);
 884                 total_time = ktime_add(total_time, active_time);
 885                 if (active_time.tv64 > max_time.tv64)
 886                         max_time = active_time;
 887
 888                 if (ws->autosleep_enabled)
 889                         prevent_sleep_time = ktime_add(prevent_sleep_time,
 890                                 ktime_sub(now, ws->start_prevent_time));
 891         } else {
 892                 active_time = ktime_set(0, 0);
 893         }
 894
 895         ret = seq_printf(m, "%-12s\t%lu\t\t%lu\t\t%lu\t\t%lu\t\t"
 896                         "%lld\t\t%lld\t\t%lld\t\t%lld\t\t%lld\n",
 897                         ws->name, active_count, ws->event_count,
 898                         ws->wakeup_count, ws->expire_count,
 899                         ktime_to_ms(active_time), ktime_to_ms(total_time),
 900                         ktime_to_ms(max_time), ktime_to_ms(ws->last_time),
 901                         ktime_to_ms(prevent_sleep_time));
 902
 903         spin_unlock_irqrestore(&ws->lock, flags);
 904
 905         return ret;
 906 }
 907
 908 /**
 909  * wakeup_sources_stats_show - Print wakeup sources statistics information.
 910  * @m: seq_file to print the statistics into.
 911  */
 912 static int wakeup_sources_stats_show(struct seq_file *m, void *unused)
 913 {
 914         struct wakeup_source *ws;
 915
 916         seq_puts(m, "name\t\tactive_count\tevent_count\twakeup_count\t"
 917                 "expire_count\tactive_since\ttotal_time\tmax_time\t"
 918                 "last_change\tprevent_suspend_time\n");
 919
 920         rcu_read_lock();
 921         list_for_each_entry_rcu(ws, &wakeup_sources, entry)
 922                 print_wakeup_source_stats(m, ws);
 923         rcu_read_unlock();
 924
 925         return 0;
 926 }
 927
 928 static int wakeup_sources_stats_open(struct inode *inode, struct file *file)
 929 {
 930         return single_open(file, wakeup_sources_stats_show, NULL);
 931 }
 932
 933 static const struct file_operations wakeup_sources_stats_fops = {
 934         .owner = THIS_MODULE,
 935         .open = wakeup_sources_stats_open,
 936         .read = seq_read,
 937         .llseek = seq_lseek,
 938         .release = single_release,
 939 };
 940
 941 static int __init wakeup_sources_debugfs_init(void)
 942 {
 943         wakeup_sources_stats_dentry = debugfs_create_file("wakeup_sources",
 944                         S_IRUGO, NULL, NULL, &wakeup_sources_stats_fops);
 945         return 0;
 946 }
 947
 948 postcore_initcall(wakeup_sources_debugfs_init);