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         ws->active = true;
 386         ws->active_count++;
 387         ws->last_time = ktime_get();
 388         if (ws->autosleep_enabled)
 389                 ws->start_prevent_time = ws->last_time;
 390
 391         /* Increment the counter of events in progress. */
 392         cec = atomic_inc_return(&combined_event_count);
 393
 394         trace_wakeup_source_activate(ws->name, cec);
 395 }
 396
 397 /**
 398  * wakeup_source_report_event - Report wakeup event using the given source.
 399  * @ws: Wakeup source to report the event for.
 400  */
 401 static void wakeup_source_report_event(struct wakeup_source *ws)
 402 {
 403         ws->event_count++;
 404         /* This is racy, but the counter is approximate anyway. */
 405         if (events_check_enabled)
 406                 ws->wakeup_count++;
 407
 408         if (!ws->active)
 409                 wakeup_source_activate(ws);
 410 }
 411
 412 /**
 413  * __pm_stay_awake - Notify the PM core of a wakeup event.
 414  * @ws: Wakeup source object associated with the source of the event.
 415  *
 416  * It is safe to call this function from interrupt context.
 417  */
 418 void __pm_stay_awake(struct wakeup_source *ws)
 419 {
 420         unsigned long flags;
 421
 422         if (!ws)
 423                 return;
 424
 425         spin_lock_irqsave(&ws->lock, flags);
 426
 427         wakeup_source_report_event(ws);
 428         del_timer(&ws->timer);
 429         ws->timer_expires = 0;
 430
 431         spin_unlock_irqrestore(&ws->lock, flags);
 432 }
 433 EXPORT_SYMBOL_GPL(__pm_stay_awake);
 434
 435 /**
 436  * pm_stay_awake - Notify the PM core that a wakeup event is being processed.
 437  * @dev: Device the wakeup event is related to.
 438  *
 439  * Notify the PM core of a wakeup event (signaled by @dev) by calling
 440  * __pm_stay_awake for the @dev's wakeup source object.
 441  *
 442  * Call this function after detecting of a wakeup event if pm_relax() is going
 443  * to be called directly after processing the event (and possibly passing it to
 444  * user space for further processing).
 445  */
 446 void pm_stay_awake(struct device *dev)
 447 {
 448         unsigned long flags;
 449
 450         if (!dev)
 451                 return;
 452
 453         spin_lock_irqsave(&dev->power.lock, flags);
 454         __pm_stay_awake(dev->power.wakeup);
 455         spin_unlock_irqrestore(&dev->power.lock, flags);
 456 }
 457 EXPORT_SYMBOL_GPL(pm_stay_awake);
 458
 459 #ifdef CONFIG_PM_AUTOSLEEP
 460 static void update_prevent_sleep_time(struct wakeup_source *ws, ktime_t now)
 461 {
 462         ktime_t delta = ktime_sub(now, ws->start_prevent_time);
 463         ws->prevent_sleep_time = ktime_add(ws->prevent_sleep_time, delta);
 464 }
 465 #else
 466 static inline void update_prevent_sleep_time(struct wakeup_source *ws,
 467                                              ktime_t now) {}
 468 #endif
 469
 470 /**
 471  * wakup_source_deactivate - Mark given wakeup source as inactive.
 472  * @ws: Wakeup source to handle.
 473  *
 474  * Update the @ws' statistics and notify the PM core that the wakeup source has
 475  * become inactive by decrementing the counter of wakeup events being processed
 476  * and incrementing the counter of registered wakeup events.
 477  */
 478 static void wakeup_source_deactivate(struct wakeup_source *ws)
 479 {
 480         unsigned int cnt, inpr, cec;
 481         ktime_t duration;
 482         ktime_t now;
 483
 484         ws->relax_count++;
 485         /*
 486          * __pm_relax() may be called directly or from a timer function.
 487          * If it is called directly right after the timer function has been
 488          * started, but before the timer function calls __pm_relax(), it is
 489          * possible that __pm_stay_awake() will be called in the meantime and
 490          * will set ws->active.  Then, ws->active may be cleared immediately
 491          * by the __pm_relax() called from the timer function, but in such a
 492          * case ws->relax_count will be different from ws->active_count.
 493          */
 494         if (ws->relax_count != ws->active_count) {
 495                 ws->relax_count--;
 496                 return;
 497         }
 498
 499         ws->active = false;
 500
 501         now = ktime_get();
 502         duration = ktime_sub(now, ws->last_time);
 503         ws->total_time = ktime_add(ws->total_time, duration);
 504         if (ktime_to_ns(duration) > ktime_to_ns(ws->max_time))
 505                 ws->max_time = duration;
 506
 507         ws->last_time = now;
 508         del_timer(&ws->timer);
 509         ws->timer_expires = 0;
 510
 511         if (ws->autosleep_enabled)
 512                 update_prevent_sleep_time(ws, now);
 513
 514         /*
 515          * Increment the counter of registered wakeup events and decrement the
 516          * couter of wakeup events in progress simultaneously.
 517          */
 518         cec = atomic_add_return(MAX_IN_PROGRESS, &combined_event_count);
 519         trace_wakeup_source_deactivate(ws->name, cec);
 520
 521         split_counters(&cnt, &inpr);
 522         if (!inpr && waitqueue_active(&wakeup_count_wait_queue))
 523                 wake_up(&wakeup_count_wait_queue);
 524 }
 525
 526 /**
 527  * __pm_relax - Notify the PM core that processing of a wakeup event has ended.
 528  * @ws: Wakeup source object associated with the source of the event.
 529  *
 530  * Call this function for wakeup events whose processing started with calling
 531  * __pm_stay_awake().
 532  *
 533  * It is safe to call it from interrupt context.
 534  */
 535 void __pm_relax(struct wakeup_source *ws)
 536 {
 537         unsigned long flags;
 538
 539         if (!ws)
 540                 return;
 541
 542         spin_lock_irqsave(&ws->lock, flags);
 543         if (ws->active)
 544                 wakeup_source_deactivate(ws);
 545         spin_unlock_irqrestore(&ws->lock, flags);
 546 }
 547 EXPORT_SYMBOL_GPL(__pm_relax);
 548
 549 /**
 550  * pm_relax - Notify the PM core that processing of a wakeup event has ended.
 551  * @dev: Device that signaled the event.
 552  *
 553  * Execute __pm_relax() for the @dev's wakeup source object.
 554  */
 555 void pm_relax(struct device *dev)
 556 {
 557         unsigned long flags;
 558
 559         if (!dev)
 560                 return;
 561
 562         spin_lock_irqsave(&dev->power.lock, flags);
 563         __pm_relax(dev->power.wakeup);
 564         spin_unlock_irqrestore(&dev->power.lock, flags);
 565 }
 566 EXPORT_SYMBOL_GPL(pm_relax);
 567
 568 /**
 569  * pm_wakeup_timer_fn - Delayed finalization of a wakeup event.
 570  * @data: Address of the wakeup source object associated with the event source.
 571  *
 572  * Call wakeup_source_deactivate() for the wakeup source whose address is stored
 573  * in @data if it is currently active and its timer has not been canceled and
 574  * the expiration time of the timer is not in future.
 575  */
 576 static void pm_wakeup_timer_fn(unsigned long data)
 577 {
 578         struct wakeup_source *ws = (struct wakeup_source *)data;
 579         unsigned long flags;
 580
 581         spin_lock_irqsave(&ws->lock, flags);
 582
 583         if (ws->active && ws->timer_expires
 584             && time_after_eq(jiffies, ws->timer_expires)) {
 585                 wakeup_source_deactivate(ws);
 586                 ws->expire_count++;
 587         }
 588
 589         spin_unlock_irqrestore(&ws->lock, flags);
 590 }
 591
 592 /**
 593  * __pm_wakeup_event - Notify the PM core of a wakeup event.
 594  * @ws: Wakeup source object associated with the event source.
 595  * @msec: Anticipated event processing time (in milliseconds).
 596  *
 597  * Notify the PM core of a wakeup event whose source is @ws that will take
 598  * approximately @msec milliseconds to be processed by the kernel.  If @ws is
 599  * not active, activate it.  If @msec is nonzero, set up the @ws' timer to
 600  * execute pm_wakeup_timer_fn() in future.
 601  *
 602  * It is safe to call this function from interrupt context.
 603  */
 604 void __pm_wakeup_event(struct wakeup_source *ws, unsigned int msec)
 605 {
 606         unsigned long flags;
 607         unsigned long expires;
 608
 609         if (!ws)
 610                 return;
 611
 612         spin_lock_irqsave(&ws->lock, flags);
 613
 614         wakeup_source_report_event(ws);
 615
 616         if (!msec) {
 617                 wakeup_source_deactivate(ws);
 618                 goto unlock;
 619         }
 620
 621         expires = jiffies + msecs_to_jiffies(msec);
 622         if (!expires)
 623                 expires = 1;
 624
 625         if (!ws->timer_expires || time_after(expires, ws->timer_expires)) {
 626                 mod_timer(&ws->timer, expires);
 627                 ws->timer_expires = expires;
 628         }
 629
 630  unlock:
 631         spin_unlock_irqrestore(&ws->lock, flags);
 632 }
 633 EXPORT_SYMBOL_GPL(__pm_wakeup_event);
 634
 635
 636 /**
 637  * pm_wakeup_event - Notify the PM core of a wakeup event.
 638  * @dev: Device the wakeup event is related to.
 639  * @msec: Anticipated event processing time (in milliseconds).
 640  *
 641  * Call __pm_wakeup_event() for the @dev's wakeup source object.
 642  */
 643 void pm_wakeup_event(struct device *dev, unsigned int msec)
 644 {
 645         unsigned long flags;
 646
 647         if (!dev)
 648                 return;
 649
 650         spin_lock_irqsave(&dev->power.lock, flags);
 651         __pm_wakeup_event(dev->power.wakeup, msec);
 652         spin_unlock_irqrestore(&dev->power.lock, flags);
 653 }
 654 EXPORT_SYMBOL_GPL(pm_wakeup_event);
 655
 656 static void print_active_wakeup_sources(void)
 657 {
 658         struct wakeup_source *ws;
 659         int active = 0;
 660         struct wakeup_source *last_activity_ws = NULL;
 661
 662         rcu_read_lock();
 663         list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
 664                 if (ws->active) {
 665                         pr_info("active wakeup source: %s\n", ws->name);
 666                         active = 1;
 667                 } else if (!active &&
 668                            (!last_activity_ws ||
 669                             ktime_to_ns(ws->last_time) >
 670                             ktime_to_ns(last_activity_ws->last_time))) {
 671                         last_activity_ws = ws;
 672                 }
 673         }
 674
 675         if (!active && last_activity_ws)
 676                 pr_info("last active wakeup source: %s\n",
 677                         last_activity_ws->name);
 678         rcu_read_unlock();
 679 }
 680
 681 /**
 682  * pm_wakeup_pending - Check if power transition in progress should be aborted.
 683  *
 684  * Compare the current number of registered wakeup events with its preserved
 685  * value from the past and return true if new wakeup events have been registered
 686  * since the old value was stored.  Also return true if the current number of
 687  * wakeup events being processed is different from zero.
 688  */
 689 bool pm_wakeup_pending(void)
 690 {
 691         unsigned long flags;
 692         bool ret = false;
 693
 694         spin_lock_irqsave(&events_lock, flags);
 695         if (events_check_enabled) {
 696                 unsigned int cnt, inpr;
 697
 698                 split_counters(&cnt, &inpr);
 699                 ret = (cnt != saved_count || inpr > 0);
 700                 events_check_enabled = !ret;
 701         }
 702         spin_unlock_irqrestore(&events_lock, flags);
 703
 704         if (ret)
 705                 print_active_wakeup_sources();
 706
 707         return ret;
 708 }
 709
 710 /**
 711  * pm_get_wakeup_count - Read the number of registered wakeup events.
 712  * @count: Address to store the value at.
 713  * @block: Whether or not to block.
 714  *
 715  * Store the number of registered wakeup events at the address in @count.  If
 716  * @block is set, block until the current number of wakeup events being
 717  * processed is zero.
 718  *
 719  * Return 'false' if the current number of wakeup events being processed is
 720  * nonzero.  Otherwise return 'true'.
 721  */
 722 bool pm_get_wakeup_count(unsigned int *count, bool block)
 723 {
 724         unsigned int cnt, inpr;
 725
 726         if (block) {
 727                 DEFINE_WAIT(wait);
 728
 729                 for (;;) {
 730                         prepare_to_wait(&wakeup_count_wait_queue, &wait,
 731                                         TASK_INTERRUPTIBLE);
 732                         split_counters(&cnt, &inpr);
 733                         if (inpr == 0 || signal_pending(current))
 734                                 break;
 735
 736                         schedule();
 737                 }
 738                 finish_wait(&wakeup_count_wait_queue, &wait);
 739         }
 740
 741         split_counters(&cnt, &inpr);
 742         *count = cnt;
 743         return !inpr;
 744 }
 745
 746 /**
 747  * pm_save_wakeup_count - Save the current number of registered wakeup events.
 748  * @count: Value to compare with the current number of registered wakeup events.
 749  *
 750  * If @count is equal to the current number of registered wakeup events and the
 751  * current number of wakeup events being processed is zero, store @count as the
 752  * old number of registered wakeup events for pm_check_wakeup_events(), enable
 753  * wakeup events detection and return 'true'.  Otherwise disable wakeup events
 754  * detection and return 'false'.
 755  */
 756 bool pm_save_wakeup_count(unsigned int count)
 757 {
 758         unsigned int cnt, inpr;
 759         unsigned long flags;
 760
 761         events_check_enabled = false;
 762         spin_lock_irqsave(&events_lock, flags);
 763         split_counters(&cnt, &inpr);
 764         if (cnt == count && inpr == 0) {
 765                 saved_count = count;
 766                 events_check_enabled = true;
 767         }
 768         spin_unlock_irqrestore(&events_lock, flags);
 769         return events_check_enabled;
 770 }
 771
 772 #ifdef CONFIG_PM_AUTOSLEEP
 773 /**
 774  * pm_wakep_autosleep_enabled - Modify autosleep_enabled for all wakeup sources.
 775  * @enabled: Whether to set or to clear the autosleep_enabled flags.
 776  */
 777 void pm_wakep_autosleep_enabled(bool set)
 778 {
 779         struct wakeup_source *ws;
 780         ktime_t now = ktime_get();
 781
 782         rcu_read_lock();
 783         list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
 784                 spin_lock_irq(&ws->lock);
 785                 if (ws->autosleep_enabled != set) {
 786                         ws->autosleep_enabled = set;
 787                         if (ws->active) {
 788                                 if (set)
 789                                         ws->start_prevent_time = now;
 790                                 else
 791                                         update_prevent_sleep_time(ws, now);
 792                         }
 793                 }
 794                 spin_unlock_irq(&ws->lock);
 795         }
 796         rcu_read_unlock();
 797 }
 798 #endif /* CONFIG_PM_AUTOSLEEP */
 799
 800 static struct dentry *wakeup_sources_stats_dentry;
 801
 802 /**
 803  * print_wakeup_source_stats - Print wakeup source statistics information.
 804  * @m: seq_file to print the statistics into.
 805  * @ws: Wakeup source object to print the statistics for.
 806  */
 807 static int print_wakeup_source_stats(struct seq_file *m,
 808                                      struct wakeup_source *ws)
 809 {
 810         unsigned long flags;
 811         ktime_t total_time;
 812         ktime_t max_time;
 813         unsigned long active_count;
 814         ktime_t active_time;
 815         ktime_t prevent_sleep_time;
 816         int ret;
 817
 818         spin_lock_irqsave(&ws->lock, flags);
 819
 820         total_time = ws->total_time;
 821         max_time = ws->max_time;
 822         prevent_sleep_time = ws->prevent_sleep_time;
 823         active_count = ws->active_count;
 824         if (ws->active) {
 825                 ktime_t now = ktime_get();
 826
 827                 active_time = ktime_sub(now, ws->last_time);
 828                 total_time = ktime_add(total_time, active_time);
 829                 if (active_time.tv64 > max_time.tv64)
 830                         max_time = active_time;
 831
 832                 if (ws->autosleep_enabled)
 833                         prevent_sleep_time = ktime_add(prevent_sleep_time,
 834                                 ktime_sub(now, ws->start_prevent_time));
 835         } else {
 836                 active_time = ktime_set(0, 0);
 837         }
 838
 839         ret = seq_printf(m, "%-12s\t%lu\t\t%lu\t\t%lu\t\t%lu\t\t"
 840                         "%lld\t\t%lld\t\t%lld\t\t%lld\t\t%lld\n",
 841                         ws->name, active_count, ws->event_count,
 842                         ws->wakeup_count, ws->expire_count,
 843                         ktime_to_ms(active_time), ktime_to_ms(total_time),
 844                         ktime_to_ms(max_time), ktime_to_ms(ws->last_time),
 845                         ktime_to_ms(prevent_sleep_time));
 846
 847         spin_unlock_irqrestore(&ws->lock, flags);
 848
 849         return ret;
 850 }
 851
 852 /**
 853  * wakeup_sources_stats_show - Print wakeup sources statistics information.
 854  * @m: seq_file to print the statistics into.
 855  */
 856 static int wakeup_sources_stats_show(struct seq_file *m, void *unused)
 857 {
 858         struct wakeup_source *ws;
 859
 860         seq_puts(m, "name\t\tactive_count\tevent_count\twakeup_count\t"
 861                 "expire_count\tactive_since\ttotal_time\tmax_time\t"
 862                 "last_change\tprevent_suspend_time\n");
 863
 864         rcu_read_lock();
 865         list_for_each_entry_rcu(ws, &wakeup_sources, entry)
 866                 print_wakeup_source_stats(m, ws);
 867         rcu_read_unlock();
 868
 869         return 0;
 870 }
 871
 872 static int wakeup_sources_stats_open(struct inode *inode, struct file *file)
 873 {
 874         return single_open(file, wakeup_sources_stats_show, NULL);
 875 }
 876
 877 static const struct file_operations wakeup_sources_stats_fops = {
 878         .owner = THIS_MODULE,
 879         .open = wakeup_sources_stats_open,
 880         .read = seq_read,
 881         .llseek = seq_lseek,
 882         .release = single_release,
 883 };
 884
 885 static int __init wakeup_sources_debugfs_init(void)
 886 {
 887         wakeup_sources_stats_dentry = debugfs_create_file("wakeup_sources",
 888                         S_IRUGO, NULL, NULL, &wakeup_sources_stats_fops);
 889         return 0;
 890 }
 891
 892 postcore_initcall(wakeup_sources_debugfs_init);