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/pm_wakeirq.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 /* If set and the system is suspending, terminate the suspend. */
  29 static bool pm_abort_suspend __read_mostly;
  30
  31 /*
  32  * Combined counters of registered wakeup events and wakeup events in progress.
  33  * They need to be modified together atomically, so it's better to use one
  34  * atomic variable to hold them both.
  35  */
  36 static atomic_t combined_event_count = ATOMIC_INIT(0);
  37
  38 #define IN_PROGRESS_BITS        (sizeof(int) * 4)
  39 #define MAX_IN_PROGRESS         ((1 << IN_PROGRESS_BITS) - 1)
  40
  41 static void split_counters(unsigned int *cnt, unsigned int *inpr)
  42 {
  43         unsigned int comb = atomic_read(&combined_event_count);
  44
  45         *cnt = (comb >> IN_PROGRESS_BITS);
  46         *inpr = comb & MAX_IN_PROGRESS;
  47 }
  48
  49 /* A preserved old value of the events counter. */
  50 static unsigned int saved_count;
  51
  52 static DEFINE_SPINLOCK(events_lock);
  53
  54 static void pm_wakeup_timer_fn(unsigned long data);
  55
  56 static LIST_HEAD(wakeup_sources);
  57
  58 static DECLARE_WAIT_QUEUE_HEAD(wakeup_count_wait_queue);
  59
  60 static struct wakeup_source deleted_ws = {
  61         .name = "deleted",
  62         .lock =  __SPIN_LOCK_UNLOCKED(deleted_ws.lock),
  63 };
  64
  65 /**
  66  * wakeup_source_prepare - Prepare a new wakeup source for initialization.
  67  * @ws: Wakeup source to prepare.
  68  * @name: Pointer to the name of the new wakeup source.
  69  *
  70  * Callers must ensure that the @name string won't be freed when @ws is still in
  71  * use.
  72  */
  73 void wakeup_source_prepare(struct wakeup_source *ws, const char *name)
  74 {
  75         if (ws) {
  76                 memset(ws, 0, sizeof(*ws));
  77                 ws->name = name;
  78         }
  79 }
  80 EXPORT_SYMBOL_GPL(wakeup_source_prepare);
  81
  82 /**
  83  * wakeup_source_create - Create a struct wakeup_source object.
  84  * @name: Name of the new wakeup source.
  85  */
  86 struct wakeup_source *wakeup_source_create(const char *name)
  87 {
  88         struct wakeup_source *ws;
  89
  90         ws = kmalloc(sizeof(*ws), GFP_KERNEL);
  91         if (!ws)
  92                 return NULL;
  93
  94         wakeup_source_prepare(ws, name ? kstrdup(name, GFP_KERNEL) : NULL);
  95         return ws;
  96 }
  97 EXPORT_SYMBOL_GPL(wakeup_source_create);
  98
  99 /**
 100  * wakeup_source_drop - Prepare a struct wakeup_source object for destruction.
 101  * @ws: Wakeup source to prepare for destruction.
 102  *
 103  * Callers must ensure that __pm_stay_awake() or __pm_wakeup_event() will never
 104  * be run in parallel with this function for the same wakeup source object.
 105  */
 106 void wakeup_source_drop(struct wakeup_source *ws)
 107 {
 108         if (!ws)
 109                 return;
 110
 111         del_timer_sync(&ws->timer);
 112         __pm_relax(ws);
 113 }
 114 EXPORT_SYMBOL_GPL(wakeup_source_drop);
 115
 116 /*
 117  * Record wakeup_source statistics being deleted into a dummy wakeup_source.
 118  */
 119 static void wakeup_source_record(struct wakeup_source *ws)
 120 {
 121         unsigned long flags;
 122
 123         spin_lock_irqsave(&deleted_ws.lock, flags);
 124
 125         if (ws->event_count) {
 126                 deleted_ws.total_time =
 127                         ktime_add(deleted_ws.total_time, ws->total_time);
 128                 deleted_ws.prevent_sleep_time =
 129                         ktime_add(deleted_ws.prevent_sleep_time,
 130                                   ws->prevent_sleep_time);
 131                 deleted_ws.max_time =
 132                         ktime_compare(deleted_ws.max_time, ws->max_time) > 0 ?
 133                                 deleted_ws.max_time : ws->max_time;
 134                 deleted_ws.event_count += ws->event_count;
 135                 deleted_ws.active_count += ws->active_count;
 136                 deleted_ws.relax_count += ws->relax_count;
 137                 deleted_ws.expire_count += ws->expire_count;
 138                 deleted_ws.wakeup_count += ws->wakeup_count;
 139         }
 140
 141         spin_unlock_irqrestore(&deleted_ws.lock, flags);
 142 }
 143
 144 /**
 145  * wakeup_source_destroy - Destroy a struct wakeup_source object.
 146  * @ws: Wakeup source to destroy.
 147  *
 148  * Use only for wakeup source objects created with wakeup_source_create().
 149  */
 150 void wakeup_source_destroy(struct wakeup_source *ws)
 151 {
 152         if (!ws)
 153                 return;
 154
 155         wakeup_source_drop(ws);
 156         wakeup_source_record(ws);
 157         kfree(ws->name);
 158         kfree(ws);
 159 }
 160 EXPORT_SYMBOL_GPL(wakeup_source_destroy);
 161
 162 /**
 163  * wakeup_source_add - Add given object to the list of wakeup sources.
 164  * @ws: Wakeup source object to add to the list.
 165  */
 166 void wakeup_source_add(struct wakeup_source *ws)
 167 {
 168         unsigned long flags;
 169
 170         if (WARN_ON(!ws))
 171                 return;
 172
 173         spin_lock_init(&ws->lock);
 174         setup_timer(&ws->timer, pm_wakeup_timer_fn, (unsigned long)ws);
 175         ws->active = false;
 176         ws->last_time = ktime_get();
 177
 178         spin_lock_irqsave(&events_lock, flags);
 179         list_add_rcu(&ws->entry, &wakeup_sources);
 180         spin_unlock_irqrestore(&events_lock, flags);
 181 }
 182 EXPORT_SYMBOL_GPL(wakeup_source_add);
 183
 184 /**
 185  * wakeup_source_remove - Remove given object from the wakeup sources list.
 186  * @ws: Wakeup source object to remove from the list.
 187  */
 188 void wakeup_source_remove(struct wakeup_source *ws)
 189 {
 190         unsigned long flags;
 191
 192         if (WARN_ON(!ws))
 193                 return;
 194
 195         spin_lock_irqsave(&events_lock, flags);
 196         list_del_rcu(&ws->entry);
 197         spin_unlock_irqrestore(&events_lock, flags);
 198         synchronize_rcu();
 199 }
 200 EXPORT_SYMBOL_GPL(wakeup_source_remove);
 201
 202 /**
 203  * wakeup_source_register - Create wakeup source and add it to the list.
 204  * @name: Name of the wakeup source to register.
 205  */
 206 struct wakeup_source *wakeup_source_register(const char *name)
 207 {
 208         struct wakeup_source *ws;
 209
 210         ws = wakeup_source_create(name);
 211         if (ws)
 212                 wakeup_source_add(ws);
 213
 214         return ws;
 215 }
 216 EXPORT_SYMBOL_GPL(wakeup_source_register);
 217
 218 /**
 219  * wakeup_source_unregister - Remove wakeup source from the list and remove it.
 220  * @ws: Wakeup source object to unregister.
 221  */
 222 void wakeup_source_unregister(struct wakeup_source *ws)
 223 {
 224         if (ws) {
 225                 wakeup_source_remove(ws);
 226                 wakeup_source_destroy(ws);
 227         }
 228 }
 229 EXPORT_SYMBOL_GPL(wakeup_source_unregister);
 230
 231 /**
 232  * device_wakeup_attach - Attach a wakeup source object to a device object.
 233  * @dev: Device to handle.
 234  * @ws: Wakeup source object to attach to @dev.
 235  *
 236  * This causes @dev to be treated as a wakeup device.
 237  */
 238 static int device_wakeup_attach(struct device *dev, struct wakeup_source *ws)
 239 {
 240         spin_lock_irq(&dev->power.lock);
 241         if (dev->power.wakeup) {
 242                 spin_unlock_irq(&dev->power.lock);
 243                 return -EEXIST;
 244         }
 245         dev->power.wakeup = ws;
 246         spin_unlock_irq(&dev->power.lock);
 247         return 0;
 248 }
 249
 250 /**
 251  * device_wakeup_enable - Enable given device to be a wakeup source.
 252  * @dev: Device to handle.
 253  *
 254  * Create a wakeup source object, register it and attach it to @dev.
 255  */
 256 int device_wakeup_enable(struct device *dev)
 257 {
 258         struct wakeup_source *ws;
 259         int ret;
 260
 261         if (!dev || !dev->power.can_wakeup)
 262                 return -EINVAL;
 263
 264         ws = wakeup_source_register(dev_name(dev));
 265         if (!ws)
 266                 return -ENOMEM;
 267
 268         ret = device_wakeup_attach(dev, ws);
 269         if (ret)
 270                 wakeup_source_unregister(ws);
 271
 272         return ret;
 273 }
 274 EXPORT_SYMBOL_GPL(device_wakeup_enable);
 275
 276 /**
 277  * device_wakeup_attach_irq - Attach a wakeirq to a wakeup source
 278  * @dev: Device to handle
 279  * @wakeirq: Device specific wakeirq entry
 280  *
 281  * Attach a device wakeirq to the wakeup source so the device
 282  * wake IRQ can be configured automatically for suspend and
 283  * resume.
 284  */
 285 int device_wakeup_attach_irq(struct device *dev,
 286                              struct wake_irq *wakeirq)
 287 {
 288         struct wakeup_source *ws;
 289         int ret = 0;
 290
 291         spin_lock_irq(&dev->power.lock);
 292         ws = dev->power.wakeup;
 293         if (!ws) {
 294                 dev_err(dev, "forgot to call call device_init_wakeup?\n");
 295                 ret = -EINVAL;
 296                 goto unlock;
 297         }
 298
 299         if (ws->wakeirq) {
 300                 ret = -EEXIST;
 301                 goto unlock;
 302         }
 303
 304         ws->wakeirq = wakeirq;
 305
 306 unlock:
 307         spin_unlock_irq(&dev->power.lock);
 308
 309         return ret;
 310 }
 311
 312 /**
 313  * device_wakeup_detach_irq - Detach a wakeirq from a wakeup source
 314  * @dev: Device to handle
 315  *
 316  * Removes a device wakeirq from the wakeup source.
 317  */
 318 void device_wakeup_detach_irq(struct device *dev)
 319 {
 320         struct wakeup_source *ws;
 321
 322         spin_lock_irq(&dev->power.lock);
 323         ws = dev->power.wakeup;
 324         if (!ws)
 325                 goto unlock;
 326
 327         ws->wakeirq = NULL;
 328
 329 unlock:
 330         spin_unlock_irq(&dev->power.lock);
 331 }
 332
 333 /**
 334  * device_wakeup_arm_wake_irqs(void)
 335  *
 336  * Itereates over the list of device wakeirqs to arm them.
 337  */
 338 void device_wakeup_arm_wake_irqs(void)
 339 {
 340         struct wakeup_source *ws;
 341
 342         rcu_read_lock();
 343         list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
 344                 if (ws->wakeirq)
 345                         dev_pm_arm_wake_irq(ws->wakeirq);
 346         }
 347         rcu_read_unlock();
 348 }
 349
 350 /**
 351  * device_wakeup_disarm_wake_irqs(void)
 352  *
 353  * Itereates over the list of device wakeirqs to disarm them.
 354  */
 355 void device_wakeup_disarm_wake_irqs(void)
 356 {
 357         struct wakeup_source *ws;
 358
 359         rcu_read_lock();
 360         list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
 361                 if (ws->wakeirq)
 362                         dev_pm_disarm_wake_irq(ws->wakeirq);
 363         }
 364         rcu_read_unlock();
 365 }
 366
 367 /**
 368  * device_wakeup_detach - Detach a device's wakeup source object from it.
 369  * @dev: Device to detach the wakeup source object from.
 370  *
 371  * After it returns, @dev will not be treated as a wakeup device any more.
 372  */
 373 static struct wakeup_source *device_wakeup_detach(struct device *dev)
 374 {
 375         struct wakeup_source *ws;
 376
 377         spin_lock_irq(&dev->power.lock);
 378         ws = dev->power.wakeup;
 379         dev->power.wakeup = NULL;
 380         spin_unlock_irq(&dev->power.lock);
 381         return ws;
 382 }
 383
 384 /**
 385  * device_wakeup_disable - Do not regard a device as a wakeup source any more.
 386  * @dev: Device to handle.
 387  *
 388  * Detach the @dev's wakeup source object from it, unregister this wakeup source
 389  * object and destroy it.
 390  */
 391 int device_wakeup_disable(struct device *dev)
 392 {
 393         struct wakeup_source *ws;
 394
 395         if (!dev || !dev->power.can_wakeup)
 396                 return -EINVAL;
 397
 398         ws = device_wakeup_detach(dev);
 399         if (ws)
 400                 wakeup_source_unregister(ws);
 401
 402         return 0;
 403 }
 404 EXPORT_SYMBOL_GPL(device_wakeup_disable);
 405
 406 /**
 407  * device_set_wakeup_capable - Set/reset device wakeup capability flag.
 408  * @dev: Device to handle.
 409  * @capable: Whether or not @dev is capable of waking up the system from sleep.
 410  *
 411  * If @capable is set, set the @dev's power.can_wakeup flag and add its
 412  * wakeup-related attributes to sysfs.  Otherwise, unset the @dev's
 413  * power.can_wakeup flag and remove its wakeup-related attributes from sysfs.
 414  *
 415  * This function may sleep and it can't be called from any context where
 416  * sleeping is not allowed.
 417  */
 418 void device_set_wakeup_capable(struct device *dev, bool capable)
 419 {
 420         if (!!dev->power.can_wakeup == !!capable)
 421                 return;
 422
 423         if (device_is_registered(dev) && !list_empty(&dev->power.entry)) {
 424                 if (capable) {
 425                         if (wakeup_sysfs_add(dev))
 426                                 return;
 427                 } else {
 428                         wakeup_sysfs_remove(dev);
 429                 }
 430         }
 431         dev->power.can_wakeup = capable;
 432 }
 433 EXPORT_SYMBOL_GPL(device_set_wakeup_capable);
 434
 435 /**
 436  * device_init_wakeup - Device wakeup initialization.
 437  * @dev: Device to handle.
 438  * @enable: Whether or not to enable @dev as a wakeup device.
 439  *
 440  * By default, most devices should leave wakeup disabled.  The exceptions are
 441  * devices that everyone expects to be wakeup sources: keyboards, power buttons,
 442  * possibly network interfaces, etc.  Also, devices that don't generate their
 443  * own wakeup requests but merely forward requests from one bus to another
 444  * (like PCI bridges) should have wakeup enabled by default.
 445  */
 446 int device_init_wakeup(struct device *dev, bool enable)
 447 {
 448         int ret = 0;
 449
 450         if (!dev)
 451                 return -EINVAL;
 452
 453         if (enable) {
 454                 device_set_wakeup_capable(dev, true);
 455                 ret = device_wakeup_enable(dev);
 456         } else {
 457                 if (dev->power.can_wakeup)
 458                         device_wakeup_disable(dev);
 459
 460                 device_set_wakeup_capable(dev, false);
 461         }
 462
 463         return ret;
 464 }
 465 EXPORT_SYMBOL_GPL(device_init_wakeup);
 466
 467 /**
 468  * device_set_wakeup_enable - Enable or disable a device to wake up the system.
 469  * @dev: Device to handle.
 470  */
 471 int device_set_wakeup_enable(struct device *dev, bool enable)
 472 {
 473         if (!dev || !dev->power.can_wakeup)
 474                 return -EINVAL;
 475
 476         return enable ? device_wakeup_enable(dev) : device_wakeup_disable(dev);
 477 }
 478 EXPORT_SYMBOL_GPL(device_set_wakeup_enable);
 479
 480 /**
 481  * wakeup_source_not_registered - validate the given wakeup source.
 482  * @ws: Wakeup source to be validated.
 483  */
 484 static bool wakeup_source_not_registered(struct wakeup_source *ws)
 485 {
 486         /*
 487          * Use timer struct to check if the given source is initialized
 488          * by wakeup_source_add.
 489          */
 490         return ws->timer.function != pm_wakeup_timer_fn ||
 491                    ws->timer.data != (unsigned long)ws;
 492 }
 493
 494 /*
 495  * The functions below use the observation that each wakeup event starts a
 496  * period in which the system should not be suspended.  The moment this period
 497  * will end depends on how the wakeup event is going to be processed after being
 498  * detected and all of the possible cases can be divided into two distinct
 499  * groups.
 500  *
 501  * First, a wakeup event may be detected by the same functional unit that will
 502  * carry out the entire processing of it and possibly will pass it to user space
 503  * for further processing.  In that case the functional unit that has detected
 504  * the event may later "close" the "no suspend" period associated with it
 505  * directly as soon as it has been dealt with.  The pair of pm_stay_awake() and
 506  * pm_relax(), balanced with each other, is supposed to be used in such
 507  * situations.
 508  *
 509  * Second, a wakeup event may be detected by one functional unit and processed
 510  * by another one.  In that case the unit that has detected it cannot really
 511  * "close" the "no suspend" period associated with it, unless it knows in
 512  * advance what's going to happen to the event during processing.  This
 513  * knowledge, however, may not be available to it, so it can simply specify time
 514  * to wait before the system can be suspended and pass it as the second
 515  * argument of pm_wakeup_event().
 516  *
 517  * It is valid to call pm_relax() after pm_wakeup_event(), in which case the
 518  * "no suspend" period will be ended either by the pm_relax(), or by the timer
 519  * function executed when the timer expires, whichever comes first.
 520  */
 521
 522 /**
 523  * wakup_source_activate - Mark given wakeup source as active.
 524  * @ws: Wakeup source to handle.
 525  *
 526  * Update the @ws' statistics and, if @ws has just been activated, notify the PM
 527  * core of the event by incrementing the counter of of wakeup events being
 528  * processed.
 529  */
 530 static void wakeup_source_activate(struct wakeup_source *ws)
 531 {
 532         unsigned int cec;
 533
 534         if (WARN_ONCE(wakeup_source_not_registered(ws),
 535                         "unregistered wakeup source\n"))
 536                 return;
 537
 538         /*
 539          * active wakeup source should bring the system
 540          * out of PM_SUSPEND_FREEZE state
 541          */
 542         freeze_wake();
 543
 544         ws->active = true;
 545         ws->active_count++;
 546         ws->last_time = ktime_get();
 547         if (ws->autosleep_enabled)
 548                 ws->start_prevent_time = ws->last_time;
 549
 550         /* Increment the counter of events in progress. */
 551         cec = atomic_inc_return(&combined_event_count);
 552
 553         trace_wakeup_source_activate(ws->name, cec);
 554 }
 555
 556 /**
 557  * wakeup_source_report_event - Report wakeup event using the given source.
 558  * @ws: Wakeup source to report the event for.
 559  */
 560 static void wakeup_source_report_event(struct wakeup_source *ws)
 561 {
 562         ws->event_count++;
 563         /* This is racy, but the counter is approximate anyway. */
 564         if (events_check_enabled)
 565                 ws->wakeup_count++;
 566
 567         if (!ws->active)
 568                 wakeup_source_activate(ws);
 569 }
 570
 571 /**
 572  * __pm_stay_awake - Notify the PM core of a wakeup event.
 573  * @ws: Wakeup source object associated with the source of the event.
 574  *
 575  * It is safe to call this function from interrupt context.
 576  */
 577 void __pm_stay_awake(struct wakeup_source *ws)
 578 {
 579         unsigned long flags;
 580
 581         if (!ws)
 582                 return;
 583
 584         spin_lock_irqsave(&ws->lock, flags);
 585
 586         wakeup_source_report_event(ws);
 587         del_timer(&ws->timer);
 588         ws->timer_expires = 0;
 589
 590         spin_unlock_irqrestore(&ws->lock, flags);
 591 }
 592 EXPORT_SYMBOL_GPL(__pm_stay_awake);
 593
 594 /**
 595  * pm_stay_awake - Notify the PM core that a wakeup event is being processed.
 596  * @dev: Device the wakeup event is related to.
 597  *
 598  * Notify the PM core of a wakeup event (signaled by @dev) by calling
 599  * __pm_stay_awake for the @dev's wakeup source object.
 600  *
 601  * Call this function after detecting of a wakeup event if pm_relax() is going
 602  * to be called directly after processing the event (and possibly passing it to
 603  * user space for further processing).
 604  */
 605 void pm_stay_awake(struct device *dev)
 606 {
 607         unsigned long flags;
 608
 609         if (!dev)
 610                 return;
 611
 612         spin_lock_irqsave(&dev->power.lock, flags);
 613         __pm_stay_awake(dev->power.wakeup);
 614         spin_unlock_irqrestore(&dev->power.lock, flags);
 615 }
 616 EXPORT_SYMBOL_GPL(pm_stay_awake);
 617
 618 #ifdef CONFIG_PM_AUTOSLEEP
 619 static void update_prevent_sleep_time(struct wakeup_source *ws, ktime_t now)
 620 {
 621         ktime_t delta = ktime_sub(now, ws->start_prevent_time);
 622         ws->prevent_sleep_time = ktime_add(ws->prevent_sleep_time, delta);
 623 }
 624 #else
 625 static inline void update_prevent_sleep_time(struct wakeup_source *ws,
 626                                              ktime_t now) {}
 627 #endif
 628
 629 /**
 630  * wakup_source_deactivate - Mark given wakeup source as inactive.
 631  * @ws: Wakeup source to handle.
 632  *
 633  * Update the @ws' statistics and notify the PM core that the wakeup source has
 634  * become inactive by decrementing the counter of wakeup events being processed
 635  * and incrementing the counter of registered wakeup events.
 636  */
 637 static void wakeup_source_deactivate(struct wakeup_source *ws)
 638 {
 639         unsigned int cnt, inpr, cec;
 640         ktime_t duration;
 641         ktime_t now;
 642
 643         ws->relax_count++;
 644         /*
 645          * __pm_relax() may be called directly or from a timer function.
 646          * If it is called directly right after the timer function has been
 647          * started, but before the timer function calls __pm_relax(), it is
 648          * possible that __pm_stay_awake() will be called in the meantime and
 649          * will set ws->active.  Then, ws->active may be cleared immediately
 650          * by the __pm_relax() called from the timer function, but in such a
 651          * case ws->relax_count will be different from ws->active_count.
 652          */
 653         if (ws->relax_count != ws->active_count) {
 654                 ws->relax_count--;
 655                 return;
 656         }
 657
 658         ws->active = false;
 659
 660         now = ktime_get();
 661         duration = ktime_sub(now, ws->last_time);
 662         ws->total_time = ktime_add(ws->total_time, duration);
 663         if (ktime_to_ns(duration) > ktime_to_ns(ws->max_time))
 664                 ws->max_time = duration;
 665
 666         ws->last_time = now;
 667         del_timer(&ws->timer);
 668         ws->timer_expires = 0;
 669
 670         if (ws->autosleep_enabled)
 671                 update_prevent_sleep_time(ws, now);
 672
 673         /*
 674          * Increment the counter of registered wakeup events and decrement the
 675          * couter of wakeup events in progress simultaneously.
 676          */
 677         cec = atomic_add_return(MAX_IN_PROGRESS, &combined_event_count);
 678         trace_wakeup_source_deactivate(ws->name, cec);
 679
 680         split_counters(&cnt, &inpr);
 681         if (!inpr && waitqueue_active(&wakeup_count_wait_queue))
 682                 wake_up(&wakeup_count_wait_queue);
 683 }
 684
 685 /**
 686  * __pm_relax - Notify the PM core that processing of a wakeup event has ended.
 687  * @ws: Wakeup source object associated with the source of the event.
 688  *
 689  * Call this function for wakeup events whose processing started with calling
 690  * __pm_stay_awake().
 691  *
 692  * It is safe to call it from interrupt context.
 693  */
 694 void __pm_relax(struct wakeup_source *ws)
 695 {
 696         unsigned long flags;
 697
 698         if (!ws)
 699                 return;
 700
 701         spin_lock_irqsave(&ws->lock, flags);
 702         if (ws->active)
 703                 wakeup_source_deactivate(ws);
 704         spin_unlock_irqrestore(&ws->lock, flags);
 705 }
 706 EXPORT_SYMBOL_GPL(__pm_relax);
 707
 708 /**
 709  * pm_relax - Notify the PM core that processing of a wakeup event has ended.
 710  * @dev: Device that signaled the event.
 711  *
 712  * Execute __pm_relax() for the @dev's wakeup source object.
 713  */
 714 void pm_relax(struct device *dev)
 715 {
 716         unsigned long flags;
 717
 718         if (!dev)
 719                 return;
 720
 721         spin_lock_irqsave(&dev->power.lock, flags);
 722         __pm_relax(dev->power.wakeup);
 723         spin_unlock_irqrestore(&dev->power.lock, flags);
 724 }
 725 EXPORT_SYMBOL_GPL(pm_relax);
 726
 727 /**
 728  * pm_wakeup_timer_fn - Delayed finalization of a wakeup event.
 729  * @data: Address of the wakeup source object associated with the event source.
 730  *
 731  * Call wakeup_source_deactivate() for the wakeup source whose address is stored
 732  * in @data if it is currently active and its timer has not been canceled and
 733  * the expiration time of the timer is not in future.
 734  */
 735 static void pm_wakeup_timer_fn(unsigned long data)
 736 {
 737         struct wakeup_source *ws = (struct wakeup_source *)data;
 738         unsigned long flags;
 739
 740         spin_lock_irqsave(&ws->lock, flags);
 741
 742         if (ws->active && ws->timer_expires
 743             && time_after_eq(jiffies, ws->timer_expires)) {
 744                 wakeup_source_deactivate(ws);
 745                 ws->expire_count++;
 746         }
 747
 748         spin_unlock_irqrestore(&ws->lock, flags);
 749 }
 750
 751 /**
 752  * __pm_wakeup_event - Notify the PM core of a wakeup event.
 753  * @ws: Wakeup source object associated with the event source.
 754  * @msec: Anticipated event processing time (in milliseconds).
 755  *
 756  * Notify the PM core of a wakeup event whose source is @ws that will take
 757  * approximately @msec milliseconds to be processed by the kernel.  If @ws is
 758  * not active, activate it.  If @msec is nonzero, set up the @ws' timer to
 759  * execute pm_wakeup_timer_fn() in future.
 760  *
 761  * It is safe to call this function from interrupt context.
 762  */
 763 void __pm_wakeup_event(struct wakeup_source *ws, unsigned int msec)
 764 {
 765         unsigned long flags;
 766         unsigned long expires;
 767
 768         if (!ws)
 769                 return;
 770
 771         spin_lock_irqsave(&ws->lock, flags);
 772
 773         wakeup_source_report_event(ws);
 774
 775         if (!msec) {
 776                 wakeup_source_deactivate(ws);
 777                 goto unlock;
 778         }
 779
 780         expires = jiffies + msecs_to_jiffies(msec);
 781         if (!expires)
 782                 expires = 1;
 783
 784         if (!ws->timer_expires || time_after(expires, ws->timer_expires)) {
 785                 mod_timer(&ws->timer, expires);
 786                 ws->timer_expires = expires;
 787         }
 788
 789  unlock:
 790         spin_unlock_irqrestore(&ws->lock, flags);
 791 }
 792 EXPORT_SYMBOL_GPL(__pm_wakeup_event);
 793
 794
 795 /**
 796  * pm_wakeup_event - Notify the PM core of a wakeup event.
 797  * @dev: Device the wakeup event is related to.
 798  * @msec: Anticipated event processing time (in milliseconds).
 799  *
 800  * Call __pm_wakeup_event() for the @dev's wakeup source object.
 801  */
 802 void pm_wakeup_event(struct device *dev, unsigned int msec)
 803 {
 804         unsigned long flags;
 805
 806         if (!dev)
 807                 return;
 808
 809         spin_lock_irqsave(&dev->power.lock, flags);
 810         __pm_wakeup_event(dev->power.wakeup, msec);
 811         spin_unlock_irqrestore(&dev->power.lock, flags);
 812 }
 813 EXPORT_SYMBOL_GPL(pm_wakeup_event);
 814
 815 void pm_print_active_wakeup_sources(void)
 816 {
 817         struct wakeup_source *ws;
 818         int active = 0;
 819         struct wakeup_source *last_activity_ws = NULL;
 820
 821         rcu_read_lock();
 822         list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
 823                 if (ws->active) {
 824                         pr_info("active wakeup source: %s\n", ws->name);
 825                         active = 1;
 826                 } else if (!active &&
 827                            (!last_activity_ws ||
 828                             ktime_to_ns(ws->last_time) >
 829                             ktime_to_ns(last_activity_ws->last_time))) {
 830                         last_activity_ws = ws;
 831                 }
 832         }
 833
 834         if (!active && last_activity_ws)
 835                 pr_info("last active wakeup source: %s\n",
 836                         last_activity_ws->name);
 837         rcu_read_unlock();
 838 }
 839 EXPORT_SYMBOL_GPL(pm_print_active_wakeup_sources);
 840
 841 /**
 842  * pm_wakeup_pending - Check if power transition in progress should be aborted.
 843  *
 844  * Compare the current number of registered wakeup events with its preserved
 845  * value from the past and return true if new wakeup events have been registered
 846  * since the old value was stored.  Also return true if the current number of
 847  * wakeup events being processed is different from zero.
 848  */
 849 bool pm_wakeup_pending(void)
 850 {
 851         unsigned long flags;
 852         bool ret = false;
 853
 854         spin_lock_irqsave(&events_lock, flags);
 855         if (events_check_enabled) {
 856                 unsigned int cnt, inpr;
 857
 858                 split_counters(&cnt, &inpr);
 859                 ret = (cnt != saved_count || inpr > 0);
 860                 events_check_enabled = !ret;
 861         }
 862         spin_unlock_irqrestore(&events_lock, flags);
 863
 864         if (ret) {
 865                 pr_info("PM: Wakeup pending, aborting suspend\n");
 866                 pm_print_active_wakeup_sources();
 867         }
 868
 869         return ret || pm_abort_suspend;
 870 }
 871
 872 void pm_system_wakeup(void)
 873 {
 874         pm_abort_suspend = true;
 875         freeze_wake();
 876 }
 877 EXPORT_SYMBOL_GPL(pm_system_wakeup);
 878
 879 void pm_wakeup_clear(void)
 880 {
 881         pm_abort_suspend = false;
 882 }
 883
 884 /**
 885  * pm_get_wakeup_count - Read the number of registered wakeup events.
 886  * @count: Address to store the value at.
 887  * @block: Whether or not to block.
 888  *
 889  * Store the number of registered wakeup events at the address in @count.  If
 890  * @block is set, block until the current number of wakeup events being
 891  * processed is zero.
 892  *
 893  * Return 'false' if the current number of wakeup events being processed is
 894  * nonzero.  Otherwise return 'true'.
 895  */
 896 bool pm_get_wakeup_count(unsigned int *count, bool block)
 897 {
 898         unsigned int cnt, inpr;
 899
 900         if (block) {
 901                 DEFINE_WAIT(wait);
 902
 903                 for (;;) {
 904                         prepare_to_wait(&wakeup_count_wait_queue, &wait,
 905                                         TASK_INTERRUPTIBLE);
 906                         split_counters(&cnt, &inpr);
 907                         if (inpr == 0 || signal_pending(current))
 908                                 break;
 909
 910                         schedule();
 911                 }
 912                 finish_wait(&wakeup_count_wait_queue, &wait);
 913         }
 914
 915         split_counters(&cnt, &inpr);
 916         *count = cnt;
 917         return !inpr;
 918 }
 919
 920 /**
 921  * pm_save_wakeup_count - Save the current number of registered wakeup events.
 922  * @count: Value to compare with the current number of registered wakeup events.
 923  *
 924  * If @count is equal to the current number of registered wakeup events and the
 925  * current number of wakeup events being processed is zero, store @count as the
 926  * old number of registered wakeup events for pm_check_wakeup_events(), enable
 927  * wakeup events detection and return 'true'.  Otherwise disable wakeup events
 928  * detection and return 'false'.
 929  */
 930 bool pm_save_wakeup_count(unsigned int count)
 931 {
 932         unsigned int cnt, inpr;
 933         unsigned long flags;
 934
 935         events_check_enabled = false;
 936         spin_lock_irqsave(&events_lock, flags);
 937         split_counters(&cnt, &inpr);
 938         if (cnt == count && inpr == 0) {
 939                 saved_count = count;
 940                 events_check_enabled = true;
 941         }
 942         spin_unlock_irqrestore(&events_lock, flags);
 943         return events_check_enabled;
 944 }
 945
 946 #ifdef CONFIG_PM_AUTOSLEEP
 947 /**
 948  * pm_wakep_autosleep_enabled - Modify autosleep_enabled for all wakeup sources.
 949  * @enabled: Whether to set or to clear the autosleep_enabled flags.
 950  */
 951 void pm_wakep_autosleep_enabled(bool set)
 952 {
 953         struct wakeup_source *ws;
 954         ktime_t now = ktime_get();
 955
 956         rcu_read_lock();
 957         list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
 958                 spin_lock_irq(&ws->lock);
 959                 if (ws->autosleep_enabled != set) {
 960                         ws->autosleep_enabled = set;
 961                         if (ws->active) {
 962                                 if (set)
 963                                         ws->start_prevent_time = now;
 964                                 else
 965                                         update_prevent_sleep_time(ws, now);
 966                         }
 967                 }
 968                 spin_unlock_irq(&ws->lock);
 969         }
 970         rcu_read_unlock();
 971 }
 972 #endif /* CONFIG_PM_AUTOSLEEP */
 973
 974 static struct dentry *wakeup_sources_stats_dentry;
 975
 976 /**
 977  * print_wakeup_source_stats - Print wakeup source statistics information.
 978  * @m: seq_file to print the statistics into.
 979  * @ws: Wakeup source object to print the statistics for.
 980  */
 981 static int print_wakeup_source_stats(struct seq_file *m,
 982                                      struct wakeup_source *ws)
 983 {
 984         unsigned long flags;
 985         ktime_t total_time;
 986         ktime_t max_time;
 987         unsigned long active_count;
 988         ktime_t active_time;
 989         ktime_t prevent_sleep_time;
 990
 991         spin_lock_irqsave(&ws->lock, flags);
 992
 993         total_time = ws->total_time;
 994         max_time = ws->max_time;
 995         prevent_sleep_time = ws->prevent_sleep_time;
 996         active_count = ws->active_count;
 997         if (ws->active) {
 998                 ktime_t now = ktime_get();
 999
1000                 active_time = ktime_sub(now, ws->last_time);
1001                 total_time = ktime_add(total_time, active_time);
1002                 if (active_time.tv64 > max_time.tv64)
1003                         max_time = active_time;
1004
1005                 if (ws->autosleep_enabled)
1006                         prevent_sleep_time = ktime_add(prevent_sleep_time,
1007                                 ktime_sub(now, ws->start_prevent_time));
1008         } else {
1009                 active_time = ktime_set(0, 0);
1010         }
1011
1012         seq_printf(m, "%-12s\t%lu\t\t%lu\t\t%lu\t\t%lu\t\t%lld\t\t%lld\t\t%lld\t\t%lld\t\t%lld\n",
1013                    ws->name, active_count, ws->event_count,
1014                    ws->wakeup_count, ws->expire_count,
1015                    ktime_to_ms(active_time), ktime_to_ms(total_time),
1016                    ktime_to_ms(max_time), ktime_to_ms(ws->last_time),
1017                    ktime_to_ms(prevent_sleep_time));
1018
1019         spin_unlock_irqrestore(&ws->lock, flags);
1020
1021         return 0;
1022 }
1023
1024 /**
1025  * wakeup_sources_stats_show - Print wakeup sources statistics information.
1026  * @m: seq_file to print the statistics into.
1027  */
1028 static int wakeup_sources_stats_show(struct seq_file *m, void *unused)
1029 {
1030         struct wakeup_source *ws;
1031
1032         seq_puts(m, "name\t\tactive_count\tevent_count\twakeup_count\t"
1033                 "expire_count\tactive_since\ttotal_time\tmax_time\t"
1034                 "last_change\tprevent_suspend_time\n");
1035
1036         rcu_read_lock();
1037         list_for_each_entry_rcu(ws, &wakeup_sources, entry)
1038                 print_wakeup_source_stats(m, ws);
1039         rcu_read_unlock();
1040
1041         print_wakeup_source_stats(m, &deleted_ws);
1042
1043         return 0;
1044 }
1045
1046 static int wakeup_sources_stats_open(struct inode *inode, struct file *file)
1047 {
1048         return single_open(file, wakeup_sources_stats_show, NULL);
1049 }
1050
1051 static const struct file_operations wakeup_sources_stats_fops = {
1052         .owner = THIS_MODULE,
1053         .open = wakeup_sources_stats_open,
1054         .read = seq_read,
1055         .llseek = seq_lseek,
1056         .release = single_release,
1057 };
1058
1059 static int __init wakeup_sources_debugfs_init(void)
1060 {
1061         wakeup_sources_stats_dentry = debugfs_create_file("wakeup_sources",
1062                         S_IRUGO, NULL, NULL, &wakeup_sources_stats_fops);
1063         return 0;
1064 }
1065
1066 postcore_initcall(wakeup_sources_debugfs_init);