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 /* First wakeup IRQ seen by the kernel in the last cycle. */
  29 unsigned int pm_wakeup_irq __read_mostly;
  30
  31 /* If set and the system is suspending, terminate the suspend. */
  32 static bool pm_abort_suspend __read_mostly;
  33
  34 /*
  35  * Combined counters of registered wakeup events and wakeup events in progress.
  36  * They need to be modified together atomically, so it's better to use one
  37  * atomic variable to hold them both.
  38  */
  39 static atomic_t combined_event_count = ATOMIC_INIT(0);
  40
  41 #define IN_PROGRESS_BITS        (sizeof(int) * 4)
  42 #define MAX_IN_PROGRESS         ((1 << IN_PROGRESS_BITS) - 1)
  43
  44 static void split_counters(unsigned int *cnt, unsigned int *inpr)
  45 {
  46         unsigned int comb = atomic_read(&combined_event_count);
  47
  48         *cnt = (comb >> IN_PROGRESS_BITS);
  49         *inpr = comb & MAX_IN_PROGRESS;
  50 }
  51
  52 /* A preserved old value of the events counter. */
  53 static unsigned int saved_count;
  54
  55 static DEFINE_SPINLOCK(events_lock);
  56
  57 static void pm_wakeup_timer_fn(unsigned long data);
  58
  59 static LIST_HEAD(wakeup_sources);
  60
  61 static DECLARE_WAIT_QUEUE_HEAD(wakeup_count_wait_queue);
  62
  63 static struct wakeup_source deleted_ws = {
  64         .name = "deleted",
  65         .lock =  __SPIN_LOCK_UNLOCKED(deleted_ws.lock),
  66 };
  67
  68 /**
  69  * wakeup_source_prepare - Prepare a new wakeup source for initialization.
  70  * @ws: Wakeup source to prepare.
  71  * @name: Pointer to the name of the new wakeup source.
  72  *
  73  * Callers must ensure that the @name string won't be freed when @ws is still in
  74  * use.
  75  */
  76 void wakeup_source_prepare(struct wakeup_source *ws, const char *name)
  77 {
  78         if (ws) {
  79                 memset(ws, 0, sizeof(*ws));
  80                 ws->name = name;
  81         }
  82 }
  83 EXPORT_SYMBOL_GPL(wakeup_source_prepare);
  84
  85 /**
  86  * wakeup_source_create - Create a struct wakeup_source object.
  87  * @name: Name of the new wakeup source.
  88  */
  89 struct wakeup_source *wakeup_source_create(const char *name)
  90 {
  91         struct wakeup_source *ws;
  92
  93         ws = kmalloc(sizeof(*ws), GFP_KERNEL);
  94         if (!ws)
  95                 return NULL;
  96
  97         wakeup_source_prepare(ws, name ? kstrdup_const(name, GFP_KERNEL) : NULL);
  98         return ws;
  99 }
 100 EXPORT_SYMBOL_GPL(wakeup_source_create);
 101
 102 /**
 103  * wakeup_source_drop - Prepare a struct wakeup_source object for destruction.
 104  * @ws: Wakeup source to prepare for destruction.
 105  *
 106  * Callers must ensure that __pm_stay_awake() or __pm_wakeup_event() will never
 107  * be run in parallel with this function for the same wakeup source object.
 108  */
 109 void wakeup_source_drop(struct wakeup_source *ws)
 110 {
 111         if (!ws)
 112                 return;
 113
 114         del_timer_sync(&ws->timer);
 115         __pm_relax(ws);
 116 }
 117 EXPORT_SYMBOL_GPL(wakeup_source_drop);
 118
 119 /*
 120  * Record wakeup_source statistics being deleted into a dummy wakeup_source.
 121  */
 122 static void wakeup_source_record(struct wakeup_source *ws)
 123 {
 124         unsigned long flags;
 125
 126         spin_lock_irqsave(&deleted_ws.lock, flags);
 127
 128         if (ws->event_count) {
 129                 deleted_ws.total_time =
 130                         ktime_add(deleted_ws.total_time, ws->total_time);
 131                 deleted_ws.prevent_sleep_time =
 132                         ktime_add(deleted_ws.prevent_sleep_time,
 133                                   ws->prevent_sleep_time);
 134                 deleted_ws.max_time =
 135                         ktime_compare(deleted_ws.max_time, ws->max_time) > 0 ?
 136                                 deleted_ws.max_time : ws->max_time;
 137                 deleted_ws.event_count += ws->event_count;
 138                 deleted_ws.active_count += ws->active_count;
 139                 deleted_ws.relax_count += ws->relax_count;
 140                 deleted_ws.expire_count += ws->expire_count;
 141                 deleted_ws.wakeup_count += ws->wakeup_count;
 142         }
 143
 144         spin_unlock_irqrestore(&deleted_ws.lock, flags);
 145 }
 146
 147 /**
 148  * wakeup_source_destroy - Destroy a struct wakeup_source object.
 149  * @ws: Wakeup source to destroy.
 150  *
 151  * Use only for wakeup source objects created with wakeup_source_create().
 152  */
 153 void wakeup_source_destroy(struct wakeup_source *ws)
 154 {
 155         if (!ws)
 156                 return;
 157
 158         wakeup_source_drop(ws);
 159         wakeup_source_record(ws);
 160         kfree_const(ws->name);
 161         kfree(ws);
 162 }
 163 EXPORT_SYMBOL_GPL(wakeup_source_destroy);
 164
 165 /**
 166  * wakeup_source_add - Add given object to the list of wakeup sources.
 167  * @ws: Wakeup source object to add to the list.
 168  */
 169 void wakeup_source_add(struct wakeup_source *ws)
 170 {
 171         unsigned long flags;
 172
 173         if (WARN_ON(!ws))
 174                 return;
 175
 176         spin_lock_init(&ws->lock);
 177         setup_timer(&ws->timer, pm_wakeup_timer_fn, (unsigned long)ws);
 178         ws->active = false;
 179         ws->last_time = ktime_get();
 180
 181         spin_lock_irqsave(&events_lock, flags);
 182         list_add_rcu(&ws->entry, &wakeup_sources);
 183         spin_unlock_irqrestore(&events_lock, flags);
 184 }
 185 EXPORT_SYMBOL_GPL(wakeup_source_add);
 186
 187 /**
 188  * wakeup_source_remove - Remove given object from the wakeup sources list.
 189  * @ws: Wakeup source object to remove from the list.
 190  */
 191 void wakeup_source_remove(struct wakeup_source *ws)
 192 {
 193         unsigned long flags;
 194
 195         if (WARN_ON(!ws))
 196                 return;
 197
 198         spin_lock_irqsave(&events_lock, flags);
 199         list_del_rcu(&ws->entry);
 200         spin_unlock_irqrestore(&events_lock, flags);
 201         synchronize_rcu();
 202 }
 203 EXPORT_SYMBOL_GPL(wakeup_source_remove);
 204
 205 /**
 206  * wakeup_source_register - Create wakeup source and add it to the list.
 207  * @name: Name of the wakeup source to register.
 208  */
 209 struct wakeup_source *wakeup_source_register(const char *name)
 210 {
 211         struct wakeup_source *ws;
 212
 213         ws = wakeup_source_create(name);
 214         if (ws)
 215                 wakeup_source_add(ws);
 216
 217         return ws;
 218 }
 219 EXPORT_SYMBOL_GPL(wakeup_source_register);
 220
 221 /**
 222  * wakeup_source_unregister - Remove wakeup source from the list and remove it.
 223  * @ws: Wakeup source object to unregister.
 224  */
 225 void wakeup_source_unregister(struct wakeup_source *ws)
 226 {
 227         if (ws) {
 228                 wakeup_source_remove(ws);
 229                 wakeup_source_destroy(ws);
 230         }
 231 }
 232 EXPORT_SYMBOL_GPL(wakeup_source_unregister);
 233
 234 /**
 235  * device_wakeup_attach - Attach a wakeup source object to a device object.
 236  * @dev: Device to handle.
 237  * @ws: Wakeup source object to attach to @dev.
 238  *
 239  * This causes @dev to be treated as a wakeup device.
 240  */
 241 static int device_wakeup_attach(struct device *dev, struct wakeup_source *ws)
 242 {
 243         spin_lock_irq(&dev->power.lock);
 244         if (dev->power.wakeup) {
 245                 spin_unlock_irq(&dev->power.lock);
 246                 return -EEXIST;
 247         }
 248         dev->power.wakeup = ws;
 249         if (dev->power.wakeirq)
 250                 device_wakeup_attach_irq(dev, dev->power.wakeirq);
 251         spin_unlock_irq(&dev->power.lock);
 252         return 0;
 253 }
 254
 255 /**
 256  * device_wakeup_enable - Enable given device to be a wakeup source.
 257  * @dev: Device to handle.
 258  *
 259  * Create a wakeup source object, register it and attach it to @dev.
 260  */
 261 int device_wakeup_enable(struct device *dev)
 262 {
 263         struct wakeup_source *ws;
 264         int ret;
 265
 266         if (!dev || !dev->power.can_wakeup)
 267                 return -EINVAL;
 268
 269         ws = wakeup_source_register(dev_name(dev));
 270         if (!ws)
 271                 return -ENOMEM;
 272
 273         ret = device_wakeup_attach(dev, ws);
 274         if (ret)
 275                 wakeup_source_unregister(ws);
 276
 277         return ret;
 278 }
 279 EXPORT_SYMBOL_GPL(device_wakeup_enable);
 280
 281 /**
 282  * device_wakeup_attach_irq - Attach a wakeirq to a wakeup source
 283  * @dev: Device to handle
 284  * @wakeirq: Device specific wakeirq entry
 285  *
 286  * Attach a device wakeirq to the wakeup source so the device
 287  * wake IRQ can be configured automatically for suspend and
 288  * resume.
 289  *
 290  * Call under the device's power.lock lock.
 291  */
 292 int device_wakeup_attach_irq(struct device *dev,
 293                              struct wake_irq *wakeirq)
 294 {
 295         struct wakeup_source *ws;
 296
 297         ws = dev->power.wakeup;
 298         if (!ws) {
 299                 dev_err(dev, "forgot to call call device_init_wakeup?\n");
 300                 return -EINVAL;
 301         }
 302
 303         if (ws->wakeirq)
 304                 return -EEXIST;
 305
 306         ws->wakeirq = wakeirq;
 307         return 0;
 308 }
 309
 310 /**
 311  * device_wakeup_detach_irq - Detach a wakeirq from a wakeup source
 312  * @dev: Device to handle
 313  *
 314  * Removes a device wakeirq from the wakeup source.
 315  *
 316  * Call under the device's power.lock lock.
 317  */
 318 void device_wakeup_detach_irq(struct device *dev)
 319 {
 320         struct wakeup_source *ws;
 321
 322         ws = dev->power.wakeup;
 323         if (ws)
 324                 ws->wakeirq = NULL;
 325 }
 326
 327 /**
 328  * device_wakeup_arm_wake_irqs(void)
 329  *
 330  * Itereates over the list of device wakeirqs to arm them.
 331  */
 332 void device_wakeup_arm_wake_irqs(void)
 333 {
 334         struct wakeup_source *ws;
 335
 336         rcu_read_lock();
 337         list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
 338                 if (ws->wakeirq)
 339                         dev_pm_arm_wake_irq(ws->wakeirq);
 340         }
 341         rcu_read_unlock();
 342 }
 343
 344 /**
 345  * device_wakeup_disarm_wake_irqs(void)
 346  *
 347  * Itereates over the list of device wakeirqs to disarm them.
 348  */
 349 void device_wakeup_disarm_wake_irqs(void)
 350 {
 351         struct wakeup_source *ws;
 352
 353         rcu_read_lock();
 354         list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
 355                 if (ws->wakeirq)
 356                         dev_pm_disarm_wake_irq(ws->wakeirq);
 357         }
 358         rcu_read_unlock();
 359 }
 360
 361 /**
 362  * device_wakeup_detach - Detach a device's wakeup source object from it.
 363  * @dev: Device to detach the wakeup source object from.
 364  *
 365  * After it returns, @dev will not be treated as a wakeup device any more.
 366  */
 367 static struct wakeup_source *device_wakeup_detach(struct device *dev)
 368 {
 369         struct wakeup_source *ws;
 370
 371         spin_lock_irq(&dev->power.lock);
 372         ws = dev->power.wakeup;
 373         dev->power.wakeup = NULL;
 374         spin_unlock_irq(&dev->power.lock);
 375         return ws;
 376 }
 377
 378 /**
 379  * device_wakeup_disable - Do not regard a device as a wakeup source any more.
 380  * @dev: Device to handle.
 381  *
 382  * Detach the @dev's wakeup source object from it, unregister this wakeup source
 383  * object and destroy it.
 384  */
 385 int device_wakeup_disable(struct device *dev)
 386 {
 387         struct wakeup_source *ws;
 388
 389         if (!dev || !dev->power.can_wakeup)
 390                 return -EINVAL;
 391
 392         ws = device_wakeup_detach(dev);
 393         if (ws)
 394                 wakeup_source_unregister(ws);
 395
 396         return 0;
 397 }
 398 EXPORT_SYMBOL_GPL(device_wakeup_disable);
 399
 400 /**
 401  * device_set_wakeup_capable - Set/reset device wakeup capability flag.
 402  * @dev: Device to handle.
 403  * @capable: Whether or not @dev is capable of waking up the system from sleep.
 404  *
 405  * If @capable is set, set the @dev's power.can_wakeup flag and add its
 406  * wakeup-related attributes to sysfs.  Otherwise, unset the @dev's
 407  * power.can_wakeup flag and remove its wakeup-related attributes from sysfs.
 408  *
 409  * This function may sleep and it can't be called from any context where
 410  * sleeping is not allowed.
 411  */
 412 void device_set_wakeup_capable(struct device *dev, bool capable)
 413 {
 414         if (!!dev->power.can_wakeup == !!capable)
 415                 return;
 416
 417         if (device_is_registered(dev) && !list_empty(&dev->power.entry)) {
 418                 if (capable) {
 419                         if (wakeup_sysfs_add(dev))
 420                                 return;
 421                 } else {
 422                         wakeup_sysfs_remove(dev);
 423                 }
 424         }
 425         dev->power.can_wakeup = capable;
 426 }
 427 EXPORT_SYMBOL_GPL(device_set_wakeup_capable);
 428
 429 /**
 430  * device_init_wakeup - Device wakeup initialization.
 431  * @dev: Device to handle.
 432  * @enable: Whether or not to enable @dev as a wakeup device.
 433  *
 434  * By default, most devices should leave wakeup disabled.  The exceptions are
 435  * devices that everyone expects to be wakeup sources: keyboards, power buttons,
 436  * possibly network interfaces, etc.  Also, devices that don't generate their
 437  * own wakeup requests but merely forward requests from one bus to another
 438  * (like PCI bridges) should have wakeup enabled by default.
 439  */
 440 int device_init_wakeup(struct device *dev, bool enable)
 441 {
 442         int ret = 0;
 443
 444         if (!dev)
 445                 return -EINVAL;
 446
 447         if (enable) {
 448                 device_set_wakeup_capable(dev, true);
 449                 ret = device_wakeup_enable(dev);
 450         } else {
 451                 if (dev->power.can_wakeup)
 452                         device_wakeup_disable(dev);
 453
 454                 device_set_wakeup_capable(dev, false);
 455         }
 456
 457         return ret;
 458 }
 459 EXPORT_SYMBOL_GPL(device_init_wakeup);
 460
 461 /**
 462  * device_set_wakeup_enable - Enable or disable a device to wake up the system.
 463  * @dev: Device to handle.
 464  */
 465 int device_set_wakeup_enable(struct device *dev, bool enable)
 466 {
 467         if (!dev || !dev->power.can_wakeup)
 468                 return -EINVAL;
 469
 470         return enable ? device_wakeup_enable(dev) : device_wakeup_disable(dev);
 471 }
 472 EXPORT_SYMBOL_GPL(device_set_wakeup_enable);
 473
 474 /**
 475  * wakeup_source_not_registered - validate the given wakeup source.
 476  * @ws: Wakeup source to be validated.
 477  */
 478 static bool wakeup_source_not_registered(struct wakeup_source *ws)
 479 {
 480         /*
 481          * Use timer struct to check if the given source is initialized
 482          * by wakeup_source_add.
 483          */
 484         return ws->timer.function != pm_wakeup_timer_fn ||
 485                    ws->timer.data != (unsigned long)ws;
 486 }
 487
 488 /*
 489  * The functions below use the observation that each wakeup event starts a
 490  * period in which the system should not be suspended.  The moment this period
 491  * will end depends on how the wakeup event is going to be processed after being
 492  * detected and all of the possible cases can be divided into two distinct
 493  * groups.
 494  *
 495  * First, a wakeup event may be detected by the same functional unit that will
 496  * carry out the entire processing of it and possibly will pass it to user space
 497  * for further processing.  In that case the functional unit that has detected
 498  * the event may later "close" the "no suspend" period associated with it
 499  * directly as soon as it has been dealt with.  The pair of pm_stay_awake() and
 500  * pm_relax(), balanced with each other, is supposed to be used in such
 501  * situations.
 502  *
 503  * Second, a wakeup event may be detected by one functional unit and processed
 504  * by another one.  In that case the unit that has detected it cannot really
 505  * "close" the "no suspend" period associated with it, unless it knows in
 506  * advance what's going to happen to the event during processing.  This
 507  * knowledge, however, may not be available to it, so it can simply specify time
 508  * to wait before the system can be suspended and pass it as the second
 509  * argument of pm_wakeup_event().
 510  *
 511  * It is valid to call pm_relax() after pm_wakeup_event(), in which case the
 512  * "no suspend" period will be ended either by the pm_relax(), or by the timer
 513  * function executed when the timer expires, whichever comes first.
 514  */
 515
 516 /**
 517  * wakup_source_activate - Mark given wakeup source as active.
 518  * @ws: Wakeup source to handle.
 519  *
 520  * Update the @ws' statistics and, if @ws has just been activated, notify the PM
 521  * core of the event by incrementing the counter of of wakeup events being
 522  * processed.
 523  */
 524 static void wakeup_source_activate(struct wakeup_source *ws)
 525 {
 526         unsigned int cec;
 527
 528         if (WARN_ONCE(wakeup_source_not_registered(ws),
 529                         "unregistered wakeup source\n"))
 530                 return;
 531
 532         /*
 533          * active wakeup source should bring the system
 534          * out of PM_SUSPEND_FREEZE state
 535          */
 536         freeze_wake();
 537
 538         ws->active = true;
 539         ws->active_count++;
 540         ws->last_time = ktime_get();
 541         if (ws->autosleep_enabled)
 542                 ws->start_prevent_time = ws->last_time;
 543
 544         /* Increment the counter of events in progress. */
 545         cec = atomic_inc_return(&combined_event_count);
 546
 547         trace_wakeup_source_activate(ws->name, cec);
 548 }
 549
 550 /**
 551  * wakeup_source_report_event - Report wakeup event using the given source.
 552  * @ws: Wakeup source to report the event for.
 553  */
 554 static void wakeup_source_report_event(struct wakeup_source *ws)
 555 {
 556         ws->event_count++;
 557         /* This is racy, but the counter is approximate anyway. */
 558         if (events_check_enabled)
 559                 ws->wakeup_count++;
 560
 561         if (!ws->active)
 562                 wakeup_source_activate(ws);
 563 }
 564
 565 /**
 566  * __pm_stay_awake - Notify the PM core of a wakeup event.
 567  * @ws: Wakeup source object associated with the source of the event.
 568  *
 569  * It is safe to call this function from interrupt context.
 570  */
 571 void __pm_stay_awake(struct wakeup_source *ws)
 572 {
 573         unsigned long flags;
 574
 575         if (!ws)
 576                 return;
 577
 578         spin_lock_irqsave(&ws->lock, flags);
 579
 580         wakeup_source_report_event(ws);
 581         del_timer(&ws->timer);
 582         ws->timer_expires = 0;
 583
 584         spin_unlock_irqrestore(&ws->lock, flags);
 585 }
 586 EXPORT_SYMBOL_GPL(__pm_stay_awake);
 587
 588 /**
 589  * pm_stay_awake - Notify the PM core that a wakeup event is being processed.
 590  * @dev: Device the wakeup event is related to.
 591  *
 592  * Notify the PM core of a wakeup event (signaled by @dev) by calling
 593  * __pm_stay_awake for the @dev's wakeup source object.
 594  *
 595  * Call this function after detecting of a wakeup event if pm_relax() is going
 596  * to be called directly after processing the event (and possibly passing it to
 597  * user space for further processing).
 598  */
 599 void pm_stay_awake(struct device *dev)
 600 {
 601         unsigned long flags;
 602
 603         if (!dev)
 604                 return;
 605
 606         spin_lock_irqsave(&dev->power.lock, flags);
 607         __pm_stay_awake(dev->power.wakeup);
 608         spin_unlock_irqrestore(&dev->power.lock, flags);
 609 }
 610 EXPORT_SYMBOL_GPL(pm_stay_awake);
 611
 612 #ifdef CONFIG_PM_AUTOSLEEP
 613 static void update_prevent_sleep_time(struct wakeup_source *ws, ktime_t now)
 614 {
 615         ktime_t delta = ktime_sub(now, ws->start_prevent_time);
 616         ws->prevent_sleep_time = ktime_add(ws->prevent_sleep_time, delta);
 617 }
 618 #else
 619 static inline void update_prevent_sleep_time(struct wakeup_source *ws,
 620                                              ktime_t now) {}
 621 #endif
 622
 623 /**
 624  * wakup_source_deactivate - Mark given wakeup source as inactive.
 625  * @ws: Wakeup source to handle.
 626  *
 627  * Update the @ws' statistics and notify the PM core that the wakeup source has
 628  * become inactive by decrementing the counter of wakeup events being processed
 629  * and incrementing the counter of registered wakeup events.
 630  */
 631 static void wakeup_source_deactivate(struct wakeup_source *ws)
 632 {
 633         unsigned int cnt, inpr, cec;
 634         ktime_t duration;
 635         ktime_t now;
 636
 637         ws->relax_count++;
 638         /*
 639          * __pm_relax() may be called directly or from a timer function.
 640          * If it is called directly right after the timer function has been
 641          * started, but before the timer function calls __pm_relax(), it is
 642          * possible that __pm_stay_awake() will be called in the meantime and
 643          * will set ws->active.  Then, ws->active may be cleared immediately
 644          * by the __pm_relax() called from the timer function, but in such a
 645          * case ws->relax_count will be different from ws->active_count.
 646          */
 647         if (ws->relax_count != ws->active_count) {
 648                 ws->relax_count--;
 649                 return;
 650         }
 651
 652         ws->active = false;
 653
 654         now = ktime_get();
 655         duration = ktime_sub(now, ws->last_time);
 656         ws->total_time = ktime_add(ws->total_time, duration);
 657         if (ktime_to_ns(duration) > ktime_to_ns(ws->max_time))
 658                 ws->max_time = duration;
 659
 660         ws->last_time = now;
 661         del_timer(&ws->timer);
 662         ws->timer_expires = 0;
 663
 664         if (ws->autosleep_enabled)
 665                 update_prevent_sleep_time(ws, now);
 666
 667         /*
 668          * Increment the counter of registered wakeup events and decrement the
 669          * couter of wakeup events in progress simultaneously.
 670          */
 671         cec = atomic_add_return(MAX_IN_PROGRESS, &combined_event_count);
 672         trace_wakeup_source_deactivate(ws->name, cec);
 673
 674         split_counters(&cnt, &inpr);
 675         if (!inpr && waitqueue_active(&wakeup_count_wait_queue))
 676                 wake_up(&wakeup_count_wait_queue);
 677 }
 678
 679 /**
 680  * __pm_relax - Notify the PM core that processing of a wakeup event has ended.
 681  * @ws: Wakeup source object associated with the source of the event.
 682  *
 683  * Call this function for wakeup events whose processing started with calling
 684  * __pm_stay_awake().
 685  *
 686  * It is safe to call it from interrupt context.
 687  */
 688 void __pm_relax(struct wakeup_source *ws)
 689 {
 690         unsigned long flags;
 691
 692         if (!ws)
 693                 return;
 694
 695         spin_lock_irqsave(&ws->lock, flags);
 696         if (ws->active)
 697                 wakeup_source_deactivate(ws);
 698         spin_unlock_irqrestore(&ws->lock, flags);
 699 }
 700 EXPORT_SYMBOL_GPL(__pm_relax);
 701
 702 /**
 703  * pm_relax - Notify the PM core that processing of a wakeup event has ended.
 704  * @dev: Device that signaled the event.
 705  *
 706  * Execute __pm_relax() for the @dev's wakeup source object.
 707  */
 708 void pm_relax(struct device *dev)
 709 {
 710         unsigned long flags;
 711
 712         if (!dev)
 713                 return;
 714
 715         spin_lock_irqsave(&dev->power.lock, flags);
 716         __pm_relax(dev->power.wakeup);
 717         spin_unlock_irqrestore(&dev->power.lock, flags);
 718 }
 719 EXPORT_SYMBOL_GPL(pm_relax);
 720
 721 /**
 722  * pm_wakeup_timer_fn - Delayed finalization of a wakeup event.
 723  * @data: Address of the wakeup source object associated with the event source.
 724  *
 725  * Call wakeup_source_deactivate() for the wakeup source whose address is stored
 726  * in @data if it is currently active and its timer has not been canceled and
 727  * the expiration time of the timer is not in future.
 728  */
 729 static void pm_wakeup_timer_fn(unsigned long data)
 730 {
 731         struct wakeup_source *ws = (struct wakeup_source *)data;
 732         unsigned long flags;
 733
 734         spin_lock_irqsave(&ws->lock, flags);
 735
 736         if (ws->active && ws->timer_expires
 737             && time_after_eq(jiffies, ws->timer_expires)) {
 738                 wakeup_source_deactivate(ws);
 739                 ws->expire_count++;
 740         }
 741
 742         spin_unlock_irqrestore(&ws->lock, flags);
 743 }
 744
 745 /**
 746  * __pm_wakeup_event - Notify the PM core of a wakeup event.
 747  * @ws: Wakeup source object associated with the event source.
 748  * @msec: Anticipated event processing time (in milliseconds).
 749  *
 750  * Notify the PM core of a wakeup event whose source is @ws that will take
 751  * approximately @msec milliseconds to be processed by the kernel.  If @ws is
 752  * not active, activate it.  If @msec is nonzero, set up the @ws' timer to
 753  * execute pm_wakeup_timer_fn() in future.
 754  *
 755  * It is safe to call this function from interrupt context.
 756  */
 757 void __pm_wakeup_event(struct wakeup_source *ws, unsigned int msec)
 758 {
 759         unsigned long flags;
 760         unsigned long expires;
 761
 762         if (!ws)
 763                 return;
 764
 765         spin_lock_irqsave(&ws->lock, flags);
 766
 767         wakeup_source_report_event(ws);
 768
 769         if (!msec) {
 770                 wakeup_source_deactivate(ws);
 771                 goto unlock;
 772         }
 773
 774         expires = jiffies + msecs_to_jiffies(msec);
 775         if (!expires)
 776                 expires = 1;
 777
 778         if (!ws->timer_expires || time_after(expires, ws->timer_expires)) {
 779                 mod_timer(&ws->timer, expires);
 780                 ws->timer_expires = expires;
 781         }
 782
 783  unlock:
 784         spin_unlock_irqrestore(&ws->lock, flags);
 785 }
 786 EXPORT_SYMBOL_GPL(__pm_wakeup_event);
 787
 788
 789 /**
 790  * pm_wakeup_event - Notify the PM core of a wakeup event.
 791  * @dev: Device the wakeup event is related to.
 792  * @msec: Anticipated event processing time (in milliseconds).
 793  *
 794  * Call __pm_wakeup_event() for the @dev's wakeup source object.
 795  */
 796 void pm_wakeup_event(struct device *dev, unsigned int msec)
 797 {
 798         unsigned long flags;
 799
 800         if (!dev)
 801                 return;
 802
 803         spin_lock_irqsave(&dev->power.lock, flags);
 804         __pm_wakeup_event(dev->power.wakeup, msec);
 805         spin_unlock_irqrestore(&dev->power.lock, flags);
 806 }
 807 EXPORT_SYMBOL_GPL(pm_wakeup_event);
 808
 809 void pm_print_active_wakeup_sources(void)
 810 {
 811         struct wakeup_source *ws;
 812         int active = 0;
 813         struct wakeup_source *last_activity_ws = NULL;
 814
 815         rcu_read_lock();
 816         list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
 817                 if (ws->active) {
 818                         pr_info("active wakeup source: %s\n", ws->name);
 819                         active = 1;
 820                 } else if (!active &&
 821                            (!last_activity_ws ||
 822                             ktime_to_ns(ws->last_time) >
 823                             ktime_to_ns(last_activity_ws->last_time))) {
 824                         last_activity_ws = ws;
 825                 }
 826         }
 827
 828         if (!active && last_activity_ws)
 829                 pr_info("last active wakeup source: %s\n",
 830                         last_activity_ws->name);
 831         rcu_read_unlock();
 832 }
 833 EXPORT_SYMBOL_GPL(pm_print_active_wakeup_sources);
 834
 835 /**
 836  * pm_wakeup_pending - Check if power transition in progress should be aborted.
 837  *
 838  * Compare the current number of registered wakeup events with its preserved
 839  * value from the past and return true if new wakeup events have been registered
 840  * since the old value was stored.  Also return true if the current number of
 841  * wakeup events being processed is different from zero.
 842  */
 843 bool pm_wakeup_pending(void)
 844 {
 845         unsigned long flags;
 846         bool ret = false;
 847
 848         spin_lock_irqsave(&events_lock, flags);
 849         if (events_check_enabled) {
 850                 unsigned int cnt, inpr;
 851
 852                 split_counters(&cnt, &inpr);
 853                 ret = (cnt != saved_count || inpr > 0);
 854                 events_check_enabled = !ret;
 855         }
 856         spin_unlock_irqrestore(&events_lock, flags);
 857
 858         if (ret) {
 859                 pr_info("PM: Wakeup pending, aborting suspend\n");
 860                 pm_print_active_wakeup_sources();
 861         }
 862
 863         return ret || pm_abort_suspend;
 864 }
 865
 866 void pm_system_wakeup(void)
 867 {
 868         pm_abort_suspend = true;
 869         freeze_wake();
 870 }
 871 EXPORT_SYMBOL_GPL(pm_system_wakeup);
 872
 873 void pm_wakeup_clear(void)
 874 {
 875         pm_abort_suspend = false;
 876         pm_wakeup_irq = 0;
 877 }
 878
 879 void pm_system_irq_wakeup(unsigned int irq_number)
 880 {
 881         if (pm_wakeup_irq == 0) {
 882                 pm_wakeup_irq = irq_number;
 883                 pm_system_wakeup();
 884         }
 885 }
 886
 887 /**
 888  * pm_get_wakeup_count - Read the number of registered wakeup events.
 889  * @count: Address to store the value at.
 890  * @block: Whether or not to block.
 891  *
 892  * Store the number of registered wakeup events at the address in @count.  If
 893  * @block is set, block until the current number of wakeup events being
 894  * processed is zero.
 895  *
 896  * Return 'false' if the current number of wakeup events being processed is
 897  * nonzero.  Otherwise return 'true'.
 898  */
 899 bool pm_get_wakeup_count(unsigned int *count, bool block)
 900 {
 901         unsigned int cnt, inpr;
 902
 903         if (block) {
 904                 DEFINE_WAIT(wait);
 905
 906                 for (;;) {
 907                         prepare_to_wait(&wakeup_count_wait_queue, &wait,
 908                                         TASK_INTERRUPTIBLE);
 909                         split_counters(&cnt, &inpr);
 910                         if (inpr == 0 || signal_pending(current))
 911                                 break;
 912
 913                         schedule();
 914                 }
 915                 finish_wait(&wakeup_count_wait_queue, &wait);
 916         }
 917
 918         split_counters(&cnt, &inpr);
 919         *count = cnt;
 920         return !inpr;
 921 }
 922
 923 /**
 924  * pm_save_wakeup_count - Save the current number of registered wakeup events.
 925  * @count: Value to compare with the current number of registered wakeup events.
 926  *
 927  * If @count is equal to the current number of registered wakeup events and the
 928  * current number of wakeup events being processed is zero, store @count as the
 929  * old number of registered wakeup events for pm_check_wakeup_events(), enable
 930  * wakeup events detection and return 'true'.  Otherwise disable wakeup events
 931  * detection and return 'false'.
 932  */
 933 bool pm_save_wakeup_count(unsigned int count)
 934 {
 935         unsigned int cnt, inpr;
 936         unsigned long flags;
 937
 938         events_check_enabled = false;
 939         spin_lock_irqsave(&events_lock, flags);
 940         split_counters(&cnt, &inpr);
 941         if (cnt == count && inpr == 0) {
 942                 saved_count = count;
 943                 events_check_enabled = true;
 944         }
 945         spin_unlock_irqrestore(&events_lock, flags);
 946         return events_check_enabled;
 947 }
 948
 949 #ifdef CONFIG_PM_AUTOSLEEP
 950 /**
 951  * pm_wakep_autosleep_enabled - Modify autosleep_enabled for all wakeup sources.
 952  * @enabled: Whether to set or to clear the autosleep_enabled flags.
 953  */
 954 void pm_wakep_autosleep_enabled(bool set)
 955 {
 956         struct wakeup_source *ws;
 957         ktime_t now = ktime_get();
 958
 959         rcu_read_lock();
 960         list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
 961                 spin_lock_irq(&ws->lock);
 962                 if (ws->autosleep_enabled != set) {
 963                         ws->autosleep_enabled = set;
 964                         if (ws->active) {
 965                                 if (set)
 966                                         ws->start_prevent_time = now;
 967                                 else
 968                                         update_prevent_sleep_time(ws, now);
 969                         }
 970                 }
 971                 spin_unlock_irq(&ws->lock);
 972         }
 973         rcu_read_unlock();
 974 }
 975 #endif /* CONFIG_PM_AUTOSLEEP */
 976
 977 static struct dentry *wakeup_sources_stats_dentry;
 978
 979 /**
 980  * print_wakeup_source_stats - Print wakeup source statistics information.
 981  * @m: seq_file to print the statistics into.
 982  * @ws: Wakeup source object to print the statistics for.
 983  */
 984 static int print_wakeup_source_stats(struct seq_file *m,
 985                                      struct wakeup_source *ws)
 986 {
 987         unsigned long flags;
 988         ktime_t total_time;
 989         ktime_t max_time;
 990         unsigned long active_count;
 991         ktime_t active_time;
 992         ktime_t prevent_sleep_time;
 993
 994         spin_lock_irqsave(&ws->lock, flags);
 995
 996         total_time = ws->total_time;
 997         max_time = ws->max_time;
 998         prevent_sleep_time = ws->prevent_sleep_time;
 999         active_count = ws->active_count;
1000         if (ws->active) {
1001                 ktime_t now = ktime_get();
1002
1003                 active_time = ktime_sub(now, ws->last_time);
1004                 total_time = ktime_add(total_time, active_time);
1005                 if (active_time.tv64 > max_time.tv64)
1006                         max_time = active_time;
1007
1008                 if (ws->autosleep_enabled)
1009                         prevent_sleep_time = ktime_add(prevent_sleep_time,
1010                                 ktime_sub(now, ws->start_prevent_time));
1011         } else {
1012                 active_time = ktime_set(0, 0);
1013         }
1014
1015         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",
1016                    ws->name, active_count, ws->event_count,
1017                    ws->wakeup_count, ws->expire_count,
1018                    ktime_to_ms(active_time), ktime_to_ms(total_time),
1019                    ktime_to_ms(max_time), ktime_to_ms(ws->last_time),
1020                    ktime_to_ms(prevent_sleep_time));
1021
1022         spin_unlock_irqrestore(&ws->lock, flags);
1023
1024         return 0;
1025 }
1026
1027 /**
1028  * wakeup_sources_stats_show - Print wakeup sources statistics information.
1029  * @m: seq_file to print the statistics into.
1030  */
1031 static int wakeup_sources_stats_show(struct seq_file *m, void *unused)
1032 {
1033         struct wakeup_source *ws;
1034
1035         seq_puts(m, "name\t\tactive_count\tevent_count\twakeup_count\t"
1036                 "expire_count\tactive_since\ttotal_time\tmax_time\t"
1037                 "last_change\tprevent_suspend_time\n");
1038
1039         rcu_read_lock();
1040         list_for_each_entry_rcu(ws, &wakeup_sources, entry)
1041                 print_wakeup_source_stats(m, ws);
1042         rcu_read_unlock();
1043
1044         print_wakeup_source_stats(m, &deleted_ws);
1045
1046         return 0;
1047 }
1048
1049 static int wakeup_sources_stats_open(struct inode *inode, struct file *file)
1050 {
1051         return single_open(file, wakeup_sources_stats_show, NULL);
1052 }
1053
1054 static const struct file_operations wakeup_sources_stats_fops = {
1055         .owner = THIS_MODULE,
1056         .open = wakeup_sources_stats_open,
1057         .read = seq_read,
1058         .llseek = seq_lseek,
1059         .release = single_release,
1060 };
1061
1062 static int __init wakeup_sources_debugfs_init(void)
1063 {
1064         wakeup_sources_stats_dentry = debugfs_create_file("wakeup_sources",
1065                         S_IRUGO, NULL, NULL, &wakeup_sources_stats_fops);
1066         return 0;
1067 }
1068
1069 postcore_initcall(wakeup_sources_debugfs_init);