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 <linux/types.h>
  19 #include <trace/events/power.h>
  20
  21 #include "power.h"
  22
  23 /*
  24  * If set, the suspend/hibernate code will abort transitions to a sleep state
  25  * if wakeup events are registered during or immediately before the transition.
  26  */
  27 bool events_check_enabled __read_mostly;
  28
  29 /* First wakeup IRQ seen by the kernel in the last cycle. */
  30 unsigned int pm_wakeup_irq __read_mostly;
  31
  32 /* If set and the system is suspending, terminate the suspend. */
  33 static bool pm_abort_suspend __read_mostly;
  34
  35 /*
  36  * Combined counters of registered wakeup events and wakeup events in progress.
  37  * They need to be modified together atomically, so it's better to use one
  38  * atomic variable to hold them both.
  39  */
  40 static atomic_t combined_event_count = ATOMIC_INIT(0);
  41
  42 #define IN_PROGRESS_BITS        (sizeof(int) * 4)
  43 #define MAX_IN_PROGRESS         ((1 << IN_PROGRESS_BITS) - 1)
  44
  45 static void split_counters(unsigned int *cnt, unsigned int *inpr)
  46 {
  47         unsigned int comb = atomic_read(&combined_event_count);
  48
  49         *cnt = (comb >> IN_PROGRESS_BITS);
  50         *inpr = comb & MAX_IN_PROGRESS;
  51 }
  52
  53 /* A preserved old value of the events counter. */
  54 static unsigned int saved_count;
  55
  56 static DEFINE_SPINLOCK(events_lock);
  57
  58 static void pm_wakeup_timer_fn(unsigned long data);
  59
  60 static LIST_HEAD(wakeup_sources);
  61
  62 static DECLARE_WAIT_QUEUE_HEAD(wakeup_count_wait_queue);
  63
  64 static struct wakeup_source deleted_ws = {
  65         .name = "deleted",
  66         .lock =  __SPIN_LOCK_UNLOCKED(deleted_ws.lock),
  67 };
  68
  69 /**
  70  * wakeup_source_prepare - Prepare a new wakeup source for initialization.
  71  * @ws: Wakeup source to prepare.
  72  * @name: Pointer to the name of the new wakeup source.
  73  *
  74  * Callers must ensure that the @name string won't be freed when @ws is still in
  75  * use.
  76  */
  77 void wakeup_source_prepare(struct wakeup_source *ws, const char *name)
  78 {
  79         if (ws) {
  80                 memset(ws, 0, sizeof(*ws));
  81                 ws->name = name;
  82         }
  83 }
  84 EXPORT_SYMBOL_GPL(wakeup_source_prepare);
  85
  86 /**
  87  * wakeup_source_create - Create a struct wakeup_source object.
  88  * @name: Name of the new wakeup source.
  89  */
  90 struct wakeup_source *wakeup_source_create(const char *name)
  91 {
  92         struct wakeup_source *ws;
  93
  94         ws = kmalloc(sizeof(*ws), GFP_KERNEL);
  95         if (!ws)
  96                 return NULL;
  97
  98         wakeup_source_prepare(ws, name ? kstrdup_const(name, GFP_KERNEL) : NULL);
  99         return ws;
 100 }
 101 EXPORT_SYMBOL_GPL(wakeup_source_create);
 102
 103 /**
 104  * wakeup_source_drop - Prepare a struct wakeup_source object for destruction.
 105  * @ws: Wakeup source to prepare for destruction.
 106  *
 107  * Callers must ensure that __pm_stay_awake() or __pm_wakeup_event() will never
 108  * be run in parallel with this function for the same wakeup source object.
 109  */
 110 void wakeup_source_drop(struct wakeup_source *ws)
 111 {
 112         if (!ws)
 113                 return;
 114
 115         del_timer_sync(&ws->timer);
 116         __pm_relax(ws);
 117 }
 118 EXPORT_SYMBOL_GPL(wakeup_source_drop);
 119
 120 /*
 121  * Record wakeup_source statistics being deleted into a dummy wakeup_source.
 122  */
 123 static void wakeup_source_record(struct wakeup_source *ws)
 124 {
 125         unsigned long flags;
 126
 127         spin_lock_irqsave(&deleted_ws.lock, flags);
 128
 129         if (ws->event_count) {
 130                 deleted_ws.total_time =
 131                         ktime_add(deleted_ws.total_time, ws->total_time);
 132                 deleted_ws.prevent_sleep_time =
 133                         ktime_add(deleted_ws.prevent_sleep_time,
 134                                   ws->prevent_sleep_time);
 135                 deleted_ws.max_time =
 136                         ktime_compare(deleted_ws.max_time, ws->max_time) > 0 ?
 137                                 deleted_ws.max_time : ws->max_time;
 138                 deleted_ws.event_count += ws->event_count;
 139                 deleted_ws.active_count += ws->active_count;
 140                 deleted_ws.relax_count += ws->relax_count;
 141                 deleted_ws.expire_count += ws->expire_count;
 142                 deleted_ws.wakeup_count += ws->wakeup_count;
 143         }
 144
 145         spin_unlock_irqrestore(&deleted_ws.lock, flags);
 146 }
 147
 148 /**
 149  * wakeup_source_destroy - Destroy a struct wakeup_source object.
 150  * @ws: Wakeup source to destroy.
 151  *
 152  * Use only for wakeup source objects created with wakeup_source_create().
 153  */
 154 void wakeup_source_destroy(struct wakeup_source *ws)
 155 {
 156         if (!ws)
 157                 return;
 158
 159         wakeup_source_drop(ws);
 160         wakeup_source_record(ws);
 161         kfree_const(ws->name);
 162         kfree(ws);
 163 }
 164 EXPORT_SYMBOL_GPL(wakeup_source_destroy);
 165
 166 /**
 167  * wakeup_source_add - Add given object to the list of wakeup sources.
 168  * @ws: Wakeup source object to add to the list.
 169  */
 170 void wakeup_source_add(struct wakeup_source *ws)
 171 {
 172         unsigned long flags;
 173
 174         if (WARN_ON(!ws))
 175                 return;
 176
 177         spin_lock_init(&ws->lock);
 178         setup_timer(&ws->timer, pm_wakeup_timer_fn, (unsigned long)ws);
 179         ws->active = false;
 180         ws->last_time = ktime_get();
 181
 182         spin_lock_irqsave(&events_lock, flags);
 183         list_add_rcu(&ws->entry, &wakeup_sources);
 184         spin_unlock_irqrestore(&events_lock, flags);
 185 }
 186 EXPORT_SYMBOL_GPL(wakeup_source_add);
 187
 188 /**
 189  * wakeup_source_remove - Remove given object from the wakeup sources list.
 190  * @ws: Wakeup source object to remove from the list.
 191  */
 192 void wakeup_source_remove(struct wakeup_source *ws)
 193 {
 194         unsigned long flags;
 195
 196         if (WARN_ON(!ws))
 197                 return;
 198
 199         spin_lock_irqsave(&events_lock, flags);
 200         list_del_rcu(&ws->entry);
 201         spin_unlock_irqrestore(&events_lock, flags);
 202         synchronize_rcu();
 203 }
 204 EXPORT_SYMBOL_GPL(wakeup_source_remove);
 205
 206 /**
 207  * wakeup_source_register - Create wakeup source and add it to the list.
 208  * @name: Name of the wakeup source to register.
 209  */
 210 struct wakeup_source *wakeup_source_register(const char *name)
 211 {
 212         struct wakeup_source *ws;
 213
 214         ws = wakeup_source_create(name);
 215         if (ws)
 216                 wakeup_source_add(ws);
 217
 218         return ws;
 219 }
 220 EXPORT_SYMBOL_GPL(wakeup_source_register);
 221
 222 /**
 223  * wakeup_source_unregister - Remove wakeup source from the list and remove it.
 224  * @ws: Wakeup source object to unregister.
 225  */
 226 void wakeup_source_unregister(struct wakeup_source *ws)
 227 {
 228         if (ws) {
 229                 wakeup_source_remove(ws);
 230                 wakeup_source_destroy(ws);
 231         }
 232 }
 233 EXPORT_SYMBOL_GPL(wakeup_source_unregister);
 234
 235 /**
 236  * device_wakeup_attach - Attach a wakeup source object to a device object.
 237  * @dev: Device to handle.
 238  * @ws: Wakeup source object to attach to @dev.
 239  *
 240  * This causes @dev to be treated as a wakeup device.
 241  */
 242 static int device_wakeup_attach(struct device *dev, struct wakeup_source *ws)
 243 {
 244         spin_lock_irq(&dev->power.lock);
 245         if (dev->power.wakeup) {
 246                 spin_unlock_irq(&dev->power.lock);
 247                 return -EEXIST;
 248         }
 249         dev->power.wakeup = ws;
 250         spin_unlock_irq(&dev->power.lock);
 251         return 0;
 252 }
 253
 254 /**
 255  * device_wakeup_enable - Enable given device to be a wakeup source.
 256  * @dev: Device to handle.
 257  *
 258  * Create a wakeup source object, register it and attach it to @dev.
 259  */
 260 int device_wakeup_enable(struct device *dev)
 261 {
 262         struct wakeup_source *ws;
 263         int ret;
 264
 265         if (!dev || !dev->power.can_wakeup)
 266                 return -EINVAL;
 267
 268         ws = wakeup_source_register(dev_name(dev));
 269         if (!ws)
 270                 return -ENOMEM;
 271
 272         ret = device_wakeup_attach(dev, ws);
 273         if (ret)
 274                 wakeup_source_unregister(ws);
 275
 276         return ret;
 277 }
 278 EXPORT_SYMBOL_GPL(device_wakeup_enable);
 279
 280 /**
 281  * device_wakeup_attach_irq - Attach a wakeirq to a wakeup source
 282  * @dev: Device to handle
 283  * @wakeirq: Device specific wakeirq entry
 284  *
 285  * Attach a device wakeirq to the wakeup source so the device
 286  * wake IRQ can be configured automatically for suspend and
 287  * resume.
 288  *
 289  * Call under the device's power.lock lock.
 290  */
 291 int device_wakeup_attach_irq(struct device *dev,
 292                              struct wake_irq *wakeirq)
 293 {
 294         struct wakeup_source *ws;
 295
 296         ws = dev->power.wakeup;
 297         if (!ws) {
 298                 dev_err(dev, "forgot to call call device_init_wakeup?\n");
 299                 return -EINVAL;
 300         }
 301
 302         if (ws->wakeirq)
 303                 return -EEXIST;
 304
 305         ws->wakeirq = wakeirq;
 306         return 0;
 307 }
 308
 309 /**
 310  * device_wakeup_detach_irq - Detach a wakeirq from a wakeup source
 311  * @dev: Device to handle
 312  *
 313  * Removes a device wakeirq from the wakeup source.
 314  *
 315  * Call under the device's power.lock lock.
 316  */
 317 void device_wakeup_detach_irq(struct device *dev)
 318 {
 319         struct wakeup_source *ws;
 320
 321         ws = dev->power.wakeup;
 322         if (ws)
 323                 ws->wakeirq = NULL;
 324 }
 325
 326 /**
 327  * device_wakeup_arm_wake_irqs(void)
 328  *
 329  * Itereates over the list of device wakeirqs to arm them.
 330  */
 331 void device_wakeup_arm_wake_irqs(void)
 332 {
 333         struct wakeup_source *ws;
 334
 335         rcu_read_lock();
 336         list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
 337                 if (ws->wakeirq)
 338                         dev_pm_arm_wake_irq(ws->wakeirq);
 339         }
 340         rcu_read_unlock();
 341 }
 342
 343 /**
 344  * device_wakeup_disarm_wake_irqs(void)
 345  *
 346  * Itereates over the list of device wakeirqs to disarm them.
 347  */
 348 void device_wakeup_disarm_wake_irqs(void)
 349 {
 350         struct wakeup_source *ws;
 351
 352         rcu_read_lock();
 353         list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
 354                 if (ws->wakeirq)
 355                         dev_pm_disarm_wake_irq(ws->wakeirq);
 356         }
 357         rcu_read_unlock();
 358 }
 359
 360 /**
 361  * device_wakeup_detach - Detach a device's wakeup source object from it.
 362  * @dev: Device to detach the wakeup source object from.
 363  *
 364  * After it returns, @dev will not be treated as a wakeup device any more.
 365  */
 366 static struct wakeup_source *device_wakeup_detach(struct device *dev)
 367 {
 368         struct wakeup_source *ws;
 369
 370         spin_lock_irq(&dev->power.lock);
 371         ws = dev->power.wakeup;
 372         dev->power.wakeup = NULL;
 373         spin_unlock_irq(&dev->power.lock);
 374         return ws;
 375 }
 376
 377 /**
 378  * device_wakeup_disable - Do not regard a device as a wakeup source any more.
 379  * @dev: Device to handle.
 380  *
 381  * Detach the @dev's wakeup source object from it, unregister this wakeup source
 382  * object and destroy it.
 383  */
 384 int device_wakeup_disable(struct device *dev)
 385 {
 386         struct wakeup_source *ws;
 387
 388         if (!dev || !dev->power.can_wakeup)
 389                 return -EINVAL;
 390
 391         ws = device_wakeup_detach(dev);
 392         if (ws)
 393                 wakeup_source_unregister(ws);
 394
 395         return 0;
 396 }
 397 EXPORT_SYMBOL_GPL(device_wakeup_disable);
 398
 399 /**
 400  * device_set_wakeup_capable - Set/reset device wakeup capability flag.
 401  * @dev: Device to handle.
 402  * @capable: Whether or not @dev is capable of waking up the system from sleep.
 403  *
 404  * If @capable is set, set the @dev's power.can_wakeup flag and add its
 405  * wakeup-related attributes to sysfs.  Otherwise, unset the @dev's
 406  * power.can_wakeup flag and remove its wakeup-related attributes from sysfs.
 407  *
 408  * This function may sleep and it can't be called from any context where
 409  * sleeping is not allowed.
 410  */
 411 void device_set_wakeup_capable(struct device *dev, bool capable)
 412 {
 413         if (!!dev->power.can_wakeup == !!capable)
 414                 return;
 415
 416         if (device_is_registered(dev) && !list_empty(&dev->power.entry)) {
 417                 if (capable) {
 418                         if (wakeup_sysfs_add(dev))
 419                                 return;
 420                 } else {
 421                         wakeup_sysfs_remove(dev);
 422                 }
 423         }
 424         dev->power.can_wakeup = capable;
 425 }
 426 EXPORT_SYMBOL_GPL(device_set_wakeup_capable);
 427
 428 /**
 429  * device_init_wakeup - Device wakeup initialization.
 430  * @dev: Device to handle.
 431  * @enable: Whether or not to enable @dev as a wakeup device.
 432  *
 433  * By default, most devices should leave wakeup disabled.  The exceptions are
 434  * devices that everyone expects to be wakeup sources: keyboards, power buttons,
 435  * possibly network interfaces, etc.  Also, devices that don't generate their
 436  * own wakeup requests but merely forward requests from one bus to another
 437  * (like PCI bridges) should have wakeup enabled by default.
 438  */
 439 int device_init_wakeup(struct device *dev, bool enable)
 440 {
 441         int ret = 0;
 442
 443         if (!dev)
 444                 return -EINVAL;
 445
 446         if (enable) {
 447                 device_set_wakeup_capable(dev, true);
 448                 ret = device_wakeup_enable(dev);
 449         } else {
 450                 if (dev->power.can_wakeup)
 451                         device_wakeup_disable(dev);
 452
 453                 device_set_wakeup_capable(dev, false);
 454         }
 455
 456         return ret;
 457 }
 458 EXPORT_SYMBOL_GPL(device_init_wakeup);
 459
 460 /**
 461  * device_set_wakeup_enable - Enable or disable a device to wake up the system.
 462  * @dev: Device to handle.
 463  */
 464 int device_set_wakeup_enable(struct device *dev, bool enable)
 465 {
 466         if (!dev || !dev->power.can_wakeup)
 467                 return -EINVAL;
 468
 469         return enable ? device_wakeup_enable(dev) : device_wakeup_disable(dev);
 470 }
 471 EXPORT_SYMBOL_GPL(device_set_wakeup_enable);
 472
 473 /**
 474  * wakeup_source_not_registered - validate the given wakeup source.
 475  * @ws: Wakeup source to be validated.
 476  */
 477 static bool wakeup_source_not_registered(struct wakeup_source *ws)
 478 {
 479         /*
 480          * Use timer struct to check if the given source is initialized
 481          * by wakeup_source_add.
 482          */
 483         return ws->timer.function != pm_wakeup_timer_fn ||
 484                    ws->timer.data != (unsigned long)ws;
 485 }
 486
 487 /*
 488  * The functions below use the observation that each wakeup event starts a
 489  * period in which the system should not be suspended.  The moment this period
 490  * will end depends on how the wakeup event is going to be processed after being
 491  * detected and all of the possible cases can be divided into two distinct
 492  * groups.
 493  *
 494  * First, a wakeup event may be detected by the same functional unit that will
 495  * carry out the entire processing of it and possibly will pass it to user space
 496  * for further processing.  In that case the functional unit that has detected
 497  * the event may later "close" the "no suspend" period associated with it
 498  * directly as soon as it has been dealt with.  The pair of pm_stay_awake() and
 499  * pm_relax(), balanced with each other, is supposed to be used in such
 500  * situations.
 501  *
 502  * Second, a wakeup event may be detected by one functional unit and processed
 503  * by another one.  In that case the unit that has detected it cannot really
 504  * "close" the "no suspend" period associated with it, unless it knows in
 505  * advance what's going to happen to the event during processing.  This
 506  * knowledge, however, may not be available to it, so it can simply specify time
 507  * to wait before the system can be suspended and pass it as the second
 508  * argument of pm_wakeup_event().
 509  *
 510  * It is valid to call pm_relax() after pm_wakeup_event(), in which case the
 511  * "no suspend" period will be ended either by the pm_relax(), or by the timer
 512  * function executed when the timer expires, whichever comes first.
 513  */
 514
 515 /**
 516  * wakup_source_activate - Mark given wakeup source as active.
 517  * @ws: Wakeup source to handle.
 518  *
 519  * Update the @ws' statistics and, if @ws has just been activated, notify the PM
 520  * core of the event by incrementing the counter of of wakeup events being
 521  * processed.
 522  */
 523 static void wakeup_source_activate(struct wakeup_source *ws)
 524 {
 525         unsigned int cec;
 526
 527         if (WARN_ONCE(wakeup_source_not_registered(ws),
 528                         "unregistered wakeup source\n"))
 529                 return;
 530
 531         /*
 532          * active wakeup source should bring the system
 533          * out of PM_SUSPEND_FREEZE state
 534          */
 535         freeze_wake();
 536
 537         ws->active = true;
 538         ws->active_count++;
 539         ws->last_time = ktime_get();
 540         if (ws->autosleep_enabled)
 541                 ws->start_prevent_time = ws->last_time;
 542
 543         /* Increment the counter of events in progress. */
 544         cec = atomic_inc_return(&combined_event_count);
 545
 546         trace_wakeup_source_activate(ws->name, cec);
 547 }
 548
 549 /**
 550  * wakeup_source_report_event - Report wakeup event using the given source.
 551  * @ws: Wakeup source to report the event for.
 552  */
 553 static void wakeup_source_report_event(struct wakeup_source *ws)
 554 {
 555         ws->event_count++;
 556         /* This is racy, but the counter is approximate anyway. */
 557         if (events_check_enabled)
 558                 ws->wakeup_count++;
 559
 560         if (!ws->active)
 561                 wakeup_source_activate(ws);
 562 }
 563
 564 /**
 565  * __pm_stay_awake - Notify the PM core of a wakeup event.
 566  * @ws: Wakeup source object associated with the source of the event.
 567  *
 568  * It is safe to call this function from interrupt context.
 569  */
 570 void __pm_stay_awake(struct wakeup_source *ws)
 571 {
 572         unsigned long flags;
 573
 574         if (!ws)
 575                 return;
 576
 577         spin_lock_irqsave(&ws->lock, flags);
 578
 579         wakeup_source_report_event(ws);
 580         del_timer(&ws->timer);
 581         ws->timer_expires = 0;
 582
 583         spin_unlock_irqrestore(&ws->lock, flags);
 584 }
 585 EXPORT_SYMBOL_GPL(__pm_stay_awake);
 586
 587 /**
 588  * pm_stay_awake - Notify the PM core that a wakeup event is being processed.
 589  * @dev: Device the wakeup event is related to.
 590  *
 591  * Notify the PM core of a wakeup event (signaled by @dev) by calling
 592  * __pm_stay_awake for the @dev's wakeup source object.
 593  *
 594  * Call this function after detecting of a wakeup event if pm_relax() is going
 595  * to be called directly after processing the event (and possibly passing it to
 596  * user space for further processing).
 597  */
 598 void pm_stay_awake(struct device *dev)
 599 {
 600         unsigned long flags;
 601
 602         if (!dev)
 603                 return;
 604
 605         spin_lock_irqsave(&dev->power.lock, flags);
 606         __pm_stay_awake(dev->power.wakeup);
 607         spin_unlock_irqrestore(&dev->power.lock, flags);
 608 }
 609 EXPORT_SYMBOL_GPL(pm_stay_awake);
 610
 611 #ifdef CONFIG_PM_AUTOSLEEP
 612 static void update_prevent_sleep_time(struct wakeup_source *ws, ktime_t now)
 613 {
 614         ktime_t delta = ktime_sub(now, ws->start_prevent_time);
 615         ws->prevent_sleep_time = ktime_add(ws->prevent_sleep_time, delta);
 616 }
 617 #else
 618 static inline void update_prevent_sleep_time(struct wakeup_source *ws,
 619                                              ktime_t now) {}
 620 #endif
 621
 622 /**
 623  * wakup_source_deactivate - Mark given wakeup source as inactive.
 624  * @ws: Wakeup source to handle.
 625  *
 626  * Update the @ws' statistics and notify the PM core that the wakeup source has
 627  * become inactive by decrementing the counter of wakeup events being processed
 628  * and incrementing the counter of registered wakeup events.
 629  */
 630 static void wakeup_source_deactivate(struct wakeup_source *ws)
 631 {
 632         unsigned int cnt, inpr, cec;
 633         ktime_t duration;
 634         ktime_t now;
 635
 636         ws->relax_count++;
 637         /*
 638          * __pm_relax() may be called directly or from a timer function.
 639          * If it is called directly right after the timer function has been
 640          * started, but before the timer function calls __pm_relax(), it is
 641          * possible that __pm_stay_awake() will be called in the meantime and
 642          * will set ws->active.  Then, ws->active may be cleared immediately
 643          * by the __pm_relax() called from the timer function, but in such a
 644          * case ws->relax_count will be different from ws->active_count.
 645          */
 646         if (ws->relax_count != ws->active_count) {
 647                 ws->relax_count--;
 648                 return;
 649         }
 650
 651         ws->active = false;
 652
 653         now = ktime_get();
 654         duration = ktime_sub(now, ws->last_time);
 655         ws->total_time = ktime_add(ws->total_time, duration);
 656         if (ktime_to_ns(duration) > ktime_to_ns(ws->max_time))
 657                 ws->max_time = duration;
 658
 659         ws->last_time = now;
 660         del_timer(&ws->timer);
 661         ws->timer_expires = 0;
 662
 663         if (ws->autosleep_enabled)
 664                 update_prevent_sleep_time(ws, now);
 665
 666         /*
 667          * Increment the counter of registered wakeup events and decrement the
 668          * couter of wakeup events in progress simultaneously.
 669          */
 670         cec = atomic_add_return(MAX_IN_PROGRESS, &combined_event_count);
 671         trace_wakeup_source_deactivate(ws->name, cec);
 672
 673         split_counters(&cnt, &inpr);
 674         if (!inpr && waitqueue_active(&wakeup_count_wait_queue))
 675                 wake_up(&wakeup_count_wait_queue);
 676 }
 677
 678 /**
 679  * __pm_relax - Notify the PM core that processing of a wakeup event has ended.
 680  * @ws: Wakeup source object associated with the source of the event.
 681  *
 682  * Call this function for wakeup events whose processing started with calling
 683  * __pm_stay_awake().
 684  *
 685  * It is safe to call it from interrupt context.
 686  */
 687 void __pm_relax(struct wakeup_source *ws)
 688 {
 689         unsigned long flags;
 690
 691         if (!ws)
 692                 return;
 693
 694         spin_lock_irqsave(&ws->lock, flags);
 695         if (ws->active)
 696                 wakeup_source_deactivate(ws);
 697         spin_unlock_irqrestore(&ws->lock, flags);
 698 }
 699 EXPORT_SYMBOL_GPL(__pm_relax);
 700
 701 /**
 702  * pm_relax - Notify the PM core that processing of a wakeup event has ended.
 703  * @dev: Device that signaled the event.
 704  *
 705  * Execute __pm_relax() for the @dev's wakeup source object.
 706  */
 707 void pm_relax(struct device *dev)
 708 {
 709         unsigned long flags;
 710
 711         if (!dev)
 712                 return;
 713
 714         spin_lock_irqsave(&dev->power.lock, flags);
 715         __pm_relax(dev->power.wakeup);
 716         spin_unlock_irqrestore(&dev->power.lock, flags);
 717 }
 718 EXPORT_SYMBOL_GPL(pm_relax);
 719
 720 /**
 721  * pm_wakeup_timer_fn - Delayed finalization of a wakeup event.
 722  * @data: Address of the wakeup source object associated with the event source.
 723  *
 724  * Call wakeup_source_deactivate() for the wakeup source whose address is stored
 725  * in @data if it is currently active and its timer has not been canceled and
 726  * the expiration time of the timer is not in future.
 727  */
 728 static void pm_wakeup_timer_fn(unsigned long data)
 729 {
 730         struct wakeup_source *ws = (struct wakeup_source *)data;
 731         unsigned long flags;
 732
 733         spin_lock_irqsave(&ws->lock, flags);
 734
 735         if (ws->active && ws->timer_expires
 736             && time_after_eq(jiffies, ws->timer_expires)) {
 737                 wakeup_source_deactivate(ws);
 738                 ws->expire_count++;
 739         }
 740
 741         spin_unlock_irqrestore(&ws->lock, flags);
 742 }
 743
 744 /**
 745  * __pm_wakeup_event - Notify the PM core of a wakeup event.
 746  * @ws: Wakeup source object associated with the event source.
 747  * @msec: Anticipated event processing time (in milliseconds).
 748  *
 749  * Notify the PM core of a wakeup event whose source is @ws that will take
 750  * approximately @msec milliseconds to be processed by the kernel.  If @ws is
 751  * not active, activate it.  If @msec is nonzero, set up the @ws' timer to
 752  * execute pm_wakeup_timer_fn() in future.
 753  *
 754  * It is safe to call this function from interrupt context.
 755  */
 756 void __pm_wakeup_event(struct wakeup_source *ws, unsigned int msec)
 757 {
 758         unsigned long flags;
 759         unsigned long expires;
 760
 761         if (!ws)
 762                 return;
 763
 764         spin_lock_irqsave(&ws->lock, flags);
 765
 766         wakeup_source_report_event(ws);
 767
 768         if (!msec) {
 769                 wakeup_source_deactivate(ws);
 770                 goto unlock;
 771         }
 772
 773         expires = jiffies + msecs_to_jiffies(msec);
 774         if (!expires)
 775                 expires = 1;
 776
 777         if (!ws->timer_expires || time_after(expires, ws->timer_expires)) {
 778                 mod_timer(&ws->timer, expires);
 779                 ws->timer_expires = expires;
 780         }
 781
 782  unlock:
 783         spin_unlock_irqrestore(&ws->lock, flags);
 784 }
 785 EXPORT_SYMBOL_GPL(__pm_wakeup_event);
 786
 787
 788 /**
 789  * pm_wakeup_event - Notify the PM core of a wakeup event.
 790  * @dev: Device the wakeup event is related to.
 791  * @msec: Anticipated event processing time (in milliseconds).
 792  *
 793  * Call __pm_wakeup_event() for the @dev's wakeup source object.
 794  */
 795 void pm_wakeup_event(struct device *dev, unsigned int msec)
 796 {
 797         unsigned long flags;
 798
 799         if (!dev)
 800                 return;
 801
 802         spin_lock_irqsave(&dev->power.lock, flags);
 803         __pm_wakeup_event(dev->power.wakeup, msec);
 804         spin_unlock_irqrestore(&dev->power.lock, flags);
 805 }
 806 EXPORT_SYMBOL_GPL(pm_wakeup_event);
 807
 808 void pm_get_active_wakeup_sources(char *pending_wakeup_source, size_t max)
 809 {
 810         struct wakeup_source *ws, *last_active_ws = NULL;
 811         int len = 0;
 812         bool active = false;
 813
 814         rcu_read_lock();
 815         list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
 816                 if (ws->active && len < max) {
 817                         if (!active)
 818                                 len += scnprintf(pending_wakeup_source, max,
 819                                                 "Pending Wakeup Sources: ");
 820                         len += scnprintf(pending_wakeup_source + len, max - len,
 821                                 "%s ", ws->name);
 822                         active = true;
 823                 } else if (!active &&
 824                            (!last_active_ws ||
 825                             ktime_to_ns(ws->last_time) >
 826                             ktime_to_ns(last_active_ws->last_time))) {
 827                         last_active_ws = ws;
 828                 }
 829         }
 830         if (!active && last_active_ws) {
 831                 scnprintf(pending_wakeup_source, max,
 832                                 "Last active Wakeup Source: %s",
 833                                 last_active_ws->name);
 834         }
 835         rcu_read_unlock();
 836 }
 837 EXPORT_SYMBOL_GPL(pm_get_active_wakeup_sources);
 838
 839 void pm_print_active_wakeup_sources(void)
 840 {
 841         struct wakeup_source *ws;
 842         int active = 0;
 843         struct wakeup_source *last_activity_ws = NULL;
 844
 845         rcu_read_lock();
 846         list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
 847                 if (ws->active) {
 848                         pr_info("active wakeup source: %s\n", ws->name);
 849                         active = 1;
 850                 } else if (!active &&
 851                            (!last_activity_ws ||
 852                             ktime_to_ns(ws->last_time) >
 853                             ktime_to_ns(last_activity_ws->last_time))) {
 854                         last_activity_ws = ws;
 855                 }
 856         }
 857
 858         if (!active && last_activity_ws)
 859                 pr_info("last active wakeup source: %s\n",
 860                         last_activity_ws->name);
 861         rcu_read_unlock();
 862 }
 863 EXPORT_SYMBOL_GPL(pm_print_active_wakeup_sources);
 864
 865 /**
 866  * pm_wakeup_pending - Check if power transition in progress should be aborted.
 867  *
 868  * Compare the current number of registered wakeup events with its preserved
 869  * value from the past and return true if new wakeup events have been registered
 870  * since the old value was stored.  Also return true if the current number of
 871  * wakeup events being processed is different from zero.
 872  */
 873 bool pm_wakeup_pending(void)
 874 {
 875         unsigned long flags;
 876         bool ret = false;
 877
 878         spin_lock_irqsave(&events_lock, flags);
 879         if (events_check_enabled) {
 880                 unsigned int cnt, inpr;
 881
 882                 split_counters(&cnt, &inpr);
 883                 ret = (cnt != saved_count || inpr > 0);
 884                 events_check_enabled = !ret;
 885         }
 886         spin_unlock_irqrestore(&events_lock, flags);
 887
 888         if (ret) {
 889                 pr_info("PM: Wakeup pending, aborting suspend\n");
 890                 pm_print_active_wakeup_sources();
 891         }
 892
 893         return ret || pm_abort_suspend;
 894 }
 895
 896 void pm_system_wakeup(void)
 897 {
 898         pm_abort_suspend = true;
 899         freeze_wake();
 900 }
 901 EXPORT_SYMBOL_GPL(pm_system_wakeup);
 902
 903 void pm_wakeup_clear(void)
 904 {
 905         pm_abort_suspend = false;
 906         pm_wakeup_irq = 0;
 907 }
 908
 909 void pm_system_irq_wakeup(unsigned int irq_number)
 910 {
 911         if (pm_wakeup_irq == 0) {
 912                 pm_wakeup_irq = irq_number;
 913                 pm_system_wakeup();
 914         }
 915 }
 916
 917 /**
 918  * pm_get_wakeup_count - Read the number of registered wakeup events.
 919  * @count: Address to store the value at.
 920  * @block: Whether or not to block.
 921  *
 922  * Store the number of registered wakeup events at the address in @count.  If
 923  * @block is set, block until the current number of wakeup events being
 924  * processed is zero.
 925  *
 926  * Return 'false' if the current number of wakeup events being processed is
 927  * nonzero.  Otherwise return 'true'.
 928  */
 929 bool pm_get_wakeup_count(unsigned int *count, bool block)
 930 {
 931         unsigned int cnt, inpr;
 932
 933         if (block) {
 934                 DEFINE_WAIT(wait);
 935
 936                 for (;;) {
 937                         prepare_to_wait(&wakeup_count_wait_queue, &wait,
 938                                         TASK_INTERRUPTIBLE);
 939                         split_counters(&cnt, &inpr);
 940                         if (inpr == 0 || signal_pending(current))
 941                                 break;
 942
 943                         schedule();
 944                 }
 945                 finish_wait(&wakeup_count_wait_queue, &wait);
 946         }
 947
 948         split_counters(&cnt, &inpr);
 949         *count = cnt;
 950         return !inpr;
 951 }
 952
 953 /**
 954  * pm_save_wakeup_count - Save the current number of registered wakeup events.
 955  * @count: Value to compare with the current number of registered wakeup events.
 956  *
 957  * If @count is equal to the current number of registered wakeup events and the
 958  * current number of wakeup events being processed is zero, store @count as the
 959  * old number of registered wakeup events for pm_check_wakeup_events(), enable
 960  * wakeup events detection and return 'true'.  Otherwise disable wakeup events
 961  * detection and return 'false'.
 962  */
 963 bool pm_save_wakeup_count(unsigned int count)
 964 {
 965         unsigned int cnt, inpr;
 966         unsigned long flags;
 967
 968         events_check_enabled = false;
 969         spin_lock_irqsave(&events_lock, flags);
 970         split_counters(&cnt, &inpr);
 971         if (cnt == count && inpr == 0) {
 972                 saved_count = count;
 973                 events_check_enabled = true;
 974         }
 975         spin_unlock_irqrestore(&events_lock, flags);
 976         return events_check_enabled;
 977 }
 978
 979 #ifdef CONFIG_PM_AUTOSLEEP
 980 /**
 981  * pm_wakep_autosleep_enabled - Modify autosleep_enabled for all wakeup sources.
 982  * @enabled: Whether to set or to clear the autosleep_enabled flags.
 983  */
 984 void pm_wakep_autosleep_enabled(bool set)
 985 {
 986         struct wakeup_source *ws;
 987         ktime_t now = ktime_get();
 988
 989         rcu_read_lock();
 990         list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
 991                 spin_lock_irq(&ws->lock);
 992                 if (ws->autosleep_enabled != set) {
 993                         ws->autosleep_enabled = set;
 994                         if (ws->active) {
 995                                 if (set)
 996                                         ws->start_prevent_time = now;
 997                                 else
 998                                         update_prevent_sleep_time(ws, now);
 999                         }
1000                 }
1001                 spin_unlock_irq(&ws->lock);
1002         }
1003         rcu_read_unlock();
1004 }
1005 #endif /* CONFIG_PM_AUTOSLEEP */
1006
1007 static struct dentry *wakeup_sources_stats_dentry;
1008
1009 /**
1010  * print_wakeup_source_stats - Print wakeup source statistics information.
1011  * @m: seq_file to print the statistics into.
1012  * @ws: Wakeup source object to print the statistics for.
1013  */
1014 static int print_wakeup_source_stats(struct seq_file *m,
1015                                      struct wakeup_source *ws)
1016 {
1017         unsigned long flags;
1018         ktime_t total_time;
1019         ktime_t max_time;
1020         unsigned long active_count;
1021         ktime_t active_time;
1022         ktime_t prevent_sleep_time;
1023
1024         spin_lock_irqsave(&ws->lock, flags);
1025
1026         total_time = ws->total_time;
1027         max_time = ws->max_time;
1028         prevent_sleep_time = ws->prevent_sleep_time;
1029         active_count = ws->active_count;
1030         if (ws->active) {
1031                 ktime_t now = ktime_get();
1032
1033                 active_time = ktime_sub(now, ws->last_time);
1034                 total_time = ktime_add(total_time, active_time);
1035                 if (active_time.tv64 > max_time.tv64)
1036                         max_time = active_time;
1037
1038                 if (ws->autosleep_enabled)
1039                         prevent_sleep_time = ktime_add(prevent_sleep_time,
1040                                 ktime_sub(now, ws->start_prevent_time));
1041         } else {
1042                 active_time = ktime_set(0, 0);
1043         }
1044
1045         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",
1046                    ws->name, active_count, ws->event_count,
1047                    ws->wakeup_count, ws->expire_count,
1048                    ktime_to_ms(active_time), ktime_to_ms(total_time),
1049                    ktime_to_ms(max_time), ktime_to_ms(ws->last_time),
1050                    ktime_to_ms(prevent_sleep_time));
1051
1052         spin_unlock_irqrestore(&ws->lock, flags);
1053
1054         return 0;
1055 }
1056
1057 /**
1058  * wakeup_sources_stats_show - Print wakeup sources statistics information.
1059  * @m: seq_file to print the statistics into.
1060  */
1061 static int wakeup_sources_stats_show(struct seq_file *m, void *unused)
1062 {
1063         struct wakeup_source *ws;
1064
1065         seq_puts(m, "name\t\tactive_count\tevent_count\twakeup_count\t"
1066                 "expire_count\tactive_since\ttotal_time\tmax_time\t"
1067                 "last_change\tprevent_suspend_time\n");
1068
1069         rcu_read_lock();
1070         list_for_each_entry_rcu(ws, &wakeup_sources, entry)
1071                 print_wakeup_source_stats(m, ws);
1072         rcu_read_unlock();
1073
1074         print_wakeup_source_stats(m, &deleted_ws);
1075
1076         return 0;
1077 }
1078
1079 static int wakeup_sources_stats_open(struct inode *inode, struct file *file)
1080 {
1081         return single_open(file, wakeup_sources_stats_show, NULL);
1082 }
1083
1084 static const struct file_operations wakeup_sources_stats_fops = {
1085         .owner = THIS_MODULE,
1086         .open = wakeup_sources_stats_open,
1087         .read = seq_read,
1088         .llseek = seq_lseek,
1089         .release = single_release,
1090 };
1091
1092 static int __init wakeup_sources_debugfs_init(void)
1093 {
1094         wakeup_sources_stats_dentry = debugfs_create_file("wakeup_sources",
1095                         S_IRUGO, NULL, NULL, &wakeup_sources_stats_fops);
1096         return 0;
1097 }
1098
1099 postcore_initcall(wakeup_sources_debugfs_init);