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