drivers/base/power/wakeup.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * drivers/base/power/wakeup.c - System wakeup events framework
   4  *
   5  * Copyright (c) 2010 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
   6  */
   7 #define pr_fmt(fmt) "PM: " fmt
   8
   9 #include <linux/device.h>
  10 #include <linux/slab.h>
  11 #include <linux/sched/signal.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 #ifndef CONFIG_SUSPEND
  23 suspend_state_t pm_suspend_target_state;
  24 #define pm_suspend_target_state (PM_SUSPEND_ON)
  25 #endif
  26
  27 #define list_for_each_entry_rcu_locked(pos, head, member) \
  28         list_for_each_entry_rcu(pos, head, member, \
  29                 srcu_read_lock_held(&wakeup_srcu))
  30 /*
  31  * If set, the suspend/hibernate code will abort transitions to a sleep state
  32  * if wakeup events are registered during or immediately before the transition.
  33  */
  34 bool events_check_enabled __read_mostly;
  35
  36 /* First wakeup IRQ seen by the kernel in the last cycle. */
  37 static unsigned int wakeup_irq[2] __read_mostly;
  38 static DEFINE_RAW_SPINLOCK(wakeup_irq_lock);
  39
  40 /* If greater than 0 and the system is suspending, terminate the suspend. */
  41 static atomic_t pm_abort_suspend __read_mostly;
  42
  43 /*
  44  * Combined counters of registered wakeup events and wakeup events in progress.
  45  * They need to be modified together atomically, so it's better to use one
  46  * atomic variable to hold them both.
  47  */
  48 static atomic_t combined_event_count = ATOMIC_INIT(0);
  49
  50 #define IN_PROGRESS_BITS        (sizeof(int) * 4)
  51 #define MAX_IN_PROGRESS         ((1 << IN_PROGRESS_BITS) - 1)
  52
  53 static void split_counters(unsigned int *cnt, unsigned int *inpr)
  54 {
  55         unsigned int comb = atomic_read(&combined_event_count);
  56
  57         *cnt = (comb >> IN_PROGRESS_BITS);
  58         *inpr = comb & MAX_IN_PROGRESS;
  59 }
  60
  61 /* A preserved old value of the events counter. */
  62 static unsigned int saved_count;
  63
  64 static DEFINE_RAW_SPINLOCK(events_lock);
  65
  66 static void pm_wakeup_timer_fn(struct timer_list *t);
  67
  68 static LIST_HEAD(wakeup_sources);
  69
  70 static DECLARE_WAIT_QUEUE_HEAD(wakeup_count_wait_queue);
  71
  72 DEFINE_STATIC_SRCU(wakeup_srcu);
  73
  74 static struct wakeup_source deleted_ws = {
  75         .name = "deleted",
  76         .lock =  __SPIN_LOCK_UNLOCKED(deleted_ws.lock),
  77 };
  78
  79 static DEFINE_IDA(wakeup_ida);
  80
  81 /**
  82  * wakeup_source_create - Create a struct wakeup_source object.
  83  * @name: Name of the new wakeup source.
  84  */
  85 struct wakeup_source *wakeup_source_create(const char *name)
  86 {
  87         struct wakeup_source *ws;
  88         const char *ws_name;
  89         int id;
  90
  91         ws = kzalloc(sizeof(*ws), GFP_KERNEL);
  92         if (!ws)
  93                 goto err_ws;
  94
  95         ws_name = kstrdup_const(name, GFP_KERNEL);
  96         if (!ws_name)
  97                 goto err_name;
  98         ws->name = ws_name;
  99
 100         id = ida_alloc(&wakeup_ida, GFP_KERNEL);
 101         if (id < 0)
 102                 goto err_id;
 103         ws->id = id;
 104
 105         return ws;
 106
 107 err_id:
 108         kfree_const(ws->name);
 109 err_name:
 110         kfree(ws);
 111 err_ws:
 112         return NULL;
 113 }
 114 EXPORT_SYMBOL_GPL(wakeup_source_create);
 115
 116 /*
 117  * Record wakeup_source statistics being deleted into a dummy wakeup_source.
 118  */
 119 static void wakeup_source_record(struct wakeup_source *ws)
 120 {
 121         unsigned long flags;
 122
 123         spin_lock_irqsave(&deleted_ws.lock, flags);
 124
 125         if (ws->event_count) {
 126                 deleted_ws.total_time =
 127                         ktime_add(deleted_ws.total_time, ws->total_time);
 128                 deleted_ws.prevent_sleep_time =
 129                         ktime_add(deleted_ws.prevent_sleep_time,
 130                                   ws->prevent_sleep_time);
 131                 deleted_ws.max_time =
 132                         ktime_compare(deleted_ws.max_time, ws->max_time) > 0 ?
 133                                 deleted_ws.max_time : ws->max_time;
 134                 deleted_ws.event_count += ws->event_count;
 135                 deleted_ws.active_count += ws->active_count;
 136                 deleted_ws.relax_count += ws->relax_count;
 137                 deleted_ws.expire_count += ws->expire_count;
 138                 deleted_ws.wakeup_count += ws->wakeup_count;
 139         }
 140
 141         spin_unlock_irqrestore(&deleted_ws.lock, flags);
 142 }
 143
 144 static void wakeup_source_free(struct wakeup_source *ws)
 145 {
 146         ida_free(&wakeup_ida, ws->id);
 147         kfree_const(ws->name);
 148         kfree(ws);
 149 }
 150
 151 /**
 152  * wakeup_source_destroy - Destroy a struct wakeup_source object.
 153  * @ws: Wakeup source to destroy.
 154  *
 155  * Use only for wakeup source objects created with wakeup_source_create().
 156  */
 157 void wakeup_source_destroy(struct wakeup_source *ws)
 158 {
 159         if (!ws)
 160                 return;
 161
 162         __pm_relax(ws);
 163         wakeup_source_record(ws);
 164         wakeup_source_free(ws);
 165 }
 166 EXPORT_SYMBOL_GPL(wakeup_source_destroy);
 167
 168 /**
 169  * wakeup_source_add - Add given object to the list of wakeup sources.
 170  * @ws: Wakeup source object to add to the list.
 171  */
 172 void wakeup_source_add(struct wakeup_source *ws)
 173 {
 174         unsigned long flags;
 175
 176         if (WARN_ON(!ws))
 177                 return;
 178
 179         spin_lock_init(&ws->lock);
 180         timer_setup(&ws->timer, pm_wakeup_timer_fn, 0);
 181         ws->active = false;
 182
 183         raw_spin_lock_irqsave(&events_lock, flags);
 184         list_add_rcu(&ws->entry, &wakeup_sources);
 185         raw_spin_unlock_irqrestore(&events_lock, flags);
 186 }
 187 EXPORT_SYMBOL_GPL(wakeup_source_add);
 188
 189 /**
 190  * wakeup_source_remove - Remove given object from the wakeup sources list.
 191  * @ws: Wakeup source object to remove from the list.
 192  */
 193 void wakeup_source_remove(struct wakeup_source *ws)
 194 {
 195         unsigned long flags;
 196
 197         if (WARN_ON(!ws))
 198                 return;
 199
 200         raw_spin_lock_irqsave(&events_lock, flags);
 201         list_del_rcu(&ws->entry);
 202         raw_spin_unlock_irqrestore(&events_lock, flags);
 203         synchronize_srcu(&wakeup_srcu);
 204
 205         del_timer_sync(&ws->timer);
 206         /*
 207          * Clear timer.function to make wakeup_source_not_registered() treat
 208          * this wakeup source as not registered.
 209          */
 210         ws->timer.function = NULL;
 211 }
 212 EXPORT_SYMBOL_GPL(wakeup_source_remove);
 213
 214 /**
 215  * wakeup_source_register - Create wakeup source and add it to the list.
 216  * @dev: Device this wakeup source is associated with (or NULL if virtual).
 217  * @name: Name of the wakeup source to register.
 218  */
 219 struct wakeup_source *wakeup_source_register(struct device *dev,
 220                                              const char *name)
 221 {
 222         struct wakeup_source *ws;
 223         int ret;
 224
 225         ws = wakeup_source_create(name);
 226         if (ws) {
 227                 if (!dev || device_is_registered(dev)) {
 228                         ret = wakeup_source_sysfs_add(dev, ws);
 229                         if (ret) {
 230                                 wakeup_source_free(ws);
 231                                 return NULL;
 232                         }
 233                 }
 234                 wakeup_source_add(ws);
 235         }
 236         return ws;
 237 }
 238 EXPORT_SYMBOL_GPL(wakeup_source_register);
 239
 240 /**
 241  * wakeup_source_unregister - Remove wakeup source from the list and remove it.
 242  * @ws: Wakeup source object to unregister.
 243  */
 244 void wakeup_source_unregister(struct wakeup_source *ws)
 245 {
 246         if (ws) {
 247                 wakeup_source_remove(ws);
 248                 if (ws->dev)
 249                         wakeup_source_sysfs_remove(ws);
 250
 251                 wakeup_source_destroy(ws);
 252         }
 253 }
 254 EXPORT_SYMBOL_GPL(wakeup_source_unregister);
 255
 256 /**
 257  * wakeup_sources_read_lock - Lock wakeup source list for read.
 258  *
 259  * Returns an index of srcu lock for struct wakeup_srcu.
 260  * This index must be passed to the matching wakeup_sources_read_unlock().
 261  */
 262 int wakeup_sources_read_lock(void)
 263 {
 264         return srcu_read_lock(&wakeup_srcu);
 265 }
 266 EXPORT_SYMBOL_GPL(wakeup_sources_read_lock);
 267
 268 /**
 269  * wakeup_sources_read_unlock - Unlock wakeup source list.
 270  * @idx: return value from corresponding wakeup_sources_read_lock()
 271  */
 272 void wakeup_sources_read_unlock(int idx)
 273 {
 274         srcu_read_unlock(&wakeup_srcu, idx);
 275 }
 276 EXPORT_SYMBOL_GPL(wakeup_sources_read_unlock);
 277
 278 /**
 279  * wakeup_sources_walk_start - Begin a walk on wakeup source list
 280  *
 281  * Returns first object of the list of wakeup sources.
 282  *
 283  * Note that to be safe, wakeup sources list needs to be locked by calling
 284  * wakeup_source_read_lock() for this.
 285  */
 286 struct wakeup_source *wakeup_sources_walk_start(void)
 287 {
 288         struct list_head *ws_head = &wakeup_sources;
 289
 290         return list_entry_rcu(ws_head->next, struct wakeup_source, entry);
 291 }
 292 EXPORT_SYMBOL_GPL(wakeup_sources_walk_start);
 293
 294 /**
 295  * wakeup_sources_walk_next - Get next wakeup source from the list
 296  * @ws: Previous wakeup source object
 297  *
 298  * Note that to be safe, wakeup sources list needs to be locked by calling
 299  * wakeup_source_read_lock() for this.
 300  */
 301 struct wakeup_source *wakeup_sources_walk_next(struct wakeup_source *ws)
 302 {
 303         struct list_head *ws_head = &wakeup_sources;
 304
 305         return list_next_or_null_rcu(ws_head, &ws->entry,
 306                                 struct wakeup_source, entry);
 307 }
 308 EXPORT_SYMBOL_GPL(wakeup_sources_walk_next);
 309
 310 /**
 311  * device_wakeup_attach - Attach a wakeup source object to a device object.
 312  * @dev: Device to handle.
 313  * @ws: Wakeup source object to attach to @dev.
 314  *
 315  * This causes @dev to be treated as a wakeup device.
 316  */
 317 static int device_wakeup_attach(struct device *dev, struct wakeup_source *ws)
 318 {
 319         spin_lock_irq(&dev->power.lock);
 320         if (dev->power.wakeup) {
 321                 spin_unlock_irq(&dev->power.lock);
 322                 return -EEXIST;
 323         }
 324         dev->power.wakeup = ws;
 325         if (dev->power.wakeirq)
 326                 device_wakeup_attach_irq(dev, dev->power.wakeirq);
 327         spin_unlock_irq(&dev->power.lock);
 328         return 0;
 329 }
 330
 331 /**
 332  * device_wakeup_enable - Enable given device to be a wakeup source.
 333  * @dev: Device to handle.
 334  *
 335  * Create a wakeup source object, register it and attach it to @dev.
 336  */
 337 int device_wakeup_enable(struct device *dev)
 338 {
 339         struct wakeup_source *ws;
 340         int ret;
 341
 342         if (!dev || !dev->power.can_wakeup)
 343                 return -EINVAL;
 344
 345         if (pm_suspend_target_state != PM_SUSPEND_ON)
 346                 dev_dbg(dev, "Suspicious %s() during system transition!\n", __func__);
 347
 348         ws = wakeup_source_register(dev, dev_name(dev));
 349         if (!ws)
 350                 return -ENOMEM;
 351
 352         ret = device_wakeup_attach(dev, ws);
 353         if (ret)
 354                 wakeup_source_unregister(ws);
 355
 356         return ret;
 357 }
 358 EXPORT_SYMBOL_GPL(device_wakeup_enable);
 359
 360 /**
 361  * device_wakeup_attach_irq - Attach a wakeirq to a wakeup source
 362  * @dev: Device to handle
 363  * @wakeirq: Device specific wakeirq entry
 364  *
 365  * Attach a device wakeirq to the wakeup source so the device
 366  * wake IRQ can be configured automatically for suspend and
 367  * resume.
 368  *
 369  * Call under the device's power.lock lock.
 370  */
 371 void device_wakeup_attach_irq(struct device *dev,
 372                              struct wake_irq *wakeirq)
 373 {
 374         struct wakeup_source *ws;
 375
 376         ws = dev->power.wakeup;
 377         if (!ws)
 378                 return;
 379
 380         if (ws->wakeirq)
 381                 dev_err(dev, "Leftover wakeup IRQ found, overriding\n");
 382
 383         ws->wakeirq = wakeirq;
 384 }
 385
 386 /**
 387  * device_wakeup_detach_irq - Detach a wakeirq from a wakeup source
 388  * @dev: Device to handle
 389  *
 390  * Removes a device wakeirq from the wakeup source.
 391  *
 392  * Call under the device's power.lock lock.
 393  */
 394 void device_wakeup_detach_irq(struct device *dev)
 395 {
 396         struct wakeup_source *ws;
 397
 398         ws = dev->power.wakeup;
 399         if (ws)
 400                 ws->wakeirq = NULL;
 401 }
 402
 403 /**
 404  * device_wakeup_arm_wake_irqs -
 405  *
 406  * Iterates over the list of device wakeirqs to arm them.
 407  */
 408 void device_wakeup_arm_wake_irqs(void)
 409 {
 410         struct wakeup_source *ws;
 411         int srcuidx;
 412
 413         srcuidx = srcu_read_lock(&wakeup_srcu);
 414         list_for_each_entry_rcu_locked(ws, &wakeup_sources, entry)
 415                 dev_pm_arm_wake_irq(ws->wakeirq);
 416         srcu_read_unlock(&wakeup_srcu, srcuidx);
 417 }
 418
 419 /**
 420  * device_wakeup_disarm_wake_irqs -
 421  *
 422  * Iterates over the list of device wakeirqs to disarm them.
 423  */
 424 void device_wakeup_disarm_wake_irqs(void)
 425 {
 426         struct wakeup_source *ws;
 427         int srcuidx;
 428
 429         srcuidx = srcu_read_lock(&wakeup_srcu);
 430         list_for_each_entry_rcu_locked(ws, &wakeup_sources, entry)
 431                 dev_pm_disarm_wake_irq(ws->wakeirq);
 432         srcu_read_unlock(&wakeup_srcu, srcuidx);
 433 }
 434
 435 /**
 436  * device_wakeup_detach - Detach a device's wakeup source object from it.
 437  * @dev: Device to detach the wakeup source object from.
 438  *
 439  * After it returns, @dev will not be treated as a wakeup device any more.
 440  */
 441 static struct wakeup_source *device_wakeup_detach(struct device *dev)
 442 {
 443         struct wakeup_source *ws;
 444
 445         spin_lock_irq(&dev->power.lock);
 446         ws = dev->power.wakeup;
 447         dev->power.wakeup = NULL;
 448         spin_unlock_irq(&dev->power.lock);
 449         return ws;
 450 }
 451
 452 /**
 453  * device_wakeup_disable - Do not regard a device as a wakeup source any more.
 454  * @dev: Device to handle.
 455  *
 456  * Detach the @dev's wakeup source object from it, unregister this wakeup source
 457  * object and destroy it.
 458  */
 459 int device_wakeup_disable(struct device *dev)
 460 {
 461         struct wakeup_source *ws;
 462
 463         if (!dev || !dev->power.can_wakeup)
 464                 return -EINVAL;
 465
 466         ws = device_wakeup_detach(dev);
 467         wakeup_source_unregister(ws);
 468         return 0;
 469 }
 470 EXPORT_SYMBOL_GPL(device_wakeup_disable);
 471
 472 /**
 473  * device_set_wakeup_capable - Set/reset device wakeup capability flag.
 474  * @dev: Device to handle.
 475  * @capable: Whether or not @dev is capable of waking up the system from sleep.
 476  *
 477  * If @capable is set, set the @dev's power.can_wakeup flag and add its
 478  * wakeup-related attributes to sysfs.  Otherwise, unset the @dev's
 479  * power.can_wakeup flag and remove its wakeup-related attributes from sysfs.
 480  *
 481  * This function may sleep and it can't be called from any context where
 482  * sleeping is not allowed.
 483  */
 484 void device_set_wakeup_capable(struct device *dev, bool capable)
 485 {
 486         if (!!dev->power.can_wakeup == !!capable)
 487                 return;
 488
 489         dev->power.can_wakeup = capable;
 490         if (device_is_registered(dev) && !list_empty(&dev->power.entry)) {
 491                 if (capable) {
 492                         int ret = wakeup_sysfs_add(dev);
 493
 494                         if (ret)
 495                                 dev_info(dev, "Wakeup sysfs attributes not added\n");
 496                 } else {
 497                         wakeup_sysfs_remove(dev);
 498                 }
 499         }
 500 }
 501 EXPORT_SYMBOL_GPL(device_set_wakeup_capable);
 502
 503 /**
 504  * device_set_wakeup_enable - Enable or disable a device to wake up the system.
 505  * @dev: Device to handle.
 506  * @enable: enable/disable flag
 507  */
 508 int device_set_wakeup_enable(struct device *dev, bool enable)
 509 {
 510         return enable ? device_wakeup_enable(dev) : device_wakeup_disable(dev);
 511 }
 512 EXPORT_SYMBOL_GPL(device_set_wakeup_enable);
 513
 514 /**
 515  * wakeup_source_not_registered - validate the given wakeup source.
 516  * @ws: Wakeup source to be validated.
 517  */
 518 static bool wakeup_source_not_registered(struct wakeup_source *ws)
 519 {
 520         /*
 521          * Use timer struct to check if the given source is initialized
 522          * by wakeup_source_add.
 523          */
 524         return ws->timer.function != pm_wakeup_timer_fn;
 525 }
 526
 527 /*
 528  * The functions below use the observation that each wakeup event starts a
 529  * period in which the system should not be suspended.  The moment this period
 530  * will end depends on how the wakeup event is going to be processed after being
 531  * detected and all of the possible cases can be divided into two distinct
 532  * groups.
 533  *
 534  * First, a wakeup event may be detected by the same functional unit that will
 535  * carry out the entire processing of it and possibly will pass it to user space
 536  * for further processing.  In that case the functional unit that has detected
 537  * the event may later "close" the "no suspend" period associated with it
 538  * directly as soon as it has been dealt with.  The pair of pm_stay_awake() and
 539  * pm_relax(), balanced with each other, is supposed to be used in such
 540  * situations.
 541  *
 542  * Second, a wakeup event may be detected by one functional unit and processed
 543  * by another one.  In that case the unit that has detected it cannot really
 544  * "close" the "no suspend" period associated with it, unless it knows in
 545  * advance what's going to happen to the event during processing.  This
 546  * knowledge, however, may not be available to it, so it can simply specify time
 547  * to wait before the system can be suspended and pass it as the second
 548  * argument of pm_wakeup_event().
 549  *
 550  * It is valid to call pm_relax() after pm_wakeup_event(), in which case the
 551  * "no suspend" period will be ended either by the pm_relax(), or by the timer
 552  * function executed when the timer expires, whichever comes first.
 553  */
 554
 555 /**
 556  * wakeup_source_activate - Mark given wakeup source as active.
 557  * @ws: Wakeup source to handle.
 558  *
 559  * Update the @ws' statistics and, if @ws has just been activated, notify the PM
 560  * core of the event by incrementing the counter of the wakeup events being
 561  * processed.
 562  */
 563 static void wakeup_source_activate(struct wakeup_source *ws)
 564 {
 565         unsigned int cec;
 566
 567         if (WARN_ONCE(wakeup_source_not_registered(ws),
 568                         "unregistered wakeup source\n"))
 569                 return;
 570
 571         ws->active = true;
 572         ws->active_count++;
 573         ws->last_time = ktime_get();
 574         if (ws->autosleep_enabled)
 575                 ws->start_prevent_time = ws->last_time;
 576
 577         /* Increment the counter of events in progress. */
 578         cec = atomic_inc_return(&combined_event_count);
 579
 580         trace_wakeup_source_activate(ws->name, cec);
 581 }
 582
 583 /**
 584  * wakeup_source_report_event - Report wakeup event using the given source.
 585  * @ws: Wakeup source to report the event for.
 586  * @hard: If set, abort suspends in progress and wake up from suspend-to-idle.
 587  */
 588 static void wakeup_source_report_event(struct wakeup_source *ws, bool hard)
 589 {
 590         ws->event_count++;
 591         /* This is racy, but the counter is approximate anyway. */
 592         if (events_check_enabled)
 593                 ws->wakeup_count++;
 594
 595         if (!ws->active)
 596                 wakeup_source_activate(ws);
 597
 598         if (hard)
 599                 pm_system_wakeup();
 600 }
 601
 602 /**
 603  * __pm_stay_awake - Notify the PM core of a wakeup event.
 604  * @ws: Wakeup source object associated with the source of the event.
 605  *
 606  * It is safe to call this function from interrupt context.
 607  */
 608 void __pm_stay_awake(struct wakeup_source *ws)
 609 {
 610         unsigned long flags;
 611
 612         if (!ws)
 613                 return;
 614
 615         spin_lock_irqsave(&ws->lock, flags);
 616
 617         wakeup_source_report_event(ws, false);
 618         del_timer(&ws->timer);
 619         ws->timer_expires = 0;
 620
 621         spin_unlock_irqrestore(&ws->lock, flags);
 622 }
 623 EXPORT_SYMBOL_GPL(__pm_stay_awake);
 624
 625 /**
 626  * pm_stay_awake - Notify the PM core that a wakeup event is being processed.
 627  * @dev: Device the wakeup event is related to.
 628  *
 629  * Notify the PM core of a wakeup event (signaled by @dev) by calling
 630  * __pm_stay_awake for the @dev's wakeup source object.
 631  *
 632  * Call this function after detecting of a wakeup event if pm_relax() is going
 633  * to be called directly after processing the event (and possibly passing it to
 634  * user space for further processing).
 635  */
 636 void pm_stay_awake(struct device *dev)
 637 {
 638         unsigned long flags;
 639
 640         if (!dev)
 641                 return;
 642
 643         spin_lock_irqsave(&dev->power.lock, flags);
 644         __pm_stay_awake(dev->power.wakeup);
 645         spin_unlock_irqrestore(&dev->power.lock, flags);
 646 }
 647 EXPORT_SYMBOL_GPL(pm_stay_awake);
 648
 649 #ifdef CONFIG_PM_AUTOSLEEP
 650 static void update_prevent_sleep_time(struct wakeup_source *ws, ktime_t now)
 651 {
 652         ktime_t delta = ktime_sub(now, ws->start_prevent_time);
 653         ws->prevent_sleep_time = ktime_add(ws->prevent_sleep_time, delta);
 654 }
 655 #else
 656 static inline void update_prevent_sleep_time(struct wakeup_source *ws,
 657                                              ktime_t now) {}
 658 #endif
 659
 660 /**
 661  * wakeup_source_deactivate - Mark given wakeup source as inactive.
 662  * @ws: Wakeup source to handle.
 663  *
 664  * Update the @ws' statistics and notify the PM core that the wakeup source has
 665  * become inactive by decrementing the counter of wakeup events being processed
 666  * and incrementing the counter of registered wakeup events.
 667  */
 668 static void wakeup_source_deactivate(struct wakeup_source *ws)
 669 {
 670         unsigned int cnt, inpr, cec;
 671         ktime_t duration;
 672         ktime_t now;
 673
 674         ws->relax_count++;
 675         /*
 676          * __pm_relax() may be called directly or from a timer function.
 677          * If it is called directly right after the timer function has been
 678          * started, but before the timer function calls __pm_relax(), it is
 679          * possible that __pm_stay_awake() will be called in the meantime and
 680          * will set ws->active.  Then, ws->active may be cleared immediately
 681          * by the __pm_relax() called from the timer function, but in such a
 682          * case ws->relax_count will be different from ws->active_count.
 683          */
 684         if (ws->relax_count != ws->active_count) {
 685                 ws->relax_count--;
 686                 return;
 687         }
 688
 689         ws->active = false;
 690
 691         now = ktime_get();
 692         duration = ktime_sub(now, ws->last_time);
 693         ws->total_time = ktime_add(ws->total_time, duration);
 694         if (ktime_to_ns(duration) > ktime_to_ns(ws->max_time))
 695                 ws->max_time = duration;
 696
 697         ws->last_time = now;
 698         del_timer(&ws->timer);
 699         ws->timer_expires = 0;
 700
 701         if (ws->autosleep_enabled)
 702                 update_prevent_sleep_time(ws, now);
 703
 704         /*
 705          * Increment the counter of registered wakeup events and decrement the
 706          * counter of wakeup events in progress simultaneously.
 707          */
 708         cec = atomic_add_return(MAX_IN_PROGRESS, &combined_event_count);
 709         trace_wakeup_source_deactivate(ws->name, cec);
 710
 711         split_counters(&cnt, &inpr);
 712         if (!inpr && waitqueue_active(&wakeup_count_wait_queue))
 713                 wake_up(&wakeup_count_wait_queue);
 714 }
 715
 716 /**
 717  * __pm_relax - Notify the PM core that processing of a wakeup event has ended.
 718  * @ws: Wakeup source object associated with the source of the event.
 719  *
 720  * Call this function for wakeup events whose processing started with calling
 721  * __pm_stay_awake().
 722  *
 723  * It is safe to call it from interrupt context.
 724  */
 725 void __pm_relax(struct wakeup_source *ws)
 726 {
 727         unsigned long flags;
 728
 729         if (!ws)
 730                 return;
 731
 732         spin_lock_irqsave(&ws->lock, flags);
 733         if (ws->active)
 734                 wakeup_source_deactivate(ws);
 735         spin_unlock_irqrestore(&ws->lock, flags);
 736 }
 737 EXPORT_SYMBOL_GPL(__pm_relax);
 738
 739 /**
 740  * pm_relax - Notify the PM core that processing of a wakeup event has ended.
 741  * @dev: Device that signaled the event.
 742  *
 743  * Execute __pm_relax() for the @dev's wakeup source object.
 744  */
 745 void pm_relax(struct device *dev)
 746 {
 747         unsigned long flags;
 748
 749         if (!dev)
 750                 return;
 751
 752         spin_lock_irqsave(&dev->power.lock, flags);
 753         __pm_relax(dev->power.wakeup);
 754         spin_unlock_irqrestore(&dev->power.lock, flags);
 755 }
 756 EXPORT_SYMBOL_GPL(pm_relax);
 757
 758 /**
 759  * pm_wakeup_timer_fn - Delayed finalization of a wakeup event.
 760  * @t: timer list
 761  *
 762  * Call wakeup_source_deactivate() for the wakeup source whose address is stored
 763  * in @data if it is currently active and its timer has not been canceled and
 764  * the expiration time of the timer is not in future.
 765  */
 766 static void pm_wakeup_timer_fn(struct timer_list *t)
 767 {
 768         struct wakeup_source *ws = from_timer(ws, t, timer);
 769         unsigned long flags;
 770
 771         spin_lock_irqsave(&ws->lock, flags);
 772
 773         if (ws->active && ws->timer_expires
 774             && time_after_eq(jiffies, ws->timer_expires)) {
 775                 wakeup_source_deactivate(ws);
 776                 ws->expire_count++;
 777         }
 778
 779         spin_unlock_irqrestore(&ws->lock, flags);
 780 }
 781
 782 /**
 783  * pm_wakeup_ws_event - Notify the PM core of a wakeup event.
 784  * @ws: Wakeup source object associated with the event source.
 785  * @msec: Anticipated event processing time (in milliseconds).
 786  * @hard: If set, abort suspends in progress and wake up from suspend-to-idle.
 787  *
 788  * Notify the PM core of a wakeup event whose source is @ws that will take
 789  * approximately @msec milliseconds to be processed by the kernel.  If @ws is
 790  * not active, activate it.  If @msec is nonzero, set up the @ws' timer to
 791  * execute pm_wakeup_timer_fn() in future.
 792  *
 793  * It is safe to call this function from interrupt context.
 794  */
 795 void pm_wakeup_ws_event(struct wakeup_source *ws, unsigned int msec, bool hard)
 796 {
 797         unsigned long flags;
 798         unsigned long expires;
 799
 800         if (!ws)
 801                 return;
 802
 803         spin_lock_irqsave(&ws->lock, flags);
 804
 805         wakeup_source_report_event(ws, hard);
 806
 807         if (!msec) {
 808                 wakeup_source_deactivate(ws);
 809                 goto unlock;
 810         }
 811
 812         expires = jiffies + msecs_to_jiffies(msec);
 813         if (!expires)
 814                 expires = 1;
 815
 816         if (!ws->timer_expires || time_after(expires, ws->timer_expires)) {
 817                 mod_timer(&ws->timer, expires);
 818                 ws->timer_expires = expires;
 819         }
 820
 821  unlock:
 822         spin_unlock_irqrestore(&ws->lock, flags);
 823 }
 824 EXPORT_SYMBOL_GPL(pm_wakeup_ws_event);
 825
 826 /**
 827  * pm_wakeup_dev_event - Notify the PM core of a wakeup event.
 828  * @dev: Device the wakeup event is related to.
 829  * @msec: Anticipated event processing time (in milliseconds).
 830  * @hard: If set, abort suspends in progress and wake up from suspend-to-idle.
 831  *
 832  * Call pm_wakeup_ws_event() for the @dev's wakeup source object.
 833  */
 834 void pm_wakeup_dev_event(struct device *dev, unsigned int msec, bool hard)
 835 {
 836         unsigned long flags;
 837
 838         if (!dev)
 839                 return;
 840
 841         spin_lock_irqsave(&dev->power.lock, flags);
 842         pm_wakeup_ws_event(dev->power.wakeup, msec, hard);
 843         spin_unlock_irqrestore(&dev->power.lock, flags);
 844 }
 845 EXPORT_SYMBOL_GPL(pm_wakeup_dev_event);
 846
 847 void pm_print_active_wakeup_sources(void)
 848 {
 849         struct wakeup_source *ws;
 850         int srcuidx, active = 0;
 851         struct wakeup_source *last_activity_ws = NULL;
 852
 853         srcuidx = srcu_read_lock(&wakeup_srcu);
 854         list_for_each_entry_rcu_locked(ws, &wakeup_sources, entry) {
 855                 if (ws->active) {
 856                         pm_pr_dbg("active wakeup source: %s\n", ws->name);
 857                         active = 1;
 858                 } else if (!active &&
 859                            (!last_activity_ws ||
 860                             ktime_to_ns(ws->last_time) >
 861                             ktime_to_ns(last_activity_ws->last_time))) {
 862                         last_activity_ws = ws;
 863                 }
 864         }
 865
 866         if (!active && last_activity_ws)
 867                 pm_pr_dbg("last active wakeup source: %s\n",
 868                         last_activity_ws->name);
 869         srcu_read_unlock(&wakeup_srcu, srcuidx);
 870 }
 871 EXPORT_SYMBOL_GPL(pm_print_active_wakeup_sources);
 872
 873 /**
 874  * pm_wakeup_pending - Check if power transition in progress should be aborted.
 875  *
 876  * Compare the current number of registered wakeup events with its preserved
 877  * value from the past and return true if new wakeup events have been registered
 878  * since the old value was stored.  Also return true if the current number of
 879  * wakeup events being processed is different from zero.
 880  */
 881 bool pm_wakeup_pending(void)
 882 {
 883         unsigned long flags;
 884         bool ret = false;
 885
 886         raw_spin_lock_irqsave(&events_lock, flags);
 887         if (events_check_enabled) {
 888                 unsigned int cnt, inpr;
 889
 890                 split_counters(&cnt, &inpr);
 891                 ret = (cnt != saved_count || inpr > 0);
 892                 events_check_enabled = !ret;
 893         }
 894         raw_spin_unlock_irqrestore(&events_lock, flags);
 895
 896         if (ret) {
 897                 pm_pr_dbg("Wakeup pending, aborting suspend\n");
 898                 pm_print_active_wakeup_sources();
 899         }
 900
 901         return ret || atomic_read(&pm_abort_suspend) > 0;
 902 }
 903 EXPORT_SYMBOL_GPL(pm_wakeup_pending);
 904
 905 void pm_system_wakeup(void)
 906 {
 907         atomic_inc(&pm_abort_suspend);
 908         s2idle_wake();
 909 }
 910 EXPORT_SYMBOL_GPL(pm_system_wakeup);
 911
 912 void pm_system_cancel_wakeup(void)
 913 {
 914         atomic_dec_if_positive(&pm_abort_suspend);
 915 }
 916
 917 void pm_wakeup_clear(unsigned int irq_number)
 918 {
 919         raw_spin_lock_irq(&wakeup_irq_lock);
 920
 921         if (irq_number && wakeup_irq[0] == irq_number)
 922                 wakeup_irq[0] = wakeup_irq[1];
 923         else
 924                 wakeup_irq[0] = 0;
 925
 926         wakeup_irq[1] = 0;
 927
 928         raw_spin_unlock_irq(&wakeup_irq_lock);
 929
 930         if (!irq_number)
 931                 atomic_set(&pm_abort_suspend, 0);
 932 }
 933
 934 void pm_system_irq_wakeup(unsigned int irq_number)
 935 {
 936         unsigned long flags;
 937
 938         raw_spin_lock_irqsave(&wakeup_irq_lock, flags);
 939
 940         if (wakeup_irq[0] == 0)
 941                 wakeup_irq[0] = irq_number;
 942         else if (wakeup_irq[1] == 0)
 943                 wakeup_irq[1] = irq_number;
 944         else
 945                 irq_number = 0;
 946
 947         raw_spin_unlock_irqrestore(&wakeup_irq_lock, flags);
 948
 949         if (irq_number)
 950                 pm_system_wakeup();
 951 }
 952
 953 unsigned int pm_wakeup_irq(void)
 954 {
 955         return wakeup_irq[0];
 956 }
 957
 958 /**
 959  * pm_get_wakeup_count - Read the number of registered wakeup events.
 960  * @count: Address to store the value at.
 961  * @block: Whether or not to block.
 962  *
 963  * Store the number of registered wakeup events at the address in @count.  If
 964  * @block is set, block until the current number of wakeup events being
 965  * processed is zero.
 966  *
 967  * Return 'false' if the current number of wakeup events being processed is
 968  * nonzero.  Otherwise return 'true'.
 969  */
 970 bool pm_get_wakeup_count(unsigned int *count, bool block)
 971 {
 972         unsigned int cnt, inpr;
 973
 974         if (block) {
 975                 DEFINE_WAIT(wait);
 976
 977                 for (;;) {
 978                         prepare_to_wait(&wakeup_count_wait_queue, &wait,
 979                                         TASK_INTERRUPTIBLE);
 980                         split_counters(&cnt, &inpr);
 981                         if (inpr == 0 || signal_pending(current))
 982                                 break;
 983                         pm_print_active_wakeup_sources();
 984                         schedule();
 985                 }
 986                 finish_wait(&wakeup_count_wait_queue, &wait);
 987         }
 988
 989         split_counters(&cnt, &inpr);
 990         *count = cnt;
 991         return !inpr;
 992 }
 993
 994 /**
 995  * pm_save_wakeup_count - Save the current number of registered wakeup events.
 996  * @count: Value to compare with the current number of registered wakeup events.
 997  *
 998  * If @count is equal to the current number of registered wakeup events and the
 999  * current number of wakeup events being processed is zero, store @count as the
1000  * old number of registered wakeup events for pm_check_wakeup_events(), enable
1001  * wakeup events detection and return 'true'.  Otherwise disable wakeup events
1002  * detection and return 'false'.
1003  */
1004 bool pm_save_wakeup_count(unsigned int count)
1005 {
1006         unsigned int cnt, inpr;
1007         unsigned long flags;
1008
1009         events_check_enabled = false;
1010         raw_spin_lock_irqsave(&events_lock, flags);
1011         split_counters(&cnt, &inpr);
1012         if (cnt == count && inpr == 0) {
1013                 saved_count = count;
1014                 events_check_enabled = true;
1015         }
1016         raw_spin_unlock_irqrestore(&events_lock, flags);
1017         return events_check_enabled;
1018 }
1019
1020 #ifdef CONFIG_PM_AUTOSLEEP
1021 /**
1022  * pm_wakep_autosleep_enabled - Modify autosleep_enabled for all wakeup sources.
1023  * @set: Whether to set or to clear the autosleep_enabled flags.
1024  */
1025 void pm_wakep_autosleep_enabled(bool set)
1026 {
1027         struct wakeup_source *ws;
1028         ktime_t now = ktime_get();
1029         int srcuidx;
1030
1031         srcuidx = srcu_read_lock(&wakeup_srcu);
1032         list_for_each_entry_rcu_locked(ws, &wakeup_sources, entry) {
1033                 spin_lock_irq(&ws->lock);
1034                 if (ws->autosleep_enabled != set) {
1035                         ws->autosleep_enabled = set;
1036                         if (ws->active) {
1037                                 if (set)
1038                                         ws->start_prevent_time = now;
1039                                 else
1040                                         update_prevent_sleep_time(ws, now);
1041                         }
1042                 }
1043                 spin_unlock_irq(&ws->lock);
1044         }
1045         srcu_read_unlock(&wakeup_srcu, srcuidx);
1046 }
1047 #endif /* CONFIG_PM_AUTOSLEEP */
1048
1049 /**
1050  * print_wakeup_source_stats - Print wakeup source statistics information.
1051  * @m: seq_file to print the statistics into.
1052  * @ws: Wakeup source object to print the statistics for.
1053  */
1054 static int print_wakeup_source_stats(struct seq_file *m,
1055                                      struct wakeup_source *ws)
1056 {
1057         unsigned long flags;
1058         ktime_t total_time;
1059         ktime_t max_time;
1060         unsigned long active_count;
1061         ktime_t active_time;
1062         ktime_t prevent_sleep_time;
1063
1064         spin_lock_irqsave(&ws->lock, flags);
1065
1066         total_time = ws->total_time;
1067         max_time = ws->max_time;
1068         prevent_sleep_time = ws->prevent_sleep_time;
1069         active_count = ws->active_count;
1070         if (ws->active) {
1071                 ktime_t now = ktime_get();
1072
1073                 active_time = ktime_sub(now, ws->last_time);
1074                 total_time = ktime_add(total_time, active_time);
1075                 if (active_time > max_time)
1076                         max_time = active_time;
1077
1078                 if (ws->autosleep_enabled)
1079                         prevent_sleep_time = ktime_add(prevent_sleep_time,
1080                                 ktime_sub(now, ws->start_prevent_time));
1081         } else {
1082                 active_time = 0;
1083         }
1084
1085         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",
1086                    ws->name, active_count, ws->event_count,
1087                    ws->wakeup_count, ws->expire_count,
1088                    ktime_to_ms(active_time), ktime_to_ms(total_time),
1089                    ktime_to_ms(max_time), ktime_to_ms(ws->last_time),
1090                    ktime_to_ms(prevent_sleep_time));
1091
1092         spin_unlock_irqrestore(&ws->lock, flags);
1093
1094         return 0;
1095 }
1096
1097 static void *wakeup_sources_stats_seq_start(struct seq_file *m,
1098                                         loff_t *pos)
1099 {
1100         struct wakeup_source *ws;
1101         loff_t n = *pos;
1102         int *srcuidx = m->private;
1103
1104         if (n == 0) {
1105                 seq_puts(m, "name\t\tactive_count\tevent_count\twakeup_count\t"
1106                         "expire_count\tactive_since\ttotal_time\tmax_time\t"
1107                         "last_change\tprevent_suspend_time\n");
1108         }
1109
1110         *srcuidx = srcu_read_lock(&wakeup_srcu);
1111         list_for_each_entry_rcu_locked(ws, &wakeup_sources, entry) {
1112                 if (n-- <= 0)
1113                         return ws;
1114         }
1115
1116         return NULL;
1117 }
1118
1119 static void *wakeup_sources_stats_seq_next(struct seq_file *m,
1120                                         void *v, loff_t *pos)
1121 {
1122         struct wakeup_source *ws = v;
1123         struct wakeup_source *next_ws = NULL;
1124
1125         ++(*pos);
1126
1127         list_for_each_entry_continue_rcu(ws, &wakeup_sources, entry) {
1128                 next_ws = ws;
1129                 break;
1130         }
1131
1132         if (!next_ws)
1133                 print_wakeup_source_stats(m, &deleted_ws);
1134
1135         return next_ws;
1136 }
1137
1138 static void wakeup_sources_stats_seq_stop(struct seq_file *m, void *v)
1139 {
1140         int *srcuidx = m->private;
1141
1142         srcu_read_unlock(&wakeup_srcu, *srcuidx);
1143 }
1144
1145 /**
1146  * wakeup_sources_stats_seq_show - Print wakeup sources statistics information.
1147  * @m: seq_file to print the statistics into.
1148  * @v: wakeup_source of each iteration
1149  */
1150 static int wakeup_sources_stats_seq_show(struct seq_file *m, void *v)
1151 {
1152         struct wakeup_source *ws = v;
1153
1154         print_wakeup_source_stats(m, ws);
1155
1156         return 0;
1157 }
1158
1159 static const struct seq_operations wakeup_sources_stats_seq_ops = {
1160         .start = wakeup_sources_stats_seq_start,
1161         .next  = wakeup_sources_stats_seq_next,
1162         .stop  = wakeup_sources_stats_seq_stop,
1163         .show  = wakeup_sources_stats_seq_show,
1164 };
1165
1166 static int wakeup_sources_stats_open(struct inode *inode, struct file *file)
1167 {
1168         return seq_open_private(file, &wakeup_sources_stats_seq_ops, sizeof(int));
1169 }
1170
1171 static const struct file_operations wakeup_sources_stats_fops = {
1172         .owner = THIS_MODULE,
1173         .open = wakeup_sources_stats_open,
1174         .read = seq_read,
1175         .llseek = seq_lseek,
1176         .release = seq_release_private,
1177 };
1178
1179 static int __init wakeup_sources_debugfs_init(void)
1180 {
1181         debugfs_create_file("wakeup_sources", 0444, NULL, NULL,
1182                             &wakeup_sources_stats_fops);
1183         return 0;
1184 }
1185
1186 postcore_initcall(wakeup_sources_debugfs_init);