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