drivers/base/power/main.c

   1 /*
   2  * drivers/base/power/main.c - Where the driver meets power management.
   3  *
   4  * Copyright (c) 2003 Patrick Mochel
   5  * Copyright (c) 2003 Open Source Development Lab
   6  *
   7  * This file is released under the GPLv2
   8  *
   9  *
  10  * The driver model core calls device_pm_add() when a device is registered.
  11  * This will initialize the embedded device_pm_info object in the device
  12  * and add it to the list of power-controlled devices. sysfs entries for
  13  * controlling device power management will also be added.
  14  *
  15  * A separate list is used for keeping track of power info, because the power
  16  * domain dependencies may differ from the ancestral dependencies that the
  17  * subsystem list maintains.
  18  */
  19
  20 #include <linux/device.h>
  21 #include <linux/kallsyms.h>
  22 #include <linux/export.h>
  23 #include <linux/mutex.h>
  24 #include <linux/pm.h>
  25 #include <linux/pm_runtime.h>
  26 #include <linux/resume-trace.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/sched.h>
  29 #include <linux/async.h>
  30 #include <linux/suspend.h>
  31 #include <trace/events/power.h>
  32 #include <linux/cpufreq.h>
  33 #include <linux/cpuidle.h>
  34 #include <linux/timer.h>
  35
  36 #include "../base.h"
  37 #include "power.h"
  38
  39 typedef int (*pm_callback_t)(struct device *);
  40
  41 /*
  42  * The entries in the dpm_list list are in a depth first order, simply
  43  * because children are guaranteed to be discovered after parents, and
  44  * are inserted at the back of the list on discovery.
  45  *
  46  * Since device_pm_add() may be called with a device lock held,
  47  * we must never try to acquire a device lock while holding
  48  * dpm_list_mutex.
  49  */
  50
  51 LIST_HEAD(dpm_list);
  52 static LIST_HEAD(dpm_prepared_list);
  53 static LIST_HEAD(dpm_suspended_list);
  54 static LIST_HEAD(dpm_late_early_list);
  55 static LIST_HEAD(dpm_noirq_list);
  56
  57 struct suspend_stats suspend_stats;
  58 static DEFINE_MUTEX(dpm_list_mtx);
  59 static pm_message_t pm_transition;
  60
  61 static int async_error;
  62
  63 static char *pm_verb(int event)
  64 {
  65         switch (event) {
  66         case PM_EVENT_SUSPEND:
  67                 return "suspend";
  68         case PM_EVENT_RESUME:
  69                 return "resume";
  70         case PM_EVENT_FREEZE:
  71                 return "freeze";
  72         case PM_EVENT_QUIESCE:
  73                 return "quiesce";
  74         case PM_EVENT_HIBERNATE:
  75                 return "hibernate";
  76         case PM_EVENT_THAW:
  77                 return "thaw";
  78         case PM_EVENT_RESTORE:
  79                 return "restore";
  80         case PM_EVENT_RECOVER:
  81                 return "recover";
  82         default:
  83                 return "(unknown PM event)";
  84         }
  85 }
  86
  87 /**
  88  * device_pm_sleep_init - Initialize system suspend-related device fields.
  89  * @dev: Device object being initialized.
  90  */
  91 void device_pm_sleep_init(struct device *dev)
  92 {
  93         dev->power.is_prepared = false;
  94         dev->power.is_suspended = false;
  95         init_completion(&dev->power.completion);
  96         complete_all(&dev->power.completion);
  97         dev->power.wakeup = NULL;
  98         INIT_LIST_HEAD(&dev->power.entry);
  99 }
 100
 101 /**
 102  * device_pm_lock - Lock the list of active devices used by the PM core.
 103  */
 104 void device_pm_lock(void)
 105 {
 106         mutex_lock(&dpm_list_mtx);
 107 }
 108
 109 /**
 110  * device_pm_unlock - Unlock the list of active devices used by the PM core.
 111  */
 112 void device_pm_unlock(void)
 113 {
 114         mutex_unlock(&dpm_list_mtx);
 115 }
 116
 117 /**
 118  * device_pm_add - Add a device to the PM core's list of active devices.
 119  * @dev: Device to add to the list.
 120  */
 121 void device_pm_add(struct device *dev)
 122 {
 123         pr_debug("PM: Adding info for %s:%s\n",
 124                  dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
 125         mutex_lock(&dpm_list_mtx);
 126         if (dev->parent && dev->parent->power.is_prepared)
 127                 dev_warn(dev, "parent %s should not be sleeping\n",
 128                         dev_name(dev->parent));
 129         list_add_tail(&dev->power.entry, &dpm_list);
 130         mutex_unlock(&dpm_list_mtx);
 131 }
 132
 133 /**
 134  * device_pm_remove - Remove a device from the PM core's list of active devices.
 135  * @dev: Device to be removed from the list.
 136  */
 137 void device_pm_remove(struct device *dev)
 138 {
 139         pr_debug("PM: Removing info for %s:%s\n",
 140                  dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
 141         complete_all(&dev->power.completion);
 142         mutex_lock(&dpm_list_mtx);
 143         list_del_init(&dev->power.entry);
 144         mutex_unlock(&dpm_list_mtx);
 145         device_wakeup_disable(dev);
 146         pm_runtime_remove(dev);
 147 }
 148
 149 /**
 150  * device_pm_move_before - Move device in the PM core's list of active devices.
 151  * @deva: Device to move in dpm_list.
 152  * @devb: Device @deva should come before.
 153  */
 154 void device_pm_move_before(struct device *deva, struct device *devb)
 155 {
 156         pr_debug("PM: Moving %s:%s before %s:%s\n",
 157                  deva->bus ? deva->bus->name : "No Bus", dev_name(deva),
 158                  devb->bus ? devb->bus->name : "No Bus", dev_name(devb));
 159         /* Delete deva from dpm_list and reinsert before devb. */
 160         list_move_tail(&deva->power.entry, &devb->power.entry);
 161 }
 162
 163 /**
 164  * device_pm_move_after - Move device in the PM core's list of active devices.
 165  * @deva: Device to move in dpm_list.
 166  * @devb: Device @deva should come after.
 167  */
 168 void device_pm_move_after(struct device *deva, struct device *devb)
 169 {
 170         pr_debug("PM: Moving %s:%s after %s:%s\n",
 171                  deva->bus ? deva->bus->name : "No Bus", dev_name(deva),
 172                  devb->bus ? devb->bus->name : "No Bus", dev_name(devb));
 173         /* Delete deva from dpm_list and reinsert after devb. */
 174         list_move(&deva->power.entry, &devb->power.entry);
 175 }
 176
 177 /**
 178  * device_pm_move_last - Move device to end of the PM core's list of devices.
 179  * @dev: Device to move in dpm_list.
 180  */
 181 void device_pm_move_last(struct device *dev)
 182 {
 183         pr_debug("PM: Moving %s:%s to end of list\n",
 184                  dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
 185         list_move_tail(&dev->power.entry, &dpm_list);
 186 }
 187
 188 static ktime_t initcall_debug_start(struct device *dev)
 189 {
 190         ktime_t calltime = ktime_set(0, 0);
 191
 192         if (pm_print_times_enabled) {
 193                 pr_info("calling  %s+ @ %i, parent: %s\n",
 194                         dev_name(dev), task_pid_nr(current),
 195                         dev->parent ? dev_name(dev->parent) : "none");
 196                 calltime = ktime_get();
 197         }
 198
 199         return calltime;
 200 }
 201
 202 static void initcall_debug_report(struct device *dev, ktime_t calltime,
 203                                   int error, pm_message_t state, char *info)
 204 {
 205         ktime_t rettime;
 206         s64 nsecs;
 207
 208         rettime = ktime_get();
 209         nsecs = (s64) ktime_to_ns(ktime_sub(rettime, calltime));
 210
 211         if (pm_print_times_enabled) {
 212                 pr_info("call %s+ returned %d after %Ld usecs\n", dev_name(dev),
 213                         error, (unsigned long long)nsecs >> 10);
 214         }
 215
 216         trace_device_pm_report_time(dev, info, nsecs, pm_verb(state.event),
 217                                     error);
 218 }
 219
 220 /**
 221  * dpm_wait - Wait for a PM operation to complete.
 222  * @dev: Device to wait for.
 223  * @async: If unset, wait only if the device's power.async_suspend flag is set.
 224  */
 225 static void dpm_wait(struct device *dev, bool async)
 226 {
 227         if (!dev)
 228                 return;
 229
 230         if (async || (pm_async_enabled && dev->power.async_suspend))
 231                 wait_for_completion(&dev->power.completion);
 232 }
 233
 234 static int dpm_wait_fn(struct device *dev, void *async_ptr)
 235 {
 236         dpm_wait(dev, *((bool *)async_ptr));
 237         return 0;
 238 }
 239
 240 static void dpm_wait_for_children(struct device *dev, bool async)
 241 {
 242        device_for_each_child(dev, &async, dpm_wait_fn);
 243 }
 244
 245 /**
 246  * pm_op - Return the PM operation appropriate for given PM event.
 247  * @ops: PM operations to choose from.
 248  * @state: PM transition of the system being carried out.
 249  */
 250 static pm_callback_t pm_op(const struct dev_pm_ops *ops, pm_message_t state)
 251 {
 252         switch (state.event) {
 253 #ifdef CONFIG_SUSPEND
 254         case PM_EVENT_SUSPEND:
 255                 return ops->suspend;
 256         case PM_EVENT_RESUME:
 257                 return ops->resume;
 258 #endif /* CONFIG_SUSPEND */
 259 #ifdef CONFIG_HIBERNATE_CALLBACKS
 260         case PM_EVENT_FREEZE:
 261         case PM_EVENT_QUIESCE:
 262                 return ops->freeze;
 263         case PM_EVENT_HIBERNATE:
 264                 return ops->poweroff;
 265         case PM_EVENT_THAW:
 266         case PM_EVENT_RECOVER:
 267                 return ops->thaw;
 268                 break;
 269         case PM_EVENT_RESTORE:
 270                 return ops->restore;
 271 #endif /* CONFIG_HIBERNATE_CALLBACKS */
 272         }
 273
 274         return NULL;
 275 }
 276
 277 /**
 278  * pm_late_early_op - Return the PM operation appropriate for given PM event.
 279  * @ops: PM operations to choose from.
 280  * @state: PM transition of the system being carried out.
 281  *
 282  * Runtime PM is disabled for @dev while this function is being executed.
 283  */
 284 static pm_callback_t pm_late_early_op(const struct dev_pm_ops *ops,
 285                                       pm_message_t state)
 286 {
 287         switch (state.event) {
 288 #ifdef CONFIG_SUSPEND
 289         case PM_EVENT_SUSPEND:
 290                 return ops->suspend_late;
 291         case PM_EVENT_RESUME:
 292                 return ops->resume_early;
 293 #endif /* CONFIG_SUSPEND */
 294 #ifdef CONFIG_HIBERNATE_CALLBACKS
 295         case PM_EVENT_FREEZE:
 296         case PM_EVENT_QUIESCE:
 297                 return ops->freeze_late;
 298         case PM_EVENT_HIBERNATE:
 299                 return ops->poweroff_late;
 300         case PM_EVENT_THAW:
 301         case PM_EVENT_RECOVER:
 302                 return ops->thaw_early;
 303         case PM_EVENT_RESTORE:
 304                 return ops->restore_early;
 305 #endif /* CONFIG_HIBERNATE_CALLBACKS */
 306         }
 307
 308         return NULL;
 309 }
 310
 311 /**
 312  * pm_noirq_op - Return the PM operation appropriate for given PM event.
 313  * @ops: PM operations to choose from.
 314  * @state: PM transition of the system being carried out.
 315  *
 316  * The driver of @dev will not receive interrupts while this function is being
 317  * executed.
 318  */
 319 static pm_callback_t pm_noirq_op(const struct dev_pm_ops *ops, pm_message_t state)
 320 {
 321         switch (state.event) {
 322 #ifdef CONFIG_SUSPEND
 323         case PM_EVENT_SUSPEND:
 324                 return ops->suspend_noirq;
 325         case PM_EVENT_RESUME:
 326                 return ops->resume_noirq;
 327 #endif /* CONFIG_SUSPEND */
 328 #ifdef CONFIG_HIBERNATE_CALLBACKS
 329         case PM_EVENT_FREEZE:
 330         case PM_EVENT_QUIESCE:
 331                 return ops->freeze_noirq;
 332         case PM_EVENT_HIBERNATE:
 333                 return ops->poweroff_noirq;
 334         case PM_EVENT_THAW:
 335         case PM_EVENT_RECOVER:
 336                 return ops->thaw_noirq;
 337         case PM_EVENT_RESTORE:
 338                 return ops->restore_noirq;
 339 #endif /* CONFIG_HIBERNATE_CALLBACKS */
 340         }
 341
 342         return NULL;
 343 }
 344
 345 static void pm_dev_dbg(struct device *dev, pm_message_t state, char *info)
 346 {
 347         dev_dbg(dev, "%s%s%s\n", info, pm_verb(state.event),
 348                 ((state.event & PM_EVENT_SLEEP) && device_may_wakeup(dev)) ?
 349                 ", may wakeup" : "");
 350 }
 351
 352 static void pm_dev_err(struct device *dev, pm_message_t state, char *info,
 353                         int error)
 354 {
 355         printk(KERN_ERR "PM: Device %s failed to %s%s: error %d\n",
 356                 dev_name(dev), pm_verb(state.event), info, error);
 357 }
 358
 359 static void dpm_show_time(ktime_t starttime, pm_message_t state, char *info)
 360 {
 361         ktime_t calltime;
 362         u64 usecs64;
 363         int usecs;
 364
 365         calltime = ktime_get();
 366         usecs64 = ktime_to_ns(ktime_sub(calltime, starttime));
 367         do_div(usecs64, NSEC_PER_USEC);
 368         usecs = usecs64;
 369         if (usecs == 0)
 370                 usecs = 1;
 371         pr_info("PM: %s%s%s of devices complete after %ld.%03ld msecs\n",
 372                 info ?: "", info ? " " : "", pm_verb(state.event),
 373                 usecs / USEC_PER_MSEC, usecs % USEC_PER_MSEC);
 374 }
 375
 376 static int dpm_run_callback(pm_callback_t cb, struct device *dev,
 377                             pm_message_t state, char *info)
 378 {
 379         ktime_t calltime;
 380         int error;
 381
 382         if (!cb)
 383                 return 0;
 384
 385         calltime = initcall_debug_start(dev);
 386
 387         pm_dev_dbg(dev, state, info);
 388         error = cb(dev);
 389         suspend_report_result(cb, error);
 390
 391         initcall_debug_report(dev, calltime, error, state, info);
 392
 393         return error;
 394 }
 395
 396 #ifdef CONFIG_DPM_WATCHDOG
 397 struct dpm_watchdog {
 398         struct device           *dev;
 399         struct task_struct      *tsk;
 400         struct timer_list       timer;
 401 };
 402
 403 #define DECLARE_DPM_WATCHDOG_ON_STACK(wd) \
 404         struct dpm_watchdog wd
 405
 406 /**
 407  * dpm_watchdog_handler - Driver suspend / resume watchdog handler.
 408  * @data: Watchdog object address.
 409  *
 410  * Called when a driver has timed out suspending or resuming.
 411  * There's not much we can do here to recover so panic() to
 412  * capture a crash-dump in pstore.
 413  */
 414 static void dpm_watchdog_handler(unsigned long data)
 415 {
 416         struct dpm_watchdog *wd = (void *)data;
 417
 418         dev_emerg(wd->dev, "**** DPM device timeout ****\n");
 419         show_stack(wd->tsk, NULL);
 420         panic("%s %s: unrecoverable failure\n",
 421                 dev_driver_string(wd->dev), dev_name(wd->dev));
 422 }
 423
 424 /**
 425  * dpm_watchdog_set - Enable pm watchdog for given device.
 426  * @wd: Watchdog. Must be allocated on the stack.
 427  * @dev: Device to handle.
 428  */
 429 static void dpm_watchdog_set(struct dpm_watchdog *wd, struct device *dev)
 430 {
 431         struct timer_list *timer = &wd->timer;
 432
 433         wd->dev = dev;
 434         wd->tsk = current;
 435
 436         init_timer_on_stack(timer);
 437         /* use same timeout value for both suspend and resume */
 438         timer->expires = jiffies + HZ * CONFIG_DPM_WATCHDOG_TIMEOUT;
 439         timer->function = dpm_watchdog_handler;
 440         timer->data = (unsigned long)wd;
 441         add_timer(timer);
 442 }
 443
 444 /**
 445  * dpm_watchdog_clear - Disable suspend/resume watchdog.
 446  * @wd: Watchdog to disable.
 447  */
 448 static void dpm_watchdog_clear(struct dpm_watchdog *wd)
 449 {
 450         struct timer_list *timer = &wd->timer;
 451
 452         del_timer_sync(timer);
 453         destroy_timer_on_stack(timer);
 454 }
 455 #else
 456 #define DECLARE_DPM_WATCHDOG_ON_STACK(wd)
 457 #define dpm_watchdog_set(x, y)
 458 #define dpm_watchdog_clear(x)
 459 #endif
 460
 461 /*------------------------- Resume routines -------------------------*/
 462
 463 /**
 464  * device_resume_noirq - Execute an "early resume" callback for given device.
 465  * @dev: Device to handle.
 466  * @state: PM transition of the system being carried out.
 467  *
 468  * The driver of @dev will not receive interrupts while this function is being
 469  * executed.
 470  */
 471 static int device_resume_noirq(struct device *dev, pm_message_t state)
 472 {
 473         pm_callback_t callback = NULL;
 474         char *info = NULL;
 475         int error = 0;
 476
 477         TRACE_DEVICE(dev);
 478         TRACE_RESUME(0);
 479
 480         if (dev->power.syscore)
 481                 goto Out;
 482
 483         if (dev->pm_domain) {
 484                 info = "noirq power domain ";
 485                 callback = pm_noirq_op(&dev->pm_domain->ops, state);
 486         } else if (dev->type && dev->type->pm) {
 487                 info = "noirq type ";
 488                 callback = pm_noirq_op(dev->type->pm, state);
 489         } else if (dev->class && dev->class->pm) {
 490                 info = "noirq class ";
 491                 callback = pm_noirq_op(dev->class->pm, state);
 492         } else if (dev->bus && dev->bus->pm) {
 493                 info = "noirq bus ";
 494                 callback = pm_noirq_op(dev->bus->pm, state);
 495         }
 496
 497         if (!callback && dev->driver && dev->driver->pm) {
 498                 info = "noirq driver ";
 499                 callback = pm_noirq_op(dev->driver->pm, state);
 500         }
 501
 502         error = dpm_run_callback(callback, dev, state, info);
 503
 504  Out:
 505         TRACE_RESUME(error);
 506         return error;
 507 }
 508
 509 /**
 510  * dpm_resume_noirq - Execute "noirq resume" callbacks for all devices.
 511  * @state: PM transition of the system being carried out.
 512  *
 513  * Call the "noirq" resume handlers for all devices in dpm_noirq_list and
 514  * enable device drivers to receive interrupts.
 515  */
 516 static void dpm_resume_noirq(pm_message_t state)
 517 {
 518         ktime_t starttime = ktime_get();
 519
 520         mutex_lock(&dpm_list_mtx);
 521         while (!list_empty(&dpm_noirq_list)) {
 522                 struct device *dev = to_device(dpm_noirq_list.next);
 523                 int error;
 524
 525                 get_device(dev);
 526                 list_move_tail(&dev->power.entry, &dpm_late_early_list);
 527                 mutex_unlock(&dpm_list_mtx);
 528
 529                 error = device_resume_noirq(dev, state);
 530                 if (error) {
 531                         suspend_stats.failed_resume_noirq++;
 532                         dpm_save_failed_step(SUSPEND_RESUME_NOIRQ);
 533                         dpm_save_failed_dev(dev_name(dev));
 534                         pm_dev_err(dev, state, " noirq", error);
 535                 }
 536
 537                 mutex_lock(&dpm_list_mtx);
 538                 put_device(dev);
 539         }
 540         mutex_unlock(&dpm_list_mtx);
 541         dpm_show_time(starttime, state, "noirq");
 542         resume_device_irqs();
 543         cpuidle_resume();
 544         cpufreq_resume();
 545 }
 546
 547 /**
 548  * device_resume_early - Execute an "early resume" callback for given device.
 549  * @dev: Device to handle.
 550  * @state: PM transition of the system being carried out.
 551  *
 552  * Runtime PM is disabled for @dev while this function is being executed.
 553  */
 554 static int device_resume_early(struct device *dev, pm_message_t state)
 555 {
 556         pm_callback_t callback = NULL;
 557         char *info = NULL;
 558         int error = 0;
 559
 560         TRACE_DEVICE(dev);
 561         TRACE_RESUME(0);
 562
 563         if (dev->power.syscore)
 564                 goto Out;
 565
 566         if (dev->pm_domain) {
 567                 info = "early power domain ";
 568                 callback = pm_late_early_op(&dev->pm_domain->ops, state);
 569         } else if (dev->type && dev->type->pm) {
 570                 info = "early type ";
 571                 callback = pm_late_early_op(dev->type->pm, state);
 572         } else if (dev->class && dev->class->pm) {
 573                 info = "early class ";
 574                 callback = pm_late_early_op(dev->class->pm, state);
 575         } else if (dev->bus && dev->bus->pm) {
 576                 info = "early bus ";
 577                 callback = pm_late_early_op(dev->bus->pm, state);
 578         }
 579
 580         if (!callback && dev->driver && dev->driver->pm) {
 581                 info = "early driver ";
 582                 callback = pm_late_early_op(dev->driver->pm, state);
 583         }
 584
 585         error = dpm_run_callback(callback, dev, state, info);
 586
 587  Out:
 588         TRACE_RESUME(error);
 589
 590         pm_runtime_enable(dev);
 591         return error;
 592 }
 593
 594 /**
 595  * dpm_resume_early - Execute "early resume" callbacks for all devices.
 596  * @state: PM transition of the system being carried out.
 597  */
 598 static void dpm_resume_early(pm_message_t state)
 599 {
 600         ktime_t starttime = ktime_get();
 601
 602         mutex_lock(&dpm_list_mtx);
 603         while (!list_empty(&dpm_late_early_list)) {
 604                 struct device *dev = to_device(dpm_late_early_list.next);
 605                 int error;
 606
 607                 get_device(dev);
 608                 list_move_tail(&dev->power.entry, &dpm_suspended_list);
 609                 mutex_unlock(&dpm_list_mtx);
 610
 611                 error = device_resume_early(dev, state);
 612                 if (error) {
 613                         suspend_stats.failed_resume_early++;
 614                         dpm_save_failed_step(SUSPEND_RESUME_EARLY);
 615                         dpm_save_failed_dev(dev_name(dev));
 616                         pm_dev_err(dev, state, " early", error);
 617                 }
 618
 619                 mutex_lock(&dpm_list_mtx);
 620                 put_device(dev);
 621         }
 622         mutex_unlock(&dpm_list_mtx);
 623         dpm_show_time(starttime, state, "early");
 624 }
 625
 626 /**
 627  * dpm_resume_start - Execute "noirq" and "early" device callbacks.
 628  * @state: PM transition of the system being carried out.
 629  */
 630 void dpm_resume_start(pm_message_t state)
 631 {
 632         dpm_resume_noirq(state);
 633         dpm_resume_early(state);
 634 }
 635 EXPORT_SYMBOL_GPL(dpm_resume_start);
 636
 637 /**
 638  * device_resume - Execute "resume" callbacks for given device.
 639  * @dev: Device to handle.
 640  * @state: PM transition of the system being carried out.
 641  * @async: If true, the device is being resumed asynchronously.
 642  */
 643 static int device_resume(struct device *dev, pm_message_t state, bool async)
 644 {
 645         pm_callback_t callback = NULL;
 646         char *info = NULL;
 647         int error = 0;
 648         DECLARE_DPM_WATCHDOG_ON_STACK(wd);
 649
 650         TRACE_DEVICE(dev);
 651         TRACE_RESUME(0);
 652
 653         if (dev->power.syscore)
 654                 goto Complete;
 655
 656         dpm_wait(dev->parent, async);
 657         dpm_watchdog_set(&wd, dev);
 658         device_lock(dev);
 659
 660         /*
 661          * This is a fib.  But we'll allow new children to be added below
 662          * a resumed device, even if the device hasn't been completed yet.
 663          */
 664         dev->power.is_prepared = false;
 665
 666         if (!dev->power.is_suspended)
 667                 goto Unlock;
 668
 669         if (dev->pm_domain) {
 670                 info = "power domain ";
 671                 callback = pm_op(&dev->pm_domain->ops, state);
 672                 goto Driver;
 673         }
 674
 675         if (dev->type && dev->type->pm) {
 676                 info = "type ";
 677                 callback = pm_op(dev->type->pm, state);
 678                 goto Driver;
 679         }
 680
 681         if (dev->class) {
 682                 if (dev->class->pm) {
 683                         info = "class ";
 684                         callback = pm_op(dev->class->pm, state);
 685                         goto Driver;
 686                 } else if (dev->class->resume) {
 687                         info = "legacy class ";
 688                         callback = dev->class->resume;
 689                         goto End;
 690                 }
 691         }
 692
 693         if (dev->bus) {
 694                 if (dev->bus->pm) {
 695                         info = "bus ";
 696                         callback = pm_op(dev->bus->pm, state);
 697                 } else if (dev->bus->resume) {
 698                         info = "legacy bus ";
 699                         callback = dev->bus->resume;
 700                         goto End;
 701                 }
 702         }
 703
 704  Driver:
 705         if (!callback && dev->driver && dev->driver->pm) {
 706                 info = "driver ";
 707                 callback = pm_op(dev->driver->pm, state);
 708         }
 709
 710  End:
 711         error = dpm_run_callback(callback, dev, state, info);
 712         dev->power.is_suspended = false;
 713
 714  Unlock:
 715         device_unlock(dev);
 716         dpm_watchdog_clear(&wd);
 717
 718  Complete:
 719         complete_all(&dev->power.completion);
 720
 721         TRACE_RESUME(error);
 722
 723         return error;
 724 }
 725
 726 static void async_resume(void *data, async_cookie_t cookie)
 727 {
 728         struct device *dev = (struct device *)data;
 729         int error;
 730
 731         error = device_resume(dev, pm_transition, true);
 732         if (error)
 733                 pm_dev_err(dev, pm_transition, " async", error);
 734         put_device(dev);
 735 }
 736
 737 static bool is_async(struct device *dev)
 738 {
 739         return dev->power.async_suspend && pm_async_enabled
 740                 && !pm_trace_is_enabled();
 741 }
 742
 743 /**
 744  * dpm_resume - Execute "resume" callbacks for non-sysdev devices.
 745  * @state: PM transition of the system being carried out.
 746  *
 747  * Execute the appropriate "resume" callback for all devices whose status
 748  * indicates that they are suspended.
 749  */
 750 void dpm_resume(pm_message_t state)
 751 {
 752         struct device *dev;
 753         ktime_t starttime = ktime_get();
 754
 755         might_sleep();
 756
 757         mutex_lock(&dpm_list_mtx);
 758         pm_transition = state;
 759         async_error = 0;
 760
 761         list_for_each_entry(dev, &dpm_suspended_list, power.entry) {
 762                 reinit_completion(&dev->power.completion);
 763                 if (is_async(dev)) {
 764                         get_device(dev);
 765                         async_schedule(async_resume, dev);
 766                 }
 767         }
 768
 769         while (!list_empty(&dpm_suspended_list)) {
 770                 dev = to_device(dpm_suspended_list.next);
 771                 get_device(dev);
 772                 if (!is_async(dev)) {
 773                         int error;
 774
 775                         mutex_unlock(&dpm_list_mtx);
 776
 777                         error = device_resume(dev, state, false);
 778                         if (error) {
 779                                 suspend_stats.failed_resume++;
 780                                 dpm_save_failed_step(SUSPEND_RESUME);
 781                                 dpm_save_failed_dev(dev_name(dev));
 782                                 pm_dev_err(dev, state, "", error);
 783                         }
 784
 785                         mutex_lock(&dpm_list_mtx);
 786                 }
 787                 if (!list_empty(&dev->power.entry))
 788                         list_move_tail(&dev->power.entry, &dpm_prepared_list);
 789                 put_device(dev);
 790         }
 791         mutex_unlock(&dpm_list_mtx);
 792         async_synchronize_full();
 793         dpm_show_time(starttime, state, NULL);
 794 }
 795
 796 /**
 797  * device_complete - Complete a PM transition for given device.
 798  * @dev: Device to handle.
 799  * @state: PM transition of the system being carried out.
 800  */
 801 static void device_complete(struct device *dev, pm_message_t state)
 802 {
 803         void (*callback)(struct device *) = NULL;
 804         char *info = NULL;
 805
 806         if (dev->power.syscore)
 807                 return;
 808
 809         device_lock(dev);
 810
 811         if (dev->pm_domain) {
 812                 info = "completing power domain ";
 813                 callback = dev->pm_domain->ops.complete;
 814         } else if (dev->type && dev->type->pm) {
 815                 info = "completing type ";
 816                 callback = dev->type->pm->complete;
 817         } else if (dev->class && dev->class->pm) {
 818                 info = "completing class ";
 819                 callback = dev->class->pm->complete;
 820         } else if (dev->bus && dev->bus->pm) {
 821                 info = "completing bus ";
 822                 callback = dev->bus->pm->complete;
 823         }
 824
 825         if (!callback && dev->driver && dev->driver->pm) {
 826                 info = "completing driver ";
 827                 callback = dev->driver->pm->complete;
 828         }
 829
 830         if (callback) {
 831                 pm_dev_dbg(dev, state, info);
 832                 callback(dev);
 833         }
 834
 835         device_unlock(dev);
 836
 837         pm_runtime_put(dev);
 838 }
 839
 840 /**
 841  * dpm_complete - Complete a PM transition for all non-sysdev devices.
 842  * @state: PM transition of the system being carried out.
 843  *
 844  * Execute the ->complete() callbacks for all devices whose PM status is not
 845  * DPM_ON (this allows new devices to be registered).
 846  */
 847 void dpm_complete(pm_message_t state)
 848 {
 849         struct list_head list;
 850
 851         might_sleep();
 852
 853         INIT_LIST_HEAD(&list);
 854         mutex_lock(&dpm_list_mtx);
 855         while (!list_empty(&dpm_prepared_list)) {
 856                 struct device *dev = to_device(dpm_prepared_list.prev);
 857
 858                 get_device(dev);
 859                 dev->power.is_prepared = false;
 860                 list_move(&dev->power.entry, &list);
 861                 mutex_unlock(&dpm_list_mtx);
 862
 863                 device_complete(dev, state);
 864
 865                 mutex_lock(&dpm_list_mtx);
 866                 put_device(dev);
 867         }
 868         list_splice(&list, &dpm_list);
 869         mutex_unlock(&dpm_list_mtx);
 870 }
 871
 872 /**
 873  * dpm_resume_end - Execute "resume" callbacks and complete system transition.
 874  * @state: PM transition of the system being carried out.
 875  *
 876  * Execute "resume" callbacks for all devices and complete the PM transition of
 877  * the system.
 878  */
 879 void dpm_resume_end(pm_message_t state)
 880 {
 881         dpm_resume(state);
 882         dpm_complete(state);
 883 }
 884 EXPORT_SYMBOL_GPL(dpm_resume_end);
 885
 886
 887 /*------------------------- Suspend routines -------------------------*/
 888
 889 /**
 890  * resume_event - Return a "resume" message for given "suspend" sleep state.
 891  * @sleep_state: PM message representing a sleep state.
 892  *
 893  * Return a PM message representing the resume event corresponding to given
 894  * sleep state.
 895  */
 896 static pm_message_t resume_event(pm_message_t sleep_state)
 897 {
 898         switch (sleep_state.event) {
 899         case PM_EVENT_SUSPEND:
 900                 return PMSG_RESUME;
 901         case PM_EVENT_FREEZE:
 902         case PM_EVENT_QUIESCE:
 903                 return PMSG_RECOVER;
 904         case PM_EVENT_HIBERNATE:
 905                 return PMSG_RESTORE;
 906         }
 907         return PMSG_ON;
 908 }
 909
 910 /**
 911  * device_suspend_noirq - Execute a "late suspend" callback for given device.
 912  * @dev: Device to handle.
 913  * @state: PM transition of the system being carried out.
 914  *
 915  * The driver of @dev will not receive interrupts while this function is being
 916  * executed.
 917  */
 918 static int device_suspend_noirq(struct device *dev, pm_message_t state)
 919 {
 920         pm_callback_t callback = NULL;
 921         char *info = NULL;
 922
 923         if (dev->power.syscore)
 924                 return 0;
 925
 926         if (dev->pm_domain) {
 927                 info = "noirq power domain ";
 928                 callback = pm_noirq_op(&dev->pm_domain->ops, state);
 929         } else if (dev->type && dev->type->pm) {
 930                 info = "noirq type ";
 931                 callback = pm_noirq_op(dev->type->pm, state);
 932         } else if (dev->class && dev->class->pm) {
 933                 info = "noirq class ";
 934                 callback = pm_noirq_op(dev->class->pm, state);
 935         } else if (dev->bus && dev->bus->pm) {
 936                 info = "noirq bus ";
 937                 callback = pm_noirq_op(dev->bus->pm, state);
 938         }
 939
 940         if (!callback && dev->driver && dev->driver->pm) {
 941                 info = "noirq driver ";
 942                 callback = pm_noirq_op(dev->driver->pm, state);
 943         }
 944
 945         return dpm_run_callback(callback, dev, state, info);
 946 }
 947
 948 /**
 949  * dpm_suspend_noirq - Execute "noirq suspend" callbacks for all devices.
 950  * @state: PM transition of the system being carried out.
 951  *
 952  * Prevent device drivers from receiving interrupts and call the "noirq" suspend
 953  * handlers for all non-sysdev devices.
 954  */
 955 static int dpm_suspend_noirq(pm_message_t state)
 956 {
 957         ktime_t starttime = ktime_get();
 958         int error = 0;
 959
 960         cpufreq_suspend();
 961         cpuidle_pause();
 962         suspend_device_irqs();
 963         mutex_lock(&dpm_list_mtx);
 964         while (!list_empty(&dpm_late_early_list)) {
 965                 struct device *dev = to_device(dpm_late_early_list.prev);
 966
 967                 get_device(dev);
 968                 mutex_unlock(&dpm_list_mtx);
 969
 970                 error = device_suspend_noirq(dev, state);
 971
 972                 mutex_lock(&dpm_list_mtx);
 973                 if (error) {
 974                         pm_dev_err(dev, state, " noirq", error);
 975                         suspend_stats.failed_suspend_noirq++;
 976                         dpm_save_failed_step(SUSPEND_SUSPEND_NOIRQ);
 977                         dpm_save_failed_dev(dev_name(dev));
 978                         put_device(dev);
 979                         break;
 980                 }
 981                 if (!list_empty(&dev->power.entry))
 982                         list_move(&dev->power.entry, &dpm_noirq_list);
 983                 put_device(dev);
 984
 985                 if (pm_wakeup_pending()) {
 986                         error = -EBUSY;
 987                         break;
 988                 }
 989         }
 990         mutex_unlock(&dpm_list_mtx);
 991         if (error)
 992                 dpm_resume_noirq(resume_event(state));
 993         else
 994                 dpm_show_time(starttime, state, "noirq");
 995         return error;
 996 }
 997
 998 /**
 999  * device_suspend_late - Execute a "late suspend" callback for given device.
1000  * @dev: Device to handle.
1001  * @state: PM transition of the system being carried out.
1002  *
1003  * Runtime PM is disabled for @dev while this function is being executed.
1004  */
1005 static int device_suspend_late(struct device *dev, pm_message_t state)
1006 {
1007         pm_callback_t callback = NULL;
1008         char *info = NULL;
1009
1010         __pm_runtime_disable(dev, false);
1011
1012         if (dev->power.syscore)
1013                 return 0;
1014
1015         if (dev->pm_domain) {
1016                 info = "late power domain ";
1017                 callback = pm_late_early_op(&dev->pm_domain->ops, state);
1018         } else if (dev->type && dev->type->pm) {
1019                 info = "late type ";
1020                 callback = pm_late_early_op(dev->type->pm, state);
1021         } else if (dev->class && dev->class->pm) {
1022                 info = "late class ";
1023                 callback = pm_late_early_op(dev->class->pm, state);
1024         } else if (dev->bus && dev->bus->pm) {
1025                 info = "late bus ";
1026                 callback = pm_late_early_op(dev->bus->pm, state);
1027         }
1028
1029         if (!callback && dev->driver && dev->driver->pm) {
1030                 info = "late driver ";
1031                 callback = pm_late_early_op(dev->driver->pm, state);
1032         }
1033
1034         return dpm_run_callback(callback, dev, state, info);
1035 }
1036
1037 /**
1038  * dpm_suspend_late - Execute "late suspend" callbacks for all devices.
1039  * @state: PM transition of the system being carried out.
1040  */
1041 static int dpm_suspend_late(pm_message_t state)
1042 {
1043         ktime_t starttime = ktime_get();
1044         int error = 0;
1045
1046         mutex_lock(&dpm_list_mtx);
1047         while (!list_empty(&dpm_suspended_list)) {
1048                 struct device *dev = to_device(dpm_suspended_list.prev);
1049
1050                 get_device(dev);
1051                 mutex_unlock(&dpm_list_mtx);
1052
1053                 error = device_suspend_late(dev, state);
1054
1055                 mutex_lock(&dpm_list_mtx);
1056                 if (error) {
1057                         pm_dev_err(dev, state, " late", error);
1058                         suspend_stats.failed_suspend_late++;
1059                         dpm_save_failed_step(SUSPEND_SUSPEND_LATE);
1060                         dpm_save_failed_dev(dev_name(dev));
1061                         put_device(dev);
1062                         break;
1063                 }
1064                 if (!list_empty(&dev->power.entry))
1065                         list_move(&dev->power.entry, &dpm_late_early_list);
1066                 put_device(dev);
1067
1068                 if (pm_wakeup_pending()) {
1069                         error = -EBUSY;
1070                         break;
1071                 }
1072         }
1073         mutex_unlock(&dpm_list_mtx);
1074         if (error)
1075                 dpm_resume_early(resume_event(state));
1076         else
1077                 dpm_show_time(starttime, state, "late");
1078
1079         return error;
1080 }
1081
1082 /**
1083  * dpm_suspend_end - Execute "late" and "noirq" device suspend callbacks.
1084  * @state: PM transition of the system being carried out.
1085  */
1086 int dpm_suspend_end(pm_message_t state)
1087 {
1088         int error = dpm_suspend_late(state);
1089         if (error)
1090                 return error;
1091
1092         error = dpm_suspend_noirq(state);
1093         if (error) {
1094                 dpm_resume_early(resume_event(state));
1095                 return error;
1096         }
1097
1098         return 0;
1099 }
1100 EXPORT_SYMBOL_GPL(dpm_suspend_end);
1101
1102 /**
1103  * legacy_suspend - Execute a legacy (bus or class) suspend callback for device.
1104  * @dev: Device to suspend.
1105  * @state: PM transition of the system being carried out.
1106  * @cb: Suspend callback to execute.
1107  */
1108 static int legacy_suspend(struct device *dev, pm_message_t state,
1109                           int (*cb)(struct device *dev, pm_message_t state),
1110                           char *info)
1111 {
1112         int error;
1113         ktime_t calltime;
1114
1115         calltime = initcall_debug_start(dev);
1116
1117         error = cb(dev, state);
1118         suspend_report_result(cb, error);
1119
1120         initcall_debug_report(dev, calltime, error, state, info);
1121
1122         return error;
1123 }
1124
1125 /**
1126  * device_suspend - Execute "suspend" callbacks for given device.
1127  * @dev: Device to handle.
1128  * @state: PM transition of the system being carried out.
1129  * @async: If true, the device is being suspended asynchronously.
1130  */
1131 static int __device_suspend(struct device *dev, pm_message_t state, bool async)
1132 {
1133         pm_callback_t callback = NULL;
1134         char *info = NULL;
1135         int error = 0;
1136         DECLARE_DPM_WATCHDOG_ON_STACK(wd);
1137
1138         dpm_wait_for_children(dev, async);
1139
1140         if (async_error)
1141                 goto Complete;
1142
1143         /*
1144          * If a device configured to wake up the system from sleep states
1145          * has been suspended at run time and there's a resume request pending
1146          * for it, this is equivalent to the device signaling wakeup, so the
1147          * system suspend operation should be aborted.
1148          */
1149         if (pm_runtime_barrier(dev) && device_may_wakeup(dev))
1150                 pm_wakeup_event(dev, 0);
1151
1152         if (pm_wakeup_pending()) {
1153                 async_error = -EBUSY;
1154                 goto Complete;
1155         }
1156
1157         if (dev->power.syscore)
1158                 goto Complete;
1159
1160         dpm_watchdog_set(&wd, dev);
1161         device_lock(dev);
1162
1163         if (dev->pm_domain) {
1164                 info = "power domain ";
1165                 callback = pm_op(&dev->pm_domain->ops, state);
1166                 goto Run;
1167         }
1168
1169         if (dev->type && dev->type->pm) {
1170                 info = "type ";
1171                 callback = pm_op(dev->type->pm, state);
1172                 goto Run;
1173         }
1174
1175         if (dev->class) {
1176                 if (dev->class->pm) {
1177                         info = "class ";
1178                         callback = pm_op(dev->class->pm, state);
1179                         goto Run;
1180                 } else if (dev->class->suspend) {
1181                         pm_dev_dbg(dev, state, "legacy class ");
1182                         error = legacy_suspend(dev, state, dev->class->suspend,
1183                                                 "legacy class ");
1184                         goto End;
1185                 }
1186         }
1187
1188         if (dev->bus) {
1189                 if (dev->bus->pm) {
1190                         info = "bus ";
1191                         callback = pm_op(dev->bus->pm, state);
1192                 } else if (dev->bus->suspend) {
1193                         pm_dev_dbg(dev, state, "legacy bus ");
1194                         error = legacy_suspend(dev, state, dev->bus->suspend,
1195                                                 "legacy bus ");
1196                         goto End;
1197                 }
1198         }
1199
1200  Run:
1201         if (!callback && dev->driver && dev->driver->pm) {
1202                 info = "driver ";
1203                 callback = pm_op(dev->driver->pm, state);
1204         }
1205
1206         error = dpm_run_callback(callback, dev, state, info);
1207
1208  End:
1209         if (!error) {
1210                 dev->power.is_suspended = true;
1211                 if (dev->power.wakeup_path
1212                     && dev->parent && !dev->parent->power.ignore_children)
1213                         dev->parent->power.wakeup_path = true;
1214         }
1215
1216         device_unlock(dev);
1217         dpm_watchdog_clear(&wd);
1218
1219  Complete:
1220         complete_all(&dev->power.completion);
1221         if (error)
1222                 async_error = error;
1223
1224         return error;
1225 }
1226
1227 static void async_suspend(void *data, async_cookie_t cookie)
1228 {
1229         struct device *dev = (struct device *)data;
1230         int error;
1231
1232         error = __device_suspend(dev, pm_transition, true);
1233         if (error) {
1234                 dpm_save_failed_dev(dev_name(dev));
1235                 pm_dev_err(dev, pm_transition, " async", error);
1236         }
1237
1238         put_device(dev);
1239 }
1240
1241 static int device_suspend(struct device *dev)
1242 {
1243         reinit_completion(&dev->power.completion);
1244
1245         if (pm_async_enabled && dev->power.async_suspend) {
1246                 get_device(dev);
1247                 async_schedule(async_suspend, dev);
1248                 return 0;
1249         }
1250
1251         return __device_suspend(dev, pm_transition, false);
1252 }
1253
1254 /**
1255  * dpm_suspend - Execute "suspend" callbacks for all non-sysdev devices.
1256  * @state: PM transition of the system being carried out.
1257  */
1258 int dpm_suspend(pm_message_t state)
1259 {
1260         ktime_t starttime = ktime_get();
1261         int error = 0;
1262
1263         might_sleep();
1264
1265         mutex_lock(&dpm_list_mtx);
1266         pm_transition = state;
1267         async_error = 0;
1268         while (!list_empty(&dpm_prepared_list)) {
1269                 struct device *dev = to_device(dpm_prepared_list.prev);
1270
1271                 get_device(dev);
1272                 mutex_unlock(&dpm_list_mtx);
1273
1274                 error = device_suspend(dev);
1275
1276                 mutex_lock(&dpm_list_mtx);
1277                 if (error) {
1278                         pm_dev_err(dev, state, "", error);
1279                         dpm_save_failed_dev(dev_name(dev));
1280                         put_device(dev);
1281                         break;
1282                 }
1283                 if (!list_empty(&dev->power.entry))
1284                         list_move(&dev->power.entry, &dpm_suspended_list);
1285                 put_device(dev);
1286                 if (async_error)
1287                         break;
1288         }
1289         mutex_unlock(&dpm_list_mtx);
1290         async_synchronize_full();
1291         if (!error)
1292                 error = async_error;
1293         if (error) {
1294                 suspend_stats.failed_suspend++;
1295                 dpm_save_failed_step(SUSPEND_SUSPEND);
1296         } else
1297                 dpm_show_time(starttime, state, NULL);
1298         return error;
1299 }
1300
1301 /**
1302  * device_prepare - Prepare a device for system power transition.
1303  * @dev: Device to handle.
1304  * @state: PM transition of the system being carried out.
1305  *
1306  * Execute the ->prepare() callback(s) for given device.  No new children of the
1307  * device may be registered after this function has returned.
1308  */
1309 static int device_prepare(struct device *dev, pm_message_t state)
1310 {
1311         int (*callback)(struct device *) = NULL;
1312         char *info = NULL;
1313         int error = 0;
1314
1315         if (dev->power.syscore)
1316                 return 0;
1317
1318         /*
1319          * If a device's parent goes into runtime suspend at the wrong time,
1320          * it won't be possible to resume the device.  To prevent this we
1321          * block runtime suspend here, during the prepare phase, and allow
1322          * it again during the complete phase.
1323          */
1324         pm_runtime_get_noresume(dev);
1325
1326         device_lock(dev);
1327
1328         dev->power.wakeup_path = device_may_wakeup(dev);
1329
1330         if (dev->pm_domain) {
1331                 info = "preparing power domain ";
1332                 callback = dev->pm_domain->ops.prepare;
1333         } else if (dev->type && dev->type->pm) {
1334                 info = "preparing type ";
1335                 callback = dev->type->pm->prepare;
1336         } else if (dev->class && dev->class->pm) {
1337                 info = "preparing class ";
1338                 callback = dev->class->pm->prepare;
1339         } else if (dev->bus && dev->bus->pm) {
1340                 info = "preparing bus ";
1341                 callback = dev->bus->pm->prepare;
1342         }
1343
1344         if (!callback && dev->driver && dev->driver->pm) {
1345                 info = "preparing driver ";
1346                 callback = dev->driver->pm->prepare;
1347         }
1348
1349         if (callback) {
1350                 error = callback(dev);
1351                 suspend_report_result(callback, error);
1352         }
1353
1354         device_unlock(dev);
1355
1356         if (error)
1357                 pm_runtime_put(dev);
1358
1359         return error;
1360 }
1361
1362 /**
1363  * dpm_prepare - Prepare all non-sysdev devices for a system PM transition.
1364  * @state: PM transition of the system being carried out.
1365  *
1366  * Execute the ->prepare() callback(s) for all devices.
1367  */
1368 int dpm_prepare(pm_message_t state)
1369 {
1370         int error = 0;
1371
1372         might_sleep();
1373
1374         mutex_lock(&dpm_list_mtx);
1375         while (!list_empty(&dpm_list)) {
1376                 struct device *dev = to_device(dpm_list.next);
1377
1378                 get_device(dev);
1379                 mutex_unlock(&dpm_list_mtx);
1380
1381                 error = device_prepare(dev, state);
1382
1383                 mutex_lock(&dpm_list_mtx);
1384                 if (error) {
1385                         if (error == -EAGAIN) {
1386                                 put_device(dev);
1387                                 error = 0;
1388                                 continue;
1389                         }
1390                         printk(KERN_INFO "PM: Device %s not prepared "
1391                                 "for power transition: code %d\n",
1392                                 dev_name(dev), error);
1393                         put_device(dev);
1394                         break;
1395                 }
1396                 dev->power.is_prepared = true;
1397                 if (!list_empty(&dev->power.entry))
1398                         list_move_tail(&dev->power.entry, &dpm_prepared_list);
1399                 put_device(dev);
1400         }
1401         mutex_unlock(&dpm_list_mtx);
1402         return error;
1403 }
1404
1405 /**
1406  * dpm_suspend_start - Prepare devices for PM transition and suspend them.
1407  * @state: PM transition of the system being carried out.
1408  *
1409  * Prepare all non-sysdev devices for system PM transition and execute "suspend"
1410  * callbacks for them.
1411  */
1412 int dpm_suspend_start(pm_message_t state)
1413 {
1414         int error;
1415
1416         error = dpm_prepare(state);
1417         if (error) {
1418                 suspend_stats.failed_prepare++;
1419                 dpm_save_failed_step(SUSPEND_PREPARE);
1420         } else
1421                 error = dpm_suspend(state);
1422         return error;
1423 }
1424 EXPORT_SYMBOL_GPL(dpm_suspend_start);
1425
1426 void __suspend_report_result(const char *function, void *fn, int ret)
1427 {
1428         if (ret)
1429                 printk(KERN_ERR "%s(): %pF returns %d\n", function, fn, ret);
1430 }
1431 EXPORT_SYMBOL_GPL(__suspend_report_result);
1432
1433 /**
1434  * device_pm_wait_for_dev - Wait for suspend/resume of a device to complete.
1435  * @dev: Device to wait for.
1436  * @subordinate: Device that needs to wait for @dev.
1437  */
1438 int device_pm_wait_for_dev(struct device *subordinate, struct device *dev)
1439 {
1440         dpm_wait(dev, subordinate->power.async_suspend);
1441         return async_error;
1442 }
1443 EXPORT_SYMBOL_GPL(device_pm_wait_for_dev);
1444
1445 /**
1446  * dpm_for_each_dev - device iterator.
1447  * @data: data for the callback.
1448  * @fn: function to be called for each device.
1449  *
1450  * Iterate over devices in dpm_list, and call @fn for each device,
1451  * passing it @data.
1452  */
1453 void dpm_for_each_dev(void *data, void (*fn)(struct device *, void *))
1454 {
1455         struct device *dev;
1456
1457         if (!fn)
1458                 return;
1459
1460         device_pm_lock();
1461         list_for_each_entry(dev, &dpm_list, power.entry)
1462                 fn(dev, data);
1463         device_pm_unlock();
1464 }
1465 EXPORT_SYMBOL_GPL(dpm_for_each_dev);