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