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