kernel/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/pm-trace.h>
  27 #include <linux/pm_wakeirq.h>
  28 #include <linux/interrupt.h>
  29 #include <linux/sched.h>
  30 #include <linux/async.h>
  31 #include <linux/suspend.h>
  32 #include <trace/events/power.h>
  33 #include <linux/cpufreq.h>
  34 #include <linux/cpuidle.h>
  35 #include <linux/timer.h>
  36
  37 #include "../base.h"
  38 #include "power.h"
  39
  40 typedef int (*pm_callback_t)(struct device *);
  41
  42 /*
  43  * The entries in the dpm_list list are in a depth first order, simply
  44  * because children are guaranteed to be discovered after parents, and
  45  * are inserted at the back of the list on discovery.
  46  *
  47  * Since device_pm_add() may be called with a device lock held,
  48  * we must never try to acquire a device lock while holding
  49  * dpm_list_mutex.
  50  */
  51
  52 LIST_HEAD(dpm_list);
  53 static LIST_HEAD(dpm_prepared_list);
  54 static LIST_HEAD(dpm_suspended_list);
  55 static LIST_HEAD(dpm_late_early_list);
  56 static LIST_HEAD(dpm_noirq_list);
  57
  58 struct suspend_stats suspend_stats;
  59 static DEFINE_MUTEX(dpm_list_mtx);
  60 static pm_message_t pm_transition;
  61
  62 static int async_error;
  63
  64 static char *pm_verb(int event)
  65 {
  66         switch (event) {
  67         case PM_EVENT_SUSPEND:
  68                 return "suspend";
  69         case PM_EVENT_RESUME:
  70                 return "resume";
  71         case PM_EVENT_FREEZE:
  72                 return "freeze";
  73         case PM_EVENT_QUIESCE:
  74                 return "quiesce";
  75         case PM_EVENT_HIBERNATE:
  76                 return "hibernate";
  77         case PM_EVENT_THAW:
  78                 return "thaw";
  79         case PM_EVENT_RESTORE:
  80                 return "restore";
  81         case PM_EVENT_RECOVER:
  82                 return "recover";
  83         default:
  84                 return "(unknown PM event)";
  85         }
  86 }
  87
  88 /**
  89  * device_pm_sleep_init - Initialize system suspend-related device fields.
  90  * @dev: Device object being initialized.
  91  */
  92 void device_pm_sleep_init(struct device *dev)
  93 {
  94         dev->power.is_prepared = false;
  95         dev->power.is_suspended = false;
  96         dev->power.is_noirq_suspended = false;
  97         dev->power.is_late_suspended = false;
  98         init_completion(&dev->power.completion);
  99         complete_all(&dev->power.completion);
 100         dev->power.wakeup = NULL;
 101         INIT_LIST_HEAD(&dev->power.entry);
 102 }
 103
 104 /**
 105  * device_pm_lock - Lock the list of active devices used by the PM core.
 106  */
 107 void device_pm_lock(void)
 108 {
 109         mutex_lock(&dpm_list_mtx);
 110 }
 111
 112 /**
 113  * device_pm_unlock - Unlock the list of active devices used by the PM core.
 114  */
 115 void device_pm_unlock(void)
 116 {
 117         mutex_unlock(&dpm_list_mtx);
 118 }
 119
 120 /**
 121  * device_pm_add - Add a device to the PM core's list of active devices.
 122  * @dev: Device to add to the list.
 123  */
 124 void device_pm_add(struct device *dev)
 125 {
 126         pr_debug("PM: Adding info for %s:%s\n",
 127                  dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
 128         mutex_lock(&dpm_list_mtx);
 129         if (dev->parent && dev->parent->power.is_prepared)
 130                 dev_warn(dev, "parent %s should not be sleeping\n",
 131                         dev_name(dev->parent));
 132         list_add_tail(&dev->power.entry, &dpm_list);
 133         mutex_unlock(&dpm_list_mtx);
 134 }
 135
 136 /**
 137  * device_pm_remove - Remove a device from the PM core's list of active devices.
 138  * @dev: Device to be removed from the list.
 139  */
 140 void device_pm_remove(struct device *dev)
 141 {
 142         pr_debug("PM: Removing info for %s:%s\n",
 143                  dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
 144         complete_all(&dev->power.completion);
 145         mutex_lock(&dpm_list_mtx);
 146         list_del_init(&dev->power.entry);
 147         mutex_unlock(&dpm_list_mtx);
 148         device_wakeup_disable(dev);
 149         pm_runtime_remove(dev);
 150 }
 151
 152 /**
 153  * device_pm_move_before - Move device in the PM core's list of active devices.
 154  * @deva: Device to move in dpm_list.
 155  * @devb: Device @deva should come before.
 156  */
 157 void device_pm_move_before(struct device *deva, struct device *devb)
 158 {
 159         pr_debug("PM: Moving %s:%s before %s:%s\n",
 160                  deva->bus ? deva->bus->name : "No Bus", dev_name(deva),
 161                  devb->bus ? devb->bus->name : "No Bus", dev_name(devb));
 162         /* Delete deva from dpm_list and reinsert before devb. */
 163         list_move_tail(&deva->power.entry, &devb->power.entry);
 164 }
 165
 166 /**
 167  * device_pm_move_after - Move device in the PM core's list of active devices.
 168  * @deva: Device to move in dpm_list.
 169  * @devb: Device @deva should come after.
 170  */
 171 void device_pm_move_after(struct device *deva, struct device *devb)
 172 {
 173         pr_debug("PM: Moving %s:%s after %s:%s\n",
 174                  deva->bus ? deva->bus->name : "No Bus", dev_name(deva),
 175                  devb->bus ? devb->bus->name : "No Bus", dev_name(devb));
 176         /* Delete deva from dpm_list and reinsert after devb. */
 177         list_move(&deva->power.entry, &devb->power.entry);
 178 }
 179
 180 /**
 181  * device_pm_move_last - Move device to end of the PM core's list of devices.
 182  * @dev: Device to move in dpm_list.
 183  */
 184 void device_pm_move_last(struct device *dev)
 185 {
 186         pr_debug("PM: Moving %s:%s to end of list\n",
 187                  dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
 188         list_move_tail(&dev->power.entry, &dpm_list);
 189 }
 190
 191 static ktime_t initcall_debug_start(struct device *dev)
 192 {
 193         ktime_t calltime = ktime_set(0, 0);
 194
 195         if (pm_print_times_enabled) {
 196                 pr_info("calling  %s+ @ %i, parent: %s\n",
 197                         dev_name(dev), task_pid_nr(current),
 198                         dev->parent ? dev_name(dev->parent) : "none");
 199                 calltime = ktime_get();
 200         }
 201
 202         return calltime;
 203 }
 204
 205 static void initcall_debug_report(struct device *dev, ktime_t calltime,
 206                                   int error, pm_message_t state, char *info)
 207 {
 208         ktime_t rettime;
 209         s64 nsecs;
 210
 211         rettime = ktime_get();
 212         nsecs = (s64) ktime_to_ns(ktime_sub(rettime, calltime));
 213
 214         if (pm_print_times_enabled) {
 215                 pr_info("call %s+ returned %d after %Ld usecs\n", dev_name(dev),
 216                         error, (unsigned long long)nsecs >> 10);
 217         }
 218 }
 219
 220 /**
 221  * dpm_wait - Wait for a PM operation to complete.
 222  * @dev: Device to wait for.
 223  * @async: If unset, wait only if the device's power.async_suspend flag is set.
 224  */
 225 static void dpm_wait(struct device *dev, bool async)
 226 {
 227         if (!dev)
 228                 return;
 229
 230         if (async || (pm_async_enabled && dev->power.async_suspend))
 231                 wait_for_completion(&dev->power.completion);
 232 }
 233
 234 static int dpm_wait_fn(struct device *dev, void *async_ptr)
 235 {
 236         dpm_wait(dev, *((bool *)async_ptr));
 237         return 0;
 238 }
 239
 240 static void dpm_wait_for_children(struct device *dev, bool async)
 241 {
 242        device_for_each_child(dev, &async, dpm_wait_fn);
 243 }
 244
 245 /**
 246  * pm_op - Return the PM operation appropriate for given PM event.
 247  * @ops: PM operations to choose from.
 248  * @state: PM transition of the system being carried out.
 249  */
 250 static pm_callback_t pm_op(const struct dev_pm_ops *ops, pm_message_t state)
 251 {
 252         switch (state.event) {
 253 #ifdef CONFIG_SUSPEND
 254         case PM_EVENT_SUSPEND:
 255                 return ops->suspend;
 256         case PM_EVENT_RESUME:
 257                 return ops->resume;
 258 #endif /* CONFIG_SUSPEND */
 259 #ifdef CONFIG_HIBERNATE_CALLBACKS
 260         case PM_EVENT_FREEZE:
 261         case PM_EVENT_QUIESCE:
 262                 return ops->freeze;
 263         case PM_EVENT_HIBERNATE:
 264                 return ops->poweroff;
 265         case PM_EVENT_THAW:
 266         case PM_EVENT_RECOVER:
 267                 return ops->thaw;
 268                 break;
 269         case PM_EVENT_RESTORE:
 270                 return ops->restore;
 271 #endif /* CONFIG_HIBERNATE_CALLBACKS */
 272         }
 273
 274         return NULL;
 275 }
 276
 277 /**
 278  * pm_late_early_op - Return the PM operation appropriate for given PM event.
 279  * @ops: PM operations to choose from.
 280  * @state: PM transition of the system being carried out.
 281  *
 282  * Runtime PM is disabled for @dev while this function is being executed.
 283  */
 284 static pm_callback_t pm_late_early_op(const struct dev_pm_ops *ops,
 285                                       pm_message_t state)
 286 {
 287         switch (state.event) {
 288 #ifdef CONFIG_SUSPEND
 289         case PM_EVENT_SUSPEND:
 290                 return ops->suspend_late;
 291         case PM_EVENT_RESUME:
 292                 return ops->resume_early;
 293 #endif /* CONFIG_SUSPEND */
 294 #ifdef CONFIG_HIBERNATE_CALLBACKS
 295         case PM_EVENT_FREEZE:
 296         case PM_EVENT_QUIESCE:
 297                 return ops->freeze_late;
 298         case PM_EVENT_HIBERNATE:
 299                 return ops->poweroff_late;
 300         case PM_EVENT_THAW:
 301         case PM_EVENT_RECOVER:
 302                 return ops->thaw_early;
 303         case PM_EVENT_RESTORE:
 304                 return ops->restore_early;
 305 #endif /* CONFIG_HIBERNATE_CALLBACKS */
 306         }
 307
 308         return NULL;
 309 }
 310
 311 /**
 312  * pm_noirq_op - Return the PM operation appropriate for given PM event.
 313  * @ops: PM operations to choose from.
 314  * @state: PM transition of the system being carried out.
 315  *
 316  * The driver of @dev will not receive interrupts while this function is being
 317  * executed.
 318  */
 319 static pm_callback_t pm_noirq_op(const struct dev_pm_ops *ops, pm_message_t state)
 320 {
 321         switch (state.event) {
 322 #ifdef CONFIG_SUSPEND
 323         case PM_EVENT_SUSPEND:
 324                 return ops->suspend_noirq;
 325         case PM_EVENT_RESUME:
 326                 return ops->resume_noirq;
 327 #endif /* CONFIG_SUSPEND */
 328 #ifdef CONFIG_HIBERNATE_CALLBACKS
 329         case PM_EVENT_FREEZE:
 330         case PM_EVENT_QUIESCE:
 331                 return ops->freeze_noirq;
 332         case PM_EVENT_HIBERNATE:
 333                 return ops->poweroff_noirq;
 334         case PM_EVENT_THAW:
 335         case PM_EVENT_RECOVER:
 336                 return ops->thaw_noirq;
 337         case PM_EVENT_RESTORE:
 338                 return ops->restore_noirq;
 339 #endif /* CONFIG_HIBERNATE_CALLBACKS */
 340         }
 341
 342         return NULL;
 343 }
 344
 345 static void pm_dev_dbg(struct device *dev, pm_message_t state, char *info)
 346 {
 347         dev_dbg(dev, "%s%s%s\n", info, pm_verb(state.event),
 348                 ((state.event & PM_EVENT_SLEEP) && device_may_wakeup(dev)) ?
 349                 ", may wakeup" : "");
 350 }
 351
 352 static void pm_dev_err(struct device *dev, pm_message_t state, char *info,
 353                         int error)
 354 {
 355         printk(KERN_ERR "PM: Device %s failed to %s%s: error %d\n",
 356                 dev_name(dev), pm_verb(state.event), info, error);
 357 }
 358
 359 static void dpm_show_time(ktime_t starttime, pm_message_t state, char *info)
 360 {
 361         ktime_t calltime;
 362         u64 usecs64;
 363         int usecs;
 364
 365         calltime = ktime_get();
 366         usecs64 = ktime_to_ns(ktime_sub(calltime, starttime));
 367         do_div(usecs64, NSEC_PER_USEC);
 368         usecs = usecs64;
 369         if (usecs == 0)
 370                 usecs = 1;
 371         pr_info("PM: %s%s%s of devices complete after %ld.%03ld msecs\n",
 372                 info ?: "", info ? " " : "", pm_verb(state.event),
 373                 usecs / USEC_PER_MSEC, usecs % USEC_PER_MSEC);
 374 }
 375
 376 static int dpm_run_callback(pm_callback_t cb, struct device *dev,
 377                             pm_message_t state, char *info)
 378 {
 379         ktime_t calltime;
 380         int error;
 381
 382         if (!cb)
 383                 return 0;
 384
 385         calltime = initcall_debug_start(dev);
 386
 387         pm_dev_dbg(dev, state, info);
 388         trace_device_pm_callback_start(dev, info, state.event);
 389         error = cb(dev);
 390         trace_device_pm_callback_end(dev, error);
 391         suspend_report_result(cb, error);
 392
 393         initcall_debug_report(dev, calltime, error, state, info);
 394
 395         return error;
 396 }
 397
 398 #ifdef CONFIG_DPM_WATCHDOG
 399 struct dpm_watchdog {
 400         struct device           *dev;
 401         struct task_struct      *tsk;
 402         struct timer_list       timer;
 403 };
 404
 405 #define DECLARE_DPM_WATCHDOG_ON_STACK(wd) \
 406         struct dpm_watchdog wd
 407
 408 /**
 409  * dpm_watchdog_handler - Driver suspend / resume watchdog handler.
 410  * @data: Watchdog object address.
 411  *
 412  * Called when a driver has timed out suspending or resuming.
 413  * There's not much we can do here to recover so panic() to
 414  * capture a crash-dump in pstore.
 415  */
 416 static void dpm_watchdog_handler(unsigned long data)
 417 {
 418         struct dpm_watchdog *wd = (void *)data;
 419
 420         dev_emerg(wd->dev, "**** DPM device timeout ****\n");
 421         show_stack(wd->tsk, NULL);
 422         panic("%s %s: unrecoverable failure\n",
 423                 dev_driver_string(wd->dev), dev_name(wd->dev));
 424 }
 425
 426 /**
 427  * dpm_watchdog_set - Enable pm watchdog for given device.
 428  * @wd: Watchdog. Must be allocated on the stack.
 429  * @dev: Device to handle.
 430  */
 431 static void dpm_watchdog_set(struct dpm_watchdog *wd, struct device *dev)
 432 {
 433         struct timer_list *timer = &wd->timer;
 434
 435         wd->dev = dev;
 436         wd->tsk = current;
 437
 438         init_timer_on_stack(timer);
 439         /* use same timeout value for both suspend and resume */
 440         timer->expires = jiffies + HZ * CONFIG_DPM_WATCHDOG_TIMEOUT;
 441         timer->function = dpm_watchdog_handler;
 442         timer->data = (unsigned long)wd;
 443         add_timer(timer);
 444 }
 445
 446 /**
 447  * dpm_watchdog_clear - Disable suspend/resume watchdog.
 448  * @wd: Watchdog to disable.
 449  */
 450 static void dpm_watchdog_clear(struct dpm_watchdog *wd)
 451 {
 452         struct timer_list *timer = &wd->timer;
 453
 454         del_timer_sync(timer);
 455         destroy_timer_on_stack(timer);
 456 }
 457 #else
 458 #define DECLARE_DPM_WATCHDOG_ON_STACK(wd)
 459 #define dpm_watchdog_set(x, y)
 460 #define dpm_watchdog_clear(x)
 461 #endif
 462
 463 /*------------------------- Resume routines -------------------------*/
 464
 465 /**
 466  * device_resume_noirq - Execute an "early resume" callback for given device.
 467  * @dev: Device to handle.
 468  * @state: PM transition of the system being carried out.
 469  * @async: If true, the device is being resumed asynchronously.
 470  *
 471  * The driver of @dev will not receive interrupts while this function is being
 472  * executed.
 473  */
 474 static int device_resume_noirq(struct device *dev, pm_message_t state, bool async)
 475 {
 476         pm_callback_t callback = NULL;
 477         char *info = NULL;
 478         int error = 0;
 479
 480         TRACE_DEVICE(dev);
 481         TRACE_RESUME(0);
 482
 483         if (dev->power.syscore || dev->power.direct_complete)
 484                 goto Out;
 485
 486         if (!dev->power.is_noirq_suspended)
 487                 goto Out;
 488
 489         dpm_wait(dev->parent, async);
 490
 491         if (dev->pm_domain) {
 492                 info = "noirq power domain ";
 493                 callback = pm_noirq_op(&dev->pm_domain->ops, state);
 494         } else if (dev->type && dev->type->pm) {
 495                 info = "noirq type ";
 496                 callback = pm_noirq_op(dev->type->pm, state);
 497         } else if (dev->class && dev->class->pm) {
 498                 info = "noirq class ";
 499                 callback = pm_noirq_op(dev->class->pm, state);
 500         } else if (dev->bus && dev->bus->pm) {
 501                 info = "noirq bus ";
 502                 callback = pm_noirq_op(dev->bus->pm, state);
 503         }
 504
 505         if (!callback && dev->driver && dev->driver->pm) {
 506                 info = "noirq driver ";
 507                 callback = pm_noirq_op(dev->driver->pm, state);
 508         }
 509
 510         error = dpm_run_callback(callback, dev, state, info);
 511         dev->power.is_noirq_suspended = false;
 512
 513  Out:
 514         complete_all(&dev->power.completion);
 515         TRACE_RESUME(error);
 516         return error;
 517 }
 518
 519 static bool is_async(struct device *dev)
 520 {
 521         return dev->power.async_suspend && pm_async_enabled
 522                 && !pm_trace_is_enabled();
 523 }
 524
 525 static void async_resume_noirq(void *data, async_cookie_t cookie)
 526 {
 527         struct device *dev = (struct device *)data;
 528         int error;
 529
 530         error = device_resume_noirq(dev, pm_transition, true);
 531         if (error)
 532                 pm_dev_err(dev, pm_transition, " async", error);
 533
 534         put_device(dev);
 535 }
 536
 537 /**
 538  * dpm_resume_noirq - Execute "noirq resume" callbacks for all devices.
 539  * @state: PM transition of the system being carried out.
 540  *
 541  * Call the "noirq" resume handlers for all devices in dpm_noirq_list and
 542  * enable device drivers to receive interrupts.
 543  */
 544 void dpm_resume_noirq(pm_message_t state)
 545 {
 546         struct device *dev;
 547         ktime_t starttime = ktime_get();
 548
 549         trace_suspend_resume(TPS("dpm_resume_noirq"), state.event, true);
 550         mutex_lock(&dpm_list_mtx);
 551         pm_transition = state;
 552
 553         /*
 554          * Advanced the async threads upfront,
 555          * in case the starting of async threads is
 556          * delayed by non-async resuming devices.
 557          */
 558         list_for_each_entry(dev, &dpm_noirq_list, power.entry) {
 559                 reinit_completion(&dev->power.completion);
 560                 if (is_async(dev)) {
 561                         get_device(dev);
 562                         async_schedule(async_resume_noirq, dev);
 563                 }
 564         }
 565
 566         while (!list_empty(&dpm_noirq_list)) {
 567                 dev = to_device(dpm_noirq_list.next);
 568                 get_device(dev);
 569                 list_move_tail(&dev->power.entry, &dpm_late_early_list);
 570                 mutex_unlock(&dpm_list_mtx);
 571
 572                 if (!is_async(dev)) {
 573                         int error;
 574
 575                         error = device_resume_noirq(dev, state, false);
 576                         if (error) {
 577                                 suspend_stats.failed_resume_noirq++;
 578                                 dpm_save_failed_step(SUSPEND_RESUME_NOIRQ);
 579                                 dpm_save_failed_dev(dev_name(dev));
 580                                 pm_dev_err(dev, state, " noirq", error);
 581                         }
 582                 }
 583
 584                 mutex_lock(&dpm_list_mtx);
 585                 put_device(dev);
 586         }
 587         mutex_unlock(&dpm_list_mtx);
 588         async_synchronize_full();
 589         dpm_show_time(starttime, state, "noirq");
 590         resume_device_irqs();
 591         device_wakeup_disarm_wake_irqs();
 592         cpuidle_resume();
 593         trace_suspend_resume(TPS("dpm_resume_noirq"), state.event, false);
 594 }
 595
 596 /**
 597  * device_resume_early - Execute an "early resume" callback for given device.
 598  * @dev: Device to handle.
 599  * @state: PM transition of the system being carried out.
 600  * @async: If true, the device is being resumed asynchronously.
 601  *
 602  * Runtime PM is disabled for @dev while this function is being executed.
 603  */
 604 static int device_resume_early(struct device *dev, pm_message_t state, bool async)
 605 {
 606         pm_callback_t callback = NULL;
 607         char *info = NULL;
 608         int error = 0;
 609
 610         TRACE_DEVICE(dev);
 611         TRACE_RESUME(0);
 612
 613         if (dev->power.syscore || dev->power.direct_complete)
 614                 goto Out;
 615
 616         if (!dev->power.is_late_suspended)
 617                 goto Out;
 618
 619         dpm_wait(dev->parent, async);
 620
 621         if (dev->pm_domain) {
 622                 info = "early power domain ";
 623                 callback = pm_late_early_op(&dev->pm_domain->ops, state);
 624         } else if (dev->type && dev->type->pm) {
 625                 info = "early type ";
 626                 callback = pm_late_early_op(dev->type->pm, state);
 627         } else if (dev->class && dev->class->pm) {
 628                 info = "early class ";
 629                 callback = pm_late_early_op(dev->class->pm, state);
 630         } else if (dev->bus && dev->bus->pm) {
 631                 info = "early bus ";
 632                 callback = pm_late_early_op(dev->bus->pm, state);
 633         }
 634
 635         if (!callback && dev->driver && dev->driver->pm) {
 636                 info = "early driver ";
 637                 callback = pm_late_early_op(dev->driver->pm, state);
 638         }
 639
 640         error = dpm_run_callback(callback, dev, state, info);
 641         dev->power.is_late_suspended = false;
 642
 643  Out:
 644         TRACE_RESUME(error);
 645
 646         pm_runtime_enable(dev);
 647         complete_all(&dev->power.completion);
 648         return error;
 649 }
 650
 651 static void async_resume_early(void *data, async_cookie_t cookie)
 652 {
 653         struct device *dev = (struct device *)data;
 654         int error;
 655
 656         error = device_resume_early(dev, pm_transition, true);
 657         if (error)
 658                 pm_dev_err(dev, pm_transition, " async", error);
 659
 660         put_device(dev);
 661 }
 662
 663 /**
 664  * dpm_resume_early - Execute "early resume" callbacks for all devices.
 665  * @state: PM transition of the system being carried out.
 666  */
 667 void dpm_resume_early(pm_message_t state)
 668 {
 669         struct device *dev;
 670         ktime_t starttime = ktime_get();
 671
 672         trace_suspend_resume(TPS("dpm_resume_early"), state.event, true);
 673         mutex_lock(&dpm_list_mtx);
 674         pm_transition = state;
 675
 676         /*
 677          * Advanced the async threads upfront,
 678          * in case the starting of async threads is
 679          * delayed by non-async resuming devices.
 680          */
 681         list_for_each_entry(dev, &dpm_late_early_list, power.entry) {
 682                 reinit_completion(&dev->power.completion);
 683                 if (is_async(dev)) {
 684                         get_device(dev);
 685                         async_schedule(async_resume_early, dev);
 686                 }
 687         }
 688
 689         while (!list_empty(&dpm_late_early_list)) {
 690                 dev = to_device(dpm_late_early_list.next);
 691                 get_device(dev);
 692                 list_move_tail(&dev->power.entry, &dpm_suspended_list);
 693                 mutex_unlock(&dpm_list_mtx);
 694
 695                 if (!is_async(dev)) {
 696                         int error;
 697
 698                         error = device_resume_early(dev, state, false);
 699                         if (error) {
 700                                 suspend_stats.failed_resume_early++;
 701                                 dpm_save_failed_step(SUSPEND_RESUME_EARLY);
 702                                 dpm_save_failed_dev(dev_name(dev));
 703                                 pm_dev_err(dev, state, " early", error);
 704                         }
 705                 }
 706                 mutex_lock(&dpm_list_mtx);
 707                 put_device(dev);
 708         }
 709         mutex_unlock(&dpm_list_mtx);
 710         async_synchronize_full();
 711         dpm_show_time(starttime, state, "early");
 712         trace_suspend_resume(TPS("dpm_resume_early"), state.event, false);
 713 }
 714
 715 /**
 716  * dpm_resume_start - Execute "noirq" and "early" device callbacks.
 717  * @state: PM transition of the system being carried out.
 718  */
 719 void dpm_resume_start(pm_message_t state)
 720 {
 721         dpm_resume_noirq(state);
 722         dpm_resume_early(state);
 723 }
 724 EXPORT_SYMBOL_GPL(dpm_resume_start);
 725
 726 /**
 727  * device_resume - Execute "resume" callbacks for given device.
 728  * @dev: Device to handle.
 729  * @state: PM transition of the system being carried out.
 730  * @async: If true, the device is being resumed asynchronously.
 731  */
 732 static int device_resume(struct device *dev, pm_message_t state, bool async)
 733 {
 734         pm_callback_t callback = NULL;
 735         char *info = NULL;
 736         int error = 0;
 737         DECLARE_DPM_WATCHDOG_ON_STACK(wd);
 738
 739         TRACE_DEVICE(dev);
 740         TRACE_RESUME(0);
 741
 742         if (dev->power.syscore)
 743                 goto Complete;
 744
 745         if (dev->power.direct_complete) {
 746                 /* Match the pm_runtime_disable() in __device_suspend(). */
 747                 pm_runtime_enable(dev);
 748                 goto Complete;
 749         }
 750
 751         dpm_wait(dev->parent, async);
 752         dpm_watchdog_set(&wd, dev);
 753         device_lock(dev);
 754
 755         /*
 756          * This is a fib.  But we'll allow new children to be added below
 757          * a resumed device, even if the device hasn't been completed yet.
 758          */
 759         dev->power.is_prepared = false;
 760
 761         if (!dev->power.is_suspended)
 762                 goto Unlock;
 763
 764         if (dev->pm_domain) {
 765                 info = "power domain ";
 766                 callback = pm_op(&dev->pm_domain->ops, state);
 767                 goto Driver;
 768         }
 769
 770         if (dev->type && dev->type->pm) {
 771                 info = "type ";
 772                 callback = pm_op(dev->type->pm, state);
 773                 goto Driver;
 774         }
 775
 776         if (dev->class) {
 777                 if (dev->class->pm) {
 778                         info = "class ";
 779                         callback = pm_op(dev->class->pm, state);
 780                         goto Driver;
 781                 } else if (dev->class->resume) {
 782                         info = "legacy class ";
 783                         callback = dev->class->resume;
 784                         goto End;
 785                 }
 786         }
 787
 788         if (dev->bus) {
 789                 if (dev->bus->pm) {
 790                         info = "bus ";
 791                         callback = pm_op(dev->bus->pm, state);
 792                 } else if (dev->bus->resume) {
 793                         info = "legacy bus ";
 794                         callback = dev->bus->resume;
 795                         goto End;
 796                 }
 797         }
 798
 799  Driver:
 800         if (!callback && dev->driver && dev->driver->pm) {
 801                 info = "driver ";
 802                 callback = pm_op(dev->driver->pm, state);
 803         }
 804
 805  End:
 806         error = dpm_run_callback(callback, dev, state, info);
 807         dev->power.is_suspended = false;
 808
 809  Unlock:
 810         device_unlock(dev);
 811         dpm_watchdog_clear(&wd);
 812
 813  Complete:
 814         complete_all(&dev->power.completion);
 815
 816         TRACE_RESUME(error);
 817
 818         return error;
 819 }
 820
 821 static void async_resume(void *data, async_cookie_t cookie)
 822 {
 823         struct device *dev = (struct device *)data;
 824         int error;
 825
 826         error = device_resume(dev, pm_transition, true);
 827         if (error)
 828                 pm_dev_err(dev, pm_transition, " async", error);
 829         put_device(dev);
 830 }
 831
 832 /**
 833  * dpm_resume - Execute "resume" callbacks for non-sysdev devices.
 834  * @state: PM transition of the system being carried out.
 835  *
 836  * Execute the appropriate "resume" callback for all devices whose status
 837  * indicates that they are suspended.
 838  */
 839 void dpm_resume(pm_message_t state)
 840 {
 841         struct device *dev;
 842         ktime_t starttime = ktime_get();
 843
 844         trace_suspend_resume(TPS("dpm_resume"), state.event, true);
 845         might_sleep();
 846
 847         mutex_lock(&dpm_list_mtx);
 848         pm_transition = state;
 849         async_error = 0;
 850
 851         list_for_each_entry(dev, &dpm_suspended_list, power.entry) {
 852                 reinit_completion(&dev->power.completion);
 853                 if (is_async(dev)) {
 854                         get_device(dev);
 855                         async_schedule(async_resume, dev);
 856                 }
 857         }
 858
 859         while (!list_empty(&dpm_suspended_list)) {
 860                 dev = to_device(dpm_suspended_list.next);
 861                 get_device(dev);
 862                 if (!is_async(dev)) {
 863                         int error;
 864
 865                         mutex_unlock(&dpm_list_mtx);
 866
 867                         error = device_resume(dev, state, false);
 868                         if (error) {
 869                                 suspend_stats.failed_resume++;
 870                                 dpm_save_failed_step(SUSPEND_RESUME);
 871                                 dpm_save_failed_dev(dev_name(dev));
 872                                 pm_dev_err(dev, state, "", error);
 873                         }
 874
 875                         mutex_lock(&dpm_list_mtx);
 876                 }
 877                 if (!list_empty(&dev->power.entry))
 878                         list_move_tail(&dev->power.entry, &dpm_prepared_list);
 879                 put_device(dev);
 880         }
 881         mutex_unlock(&dpm_list_mtx);
 882         async_synchronize_full();
 883         dpm_show_time(starttime, state, NULL);
 884
 885         cpufreq_resume();
 886         trace_suspend_resume(TPS("dpm_resume"), state.event, false);
 887 }
 888
 889 /**
 890  * device_complete - Complete a PM transition for given device.
 891  * @dev: Device to handle.
 892  * @state: PM transition of the system being carried out.
 893  */
 894 static void device_complete(struct device *dev, pm_message_t state)
 895 {
 896         void (*callback)(struct device *) = NULL;
 897         char *info = NULL;
 898
 899         if (dev->power.syscore)
 900                 return;
 901
 902         device_lock(dev);
 903
 904         if (dev->pm_domain) {
 905                 info = "completing power domain ";
 906                 callback = dev->pm_domain->ops.complete;
 907         } else if (dev->type && dev->type->pm) {
 908                 info = "completing type ";
 909                 callback = dev->type->pm->complete;
 910         } else if (dev->class && dev->class->pm) {
 911                 info = "completing class ";
 912                 callback = dev->class->pm->complete;
 913         } else if (dev->bus && dev->bus->pm) {
 914                 info = "completing bus ";
 915                 callback = dev->bus->pm->complete;
 916         }
 917
 918         if (!callback && dev->driver && dev->driver->pm) {
 919                 info = "completing driver ";
 920                 callback = dev->driver->pm->complete;
 921         }
 922
 923         if (callback) {
 924                 pm_dev_dbg(dev, state, info);
 925                 callback(dev);
 926         }
 927
 928         device_unlock(dev);
 929
 930         pm_runtime_put(dev);
 931 }
 932
 933 /**
 934  * dpm_complete - Complete a PM transition for all non-sysdev devices.
 935  * @state: PM transition of the system being carried out.
 936  *
 937  * Execute the ->complete() callbacks for all devices whose PM status is not
 938  * DPM_ON (this allows new devices to be registered).
 939  */
 940 void dpm_complete(pm_message_t state)
 941 {
 942         struct list_head list;
 943
 944         trace_suspend_resume(TPS("dpm_complete"), state.event, true);
 945         might_sleep();
 946
 947         INIT_LIST_HEAD(&list);
 948         mutex_lock(&dpm_list_mtx);
 949         while (!list_empty(&dpm_prepared_list)) {
 950                 struct device *dev = to_device(dpm_prepared_list.prev);
 951
 952                 get_device(dev);
 953                 dev->power.is_prepared = false;
 954                 list_move(&dev->power.entry, &list);
 955                 mutex_unlock(&dpm_list_mtx);
 956
 957                 trace_device_pm_callback_start(dev, "", state.event);
 958                 device_complete(dev, state);
 959                 trace_device_pm_callback_end(dev, 0);
 960
 961                 mutex_lock(&dpm_list_mtx);
 962                 put_device(dev);
 963         }
 964         list_splice(&list, &dpm_list);
 965         mutex_unlock(&dpm_list_mtx);
 966         trace_suspend_resume(TPS("dpm_complete"), state.event, false);
 967 }
 968
 969 /**
 970  * dpm_resume_end - Execute "resume" callbacks and complete system transition.
 971  * @state: PM transition of the system being carried out.
 972  *
 973  * Execute "resume" callbacks for all devices and complete the PM transition of
 974  * the system.
 975  */
 976 void dpm_resume_end(pm_message_t state)
 977 {
 978         dpm_resume(state);
 979         dpm_complete(state);
 980 }
 981 EXPORT_SYMBOL_GPL(dpm_resume_end);
 982
 983
 984 /*------------------------- Suspend routines -------------------------*/
 985
 986 /**
 987  * resume_event - Return a "resume" message for given "suspend" sleep state.
 988  * @sleep_state: PM message representing a sleep state.
 989  *
 990  * Return a PM message representing the resume event corresponding to given
 991  * sleep state.
 992  */
 993 static pm_message_t resume_event(pm_message_t sleep_state)
 994 {
 995         switch (sleep_state.event) {
 996         case PM_EVENT_SUSPEND:
 997                 return PMSG_RESUME;
 998         case PM_EVENT_FREEZE:
 999         case PM_EVENT_QUIESCE:
1000                 return PMSG_RECOVER;
1001         case PM_EVENT_HIBERNATE:
1002                 return PMSG_RESTORE;
1003         }
1004         return PMSG_ON;
1005 }
1006
1007 /**
1008  * device_suspend_noirq - Execute a "late suspend" callback for given device.
1009  * @dev: Device to handle.
1010  * @state: PM transition of the system being carried out.
1011  * @async: If true, the device is being suspended asynchronously.
1012  *
1013  * The driver of @dev will not receive interrupts while this function is being
1014  * executed.
1015  */
1016 static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool async)
1017 {
1018         pm_callback_t callback = NULL;
1019         char *info = NULL;
1020         int error = 0;
1021
1022         TRACE_DEVICE(dev);
1023         TRACE_SUSPEND(0);
1024
1025         dpm_wait_for_children(dev, async);
1026
1027         if (async_error)
1028                 goto Complete;
1029
1030         if (pm_wakeup_pending()) {
1031                 async_error = -EBUSY;
1032                 goto Complete;
1033         }
1034
1035         if (dev->power.syscore || dev->power.direct_complete)
1036                 goto Complete;
1037
1038         if (dev->pm_domain) {
1039                 info = "noirq power domain ";
1040                 callback = pm_noirq_op(&dev->pm_domain->ops, state);
1041         } else if (dev->type && dev->type->pm) {
1042                 info = "noirq type ";
1043                 callback = pm_noirq_op(dev->type->pm, state);
1044         } else if (dev->class && dev->class->pm) {
1045                 info = "noirq class ";
1046                 callback = pm_noirq_op(dev->class->pm, state);
1047         } else if (dev->bus && dev->bus->pm) {
1048                 info = "noirq bus ";
1049                 callback = pm_noirq_op(dev->bus->pm, state);
1050         }
1051
1052         if (!callback && dev->driver && dev->driver->pm) {
1053                 info = "noirq driver ";
1054                 callback = pm_noirq_op(dev->driver->pm, state);
1055         }
1056
1057         error = dpm_run_callback(callback, dev, state, info);
1058         if (!error)
1059                 dev->power.is_noirq_suspended = true;
1060         else
1061                 async_error = error;
1062
1063 Complete:
1064         complete_all(&dev->power.completion);
1065         TRACE_SUSPEND(error);
1066         return error;
1067 }
1068
1069 static void async_suspend_noirq(void *data, async_cookie_t cookie)
1070 {
1071         struct device *dev = (struct device *)data;
1072         int error;
1073
1074         error = __device_suspend_noirq(dev, pm_transition, true);
1075         if (error) {
1076                 dpm_save_failed_dev(dev_name(dev));
1077                 pm_dev_err(dev, pm_transition, " async", error);
1078         }
1079
1080         put_device(dev);
1081 }
1082
1083 static int device_suspend_noirq(struct device *dev)
1084 {
1085         reinit_completion(&dev->power.completion);
1086
1087         if (is_async(dev)) {
1088                 get_device(dev);
1089                 async_schedule(async_suspend_noirq, dev);
1090                 return 0;
1091         }
1092         return __device_suspend_noirq(dev, pm_transition, false);
1093 }
1094
1095 /**
1096  * dpm_suspend_noirq - Execute "noirq suspend" callbacks for all devices.
1097  * @state: PM transition of the system being carried out.
1098  *
1099  * Prevent device drivers from receiving interrupts and call the "noirq" suspend
1100  * handlers for all non-sysdev devices.
1101  */
1102 int dpm_suspend_noirq(pm_message_t state)
1103 {
1104         ktime_t starttime = ktime_get();
1105         int error = 0;
1106
1107         trace_suspend_resume(TPS("dpm_suspend_noirq"), state.event, true);
1108         cpuidle_pause();
1109         device_wakeup_arm_wake_irqs();
1110         suspend_device_irqs();
1111         mutex_lock(&dpm_list_mtx);
1112         pm_transition = state;
1113         async_error = 0;
1114
1115         while (!list_empty(&dpm_late_early_list)) {
1116                 struct device *dev = to_device(dpm_late_early_list.prev);
1117
1118                 get_device(dev);
1119                 mutex_unlock(&dpm_list_mtx);
1120
1121                 error = device_suspend_noirq(dev);
1122
1123                 mutex_lock(&dpm_list_mtx);
1124                 if (error) {
1125                         pm_dev_err(dev, state, " noirq", error);
1126                         dpm_save_failed_dev(dev_name(dev));
1127                         put_device(dev);
1128                         break;
1129                 }
1130                 if (!list_empty(&dev->power.entry))
1131                         list_move(&dev->power.entry, &dpm_noirq_list);
1132                 put_device(dev);
1133
1134                 if (async_error)
1135                         break;
1136         }
1137         mutex_unlock(&dpm_list_mtx);
1138         async_synchronize_full();
1139         if (!error)
1140                 error = async_error;
1141
1142         if (error) {
1143                 suspend_stats.failed_suspend_noirq++;
1144                 dpm_save_failed_step(SUSPEND_SUSPEND_NOIRQ);
1145                 dpm_resume_noirq(resume_event(state));
1146         } else {
1147                 dpm_show_time(starttime, state, "noirq");
1148         }
1149         trace_suspend_resume(TPS("dpm_suspend_noirq"), state.event, false);
1150         return error;
1151 }
1152
1153 /**
1154  * device_suspend_late - Execute a "late suspend" callback for given device.
1155  * @dev: Device to handle.
1156  * @state: PM transition of the system being carried out.
1157  * @async: If true, the device is being suspended asynchronously.
1158  *
1159  * Runtime PM is disabled for @dev while this function is being executed.
1160  */
1161 static int __device_suspend_late(struct device *dev, pm_message_t state, bool async)
1162 {
1163         pm_callback_t callback = NULL;
1164         char *info = NULL;
1165         int error = 0;
1166
1167         TRACE_DEVICE(dev);
1168         TRACE_SUSPEND(0);
1169
1170         __pm_runtime_disable(dev, false);
1171
1172         dpm_wait_for_children(dev, async);
1173
1174         if (async_error)
1175                 goto Complete;
1176
1177         if (pm_wakeup_pending()) {
1178                 async_error = -EBUSY;
1179                 goto Complete;
1180         }
1181
1182         if (dev->power.syscore || dev->power.direct_complete)
1183                 goto Complete;
1184
1185         if (dev->pm_domain) {
1186                 info = "late power domain ";
1187                 callback = pm_late_early_op(&dev->pm_domain->ops, state);
1188         } else if (dev->type && dev->type->pm) {
1189                 info = "late type ";
1190                 callback = pm_late_early_op(dev->type->pm, state);
1191         } else if (dev->class && dev->class->pm) {
1192                 info = "late class ";
1193                 callback = pm_late_early_op(dev->class->pm, state);
1194         } else if (dev->bus && dev->bus->pm) {
1195                 info = "late bus ";
1196                 callback = pm_late_early_op(dev->bus->pm, state);
1197         }
1198
1199         if (!callback && dev->driver && dev->driver->pm) {
1200                 info = "late driver ";
1201                 callback = pm_late_early_op(dev->driver->pm, state);
1202         }
1203
1204         error = dpm_run_callback(callback, dev, state, info);
1205         if (!error)
1206                 dev->power.is_late_suspended = true;
1207         else
1208                 async_error = error;
1209
1210 Complete:
1211         TRACE_SUSPEND(error);
1212         complete_all(&dev->power.completion);
1213         return error;
1214 }
1215
1216 static void async_suspend_late(void *data, async_cookie_t cookie)
1217 {
1218         struct device *dev = (struct device *)data;
1219         int error;
1220
1221         error = __device_suspend_late(dev, pm_transition, true);
1222         if (error) {
1223                 dpm_save_failed_dev(dev_name(dev));
1224                 pm_dev_err(dev, pm_transition, " async", error);
1225         }
1226         put_device(dev);
1227 }
1228
1229 static int device_suspend_late(struct device *dev)
1230 {
1231         reinit_completion(&dev->power.completion);
1232
1233         if (is_async(dev)) {
1234                 get_device(dev);
1235                 async_schedule(async_suspend_late, dev);
1236                 return 0;
1237         }
1238
1239         return __device_suspend_late(dev, pm_transition, false);
1240 }
1241
1242 /**
1243  * dpm_suspend_late - Execute "late suspend" callbacks for all devices.
1244  * @state: PM transition of the system being carried out.
1245  */
1246 int dpm_suspend_late(pm_message_t state)
1247 {
1248         ktime_t starttime = ktime_get();
1249         int error = 0;
1250
1251         trace_suspend_resume(TPS("dpm_suspend_late"), state.event, true);
1252         mutex_lock(&dpm_list_mtx);
1253         pm_transition = state;
1254         async_error = 0;
1255
1256         while (!list_empty(&dpm_suspended_list)) {
1257                 struct device *dev = to_device(dpm_suspended_list.prev);
1258
1259                 get_device(dev);
1260                 mutex_unlock(&dpm_list_mtx);
1261
1262                 error = device_suspend_late(dev);
1263
1264                 mutex_lock(&dpm_list_mtx);
1265                 if (!list_empty(&dev->power.entry))
1266                         list_move(&dev->power.entry, &dpm_late_early_list);
1267
1268                 if (error) {
1269                         pm_dev_err(dev, state, " late", error);
1270                         dpm_save_failed_dev(dev_name(dev));
1271                         put_device(dev);
1272                         break;
1273                 }
1274                 put_device(dev);
1275
1276                 if (async_error)
1277                         break;
1278         }
1279         mutex_unlock(&dpm_list_mtx);
1280         async_synchronize_full();
1281         if (!error)
1282                 error = async_error;
1283         if (error) {
1284                 suspend_stats.failed_suspend_late++;
1285                 dpm_save_failed_step(SUSPEND_SUSPEND_LATE);
1286                 dpm_resume_early(resume_event(state));
1287         } else {
1288                 dpm_show_time(starttime, state, "late");
1289         }
1290         trace_suspend_resume(TPS("dpm_suspend_late"), state.event, false);
1291         return error;
1292 }
1293
1294 /**
1295  * dpm_suspend_end - Execute "late" and "noirq" device suspend callbacks.
1296  * @state: PM transition of the system being carried out.
1297  */
1298 int dpm_suspend_end(pm_message_t state)
1299 {
1300         int error = dpm_suspend_late(state);
1301         if (error)
1302                 return error;
1303
1304         error = dpm_suspend_noirq(state);
1305         if (error) {
1306                 dpm_resume_early(resume_event(state));
1307                 return error;
1308         }
1309
1310         return 0;
1311 }
1312 EXPORT_SYMBOL_GPL(dpm_suspend_end);
1313
1314 /**
1315  * legacy_suspend - Execute a legacy (bus or class) suspend callback for device.
1316  * @dev: Device to suspend.
1317  * @state: PM transition of the system being carried out.
1318  * @cb: Suspend callback to execute.
1319  * @info: string description of caller.
1320  */
1321 static int legacy_suspend(struct device *dev, pm_message_t state,
1322                           int (*cb)(struct device *dev, pm_message_t state),
1323                           char *info)
1324 {
1325         int error;
1326         ktime_t calltime;
1327
1328         calltime = initcall_debug_start(dev);
1329
1330         trace_device_pm_callback_start(dev, info, state.event);
1331         error = cb(dev, state);
1332         trace_device_pm_callback_end(dev, error);
1333         suspend_report_result(cb, error);
1334
1335         initcall_debug_report(dev, calltime, error, state, info);
1336
1337         return error;
1338 }
1339
1340 /**
1341  * device_suspend - Execute "suspend" callbacks for given device.
1342  * @dev: Device to handle.
1343  * @state: PM transition of the system being carried out.
1344  * @async: If true, the device is being suspended asynchronously.
1345  */
1346 static int __device_suspend(struct device *dev, pm_message_t state, bool async)
1347 {
1348         pm_callback_t callback = NULL;
1349         char *info = NULL;
1350         int error = 0;
1351         DECLARE_DPM_WATCHDOG_ON_STACK(wd);
1352
1353         TRACE_DEVICE(dev);
1354         TRACE_SUSPEND(0);
1355
1356         dpm_wait_for_children(dev, async);
1357
1358         if (async_error)
1359                 goto Complete;
1360
1361         /*
1362          * If a device configured to wake up the system from sleep states
1363          * has been suspended at run time and there's a resume request pending
1364          * for it, this is equivalent to the device signaling wakeup, so the
1365          * system suspend operation should be aborted.
1366          */
1367         if (pm_runtime_barrier(dev) && device_may_wakeup(dev))
1368                 pm_wakeup_event(dev, 0);
1369
1370         if (pm_wakeup_pending()) {
1371                 async_error = -EBUSY;
1372                 goto Complete;
1373         }
1374
1375         if (dev->power.syscore)
1376                 goto Complete;
1377
1378         if (dev->power.direct_complete) {
1379                 if (pm_runtime_status_suspended(dev)) {
1380                         pm_runtime_disable(dev);
1381                         if (pm_runtime_status_suspended(dev))
1382                                 goto Complete;
1383
1384                         pm_runtime_enable(dev);
1385                 }
1386                 dev->power.direct_complete = false;
1387         }
1388
1389         dpm_watchdog_set(&wd, dev);
1390         device_lock(dev);
1391
1392         if (dev->pm_domain) {
1393                 info = "power domain ";
1394                 callback = pm_op(&dev->pm_domain->ops, state);
1395                 goto Run;
1396         }
1397
1398         if (dev->type && dev->type->pm) {
1399                 info = "type ";
1400                 callback = pm_op(dev->type->pm, state);
1401                 goto Run;
1402         }
1403
1404         if (dev->class) {
1405                 if (dev->class->pm) {
1406                         info = "class ";
1407                         callback = pm_op(dev->class->pm, state);
1408                         goto Run;
1409                 } else if (dev->class->suspend) {
1410                         pm_dev_dbg(dev, state, "legacy class ");
1411                         error = legacy_suspend(dev, state, dev->class->suspend,
1412                                                 "legacy class ");
1413                         goto End;
1414                 }
1415         }
1416
1417         if (dev->bus) {
1418                 if (dev->bus->pm) {
1419                         info = "bus ";
1420                         callback = pm_op(dev->bus->pm, state);
1421                 } else if (dev->bus->suspend) {
1422                         pm_dev_dbg(dev, state, "legacy bus ");
1423                         error = legacy_suspend(dev, state, dev->bus->suspend,
1424                                                 "legacy bus ");
1425                         goto End;
1426                 }
1427         }
1428
1429  Run:
1430         if (!callback && dev->driver && dev->driver->pm) {
1431                 info = "driver ";
1432                 callback = pm_op(dev->driver->pm, state);
1433         }
1434
1435         error = dpm_run_callback(callback, dev, state, info);
1436
1437  End:
1438         if (!error) {
1439                 struct device *parent = dev->parent;
1440
1441                 dev->power.is_suspended = true;
1442                 if (parent) {
1443                         spin_lock_irq(&parent->power.lock);
1444
1445                         dev->parent->power.direct_complete = false;
1446                         if (dev->power.wakeup_path
1447                             && !dev->parent->power.ignore_children)
1448                                 dev->parent->power.wakeup_path = true;
1449
1450                         spin_unlock_irq(&parent->power.lock);
1451                 }
1452         }
1453
1454         device_unlock(dev);
1455         dpm_watchdog_clear(&wd);
1456
1457  Complete:
1458         complete_all(&dev->power.completion);
1459         if (error)
1460                 async_error = error;
1461
1462         TRACE_SUSPEND(error);
1463         return error;
1464 }
1465
1466 static void async_suspend(void *data, async_cookie_t cookie)
1467 {
1468         struct device *dev = (struct device *)data;
1469         int error;
1470
1471         error = __device_suspend(dev, pm_transition, true);
1472         if (error) {
1473                 dpm_save_failed_dev(dev_name(dev));
1474                 pm_dev_err(dev, pm_transition, " async", error);
1475         }
1476
1477         put_device(dev);
1478 }
1479
1480 static int device_suspend(struct device *dev)
1481 {
1482         reinit_completion(&dev->power.completion);
1483
1484         if (is_async(dev)) {
1485                 get_device(dev);
1486                 async_schedule(async_suspend, dev);
1487                 return 0;
1488         }
1489
1490         return __device_suspend(dev, pm_transition, false);
1491 }
1492
1493 /**
1494  * dpm_suspend - Execute "suspend" callbacks for all non-sysdev devices.
1495  * @state: PM transition of the system being carried out.
1496  */
1497 int dpm_suspend(pm_message_t state)
1498 {
1499         ktime_t starttime = ktime_get();
1500         int error = 0;
1501
1502         trace_suspend_resume(TPS("dpm_suspend"), state.event, true);
1503         might_sleep();
1504
1505         cpufreq_suspend();
1506
1507         mutex_lock(&dpm_list_mtx);
1508         pm_transition = state;
1509         async_error = 0;
1510         while (!list_empty(&dpm_prepared_list)) {
1511                 struct device *dev = to_device(dpm_prepared_list.prev);
1512
1513                 get_device(dev);
1514                 mutex_unlock(&dpm_list_mtx);
1515
1516                 error = device_suspend(dev);
1517
1518                 mutex_lock(&dpm_list_mtx);
1519                 if (error) {
1520                         pm_dev_err(dev, state, "", error);
1521                         dpm_save_failed_dev(dev_name(dev));
1522                         put_device(dev);
1523                         break;
1524                 }
1525                 if (!list_empty(&dev->power.entry))
1526                         list_move(&dev->power.entry, &dpm_suspended_list);
1527                 put_device(dev);
1528                 if (async_error)
1529                         break;
1530         }
1531         mutex_unlock(&dpm_list_mtx);
1532         async_synchronize_full();
1533         if (!error)
1534                 error = async_error;
1535         if (error) {
1536                 suspend_stats.failed_suspend++;
1537                 dpm_save_failed_step(SUSPEND_SUSPEND);
1538         } else
1539                 dpm_show_time(starttime, state, NULL);
1540         trace_suspend_resume(TPS("dpm_suspend"), state.event, false);
1541         return error;
1542 }
1543
1544 /**
1545  * device_prepare - Prepare a device for system power transition.
1546  * @dev: Device to handle.
1547  * @state: PM transition of the system being carried out.
1548  *
1549  * Execute the ->prepare() callback(s) for given device.  No new children of the
1550  * device may be registered after this function has returned.
1551  */
1552 static int device_prepare(struct device *dev, pm_message_t state)
1553 {
1554         int (*callback)(struct device *) = NULL;
1555         char *info = NULL;
1556         int ret = 0;
1557
1558         if (dev->power.syscore)
1559                 return 0;
1560
1561         /*
1562          * If a device's parent goes into runtime suspend at the wrong time,
1563          * it won't be possible to resume the device.  To prevent this we
1564          * block runtime suspend here, during the prepare phase, and allow
1565          * it again during the complete phase.
1566          */
1567         pm_runtime_get_noresume(dev);
1568
1569         device_lock(dev);
1570
1571         dev->power.wakeup_path = device_may_wakeup(dev);
1572
1573         if (dev->pm_domain) {
1574                 info = "preparing power domain ";
1575                 callback = dev->pm_domain->ops.prepare;
1576         } else if (dev->type && dev->type->pm) {
1577                 info = "preparing type ";
1578                 callback = dev->type->pm->prepare;
1579         } else if (dev->class && dev->class->pm) {
1580                 info = "preparing class ";
1581                 callback = dev->class->pm->prepare;
1582         } else if (dev->bus && dev->bus->pm) {
1583                 info = "preparing bus ";
1584                 callback = dev->bus->pm->prepare;
1585         }
1586
1587         if (!callback && dev->driver && dev->driver->pm) {
1588                 info = "preparing driver ";
1589                 callback = dev->driver->pm->prepare;
1590         }
1591
1592         if (callback)
1593                 ret = callback(dev);
1594
1595         device_unlock(dev);
1596
1597         if (ret < 0) {
1598                 suspend_report_result(callback, ret);
1599                 pm_runtime_put(dev);
1600                 return ret;
1601         }
1602         /*
1603          * A positive return value from ->prepare() means "this device appears
1604          * to be runtime-suspended and its state is fine, so if it really is
1605          * runtime-suspended, you can leave it in that state provided that you
1606          * will do the same thing with all of its descendants".  This only
1607          * applies to suspend transitions, however.
1608          */
1609         spin_lock_irq(&dev->power.lock);
1610         dev->power.direct_complete = ret > 0 && state.event == PM_EVENT_SUSPEND;
1611         spin_unlock_irq(&dev->power.lock);
1612         return 0;
1613 }
1614
1615 /**
1616  * dpm_prepare - Prepare all non-sysdev devices for a system PM transition.
1617  * @state: PM transition of the system being carried out.
1618  *
1619  * Execute the ->prepare() callback(s) for all devices.
1620  */
1621 int dpm_prepare(pm_message_t state)
1622 {
1623         int error = 0;
1624
1625         trace_suspend_resume(TPS("dpm_prepare"), state.event, true);
1626         might_sleep();
1627
1628         mutex_lock(&dpm_list_mtx);
1629         while (!list_empty(&dpm_list)) {
1630                 struct device *dev = to_device(dpm_list.next);
1631
1632                 get_device(dev);
1633                 mutex_unlock(&dpm_list_mtx);
1634
1635                 trace_device_pm_callback_start(dev, "", state.event);
1636                 error = device_prepare(dev, state);
1637                 trace_device_pm_callback_end(dev, error);
1638
1639                 mutex_lock(&dpm_list_mtx);
1640                 if (error) {
1641                         if (error == -EAGAIN) {
1642                                 put_device(dev);
1643                                 error = 0;
1644                                 continue;
1645                         }
1646                         printk(KERN_INFO "PM: Device %s not prepared "
1647                                 "for power transition: code %d\n",
1648                                 dev_name(dev), error);
1649                         put_device(dev);
1650                         break;
1651                 }
1652                 dev->power.is_prepared = true;
1653                 if (!list_empty(&dev->power.entry))
1654                         list_move_tail(&dev->power.entry, &dpm_prepared_list);
1655                 put_device(dev);
1656         }
1657         mutex_unlock(&dpm_list_mtx);
1658         trace_suspend_resume(TPS("dpm_prepare"), state.event, false);
1659         return error;
1660 }
1661
1662 /**
1663  * dpm_suspend_start - Prepare devices for PM transition and suspend them.
1664  * @state: PM transition of the system being carried out.
1665  *
1666  * Prepare all non-sysdev devices for system PM transition and execute "suspend"
1667  * callbacks for them.
1668  */
1669 int dpm_suspend_start(pm_message_t state)
1670 {
1671         int error;
1672
1673         error = dpm_prepare(state);
1674         if (error) {
1675                 suspend_stats.failed_prepare++;
1676                 dpm_save_failed_step(SUSPEND_PREPARE);
1677         } else
1678                 error = dpm_suspend(state);
1679         return error;
1680 }
1681 EXPORT_SYMBOL_GPL(dpm_suspend_start);
1682
1683 void __suspend_report_result(const char *function, void *fn, int ret)
1684 {
1685         if (ret)
1686                 printk(KERN_ERR "%s(): %pF returns %d\n", function, fn, ret);
1687 }
1688 EXPORT_SYMBOL_GPL(__suspend_report_result);
1689
1690 /**
1691  * device_pm_wait_for_dev - Wait for suspend/resume of a device to complete.
1692  * @dev: Device to wait for.
1693  * @subordinate: Device that needs to wait for @dev.
1694  */
1695 int device_pm_wait_for_dev(struct device *subordinate, struct device *dev)
1696 {
1697         dpm_wait(dev, subordinate->power.async_suspend);
1698         return async_error;
1699 }
1700 EXPORT_SYMBOL_GPL(device_pm_wait_for_dev);
1701
1702 /**
1703  * dpm_for_each_dev - device iterator.
1704  * @data: data for the callback.
1705  * @fn: function to be called for each device.
1706  *
1707  * Iterate over devices in dpm_list, and call @fn for each device,
1708  * passing it @data.
1709  */
1710 void dpm_for_each_dev(void *data, void (*fn)(struct device *, void *))
1711 {
1712         struct device *dev;
1713
1714         if (!fn)
1715                 return;
1716
1717         device_pm_lock();
1718         list_for_each_entry(dev, &dpm_list, power.entry)
1719                 fn(dev, data);
1720         device_pm_unlock();
1721 }
1722 EXPORT_SYMBOL_GPL(dpm_for_each_dev);