drivers/base/power/main.c

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