drivers/base/power/main.c

   1 /*
   2  * drivers/base/power/main.c - Where the driver meets power management.
   3  *
   4  * Copyright (c) 2003 Patrick Mochel
   5  * Copyright (c) 2003 Open Source Development Lab
   6  *
   7  * This file is released under the GPLv2
   8  *
   9  *
  10  * The driver model core calls device_pm_add() when a device is registered.
  11  * This will initialize the embedded device_pm_info object in the device
  12  * and add it to the list of power-controlled devices. sysfs entries for
  13  * controlling device power management will also be added.
  14  *
  15  * A separate list is used for keeping track of power info, because the power
  16  * domain dependencies may differ from the ancestral dependencies that the
  17  * subsystem list maintains.
  18  */
  19
  20 #include <linux/device.h>
  21 #include <linux/kallsyms.h>
  22 #include <linux/export.h>
  23 #include <linux/mutex.h>
  24 #include <linux/pm.h>
  25 #include <linux/pm_runtime.h>
  26 #include <linux/resume-trace.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/sched.h>
  29 #include <linux/async.h>
  30 #include <linux/suspend.h>
  31 #include <linux/cpuidle.h>
  32 #include "../base.h"
  33 #include "power.h"
  34
  35 typedef int (*pm_callback_t)(struct device *);
  36
  37 /*
  38  * The entries in the dpm_list list are in a depth first order, simply
  39  * because children are guaranteed to be discovered after parents, and
  40  * are inserted at the back of the list on discovery.
  41  *
  42  * Since device_pm_add() may be called with a device lock held,
  43  * we must never try to acquire a device lock while holding
  44  * dpm_list_mutex.
  45  */
  46
  47 LIST_HEAD(dpm_list);
  48 static LIST_HEAD(dpm_prepared_list);
  49 static LIST_HEAD(dpm_suspended_list);
  50 static LIST_HEAD(dpm_late_early_list);
  51 static LIST_HEAD(dpm_noirq_list);
  52
  53 struct suspend_stats suspend_stats;
  54 static DEFINE_MUTEX(dpm_list_mtx);
  55 static pm_message_t pm_transition;
  56
  57 static int async_error;
  58
  59 /**
  60  * device_pm_sleep_init - Initialize system suspend-related device fields.
  61  * @dev: Device object being initialized.
  62  */
  63 void device_pm_sleep_init(struct device *dev)
  64 {
  65         dev->power.is_prepared = false;
  66         dev->power.is_suspended = false;
  67         init_completion(&dev->power.completion);
  68         complete_all(&dev->power.completion);
  69         dev->power.wakeup = NULL;
  70         INIT_LIST_HEAD(&dev->power.entry);
  71 }
  72
  73 /**
  74  * device_pm_lock - Lock the list of active devices used by the PM core.
  75  */
  76 void device_pm_lock(void)
  77 {
  78         mutex_lock(&dpm_list_mtx);
  79 }
  80
  81 /**
  82  * device_pm_unlock - Unlock the list of active devices used by the PM core.
  83  */
  84 void device_pm_unlock(void)
  85 {
  86         mutex_unlock(&dpm_list_mtx);
  87 }
  88
  89 /**
  90  * device_pm_add - Add a device to the PM core's list of active devices.
  91  * @dev: Device to add to the list.
  92  */
  93 void device_pm_add(struct device *dev)
  94 {
  95         pr_debug("PM: Adding info for %s:%s\n",
  96                  dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
  97         mutex_lock(&dpm_list_mtx);
  98         if (dev->parent && dev->parent->power.is_prepared)
  99                 dev_warn(dev, "parent %s should not be sleeping\n",
 100                         dev_name(dev->parent));
 101         list_add_tail(&dev->power.entry, &dpm_list);
 102         dev_pm_qos_constraints_init(dev);
 103         mutex_unlock(&dpm_list_mtx);
 104 }
 105
 106 /**
 107  * device_pm_remove - Remove a device from the PM core's list of active devices.
 108  * @dev: Device to be removed from the list.
 109  */
 110 void device_pm_remove(struct device *dev)
 111 {
 112         pr_debug("PM: Removing info for %s:%s\n",
 113                  dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
 114         complete_all(&dev->power.completion);
 115         mutex_lock(&dpm_list_mtx);
 116         dev_pm_qos_constraints_destroy(dev);
 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         return error;
 517 }
 518
 519 /**
 520  * dpm_resume_early - Execute "early resume" callbacks for all devices.
 521  * @state: PM transition of the system being carried out.
 522  */
 523 static void dpm_resume_early(pm_message_t state)
 524 {
 525         ktime_t starttime = ktime_get();
 526
 527         mutex_lock(&dpm_list_mtx);
 528         while (!list_empty(&dpm_late_early_list)) {
 529                 struct device *dev = to_device(dpm_late_early_list.next);
 530                 int error;
 531
 532                 get_device(dev);
 533                 list_move_tail(&dev->power.entry, &dpm_suspended_list);
 534                 mutex_unlock(&dpm_list_mtx);
 535
 536                 error = device_resume_early(dev, state);
 537                 if (error) {
 538                         suspend_stats.failed_resume_early++;
 539                         dpm_save_failed_step(SUSPEND_RESUME_EARLY);
 540                         dpm_save_failed_dev(dev_name(dev));
 541                         pm_dev_err(dev, state, " early", error);
 542                 }
 543
 544                 mutex_lock(&dpm_list_mtx);
 545                 put_device(dev);
 546         }
 547         mutex_unlock(&dpm_list_mtx);
 548         dpm_show_time(starttime, state, "early");
 549 }
 550
 551 /**
 552  * dpm_resume_start - Execute "noirq" and "early" device callbacks.
 553  * @state: PM transition of the system being carried out.
 554  */
 555 void dpm_resume_start(pm_message_t state)
 556 {
 557         dpm_resume_noirq(state);
 558         dpm_resume_early(state);
 559 }
 560 EXPORT_SYMBOL_GPL(dpm_resume_start);
 561
 562 /**
 563  * device_resume - Execute "resume" callbacks for given device.
 564  * @dev: Device to handle.
 565  * @state: PM transition of the system being carried out.
 566  * @async: If true, the device is being resumed asynchronously.
 567  */
 568 static int device_resume(struct device *dev, pm_message_t state, bool async)
 569 {
 570         pm_callback_t callback = NULL;
 571         char *info = NULL;
 572         int error = 0;
 573         bool put = false;
 574
 575         TRACE_DEVICE(dev);
 576         TRACE_RESUME(0);
 577
 578         if (dev->power.syscore)
 579                 goto Complete;
 580
 581         dpm_wait(dev->parent, async);
 582         device_lock(dev);
 583
 584         /*
 585          * This is a fib.  But we'll allow new children to be added below
 586          * a resumed device, even if the device hasn't been completed yet.
 587          */
 588         dev->power.is_prepared = false;
 589
 590         if (!dev->power.is_suspended)
 591                 goto Unlock;
 592
 593         pm_runtime_enable(dev);
 594         put = true;
 595
 596         if (dev->pm_domain) {
 597                 info = "power domain ";
 598                 callback = pm_op(&dev->pm_domain->ops, state);
 599                 goto Driver;
 600         }
 601
 602         if (dev->type && dev->type->pm) {
 603                 info = "type ";
 604                 callback = pm_op(dev->type->pm, state);
 605                 goto Driver;
 606         }
 607
 608         if (dev->class) {
 609                 if (dev->class->pm) {
 610                         info = "class ";
 611                         callback = pm_op(dev->class->pm, state);
 612                         goto Driver;
 613                 } else if (dev->class->resume) {
 614                         info = "legacy class ";
 615                         callback = dev->class->resume;
 616                         goto End;
 617                 }
 618         }
 619
 620         if (dev->bus) {
 621                 if (dev->bus->pm) {
 622                         info = "bus ";
 623                         callback = pm_op(dev->bus->pm, state);
 624                 } else if (dev->bus->resume) {
 625                         info = "legacy bus ";
 626                         callback = dev->bus->resume;
 627                         goto End;
 628                 }
 629         }
 630
 631  Driver:
 632         if (!callback && dev->driver && dev->driver->pm) {
 633                 info = "driver ";
 634                 callback = pm_op(dev->driver->pm, state);
 635         }
 636
 637  End:
 638         error = dpm_run_callback(callback, dev, state, info);
 639         dev->power.is_suspended = false;
 640
 641  Unlock:
 642         device_unlock(dev);
 643
 644  Complete:
 645         complete_all(&dev->power.completion);
 646
 647         TRACE_RESUME(error);
 648
 649         if (put)
 650                 pm_runtime_put_sync(dev);
 651
 652         return error;
 653 }
 654
 655 static void async_resume(void *data, async_cookie_t cookie)
 656 {
 657         struct device *dev = (struct device *)data;
 658         int error;
 659
 660         error = device_resume(dev, pm_transition, true);
 661         if (error)
 662                 pm_dev_err(dev, pm_transition, " async", error);
 663         put_device(dev);
 664 }
 665
 666 static bool is_async(struct device *dev)
 667 {
 668         return dev->power.async_suspend && pm_async_enabled
 669                 && !pm_trace_is_enabled();
 670 }
 671
 672 /**
 673  * dpm_resume - Execute "resume" callbacks for non-sysdev devices.
 674  * @state: PM transition of the system being carried out.
 675  *
 676  * Execute the appropriate "resume" callback for all devices whose status
 677  * indicates that they are suspended.
 678  */
 679 void dpm_resume(pm_message_t state)
 680 {
 681         struct device *dev;
 682         ktime_t starttime = ktime_get();
 683
 684         might_sleep();
 685
 686         mutex_lock(&dpm_list_mtx);
 687         pm_transition = state;
 688         async_error = 0;
 689
 690         list_for_each_entry(dev, &dpm_suspended_list, power.entry) {
 691                 INIT_COMPLETION(dev->power.completion);
 692                 if (is_async(dev)) {
 693                         get_device(dev);
 694                         async_schedule(async_resume, dev);
 695                 }
 696         }
 697
 698         while (!list_empty(&dpm_suspended_list)) {
 699                 dev = to_device(dpm_suspended_list.next);
 700                 get_device(dev);
 701                 if (!is_async(dev)) {
 702                         int error;
 703
 704                         mutex_unlock(&dpm_list_mtx);
 705
 706                         error = device_resume(dev, state, false);
 707                         if (error) {
 708                                 suspend_stats.failed_resume++;
 709                                 dpm_save_failed_step(SUSPEND_RESUME);
 710                                 dpm_save_failed_dev(dev_name(dev));
 711                                 pm_dev_err(dev, state, "", error);
 712                         }
 713
 714                         mutex_lock(&dpm_list_mtx);
 715                 }
 716                 if (!list_empty(&dev->power.entry))
 717                         list_move_tail(&dev->power.entry, &dpm_prepared_list);
 718                 put_device(dev);
 719         }
 720         mutex_unlock(&dpm_list_mtx);
 721         async_synchronize_full();
 722         dpm_show_time(starttime, state, NULL);
 723 }
 724
 725 /**
 726  * device_complete - Complete a PM transition for given device.
 727  * @dev: Device to handle.
 728  * @state: PM transition of the system being carried out.
 729  */
 730 static void device_complete(struct device *dev, pm_message_t state)
 731 {
 732         void (*callback)(struct device *) = NULL;
 733         char *info = NULL;
 734
 735         if (dev->power.syscore)
 736                 return;
 737
 738         device_lock(dev);
 739
 740         if (dev->pm_domain) {
 741                 info = "completing power domain ";
 742                 callback = dev->pm_domain->ops.complete;
 743         } else if (dev->type && dev->type->pm) {
 744                 info = "completing type ";
 745                 callback = dev->type->pm->complete;
 746         } else if (dev->class && dev->class->pm) {
 747                 info = "completing class ";
 748                 callback = dev->class->pm->complete;
 749         } else if (dev->bus && dev->bus->pm) {
 750                 info = "completing bus ";
 751                 callback = dev->bus->pm->complete;
 752         }
 753
 754         if (!callback && dev->driver && dev->driver->pm) {
 755                 info = "completing driver ";
 756                 callback = dev->driver->pm->complete;
 757         }
 758
 759         if (callback) {
 760                 pm_dev_dbg(dev, state, info);
 761                 callback(dev);
 762         }
 763
 764         device_unlock(dev);
 765 }
 766
 767 /**
 768  * dpm_complete - Complete a PM transition for all non-sysdev devices.
 769  * @state: PM transition of the system being carried out.
 770  *
 771  * Execute the ->complete() callbacks for all devices whose PM status is not
 772  * DPM_ON (this allows new devices to be registered).
 773  */
 774 void dpm_complete(pm_message_t state)
 775 {
 776         struct list_head list;
 777
 778         might_sleep();
 779
 780         INIT_LIST_HEAD(&list);
 781         mutex_lock(&dpm_list_mtx);
 782         while (!list_empty(&dpm_prepared_list)) {
 783                 struct device *dev = to_device(dpm_prepared_list.prev);
 784
 785                 get_device(dev);
 786                 dev->power.is_prepared = false;
 787                 list_move(&dev->power.entry, &list);
 788                 mutex_unlock(&dpm_list_mtx);
 789
 790                 device_complete(dev, state);
 791
 792                 mutex_lock(&dpm_list_mtx);
 793                 put_device(dev);
 794         }
 795         list_splice(&list, &dpm_list);
 796         mutex_unlock(&dpm_list_mtx);
 797 }
 798
 799 /**
 800  * dpm_resume_end - Execute "resume" callbacks and complete system transition.
 801  * @state: PM transition of the system being carried out.
 802  *
 803  * Execute "resume" callbacks for all devices and complete the PM transition of
 804  * the system.
 805  */
 806 void dpm_resume_end(pm_message_t state)
 807 {
 808         dpm_resume(state);
 809         dpm_complete(state);
 810 }
 811 EXPORT_SYMBOL_GPL(dpm_resume_end);
 812
 813
 814 /*------------------------- Suspend routines -------------------------*/
 815
 816 /**
 817  * resume_event - Return a "resume" message for given "suspend" sleep state.
 818  * @sleep_state: PM message representing a sleep state.
 819  *
 820  * Return a PM message representing the resume event corresponding to given
 821  * sleep state.
 822  */
 823 static pm_message_t resume_event(pm_message_t sleep_state)
 824 {
 825         switch (sleep_state.event) {
 826         case PM_EVENT_SUSPEND:
 827                 return PMSG_RESUME;
 828         case PM_EVENT_FREEZE:
 829         case PM_EVENT_QUIESCE:
 830                 return PMSG_RECOVER;
 831         case PM_EVENT_HIBERNATE:
 832                 return PMSG_RESTORE;
 833         }
 834         return PMSG_ON;
 835 }
 836
 837 /**
 838  * device_suspend_noirq - Execute a "late suspend" callback for given device.
 839  * @dev: Device to handle.
 840  * @state: PM transition of the system being carried out.
 841  *
 842  * The driver of @dev will not receive interrupts while this function is being
 843  * executed.
 844  */
 845 static int device_suspend_noirq(struct device *dev, pm_message_t state)
 846 {
 847         pm_callback_t callback = NULL;
 848         char *info = NULL;
 849
 850         if (dev->power.syscore)
 851                 return 0;
 852
 853         if (dev->pm_domain) {
 854                 info = "noirq power domain ";
 855                 callback = pm_noirq_op(&dev->pm_domain->ops, state);
 856         } else if (dev->type && dev->type->pm) {
 857                 info = "noirq type ";
 858                 callback = pm_noirq_op(dev->type->pm, state);
 859         } else if (dev->class && dev->class->pm) {
 860                 info = "noirq class ";
 861                 callback = pm_noirq_op(dev->class->pm, state);
 862         } else if (dev->bus && dev->bus->pm) {
 863                 info = "noirq bus ";
 864                 callback = pm_noirq_op(dev->bus->pm, state);
 865         }
 866
 867         if (!callback && dev->driver && dev->driver->pm) {
 868                 info = "noirq driver ";
 869                 callback = pm_noirq_op(dev->driver->pm, state);
 870         }
 871
 872         return dpm_run_callback(callback, dev, state, info);
 873 }
 874
 875 /**
 876  * dpm_suspend_noirq - Execute "noirq suspend" callbacks for all devices.
 877  * @state: PM transition of the system being carried out.
 878  *
 879  * Prevent device drivers from receiving interrupts and call the "noirq" suspend
 880  * handlers for all non-sysdev devices.
 881  */
 882 static int dpm_suspend_noirq(pm_message_t state)
 883 {
 884         ktime_t starttime = ktime_get();
 885         int error = 0;
 886
 887         cpuidle_pause();
 888         suspend_device_irqs();
 889         mutex_lock(&dpm_list_mtx);
 890         while (!list_empty(&dpm_late_early_list)) {
 891                 struct device *dev = to_device(dpm_late_early_list.prev);
 892
 893                 get_device(dev);
 894                 mutex_unlock(&dpm_list_mtx);
 895
 896                 error = device_suspend_noirq(dev, state);
 897
 898                 mutex_lock(&dpm_list_mtx);
 899                 if (error) {
 900                         pm_dev_err(dev, state, " noirq", error);
 901                         suspend_stats.failed_suspend_noirq++;
 902                         dpm_save_failed_step(SUSPEND_SUSPEND_NOIRQ);
 903                         dpm_save_failed_dev(dev_name(dev));
 904                         put_device(dev);
 905                         break;
 906                 }
 907                 if (!list_empty(&dev->power.entry))
 908                         list_move(&dev->power.entry, &dpm_noirq_list);
 909                 put_device(dev);
 910
 911                 if (pm_wakeup_pending()) {
 912                         error = -EBUSY;
 913                         break;
 914                 }
 915         }
 916         mutex_unlock(&dpm_list_mtx);
 917         if (error)
 918                 dpm_resume_noirq(resume_event(state));
 919         else
 920                 dpm_show_time(starttime, state, "noirq");
 921         return error;
 922 }
 923
 924 /**
 925  * device_suspend_late - Execute a "late suspend" callback for given device.
 926  * @dev: Device to handle.
 927  * @state: PM transition of the system being carried out.
 928  *
 929  * Runtime PM is disabled for @dev while this function is being executed.
 930  */
 931 static int device_suspend_late(struct device *dev, pm_message_t state)
 932 {
 933         pm_callback_t callback = NULL;
 934         char *info = NULL;
 935
 936         if (dev->power.syscore)
 937                 return 0;
 938
 939         if (dev->pm_domain) {
 940                 info = "late power domain ";
 941                 callback = pm_late_early_op(&dev->pm_domain->ops, state);
 942         } else if (dev->type && dev->type->pm) {
 943                 info = "late type ";
 944                 callback = pm_late_early_op(dev->type->pm, state);
 945         } else if (dev->class && dev->class->pm) {
 946                 info = "late class ";
 947                 callback = pm_late_early_op(dev->class->pm, state);
 948         } else if (dev->bus && dev->bus->pm) {
 949                 info = "late bus ";
 950                 callback = pm_late_early_op(dev->bus->pm, state);
 951         }
 952
 953         if (!callback && dev->driver && dev->driver->pm) {
 954                 info = "late driver ";
 955                 callback = pm_late_early_op(dev->driver->pm, state);
 956         }
 957
 958         return dpm_run_callback(callback, dev, state, info);
 959 }
 960
 961 /**
 962  * dpm_suspend_late - Execute "late suspend" callbacks for all devices.
 963  * @state: PM transition of the system being carried out.
 964  */
 965 static int dpm_suspend_late(pm_message_t state)
 966 {
 967         ktime_t starttime = ktime_get();
 968         int error = 0;
 969
 970         mutex_lock(&dpm_list_mtx);
 971         while (!list_empty(&dpm_suspended_list)) {
 972                 struct device *dev = to_device(dpm_suspended_list.prev);
 973
 974                 get_device(dev);
 975                 mutex_unlock(&dpm_list_mtx);
 976
 977                 error = device_suspend_late(dev, state);
 978
 979                 mutex_lock(&dpm_list_mtx);
 980                 if (error) {
 981                         pm_dev_err(dev, state, " late", error);
 982                         suspend_stats.failed_suspend_late++;
 983                         dpm_save_failed_step(SUSPEND_SUSPEND_LATE);
 984                         dpm_save_failed_dev(dev_name(dev));
 985                         put_device(dev);
 986                         break;
 987                 }
 988                 if (!list_empty(&dev->power.entry))
 989                         list_move(&dev->power.entry, &dpm_late_early_list);
 990                 put_device(dev);
 991
 992                 if (pm_wakeup_pending()) {
 993                         error = -EBUSY;
 994                         break;
 995                 }
 996         }
 997         mutex_unlock(&dpm_list_mtx);
 998         if (error)
 999                 dpm_resume_early(resume_event(state));
1000         else
1001                 dpm_show_time(starttime, state, "late");
1002
1003         return error;
1004 }
1005
1006 /**
1007  * dpm_suspend_end - Execute "late" and "noirq" device suspend callbacks.
1008  * @state: PM transition of the system being carried out.
1009  */
1010 int dpm_suspend_end(pm_message_t state)
1011 {
1012         int error = dpm_suspend_late(state);
1013         if (error)
1014                 return error;
1015
1016         error = dpm_suspend_noirq(state);
1017         if (error) {
1018                 dpm_resume_early(state);
1019                 return error;
1020         }
1021
1022         return 0;
1023 }
1024 EXPORT_SYMBOL_GPL(dpm_suspend_end);
1025
1026 /**
1027  * legacy_suspend - Execute a legacy (bus or class) suspend callback for device.
1028  * @dev: Device to suspend.
1029  * @state: PM transition of the system being carried out.
1030  * @cb: Suspend callback to execute.
1031  */
1032 static int legacy_suspend(struct device *dev, pm_message_t state,
1033                           int (*cb)(struct device *dev, pm_message_t state))
1034 {
1035         int error;
1036         ktime_t calltime;
1037
1038         calltime = initcall_debug_start(dev);
1039
1040         error = cb(dev, state);
1041         suspend_report_result(cb, error);
1042
1043         initcall_debug_report(dev, calltime, error);
1044
1045         return error;
1046 }
1047
1048 /**
1049  * device_suspend - Execute "suspend" callbacks for given device.
1050  * @dev: Device to handle.
1051  * @state: PM transition of the system being carried out.
1052  * @async: If true, the device is being suspended asynchronously.
1053  */
1054 static int __device_suspend(struct device *dev, pm_message_t state, bool async)
1055 {
1056         pm_callback_t callback = NULL;
1057         char *info = NULL;
1058         int error = 0;
1059
1060         dpm_wait_for_children(dev, async);
1061
1062         if (async_error)
1063                 goto Complete;
1064
1065         pm_runtime_get_noresume(dev);
1066         if (pm_runtime_barrier(dev) && device_may_wakeup(dev))
1067                 pm_wakeup_event(dev, 0);
1068
1069         if (pm_wakeup_pending()) {
1070                 pm_runtime_put_sync(dev);
1071                 async_error = -EBUSY;
1072                 goto Complete;
1073         }
1074
1075         if (dev->power.syscore)
1076                 goto Complete;
1077
1078         device_lock(dev);
1079
1080         if (dev->pm_domain) {
1081                 info = "power domain ";
1082                 callback = pm_op(&dev->pm_domain->ops, state);
1083                 goto Run;
1084         }
1085
1086         if (dev->type && dev->type->pm) {
1087                 info = "type ";
1088                 callback = pm_op(dev->type->pm, state);
1089                 goto Run;
1090         }
1091
1092         if (dev->class) {
1093                 if (dev->class->pm) {
1094                         info = "class ";
1095                         callback = pm_op(dev->class->pm, state);
1096                         goto Run;
1097                 } else if (dev->class->suspend) {
1098                         pm_dev_dbg(dev, state, "legacy class ");
1099                         error = legacy_suspend(dev, state, dev->class->suspend);
1100                         goto End;
1101                 }
1102         }
1103
1104         if (dev->bus) {
1105                 if (dev->bus->pm) {
1106                         info = "bus ";
1107                         callback = pm_op(dev->bus->pm, state);
1108                 } else if (dev->bus->suspend) {
1109                         pm_dev_dbg(dev, state, "legacy bus ");
1110                         error = legacy_suspend(dev, state, dev->bus->suspend);
1111                         goto End;
1112                 }
1113         }
1114
1115  Run:
1116         if (!callback && dev->driver && dev->driver->pm) {
1117                 info = "driver ";
1118                 callback = pm_op(dev->driver->pm, state);
1119         }
1120
1121         error = dpm_run_callback(callback, dev, state, info);
1122
1123  End:
1124         if (!error) {
1125                 dev->power.is_suspended = true;
1126                 if (dev->power.wakeup_path
1127                     && dev->parent && !dev->parent->power.ignore_children)
1128                         dev->parent->power.wakeup_path = true;
1129         }
1130
1131         device_unlock(dev);
1132
1133  Complete:
1134         complete_all(&dev->power.completion);
1135
1136         if (error) {
1137                 pm_runtime_put_sync(dev);
1138                 async_error = error;
1139         } else if (dev->power.is_suspended) {
1140                 __pm_runtime_disable(dev, false);
1141         }
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         mutex_lock(&dpm_list_mtx);
1185         pm_transition = state;
1186         async_error = 0;
1187         while (!list_empty(&dpm_prepared_list)) {
1188                 struct device *dev = to_device(dpm_prepared_list.prev);
1189
1190                 get_device(dev);
1191                 mutex_unlock(&dpm_list_mtx);
1192
1193                 error = device_suspend(dev);
1194
1195                 mutex_lock(&dpm_list_mtx);
1196                 if (error) {
1197                         pm_dev_err(dev, state, "", error);
1198                         dpm_save_failed_dev(dev_name(dev));
1199                         put_device(dev);
1200                         break;
1201                 }
1202                 if (!list_empty(&dev->power.entry))
1203                         list_move(&dev->power.entry, &dpm_suspended_list);
1204                 put_device(dev);
1205                 if (async_error)
1206                         break;
1207         }
1208         mutex_unlock(&dpm_list_mtx);
1209         async_synchronize_full();
1210         if (!error)
1211                 error = async_error;
1212         if (error) {
1213                 suspend_stats.failed_suspend++;
1214                 dpm_save_failed_step(SUSPEND_SUSPEND);
1215         } else
1216                 dpm_show_time(starttime, state, NULL);
1217         return error;
1218 }
1219
1220 /**
1221  * device_prepare - Prepare a device for system power transition.
1222  * @dev: Device to handle.
1223  * @state: PM transition of the system being carried out.
1224  *
1225  * Execute the ->prepare() callback(s) for given device.  No new children of the
1226  * device may be registered after this function has returned.
1227  */
1228 static int device_prepare(struct device *dev, pm_message_t state)
1229 {
1230         int (*callback)(struct device *) = NULL;
1231         char *info = NULL;
1232         int error = 0;
1233
1234         if (dev->power.syscore)
1235                 return 0;
1236
1237         device_lock(dev);
1238
1239         dev->power.wakeup_path = device_may_wakeup(dev);
1240
1241         if (dev->pm_domain) {
1242                 info = "preparing power domain ";
1243                 callback = dev->pm_domain->ops.prepare;
1244         } else if (dev->type && dev->type->pm) {
1245                 info = "preparing type ";
1246                 callback = dev->type->pm->prepare;
1247         } else if (dev->class && dev->class->pm) {
1248                 info = "preparing class ";
1249                 callback = dev->class->pm->prepare;
1250         } else if (dev->bus && dev->bus->pm) {
1251                 info = "preparing bus ";
1252                 callback = dev->bus->pm->prepare;
1253         }
1254
1255         if (!callback && dev->driver && dev->driver->pm) {
1256                 info = "preparing driver ";
1257                 callback = dev->driver->pm->prepare;
1258         }
1259
1260         if (callback) {
1261                 error = callback(dev);
1262                 suspend_report_result(callback, error);
1263         }
1264
1265         device_unlock(dev);
1266
1267         return error;
1268 }
1269
1270 /**
1271  * dpm_prepare - Prepare all non-sysdev devices for a system PM transition.
1272  * @state: PM transition of the system being carried out.
1273  *
1274  * Execute the ->prepare() callback(s) for all devices.
1275  */
1276 int dpm_prepare(pm_message_t state)
1277 {
1278         int error = 0;
1279
1280         might_sleep();
1281
1282         mutex_lock(&dpm_list_mtx);
1283         while (!list_empty(&dpm_list)) {
1284                 struct device *dev = to_device(dpm_list.next);
1285
1286                 get_device(dev);
1287                 mutex_unlock(&dpm_list_mtx);
1288
1289                 error = device_prepare(dev, state);
1290
1291                 mutex_lock(&dpm_list_mtx);
1292                 if (error) {
1293                         if (error == -EAGAIN) {
1294                                 put_device(dev);
1295                                 error = 0;
1296                                 continue;
1297                         }
1298                         printk(KERN_INFO "PM: Device %s not prepared "
1299                                 "for power transition: code %d\n",
1300                                 dev_name(dev), error);
1301                         put_device(dev);
1302                         break;
1303                 }
1304                 dev->power.is_prepared = true;
1305                 if (!list_empty(&dev->power.entry))
1306                         list_move_tail(&dev->power.entry, &dpm_prepared_list);
1307                 put_device(dev);
1308         }
1309         mutex_unlock(&dpm_list_mtx);
1310         return error;
1311 }
1312
1313 /**
1314  * dpm_suspend_start - Prepare devices for PM transition and suspend them.
1315  * @state: PM transition of the system being carried out.
1316  *
1317  * Prepare all non-sysdev devices for system PM transition and execute "suspend"
1318  * callbacks for them.
1319  */
1320 int dpm_suspend_start(pm_message_t state)
1321 {
1322         int error;
1323
1324         error = dpm_prepare(state);
1325         if (error) {
1326                 suspend_stats.failed_prepare++;
1327                 dpm_save_failed_step(SUSPEND_PREPARE);
1328         } else
1329                 error = dpm_suspend(state);
1330         return error;
1331 }
1332 EXPORT_SYMBOL_GPL(dpm_suspend_start);
1333
1334 void __suspend_report_result(const char *function, void *fn, int ret)
1335 {
1336         if (ret)
1337                 printk(KERN_ERR "%s(): %pF returns %d\n", function, fn, ret);
1338 }
1339 EXPORT_SYMBOL_GPL(__suspend_report_result);
1340
1341 /**
1342  * device_pm_wait_for_dev - Wait for suspend/resume of a device to complete.
1343  * @dev: Device to wait for.
1344  * @subordinate: Device that needs to wait for @dev.
1345  */
1346 int device_pm_wait_for_dev(struct device *subordinate, struct device *dev)
1347 {
1348         dpm_wait(dev, subordinate->power.async_suspend);
1349         return async_error;
1350 }
1351 EXPORT_SYMBOL_GPL(device_pm_wait_for_dev);
1352
1353 /**
1354  * dpm_for_each_dev - device iterator.
1355  * @data: data for the callback.
1356  * @fn: function to be called for each device.
1357  *
1358  * Iterate over devices in dpm_list, and call @fn for each device,
1359  * passing it @data.
1360  */
1361 void dpm_for_each_dev(void *data, void (*fn)(struct device *, void *))
1362 {
1363         struct device *dev;
1364
1365         if (!fn)
1366                 return;
1367
1368         device_pm_lock();
1369         list_for_each_entry(dev, &dpm_list, power.entry)
1370                 fn(dev, data);
1371         device_pm_unlock();
1372 }
1373 EXPORT_SYMBOL_GPL(dpm_for_each_dev);