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
 574         TRACE_DEVICE(dev);
 575         TRACE_RESUME(0);
 576
 577         if (dev->power.syscore)
 578                 goto Complete;
 579
 580         dpm_wait(dev->parent, async);
 581         device_lock(dev);
 582
 583         /*
 584          * This is a fib.  But we'll allow new children to be added below
 585          * a resumed device, even if the device hasn't been completed yet.
 586          */
 587         dev->power.is_prepared = false;
 588
 589         if (!dev->power.is_suspended)
 590                 goto Unlock;
 591
 592         pm_runtime_enable(dev);
 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
 720 /**
 721  * device_complete - Complete a PM transition for given device.
 722  * @dev: Device to handle.
 723  * @state: PM transition of the system being carried out.
 724  */
 725 static void device_complete(struct device *dev, pm_message_t state)
 726 {
 727         void (*callback)(struct device *) = NULL;
 728         char *info = NULL;
 729
 730         if (dev->power.syscore)
 731                 return;
 732
 733         device_lock(dev);
 734
 735         if (dev->pm_domain) {
 736                 info = "completing power domain ";
 737                 callback = dev->pm_domain->ops.complete;
 738         } else if (dev->type && dev->type->pm) {
 739                 info = "completing type ";
 740                 callback = dev->type->pm->complete;
 741         } else if (dev->class && dev->class->pm) {
 742                 info = "completing class ";
 743                 callback = dev->class->pm->complete;
 744         } else if (dev->bus && dev->bus->pm) {
 745                 info = "completing bus ";
 746                 callback = dev->bus->pm->complete;
 747         }
 748
 749         if (!callback && dev->driver && dev->driver->pm) {
 750                 info = "completing driver ";
 751                 callback = dev->driver->pm->complete;
 752         }
 753
 754         if (callback) {
 755                 pm_dev_dbg(dev, state, info);
 756                 callback(dev);
 757         }
 758
 759         device_unlock(dev);
 760
 761         pm_runtime_put_sync(dev);
 762 }
 763
 764 /**
 765  * dpm_complete - Complete a PM transition for all non-sysdev devices.
 766  * @state: PM transition of the system being carried out.
 767  *
 768  * Execute the ->complete() callbacks for all devices whose PM status is not
 769  * DPM_ON (this allows new devices to be registered).
 770  */
 771 void dpm_complete(pm_message_t state)
 772 {
 773         struct list_head list;
 774
 775         might_sleep();
 776
 777         INIT_LIST_HEAD(&list);
 778         mutex_lock(&dpm_list_mtx);
 779         while (!list_empty(&dpm_prepared_list)) {
 780                 struct device *dev = to_device(dpm_prepared_list.prev);
 781
 782                 get_device(dev);
 783                 dev->power.is_prepared = false;
 784                 list_move(&dev->power.entry, &list);
 785                 mutex_unlock(&dpm_list_mtx);
 786
 787                 device_complete(dev, state);
 788
 789                 mutex_lock(&dpm_list_mtx);
 790                 put_device(dev);
 791         }
 792         list_splice(&list, &dpm_list);
 793         mutex_unlock(&dpm_list_mtx);
 794 }
 795
 796 /**
 797  * dpm_resume_end - Execute "resume" callbacks and complete system transition.
 798  * @state: PM transition of the system being carried out.
 799  *
 800  * Execute "resume" callbacks for all devices and complete the PM transition of
 801  * the system.
 802  */
 803 void dpm_resume_end(pm_message_t state)
 804 {
 805         dpm_resume(state);
 806         dpm_complete(state);
 807 }
 808 EXPORT_SYMBOL_GPL(dpm_resume_end);
 809
 810
 811 /*------------------------- Suspend routines -------------------------*/
 812
 813 /**
 814  * resume_event - Return a "resume" message for given "suspend" sleep state.
 815  * @sleep_state: PM message representing a sleep state.
 816  *
 817  * Return a PM message representing the resume event corresponding to given
 818  * sleep state.
 819  */
 820 static pm_message_t resume_event(pm_message_t sleep_state)
 821 {
 822         switch (sleep_state.event) {
 823         case PM_EVENT_SUSPEND:
 824                 return PMSG_RESUME;
 825         case PM_EVENT_FREEZE:
 826         case PM_EVENT_QUIESCE:
 827                 return PMSG_RECOVER;
 828         case PM_EVENT_HIBERNATE:
 829                 return PMSG_RESTORE;
 830         }
 831         return PMSG_ON;
 832 }
 833
 834 /**
 835  * device_suspend_noirq - Execute a "late suspend" callback for given device.
 836  * @dev: Device to handle.
 837  * @state: PM transition of the system being carried out.
 838  *
 839  * The driver of @dev will not receive interrupts while this function is being
 840  * executed.
 841  */
 842 static int device_suspend_noirq(struct device *dev, pm_message_t state)
 843 {
 844         pm_callback_t callback = NULL;
 845         char *info = NULL;
 846
 847         if (dev->power.syscore)
 848                 return 0;
 849
 850         if (dev->pm_domain) {
 851                 info = "noirq power domain ";
 852                 callback = pm_noirq_op(&dev->pm_domain->ops, state);
 853         } else if (dev->type && dev->type->pm) {
 854                 info = "noirq type ";
 855                 callback = pm_noirq_op(dev->type->pm, state);
 856         } else if (dev->class && dev->class->pm) {
 857                 info = "noirq class ";
 858                 callback = pm_noirq_op(dev->class->pm, state);
 859         } else if (dev->bus && dev->bus->pm) {
 860                 info = "noirq bus ";
 861                 callback = pm_noirq_op(dev->bus->pm, state);
 862         }
 863
 864         if (!callback && dev->driver && dev->driver->pm) {
 865                 info = "noirq driver ";
 866                 callback = pm_noirq_op(dev->driver->pm, state);
 867         }
 868
 869         return dpm_run_callback(callback, dev, state, info);
 870 }
 871
 872 /**
 873  * dpm_suspend_noirq - Execute "noirq suspend" callbacks for all devices.
 874  * @state: PM transition of the system being carried out.
 875  *
 876  * Prevent device drivers from receiving interrupts and call the "noirq" suspend
 877  * handlers for all non-sysdev devices.
 878  */
 879 static int dpm_suspend_noirq(pm_message_t state)
 880 {
 881         ktime_t starttime = ktime_get();
 882         int error = 0;
 883
 884         cpuidle_pause();
 885         suspend_device_irqs();
 886         mutex_lock(&dpm_list_mtx);
 887         while (!list_empty(&dpm_late_early_list)) {
 888                 struct device *dev = to_device(dpm_late_early_list.prev);
 889
 890                 get_device(dev);
 891                 mutex_unlock(&dpm_list_mtx);
 892
 893                 error = device_suspend_noirq(dev, state);
 894
 895                 mutex_lock(&dpm_list_mtx);
 896                 if (error) {
 897                         pm_dev_err(dev, state, " noirq", error);
 898                         suspend_stats.failed_suspend_noirq++;
 899                         dpm_save_failed_step(SUSPEND_SUSPEND_NOIRQ);
 900                         dpm_save_failed_dev(dev_name(dev));
 901                         put_device(dev);
 902                         break;
 903                 }
 904                 if (!list_empty(&dev->power.entry))
 905                         list_move(&dev->power.entry, &dpm_noirq_list);
 906                 put_device(dev);
 907
 908                 if (pm_wakeup_pending()) {
 909                         error = -EBUSY;
 910                         break;
 911                 }
 912         }
 913         mutex_unlock(&dpm_list_mtx);
 914         if (error)
 915                 dpm_resume_noirq(resume_event(state));
 916         else
 917                 dpm_show_time(starttime, state, "noirq");
 918         return error;
 919 }
 920
 921 /**
 922  * device_suspend_late - Execute a "late suspend" callback for given device.
 923  * @dev: Device to handle.
 924  * @state: PM transition of the system being carried out.
 925  *
 926  * Runtime PM is disabled for @dev while this function is being executed.
 927  */
 928 static int device_suspend_late(struct device *dev, pm_message_t state)
 929 {
 930         pm_callback_t callback = NULL;
 931         char *info = NULL;
 932
 933         if (dev->power.syscore)
 934                 return 0;
 935
 936         if (dev->pm_domain) {
 937                 info = "late power domain ";
 938                 callback = pm_late_early_op(&dev->pm_domain->ops, state);
 939         } else if (dev->type && dev->type->pm) {
 940                 info = "late type ";
 941                 callback = pm_late_early_op(dev->type->pm, state);
 942         } else if (dev->class && dev->class->pm) {
 943                 info = "late class ";
 944                 callback = pm_late_early_op(dev->class->pm, state);
 945         } else if (dev->bus && dev->bus->pm) {
 946                 info = "late bus ";
 947                 callback = pm_late_early_op(dev->bus->pm, state);
 948         }
 949
 950         if (!callback && dev->driver && dev->driver->pm) {
 951                 info = "late driver ";
 952                 callback = pm_late_early_op(dev->driver->pm, state);
 953         }
 954
 955         return dpm_run_callback(callback, dev, state, info);
 956 }
 957
 958 /**
 959  * dpm_suspend_late - Execute "late suspend" callbacks for all devices.
 960  * @state: PM transition of the system being carried out.
 961  */
 962 static int dpm_suspend_late(pm_message_t state)
 963 {
 964         ktime_t starttime = ktime_get();
 965         int error = 0;
 966
 967         mutex_lock(&dpm_list_mtx);
 968         while (!list_empty(&dpm_suspended_list)) {
 969                 struct device *dev = to_device(dpm_suspended_list.prev);
 970
 971                 get_device(dev);
 972                 mutex_unlock(&dpm_list_mtx);
 973
 974                 error = device_suspend_late(dev, state);
 975
 976                 mutex_lock(&dpm_list_mtx);
 977                 if (error) {
 978                         pm_dev_err(dev, state, " late", error);
 979                         suspend_stats.failed_suspend_late++;
 980                         dpm_save_failed_step(SUSPEND_SUSPEND_LATE);
 981                         dpm_save_failed_dev(dev_name(dev));
 982                         put_device(dev);
 983                         break;
 984                 }
 985                 if (!list_empty(&dev->power.entry))
 986                         list_move(&dev->power.entry, &dpm_late_early_list);
 987                 put_device(dev);
 988
 989                 if (pm_wakeup_pending()) {
 990                         error = -EBUSY;
 991                         break;
 992                 }
 993         }
 994         mutex_unlock(&dpm_list_mtx);
 995         if (error)
 996                 dpm_resume_early(resume_event(state));
 997         else
 998                 dpm_show_time(starttime, state, "late");
 999
1000         return error;
1001 }
1002
1003 /**
1004  * dpm_suspend_end - Execute "late" and "noirq" device suspend callbacks.
1005  * @state: PM transition of the system being carried out.
1006  */
1007 int dpm_suspend_end(pm_message_t state)
1008 {
1009         int error = dpm_suspend_late(state);
1010         if (error)
1011                 return error;
1012
1013         error = dpm_suspend_noirq(state);
1014         if (error) {
1015                 dpm_resume_early(resume_event(state));
1016                 return error;
1017         }
1018
1019         return 0;
1020 }
1021 EXPORT_SYMBOL_GPL(dpm_suspend_end);
1022
1023 /**
1024  * legacy_suspend - Execute a legacy (bus or class) suspend callback for device.
1025  * @dev: Device to suspend.
1026  * @state: PM transition of the system being carried out.
1027  * @cb: Suspend callback to execute.
1028  */
1029 static int legacy_suspend(struct device *dev, pm_message_t state,
1030                           int (*cb)(struct device *dev, pm_message_t state))
1031 {
1032         int error;
1033         ktime_t calltime;
1034
1035         calltime = initcall_debug_start(dev);
1036
1037         error = cb(dev, state);
1038         suspend_report_result(cb, error);
1039
1040         initcall_debug_report(dev, calltime, error);
1041
1042         return error;
1043 }
1044
1045 /**
1046  * device_suspend - Execute "suspend" callbacks for given device.
1047  * @dev: Device to handle.
1048  * @state: PM transition of the system being carried out.
1049  * @async: If true, the device is being suspended asynchronously.
1050  */
1051 static int __device_suspend(struct device *dev, pm_message_t state, bool async)
1052 {
1053         pm_callback_t callback = NULL;
1054         char *info = NULL;
1055         int error = 0;
1056
1057         dpm_wait_for_children(dev, async);
1058
1059         if (async_error)
1060                 goto Complete;
1061
1062         /*
1063          * If a device configured to wake up the system from sleep states
1064          * has been suspended at run time and there's a resume request pending
1065          * for it, this is equivalent to the device signaling wakeup, so the
1066          * system suspend operation should be aborted.
1067          */
1068         if (pm_runtime_barrier(dev) && device_may_wakeup(dev))
1069                 pm_wakeup_event(dev, 0);
1070
1071         if (pm_wakeup_pending()) {
1072                 async_error = -EBUSY;
1073                 goto Complete;
1074         }
1075
1076         if (dev->power.syscore)
1077                 goto Complete;
1078
1079         device_lock(dev);
1080
1081         if (dev->pm_domain) {
1082                 info = "power domain ";
1083                 callback = pm_op(&dev->pm_domain->ops, state);
1084                 goto Run;
1085         }
1086
1087         if (dev->type && dev->type->pm) {
1088                 info = "type ";
1089                 callback = pm_op(dev->type->pm, state);
1090                 goto Run;
1091         }
1092
1093         if (dev->class) {
1094                 if (dev->class->pm) {
1095                         info = "class ";
1096                         callback = pm_op(dev->class->pm, state);
1097                         goto Run;
1098                 } else if (dev->class->suspend) {
1099                         pm_dev_dbg(dev, state, "legacy class ");
1100                         error = legacy_suspend(dev, state, dev->class->suspend);
1101                         goto End;
1102                 }
1103         }
1104
1105         if (dev->bus) {
1106                 if (dev->bus->pm) {
1107                         info = "bus ";
1108                         callback = pm_op(dev->bus->pm, state);
1109                 } else if (dev->bus->suspend) {
1110                         pm_dev_dbg(dev, state, "legacy bus ");
1111                         error = legacy_suspend(dev, state, dev->bus->suspend);
1112                         goto End;
1113                 }
1114         }
1115
1116  Run:
1117         if (!callback && dev->driver && dev->driver->pm) {
1118                 info = "driver ";
1119                 callback = pm_op(dev->driver->pm, state);
1120         }
1121
1122         error = dpm_run_callback(callback, dev, state, info);
1123
1124  End:
1125         if (!error) {
1126                 dev->power.is_suspended = true;
1127                 if (dev->power.wakeup_path
1128                     && dev->parent && !dev->parent->power.ignore_children)
1129                         dev->parent->power.wakeup_path = true;
1130         }
1131
1132         device_unlock(dev);
1133
1134  Complete:
1135         complete_all(&dev->power.completion);
1136
1137         if (error)
1138                 async_error = error;
1139         else if (dev->power.is_suspended)
1140                 __pm_runtime_disable(dev, false);
1141
1142         return error;
1143 }
1144
1145 static void async_suspend(void *data, async_cookie_t cookie)
1146 {
1147         struct device *dev = (struct device *)data;
1148         int error;
1149
1150         error = __device_suspend(dev, pm_transition, true);
1151         if (error) {
1152                 dpm_save_failed_dev(dev_name(dev));
1153                 pm_dev_err(dev, pm_transition, " async", error);
1154         }
1155
1156         put_device(dev);
1157 }
1158
1159 static int device_suspend(struct device *dev)
1160 {
1161         INIT_COMPLETION(dev->power.completion);
1162
1163         if (pm_async_enabled && dev->power.async_suspend) {
1164                 get_device(dev);
1165                 async_schedule(async_suspend, dev);
1166                 return 0;
1167         }
1168
1169         return __device_suspend(dev, pm_transition, false);
1170 }
1171
1172 /**
1173  * dpm_suspend - Execute "suspend" callbacks for all non-sysdev devices.
1174  * @state: PM transition of the system being carried out.
1175  */
1176 int dpm_suspend(pm_message_t state)
1177 {
1178         ktime_t starttime = ktime_get();
1179         int error = 0;
1180
1181         might_sleep();
1182
1183         mutex_lock(&dpm_list_mtx);
1184         pm_transition = state;
1185         async_error = 0;
1186         while (!list_empty(&dpm_prepared_list)) {
1187                 struct device *dev = to_device(dpm_prepared_list.prev);
1188
1189                 get_device(dev);
1190                 mutex_unlock(&dpm_list_mtx);
1191
1192                 error = device_suspend(dev);
1193
1194                 mutex_lock(&dpm_list_mtx);
1195                 if (error) {
1196                         pm_dev_err(dev, state, "", error);
1197                         dpm_save_failed_dev(dev_name(dev));
1198                         put_device(dev);
1199                         break;
1200                 }
1201                 if (!list_empty(&dev->power.entry))
1202                         list_move(&dev->power.entry, &dpm_suspended_list);
1203                 put_device(dev);
1204                 if (async_error)
1205                         break;
1206         }
1207         mutex_unlock(&dpm_list_mtx);
1208         async_synchronize_full();
1209         if (!error)
1210                 error = async_error;
1211         if (error) {
1212                 suspend_stats.failed_suspend++;
1213                 dpm_save_failed_step(SUSPEND_SUSPEND);
1214         } else
1215                 dpm_show_time(starttime, state, NULL);
1216         return error;
1217 }
1218
1219 /**
1220  * device_prepare - Prepare a device for system power transition.
1221  * @dev: Device to handle.
1222  * @state: PM transition of the system being carried out.
1223  *
1224  * Execute the ->prepare() callback(s) for given device.  No new children of the
1225  * device may be registered after this function has returned.
1226  */
1227 static int device_prepare(struct device *dev, pm_message_t state)
1228 {
1229         int (*callback)(struct device *) = NULL;
1230         char *info = NULL;
1231         int error = 0;
1232
1233         if (dev->power.syscore)
1234                 return 0;
1235
1236         /*
1237          * If a device's parent goes into runtime suspend at the wrong time,
1238          * it won't be possible to resume the device.  To prevent this we
1239          * block runtime suspend here, during the prepare phase, and allow
1240          * it again during the complete phase.
1241          */
1242         pm_runtime_get_noresume(dev);
1243
1244         device_lock(dev);
1245
1246         dev->power.wakeup_path = device_may_wakeup(dev);
1247
1248         if (dev->pm_domain) {
1249                 info = "preparing power domain ";
1250                 callback = dev->pm_domain->ops.prepare;
1251         } else if (dev->type && dev->type->pm) {
1252                 info = "preparing type ";
1253                 callback = dev->type->pm->prepare;
1254         } else if (dev->class && dev->class->pm) {
1255                 info = "preparing class ";
1256                 callback = dev->class->pm->prepare;
1257         } else if (dev->bus && dev->bus->pm) {
1258                 info = "preparing bus ";
1259                 callback = dev->bus->pm->prepare;
1260         }
1261
1262         if (!callback && dev->driver && dev->driver->pm) {
1263                 info = "preparing driver ";
1264                 callback = dev->driver->pm->prepare;
1265         }
1266
1267         if (callback) {
1268                 error = callback(dev);
1269                 suspend_report_result(callback, error);
1270         }
1271
1272         device_unlock(dev);
1273
1274         return error;
1275 }
1276
1277 /**
1278  * dpm_prepare - Prepare all non-sysdev devices for a system PM transition.
1279  * @state: PM transition of the system being carried out.
1280  *
1281  * Execute the ->prepare() callback(s) for all devices.
1282  */
1283 int dpm_prepare(pm_message_t state)
1284 {
1285         int error = 0;
1286
1287         might_sleep();
1288
1289         mutex_lock(&dpm_list_mtx);
1290         while (!list_empty(&dpm_list)) {
1291                 struct device *dev = to_device(dpm_list.next);
1292
1293                 get_device(dev);
1294                 mutex_unlock(&dpm_list_mtx);
1295
1296                 error = device_prepare(dev, state);
1297
1298                 mutex_lock(&dpm_list_mtx);
1299                 if (error) {
1300                         if (error == -EAGAIN) {
1301                                 put_device(dev);
1302                                 error = 0;
1303                                 continue;
1304                         }
1305                         printk(KERN_INFO "PM: Device %s not prepared "
1306                                 "for power transition: code %d\n",
1307                                 dev_name(dev), error);
1308                         put_device(dev);
1309                         break;
1310                 }
1311                 dev->power.is_prepared = true;
1312                 if (!list_empty(&dev->power.entry))
1313                         list_move_tail(&dev->power.entry, &dpm_prepared_list);
1314                 put_device(dev);
1315         }
1316         mutex_unlock(&dpm_list_mtx);
1317         return error;
1318 }
1319
1320 /**
1321  * dpm_suspend_start - Prepare devices for PM transition and suspend them.
1322  * @state: PM transition of the system being carried out.
1323  *
1324  * Prepare all non-sysdev devices for system PM transition and execute "suspend"
1325  * callbacks for them.
1326  */
1327 int dpm_suspend_start(pm_message_t state)
1328 {
1329         int error;
1330
1331         error = dpm_prepare(state);
1332         if (error) {
1333                 suspend_stats.failed_prepare++;
1334                 dpm_save_failed_step(SUSPEND_PREPARE);
1335         } else
1336                 error = dpm_suspend(state);
1337         return error;
1338 }
1339 EXPORT_SYMBOL_GPL(dpm_suspend_start);
1340
1341 void __suspend_report_result(const char *function, void *fn, int ret)
1342 {
1343         if (ret)
1344                 printk(KERN_ERR "%s(): %pF returns %d\n", function, fn, ret);
1345 }
1346 EXPORT_SYMBOL_GPL(__suspend_report_result);
1347
1348 /**
1349  * device_pm_wait_for_dev - Wait for suspend/resume of a device to complete.
1350  * @dev: Device to wait for.
1351  * @subordinate: Device that needs to wait for @dev.
1352  */
1353 int device_pm_wait_for_dev(struct device *subordinate, struct device *dev)
1354 {
1355         dpm_wait(dev, subordinate->power.async_suspend);
1356         return async_error;
1357 }
1358 EXPORT_SYMBOL_GPL(device_pm_wait_for_dev);
1359
1360 /**
1361  * dpm_for_each_dev - device iterator.
1362  * @data: data for the callback.
1363  * @fn: function to be called for each device.
1364  *
1365  * Iterate over devices in dpm_list, and call @fn for each device,
1366  * passing it @data.
1367  */
1368 void dpm_for_each_dev(void *data, void (*fn)(struct device *, void *))
1369 {
1370         struct device *dev;
1371
1372         if (!fn)
1373                 return;
1374
1375         device_pm_lock();
1376         list_for_each_entry(dev, &dpm_list, power.entry)
1377                 fn(dev, data);
1378         device_pm_unlock();
1379 }
1380 EXPORT_SYMBOL_GPL(dpm_for_each_dev);