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 intialize 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/mutex.h>
  23 #include <linux/pm.h>
  24 #include <linux/pm_runtime.h>
  25 #include <linux/resume-trace.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/sched.h>
  28 #include <linux/async.h>
  29
  30 #include "../base.h"
  31 #include "power.h"
  32
  33 /*
  34  * The entries in the dpm_list list are in a depth first order, simply
  35  * because children are guaranteed to be discovered after parents, and
  36  * are inserted at the back of the list on discovery.
  37  *
  38  * Since device_pm_add() may be called with a device lock held,
  39  * we must never try to acquire a device lock while holding
  40  * dpm_list_mutex.
  41  */
  42
  43 LIST_HEAD(dpm_list);
  44
  45 static DEFINE_MUTEX(dpm_list_mtx);
  46 static pm_message_t pm_transition;
  47
  48 /*
  49  * Set once the preparation of devices for a PM transition has started, reset
  50  * before starting to resume devices.  Protected by dpm_list_mtx.
  51  */
  52 static bool transition_started;
  53
  54 static int async_error;
  55
  56 /**
  57  * device_pm_init - Initialize the PM-related part of a device object.
  58  * @dev: Device object being initialized.
  59  */
  60 void device_pm_init(struct device *dev)
  61 {
  62         dev->power.status = DPM_ON;
  63         init_completion(&dev->power.completion);
  64         complete_all(&dev->power.completion);
  65         dev->power.wakeup = NULL;
  66         spin_lock_init(&dev->power.lock);
  67         pm_runtime_init(dev);
  68 }
  69
  70 /**
  71  * device_pm_lock - Lock the list of active devices used by the PM core.
  72  */
  73 void device_pm_lock(void)
  74 {
  75         mutex_lock(&dpm_list_mtx);
  76 }
  77
  78 /**
  79  * device_pm_unlock - Unlock the list of active devices used by the PM core.
  80  */
  81 void device_pm_unlock(void)
  82 {
  83         mutex_unlock(&dpm_list_mtx);
  84 }
  85
  86 /**
  87  * device_pm_add - Add a device to the PM core's list of active devices.
  88  * @dev: Device to add to the list.
  89  */
  90 void device_pm_add(struct device *dev)
  91 {
  92         pr_debug("PM: Adding info for %s:%s\n",
  93                  dev->bus ? dev->bus->name : "No Bus",
  94                  kobject_name(&dev->kobj));
  95         mutex_lock(&dpm_list_mtx);
  96         if (dev->parent) {
  97                 if (dev->parent->power.status >= DPM_SUSPENDING)
  98                         dev_warn(dev, "parent %s should not be sleeping\n",
  99                                  dev_name(dev->parent));
 100         } else if (transition_started) {
 101                 /*
 102                  * We refuse to register parentless devices while a PM
 103                  * transition is in progress in order to avoid leaving them
 104                  * unhandled down the road
 105                  */
 106                 dev_WARN(dev, "Parentless device registered during a PM transaction\n");
 107         }
 108
 109         list_add_tail(&dev->power.entry, &dpm_list);
 110         mutex_unlock(&dpm_list_mtx);
 111 }
 112
 113 /**
 114  * device_pm_remove - Remove a device from the PM core's list of active devices.
 115  * @dev: Device to be removed from the list.
 116  */
 117 void device_pm_remove(struct device *dev)
 118 {
 119         pr_debug("PM: Removing info for %s:%s\n",
 120                  dev->bus ? dev->bus->name : "No Bus",
 121                  kobject_name(&dev->kobj));
 122         complete_all(&dev->power.completion);
 123         mutex_lock(&dpm_list_mtx);
 124         list_del_init(&dev->power.entry);
 125         mutex_unlock(&dpm_list_mtx);
 126         device_wakeup_disable(dev);
 127         pm_runtime_remove(dev);
 128 }
 129
 130 /**
 131  * device_pm_move_before - Move device in the PM core's list of active devices.
 132  * @deva: Device to move in dpm_list.
 133  * @devb: Device @deva should come before.
 134  */
 135 void device_pm_move_before(struct device *deva, struct device *devb)
 136 {
 137         pr_debug("PM: Moving %s:%s before %s:%s\n",
 138                  deva->bus ? deva->bus->name : "No Bus",
 139                  kobject_name(&deva->kobj),
 140                  devb->bus ? devb->bus->name : "No Bus",
 141                  kobject_name(&devb->kobj));
 142         /* Delete deva from dpm_list and reinsert before devb. */
 143         list_move_tail(&deva->power.entry, &devb->power.entry);
 144 }
 145
 146 /**
 147  * device_pm_move_after - Move device in the PM core's list of active devices.
 148  * @deva: Device to move in dpm_list.
 149  * @devb: Device @deva should come after.
 150  */
 151 void device_pm_move_after(struct device *deva, struct device *devb)
 152 {
 153         pr_debug("PM: Moving %s:%s after %s:%s\n",
 154                  deva->bus ? deva->bus->name : "No Bus",
 155                  kobject_name(&deva->kobj),
 156                  devb->bus ? devb->bus->name : "No Bus",
 157                  kobject_name(&devb->kobj));
 158         /* Delete deva from dpm_list and reinsert after devb. */
 159         list_move(&deva->power.entry, &devb->power.entry);
 160 }
 161
 162 /**
 163  * device_pm_move_last - Move device to end of the PM core's list of devices.
 164  * @dev: Device to move in dpm_list.
 165  */
 166 void device_pm_move_last(struct device *dev)
 167 {
 168         pr_debug("PM: Moving %s:%s to end of list\n",
 169                  dev->bus ? dev->bus->name : "No Bus",
 170                  kobject_name(&dev->kobj));
 171         list_move_tail(&dev->power.entry, &dpm_list);
 172 }
 173
 174 static ktime_t initcall_debug_start(struct device *dev)
 175 {
 176         ktime_t calltime = ktime_set(0, 0);
 177
 178         if (initcall_debug) {
 179                 pr_info("calling  %s+ @ %i\n",
 180                                 dev_name(dev), task_pid_nr(current));
 181                 calltime = ktime_get();
 182         }
 183
 184         return calltime;
 185 }
 186
 187 static void initcall_debug_report(struct device *dev, ktime_t calltime,
 188                                   int error)
 189 {
 190         ktime_t delta, rettime;
 191
 192         if (initcall_debug) {
 193                 rettime = ktime_get();
 194                 delta = ktime_sub(rettime, calltime);
 195                 pr_info("call %s+ returned %d after %Ld usecs\n", dev_name(dev),
 196                         error, (unsigned long long)ktime_to_ns(delta) >> 10);
 197         }
 198 }
 199
 200 /**
 201  * dpm_wait - Wait for a PM operation to complete.
 202  * @dev: Device to wait for.
 203  * @async: If unset, wait only if the device's power.async_suspend flag is set.
 204  */
 205 static void dpm_wait(struct device *dev, bool async)
 206 {
 207         if (!dev)
 208                 return;
 209
 210         if (async || (pm_async_enabled && dev->power.async_suspend))
 211                 wait_for_completion(&dev->power.completion);
 212 }
 213
 214 static int dpm_wait_fn(struct device *dev, void *async_ptr)
 215 {
 216         dpm_wait(dev, *((bool *)async_ptr));
 217         return 0;
 218 }
 219
 220 static void dpm_wait_for_children(struct device *dev, bool async)
 221 {
 222        device_for_each_child(dev, &async, dpm_wait_fn);
 223 }
 224
 225 /**
 226  * pm_op - Execute the PM operation appropriate for given PM event.
 227  * @dev: Device to handle.
 228  * @ops: PM operations to choose from.
 229  * @state: PM transition of the system being carried out.
 230  */
 231 static int pm_op(struct device *dev,
 232                  const struct dev_pm_ops *ops,
 233                  pm_message_t state)
 234 {
 235         int error = 0;
 236         ktime_t calltime;
 237
 238         calltime = initcall_debug_start(dev);
 239
 240         switch (state.event) {
 241 #ifdef CONFIG_SUSPEND
 242         case PM_EVENT_SUSPEND:
 243                 if (ops->suspend) {
 244                         error = ops->suspend(dev);
 245                         suspend_report_result(ops->suspend, error);
 246                 }
 247                 break;
 248         case PM_EVENT_RESUME:
 249                 if (ops->resume) {
 250                         error = ops->resume(dev);
 251                         suspend_report_result(ops->resume, error);
 252                 }
 253                 break;
 254 #endif /* CONFIG_SUSPEND */
 255 #ifdef CONFIG_HIBERNATION
 256         case PM_EVENT_FREEZE:
 257         case PM_EVENT_QUIESCE:
 258                 if (ops->freeze) {
 259                         error = ops->freeze(dev);
 260                         suspend_report_result(ops->freeze, error);
 261                 }
 262                 break;
 263         case PM_EVENT_HIBERNATE:
 264                 if (ops->poweroff) {
 265                         error = ops->poweroff(dev);
 266                         suspend_report_result(ops->poweroff, error);
 267                 }
 268                 break;
 269         case PM_EVENT_THAW:
 270         case PM_EVENT_RECOVER:
 271                 if (ops->thaw) {
 272                         error = ops->thaw(dev);
 273                         suspend_report_result(ops->thaw, error);
 274                 }
 275                 break;
 276         case PM_EVENT_RESTORE:
 277                 if (ops->restore) {
 278                         error = ops->restore(dev);
 279                         suspend_report_result(ops->restore, error);
 280                 }
 281                 break;
 282 #endif /* CONFIG_HIBERNATION */
 283         default:
 284                 error = -EINVAL;
 285         }
 286
 287         initcall_debug_report(dev, calltime, error);
 288
 289         return error;
 290 }
 291
 292 /**
 293  * pm_noirq_op - Execute the PM operation appropriate for given PM event.
 294  * @dev: Device to handle.
 295  * @ops: PM operations to choose from.
 296  * @state: PM transition of the system being carried out.
 297  *
 298  * The driver of @dev will not receive interrupts while this function is being
 299  * executed.
 300  */
 301 static int pm_noirq_op(struct device *dev,
 302                         const struct dev_pm_ops *ops,
 303                         pm_message_t state)
 304 {
 305         int error = 0;
 306         ktime_t calltime, delta, rettime;
 307
 308         if (initcall_debug) {
 309                 pr_info("calling  %s+ @ %i, parent: %s\n",
 310                                 dev_name(dev), task_pid_nr(current),
 311                                 dev->parent ? dev_name(dev->parent) : "none");
 312                 calltime = ktime_get();
 313         }
 314
 315         switch (state.event) {
 316 #ifdef CONFIG_SUSPEND
 317         case PM_EVENT_SUSPEND:
 318                 if (ops->suspend_noirq) {
 319                         error = ops->suspend_noirq(dev);
 320                         suspend_report_result(ops->suspend_noirq, error);
 321                 }
 322                 break;
 323         case PM_EVENT_RESUME:
 324                 if (ops->resume_noirq) {
 325                         error = ops->resume_noirq(dev);
 326                         suspend_report_result(ops->resume_noirq, error);
 327                 }
 328                 break;
 329 #endif /* CONFIG_SUSPEND */
 330 #ifdef CONFIG_HIBERNATION
 331         case PM_EVENT_FREEZE:
 332         case PM_EVENT_QUIESCE:
 333                 if (ops->freeze_noirq) {
 334                         error = ops->freeze_noirq(dev);
 335                         suspend_report_result(ops->freeze_noirq, error);
 336                 }
 337                 break;
 338         case PM_EVENT_HIBERNATE:
 339                 if (ops->poweroff_noirq) {
 340                         error = ops->poweroff_noirq(dev);
 341                         suspend_report_result(ops->poweroff_noirq, error);
 342                 }
 343                 break;
 344         case PM_EVENT_THAW:
 345         case PM_EVENT_RECOVER:
 346                 if (ops->thaw_noirq) {
 347                         error = ops->thaw_noirq(dev);
 348                         suspend_report_result(ops->thaw_noirq, error);
 349                 }
 350                 break;
 351         case PM_EVENT_RESTORE:
 352                 if (ops->restore_noirq) {
 353                         error = ops->restore_noirq(dev);
 354                         suspend_report_result(ops->restore_noirq, error);
 355                 }
 356                 break;
 357 #endif /* CONFIG_HIBERNATION */
 358         default:
 359                 error = -EINVAL;
 360         }
 361
 362         if (initcall_debug) {
 363                 rettime = ktime_get();
 364                 delta = ktime_sub(rettime, calltime);
 365                 printk("initcall %s_i+ returned %d after %Ld usecs\n",
 366                         dev_name(dev), error,
 367                         (unsigned long long)ktime_to_ns(delta) >> 10);
 368         }
 369
 370         return error;
 371 }
 372
 373 static char *pm_verb(int event)
 374 {
 375         switch (event) {
 376         case PM_EVENT_SUSPEND:
 377                 return "suspend";
 378         case PM_EVENT_RESUME:
 379                 return "resume";
 380         case PM_EVENT_FREEZE:
 381                 return "freeze";
 382         case PM_EVENT_QUIESCE:
 383                 return "quiesce";
 384         case PM_EVENT_HIBERNATE:
 385                 return "hibernate";
 386         case PM_EVENT_THAW:
 387                 return "thaw";
 388         case PM_EVENT_RESTORE:
 389                 return "restore";
 390         case PM_EVENT_RECOVER:
 391                 return "recover";
 392         default:
 393                 return "(unknown PM event)";
 394         }
 395 }
 396
 397 static void pm_dev_dbg(struct device *dev, pm_message_t state, char *info)
 398 {
 399         dev_dbg(dev, "%s%s%s\n", info, pm_verb(state.event),
 400                 ((state.event & PM_EVENT_SLEEP) && device_may_wakeup(dev)) ?
 401                 ", may wakeup" : "");
 402 }
 403
 404 static void pm_dev_err(struct device *dev, pm_message_t state, char *info,
 405                         int error)
 406 {
 407         printk(KERN_ERR "PM: Device %s failed to %s%s: error %d\n",
 408                 kobject_name(&dev->kobj), pm_verb(state.event), info, error);
 409 }
 410
 411 static void dpm_show_time(ktime_t starttime, pm_message_t state, char *info)
 412 {
 413         ktime_t calltime;
 414         u64 usecs64;
 415         int usecs;
 416
 417         calltime = ktime_get();
 418         usecs64 = ktime_to_ns(ktime_sub(calltime, starttime));
 419         do_div(usecs64, NSEC_PER_USEC);
 420         usecs = usecs64;
 421         if (usecs == 0)
 422                 usecs = 1;
 423         pr_info("PM: %s%s%s of devices complete after %ld.%03ld msecs\n",
 424                 info ?: "", info ? " " : "", pm_verb(state.event),
 425                 usecs / USEC_PER_MSEC, usecs % USEC_PER_MSEC);
 426 }
 427
 428 /*------------------------- Resume routines -------------------------*/
 429
 430 /**
 431  * device_resume_noirq - Execute an "early resume" callback for given device.
 432  * @dev: Device to handle.
 433  * @state: PM transition of the system being carried out.
 434  *
 435  * The driver of @dev will not receive interrupts while this function is being
 436  * executed.
 437  */
 438 static int device_resume_noirq(struct device *dev, pm_message_t state)
 439 {
 440         int error = 0;
 441
 442         TRACE_DEVICE(dev);
 443         TRACE_RESUME(0);
 444
 445         if (dev->bus && dev->bus->pm) {
 446                 pm_dev_dbg(dev, state, "EARLY ");
 447                 error = pm_noirq_op(dev, dev->bus->pm, state);
 448                 if (error)
 449                         goto End;
 450         }
 451
 452         if (dev->type && dev->type->pm) {
 453                 pm_dev_dbg(dev, state, "EARLY type ");
 454                 error = pm_noirq_op(dev, dev->type->pm, state);
 455                 if (error)
 456                         goto End;
 457         }
 458
 459         if (dev->class && dev->class->pm) {
 460                 pm_dev_dbg(dev, state, "EARLY class ");
 461                 error = pm_noirq_op(dev, dev->class->pm, state);
 462         }
 463
 464 End:
 465         TRACE_RESUME(error);
 466         return error;
 467 }
 468
 469 /**
 470  * dpm_resume_noirq - Execute "early resume" callbacks for non-sysdev devices.
 471  * @state: PM transition of the system being carried out.
 472  *
 473  * Call the "noirq" resume handlers for all devices marked as DPM_OFF_IRQ and
 474  * enable device drivers to receive interrupts.
 475  */
 476 void dpm_resume_noirq(pm_message_t state)
 477 {
 478         struct list_head list;
 479         ktime_t starttime = ktime_get();
 480
 481         INIT_LIST_HEAD(&list);
 482         mutex_lock(&dpm_list_mtx);
 483         transition_started = false;
 484         while (!list_empty(&dpm_list)) {
 485                 struct device *dev = to_device(dpm_list.next);
 486
 487                 get_device(dev);
 488                 if (dev->power.status > DPM_OFF) {
 489                         int error;
 490
 491                         dev->power.status = DPM_OFF;
 492                         mutex_unlock(&dpm_list_mtx);
 493
 494                         error = device_resume_noirq(dev, state);
 495
 496                         mutex_lock(&dpm_list_mtx);
 497                         if (error)
 498                                 pm_dev_err(dev, state, " early", error);
 499                 }
 500                 if (!list_empty(&dev->power.entry))
 501                         list_move_tail(&dev->power.entry, &list);
 502                 put_device(dev);
 503         }
 504         list_splice(&list, &dpm_list);
 505         mutex_unlock(&dpm_list_mtx);
 506         dpm_show_time(starttime, state, "early");
 507         resume_device_irqs();
 508 }
 509 EXPORT_SYMBOL_GPL(dpm_resume_noirq);
 510
 511 /**
 512  * legacy_resume - Execute a legacy (bus or class) resume callback for device.
 513  * @dev: Device to resume.
 514  * @cb: Resume callback to execute.
 515  */
 516 static int legacy_resume(struct device *dev, int (*cb)(struct device *dev))
 517 {
 518         int error;
 519         ktime_t calltime;
 520
 521         calltime = initcall_debug_start(dev);
 522
 523         error = cb(dev);
 524         suspend_report_result(cb, error);
 525
 526         initcall_debug_report(dev, calltime, error);
 527
 528         return error;
 529 }
 530
 531 /**
 532  * device_resume - Execute "resume" callbacks for given device.
 533  * @dev: Device to handle.
 534  * @state: PM transition of the system being carried out.
 535  * @async: If true, the device is being resumed asynchronously.
 536  */
 537 static int device_resume(struct device *dev, pm_message_t state, bool async)
 538 {
 539         int error = 0;
 540
 541         TRACE_DEVICE(dev);
 542         TRACE_RESUME(0);
 543
 544         dpm_wait(dev->parent, async);
 545         device_lock(dev);
 546
 547         dev->power.status = DPM_RESUMING;
 548
 549         if (dev->bus) {
 550                 if (dev->bus->pm) {
 551                         pm_dev_dbg(dev, state, "");
 552                         error = pm_op(dev, dev->bus->pm, state);
 553                 } else if (dev->bus->resume) {
 554                         pm_dev_dbg(dev, state, "legacy ");
 555                         error = legacy_resume(dev, dev->bus->resume);
 556                 }
 557                 if (error)
 558                         goto End;
 559         }
 560
 561         if (dev->type) {
 562                 if (dev->type->pm) {
 563                         pm_dev_dbg(dev, state, "type ");
 564                         error = pm_op(dev, dev->type->pm, state);
 565                 }
 566                 if (error)
 567                         goto End;
 568         }
 569
 570         if (dev->class) {
 571                 if (dev->class->pm) {
 572                         pm_dev_dbg(dev, state, "class ");
 573                         error = pm_op(dev, dev->class->pm, state);
 574                 } else if (dev->class->resume) {
 575                         pm_dev_dbg(dev, state, "legacy class ");
 576                         error = legacy_resume(dev, dev->class->resume);
 577                 }
 578         }
 579  End:
 580         device_unlock(dev);
 581         complete_all(&dev->power.completion);
 582
 583         TRACE_RESUME(error);
 584         return error;
 585 }
 586
 587 static void async_resume(void *data, async_cookie_t cookie)
 588 {
 589         struct device *dev = (struct device *)data;
 590         int error;
 591
 592         error = device_resume(dev, pm_transition, true);
 593         if (error)
 594                 pm_dev_err(dev, pm_transition, " async", error);
 595         put_device(dev);
 596 }
 597
 598 static bool is_async(struct device *dev)
 599 {
 600         return dev->power.async_suspend && pm_async_enabled
 601                 && !pm_trace_is_enabled();
 602 }
 603
 604 /**
 605  * dpm_resume - Execute "resume" callbacks for non-sysdev devices.
 606  * @state: PM transition of the system being carried out.
 607  *
 608  * Execute the appropriate "resume" callback for all devices whose status
 609  * indicates that they are suspended.
 610  */
 611 static void dpm_resume(pm_message_t state)
 612 {
 613         struct list_head list;
 614         struct device *dev;
 615         ktime_t starttime = ktime_get();
 616
 617         INIT_LIST_HEAD(&list);
 618         mutex_lock(&dpm_list_mtx);
 619         pm_transition = state;
 620         async_error = 0;
 621
 622         list_for_each_entry(dev, &dpm_list, power.entry) {
 623                 if (dev->power.status < DPM_OFF)
 624                         continue;
 625
 626                 INIT_COMPLETION(dev->power.completion);
 627                 if (is_async(dev)) {
 628                         get_device(dev);
 629                         async_schedule(async_resume, dev);
 630                 }
 631         }
 632
 633         while (!list_empty(&dpm_list)) {
 634                 dev = to_device(dpm_list.next);
 635                 get_device(dev);
 636                 if (dev->power.status >= DPM_OFF && !is_async(dev)) {
 637                         int error;
 638
 639                         mutex_unlock(&dpm_list_mtx);
 640
 641                         error = device_resume(dev, state, false);
 642
 643                         mutex_lock(&dpm_list_mtx);
 644                         if (error)
 645                                 pm_dev_err(dev, state, "", error);
 646                 } else if (dev->power.status == DPM_SUSPENDING) {
 647                         /* Allow new children of the device to be registered */
 648                         dev->power.status = DPM_RESUMING;
 649                 }
 650                 if (!list_empty(&dev->power.entry))
 651                         list_move_tail(&dev->power.entry, &list);
 652                 put_device(dev);
 653         }
 654         list_splice(&list, &dpm_list);
 655         mutex_unlock(&dpm_list_mtx);
 656         async_synchronize_full();
 657         dpm_show_time(starttime, state, NULL);
 658 }
 659
 660 /**
 661  * device_complete - Complete a PM transition for given device.
 662  * @dev: Device to handle.
 663  * @state: PM transition of the system being carried out.
 664  */
 665 static void device_complete(struct device *dev, pm_message_t state)
 666 {
 667         device_lock(dev);
 668
 669         if (dev->class && dev->class->pm && dev->class->pm->complete) {
 670                 pm_dev_dbg(dev, state, "completing class ");
 671                 dev->class->pm->complete(dev);
 672         }
 673
 674         if (dev->type && dev->type->pm && dev->type->pm->complete) {
 675                 pm_dev_dbg(dev, state, "completing type ");
 676                 dev->type->pm->complete(dev);
 677         }
 678
 679         if (dev->bus && dev->bus->pm && dev->bus->pm->complete) {
 680                 pm_dev_dbg(dev, state, "completing ");
 681                 dev->bus->pm->complete(dev);
 682         }
 683
 684         device_unlock(dev);
 685 }
 686
 687 /**
 688  * dpm_complete - Complete a PM transition for all non-sysdev devices.
 689  * @state: PM transition of the system being carried out.
 690  *
 691  * Execute the ->complete() callbacks for all devices whose PM status is not
 692  * DPM_ON (this allows new devices to be registered).
 693  */
 694 static void dpm_complete(pm_message_t state)
 695 {
 696         struct list_head list;
 697
 698         INIT_LIST_HEAD(&list);
 699         mutex_lock(&dpm_list_mtx);
 700         transition_started = false;
 701         while (!list_empty(&dpm_list)) {
 702                 struct device *dev = to_device(dpm_list.prev);
 703
 704                 get_device(dev);
 705                 if (dev->power.status > DPM_ON) {
 706                         dev->power.status = DPM_ON;
 707                         mutex_unlock(&dpm_list_mtx);
 708
 709                         device_complete(dev, state);
 710                         pm_runtime_put_sync(dev);
 711
 712                         mutex_lock(&dpm_list_mtx);
 713                 }
 714                 if (!list_empty(&dev->power.entry))
 715                         list_move(&dev->power.entry, &list);
 716                 put_device(dev);
 717         }
 718         list_splice(&list, &dpm_list);
 719         mutex_unlock(&dpm_list_mtx);
 720 }
 721
 722 /**
 723  * dpm_resume_end - Execute "resume" callbacks and complete system transition.
 724  * @state: PM transition of the system being carried out.
 725  *
 726  * Execute "resume" callbacks for all devices and complete the PM transition of
 727  * the system.
 728  */
 729 void dpm_resume_end(pm_message_t state)
 730 {
 731         might_sleep();
 732         dpm_resume(state);
 733         dpm_complete(state);
 734 }
 735 EXPORT_SYMBOL_GPL(dpm_resume_end);
 736
 737
 738 /*------------------------- Suspend routines -------------------------*/
 739
 740 /**
 741  * resume_event - Return a "resume" message for given "suspend" sleep state.
 742  * @sleep_state: PM message representing a sleep state.
 743  *
 744  * Return a PM message representing the resume event corresponding to given
 745  * sleep state.
 746  */
 747 static pm_message_t resume_event(pm_message_t sleep_state)
 748 {
 749         switch (sleep_state.event) {
 750         case PM_EVENT_SUSPEND:
 751                 return PMSG_RESUME;
 752         case PM_EVENT_FREEZE:
 753         case PM_EVENT_QUIESCE:
 754                 return PMSG_RECOVER;
 755         case PM_EVENT_HIBERNATE:
 756                 return PMSG_RESTORE;
 757         }
 758         return PMSG_ON;
 759 }
 760
 761 /**
 762  * device_suspend_noirq - Execute a "late suspend" callback for given device.
 763  * @dev: Device to handle.
 764  * @state: PM transition of the system being carried out.
 765  *
 766  * The driver of @dev will not receive interrupts while this function is being
 767  * executed.
 768  */
 769 static int device_suspend_noirq(struct device *dev, pm_message_t state)
 770 {
 771         int error = 0;
 772
 773         if (dev->class && dev->class->pm) {
 774                 pm_dev_dbg(dev, state, "LATE class ");
 775                 error = pm_noirq_op(dev, dev->class->pm, state);
 776                 if (error)
 777                         goto End;
 778         }
 779
 780         if (dev->type && dev->type->pm) {
 781                 pm_dev_dbg(dev, state, "LATE type ");
 782                 error = pm_noirq_op(dev, dev->type->pm, state);
 783                 if (error)
 784                         goto End;
 785         }
 786
 787         if (dev->bus && dev->bus->pm) {
 788                 pm_dev_dbg(dev, state, "LATE ");
 789                 error = pm_noirq_op(dev, dev->bus->pm, state);
 790         }
 791
 792 End:
 793         return error;
 794 }
 795
 796 /**
 797  * dpm_suspend_noirq - Execute "late suspend" callbacks for non-sysdev devices.
 798  * @state: PM transition of the system being carried out.
 799  *
 800  * Prevent device drivers from receiving interrupts and call the "noirq" suspend
 801  * handlers for all non-sysdev devices.
 802  */
 803 int dpm_suspend_noirq(pm_message_t state)
 804 {
 805         struct list_head list;
 806         ktime_t starttime = ktime_get();
 807         int error = 0;
 808
 809         INIT_LIST_HEAD(&list);
 810         suspend_device_irqs();
 811         mutex_lock(&dpm_list_mtx);
 812         while (!list_empty(&dpm_list)) {
 813                 struct device *dev = to_device(dpm_list.prev);
 814
 815                 get_device(dev);
 816                 mutex_unlock(&dpm_list_mtx);
 817
 818                 error = device_suspend_noirq(dev, state);
 819
 820                 mutex_lock(&dpm_list_mtx);
 821                 if (error) {
 822                         pm_dev_err(dev, state, " late", error);
 823                         put_device(dev);
 824                         break;
 825                 }
 826                 dev->power.status = DPM_OFF_IRQ;
 827                 if (!list_empty(&dev->power.entry))
 828                         list_move(&dev->power.entry, &list);
 829                 put_device(dev);
 830         }
 831         list_splice_tail(&list, &dpm_list);
 832         mutex_unlock(&dpm_list_mtx);
 833         if (error)
 834                 dpm_resume_noirq(resume_event(state));
 835         else
 836                 dpm_show_time(starttime, state, "late");
 837         return error;
 838 }
 839 EXPORT_SYMBOL_GPL(dpm_suspend_noirq);
 840
 841 /**
 842  * legacy_suspend - Execute a legacy (bus or class) suspend callback for device.
 843  * @dev: Device to suspend.
 844  * @state: PM transition of the system being carried out.
 845  * @cb: Suspend callback to execute.
 846  */
 847 static int legacy_suspend(struct device *dev, pm_message_t state,
 848                           int (*cb)(struct device *dev, pm_message_t state))
 849 {
 850         int error;
 851         ktime_t calltime;
 852
 853         calltime = initcall_debug_start(dev);
 854
 855         error = cb(dev, state);
 856         suspend_report_result(cb, error);
 857
 858         initcall_debug_report(dev, calltime, error);
 859
 860         return error;
 861 }
 862
 863 /**
 864  * device_suspend - Execute "suspend" callbacks for given device.
 865  * @dev: Device to handle.
 866  * @state: PM transition of the system being carried out.
 867  * @async: If true, the device is being suspended asynchronously.
 868  */
 869 static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 870 {
 871         int error = 0;
 872
 873         dpm_wait_for_children(dev, async);
 874         device_lock(dev);
 875
 876         if (async_error)
 877                 goto End;
 878
 879         if (dev->class) {
 880                 if (dev->class->pm) {
 881                         pm_dev_dbg(dev, state, "class ");
 882                         error = pm_op(dev, dev->class->pm, state);
 883                 } else if (dev->class->suspend) {
 884                         pm_dev_dbg(dev, state, "legacy class ");
 885                         error = legacy_suspend(dev, state, dev->class->suspend);
 886                 }
 887                 if (error)
 888                         goto End;
 889         }
 890
 891         if (dev->type) {
 892                 if (dev->type->pm) {
 893                         pm_dev_dbg(dev, state, "type ");
 894                         error = pm_op(dev, dev->type->pm, state);
 895                 }
 896                 if (error)
 897                         goto End;
 898         }
 899
 900         if (dev->bus) {
 901                 if (dev->bus->pm) {
 902                         pm_dev_dbg(dev, state, "");
 903                         error = pm_op(dev, dev->bus->pm, state);
 904                 } else if (dev->bus->suspend) {
 905                         pm_dev_dbg(dev, state, "legacy ");
 906                         error = legacy_suspend(dev, state, dev->bus->suspend);
 907                 }
 908         }
 909
 910         if (!error)
 911                 dev->power.status = DPM_OFF;
 912
 913  End:
 914         device_unlock(dev);
 915         complete_all(&dev->power.completion);
 916
 917         if (error)
 918                 async_error = error;
 919
 920         return error;
 921 }
 922
 923 static void async_suspend(void *data, async_cookie_t cookie)
 924 {
 925         struct device *dev = (struct device *)data;
 926         int error;
 927
 928         error = __device_suspend(dev, pm_transition, true);
 929         if (error)
 930                 pm_dev_err(dev, pm_transition, " async", error);
 931
 932         put_device(dev);
 933 }
 934
 935 static int device_suspend(struct device *dev)
 936 {
 937         INIT_COMPLETION(dev->power.completion);
 938
 939         if (pm_async_enabled && dev->power.async_suspend) {
 940                 get_device(dev);
 941                 async_schedule(async_suspend, dev);
 942                 return 0;
 943         }
 944
 945         return __device_suspend(dev, pm_transition, false);
 946 }
 947
 948 /**
 949  * dpm_suspend - Execute "suspend" callbacks for all non-sysdev devices.
 950  * @state: PM transition of the system being carried out.
 951  */
 952 static int dpm_suspend(pm_message_t state)
 953 {
 954         struct list_head list;
 955         ktime_t starttime = ktime_get();
 956         int error = 0;
 957
 958         INIT_LIST_HEAD(&list);
 959         mutex_lock(&dpm_list_mtx);
 960         pm_transition = state;
 961         async_error = 0;
 962         while (!list_empty(&dpm_list)) {
 963                 struct device *dev = to_device(dpm_list.prev);
 964
 965                 get_device(dev);
 966                 mutex_unlock(&dpm_list_mtx);
 967
 968                 error = device_suspend(dev);
 969
 970                 mutex_lock(&dpm_list_mtx);
 971                 if (error) {
 972                         pm_dev_err(dev, state, "", error);
 973                         put_device(dev);
 974                         break;
 975                 }
 976                 if (!list_empty(&dev->power.entry))
 977                         list_move(&dev->power.entry, &list);
 978                 put_device(dev);
 979                 if (async_error)
 980                         break;
 981         }
 982         list_splice(&list, dpm_list.prev);
 983         mutex_unlock(&dpm_list_mtx);
 984         async_synchronize_full();
 985         if (!error)
 986                 error = async_error;
 987         if (!error)
 988                 dpm_show_time(starttime, state, NULL);
 989         return error;
 990 }
 991
 992 /**
 993  * device_prepare - Prepare a device for system power transition.
 994  * @dev: Device to handle.
 995  * @state: PM transition of the system being carried out.
 996  *
 997  * Execute the ->prepare() callback(s) for given device.  No new children of the
 998  * device may be registered after this function has returned.
 999  */
1000 static int device_prepare(struct device *dev, pm_message_t state)
1001 {
1002         int error = 0;
1003
1004         device_lock(dev);
1005
1006         if (dev->bus && dev->bus->pm && dev->bus->pm->prepare) {
1007                 pm_dev_dbg(dev, state, "preparing ");
1008                 error = dev->bus->pm->prepare(dev);
1009                 suspend_report_result(dev->bus->pm->prepare, error);
1010                 if (error)
1011                         goto End;
1012         }
1013
1014         if (dev->type && dev->type->pm && dev->type->pm->prepare) {
1015                 pm_dev_dbg(dev, state, "preparing type ");
1016                 error = dev->type->pm->prepare(dev);
1017                 suspend_report_result(dev->type->pm->prepare, error);
1018                 if (error)
1019                         goto End;
1020         }
1021
1022         if (dev->class && dev->class->pm && dev->class->pm->prepare) {
1023                 pm_dev_dbg(dev, state, "preparing class ");
1024                 error = dev->class->pm->prepare(dev);
1025                 suspend_report_result(dev->class->pm->prepare, error);
1026         }
1027  End:
1028         device_unlock(dev);
1029
1030         return error;
1031 }
1032
1033 /**
1034  * dpm_prepare - Prepare all non-sysdev devices for a system PM transition.
1035  * @state: PM transition of the system being carried out.
1036  *
1037  * Execute the ->prepare() callback(s) for all devices.
1038  */
1039 static int dpm_prepare(pm_message_t state)
1040 {
1041         struct list_head list;
1042         int error = 0;
1043
1044         INIT_LIST_HEAD(&list);
1045         mutex_lock(&dpm_list_mtx);
1046         transition_started = true;
1047         while (!list_empty(&dpm_list)) {
1048                 struct device *dev = to_device(dpm_list.next);
1049
1050                 get_device(dev);
1051                 dev->power.status = DPM_PREPARING;
1052                 mutex_unlock(&dpm_list_mtx);
1053
1054                 pm_runtime_get_noresume(dev);
1055                 if (pm_runtime_barrier(dev) && device_may_wakeup(dev)) {
1056                         /* Wake-up requested during system sleep transition. */
1057                         pm_runtime_put_sync(dev);
1058                         error = -EBUSY;
1059                 } else {
1060                         error = device_prepare(dev, state);
1061                 }
1062
1063                 mutex_lock(&dpm_list_mtx);
1064                 if (error) {
1065                         dev->power.status = DPM_ON;
1066                         if (error == -EAGAIN) {
1067                                 put_device(dev);
1068                                 error = 0;
1069                                 continue;
1070                         }
1071                         printk(KERN_ERR "PM: Failed to prepare device %s "
1072                                 "for power transition: error %d\n",
1073                                 kobject_name(&dev->kobj), error);
1074                         put_device(dev);
1075                         break;
1076                 }
1077                 dev->power.status = DPM_SUSPENDING;
1078                 if (!list_empty(&dev->power.entry))
1079                         list_move_tail(&dev->power.entry, &list);
1080                 put_device(dev);
1081         }
1082         list_splice(&list, &dpm_list);
1083         mutex_unlock(&dpm_list_mtx);
1084         return error;
1085 }
1086
1087 /**
1088  * dpm_suspend_start - Prepare devices for PM transition and suspend them.
1089  * @state: PM transition of the system being carried out.
1090  *
1091  * Prepare all non-sysdev devices for system PM transition and execute "suspend"
1092  * callbacks for them.
1093  */
1094 int dpm_suspend_start(pm_message_t state)
1095 {
1096         int error;
1097
1098         might_sleep();
1099         error = dpm_prepare(state);
1100         if (!error)
1101                 error = dpm_suspend(state);
1102         return error;
1103 }
1104 EXPORT_SYMBOL_GPL(dpm_suspend_start);
1105
1106 void __suspend_report_result(const char *function, void *fn, int ret)
1107 {
1108         if (ret)
1109                 printk(KERN_ERR "%s(): %pF returns %d\n", function, fn, ret);
1110 }
1111 EXPORT_SYMBOL_GPL(__suspend_report_result);
1112
1113 /**
1114  * device_pm_wait_for_dev - Wait for suspend/resume of a device to complete.
1115  * @dev: Device to wait for.
1116  * @subordinate: Device that needs to wait for @dev.
1117  */
1118 int device_pm_wait_for_dev(struct device *subordinate, struct device *dev)
1119 {
1120         dpm_wait(dev, subordinate->power.async_suspend);
1121         return async_error;
1122 }
1123 EXPORT_SYMBOL_GPL(device_pm_wait_for_dev);