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 semaphore held,
  39  * we must never try to acquire a device semaphore 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 /**
  55  * device_pm_init - Initialize the PM-related part of a device object.
  56  * @dev: Device object being initialized.
  57  */
  58 void device_pm_init(struct device *dev)
  59 {
  60         dev->power.status = DPM_ON;
  61         init_completion(&dev->power.completion);
  62         pm_runtime_init(dev);
  63 }
  64
  65 /**
  66  * device_pm_lock - Lock the list of active devices used by the PM core.
  67  */
  68 void device_pm_lock(void)
  69 {
  70         mutex_lock(&dpm_list_mtx);
  71 }
  72
  73 /**
  74  * device_pm_unlock - Unlock the list of active devices used by the PM core.
  75  */
  76 void device_pm_unlock(void)
  77 {
  78         mutex_unlock(&dpm_list_mtx);
  79 }
  80
  81 /**
  82  * device_pm_add - Add a device to the PM core's list of active devices.
  83  * @dev: Device to add to the list.
  84  */
  85 void device_pm_add(struct device *dev)
  86 {
  87         pr_debug("PM: Adding info for %s:%s\n",
  88                  dev->bus ? dev->bus->name : "No Bus",
  89                  kobject_name(&dev->kobj));
  90         mutex_lock(&dpm_list_mtx);
  91         if (dev->parent) {
  92                 if (dev->parent->power.status >= DPM_SUSPENDING)
  93                         dev_warn(dev, "parent %s should not be sleeping\n",
  94                                  dev_name(dev->parent));
  95         } else if (transition_started) {
  96                 /*
  97                  * We refuse to register parentless devices while a PM
  98                  * transition is in progress in order to avoid leaving them
  99                  * unhandled down the road
 100                  */
 101                 dev_WARN(dev, "Parentless device registered during a PM transaction\n");
 102         }
 103
 104         list_add_tail(&dev->power.entry, &dpm_list);
 105         mutex_unlock(&dpm_list_mtx);
 106 }
 107
 108 /**
 109  * device_pm_remove - Remove a device from the PM core's list of active devices.
 110  * @dev: Device to be removed from the list.
 111  */
 112 void device_pm_remove(struct device *dev)
 113 {
 114         pr_debug("PM: Removing info for %s:%s\n",
 115                  dev->bus ? dev->bus->name : "No Bus",
 116                  kobject_name(&dev->kobj));
 117         complete_all(&dev->power.completion);
 118         mutex_lock(&dpm_list_mtx);
 119         list_del_init(&dev->power.entry);
 120         mutex_unlock(&dpm_list_mtx);
 121         pm_runtime_remove(dev);
 122 }
 123
 124 /**
 125  * device_pm_move_before - Move device in the PM core's list of active devices.
 126  * @deva: Device to move in dpm_list.
 127  * @devb: Device @deva should come before.
 128  */
 129 void device_pm_move_before(struct device *deva, struct device *devb)
 130 {
 131         pr_debug("PM: Moving %s:%s before %s:%s\n",
 132                  deva->bus ? deva->bus->name : "No Bus",
 133                  kobject_name(&deva->kobj),
 134                  devb->bus ? devb->bus->name : "No Bus",
 135                  kobject_name(&devb->kobj));
 136         /* Delete deva from dpm_list and reinsert before devb. */
 137         list_move_tail(&deva->power.entry, &devb->power.entry);
 138 }
 139
 140 /**
 141  * device_pm_move_after - Move device in the PM core's list of active devices.
 142  * @deva: Device to move in dpm_list.
 143  * @devb: Device @deva should come after.
 144  */
 145 void device_pm_move_after(struct device *deva, struct device *devb)
 146 {
 147         pr_debug("PM: Moving %s:%s after %s:%s\n",
 148                  deva->bus ? deva->bus->name : "No Bus",
 149                  kobject_name(&deva->kobj),
 150                  devb->bus ? devb->bus->name : "No Bus",
 151                  kobject_name(&devb->kobj));
 152         /* Delete deva from dpm_list and reinsert after devb. */
 153         list_move(&deva->power.entry, &devb->power.entry);
 154 }
 155
 156 /**
 157  * device_pm_move_last - Move device to end of the PM core's list of devices.
 158  * @dev: Device to move in dpm_list.
 159  */
 160 void device_pm_move_last(struct device *dev)
 161 {
 162         pr_debug("PM: Moving %s:%s to end of list\n",
 163                  dev->bus ? dev->bus->name : "No Bus",
 164                  kobject_name(&dev->kobj));
 165         list_move_tail(&dev->power.entry, &dpm_list);
 166 }
 167
 168 static ktime_t initcall_debug_start(struct device *dev)
 169 {
 170         ktime_t calltime = ktime_set(0, 0);
 171
 172         if (initcall_debug) {
 173                 pr_info("calling  %s+ @ %i\n",
 174                                 dev_name(dev), task_pid_nr(current));
 175                 calltime = ktime_get();
 176         }
 177
 178         return calltime;
 179 }
 180
 181 static void initcall_debug_report(struct device *dev, ktime_t calltime,
 182                                   int error)
 183 {
 184         ktime_t delta, rettime;
 185
 186         if (initcall_debug) {
 187                 rettime = ktime_get();
 188                 delta = ktime_sub(rettime, calltime);
 189                 pr_info("call %s+ returned %d after %Ld usecs\n", dev_name(dev),
 190                         error, (unsigned long long)ktime_to_ns(delta) >> 10);
 191         }
 192 }
 193
 194 /**
 195  * dpm_wait - Wait for a PM operation to complete.
 196  * @dev: Device to wait for.
 197  * @async: If unset, wait only if the device's power.async_suspend flag is set.
 198  */
 199 static void dpm_wait(struct device *dev, bool async)
 200 {
 201         if (!dev)
 202                 return;
 203
 204         if (async || (pm_async_enabled && dev->power.async_suspend))
 205                 wait_for_completion(&dev->power.completion);
 206 }
 207
 208 static int dpm_wait_fn(struct device *dev, void *async_ptr)
 209 {
 210         dpm_wait(dev, *((bool *)async_ptr));
 211         return 0;
 212 }
 213
 214 static void dpm_wait_for_children(struct device *dev, bool async)
 215 {
 216        device_for_each_child(dev, &async, dpm_wait_fn);
 217 }
 218
 219 /**
 220  * pm_op - Execute the PM operation appropriate for given PM event.
 221  * @dev: Device to handle.
 222  * @ops: PM operations to choose from.
 223  * @state: PM transition of the system being carried out.
 224  */
 225 static int pm_op(struct device *dev,
 226                  const struct dev_pm_ops *ops,
 227                  pm_message_t state)
 228 {
 229         int error = 0;
 230         ktime_t calltime;
 231
 232         calltime = initcall_debug_start(dev);
 233
 234         switch (state.event) {
 235 #ifdef CONFIG_SUSPEND
 236         case PM_EVENT_SUSPEND:
 237                 if (ops->suspend) {
 238                         error = ops->suspend(dev);
 239                         suspend_report_result(ops->suspend, error);
 240                 }
 241                 break;
 242         case PM_EVENT_RESUME:
 243                 if (ops->resume) {
 244                         error = ops->resume(dev);
 245                         suspend_report_result(ops->resume, error);
 246                 }
 247                 break;
 248 #endif /* CONFIG_SUSPEND */
 249 #ifdef CONFIG_HIBERNATION
 250         case PM_EVENT_FREEZE:
 251         case PM_EVENT_QUIESCE:
 252                 if (ops->freeze) {
 253                         error = ops->freeze(dev);
 254                         suspend_report_result(ops->freeze, error);
 255                 }
 256                 break;
 257         case PM_EVENT_HIBERNATE:
 258                 if (ops->poweroff) {
 259                         error = ops->poweroff(dev);
 260                         suspend_report_result(ops->poweroff, error);
 261                 }
 262                 break;
 263         case PM_EVENT_THAW:
 264         case PM_EVENT_RECOVER:
 265                 if (ops->thaw) {
 266                         error = ops->thaw(dev);
 267                         suspend_report_result(ops->thaw, error);
 268                 }
 269                 break;
 270         case PM_EVENT_RESTORE:
 271                 if (ops->restore) {
 272                         error = ops->restore(dev);
 273                         suspend_report_result(ops->restore, error);
 274                 }
 275                 break;
 276 #endif /* CONFIG_HIBERNATION */
 277         default:
 278                 error = -EINVAL;
 279         }
 280
 281         initcall_debug_report(dev, calltime, error);
 282
 283         return error;
 284 }
 285
 286 /**
 287  * pm_noirq_op - Execute the PM operation appropriate for given PM event.
 288  * @dev: Device to handle.
 289  * @ops: PM operations to choose from.
 290  * @state: PM transition of the system being carried out.
 291  *
 292  * The driver of @dev will not receive interrupts while this function is being
 293  * executed.
 294  */
 295 static int pm_noirq_op(struct device *dev,
 296                         const struct dev_pm_ops *ops,
 297                         pm_message_t state)
 298 {
 299         int error = 0;
 300         ktime_t calltime, delta, rettime;
 301
 302         if (initcall_debug) {
 303                 pr_info("calling  %s+ @ %i, parent: %s\n",
 304                                 dev_name(dev), task_pid_nr(current),
 305                                 dev->parent ? dev_name(dev->parent) : "none");
 306                 calltime = ktime_get();
 307         }
 308
 309         switch (state.event) {
 310 #ifdef CONFIG_SUSPEND
 311         case PM_EVENT_SUSPEND:
 312                 if (ops->suspend_noirq) {
 313                         error = ops->suspend_noirq(dev);
 314                         suspend_report_result(ops->suspend_noirq, error);
 315                 }
 316                 break;
 317         case PM_EVENT_RESUME:
 318                 if (ops->resume_noirq) {
 319                         error = ops->resume_noirq(dev);
 320                         suspend_report_result(ops->resume_noirq, error);
 321                 }
 322                 break;
 323 #endif /* CONFIG_SUSPEND */
 324 #ifdef CONFIG_HIBERNATION
 325         case PM_EVENT_FREEZE:
 326         case PM_EVENT_QUIESCE:
 327                 if (ops->freeze_noirq) {
 328                         error = ops->freeze_noirq(dev);
 329                         suspend_report_result(ops->freeze_noirq, error);
 330                 }
 331                 break;
 332         case PM_EVENT_HIBERNATE:
 333                 if (ops->poweroff_noirq) {
 334                         error = ops->poweroff_noirq(dev);
 335                         suspend_report_result(ops->poweroff_noirq, error);
 336                 }
 337                 break;
 338         case PM_EVENT_THAW:
 339         case PM_EVENT_RECOVER:
 340                 if (ops->thaw_noirq) {
 341                         error = ops->thaw_noirq(dev);
 342                         suspend_report_result(ops->thaw_noirq, error);
 343                 }
 344                 break;
 345         case PM_EVENT_RESTORE:
 346                 if (ops->restore_noirq) {
 347                         error = ops->restore_noirq(dev);
 348                         suspend_report_result(ops->restore_noirq, error);
 349                 }
 350                 break;
 351 #endif /* CONFIG_HIBERNATION */
 352         default:
 353                 error = -EINVAL;
 354         }
 355
 356         if (initcall_debug) {
 357                 rettime = ktime_get();
 358                 delta = ktime_sub(rettime, calltime);
 359                 printk("initcall %s_i+ returned %d after %Ld usecs\n",
 360                         dev_name(dev), error,
 361                         (unsigned long long)ktime_to_ns(delta) >> 10);
 362         }
 363
 364         return error;
 365 }
 366
 367 static char *pm_verb(int event)
 368 {
 369         switch (event) {
 370         case PM_EVENT_SUSPEND:
 371                 return "suspend";
 372         case PM_EVENT_RESUME:
 373                 return "resume";
 374         case PM_EVENT_FREEZE:
 375                 return "freeze";
 376         case PM_EVENT_QUIESCE:
 377                 return "quiesce";
 378         case PM_EVENT_HIBERNATE:
 379                 return "hibernate";
 380         case PM_EVENT_THAW:
 381                 return "thaw";
 382         case PM_EVENT_RESTORE:
 383                 return "restore";
 384         case PM_EVENT_RECOVER:
 385                 return "recover";
 386         default:
 387                 return "(unknown PM event)";
 388         }
 389 }
 390
 391 static void pm_dev_dbg(struct device *dev, pm_message_t state, char *info)
 392 {
 393         dev_dbg(dev, "%s%s%s\n", info, pm_verb(state.event),
 394                 ((state.event & PM_EVENT_SLEEP) && device_may_wakeup(dev)) ?
 395                 ", may wakeup" : "");
 396 }
 397
 398 static void pm_dev_err(struct device *dev, pm_message_t state, char *info,
 399                         int error)
 400 {
 401         printk(KERN_ERR "PM: Device %s failed to %s%s: error %d\n",
 402                 kobject_name(&dev->kobj), pm_verb(state.event), info, error);
 403 }
 404
 405 static void dpm_show_time(ktime_t starttime, pm_message_t state, char *info)
 406 {
 407         ktime_t calltime;
 408         s64 usecs64;
 409         int usecs;
 410
 411         calltime = ktime_get();
 412         usecs64 = ktime_to_ns(ktime_sub(calltime, starttime));
 413         do_div(usecs64, NSEC_PER_USEC);
 414         usecs = usecs64;
 415         if (usecs == 0)
 416                 usecs = 1;
 417         pr_info("PM: %s%s%s of devices complete after %ld.%03ld msecs\n",
 418                 info ?: "", info ? " " : "", pm_verb(state.event),
 419                 usecs / USEC_PER_MSEC, usecs % USEC_PER_MSEC);
 420 }
 421
 422 /*------------------------- Resume routines -------------------------*/
 423
 424 /**
 425  * device_resume_noirq - Execute an "early resume" callback for given device.
 426  * @dev: Device to handle.
 427  * @state: PM transition of the system being carried out.
 428  *
 429  * The driver of @dev will not receive interrupts while this function is being
 430  * executed.
 431  */
 432 static int device_resume_noirq(struct device *dev, pm_message_t state)
 433 {
 434         int error = 0;
 435
 436         TRACE_DEVICE(dev);
 437         TRACE_RESUME(0);
 438
 439         if (dev->bus && dev->bus->pm) {
 440                 pm_dev_dbg(dev, state, "EARLY ");
 441                 error = pm_noirq_op(dev, dev->bus->pm, state);
 442         }
 443
 444         TRACE_RESUME(error);
 445         return error;
 446 }
 447
 448 /**
 449  * dpm_resume_noirq - Execute "early resume" callbacks for non-sysdev devices.
 450  * @state: PM transition of the system being carried out.
 451  *
 452  * Call the "noirq" resume handlers for all devices marked as DPM_OFF_IRQ and
 453  * enable device drivers to receive interrupts.
 454  */
 455 void dpm_resume_noirq(pm_message_t state)
 456 {
 457         struct device *dev;
 458         ktime_t starttime = ktime_get();
 459
 460         mutex_lock(&dpm_list_mtx);
 461         transition_started = false;
 462         list_for_each_entry(dev, &dpm_list, power.entry)
 463                 if (dev->power.status > DPM_OFF) {
 464                         int error;
 465
 466                         dev->power.status = DPM_OFF;
 467                         error = device_resume_noirq(dev, state);
 468                         if (error)
 469                                 pm_dev_err(dev, state, " early", error);
 470                 }
 471         mutex_unlock(&dpm_list_mtx);
 472         dpm_show_time(starttime, state, "early");
 473         resume_device_irqs();
 474 }
 475 EXPORT_SYMBOL_GPL(dpm_resume_noirq);
 476
 477 /**
 478  * legacy_resume - Execute a legacy (bus or class) resume callback for device.
 479  * @dev: Device to resume.
 480  * @cb: Resume callback to execute.
 481  */
 482 static int legacy_resume(struct device *dev, int (*cb)(struct device *dev))
 483 {
 484         int error;
 485         ktime_t calltime;
 486
 487         calltime = initcall_debug_start(dev);
 488
 489         error = cb(dev);
 490         suspend_report_result(cb, error);
 491
 492         initcall_debug_report(dev, calltime, error);
 493
 494         return error;
 495 }
 496
 497 /**
 498  * __device_resume - Execute "resume" callbacks for given device.
 499  * @dev: Device to handle.
 500  * @state: PM transition of the system being carried out.
 501  * @async: If true, the device is being resumed asynchronously.
 502  */
 503 static int __device_resume(struct device *dev, pm_message_t state, bool async)
 504 {
 505         int error = 0;
 506
 507         TRACE_DEVICE(dev);
 508         TRACE_RESUME(0);
 509
 510         dpm_wait(dev->parent, async);
 511         down(&dev->sem);
 512
 513         if (dev->bus) {
 514                 if (dev->bus->pm) {
 515                         pm_dev_dbg(dev, state, "");
 516                         error = pm_op(dev, dev->bus->pm, state);
 517                 } else if (dev->bus->resume) {
 518                         pm_dev_dbg(dev, state, "legacy ");
 519                         error = legacy_resume(dev, dev->bus->resume);
 520                 }
 521                 if (error)
 522                         goto End;
 523         }
 524
 525         if (dev->type) {
 526                 if (dev->type->pm) {
 527                         pm_dev_dbg(dev, state, "type ");
 528                         error = pm_op(dev, dev->type->pm, state);
 529                 }
 530                 if (error)
 531                         goto End;
 532         }
 533
 534         if (dev->class) {
 535                 if (dev->class->pm) {
 536                         pm_dev_dbg(dev, state, "class ");
 537                         error = pm_op(dev, dev->class->pm, state);
 538                 } else if (dev->class->resume) {
 539                         pm_dev_dbg(dev, state, "legacy class ");
 540                         error = legacy_resume(dev, dev->class->resume);
 541                 }
 542         }
 543  End:
 544         up(&dev->sem);
 545         complete_all(&dev->power.completion);
 546
 547         TRACE_RESUME(error);
 548         return error;
 549 }
 550
 551 static void async_resume(void *data, async_cookie_t cookie)
 552 {
 553         struct device *dev = (struct device *)data;
 554         int error;
 555
 556         error = __device_resume(dev, pm_transition, true);
 557         if (error)
 558                 pm_dev_err(dev, pm_transition, " async", error);
 559         put_device(dev);
 560 }
 561
 562 static int device_resume(struct device *dev)
 563 {
 564         INIT_COMPLETION(dev->power.completion);
 565
 566         if (pm_async_enabled && dev->power.async_suspend
 567             && !pm_trace_is_enabled()) {
 568                 get_device(dev);
 569                 async_schedule(async_resume, dev);
 570                 return 0;
 571         }
 572
 573         return __device_resume(dev, pm_transition, false);
 574 }
 575
 576 /**
 577  * dpm_resume - Execute "resume" callbacks for non-sysdev devices.
 578  * @state: PM transition of the system being carried out.
 579  *
 580  * Execute the appropriate "resume" callback for all devices whose status
 581  * indicates that they are suspended.
 582  */
 583 static void dpm_resume(pm_message_t state)
 584 {
 585         struct list_head list;
 586         ktime_t starttime = ktime_get();
 587
 588         INIT_LIST_HEAD(&list);
 589         mutex_lock(&dpm_list_mtx);
 590         pm_transition = state;
 591         while (!list_empty(&dpm_list)) {
 592                 struct device *dev = to_device(dpm_list.next);
 593
 594                 get_device(dev);
 595                 if (dev->power.status >= DPM_OFF) {
 596                         int error;
 597
 598                         dev->power.status = DPM_RESUMING;
 599                         mutex_unlock(&dpm_list_mtx);
 600
 601                         error = device_resume(dev);
 602
 603                         mutex_lock(&dpm_list_mtx);
 604                         if (error)
 605                                 pm_dev_err(dev, state, "", error);
 606                 } else if (dev->power.status == DPM_SUSPENDING) {
 607                         /* Allow new children of the device to be registered */
 608                         dev->power.status = DPM_RESUMING;
 609                 }
 610                 if (!list_empty(&dev->power.entry))
 611                         list_move_tail(&dev->power.entry, &list);
 612                 put_device(dev);
 613         }
 614         list_splice(&list, &dpm_list);
 615         mutex_unlock(&dpm_list_mtx);
 616         async_synchronize_full();
 617         dpm_show_time(starttime, state, NULL);
 618 }
 619
 620 /**
 621  * device_complete - Complete a PM transition for given device.
 622  * @dev: Device to handle.
 623  * @state: PM transition of the system being carried out.
 624  */
 625 static void device_complete(struct device *dev, pm_message_t state)
 626 {
 627         down(&dev->sem);
 628
 629         if (dev->class && dev->class->pm && dev->class->pm->complete) {
 630                 pm_dev_dbg(dev, state, "completing class ");
 631                 dev->class->pm->complete(dev);
 632         }
 633
 634         if (dev->type && dev->type->pm && dev->type->pm->complete) {
 635                 pm_dev_dbg(dev, state, "completing type ");
 636                 dev->type->pm->complete(dev);
 637         }
 638
 639         if (dev->bus && dev->bus->pm && dev->bus->pm->complete) {
 640                 pm_dev_dbg(dev, state, "completing ");
 641                 dev->bus->pm->complete(dev);
 642         }
 643
 644         up(&dev->sem);
 645 }
 646
 647 /**
 648  * dpm_complete - Complete a PM transition for all non-sysdev devices.
 649  * @state: PM transition of the system being carried out.
 650  *
 651  * Execute the ->complete() callbacks for all devices whose PM status is not
 652  * DPM_ON (this allows new devices to be registered).
 653  */
 654 static void dpm_complete(pm_message_t state)
 655 {
 656         struct list_head list;
 657
 658         INIT_LIST_HEAD(&list);
 659         mutex_lock(&dpm_list_mtx);
 660         transition_started = false;
 661         while (!list_empty(&dpm_list)) {
 662                 struct device *dev = to_device(dpm_list.prev);
 663
 664                 get_device(dev);
 665                 if (dev->power.status > DPM_ON) {
 666                         dev->power.status = DPM_ON;
 667                         mutex_unlock(&dpm_list_mtx);
 668
 669                         device_complete(dev, state);
 670                         pm_runtime_put_sync(dev);
 671
 672                         mutex_lock(&dpm_list_mtx);
 673                 }
 674                 if (!list_empty(&dev->power.entry))
 675                         list_move(&dev->power.entry, &list);
 676                 put_device(dev);
 677         }
 678         list_splice(&list, &dpm_list);
 679         mutex_unlock(&dpm_list_mtx);
 680 }
 681
 682 /**
 683  * dpm_resume_end - Execute "resume" callbacks and complete system transition.
 684  * @state: PM transition of the system being carried out.
 685  *
 686  * Execute "resume" callbacks for all devices and complete the PM transition of
 687  * the system.
 688  */
 689 void dpm_resume_end(pm_message_t state)
 690 {
 691         might_sleep();
 692         dpm_resume(state);
 693         dpm_complete(state);
 694 }
 695 EXPORT_SYMBOL_GPL(dpm_resume_end);
 696
 697
 698 /*------------------------- Suspend routines -------------------------*/
 699
 700 /**
 701  * resume_event - Return a "resume" message for given "suspend" sleep state.
 702  * @sleep_state: PM message representing a sleep state.
 703  *
 704  * Return a PM message representing the resume event corresponding to given
 705  * sleep state.
 706  */
 707 static pm_message_t resume_event(pm_message_t sleep_state)
 708 {
 709         switch (sleep_state.event) {
 710         case PM_EVENT_SUSPEND:
 711                 return PMSG_RESUME;
 712         case PM_EVENT_FREEZE:
 713         case PM_EVENT_QUIESCE:
 714                 return PMSG_RECOVER;
 715         case PM_EVENT_HIBERNATE:
 716                 return PMSG_RESTORE;
 717         }
 718         return PMSG_ON;
 719 }
 720
 721 /**
 722  * device_suspend_noirq - Execute a "late suspend" callback for given device.
 723  * @dev: Device to handle.
 724  * @state: PM transition of the system being carried out.
 725  *
 726  * The driver of @dev will not receive interrupts while this function is being
 727  * executed.
 728  */
 729 static int device_suspend_noirq(struct device *dev, pm_message_t state)
 730 {
 731         int error = 0;
 732
 733         if (dev->bus && dev->bus->pm) {
 734                 pm_dev_dbg(dev, state, "LATE ");
 735                 error = pm_noirq_op(dev, dev->bus->pm, state);
 736         }
 737         return error;
 738 }
 739
 740 /**
 741  * dpm_suspend_noirq - Execute "late suspend" callbacks for non-sysdev devices.
 742  * @state: PM transition of the system being carried out.
 743  *
 744  * Prevent device drivers from receiving interrupts and call the "noirq" suspend
 745  * handlers for all non-sysdev devices.
 746  */
 747 int dpm_suspend_noirq(pm_message_t state)
 748 {
 749         struct device *dev;
 750         ktime_t starttime = ktime_get();
 751         int error = 0;
 752
 753         suspend_device_irqs();
 754         mutex_lock(&dpm_list_mtx);
 755         list_for_each_entry_reverse(dev, &dpm_list, power.entry) {
 756                 error = device_suspend_noirq(dev, state);
 757                 if (error) {
 758                         pm_dev_err(dev, state, " late", error);
 759                         break;
 760                 }
 761                 dev->power.status = DPM_OFF_IRQ;
 762         }
 763         mutex_unlock(&dpm_list_mtx);
 764         if (error)
 765                 dpm_resume_noirq(resume_event(state));
 766         else
 767                 dpm_show_time(starttime, state, "late");
 768         return error;
 769 }
 770 EXPORT_SYMBOL_GPL(dpm_suspend_noirq);
 771
 772 /**
 773  * legacy_suspend - Execute a legacy (bus or class) suspend callback for device.
 774  * @dev: Device to suspend.
 775  * @state: PM transition of the system being carried out.
 776  * @cb: Suspend callback to execute.
 777  */
 778 static int legacy_suspend(struct device *dev, pm_message_t state,
 779                           int (*cb)(struct device *dev, pm_message_t state))
 780 {
 781         int error;
 782         ktime_t calltime;
 783
 784         calltime = initcall_debug_start(dev);
 785
 786         error = cb(dev, state);
 787         suspend_report_result(cb, error);
 788
 789         initcall_debug_report(dev, calltime, error);
 790
 791         return error;
 792 }
 793
 794 static int async_error;
 795
 796 /**
 797  * device_suspend - Execute "suspend" callbacks for given device.
 798  * @dev: Device to handle.
 799  * @state: PM transition of the system being carried out.
 800  * @async: If true, the device is being suspended asynchronously.
 801  */
 802 static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 803 {
 804         int error = 0;
 805
 806         dpm_wait_for_children(dev, async);
 807         down(&dev->sem);
 808
 809         if (async_error)
 810                 goto End;
 811
 812         if (dev->class) {
 813                 if (dev->class->pm) {
 814                         pm_dev_dbg(dev, state, "class ");
 815                         error = pm_op(dev, dev->class->pm, state);
 816                 } else if (dev->class->suspend) {
 817                         pm_dev_dbg(dev, state, "legacy class ");
 818                         error = legacy_suspend(dev, state, dev->class->suspend);
 819                 }
 820                 if (error)
 821                         goto End;
 822         }
 823
 824         if (dev->type) {
 825                 if (dev->type->pm) {
 826                         pm_dev_dbg(dev, state, "type ");
 827                         error = pm_op(dev, dev->type->pm, state);
 828                 }
 829                 if (error)
 830                         goto End;
 831         }
 832
 833         if (dev->bus) {
 834                 if (dev->bus->pm) {
 835                         pm_dev_dbg(dev, state, "");
 836                         error = pm_op(dev, dev->bus->pm, state);
 837                 } else if (dev->bus->suspend) {
 838                         pm_dev_dbg(dev, state, "legacy ");
 839                         error = legacy_suspend(dev, state, dev->bus->suspend);
 840                 }
 841         }
 842
 843         if (!error)
 844                 dev->power.status = DPM_OFF;
 845
 846  End:
 847         up(&dev->sem);
 848         complete_all(&dev->power.completion);
 849
 850         return error;
 851 }
 852
 853 static void async_suspend(void *data, async_cookie_t cookie)
 854 {
 855         struct device *dev = (struct device *)data;
 856         int error;
 857
 858         error = __device_suspend(dev, pm_transition, true);
 859         if (error) {
 860                 pm_dev_err(dev, pm_transition, " async", error);
 861                 async_error = error;
 862         }
 863
 864         put_device(dev);
 865 }
 866
 867 static int device_suspend(struct device *dev)
 868 {
 869         INIT_COMPLETION(dev->power.completion);
 870
 871         if (pm_async_enabled && dev->power.async_suspend) {
 872                 get_device(dev);
 873                 async_schedule(async_suspend, dev);
 874                 return 0;
 875         }
 876
 877         return __device_suspend(dev, pm_transition, false);
 878 }
 879
 880 /**
 881  * dpm_suspend - Execute "suspend" callbacks for all non-sysdev devices.
 882  * @state: PM transition of the system being carried out.
 883  */
 884 static int dpm_suspend(pm_message_t state)
 885 {
 886         struct list_head list;
 887         ktime_t starttime = ktime_get();
 888         int error = 0;
 889
 890         INIT_LIST_HEAD(&list);
 891         mutex_lock(&dpm_list_mtx);
 892         pm_transition = state;
 893         async_error = 0;
 894         while (!list_empty(&dpm_list)) {
 895                 struct device *dev = to_device(dpm_list.prev);
 896
 897                 get_device(dev);
 898                 mutex_unlock(&dpm_list_mtx);
 899
 900                 error = device_suspend(dev);
 901
 902                 mutex_lock(&dpm_list_mtx);
 903                 if (error) {
 904                         pm_dev_err(dev, state, "", error);
 905                         put_device(dev);
 906                         break;
 907                 }
 908                 if (!list_empty(&dev->power.entry))
 909                         list_move(&dev->power.entry, &list);
 910                 put_device(dev);
 911                 if (async_error)
 912                         break;
 913         }
 914         list_splice(&list, dpm_list.prev);
 915         mutex_unlock(&dpm_list_mtx);
 916         async_synchronize_full();
 917         if (!error)
 918                 error = async_error;
 919         if (!error)
 920                 dpm_show_time(starttime, state, NULL);
 921         return error;
 922 }
 923
 924 /**
 925  * device_prepare - Prepare a device for system power transition.
 926  * @dev: Device to handle.
 927  * @state: PM transition of the system being carried out.
 928  *
 929  * Execute the ->prepare() callback(s) for given device.  No new children of the
 930  * device may be registered after this function has returned.
 931  */
 932 static int device_prepare(struct device *dev, pm_message_t state)
 933 {
 934         int error = 0;
 935
 936         down(&dev->sem);
 937
 938         if (dev->bus && dev->bus->pm && dev->bus->pm->prepare) {
 939                 pm_dev_dbg(dev, state, "preparing ");
 940                 error = dev->bus->pm->prepare(dev);
 941                 suspend_report_result(dev->bus->pm->prepare, error);
 942                 if (error)
 943                         goto End;
 944         }
 945
 946         if (dev->type && dev->type->pm && dev->type->pm->prepare) {
 947                 pm_dev_dbg(dev, state, "preparing type ");
 948                 error = dev->type->pm->prepare(dev);
 949                 suspend_report_result(dev->type->pm->prepare, error);
 950                 if (error)
 951                         goto End;
 952         }
 953
 954         if (dev->class && dev->class->pm && dev->class->pm->prepare) {
 955                 pm_dev_dbg(dev, state, "preparing class ");
 956                 error = dev->class->pm->prepare(dev);
 957                 suspend_report_result(dev->class->pm->prepare, error);
 958         }
 959  End:
 960         up(&dev->sem);
 961
 962         return error;
 963 }
 964
 965 /**
 966  * dpm_prepare - Prepare all non-sysdev devices for a system PM transition.
 967  * @state: PM transition of the system being carried out.
 968  *
 969  * Execute the ->prepare() callback(s) for all devices.
 970  */
 971 static int dpm_prepare(pm_message_t state)
 972 {
 973         struct list_head list;
 974         int error = 0;
 975
 976         INIT_LIST_HEAD(&list);
 977         mutex_lock(&dpm_list_mtx);
 978         transition_started = true;
 979         while (!list_empty(&dpm_list)) {
 980                 struct device *dev = to_device(dpm_list.next);
 981
 982                 get_device(dev);
 983                 dev->power.status = DPM_PREPARING;
 984                 mutex_unlock(&dpm_list_mtx);
 985
 986                 pm_runtime_get_noresume(dev);
 987                 if (pm_runtime_barrier(dev) && device_may_wakeup(dev)) {
 988                         /* Wake-up requested during system sleep transition. */
 989                         pm_runtime_put_sync(dev);
 990                         error = -EBUSY;
 991                 } else {
 992                         error = device_prepare(dev, state);
 993                 }
 994
 995                 mutex_lock(&dpm_list_mtx);
 996                 if (error) {
 997                         dev->power.status = DPM_ON;
 998                         if (error == -EAGAIN) {
 999                                 put_device(dev);
1000                                 error = 0;
1001                                 continue;
1002                         }
1003                         printk(KERN_ERR "PM: Failed to prepare device %s "
1004                                 "for power transition: error %d\n",
1005                                 kobject_name(&dev->kobj), error);
1006                         put_device(dev);
1007                         break;
1008                 }
1009                 dev->power.status = DPM_SUSPENDING;
1010                 if (!list_empty(&dev->power.entry))
1011                         list_move_tail(&dev->power.entry, &list);
1012                 put_device(dev);
1013         }
1014         list_splice(&list, &dpm_list);
1015         mutex_unlock(&dpm_list_mtx);
1016         return error;
1017 }
1018
1019 /**
1020  * dpm_suspend_start - Prepare devices for PM transition and suspend them.
1021  * @state: PM transition of the system being carried out.
1022  *
1023  * Prepare all non-sysdev devices for system PM transition and execute "suspend"
1024  * callbacks for them.
1025  */
1026 int dpm_suspend_start(pm_message_t state)
1027 {
1028         int error;
1029
1030         might_sleep();
1031         error = dpm_prepare(state);
1032         if (!error)
1033                 error = dpm_suspend(state);
1034         return error;
1035 }
1036 EXPORT_SYMBOL_GPL(dpm_suspend_start);
1037
1038 void __suspend_report_result(const char *function, void *fn, int ret)
1039 {
1040         if (ret)
1041                 printk(KERN_ERR "%s(): %pF returns %d\n", function, fn, ret);
1042 }
1043 EXPORT_SYMBOL_GPL(__suspend_report_result);