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/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 device *dev;
 479         ktime_t starttime = ktime_get();
 480
 481         mutex_lock(&dpm_list_mtx);
 482         transition_started = false;
 483         list_for_each_entry(dev, &dpm_list, power.entry)
 484                 if (dev->power.status > DPM_OFF) {
 485                         int error;
 486
 487                         dev->power.status = DPM_OFF;
 488                         error = device_resume_noirq(dev, state);
 489                         if (error)
 490                                 pm_dev_err(dev, state, " early", error);
 491                 }
 492         mutex_unlock(&dpm_list_mtx);
 493         dpm_show_time(starttime, state, "early");
 494         resume_device_irqs();
 495 }
 496 EXPORT_SYMBOL_GPL(dpm_resume_noirq);
 497
 498 /**
 499  * legacy_resume - Execute a legacy (bus or class) resume callback for device.
 500  * @dev: Device to resume.
 501  * @cb: Resume callback to execute.
 502  */
 503 static int legacy_resume(struct device *dev, int (*cb)(struct device *dev))
 504 {
 505         int error;
 506         ktime_t calltime;
 507
 508         calltime = initcall_debug_start(dev);
 509
 510         error = cb(dev);
 511         suspend_report_result(cb, error);
 512
 513         initcall_debug_report(dev, calltime, error);
 514
 515         return error;
 516 }
 517
 518 /**
 519  * device_resume - Execute "resume" callbacks for given device.
 520  * @dev: Device to handle.
 521  * @state: PM transition of the system being carried out.
 522  * @async: If true, the device is being resumed asynchronously.
 523  */
 524 static int device_resume(struct device *dev, pm_message_t state, bool async)
 525 {
 526         int error = 0;
 527
 528         TRACE_DEVICE(dev);
 529         TRACE_RESUME(0);
 530
 531         dpm_wait(dev->parent, async);
 532         device_lock(dev);
 533
 534         dev->power.status = DPM_RESUMING;
 535
 536         if (dev->bus) {
 537                 if (dev->bus->pm) {
 538                         pm_dev_dbg(dev, state, "");
 539                         error = pm_op(dev, dev->bus->pm, state);
 540                 } else if (dev->bus->resume) {
 541                         pm_dev_dbg(dev, state, "legacy ");
 542                         error = legacy_resume(dev, dev->bus->resume);
 543                 }
 544                 if (error)
 545                         goto End;
 546         }
 547
 548         if (dev->type) {
 549                 if (dev->type->pm) {
 550                         pm_dev_dbg(dev, state, "type ");
 551                         error = pm_op(dev, dev->type->pm, state);
 552                 }
 553                 if (error)
 554                         goto End;
 555         }
 556
 557         if (dev->class) {
 558                 if (dev->class->pm) {
 559                         pm_dev_dbg(dev, state, "class ");
 560                         error = pm_op(dev, dev->class->pm, state);
 561                 } else if (dev->class->resume) {
 562                         pm_dev_dbg(dev, state, "legacy class ");
 563                         error = legacy_resume(dev, dev->class->resume);
 564                 }
 565         }
 566  End:
 567         device_unlock(dev);
 568         complete_all(&dev->power.completion);
 569
 570         TRACE_RESUME(error);
 571         return error;
 572 }
 573
 574 static void async_resume(void *data, async_cookie_t cookie)
 575 {
 576         struct device *dev = (struct device *)data;
 577         int error;
 578
 579         error = device_resume(dev, pm_transition, true);
 580         if (error)
 581                 pm_dev_err(dev, pm_transition, " async", error);
 582         put_device(dev);
 583 }
 584
 585 static bool is_async(struct device *dev)
 586 {
 587         return dev->power.async_suspend && pm_async_enabled
 588                 && !pm_trace_is_enabled();
 589 }
 590
 591 /**
 592  * dpm_resume - Execute "resume" callbacks for non-sysdev devices.
 593  * @state: PM transition of the system being carried out.
 594  *
 595  * Execute the appropriate "resume" callback for all devices whose status
 596  * indicates that they are suspended.
 597  */
 598 static void dpm_resume(pm_message_t state)
 599 {
 600         struct list_head list;
 601         struct device *dev;
 602         ktime_t starttime = ktime_get();
 603
 604         INIT_LIST_HEAD(&list);
 605         mutex_lock(&dpm_list_mtx);
 606         pm_transition = state;
 607         async_error = 0;
 608
 609         list_for_each_entry(dev, &dpm_list, power.entry) {
 610                 if (dev->power.status < DPM_OFF)
 611                         continue;
 612
 613                 INIT_COMPLETION(dev->power.completion);
 614                 if (is_async(dev)) {
 615                         get_device(dev);
 616                         async_schedule(async_resume, dev);
 617                 }
 618         }
 619
 620         while (!list_empty(&dpm_list)) {
 621                 dev = to_device(dpm_list.next);
 622                 get_device(dev);
 623                 if (dev->power.status >= DPM_OFF && !is_async(dev)) {
 624                         int error;
 625
 626                         mutex_unlock(&dpm_list_mtx);
 627
 628                         error = device_resume(dev, state, false);
 629
 630                         mutex_lock(&dpm_list_mtx);
 631                         if (error)
 632                                 pm_dev_err(dev, state, "", error);
 633                 } else if (dev->power.status == DPM_SUSPENDING) {
 634                         /* Allow new children of the device to be registered */
 635                         dev->power.status = DPM_RESUMING;
 636                 }
 637                 if (!list_empty(&dev->power.entry))
 638                         list_move_tail(&dev->power.entry, &list);
 639                 put_device(dev);
 640         }
 641         list_splice(&list, &dpm_list);
 642         mutex_unlock(&dpm_list_mtx);
 643         async_synchronize_full();
 644         dpm_show_time(starttime, state, NULL);
 645 }
 646
 647 /**
 648  * device_complete - Complete a PM transition for given device.
 649  * @dev: Device to handle.
 650  * @state: PM transition of the system being carried out.
 651  */
 652 static void device_complete(struct device *dev, pm_message_t state)
 653 {
 654         device_lock(dev);
 655
 656         if (dev->class && dev->class->pm && dev->class->pm->complete) {
 657                 pm_dev_dbg(dev, state, "completing class ");
 658                 dev->class->pm->complete(dev);
 659         }
 660
 661         if (dev->type && dev->type->pm && dev->type->pm->complete) {
 662                 pm_dev_dbg(dev, state, "completing type ");
 663                 dev->type->pm->complete(dev);
 664         }
 665
 666         if (dev->bus && dev->bus->pm && dev->bus->pm->complete) {
 667                 pm_dev_dbg(dev, state, "completing ");
 668                 dev->bus->pm->complete(dev);
 669         }
 670
 671         device_unlock(dev);
 672 }
 673
 674 /**
 675  * dpm_complete - Complete a PM transition for all non-sysdev devices.
 676  * @state: PM transition of the system being carried out.
 677  *
 678  * Execute the ->complete() callbacks for all devices whose PM status is not
 679  * DPM_ON (this allows new devices to be registered).
 680  */
 681 static void dpm_complete(pm_message_t state)
 682 {
 683         struct list_head list;
 684
 685         INIT_LIST_HEAD(&list);
 686         mutex_lock(&dpm_list_mtx);
 687         transition_started = false;
 688         while (!list_empty(&dpm_list)) {
 689                 struct device *dev = to_device(dpm_list.prev);
 690
 691                 get_device(dev);
 692                 if (dev->power.status > DPM_ON) {
 693                         dev->power.status = DPM_ON;
 694                         mutex_unlock(&dpm_list_mtx);
 695
 696                         device_complete(dev, state);
 697                         pm_runtime_put_sync(dev);
 698
 699                         mutex_lock(&dpm_list_mtx);
 700                 }
 701                 if (!list_empty(&dev->power.entry))
 702                         list_move(&dev->power.entry, &list);
 703                 put_device(dev);
 704         }
 705         list_splice(&list, &dpm_list);
 706         mutex_unlock(&dpm_list_mtx);
 707 }
 708
 709 /**
 710  * dpm_resume_end - Execute "resume" callbacks and complete system transition.
 711  * @state: PM transition of the system being carried out.
 712  *
 713  * Execute "resume" callbacks for all devices and complete the PM transition of
 714  * the system.
 715  */
 716 void dpm_resume_end(pm_message_t state)
 717 {
 718         might_sleep();
 719         dpm_resume(state);
 720         dpm_complete(state);
 721 }
 722 EXPORT_SYMBOL_GPL(dpm_resume_end);
 723
 724
 725 /*------------------------- Suspend routines -------------------------*/
 726
 727 /**
 728  * resume_event - Return a "resume" message for given "suspend" sleep state.
 729  * @sleep_state: PM message representing a sleep state.
 730  *
 731  * Return a PM message representing the resume event corresponding to given
 732  * sleep state.
 733  */
 734 static pm_message_t resume_event(pm_message_t sleep_state)
 735 {
 736         switch (sleep_state.event) {
 737         case PM_EVENT_SUSPEND:
 738                 return PMSG_RESUME;
 739         case PM_EVENT_FREEZE:
 740         case PM_EVENT_QUIESCE:
 741                 return PMSG_RECOVER;
 742         case PM_EVENT_HIBERNATE:
 743                 return PMSG_RESTORE;
 744         }
 745         return PMSG_ON;
 746 }
 747
 748 /**
 749  * device_suspend_noirq - Execute a "late suspend" callback for given device.
 750  * @dev: Device to handle.
 751  * @state: PM transition of the system being carried out.
 752  *
 753  * The driver of @dev will not receive interrupts while this function is being
 754  * executed.
 755  */
 756 static int device_suspend_noirq(struct device *dev, pm_message_t state)
 757 {
 758         int error = 0;
 759
 760         if (dev->class && dev->class->pm) {
 761                 pm_dev_dbg(dev, state, "LATE class ");
 762                 error = pm_noirq_op(dev, dev->class->pm, state);
 763                 if (error)
 764                         goto End;
 765         }
 766
 767         if (dev->type && dev->type->pm) {
 768                 pm_dev_dbg(dev, state, "LATE type ");
 769                 error = pm_noirq_op(dev, dev->type->pm, state);
 770                 if (error)
 771                         goto End;
 772         }
 773
 774         if (dev->bus && dev->bus->pm) {
 775                 pm_dev_dbg(dev, state, "LATE ");
 776                 error = pm_noirq_op(dev, dev->bus->pm, state);
 777         }
 778
 779 End:
 780         return error;
 781 }
 782
 783 /**
 784  * dpm_suspend_noirq - Execute "late suspend" callbacks for non-sysdev devices.
 785  * @state: PM transition of the system being carried out.
 786  *
 787  * Prevent device drivers from receiving interrupts and call the "noirq" suspend
 788  * handlers for all non-sysdev devices.
 789  */
 790 int dpm_suspend_noirq(pm_message_t state)
 791 {
 792         struct device *dev;
 793         ktime_t starttime = ktime_get();
 794         int error = 0;
 795
 796         suspend_device_irqs();
 797         mutex_lock(&dpm_list_mtx);
 798         list_for_each_entry_reverse(dev, &dpm_list, power.entry) {
 799                 error = device_suspend_noirq(dev, state);
 800                 if (error) {
 801                         pm_dev_err(dev, state, " late", error);
 802                         break;
 803                 }
 804                 dev->power.status = DPM_OFF_IRQ;
 805         }
 806         mutex_unlock(&dpm_list_mtx);
 807         if (error)
 808                 dpm_resume_noirq(resume_event(state));
 809         else
 810                 dpm_show_time(starttime, state, "late");
 811         return error;
 812 }
 813 EXPORT_SYMBOL_GPL(dpm_suspend_noirq);
 814
 815 /**
 816  * legacy_suspend - Execute a legacy (bus or class) suspend callback for device.
 817  * @dev: Device to suspend.
 818  * @state: PM transition of the system being carried out.
 819  * @cb: Suspend callback to execute.
 820  */
 821 static int legacy_suspend(struct device *dev, pm_message_t state,
 822                           int (*cb)(struct device *dev, pm_message_t state))
 823 {
 824         int error;
 825         ktime_t calltime;
 826
 827         calltime = initcall_debug_start(dev);
 828
 829         error = cb(dev, state);
 830         suspend_report_result(cb, error);
 831
 832         initcall_debug_report(dev, calltime, error);
 833
 834         return error;
 835 }
 836
 837 /**
 838  * device_suspend - Execute "suspend" callbacks for given device.
 839  * @dev: Device to handle.
 840  * @state: PM transition of the system being carried out.
 841  * @async: If true, the device is being suspended asynchronously.
 842  */
 843 static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 844 {
 845         int error = 0;
 846
 847         dpm_wait_for_children(dev, async);
 848         device_lock(dev);
 849
 850         if (async_error)
 851                 goto End;
 852
 853         if (dev->class) {
 854                 if (dev->class->pm) {
 855                         pm_dev_dbg(dev, state, "class ");
 856                         error = pm_op(dev, dev->class->pm, state);
 857                 } else if (dev->class->suspend) {
 858                         pm_dev_dbg(dev, state, "legacy class ");
 859                         error = legacy_suspend(dev, state, dev->class->suspend);
 860                 }
 861                 if (error)
 862                         goto End;
 863         }
 864
 865         if (dev->type) {
 866                 if (dev->type->pm) {
 867                         pm_dev_dbg(dev, state, "type ");
 868                         error = pm_op(dev, dev->type->pm, state);
 869                 }
 870                 if (error)
 871                         goto End;
 872         }
 873
 874         if (dev->bus) {
 875                 if (dev->bus->pm) {
 876                         pm_dev_dbg(dev, state, "");
 877                         error = pm_op(dev, dev->bus->pm, state);
 878                 } else if (dev->bus->suspend) {
 879                         pm_dev_dbg(dev, state, "legacy ");
 880                         error = legacy_suspend(dev, state, dev->bus->suspend);
 881                 }
 882         }
 883
 884         if (!error)
 885                 dev->power.status = DPM_OFF;
 886
 887  End:
 888         device_unlock(dev);
 889         complete_all(&dev->power.completion);
 890
 891         if (error)
 892                 async_error = error;
 893
 894         return error;
 895 }
 896
 897 static void async_suspend(void *data, async_cookie_t cookie)
 898 {
 899         struct device *dev = (struct device *)data;
 900         int error;
 901
 902         error = __device_suspend(dev, pm_transition, true);
 903         if (error)
 904                 pm_dev_err(dev, pm_transition, " async", error);
 905
 906         put_device(dev);
 907 }
 908
 909 static int device_suspend(struct device *dev)
 910 {
 911         INIT_COMPLETION(dev->power.completion);
 912
 913         if (pm_async_enabled && dev->power.async_suspend) {
 914                 get_device(dev);
 915                 async_schedule(async_suspend, dev);
 916                 return 0;
 917         }
 918
 919         return __device_suspend(dev, pm_transition, false);
 920 }
 921
 922 /**
 923  * dpm_suspend - Execute "suspend" callbacks for all non-sysdev devices.
 924  * @state: PM transition of the system being carried out.
 925  */
 926 static int dpm_suspend(pm_message_t state)
 927 {
 928         struct list_head list;
 929         ktime_t starttime = ktime_get();
 930         int error = 0;
 931
 932         INIT_LIST_HEAD(&list);
 933         mutex_lock(&dpm_list_mtx);
 934         pm_transition = state;
 935         async_error = 0;
 936         while (!list_empty(&dpm_list)) {
 937                 struct device *dev = to_device(dpm_list.prev);
 938
 939                 get_device(dev);
 940                 mutex_unlock(&dpm_list_mtx);
 941
 942                 error = device_suspend(dev);
 943
 944                 mutex_lock(&dpm_list_mtx);
 945                 if (error) {
 946                         pm_dev_err(dev, state, "", error);
 947                         put_device(dev);
 948                         break;
 949                 }
 950                 if (!list_empty(&dev->power.entry))
 951                         list_move(&dev->power.entry, &list);
 952                 put_device(dev);
 953                 if (async_error)
 954                         break;
 955         }
 956         list_splice(&list, dpm_list.prev);
 957         mutex_unlock(&dpm_list_mtx);
 958         async_synchronize_full();
 959         if (!error)
 960                 error = async_error;
 961         if (!error)
 962                 dpm_show_time(starttime, state, NULL);
 963         return error;
 964 }
 965
 966 /**
 967  * device_prepare - Prepare a device for system power transition.
 968  * @dev: Device to handle.
 969  * @state: PM transition of the system being carried out.
 970  *
 971  * Execute the ->prepare() callback(s) for given device.  No new children of the
 972  * device may be registered after this function has returned.
 973  */
 974 static int device_prepare(struct device *dev, pm_message_t state)
 975 {
 976         int error = 0;
 977
 978         device_lock(dev);
 979
 980         if (dev->bus && dev->bus->pm && dev->bus->pm->prepare) {
 981                 pm_dev_dbg(dev, state, "preparing ");
 982                 error = dev->bus->pm->prepare(dev);
 983                 suspend_report_result(dev->bus->pm->prepare, error);
 984                 if (error)
 985                         goto End;
 986         }
 987
 988         if (dev->type && dev->type->pm && dev->type->pm->prepare) {
 989                 pm_dev_dbg(dev, state, "preparing type ");
 990                 error = dev->type->pm->prepare(dev);
 991                 suspend_report_result(dev->type->pm->prepare, error);
 992                 if (error)
 993                         goto End;
 994         }
 995
 996         if (dev->class && dev->class->pm && dev->class->pm->prepare) {
 997                 pm_dev_dbg(dev, state, "preparing class ");
 998                 error = dev->class->pm->prepare(dev);
 999                 suspend_report_result(dev->class->pm->prepare, error);
1000         }
1001  End:
1002         device_unlock(dev);
1003
1004         return error;
1005 }
1006
1007 /**
1008  * dpm_prepare - Prepare all non-sysdev devices for a system PM transition.
1009  * @state: PM transition of the system being carried out.
1010  *
1011  * Execute the ->prepare() callback(s) for all devices.
1012  */
1013 static int dpm_prepare(pm_message_t state)
1014 {
1015         struct list_head list;
1016         int error = 0;
1017
1018         INIT_LIST_HEAD(&list);
1019         mutex_lock(&dpm_list_mtx);
1020         transition_started = true;
1021         while (!list_empty(&dpm_list)) {
1022                 struct device *dev = to_device(dpm_list.next);
1023
1024                 get_device(dev);
1025                 dev->power.status = DPM_PREPARING;
1026                 mutex_unlock(&dpm_list_mtx);
1027
1028                 pm_runtime_get_noresume(dev);
1029                 if (pm_runtime_barrier(dev) && device_may_wakeup(dev)) {
1030                         /* Wake-up requested during system sleep transition. */
1031                         pm_runtime_put_sync(dev);
1032                         error = -EBUSY;
1033                 } else {
1034                         error = device_prepare(dev, state);
1035                 }
1036
1037                 mutex_lock(&dpm_list_mtx);
1038                 if (error) {
1039                         dev->power.status = DPM_ON;
1040                         if (error == -EAGAIN) {
1041                                 put_device(dev);
1042                                 error = 0;
1043                                 continue;
1044                         }
1045                         printk(KERN_ERR "PM: Failed to prepare device %s "
1046                                 "for power transition: error %d\n",
1047                                 kobject_name(&dev->kobj), error);
1048                         put_device(dev);
1049                         break;
1050                 }
1051                 dev->power.status = DPM_SUSPENDING;
1052                 if (!list_empty(&dev->power.entry))
1053                         list_move_tail(&dev->power.entry, &list);
1054                 put_device(dev);
1055         }
1056         list_splice(&list, &dpm_list);
1057         mutex_unlock(&dpm_list_mtx);
1058         return error;
1059 }
1060
1061 /**
1062  * dpm_suspend_start - Prepare devices for PM transition and suspend them.
1063  * @state: PM transition of the system being carried out.
1064  *
1065  * Prepare all non-sysdev devices for system PM transition and execute "suspend"
1066  * callbacks for them.
1067  */
1068 int dpm_suspend_start(pm_message_t state)
1069 {
1070         int error;
1071
1072         might_sleep();
1073         error = dpm_prepare(state);
1074         if (!error)
1075                 error = dpm_suspend(state);
1076         return error;
1077 }
1078 EXPORT_SYMBOL_GPL(dpm_suspend_start);
1079
1080 void __suspend_report_result(const char *function, void *fn, int ret)
1081 {
1082         if (ret)
1083                 printk(KERN_ERR "%s(): %pF returns %d\n", function, fn, ret);
1084 }
1085 EXPORT_SYMBOL_GPL(__suspend_report_result);
1086
1087 /**
1088  * device_pm_wait_for_dev - Wait for suspend/resume of a device to complete.
1089  * @dev: Device to wait for.
1090  * @subordinate: Device that needs to wait for @dev.
1091  */
1092 int device_pm_wait_for_dev(struct device *subordinate, struct device *dev)
1093 {
1094         dpm_wait(dev, subordinate->power.async_suspend);
1095         return async_error;
1096 }
1097 EXPORT_SYMBOL_GPL(device_pm_wait_for_dev);