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