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   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/rwsem.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/sched.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
  47 /*
  48  * Set once the preparation of devices for a PM transition has started, reset
  49  * before starting to resume devices.  Protected by dpm_list_mtx.
  50  */
  51 static bool transition_started;
  52
  53 /**
  54  * device_pm_init - Initialize the PM-related part of a device object.
  55  * @dev: Device object being initialized.
  56  */
  57 void device_pm_init(struct device *dev)
  58 {
  59         dev->power.status = DPM_ON;
  60         pm_runtime_init(dev);
  61 }
  62
  63 /**
  64  * device_pm_lock - Lock the list of active devices used by the PM core.
  65  */
  66 void device_pm_lock(void)
  67 {
  68         mutex_lock(&dpm_list_mtx);
  69 }
  70
  71 /**
  72  * device_pm_unlock - Unlock the list of active devices used by the PM core.
  73  */
  74 void device_pm_unlock(void)
  75 {
  76         mutex_unlock(&dpm_list_mtx);
  77 }
  78
  79 /**
  80  * device_pm_add - Add a device to the PM core's list of active devices.
  81  * @dev: Device to add to the list.
  82  */
  83 void device_pm_add(struct device *dev)
  84 {
  85         pr_debug("PM: Adding info for %s:%s\n",
  86                  dev->bus ? dev->bus->name : "No Bus",
  87                  kobject_name(&dev->kobj));
  88         mutex_lock(&dpm_list_mtx);
  89         if (dev->parent) {
  90                 if (dev->parent->power.status >= DPM_SUSPENDING)
  91                         dev_warn(dev, "parent %s should not be sleeping\n",
  92                                  dev_name(dev->parent));
  93         } else if (transition_started) {
  94                 /*
  95                  * We refuse to register parentless devices while a PM
  96                  * transition is in progress in order to avoid leaving them
  97                  * unhandled down the road
  98                  */
  99                 dev_WARN(dev, "Parentless device registered during a PM transaction\n");
 100         }
 101
 102         list_add_tail(&dev->power.entry, &dpm_list);
 103         mutex_unlock(&dpm_list_mtx);
 104 }
 105
 106 /**
 107  * device_pm_remove - Remove a device from the PM core's list of active devices.
 108  * @dev: Device to be removed from the list.
 109  */
 110 void device_pm_remove(struct device *dev)
 111 {
 112         pr_debug("PM: Removing info for %s:%s\n",
 113                  dev->bus ? dev->bus->name : "No Bus",
 114                  kobject_name(&dev->kobj));
 115         mutex_lock(&dpm_list_mtx);
 116         list_del_init(&dev->power.entry);
 117         mutex_unlock(&dpm_list_mtx);
 118         pm_runtime_remove(dev);
 119 }
 120
 121 /**
 122  * device_pm_move_before - Move device in the PM core's list of active devices.
 123  * @deva: Device to move in dpm_list.
 124  * @devb: Device @deva should come before.
 125  */
 126 void device_pm_move_before(struct device *deva, struct device *devb)
 127 {
 128         pr_debug("PM: Moving %s:%s before %s:%s\n",
 129                  deva->bus ? deva->bus->name : "No Bus",
 130                  kobject_name(&deva->kobj),
 131                  devb->bus ? devb->bus->name : "No Bus",
 132                  kobject_name(&devb->kobj));
 133         /* Delete deva from dpm_list and reinsert before devb. */
 134         list_move_tail(&deva->power.entry, &devb->power.entry);
 135 }
 136
 137 /**
 138  * device_pm_move_after - Move device in the PM core's list of active devices.
 139  * @deva: Device to move in dpm_list.
 140  * @devb: Device @deva should come after.
 141  */
 142 void device_pm_move_after(struct device *deva, struct device *devb)
 143 {
 144         pr_debug("PM: Moving %s:%s after %s:%s\n",
 145                  deva->bus ? deva->bus->name : "No Bus",
 146                  kobject_name(&deva->kobj),
 147                  devb->bus ? devb->bus->name : "No Bus",
 148                  kobject_name(&devb->kobj));
 149         /* Delete deva from dpm_list and reinsert after devb. */
 150         list_move(&deva->power.entry, &devb->power.entry);
 151 }
 152
 153 /**
 154  * device_pm_move_last - Move device to end of the PM core's list of devices.
 155  * @dev: Device to move in dpm_list.
 156  */
 157 void device_pm_move_last(struct device *dev)
 158 {
 159         pr_debug("PM: Moving %s:%s to end of list\n",
 160                  dev->bus ? dev->bus->name : "No Bus",
 161                  kobject_name(&dev->kobj));
 162         list_move_tail(&dev->power.entry, &dpm_list);
 163 }
 164
 165 /**
 166  * pm_op - Execute the PM operation appropriate for given PM event.
 167  * @dev: Device to handle.
 168  * @ops: PM operations to choose from.
 169  * @state: PM transition of the system being carried out.
 170  */
 171 static int pm_op(struct device *dev,
 172                  const struct dev_pm_ops *ops,
 173                  pm_message_t state)
 174 {
 175         int error = 0;
 176         ktime_t calltime, delta, rettime;
 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         switch (state.event) {
 185 #ifdef CONFIG_SUSPEND
 186         case PM_EVENT_SUSPEND:
 187                 if (ops->suspend) {
 188                         error = ops->suspend(dev);
 189                         suspend_report_result(ops->suspend, error);
 190                 }
 191                 break;
 192         case PM_EVENT_RESUME:
 193                 if (ops->resume) {
 194                         error = ops->resume(dev);
 195                         suspend_report_result(ops->resume, error);
 196                 }
 197                 break;
 198 #endif /* CONFIG_SUSPEND */
 199 #ifdef CONFIG_HIBERNATION
 200         case PM_EVENT_FREEZE:
 201         case PM_EVENT_QUIESCE:
 202                 if (ops->freeze) {
 203                         error = ops->freeze(dev);
 204                         suspend_report_result(ops->freeze, error);
 205                 }
 206                 break;
 207         case PM_EVENT_HIBERNATE:
 208                 if (ops->poweroff) {
 209                         error = ops->poweroff(dev);
 210                         suspend_report_result(ops->poweroff, error);
 211                 }
 212                 break;
 213         case PM_EVENT_THAW:
 214         case PM_EVENT_RECOVER:
 215                 if (ops->thaw) {
 216                         error = ops->thaw(dev);
 217                         suspend_report_result(ops->thaw, error);
 218                 }
 219                 break;
 220         case PM_EVENT_RESTORE:
 221                 if (ops->restore) {
 222                         error = ops->restore(dev);
 223                         suspend_report_result(ops->restore, error);
 224                 }
 225                 break;
 226 #endif /* CONFIG_HIBERNATION */
 227         default:
 228                 error = -EINVAL;
 229         }
 230
 231         if (initcall_debug) {
 232                 rettime = ktime_get();
 233                 delta = ktime_sub(rettime, calltime);
 234                 pr_info("call %s+ returned %d after %Ld usecs\n", dev_name(dev),
 235                         error, (unsigned long long)ktime_to_ns(delta) >> 10);
 236         }
 237
 238         return error;
 239 }
 240
 241 /**
 242  * pm_noirq_op - Execute the PM operation appropriate for given PM event.
 243  * @dev: Device to handle.
 244  * @ops: PM operations to choose from.
 245  * @state: PM transition of the system being carried out.
 246  *
 247  * The driver of @dev will not receive interrupts while this function is being
 248  * executed.
 249  */
 250 static int pm_noirq_op(struct device *dev,
 251                         const struct dev_pm_ops *ops,
 252                         pm_message_t state)
 253 {
 254         int error = 0;
 255         ktime_t calltime, delta, rettime;
 256
 257         if (initcall_debug) {
 258                 pr_info("calling  %s_i+ @ %i\n",
 259                                 dev_name(dev), task_pid_nr(current));
 260                 calltime = ktime_get();
 261         }
 262
 263         switch (state.event) {
 264 #ifdef CONFIG_SUSPEND
 265         case PM_EVENT_SUSPEND:
 266                 if (ops->suspend_noirq) {
 267                         error = ops->suspend_noirq(dev);
 268                         suspend_report_result(ops->suspend_noirq, error);
 269                 }
 270                 break;
 271         case PM_EVENT_RESUME:
 272                 if (ops->resume_noirq) {
 273                         error = ops->resume_noirq(dev);
 274                         suspend_report_result(ops->resume_noirq, error);
 275                 }
 276                 break;
 277 #endif /* CONFIG_SUSPEND */
 278 #ifdef CONFIG_HIBERNATION
 279         case PM_EVENT_FREEZE:
 280         case PM_EVENT_QUIESCE:
 281                 if (ops->freeze_noirq) {
 282                         error = ops->freeze_noirq(dev);
 283                         suspend_report_result(ops->freeze_noirq, error);
 284                 }
 285                 break;
 286         case PM_EVENT_HIBERNATE:
 287                 if (ops->poweroff_noirq) {
 288                         error = ops->poweroff_noirq(dev);
 289                         suspend_report_result(ops->poweroff_noirq, error);
 290                 }
 291                 break;
 292         case PM_EVENT_THAW:
 293         case PM_EVENT_RECOVER:
 294                 if (ops->thaw_noirq) {
 295                         error = ops->thaw_noirq(dev);
 296                         suspend_report_result(ops->thaw_noirq, error);
 297                 }
 298                 break;
 299         case PM_EVENT_RESTORE:
 300                 if (ops->restore_noirq) {
 301                         error = ops->restore_noirq(dev);
 302                         suspend_report_result(ops->restore_noirq, error);
 303                 }
 304                 break;
 305 #endif /* CONFIG_HIBERNATION */
 306         default:
 307                 error = -EINVAL;
 308         }
 309
 310         if (initcall_debug) {
 311                 rettime = ktime_get();
 312                 delta = ktime_sub(rettime, calltime);
 313                 printk("initcall %s_i+ returned %d after %Ld usecs\n", dev_name(dev),
 314                         error, (unsigned long long)ktime_to_ns(delta) >> 10);
 315         }
 316
 317         return error;
 318 }
 319
 320 static char *pm_verb(int event)
 321 {
 322         switch (event) {
 323         case PM_EVENT_SUSPEND:
 324                 return "suspend";
 325         case PM_EVENT_RESUME:
 326                 return "resume";
 327         case PM_EVENT_FREEZE:
 328                 return "freeze";
 329         case PM_EVENT_QUIESCE:
 330                 return "quiesce";
 331         case PM_EVENT_HIBERNATE:
 332                 return "hibernate";
 333         case PM_EVENT_THAW:
 334                 return "thaw";
 335         case PM_EVENT_RESTORE:
 336                 return "restore";
 337         case PM_EVENT_RECOVER:
 338                 return "recover";
 339         default:
 340                 return "(unknown PM event)";
 341         }
 342 }
 343
 344 static void pm_dev_dbg(struct device *dev, pm_message_t state, char *info)
 345 {
 346         dev_dbg(dev, "%s%s%s\n", info, pm_verb(state.event),
 347                 ((state.event & PM_EVENT_SLEEP) && device_may_wakeup(dev)) ?
 348                 ", may wakeup" : "");
 349 }
 350
 351 static void pm_dev_err(struct device *dev, pm_message_t state, char *info,
 352                         int error)
 353 {
 354         printk(KERN_ERR "PM: Device %s failed to %s%s: error %d\n",
 355                 kobject_name(&dev->kobj), pm_verb(state.event), info, error);
 356 }
 357
 358 /*------------------------- Resume routines -------------------------*/
 359
 360 /**
 361  * device_resume_noirq - Execute an "early resume" callback for given device.
 362  * @dev: Device to handle.
 363  * @state: PM transition of the system being carried out.
 364  *
 365  * The driver of @dev will not receive interrupts while this function is being
 366  * executed.
 367  */
 368 static int device_resume_noirq(struct device *dev, pm_message_t state)
 369 {
 370         int error = 0;
 371
 372         TRACE_DEVICE(dev);
 373         TRACE_RESUME(0);
 374
 375         if (dev->bus && dev->bus->pm) {
 376                 pm_dev_dbg(dev, state, "EARLY ");
 377                 error = pm_noirq_op(dev, dev->bus->pm, state);
 378         }
 379
 380         TRACE_RESUME(error);
 381         return error;
 382 }
 383
 384 /**
 385  * dpm_resume_noirq - Execute "early resume" callbacks for non-sysdev devices.
 386  * @state: PM transition of the system being carried out.
 387  *
 388  * Call the "noirq" resume handlers for all devices marked as DPM_OFF_IRQ and
 389  * enable device drivers to receive interrupts.
 390  */
 391 void dpm_resume_noirq(pm_message_t state)
 392 {
 393         struct device *dev;
 394
 395         mutex_lock(&dpm_list_mtx);
 396         transition_started = false;
 397         list_for_each_entry(dev, &dpm_list, power.entry)
 398                 if (dev->power.status > DPM_OFF) {
 399                         int error;
 400
 401                         dev->power.status = DPM_OFF;
 402                         error = device_resume_noirq(dev, state);
 403                         if (error)
 404                                 pm_dev_err(dev, state, " early", error);
 405                 }
 406         mutex_unlock(&dpm_list_mtx);
 407         resume_device_irqs();
 408 }
 409 EXPORT_SYMBOL_GPL(dpm_resume_noirq);
 410
 411 /**
 412  * device_resume - Execute "resume" callbacks for given device.
 413  * @dev: Device to handle.
 414  * @state: PM transition of the system being carried out.
 415  */
 416 static int device_resume(struct device *dev, pm_message_t state)
 417 {
 418         int error = 0;
 419
 420         TRACE_DEVICE(dev);
 421         TRACE_RESUME(0);
 422
 423         down(&dev->sem);
 424
 425         if (dev->bus) {
 426                 if (dev->bus->pm) {
 427                         pm_dev_dbg(dev, state, "");
 428                         error = pm_op(dev, dev->bus->pm, state);
 429                 } else if (dev->bus->resume) {
 430                         pm_dev_dbg(dev, state, "legacy ");
 431                         error = dev->bus->resume(dev);
 432                 }
 433                 if (error)
 434                         goto End;
 435         }
 436
 437         if (dev->type) {
 438                 if (dev->type->pm) {
 439                         pm_dev_dbg(dev, state, "type ");
 440                         error = pm_op(dev, dev->type->pm, state);
 441                 }
 442                 if (error)
 443                         goto End;
 444         }
 445
 446         if (dev->class) {
 447                 if (dev->class->pm) {
 448                         pm_dev_dbg(dev, state, "class ");
 449                         error = pm_op(dev, dev->class->pm, state);
 450                 } else if (dev->class->resume) {
 451                         pm_dev_dbg(dev, state, "legacy class ");
 452                         error = dev->class->resume(dev);
 453                 }
 454         }
 455  End:
 456         up(&dev->sem);
 457
 458         TRACE_RESUME(error);
 459         return error;
 460 }
 461
 462 /**
 463  * dpm_resume - Execute "resume" callbacks for non-sysdev devices.
 464  * @state: PM transition of the system being carried out.
 465  *
 466  * Execute the appropriate "resume" callback for all devices whose status
 467  * indicates that they are suspended.
 468  */
 469 static void dpm_resume(pm_message_t state)
 470 {
 471         struct list_head list;
 472
 473         INIT_LIST_HEAD(&list);
 474         mutex_lock(&dpm_list_mtx);
 475         while (!list_empty(&dpm_list)) {
 476                 struct device *dev = to_device(dpm_list.next);
 477
 478                 get_device(dev);
 479                 if (dev->power.status >= DPM_OFF) {
 480                         int error;
 481
 482                         dev->power.status = DPM_RESUMING;
 483                         mutex_unlock(&dpm_list_mtx);
 484
 485                         error = device_resume(dev, state);
 486
 487                         mutex_lock(&dpm_list_mtx);
 488                         if (error)
 489                                 pm_dev_err(dev, state, "", error);
 490                 } else if (dev->power.status == DPM_SUSPENDING) {
 491                         /* Allow new children of the device to be registered */
 492                         dev->power.status = DPM_RESUMING;
 493                 }
 494                 if (!list_empty(&dev->power.entry))
 495                         list_move_tail(&dev->power.entry, &list);
 496                 put_device(dev);
 497         }
 498         list_splice(&list, &dpm_list);
 499         mutex_unlock(&dpm_list_mtx);
 500 }
 501
 502 /**
 503  * device_complete - Complete a PM transition for given device.
 504  * @dev: Device to handle.
 505  * @state: PM transition of the system being carried out.
 506  */
 507 static void device_complete(struct device *dev, pm_message_t state)
 508 {
 509         down(&dev->sem);
 510
 511         if (dev->class && dev->class->pm && dev->class->pm->complete) {
 512                 pm_dev_dbg(dev, state, "completing class ");
 513                 dev->class->pm->complete(dev);
 514         }
 515
 516         if (dev->type && dev->type->pm && dev->type->pm->complete) {
 517                 pm_dev_dbg(dev, state, "completing type ");
 518                 dev->type->pm->complete(dev);
 519         }
 520
 521         if (dev->bus && dev->bus->pm && dev->bus->pm->complete) {
 522                 pm_dev_dbg(dev, state, "completing ");
 523                 dev->bus->pm->complete(dev);
 524         }
 525
 526         up(&dev->sem);
 527 }
 528
 529 /**
 530  * dpm_complete - Complete a PM transition for all non-sysdev devices.
 531  * @state: PM transition of the system being carried out.
 532  *
 533  * Execute the ->complete() callbacks for all devices whose PM status is not
 534  * DPM_ON (this allows new devices to be registered).
 535  */
 536 static void dpm_complete(pm_message_t state)
 537 {
 538         struct list_head list;
 539
 540         INIT_LIST_HEAD(&list);
 541         mutex_lock(&dpm_list_mtx);
 542         transition_started = false;
 543         while (!list_empty(&dpm_list)) {
 544                 struct device *dev = to_device(dpm_list.prev);
 545
 546                 get_device(dev);
 547                 if (dev->power.status > DPM_ON) {
 548                         dev->power.status = DPM_ON;
 549                         mutex_unlock(&dpm_list_mtx);
 550
 551                         device_complete(dev, state);
 552                         pm_runtime_put_noidle(dev);
 553
 554                         mutex_lock(&dpm_list_mtx);
 555                 }
 556                 if (!list_empty(&dev->power.entry))
 557                         list_move(&dev->power.entry, &list);
 558                 put_device(dev);
 559         }
 560         list_splice(&list, &dpm_list);
 561         mutex_unlock(&dpm_list_mtx);
 562 }
 563
 564 /**
 565  * dpm_resume_end - Execute "resume" callbacks and complete system transition.
 566  * @state: PM transition of the system being carried out.
 567  *
 568  * Execute "resume" callbacks for all devices and complete the PM transition of
 569  * the system.
 570  */
 571 void dpm_resume_end(pm_message_t state)
 572 {
 573         might_sleep();
 574         dpm_resume(state);
 575         dpm_complete(state);
 576 }
 577 EXPORT_SYMBOL_GPL(dpm_resume_end);
 578
 579
 580 /*------------------------- Suspend routines -------------------------*/
 581
 582 /**
 583  * resume_event - Return a "resume" message for given "suspend" sleep state.
 584  * @sleep_state: PM message representing a sleep state.
 585  *
 586  * Return a PM message representing the resume event corresponding to given
 587  * sleep state.
 588  */
 589 static pm_message_t resume_event(pm_message_t sleep_state)
 590 {
 591         switch (sleep_state.event) {
 592         case PM_EVENT_SUSPEND:
 593                 return PMSG_RESUME;
 594         case PM_EVENT_FREEZE:
 595         case PM_EVENT_QUIESCE:
 596                 return PMSG_RECOVER;
 597         case PM_EVENT_HIBERNATE:
 598                 return PMSG_RESTORE;
 599         }
 600         return PMSG_ON;
 601 }
 602
 603 /**
 604  * device_suspend_noirq - Execute a "late suspend" callback for given device.
 605  * @dev: Device to handle.
 606  * @state: PM transition of the system being carried out.
 607  *
 608  * The driver of @dev will not receive interrupts while this function is being
 609  * executed.
 610  */
 611 static int device_suspend_noirq(struct device *dev, pm_message_t state)
 612 {
 613         int error = 0;
 614
 615         if (dev->bus && dev->bus->pm) {
 616                 pm_dev_dbg(dev, state, "LATE ");
 617                 error = pm_noirq_op(dev, dev->bus->pm, state);
 618         }
 619         return error;
 620 }
 621
 622 /**
 623  * dpm_suspend_noirq - Execute "late suspend" callbacks for non-sysdev devices.
 624  * @state: PM transition of the system being carried out.
 625  *
 626  * Prevent device drivers from receiving interrupts and call the "noirq" suspend
 627  * handlers for all non-sysdev devices.
 628  */
 629 int dpm_suspend_noirq(pm_message_t state)
 630 {
 631         struct device *dev;
 632         int error = 0;
 633
 634         suspend_device_irqs();
 635         mutex_lock(&dpm_list_mtx);
 636         list_for_each_entry_reverse(dev, &dpm_list, power.entry) {
 637                 error = device_suspend_noirq(dev, state);
 638                 if (error) {
 639                         pm_dev_err(dev, state, " late", error);
 640                         break;
 641                 }
 642                 dev->power.status = DPM_OFF_IRQ;
 643         }
 644         mutex_unlock(&dpm_list_mtx);
 645         if (error)
 646                 dpm_resume_noirq(resume_event(state));
 647         return error;
 648 }
 649 EXPORT_SYMBOL_GPL(dpm_suspend_noirq);
 650
 651 /**
 652  * device_suspend - Execute "suspend" callbacks for given device.
 653  * @dev: Device to handle.
 654  * @state: PM transition of the system being carried out.
 655  */
 656 static int device_suspend(struct device *dev, pm_message_t state)
 657 {
 658         int error = 0;
 659
 660         down(&dev->sem);
 661
 662         if (dev->class) {
 663                 if (dev->class->pm) {
 664                         pm_dev_dbg(dev, state, "class ");
 665                         error = pm_op(dev, dev->class->pm, state);
 666                 } else if (dev->class->suspend) {
 667                         pm_dev_dbg(dev, state, "legacy class ");
 668                         error = dev->class->suspend(dev, state);
 669                         suspend_report_result(dev->class->suspend, error);
 670                 }
 671                 if (error)
 672                         goto End;
 673         }
 674
 675         if (dev->type) {
 676                 if (dev->type->pm) {
 677                         pm_dev_dbg(dev, state, "type ");
 678                         error = pm_op(dev, dev->type->pm, state);
 679                 }
 680                 if (error)
 681                         goto End;
 682         }
 683
 684         if (dev->bus) {
 685                 if (dev->bus->pm) {
 686                         pm_dev_dbg(dev, state, "");
 687                         error = pm_op(dev, dev->bus->pm, state);
 688                 } else if (dev->bus->suspend) {
 689                         pm_dev_dbg(dev, state, "legacy ");
 690                         error = dev->bus->suspend(dev, state);
 691                         suspend_report_result(dev->bus->suspend, error);
 692                 }
 693         }
 694  End:
 695         up(&dev->sem);
 696
 697         return error;
 698 }
 699
 700 /**
 701  * dpm_suspend - Execute "suspend" callbacks for all non-sysdev devices.
 702  * @state: PM transition of the system being carried out.
 703  */
 704 static int dpm_suspend(pm_message_t state)
 705 {
 706         struct list_head list;
 707         int error = 0;
 708
 709         INIT_LIST_HEAD(&list);
 710         mutex_lock(&dpm_list_mtx);
 711         while (!list_empty(&dpm_list)) {
 712                 struct device *dev = to_device(dpm_list.prev);
 713
 714                 get_device(dev);
 715                 mutex_unlock(&dpm_list_mtx);
 716
 717                 error = device_suspend(dev, state);
 718
 719                 mutex_lock(&dpm_list_mtx);
 720                 if (error) {
 721                         pm_dev_err(dev, state, "", error);
 722                         put_device(dev);
 723                         break;
 724                 }
 725                 dev->power.status = DPM_OFF;
 726                 if (!list_empty(&dev->power.entry))
 727                         list_move(&dev->power.entry, &list);
 728                 put_device(dev);
 729         }
 730         list_splice(&list, dpm_list.prev);
 731         mutex_unlock(&dpm_list_mtx);
 732         return error;
 733 }
 734
 735 /**
 736  * device_prepare - Prepare a device for system power transition.
 737  * @dev: Device to handle.
 738  * @state: PM transition of the system being carried out.
 739  *
 740  * Execute the ->prepare() callback(s) for given device.  No new children of the
 741  * device may be registered after this function has returned.
 742  */
 743 static int device_prepare(struct device *dev, pm_message_t state)
 744 {
 745         int error = 0;
 746
 747         down(&dev->sem);
 748
 749         if (dev->bus && dev->bus->pm && dev->bus->pm->prepare) {
 750                 pm_dev_dbg(dev, state, "preparing ");
 751                 error = dev->bus->pm->prepare(dev);
 752                 suspend_report_result(dev->bus->pm->prepare, error);
 753                 if (error)
 754                         goto End;
 755         }
 756
 757         if (dev->type && dev->type->pm && dev->type->pm->prepare) {
 758                 pm_dev_dbg(dev, state, "preparing type ");
 759                 error = dev->type->pm->prepare(dev);
 760                 suspend_report_result(dev->type->pm->prepare, error);
 761                 if (error)
 762                         goto End;
 763         }
 764
 765         if (dev->class && dev->class->pm && dev->class->pm->prepare) {
 766                 pm_dev_dbg(dev, state, "preparing class ");
 767                 error = dev->class->pm->prepare(dev);
 768                 suspend_report_result(dev->class->pm->prepare, error);
 769         }
 770  End:
 771         up(&dev->sem);
 772
 773         return error;
 774 }
 775
 776 /**
 777  * dpm_prepare - Prepare all non-sysdev devices for a system PM transition.
 778  * @state: PM transition of the system being carried out.
 779  *
 780  * Execute the ->prepare() callback(s) for all devices.
 781  */
 782 static int dpm_prepare(pm_message_t state)
 783 {
 784         struct list_head list;
 785         int error = 0;
 786
 787         INIT_LIST_HEAD(&list);
 788         mutex_lock(&dpm_list_mtx);
 789         transition_started = true;
 790         while (!list_empty(&dpm_list)) {
 791                 struct device *dev = to_device(dpm_list.next);
 792
 793                 get_device(dev);
 794                 dev->power.status = DPM_PREPARING;
 795                 mutex_unlock(&dpm_list_mtx);
 796
 797                 pm_runtime_get_noresume(dev);
 798                 if (pm_runtime_barrier(dev) && device_may_wakeup(dev)) {
 799                         /* Wake-up requested during system sleep transition. */
 800                         pm_runtime_put_noidle(dev);
 801                         error = -EBUSY;
 802                 } else {
 803                         error = device_prepare(dev, state);
 804                 }
 805
 806                 mutex_lock(&dpm_list_mtx);
 807                 if (error) {
 808                         dev->power.status = DPM_ON;
 809                         if (error == -EAGAIN) {
 810                                 put_device(dev);
 811                                 error = 0;
 812                                 continue;
 813                         }
 814                         printk(KERN_ERR "PM: Failed to prepare device %s "
 815                                 "for power transition: error %d\n",
 816                                 kobject_name(&dev->kobj), error);
 817                         put_device(dev);
 818                         break;
 819                 }
 820                 dev->power.status = DPM_SUSPENDING;
 821                 if (!list_empty(&dev->power.entry))
 822                         list_move_tail(&dev->power.entry, &list);
 823                 put_device(dev);
 824         }
 825         list_splice(&list, &dpm_list);
 826         mutex_unlock(&dpm_list_mtx);
 827         return error;
 828 }
 829
 830 /**
 831  * dpm_suspend_start - Prepare devices for PM transition and suspend them.
 832  * @state: PM transition of the system being carried out.
 833  *
 834  * Prepare all non-sysdev devices for system PM transition and execute "suspend"
 835  * callbacks for them.
 836  */
 837 int dpm_suspend_start(pm_message_t state)
 838 {
 839         int error;
 840
 841         might_sleep();
 842         error = dpm_prepare(state);
 843         if (!error)
 844                 error = dpm_suspend(state);
 845         return error;
 846 }
 847 EXPORT_SYMBOL_GPL(dpm_suspend_start);
 848
 849 void __suspend_report_result(const char *function, void *fn, int ret)
 850 {
 851         if (ret)
 852                 printk(KERN_ERR "%s(): %pF returns %d\n", function, fn, ret);
 853 }
 854 EXPORT_SYMBOL_GPL(__suspend_report_result);