drivers/base/power/main.c

   1 /*
   2  * drivers/base/power/main.c - Where the driver meets power management.
   3  *
   4  * Copyright (c) 2003 Patrick Mochel
   5  * Copyright (c) 2003 Open Source Development Lab
   6  *
   7  * This file is released under the GPLv2
   8  *
   9  *
  10  * The driver model core calls device_pm_add() when a device is registered.
  11  * This will intialize the embedded device_pm_info object in the device
  12  * and add it to the list of power-controlled devices. sysfs entries for
  13  * controlling device power management will also be added.
  14  *
  15  * A separate list is used for keeping track of power info, because the power
  16  * domain dependencies may differ from the ancestral dependencies that the
  17  * subsystem list maintains.
  18  */
  19
  20 #include <linux/device.h>
  21 #include <linux/kallsyms.h>
  22 #include <linux/mutex.h>
  23 #include <linux/pm.h>
  24 #include <linux/pm_runtime.h>
  25 #include <linux/resume-trace.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/sched.h>
  28 #include <linux/async.h>
  29
  30 #include "../base.h"
  31 #include "power.h"
  32
  33 /*
  34  * The entries in the dpm_list list are in a depth first order, simply
  35  * because children are guaranteed to be discovered after parents, and
  36  * are inserted at the back of the list on discovery.
  37  *
  38  * Since device_pm_add() may be called with a device lock held,
  39  * we must never try to acquire a device lock while holding
  40  * dpm_list_mutex.
  41  */
  42
  43 LIST_HEAD(dpm_list);
  44
  45 static DEFINE_MUTEX(dpm_list_mtx);
  46 static pm_message_t pm_transition;
  47
  48 /*
  49  * Set once the preparation of devices for a PM transition has started, reset
  50  * before starting to resume devices.  Protected by dpm_list_mtx.
  51  */
  52 static bool transition_started;
  53
  54 /**
  55  * device_pm_init - Initialize the PM-related part of a device object.
  56  * @dev: Device object being initialized.
  57  */
  58 void device_pm_init(struct device *dev)
  59 {
  60         dev->power.status = DPM_ON;
  61         init_completion(&dev->power.completion);
  62         pm_runtime_init(dev);
  63 }
  64
  65 /**
  66  * device_pm_lock - Lock the list of active devices used by the PM core.
  67  */
  68 void device_pm_lock(void)
  69 {
  70         mutex_lock(&dpm_list_mtx);
  71 }
  72
  73 /**
  74  * device_pm_unlock - Unlock the list of active devices used by the PM core.
  75  */
  76 void device_pm_unlock(void)
  77 {
  78         mutex_unlock(&dpm_list_mtx);
  79 }
  80
  81 /**
  82  * device_pm_add - Add a device to the PM core's list of active devices.
  83  * @dev: Device to add to the list.
  84  */
  85 void device_pm_add(struct device *dev)
  86 {
  87         pr_debug("PM: Adding info for %s:%s\n",
  88                  dev->bus ? dev->bus->name : "No Bus",
  89                  kobject_name(&dev->kobj));
  90         mutex_lock(&dpm_list_mtx);
  91         if (dev->parent) {
  92                 if (dev->parent->power.status >= DPM_SUSPENDING)
  93                         dev_warn(dev, "parent %s should not be sleeping\n",
  94                                  dev_name(dev->parent));
  95         } else if (transition_started) {
  96                 /*
  97                  * We refuse to register parentless devices while a PM
  98                  * transition is in progress in order to avoid leaving them
  99                  * unhandled down the road
 100                  */
 101                 dev_WARN(dev, "Parentless device registered during a PM transaction\n");
 102         }
 103
 104         list_add_tail(&dev->power.entry, &dpm_list);
 105         mutex_unlock(&dpm_list_mtx);
 106 }
 107
 108 /**
 109  * device_pm_remove - Remove a device from the PM core's list of active devices.
 110  * @dev: Device to be removed from the list.
 111  */
 112 void device_pm_remove(struct device *dev)
 113 {
 114         pr_debug("PM: Removing info for %s:%s\n",
 115                  dev->bus ? dev->bus->name : "No Bus",
 116                  kobject_name(&dev->kobj));
 117         complete_all(&dev->power.completion);
 118         mutex_lock(&dpm_list_mtx);
 119         list_del_init(&dev->power.entry);
 120         mutex_unlock(&dpm_list_mtx);
 121         pm_runtime_remove(dev);
 122 }
 123
 124 /**
 125  * device_pm_move_before - Move device in the PM core's list of active devices.
 126  * @deva: Device to move in dpm_list.
 127  * @devb: Device @deva should come before.
 128  */
 129 void device_pm_move_before(struct device *deva, struct device *devb)
 130 {
 131         pr_debug("PM: Moving %s:%s before %s:%s\n",
 132                  deva->bus ? deva->bus->name : "No Bus",
 133                  kobject_name(&deva->kobj),
 134                  devb->bus ? devb->bus->name : "No Bus",
 135                  kobject_name(&devb->kobj));
 136         /* Delete deva from dpm_list and reinsert before devb. */
 137         list_move_tail(&deva->power.entry, &devb->power.entry);
 138 }
 139
 140 /**
 141  * device_pm_move_after - Move device in the PM core's list of active devices.
 142  * @deva: Device to move in dpm_list.
 143  * @devb: Device @deva should come after.
 144  */
 145 void device_pm_move_after(struct device *deva, struct device *devb)
 146 {
 147         pr_debug("PM: Moving %s:%s after %s:%s\n",
 148                  deva->bus ? deva->bus->name : "No Bus",
 149                  kobject_name(&deva->kobj),
 150                  devb->bus ? devb->bus->name : "No Bus",
 151                  kobject_name(&devb->kobj));
 152         /* Delete deva from dpm_list and reinsert after devb. */
 153         list_move(&deva->power.entry, &devb->power.entry);
 154 }
 155
 156 /**
 157  * device_pm_move_last - Move device to end of the PM core's list of devices.
 158  * @dev: Device to move in dpm_list.
 159  */
 160 void device_pm_move_last(struct device *dev)
 161 {
 162         pr_debug("PM: Moving %s:%s to end of list\n",
 163                  dev->bus ? dev->bus->name : "No Bus",
 164                  kobject_name(&dev->kobj));
 165         list_move_tail(&dev->power.entry, &dpm_list);
 166 }
 167
 168 static ktime_t initcall_debug_start(struct device *dev)
 169 {
 170         ktime_t calltime = ktime_set(0, 0);
 171
 172         if (initcall_debug) {
 173                 pr_info("calling  %s+ @ %i\n",
 174                                 dev_name(dev), task_pid_nr(current));
 175                 calltime = ktime_get();
 176         }
 177
 178         return calltime;
 179 }
 180
 181 static void initcall_debug_report(struct device *dev, ktime_t calltime,
 182                                   int error)
 183 {
 184         ktime_t delta, rettime;
 185
 186         if (initcall_debug) {
 187                 rettime = ktime_get();
 188                 delta = ktime_sub(rettime, calltime);
 189                 pr_info("call %s+ returned %d after %Ld usecs\n", dev_name(dev),
 190                         error, (unsigned long long)ktime_to_ns(delta) >> 10);
 191         }
 192 }
 193
 194 /**
 195  * dpm_wait - Wait for a PM operation to complete.
 196  * @dev: Device to wait for.
 197  * @async: If unset, wait only if the device's power.async_suspend flag is set.
 198  */
 199 static void dpm_wait(struct device *dev, bool async)
 200 {
 201         if (!dev)
 202                 return;
 203
 204         if (async || (pm_async_enabled && dev->power.async_suspend))
 205                 wait_for_completion(&dev->power.completion);
 206 }
 207
 208 static int dpm_wait_fn(struct device *dev, void *async_ptr)
 209 {
 210         dpm_wait(dev, *((bool *)async_ptr));
 211         return 0;
 212 }
 213
 214 static void dpm_wait_for_children(struct device *dev, bool async)
 215 {
 216        device_for_each_child(dev, &async, dpm_wait_fn);
 217 }
 218
 219 /**
 220  * pm_op - Execute the PM operation appropriate for given PM event.
 221  * @dev: Device to handle.
 222  * @ops: PM operations to choose from.
 223  * @state: PM transition of the system being carried out.
 224  */
 225 static int pm_op(struct device *dev,
 226                  const struct dev_pm_ops *ops,
 227                  pm_message_t state)
 228 {
 229         int error = 0;
 230         ktime_t calltime;
 231
 232         calltime = initcall_debug_start(dev);
 233
 234         switch (state.event) {
 235 #ifdef CONFIG_SUSPEND
 236         case PM_EVENT_SUSPEND:
 237                 if (ops->suspend) {
 238                         error = ops->suspend(dev);
 239                         suspend_report_result(ops->suspend, error);
 240                 }
 241                 break;
 242         case PM_EVENT_RESUME:
 243                 if (ops->resume) {
 244                         error = ops->resume(dev);
 245                         suspend_report_result(ops->resume, error);
 246                 }
 247                 break;
 248 #endif /* CONFIG_SUSPEND */
 249 #ifdef CONFIG_HIBERNATION
 250         case PM_EVENT_FREEZE:
 251         case PM_EVENT_QUIESCE:
 252                 if (ops->freeze) {
 253                         error = ops->freeze(dev);
 254                         suspend_report_result(ops->freeze, error);
 255                 }
 256                 break;
 257         case PM_EVENT_HIBERNATE:
 258                 if (ops->poweroff) {
 259                         error = ops->poweroff(dev);
 260                         suspend_report_result(ops->poweroff, error);
 261                 }
 262                 break;
 263         case PM_EVENT_THAW:
 264         case PM_EVENT_RECOVER:
 265                 if (ops->thaw) {
 266                         error = ops->thaw(dev);
 267                         suspend_report_result(ops->thaw, error);
 268                 }
 269                 break;
 270         case PM_EVENT_RESTORE:
 271                 if (ops->restore) {
 272                         error = ops->restore(dev);
 273                         suspend_report_result(ops->restore, error);
 274                 }
 275                 break;
 276 #endif /* CONFIG_HIBERNATION */
 277         default:
 278                 error = -EINVAL;
 279         }
 280
 281         initcall_debug_report(dev, calltime, error);
 282
 283         return error;
 284 }
 285
 286 /**
 287  * pm_noirq_op - Execute the PM operation appropriate for given PM event.
 288  * @dev: Device to handle.
 289  * @ops: PM operations to choose from.
 290  * @state: PM transition of the system being carried out.
 291  *
 292  * The driver of @dev will not receive interrupts while this function is being
 293  * executed.
 294  */
 295 static int pm_noirq_op(struct device *dev,
 296                         const struct dev_pm_ops *ops,
 297                         pm_message_t state)
 298 {
 299         int error = 0;
 300         ktime_t calltime, delta, rettime;
 301
 302         if (initcall_debug) {
 303                 pr_info("calling  %s+ @ %i, parent: %s\n",
 304                                 dev_name(dev), task_pid_nr(current),
 305                                 dev->parent ? dev_name(dev->parent) : "none");
 306                 calltime = ktime_get();
 307         }
 308
 309         switch (state.event) {
 310 #ifdef CONFIG_SUSPEND
 311         case PM_EVENT_SUSPEND:
 312                 if (ops->suspend_noirq) {
 313                         error = ops->suspend_noirq(dev);
 314                         suspend_report_result(ops->suspend_noirq, error);
 315                 }
 316                 break;
 317         case PM_EVENT_RESUME:
 318                 if (ops->resume_noirq) {
 319                         error = ops->resume_noirq(dev);
 320                         suspend_report_result(ops->resume_noirq, error);
 321                 }
 322                 break;
 323 #endif /* CONFIG_SUSPEND */
 324 #ifdef CONFIG_HIBERNATION
 325         case PM_EVENT_FREEZE:
 326         case PM_EVENT_QUIESCE:
 327                 if (ops->freeze_noirq) {
 328                         error = ops->freeze_noirq(dev);
 329                         suspend_report_result(ops->freeze_noirq, error);
 330                 }
 331                 break;
 332         case PM_EVENT_HIBERNATE:
 333                 if (ops->poweroff_noirq) {
 334                         error = ops->poweroff_noirq(dev);
 335                         suspend_report_result(ops->poweroff_noirq, error);
 336                 }
 337                 break;
 338         case PM_EVENT_THAW:
 339         case PM_EVENT_RECOVER:
 340                 if (ops->thaw_noirq) {
 341                         error = ops->thaw_noirq(dev);
 342                         suspend_report_result(ops->thaw_noirq, error);
 343                 }
 344                 break;
 345         case PM_EVENT_RESTORE:
 346                 if (ops->restore_noirq) {
 347                         error = ops->restore_noirq(dev);
 348                         suspend_report_result(ops->restore_noirq, error);
 349                 }
 350                 break;
 351 #endif /* CONFIG_HIBERNATION */
 352         default:
 353                 error = -EINVAL;
 354         }
 355
 356         if (initcall_debug) {
 357                 rettime = ktime_get();
 358                 delta = ktime_sub(rettime, calltime);
 359                 printk("initcall %s_i+ returned %d after %Ld usecs\n",
 360                         dev_name(dev), error,
 361                         (unsigned long long)ktime_to_ns(delta) >> 10);
 362         }
 363
 364         return error;
 365 }
 366
 367 static char *pm_verb(int event)
 368 {
 369         switch (event) {
 370         case PM_EVENT_SUSPEND:
 371                 return "suspend";
 372         case PM_EVENT_RESUME:
 373                 return "resume";
 374         case PM_EVENT_FREEZE:
 375                 return "freeze";
 376         case PM_EVENT_QUIESCE:
 377                 return "quiesce";
 378         case PM_EVENT_HIBERNATE:
 379                 return "hibernate";
 380         case PM_EVENT_THAW:
 381                 return "thaw";
 382         case PM_EVENT_RESTORE:
 383                 return "restore";
 384         case PM_EVENT_RECOVER:
 385                 return "recover";
 386         default:
 387                 return "(unknown PM event)";
 388         }
 389 }
 390
 391 static void pm_dev_dbg(struct device *dev, pm_message_t state, char *info)
 392 {
 393         dev_dbg(dev, "%s%s%s\n", info, pm_verb(state.event),
 394                 ((state.event & PM_EVENT_SLEEP) && device_may_wakeup(dev)) ?
 395                 ", may wakeup" : "");
 396 }
 397
 398 static void pm_dev_err(struct device *dev, pm_message_t state, char *info,
 399                         int error)
 400 {
 401         printk(KERN_ERR "PM: Device %s failed to %s%s: error %d\n",
 402                 kobject_name(&dev->kobj), pm_verb(state.event), info, error);
 403 }
 404
 405 static void dpm_show_time(ktime_t starttime, pm_message_t state, char *info)
 406 {
 407         ktime_t calltime;
 408         s64 usecs64;
 409         int usecs;
 410
 411         calltime = ktime_get();
 412         usecs64 = ktime_to_ns(ktime_sub(calltime, starttime));
 413         do_div(usecs64, NSEC_PER_USEC);
 414         usecs = usecs64;
 415         if (usecs == 0)
 416                 usecs = 1;
 417         pr_info("PM: %s%s%s of devices complete after %ld.%03ld msecs\n",
 418                 info ?: "", info ? " " : "", pm_verb(state.event),
 419                 usecs / USEC_PER_MSEC, usecs % USEC_PER_MSEC);
 420 }
 421
 422 /*------------------------- Resume routines -------------------------*/
 423
 424 /**
 425  * device_resume_noirq - Execute an "early resume" callback for given device.
 426  * @dev: Device to handle.
 427  * @state: PM transition of the system being carried out.
 428  *
 429  * The driver of @dev will not receive interrupts while this function is being
 430  * executed.
 431  */
 432 static int device_resume_noirq(struct device *dev, pm_message_t state)
 433 {
 434         int error = 0;
 435
 436         TRACE_DEVICE(dev);
 437         TRACE_RESUME(0);
 438
 439         if (dev->bus && dev->bus->pm) {
 440                 pm_dev_dbg(dev, state, "EARLY ");
 441                 error = pm_noirq_op(dev, dev->bus->pm, state);
 442                 if (error)
 443                         goto End;
 444         }
 445
 446         if (dev->type && dev->type->pm) {
 447                 pm_dev_dbg(dev, state, "EARLY type ");
 448                 error = pm_noirq_op(dev, dev->type->pm, state);
 449                 if (error)
 450                         goto End;
 451         }
 452
 453         if (dev->class && dev->class->pm) {
 454                 pm_dev_dbg(dev, state, "EARLY class ");
 455                 error = pm_noirq_op(dev, dev->class->pm, state);
 456         }
 457
 458 End:
 459         TRACE_RESUME(error);
 460         return error;
 461 }
 462
 463 /**
 464  * dpm_resume_noirq - Execute "early resume" callbacks for non-sysdev devices.
 465  * @state: PM transition of the system being carried out.
 466  *
 467  * Call the "noirq" resume handlers for all devices marked as DPM_OFF_IRQ and
 468  * enable device drivers to receive interrupts.
 469  */
 470 void dpm_resume_noirq(pm_message_t state)
 471 {
 472         struct device *dev;
 473         ktime_t starttime = ktime_get();
 474
 475         mutex_lock(&dpm_list_mtx);
 476         transition_started = false;
 477         list_for_each_entry(dev, &dpm_list, power.entry)
 478                 if (dev->power.status > DPM_OFF) {
 479                         int error;
 480
 481                         dev->power.status = DPM_OFF;
 482                         error = device_resume_noirq(dev, state);
 483                         if (error)
 484                                 pm_dev_err(dev, state, " early", error);
 485                 }
 486         mutex_unlock(&dpm_list_mtx);
 487         dpm_show_time(starttime, state, "early");
 488         resume_device_irqs();
 489 }
 490 EXPORT_SYMBOL_GPL(dpm_resume_noirq);
 491
 492 /**
 493  * legacy_resume - Execute a legacy (bus or class) resume callback for device.
 494  * @dev: Device to resume.
 495  * @cb: Resume callback to execute.
 496  */
 497 static int legacy_resume(struct device *dev, int (*cb)(struct device *dev))
 498 {
 499         int error;
 500         ktime_t calltime;
 501
 502         calltime = initcall_debug_start(dev);
 503
 504         error = cb(dev);
 505         suspend_report_result(cb, error);
 506
 507         initcall_debug_report(dev, calltime, error);
 508
 509         return error;
 510 }
 511
 512 /**
 513  * device_resume - Execute "resume" callbacks for given device.
 514  * @dev: Device to handle.
 515  * @state: PM transition of the system being carried out.
 516  * @async: If true, the device is being resumed asynchronously.
 517  */
 518 static int device_resume(struct device *dev, pm_message_t state, bool async)
 519 {
 520         int error = 0;
 521
 522         TRACE_DEVICE(dev);
 523         TRACE_RESUME(0);
 524
 525         dpm_wait(dev->parent, async);
 526         device_lock(dev);
 527
 528         dev->power.status = DPM_RESUMING;
 529
 530         if (dev->bus) {
 531                 if (dev->bus->pm) {
 532                         pm_dev_dbg(dev, state, "");
 533                         error = pm_op(dev, dev->bus->pm, state);
 534                 } else if (dev->bus->resume) {
 535                         pm_dev_dbg(dev, state, "legacy ");
 536                         error = legacy_resume(dev, dev->bus->resume);
 537                 }
 538                 if (error)
 539                         goto End;
 540         }
 541
 542         if (dev->type) {
 543                 if (dev->type->pm) {
 544                         pm_dev_dbg(dev, state, "type ");
 545                         error = pm_op(dev, dev->type->pm, state);
 546                 }
 547                 if (error)
 548                         goto End;
 549         }
 550
 551         if (dev->class) {
 552                 if (dev->class->pm) {
 553                         pm_dev_dbg(dev, state, "class ");
 554                         error = pm_op(dev, dev->class->pm, state);
 555                 } else if (dev->class->resume) {
 556                         pm_dev_dbg(dev, state, "legacy class ");
 557                         error = legacy_resume(dev, dev->class->resume);
 558                 }
 559         }
 560  End:
 561         device_unlock(dev);
 562         complete_all(&dev->power.completion);
 563
 564         TRACE_RESUME(error);
 565         return error;
 566 }
 567
 568 static void async_resume(void *data, async_cookie_t cookie)
 569 {
 570         struct device *dev = (struct device *)data;
 571         int error;
 572
 573         error = device_resume(dev, pm_transition, true);
 574         if (error)
 575                 pm_dev_err(dev, pm_transition, " async", error);
 576         put_device(dev);
 577 }
 578
 579 static bool is_async(struct device *dev)
 580 {
 581         return dev->power.async_suspend && pm_async_enabled
 582                 && !pm_trace_is_enabled();
 583 }
 584
 585 /**
 586  * dpm_resume - Execute "resume" callbacks for non-sysdev devices.
 587  * @state: PM transition of the system being carried out.
 588  *
 589  * Execute the appropriate "resume" callback for all devices whose status
 590  * indicates that they are suspended.
 591  */
 592 static void dpm_resume(pm_message_t state)
 593 {
 594         struct list_head list;
 595         struct device *dev;
 596         ktime_t starttime = ktime_get();
 597
 598         INIT_LIST_HEAD(&list);
 599         mutex_lock(&dpm_list_mtx);
 600         pm_transition = state;
 601
 602         list_for_each_entry(dev, &dpm_list, power.entry) {
 603                 if (dev->power.status < DPM_OFF)
 604                         continue;
 605
 606                 INIT_COMPLETION(dev->power.completion);
 607                 if (is_async(dev)) {
 608                         get_device(dev);
 609                         async_schedule(async_resume, dev);
 610                 }
 611         }
 612
 613         while (!list_empty(&dpm_list)) {
 614                 dev = to_device(dpm_list.next);
 615                 get_device(dev);
 616                 if (dev->power.status >= DPM_OFF && !is_async(dev)) {
 617                         int error;
 618
 619                         mutex_unlock(&dpm_list_mtx);
 620
 621                         error = device_resume(dev, state, false);
 622
 623                         mutex_lock(&dpm_list_mtx);
 624                         if (error)
 625                                 pm_dev_err(dev, state, "", error);
 626                 } else if (dev->power.status == DPM_SUSPENDING) {
 627                         /* Allow new children of the device to be registered */
 628                         dev->power.status = DPM_RESUMING;
 629                 }
 630                 if (!list_empty(&dev->power.entry))
 631                         list_move_tail(&dev->power.entry, &list);
 632                 put_device(dev);
 633         }
 634         list_splice(&list, &dpm_list);
 635         mutex_unlock(&dpm_list_mtx);
 636         async_synchronize_full();
 637         dpm_show_time(starttime, state, NULL);
 638 }
 639
 640 /**
 641  * device_complete - Complete a PM transition for given device.
 642  * @dev: Device to handle.
 643  * @state: PM transition of the system being carried out.
 644  */
 645 static void device_complete(struct device *dev, pm_message_t state)
 646 {
 647         device_lock(dev);
 648
 649         if (dev->class && dev->class->pm && dev->class->pm->complete) {
 650                 pm_dev_dbg(dev, state, "completing class ");
 651                 dev->class->pm->complete(dev);
 652         }
 653
 654         if (dev->type && dev->type->pm && dev->type->pm->complete) {
 655                 pm_dev_dbg(dev, state, "completing type ");
 656                 dev->type->pm->complete(dev);
 657         }
 658
 659         if (dev->bus && dev->bus->pm && dev->bus->pm->complete) {
 660                 pm_dev_dbg(dev, state, "completing ");
 661                 dev->bus->pm->complete(dev);
 662         }
 663
 664         device_unlock(dev);
 665 }
 666
 667 /**
 668  * dpm_complete - Complete a PM transition for all non-sysdev devices.
 669  * @state: PM transition of the system being carried out.
 670  *
 671  * Execute the ->complete() callbacks for all devices whose PM status is not
 672  * DPM_ON (this allows new devices to be registered).
 673  */
 674 static void dpm_complete(pm_message_t state)
 675 {
 676         struct list_head list;
 677
 678         INIT_LIST_HEAD(&list);
 679         mutex_lock(&dpm_list_mtx);
 680         transition_started = false;
 681         while (!list_empty(&dpm_list)) {
 682                 struct device *dev = to_device(dpm_list.prev);
 683
 684                 get_device(dev);
 685                 if (dev->power.status > DPM_ON) {
 686                         dev->power.status = DPM_ON;
 687                         mutex_unlock(&dpm_list_mtx);
 688
 689                         device_complete(dev, state);
 690                         pm_runtime_put_sync(dev);
 691
 692                         mutex_lock(&dpm_list_mtx);
 693                 }
 694                 if (!list_empty(&dev->power.entry))
 695                         list_move(&dev->power.entry, &list);
 696                 put_device(dev);
 697         }
 698         list_splice(&list, &dpm_list);
 699         mutex_unlock(&dpm_list_mtx);
 700 }
 701
 702 /**
 703  * dpm_resume_end - Execute "resume" callbacks and complete system transition.
 704  * @state: PM transition of the system being carried out.
 705  *
 706  * Execute "resume" callbacks for all devices and complete the PM transition of
 707  * the system.
 708  */
 709 void dpm_resume_end(pm_message_t state)
 710 {
 711         might_sleep();
 712         dpm_resume(state);
 713         dpm_complete(state);
 714 }
 715 EXPORT_SYMBOL_GPL(dpm_resume_end);
 716
 717
 718 /*------------------------- Suspend routines -------------------------*/
 719
 720 /**
 721  * resume_event - Return a "resume" message for given "suspend" sleep state.
 722  * @sleep_state: PM message representing a sleep state.
 723  *
 724  * Return a PM message representing the resume event corresponding to given
 725  * sleep state.
 726  */
 727 static pm_message_t resume_event(pm_message_t sleep_state)
 728 {
 729         switch (sleep_state.event) {
 730         case PM_EVENT_SUSPEND:
 731                 return PMSG_RESUME;
 732         case PM_EVENT_FREEZE:
 733         case PM_EVENT_QUIESCE:
 734                 return PMSG_RECOVER;
 735         case PM_EVENT_HIBERNATE:
 736                 return PMSG_RESTORE;
 737         }
 738         return PMSG_ON;
 739 }
 740
 741 /**
 742  * device_suspend_noirq - Execute a "late suspend" callback for given device.
 743  * @dev: Device to handle.
 744  * @state: PM transition of the system being carried out.
 745  *
 746  * The driver of @dev will not receive interrupts while this function is being
 747  * executed.
 748  */
 749 static int device_suspend_noirq(struct device *dev, pm_message_t state)
 750 {
 751         int error = 0;
 752
 753         if (dev->class && dev->class->pm) {
 754                 pm_dev_dbg(dev, state, "LATE class ");
 755                 error = pm_noirq_op(dev, dev->class->pm, state);
 756                 if (error)
 757                         goto End;
 758         }
 759
 760         if (dev->type && dev->type->pm) {
 761                 pm_dev_dbg(dev, state, "LATE type ");
 762                 error = pm_noirq_op(dev, dev->type->pm, state);
 763                 if (error)
 764                         goto End;
 765         }
 766
 767         if (dev->bus && dev->bus->pm) {
 768                 pm_dev_dbg(dev, state, "LATE ");
 769                 error = pm_noirq_op(dev, dev->bus->pm, state);
 770         }
 771
 772 End:
 773         return error;
 774 }
 775
 776 /**
 777  * dpm_suspend_noirq - Execute "late suspend" callbacks for non-sysdev devices.
 778  * @state: PM transition of the system being carried out.
 779  *
 780  * Prevent device drivers from receiving interrupts and call the "noirq" suspend
 781  * handlers for all non-sysdev devices.
 782  */
 783 int dpm_suspend_noirq(pm_message_t state)
 784 {
 785         struct device *dev;
 786         ktime_t starttime = ktime_get();
 787         int error = 0;
 788
 789         suspend_device_irqs();
 790         mutex_lock(&dpm_list_mtx);
 791         list_for_each_entry_reverse(dev, &dpm_list, power.entry) {
 792                 error = device_suspend_noirq(dev, state);
 793                 if (error) {
 794                         pm_dev_err(dev, state, " late", error);
 795                         break;
 796                 }
 797                 dev->power.status = DPM_OFF_IRQ;
 798         }
 799         mutex_unlock(&dpm_list_mtx);
 800         if (error)
 801                 dpm_resume_noirq(resume_event(state));
 802         else
 803                 dpm_show_time(starttime, state, "late");
 804         return error;
 805 }
 806 EXPORT_SYMBOL_GPL(dpm_suspend_noirq);
 807
 808 /**
 809  * legacy_suspend - Execute a legacy (bus or class) suspend callback for device.
 810  * @dev: Device to suspend.
 811  * @state: PM transition of the system being carried out.
 812  * @cb: Suspend callback to execute.
 813  */
 814 static int legacy_suspend(struct device *dev, pm_message_t state,
 815                           int (*cb)(struct device *dev, pm_message_t state))
 816 {
 817         int error;
 818         ktime_t calltime;
 819
 820         calltime = initcall_debug_start(dev);
 821
 822         error = cb(dev, state);
 823         suspend_report_result(cb, error);
 824
 825         initcall_debug_report(dev, calltime, error);
 826
 827         return error;
 828 }
 829
 830 static int async_error;
 831
 832 /**
 833  * device_suspend - Execute "suspend" callbacks for given device.
 834  * @dev: Device to handle.
 835  * @state: PM transition of the system being carried out.
 836  * @async: If true, the device is being suspended asynchronously.
 837  */
 838 static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 839 {
 840         int error = 0;
 841
 842         dpm_wait_for_children(dev, async);
 843         device_lock(dev);
 844
 845         if (async_error)
 846                 goto End;
 847
 848         if (dev->class) {
 849                 if (dev->class->pm) {
 850                         pm_dev_dbg(dev, state, "class ");
 851                         error = pm_op(dev, dev->class->pm, state);
 852                 } else if (dev->class->suspend) {
 853                         pm_dev_dbg(dev, state, "legacy class ");
 854                         error = legacy_suspend(dev, state, dev->class->suspend);
 855                 }
 856                 if (error)
 857                         goto End;
 858         }
 859
 860         if (dev->type) {
 861                 if (dev->type->pm) {
 862                         pm_dev_dbg(dev, state, "type ");
 863                         error = pm_op(dev, dev->type->pm, state);
 864                 }
 865                 if (error)
 866                         goto End;
 867         }
 868
 869         if (dev->bus) {
 870                 if (dev->bus->pm) {
 871                         pm_dev_dbg(dev, state, "");
 872                         error = pm_op(dev, dev->bus->pm, state);
 873                 } else if (dev->bus->suspend) {
 874                         pm_dev_dbg(dev, state, "legacy ");
 875                         error = legacy_suspend(dev, state, dev->bus->suspend);
 876                 }
 877         }
 878
 879         if (!error)
 880                 dev->power.status = DPM_OFF;
 881
 882  End:
 883         device_unlock(dev);
 884         complete_all(&dev->power.completion);
 885
 886         return error;
 887 }
 888
 889 static void async_suspend(void *data, async_cookie_t cookie)
 890 {
 891         struct device *dev = (struct device *)data;
 892         int error;
 893
 894         error = __device_suspend(dev, pm_transition, true);
 895         if (error) {
 896                 pm_dev_err(dev, pm_transition, " async", error);
 897                 async_error = error;
 898         }
 899
 900         put_device(dev);
 901 }
 902
 903 static int device_suspend(struct device *dev)
 904 {
 905         INIT_COMPLETION(dev->power.completion);
 906
 907         if (pm_async_enabled && dev->power.async_suspend) {
 908                 get_device(dev);
 909                 async_schedule(async_suspend, dev);
 910                 return 0;
 911         }
 912
 913         return __device_suspend(dev, pm_transition, false);
 914 }
 915
 916 /**
 917  * dpm_suspend - Execute "suspend" callbacks for all non-sysdev devices.
 918  * @state: PM transition of the system being carried out.
 919  */
 920 static int dpm_suspend(pm_message_t state)
 921 {
 922         struct list_head list;
 923         ktime_t starttime = ktime_get();
 924         int error = 0;
 925
 926         INIT_LIST_HEAD(&list);
 927         mutex_lock(&dpm_list_mtx);
 928         pm_transition = state;
 929         async_error = 0;
 930         while (!list_empty(&dpm_list)) {
 931                 struct device *dev = to_device(dpm_list.prev);
 932
 933                 get_device(dev);
 934                 mutex_unlock(&dpm_list_mtx);
 935
 936                 error = device_suspend(dev);
 937
 938                 mutex_lock(&dpm_list_mtx);
 939                 if (error) {
 940                         pm_dev_err(dev, state, "", error);
 941                         put_device(dev);
 942                         break;
 943                 }
 944                 if (!list_empty(&dev->power.entry))
 945                         list_move(&dev->power.entry, &list);
 946                 put_device(dev);
 947                 if (async_error)
 948                         break;
 949         }
 950         list_splice(&list, dpm_list.prev);
 951         mutex_unlock(&dpm_list_mtx);
 952         async_synchronize_full();
 953         if (!error)
 954                 error = async_error;
 955         if (!error)
 956                 dpm_show_time(starttime, state, NULL);
 957         return error;
 958 }
 959
 960 /**
 961  * device_prepare - Prepare a device for system power transition.
 962  * @dev: Device to handle.
 963  * @state: PM transition of the system being carried out.
 964  *
 965  * Execute the ->prepare() callback(s) for given device.  No new children of the
 966  * device may be registered after this function has returned.
 967  */
 968 static int device_prepare(struct device *dev, pm_message_t state)
 969 {
 970         int error = 0;
 971
 972         device_lock(dev);
 973
 974         if (dev->bus && dev->bus->pm && dev->bus->pm->prepare) {
 975                 pm_dev_dbg(dev, state, "preparing ");
 976                 error = dev->bus->pm->prepare(dev);
 977                 suspend_report_result(dev->bus->pm->prepare, error);
 978                 if (error)
 979                         goto End;
 980         }
 981
 982         if (dev->type && dev->type->pm && dev->type->pm->prepare) {
 983                 pm_dev_dbg(dev, state, "preparing type ");
 984                 error = dev->type->pm->prepare(dev);
 985                 suspend_report_result(dev->type->pm->prepare, error);
 986                 if (error)
 987                         goto End;
 988         }
 989
 990         if (dev->class && dev->class->pm && dev->class->pm->prepare) {
 991                 pm_dev_dbg(dev, state, "preparing class ");
 992                 error = dev->class->pm->prepare(dev);
 993                 suspend_report_result(dev->class->pm->prepare, error);
 994         }
 995  End:
 996         device_unlock(dev);
 997
 998         return error;
 999 }
1000
1001 /**
1002  * dpm_prepare - Prepare all non-sysdev devices for a system PM transition.
1003  * @state: PM transition of the system being carried out.
1004  *
1005  * Execute the ->prepare() callback(s) for all devices.
1006  */
1007 static int dpm_prepare(pm_message_t state)
1008 {
1009         struct list_head list;
1010         int error = 0;
1011
1012         INIT_LIST_HEAD(&list);
1013         mutex_lock(&dpm_list_mtx);
1014         transition_started = true;
1015         while (!list_empty(&dpm_list)) {
1016                 struct device *dev = to_device(dpm_list.next);
1017
1018                 get_device(dev);
1019                 dev->power.status = DPM_PREPARING;
1020                 mutex_unlock(&dpm_list_mtx);
1021
1022                 pm_runtime_get_noresume(dev);
1023                 if (pm_runtime_barrier(dev) && device_may_wakeup(dev)) {
1024                         /* Wake-up requested during system sleep transition. */
1025                         pm_runtime_put_sync(dev);
1026                         error = -EBUSY;
1027                 } else {
1028                         error = device_prepare(dev, state);
1029                 }
1030
1031                 mutex_lock(&dpm_list_mtx);
1032                 if (error) {
1033                         dev->power.status = DPM_ON;
1034                         if (error == -EAGAIN) {
1035                                 put_device(dev);
1036                                 error = 0;
1037                                 continue;
1038                         }
1039                         printk(KERN_ERR "PM: Failed to prepare device %s "
1040                                 "for power transition: error %d\n",
1041                                 kobject_name(&dev->kobj), error);
1042                         put_device(dev);
1043                         break;
1044                 }
1045                 dev->power.status = DPM_SUSPENDING;
1046                 if (!list_empty(&dev->power.entry))
1047                         list_move_tail(&dev->power.entry, &list);
1048                 put_device(dev);
1049         }
1050         list_splice(&list, &dpm_list);
1051         mutex_unlock(&dpm_list_mtx);
1052         return error;
1053 }
1054
1055 /**
1056  * dpm_suspend_start - Prepare devices for PM transition and suspend them.
1057  * @state: PM transition of the system being carried out.
1058  *
1059  * Prepare all non-sysdev devices for system PM transition and execute "suspend"
1060  * callbacks for them.
1061  */
1062 int dpm_suspend_start(pm_message_t state)
1063 {
1064         int error;
1065
1066         might_sleep();
1067         error = dpm_prepare(state);
1068         if (!error)
1069                 error = dpm_suspend(state);
1070         return error;
1071 }
1072 EXPORT_SYMBOL_GPL(dpm_suspend_start);
1073
1074 void __suspend_report_result(const char *function, void *fn, int ret)
1075 {
1076         if (ret)
1077                 printk(KERN_ERR "%s(): %pF returns %d\n", function, fn, ret);
1078 }
1079 EXPORT_SYMBOL_GPL(__suspend_report_result);
1080
1081 /**
1082  * device_pm_wait_for_dev - Wait for suspend/resume of a device to complete.
1083  * @dev: Device to wait for.
1084  * @subordinate: Device that needs to wait for @dev.
1085  */
1086 void device_pm_wait_for_dev(struct device *subordinate, struct device *dev)
1087 {
1088         dpm_wait(dev, subordinate->power.async_suspend);
1089 }
1090 EXPORT_SYMBOL_GPL(device_pm_wait_for_dev);