drivers/base/power/main.c

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