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