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 different set of lists than the global subsystem list are used to
  16  * keep track of power info because we use different lists to hold
  17  * devices based on what stage of the power management process they
  18  * are in. The power domain dependencies may also differ from the
  19  * ancestral dependencies that the subsystem list maintains.
  20  */
  21
  22 #include <linux/device.h>
  23 #include <linux/kallsyms.h>
  24 #include <linux/mutex.h>
  25 #include <linux/pm.h>
  26 #include <linux/resume-trace.h>
  27 #include <linux/rwsem.h>
  28
  29 #include "../base.h"
  30 #include "power.h"
  31
  32 /*
  33  * The entries in the dpm_active list are in a depth first order, simply
  34  * because children are guaranteed to be discovered after parents, and
  35  * are inserted at the back of the list on discovery.
  36  *
  37  * All the other lists are kept in the same order, for consistency.
  38  * However the lists aren't always traversed in the same order.
  39  * Semaphores must be acquired from the top (i.e., front) down
  40  * and released in the opposite order.  Devices must be suspended
  41  * from the bottom (i.e., end) up and resumed in the opposite order.
  42  * That way no parent will be suspended while it still has an active
  43  * child.
  44  *
  45  * Since device_pm_add() may be called with a device semaphore held,
  46  * we must never try to acquire a device semaphore while holding
  47  * dpm_list_mutex.
  48  */
  49
  50 LIST_HEAD(dpm_active);
  51 <<<<<<< HEAD:drivers/base/power/main.c
  52 static LIST_HEAD(dpm_locked);
  53 =======
  54 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
  55 static LIST_HEAD(dpm_off);
  56 static LIST_HEAD(dpm_off_irq);
  57 static LIST_HEAD(dpm_destroy);
  58
  59 static DEFINE_MUTEX(dpm_list_mtx);
  60
  61 static DECLARE_RWSEM(pm_sleep_rwsem);
  62
  63 int (*platform_enable_wakeup)(struct device *dev, int is_on);
  64
  65 /**
  66  *      device_pm_add - add a device to the list of active devices
  67  *      @dev:   Device to be added to the list
  68  */
  69 void device_pm_add(struct device *dev)
  70 {
  71         pr_debug("PM: Adding info for %s:%s\n",
  72                  dev->bus ? dev->bus->name : "No Bus",
  73                  kobject_name(&dev->kobj));
  74         mutex_lock(&dpm_list_mtx);
  75         list_add_tail(&dev->power.entry, &dpm_active);
  76         mutex_unlock(&dpm_list_mtx);
  77 }
  78
  79 /**
  80  *      device_pm_remove - remove a device from the list of active devices
  81  *      @dev:   Device to be removed from the list
  82  *
  83  *      This function also removes the device's PM-related sysfs attributes.
  84  */
  85 void device_pm_remove(struct device *dev)
  86 {
  87 <<<<<<< HEAD:drivers/base/power/main.c
  88         /*
  89          * If this function is called during a suspend, it will be blocked,
  90          * because we're holding the device's semaphore at that time, which may
  91          * lead to a deadlock.  In that case we want to print a warning.
  92          * However, it may also be called by unregister_dropped_devices() with
  93          * the device's semaphore released, in which case the warning should
  94          * not be printed.
  95          */
  96         if (down_trylock(&dev->sem)) {
  97                 if (down_read_trylock(&pm_sleep_rwsem)) {
  98                         /* No suspend in progress, wait on dev->sem */
  99                         down(&dev->sem);
 100                         up_read(&pm_sleep_rwsem);
 101                 } else {
 102                         /* Suspend in progress, we may deadlock */
 103                         dev_warn(dev, "Suspicious %s during suspend\n",
 104                                 __FUNCTION__);
 105                         dump_stack();
 106                         /* The user has been warned ... */
 107                         down(&dev->sem);
 108                 }
 109         }
 110 =======
 111 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
 112         pr_debug("PM: Removing info for %s:%s\n",
 113                  dev->bus ? dev->bus->name : "No Bus",
 114                  kobject_name(&dev->kobj));
 115         mutex_lock(&dpm_list_mtx);
 116         dpm_sysfs_remove(dev);
 117         list_del_init(&dev->power.entry);
 118         mutex_unlock(&dpm_list_mtx);
 119 <<<<<<< HEAD:drivers/base/power/main.c
 120         up(&dev->sem);
 121 =======
 122 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
 123 }
 124
 125 /**
 126  *      device_pm_schedule_removal - schedule the removal of a suspended device
 127  *      @dev:   Device to destroy
 128  *
 129  *      Moves the device to the dpm_destroy list for further processing by
 130  *      unregister_dropped_devices().
 131  */
 132 void device_pm_schedule_removal(struct device *dev)
 133 {
 134         pr_debug("PM: Preparing for removal: %s:%s\n",
 135                 dev->bus ? dev->bus->name : "No Bus",
 136                 kobject_name(&dev->kobj));
 137         mutex_lock(&dpm_list_mtx);
 138         list_move_tail(&dev->power.entry, &dpm_destroy);
 139         mutex_unlock(&dpm_list_mtx);
 140 }
 141 EXPORT_SYMBOL_GPL(device_pm_schedule_removal);
 142
 143 /**
 144  *      pm_sleep_lock - mutual exclusion for registration and suspend
 145  *
 146  *      Returns 0 if no suspend is underway and device registration
 147  *      may proceed, otherwise -EBUSY.
 148  */
 149 int pm_sleep_lock(void)
 150 {
 151         if (down_read_trylock(&pm_sleep_rwsem))
 152                 return 0;
 153
 154         return -EBUSY;
 155 }
 156
 157 /**
 158  *      pm_sleep_unlock - mutual exclusion for registration and suspend
 159  *
 160  *      This routine undoes the effect of device_pm_add_lock
 161  *      when a device's registration is complete.
 162  */
 163 void pm_sleep_unlock(void)
 164 {
 165         up_read(&pm_sleep_rwsem);
 166 }
 167
 168
 169 /*------------------------- Resume routines -------------------------*/
 170
 171 /**
 172  *      resume_device_early - Power on one device (early resume).
 173  *      @dev:   Device.
 174  *
 175  *      Must be called with interrupts disabled.
 176  */
 177 static int resume_device_early(struct device *dev)
 178 {
 179         int error = 0;
 180
 181         TRACE_DEVICE(dev);
 182         TRACE_RESUME(0);
 183
 184         if (dev->bus && dev->bus->resume_early) {
 185                 dev_dbg(dev, "EARLY resume\n");
 186                 error = dev->bus->resume_early(dev);
 187         }
 188
 189         TRACE_RESUME(error);
 190         return error;
 191 }
 192
 193 /**
 194  *      dpm_power_up - Power on all regular (non-sysdev) devices.
 195  *
 196  *      Walk the dpm_off_irq list and power each device up. This
 197  *      is used for devices that required they be powered down with
 198  *      interrupts disabled. As devices are powered on, they are moved
 199  *      to the dpm_off list.
 200  *
 201  *      Must be called with interrupts disabled and only one CPU running.
 202  */
 203 static void dpm_power_up(void)
 204 {
 205
 206         while (!list_empty(&dpm_off_irq)) {
 207                 struct list_head *entry = dpm_off_irq.next;
 208                 struct device *dev = to_device(entry);
 209
 210                 list_move_tail(entry, &dpm_off);
 211                 resume_device_early(dev);
 212         }
 213 }
 214
 215 /**
 216  *      device_power_up - Turn on all devices that need special attention.
 217  *
 218  *      Power on system devices, then devices that required we shut them down
 219  *      with interrupts disabled.
 220  *
 221  *      Must be called with interrupts disabled.
 222  */
 223 void device_power_up(void)
 224 {
 225         sysdev_resume();
 226         dpm_power_up();
 227 }
 228 EXPORT_SYMBOL_GPL(device_power_up);
 229
 230 /**
 231  *      resume_device - Restore state for one device.
 232  *      @dev:   Device.
 233  *
 234  */
 235 static int resume_device(struct device *dev)
 236 {
 237         int error = 0;
 238
 239         TRACE_DEVICE(dev);
 240         TRACE_RESUME(0);
 241
 242 <<<<<<< HEAD:drivers/base/power/main.c
 243 =======
 244         down(&dev->sem);
 245
 246 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
 247         if (dev->bus && dev->bus->resume) {
 248                 dev_dbg(dev,"resuming\n");
 249                 error = dev->bus->resume(dev);
 250         }
 251
 252         if (!error && dev->type && dev->type->resume) {
 253                 dev_dbg(dev,"resuming\n");
 254                 error = dev->type->resume(dev);
 255         }
 256
 257         if (!error && dev->class && dev->class->resume) {
 258                 dev_dbg(dev,"class resume\n");
 259                 error = dev->class->resume(dev);
 260         }
 261
 262 <<<<<<< HEAD:drivers/base/power/main.c
 263 =======
 264         up(&dev->sem);
 265
 266 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
 267         TRACE_RESUME(error);
 268         return error;
 269 }
 270
 271 /**
 272  *      dpm_resume - Resume every device.
 273  *
 274  *      Resume the devices that have either not gone through
 275  *      the late suspend, or that did go through it but also
 276  *      went through the early resume.
 277  *
 278  *      Take devices from the dpm_off_list, resume them,
 279  *      and put them on the dpm_locked list.
 280  */
 281 static void dpm_resume(void)
 282 {
 283         mutex_lock(&dpm_list_mtx);
 284         while(!list_empty(&dpm_off)) {
 285                 struct list_head *entry = dpm_off.next;
 286                 struct device *dev = to_device(entry);
 287
 288 <<<<<<< HEAD:drivers/base/power/main.c
 289                 list_move_tail(entry, &dpm_locked);
 290 =======
 291                 list_move_tail(entry, &dpm_active);
 292 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
 293                 mutex_unlock(&dpm_list_mtx);
 294                 resume_device(dev);
 295                 mutex_lock(&dpm_list_mtx);
 296         }
 297         mutex_unlock(&dpm_list_mtx);
 298 }
 299
 300 /**
 301 <<<<<<< HEAD:drivers/base/power/main.c
 302  *      unlock_all_devices - Release each device's semaphore
 303  *
 304  *      Go through the dpm_off list.  Put each device on the dpm_active
 305  *      list and unlock it.
 306  */
 307 static void unlock_all_devices(void)
 308 {
 309         mutex_lock(&dpm_list_mtx);
 310         while (!list_empty(&dpm_locked)) {
 311                 struct list_head *entry = dpm_locked.prev;
 312                 struct device *dev = to_device(entry);
 313
 314                 list_move(entry, &dpm_active);
 315                 up(&dev->sem);
 316         }
 317         mutex_unlock(&dpm_list_mtx);
 318 }
 319
 320 /**
 321 =======
 322 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
 323  *      unregister_dropped_devices - Unregister devices scheduled for removal
 324  *
 325  *      Unregister all devices on the dpm_destroy list.
 326  */
 327 static void unregister_dropped_devices(void)
 328 {
 329         mutex_lock(&dpm_list_mtx);
 330         while (!list_empty(&dpm_destroy)) {
 331                 struct list_head *entry = dpm_destroy.next;
 332                 struct device *dev = to_device(entry);
 333
 334 <<<<<<< HEAD:drivers/base/power/main.c
 335                 up(&dev->sem);
 336 =======
 337 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
 338                 mutex_unlock(&dpm_list_mtx);
 339                 /* This also removes the device from the list */
 340                 device_unregister(dev);
 341                 mutex_lock(&dpm_list_mtx);
 342         }
 343         mutex_unlock(&dpm_list_mtx);
 344 }
 345
 346 /**
 347  *      device_resume - Restore state of each device in system.
 348  *
 349  *      Resume all the devices, unlock them all, and allow new
 350  *      devices to be registered once again.
 351  */
 352 void device_resume(void)
 353 {
 354         might_sleep();
 355         dpm_resume();
 356 <<<<<<< HEAD:drivers/base/power/main.c
 357         unlock_all_devices();
 358 =======
 359 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
 360         unregister_dropped_devices();
 361         up_write(&pm_sleep_rwsem);
 362 }
 363 EXPORT_SYMBOL_GPL(device_resume);
 364
 365
 366 /*------------------------- Suspend routines -------------------------*/
 367
 368 static inline char *suspend_verb(u32 event)
 369 {
 370         switch (event) {
 371         case PM_EVENT_SUSPEND:  return "suspend";
 372         case PM_EVENT_FREEZE:   return "freeze";
 373         case PM_EVENT_PRETHAW:  return "prethaw";
 374         default:                return "(unknown suspend event)";
 375         }
 376 }
 377
 378 static void
 379 suspend_device_dbg(struct device *dev, pm_message_t state, char *info)
 380 {
 381         dev_dbg(dev, "%s%s%s\n", info, suspend_verb(state.event),
 382                 ((state.event == PM_EVENT_SUSPEND) && device_may_wakeup(dev)) ?
 383                 ", may wakeup" : "");
 384 }
 385
 386 /**
 387  *      suspend_device_late - Shut down one device (late suspend).
 388  *      @dev:   Device.
 389  *      @state: Power state device is entering.
 390  *
 391  *      This is called with interrupts off and only a single CPU running.
 392  */
 393 static int suspend_device_late(struct device *dev, pm_message_t state)
 394 {
 395         int error = 0;
 396
 397         if (dev->bus && dev->bus->suspend_late) {
 398                 suspend_device_dbg(dev, state, "LATE ");
 399                 error = dev->bus->suspend_late(dev, state);
 400                 suspend_report_result(dev->bus->suspend_late, error);
 401         }
 402         return error;
 403 }
 404
 405 /**
 406  *      device_power_down - Shut down special devices.
 407  *      @state:         Power state to enter.
 408  *
 409  *      Power down devices that require interrupts to be disabled
 410  *      and move them from the dpm_off list to the dpm_off_irq list.
 411  *      Then power down system devices.
 412  *
 413  *      Must be called with interrupts disabled and only one CPU running.
 414  */
 415 int device_power_down(pm_message_t state)
 416 {
 417         int error = 0;
 418
 419         while (!list_empty(&dpm_off)) {
 420                 struct list_head *entry = dpm_off.prev;
 421                 struct device *dev = to_device(entry);
 422
 423 <<<<<<< HEAD:drivers/base/power/main.c
 424                 list_del_init(&dev->power.entry);
 425 =======
 426 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
 427                 error = suspend_device_late(dev, state);
 428                 if (error) {
 429                         printk(KERN_ERR "Could not power down device %s: "
 430                                         "error %d\n",
 431                                         kobject_name(&dev->kobj), error);
 432 <<<<<<< HEAD:drivers/base/power/main.c
 433                         if (list_empty(&dev->power.entry))
 434                                 list_add(&dev->power.entry, &dpm_off);
 435 =======
 436 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
 437                         break;
 438                 }
 439 <<<<<<< HEAD:drivers/base/power/main.c
 440                 if (list_empty(&dev->power.entry))
 441                         list_add(&dev->power.entry, &dpm_off_irq);
 442 =======
 443                 if (!list_empty(&dev->power.entry))
 444                         list_move(&dev->power.entry, &dpm_off_irq);
 445 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
 446         }
 447
 448         if (!error)
 449                 error = sysdev_suspend(state);
 450         if (error)
 451                 dpm_power_up();
 452         return error;
 453 }
 454 EXPORT_SYMBOL_GPL(device_power_down);
 455
 456 /**
 457  *      suspend_device - Save state of one device.
 458  *      @dev:   Device.
 459  *      @state: Power state device is entering.
 460  */
 461 <<<<<<< HEAD:drivers/base/power/main.c
 462 int suspend_device(struct device *dev, pm_message_t state)
 463 =======
 464 static int suspend_device(struct device *dev, pm_message_t state)
 465 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
 466 {
 467         int error = 0;
 468
 469 <<<<<<< HEAD:drivers/base/power/main.c
 470 =======
 471         down(&dev->sem);
 472
 473 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
 474         if (dev->power.power_state.event) {
 475                 dev_dbg(dev, "PM: suspend %d-->%d\n",
 476                         dev->power.power_state.event, state.event);
 477         }
 478
 479         if (dev->class && dev->class->suspend) {
 480                 suspend_device_dbg(dev, state, "class ");
 481                 error = dev->class->suspend(dev, state);
 482                 suspend_report_result(dev->class->suspend, error);
 483         }
 484
 485         if (!error && dev->type && dev->type->suspend) {
 486                 suspend_device_dbg(dev, state, "type ");
 487                 error = dev->type->suspend(dev, state);
 488                 suspend_report_result(dev->type->suspend, error);
 489         }
 490
 491         if (!error && dev->bus && dev->bus->suspend) {
 492                 suspend_device_dbg(dev, state, "");
 493                 error = dev->bus->suspend(dev, state);
 494                 suspend_report_result(dev->bus->suspend, error);
 495         }
 496 <<<<<<< HEAD:drivers/base/power/main.c
 497 =======
 498
 499         up(&dev->sem);
 500
 501 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
 502         return error;
 503 }
 504
 505 /**
 506  *      dpm_suspend - Suspend every device.
 507  *      @state: Power state to put each device in.
 508  *
 509  *      Walk the dpm_locked list.  Suspend each device and move it
 510  *      to the dpm_off list.
 511  *
 512  *      (For historical reasons, if it returns -EAGAIN, that used to mean
 513  *      that the device would be called again with interrupts disabled.
 514  *      These days, we use the "suspend_late()" callback for that, so we
 515  *      print a warning and consider it an error).
 516  */
 517 static int dpm_suspend(pm_message_t state)
 518 {
 519         int error = 0;
 520
 521         mutex_lock(&dpm_list_mtx);
 522 <<<<<<< HEAD:drivers/base/power/main.c
 523         while (!list_empty(&dpm_locked)) {
 524                 struct list_head *entry = dpm_locked.prev;
 525 =======
 526         while (!list_empty(&dpm_active)) {
 527                 struct list_head *entry = dpm_active.prev;
 528 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
 529                 struct device *dev = to_device(entry);
 530
 531 <<<<<<< HEAD:drivers/base/power/main.c
 532                 list_del_init(&dev->power.entry);
 533 =======
 534 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
 535                 mutex_unlock(&dpm_list_mtx);
 536                 error = suspend_device(dev, state);
 537 <<<<<<< HEAD:drivers/base/power/main.c
 538 =======
 539                 mutex_lock(&dpm_list_mtx);
 540 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
 541                 if (error) {
 542                         printk(KERN_ERR "Could not suspend device %s: "
 543                                         "error %d%s\n",
 544                                         kobject_name(&dev->kobj),
 545                                         error,
 546                                         (error == -EAGAIN ?
 547                                         " (please convert to suspend_late)" :
 548                                         ""));
 549 <<<<<<< HEAD:drivers/base/power/main.c
 550                         mutex_lock(&dpm_list_mtx);
 551                         if (list_empty(&dev->power.entry))
 552                                 list_add(&dev->power.entry, &dpm_locked);
 553                         mutex_unlock(&dpm_list_mtx);
 554 =======
 555 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
 556                         break;
 557                 }
 558 <<<<<<< HEAD:drivers/base/power/main.c
 559                 mutex_lock(&dpm_list_mtx);
 560                 if (list_empty(&dev->power.entry))
 561                         list_add(&dev->power.entry, &dpm_off);
 562 =======
 563                 if (!list_empty(&dev->power.entry))
 564                         list_move(&dev->power.entry, &dpm_off);
 565 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
 566         }
 567         mutex_unlock(&dpm_list_mtx);
 568
 569         return error;
 570 }
 571
 572 /**
 573 <<<<<<< HEAD:drivers/base/power/main.c
 574  *      lock_all_devices - Acquire every device's semaphore
 575  *
 576  *      Go through the dpm_active list. Carefully lock each device's
 577  *      semaphore and put it in on the dpm_locked list.
 578  */
 579 static void lock_all_devices(void)
 580 {
 581         mutex_lock(&dpm_list_mtx);
 582         while (!list_empty(&dpm_active)) {
 583                 struct list_head *entry = dpm_active.next;
 584                 struct device *dev = to_device(entry);
 585
 586                 /* Required locking order is dev->sem first,
 587                  * then dpm_list_mutex.  Hence this awkward code.
 588                  */
 589                 get_device(dev);
 590                 mutex_unlock(&dpm_list_mtx);
 591                 down(&dev->sem);
 592                 mutex_lock(&dpm_list_mtx);
 593
 594                 if (list_empty(entry))
 595                         up(&dev->sem);          /* Device was removed */
 596                 else
 597                         list_move_tail(entry, &dpm_locked);
 598                 put_device(dev);
 599         }
 600         mutex_unlock(&dpm_list_mtx);
 601 }
 602
 603 /**
 604 =======
 605 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
 606  *      device_suspend - Save state and stop all devices in system.
 607 <<<<<<< HEAD:drivers/base/power/main.c
 608 =======
 609  *      @state: new power management state
 610 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
 611  *
 612  *      Prevent new devices from being registered, then lock all devices
 613  *      and suspend them.
 614  */
 615 int device_suspend(pm_message_t state)
 616 {
 617         int error;
 618
 619         might_sleep();
 620         down_write(&pm_sleep_rwsem);
 621 <<<<<<< HEAD:drivers/base/power/main.c
 622         lock_all_devices();
 623 =======
 624 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/base/power/main.c
 625         error = dpm_suspend(state);
 626         if (error)
 627                 device_resume();
 628         return error;
 629 }
 630 EXPORT_SYMBOL_GPL(device_suspend);
 631
 632 void __suspend_report_result(const char *function, void *fn, int ret)
 633 {
 634         if (ret) {
 635                 printk(KERN_ERR "%s(): ", function);
 636                 print_fn_descriptor_symbol("%s() returns ", (unsigned long)fn);
 637                 printk("%d\n", ret);
 638         }
 639 }
 640 EXPORT_SYMBOL_GPL(__suspend_report_result);