root/drivers/acpi/power.c

DEFINITIONS

1. to_power_resource
2. acpi_power_get_context
3. acpi_power_resources_list_add
4. acpi_power_resources_list_free
5. acpi_power_resource_is_dup
6. acpi_extract_power_resources
7. acpi_power_get_state
8. acpi_power_get_list_state
9. acpi_power_resource_add_dependent
10. acpi_power_resource_remove_dependent
11. acpi_device_power_add_dependent
12. acpi_device_power_remove_dependent
13. __acpi_power_on
14. acpi_power_on_unlocked
15. acpi_power_on
16. __acpi_power_off
17. acpi_power_off_unlocked
18. acpi_power_off
19. acpi_power_off_list
20. acpi_power_on_list
21. acpi_power_hide_list
22. acpi_power_expose_list
23. acpi_power_expose_hide
24. acpi_power_add_remove_device
25. acpi_power_wakeup_list_init
26. acpi_device_sleep_wake
27. acpi_enable_wakeup_device_power
28. acpi_disable_wakeup_device_power
29. acpi_power_get_inferred_state
30. acpi_power_on_resources
31. acpi_power_transition
32. acpi_release_power_resource
33. acpi_power_in_use_show
34. acpi_power_sysfs_remove
35. acpi_power_add_resource_to_list
36. acpi_add_power_resource
37. acpi_resume_power_resources
38. acpi_turn_off_unused_power_resources

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * drivers/acpi/power.c - ACPI Power Resources management.
   4  *
   5  * Copyright (C) 2001 - 2015 Intel Corp.
   6  * Author: Andy Grover <andrew.grover@intel.com>
   7  * Author: Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   8  * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
   9  */
  10 
  11 /*
  12  * ACPI power-managed devices may be controlled in two ways:
  13  * 1. via "Device Specific (D-State) Control"
  14  * 2. via "Power Resource Control".
  15  * The code below deals with ACPI Power Resources control.
  16  * 
  17  * An ACPI "power resource object" represents a software controllable power
  18  * plane, clock plane, or other resource depended on by a device.
  19  *
  20  * A device may rely on multiple power resources, and a power resource
  21  * may be shared by multiple devices.
  22  */
  23 
  24 #include <linux/kernel.h>
  25 #include <linux/module.h>
  26 #include <linux/init.h>
  27 #include <linux/types.h>
  28 #include <linux/slab.h>
  29 #include <linux/pm_runtime.h>
  30 #include <linux/sysfs.h>
  31 #include <linux/acpi.h>
  32 #include "sleep.h"
  33 #include "internal.h"
  34 
  35 #define _COMPONENT                      ACPI_POWER_COMPONENT
  36 ACPI_MODULE_NAME("power");
  37 #define ACPI_POWER_CLASS                "power_resource"
  38 #define ACPI_POWER_DEVICE_NAME          "Power Resource"
  39 #define ACPI_POWER_FILE_INFO            "info"
  40 #define ACPI_POWER_FILE_STATUS          "state"
  41 #define ACPI_POWER_RESOURCE_STATE_OFF   0x00
  42 #define ACPI_POWER_RESOURCE_STATE_ON    0x01
  43 #define ACPI_POWER_RESOURCE_STATE_UNKNOWN 0xFF
  44 
  45 struct acpi_power_dependent_device {
  46         struct device *dev;
  47         struct list_head node;
  48 };
  49 
  50 struct acpi_power_resource {
  51         struct acpi_device device;
  52         struct list_head list_node;
  53         char *name;
  54         u32 system_level;
  55         u32 order;
  56         unsigned int ref_count;
  57         bool wakeup_enabled;
  58         struct mutex resource_lock;
  59         struct list_head dependents;
  60 };
  61 
  62 struct acpi_power_resource_entry {
  63         struct list_head node;
  64         struct acpi_power_resource *resource;
  65 };
  66 
  67 static LIST_HEAD(acpi_power_resource_list);
  68 static DEFINE_MUTEX(power_resource_list_lock);
  69 
  70 /* --------------------------------------------------------------------------
  71                              Power Resource Management
  72    -------------------------------------------------------------------------- */
  73 
  74 static inline
  75 struct acpi_power_resource *to_power_resource(struct acpi_device *device)
  76 {
  77         return container_of(device, struct acpi_power_resource, device);
  78 }
  79 
  80 static struct acpi_power_resource *acpi_power_get_context(acpi_handle handle)
  81 {
  82         struct acpi_device *device;
  83 
  84         if (acpi_bus_get_device(handle, &device))
  85                 return NULL;
  86 
  87         return to_power_resource(device);
  88 }
  89 
  90 static int acpi_power_resources_list_add(acpi_handle handle,
  91                                          struct list_head *list)
  92 {
  93         struct acpi_power_resource *resource = acpi_power_get_context(handle);
  94         struct acpi_power_resource_entry *entry;
  95 
  96         if (!resource || !list)
  97                 return -EINVAL;
  98 
  99         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 100         if (!entry)
 101                 return -ENOMEM;
 102 
 103         entry->resource = resource;
 104         if (!list_empty(list)) {
 105                 struct acpi_power_resource_entry *e;
 106 
 107                 list_for_each_entry(e, list, node)
 108                         if (e->resource->order > resource->order) {
 109                                 list_add_tail(&entry->node, &e->node);
 110                                 return 0;
 111                         }
 112         }
 113         list_add_tail(&entry->node, list);
 114         return 0;
 115 }
 116 
 117 void acpi_power_resources_list_free(struct list_head *list)
 118 {
 119         struct acpi_power_resource_entry *entry, *e;
 120 
 121         list_for_each_entry_safe(entry, e, list, node) {
 122                 list_del(&entry->node);
 123                 kfree(entry);
 124         }
 125 }
 126 
 127 static bool acpi_power_resource_is_dup(union acpi_object *package,
 128                                        unsigned int start, unsigned int i)
 129 {
 130         acpi_handle rhandle, dup;
 131         unsigned int j;
 132 
 133         /* The caller is expected to check the package element types */
 134         rhandle = package->package.elements[i].reference.handle;
 135         for (j = start; j < i; j++) {
 136                 dup = package->package.elements[j].reference.handle;
 137                 if (dup == rhandle)
 138                         return true;
 139         }
 140 
 141         return false;
 142 }
 143 
 144 int acpi_extract_power_resources(union acpi_object *package, unsigned int start,
 145                                  struct list_head *list)
 146 {
 147         unsigned int i;
 148         int err = 0;
 149 
 150         for (i = start; i < package->package.count; i++) {
 151                 union acpi_object *element = &package->package.elements[i];
 152                 acpi_handle rhandle;
 153 
 154                 if (element->type != ACPI_TYPE_LOCAL_REFERENCE) {
 155                         err = -ENODATA;
 156                         break;
 157                 }
 158                 rhandle = element->reference.handle;
 159                 if (!rhandle) {
 160                         err = -ENODEV;
 161                         break;
 162                 }
 163 
 164                 /* Some ACPI tables contain duplicate power resource references */
 165                 if (acpi_power_resource_is_dup(package, start, i))
 166                         continue;
 167 
 168                 err = acpi_add_power_resource(rhandle);
 169                 if (err)
 170                         break;
 171 
 172                 err = acpi_power_resources_list_add(rhandle, list);
 173                 if (err)
 174                         break;
 175         }
 176         if (err)
 177                 acpi_power_resources_list_free(list);
 178 
 179         return err;
 180 }
 181 
 182 static int acpi_power_get_state(acpi_handle handle, int *state)
 183 {
 184         acpi_status status = AE_OK;
 185         unsigned long long sta = 0;
 186         char node_name[5];
 187         struct acpi_buffer buffer = { sizeof(node_name), node_name };
 188 
 189 
 190         if (!handle || !state)
 191                 return -EINVAL;
 192 
 193         status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
 194         if (ACPI_FAILURE(status))
 195                 return -ENODEV;
 196 
 197         *state = (sta & 0x01)?ACPI_POWER_RESOURCE_STATE_ON:
 198                               ACPI_POWER_RESOURCE_STATE_OFF;
 199 
 200         acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
 201 
 202         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] is %s\n",
 203                           node_name,
 204                                 *state ? "on" : "off"));
 205 
 206         return 0;
 207 }
 208 
 209 static int acpi_power_get_list_state(struct list_head *list, int *state)
 210 {
 211         struct acpi_power_resource_entry *entry;
 212         int cur_state;
 213 
 214         if (!list || !state)
 215                 return -EINVAL;
 216 
 217         /* The state of the list is 'on' IFF all resources are 'on'. */
 218         cur_state = 0;
 219         list_for_each_entry(entry, list, node) {
 220                 struct acpi_power_resource *resource = entry->resource;
 221                 acpi_handle handle = resource->device.handle;
 222                 int result;
 223 
 224                 mutex_lock(&resource->resource_lock);
 225                 result = acpi_power_get_state(handle, &cur_state);
 226                 mutex_unlock(&resource->resource_lock);
 227                 if (result)
 228                         return result;
 229 
 230                 if (cur_state != ACPI_POWER_RESOURCE_STATE_ON)
 231                         break;
 232         }
 233 
 234         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource list is %s\n",
 235                           cur_state ? "on" : "off"));
 236 
 237         *state = cur_state;
 238         return 0;
 239 }
 240 
 241 static int
 242 acpi_power_resource_add_dependent(struct acpi_power_resource *resource,
 243                                   struct device *dev)
 244 {
 245         struct acpi_power_dependent_device *dep;
 246         int ret = 0;
 247 
 248         mutex_lock(&resource->resource_lock);
 249         list_for_each_entry(dep, &resource->dependents, node) {
 250                 /* Only add it once */
 251                 if (dep->dev == dev)
 252                         goto unlock;
 253         }
 254 
 255         dep = kzalloc(sizeof(*dep), GFP_KERNEL);
 256         if (!dep) {
 257                 ret = -ENOMEM;
 258                 goto unlock;
 259         }
 260 
 261         dep->dev = dev;
 262         list_add_tail(&dep->node, &resource->dependents);
 263         dev_dbg(dev, "added power dependency to [%s]\n", resource->name);
 264 
 265 unlock:
 266         mutex_unlock(&resource->resource_lock);
 267         return ret;
 268 }
 269 
 270 static void
 271 acpi_power_resource_remove_dependent(struct acpi_power_resource *resource,
 272                                      struct device *dev)
 273 {
 274         struct acpi_power_dependent_device *dep;
 275 
 276         mutex_lock(&resource->resource_lock);
 277         list_for_each_entry(dep, &resource->dependents, node) {
 278                 if (dep->dev == dev) {
 279                         list_del(&dep->node);
 280                         kfree(dep);
 281                         dev_dbg(dev, "removed power dependency to [%s]\n",
 282                                 resource->name);
 283                         break;
 284                 }
 285         }
 286         mutex_unlock(&resource->resource_lock);
 287 }
 288 
 289 /**
 290  * acpi_device_power_add_dependent - Add dependent device of this ACPI device
 291  * @adev: ACPI device pointer
 292  * @dev: Dependent device
 293  *
 294  * If @adev has non-empty _PR0 the @dev is added as dependent device to all
 295  * power resources returned by it. This means that whenever these power
 296  * resources are turned _ON the dependent devices get runtime resumed. This
 297  * is needed for devices such as PCI to allow its driver to re-initialize
 298  * it after it went to D0uninitialized.
 299  *
 300  * If @adev does not have _PR0 this does nothing.
 301  *
 302  * Returns %0 in case of success and negative errno otherwise.
 303  */
 304 int acpi_device_power_add_dependent(struct acpi_device *adev,
 305                                     struct device *dev)
 306 {
 307         struct acpi_power_resource_entry *entry;
 308         struct list_head *resources;
 309         int ret;
 310 
 311         if (!adev->flags.power_manageable)
 312                 return 0;
 313 
 314         resources = &adev->power.states[ACPI_STATE_D0].resources;
 315         list_for_each_entry(entry, resources, node) {
 316                 ret = acpi_power_resource_add_dependent(entry->resource, dev);
 317                 if (ret)
 318                         goto err;
 319         }
 320 
 321         return 0;
 322 
 323 err:
 324         list_for_each_entry(entry, resources, node)
 325                 acpi_power_resource_remove_dependent(entry->resource, dev);
 326 
 327         return ret;
 328 }
 329 
 330 /**
 331  * acpi_device_power_remove_dependent - Remove dependent device
 332  * @adev: ACPI device pointer
 333  * @dev: Dependent device
 334  *
 335  * Does the opposite of acpi_device_power_add_dependent() and removes the
 336  * dependent device if it is found. Can be called to @adev that does not
 337  * have _PR0 as well.
 338  */
 339 void acpi_device_power_remove_dependent(struct acpi_device *adev,
 340                                         struct device *dev)
 341 {
 342         struct acpi_power_resource_entry *entry;
 343         struct list_head *resources;
 344 
 345         if (!adev->flags.power_manageable)
 346                 return;
 347 
 348         resources = &adev->power.states[ACPI_STATE_D0].resources;
 349         list_for_each_entry_reverse(entry, resources, node)
 350                 acpi_power_resource_remove_dependent(entry->resource, dev);
 351 }
 352 
 353 static int __acpi_power_on(struct acpi_power_resource *resource)
 354 {
 355         struct acpi_power_dependent_device *dep;
 356         acpi_status status = AE_OK;
 357 
 358         status = acpi_evaluate_object(resource->device.handle, "_ON", NULL, NULL);
 359         if (ACPI_FAILURE(status))
 360                 return -ENODEV;
 361 
 362         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Power resource [%s] turned on\n",
 363                           resource->name));
 364 
 365         /*
 366          * If there are other dependents on this power resource we need to
 367          * resume them now so that their drivers can re-initialize the
 368          * hardware properly after it went back to D0.
 369          */
 370         if (list_empty(&resource->dependents) ||
 371             list_is_singular(&resource->dependents))
 372                 return 0;
 373 
 374         list_for_each_entry(dep, &resource->dependents, node) {
 375                 dev_dbg(dep->dev, "runtime resuming because [%s] turned on\n",
 376                         resource->name);
 377                 pm_request_resume(dep->dev);
 378         }
 379 
 380         return 0;
 381 }
 382 
 383 static int acpi_power_on_unlocked(struct acpi_power_resource *resource)
 384 {
 385         int result = 0;
 386 
 387         if (resource->ref_count++) {
 388                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 389                                   "Power resource [%s] already on\n",
 390                                   resource->name));
 391         } else {
 392                 result = __acpi_power_on(resource);
 393                 if (result)
 394                         resource->ref_count--;
 395         }
 396         return result;
 397 }
 398 
 399 static int acpi_power_on(struct acpi_power_resource *resource)
 400 {
 401         int result;
 402 
 403         mutex_lock(&resource->resource_lock);
 404         result = acpi_power_on_unlocked(resource);
 405         mutex_unlock(&resource->resource_lock);
 406         return result;
 407 }
 408 
 409 static int __acpi_power_off(struct acpi_power_resource *resource)
 410 {
 411         acpi_status status;
 412 
 413         status = acpi_evaluate_object(resource->device.handle, "_OFF",
 414                                       NULL, NULL);
 415         if (ACPI_FAILURE(status))
 416                 return -ENODEV;
 417 
 418         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Power resource [%s] turned off\n",
 419                           resource->name));
 420         return 0;
 421 }
 422 
 423 static int acpi_power_off_unlocked(struct acpi_power_resource *resource)
 424 {
 425         int result = 0;
 426 
 427         if (!resource->ref_count) {
 428                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 429                                   "Power resource [%s] already off\n",
 430                                   resource->name));
 431                 return 0;
 432         }
 433 
 434         if (--resource->ref_count) {
 435                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 436                                   "Power resource [%s] still in use\n",
 437                                   resource->name));
 438         } else {
 439                 result = __acpi_power_off(resource);
 440                 if (result)
 441                         resource->ref_count++;
 442         }
 443         return result;
 444 }
 445 
 446 static int acpi_power_off(struct acpi_power_resource *resource)
 447 {
 448         int result;
 449 
 450         mutex_lock(&resource->resource_lock);
 451         result = acpi_power_off_unlocked(resource);
 452         mutex_unlock(&resource->resource_lock);
 453         return result;
 454 }
 455 
 456 static int acpi_power_off_list(struct list_head *list)
 457 {
 458         struct acpi_power_resource_entry *entry;
 459         int result = 0;
 460 
 461         list_for_each_entry_reverse(entry, list, node) {
 462                 result = acpi_power_off(entry->resource);
 463                 if (result)
 464                         goto err;
 465         }
 466         return 0;
 467 
 468  err:
 469         list_for_each_entry_continue(entry, list, node)
 470                 acpi_power_on(entry->resource);
 471 
 472         return result;
 473 }
 474 
 475 static int acpi_power_on_list(struct list_head *list)
 476 {
 477         struct acpi_power_resource_entry *entry;
 478         int result = 0;
 479 
 480         list_for_each_entry(entry, list, node) {
 481                 result = acpi_power_on(entry->resource);
 482                 if (result)
 483                         goto err;
 484         }
 485         return 0;
 486 
 487  err:
 488         list_for_each_entry_continue_reverse(entry, list, node)
 489                 acpi_power_off(entry->resource);
 490 
 491         return result;
 492 }
 493 
 494 static struct attribute *attrs[] = {
 495         NULL,
 496 };
 497 
 498 static const struct attribute_group attr_groups[] = {
 499         [ACPI_STATE_D0] = {
 500                 .name = "power_resources_D0",
 501                 .attrs = attrs,
 502         },
 503         [ACPI_STATE_D1] = {
 504                 .name = "power_resources_D1",
 505                 .attrs = attrs,
 506         },
 507         [ACPI_STATE_D2] = {
 508                 .name = "power_resources_D2",
 509                 .attrs = attrs,
 510         },
 511         [ACPI_STATE_D3_HOT] = {
 512                 .name = "power_resources_D3hot",
 513                 .attrs = attrs,
 514         },
 515 };
 516 
 517 static const struct attribute_group wakeup_attr_group = {
 518         .name = "power_resources_wakeup",
 519         .attrs = attrs,
 520 };
 521 
 522 static void acpi_power_hide_list(struct acpi_device *adev,
 523                                  struct list_head *resources,
 524                                  const struct attribute_group *attr_group)
 525 {
 526         struct acpi_power_resource_entry *entry;
 527 
 528         if (list_empty(resources))
 529                 return;
 530 
 531         list_for_each_entry_reverse(entry, resources, node) {
 532                 struct acpi_device *res_dev = &entry->resource->device;
 533 
 534                 sysfs_remove_link_from_group(&adev->dev.kobj,
 535                                              attr_group->name,
 536                                              dev_name(&res_dev->dev));
 537         }
 538         sysfs_remove_group(&adev->dev.kobj, attr_group);
 539 }
 540 
 541 static void acpi_power_expose_list(struct acpi_device *adev,
 542                                    struct list_head *resources,
 543                                    const struct attribute_group *attr_group)
 544 {
 545         struct acpi_power_resource_entry *entry;
 546         int ret;
 547 
 548         if (list_empty(resources))
 549                 return;
 550 
 551         ret = sysfs_create_group(&adev->dev.kobj, attr_group);
 552         if (ret)
 553                 return;
 554 
 555         list_for_each_entry(entry, resources, node) {
 556                 struct acpi_device *res_dev = &entry->resource->device;
 557 
 558                 ret = sysfs_add_link_to_group(&adev->dev.kobj,
 559                                               attr_group->name,
 560                                               &res_dev->dev.kobj,
 561                                               dev_name(&res_dev->dev));
 562                 if (ret) {
 563                         acpi_power_hide_list(adev, resources, attr_group);
 564                         break;
 565                 }
 566         }
 567 }
 568 
 569 static void acpi_power_expose_hide(struct acpi_device *adev,
 570                                    struct list_head *resources,
 571                                    const struct attribute_group *attr_group,
 572                                    bool expose)
 573 {
 574         if (expose)
 575                 acpi_power_expose_list(adev, resources, attr_group);
 576         else
 577                 acpi_power_hide_list(adev, resources, attr_group);
 578 }
 579 
 580 void acpi_power_add_remove_device(struct acpi_device *adev, bool add)
 581 {
 582         int state;
 583 
 584         if (adev->wakeup.flags.valid)
 585                 acpi_power_expose_hide(adev, &adev->wakeup.resources,
 586                                        &wakeup_attr_group, add);
 587 
 588         if (!adev->power.flags.power_resources)
 589                 return;
 590 
 591         for (state = ACPI_STATE_D0; state <= ACPI_STATE_D3_HOT; state++)
 592                 acpi_power_expose_hide(adev,
 593                                        &adev->power.states[state].resources,
 594                                        &attr_groups[state], add);
 595 }
 596 
 597 int acpi_power_wakeup_list_init(struct list_head *list, int *system_level_p)
 598 {
 599         struct acpi_power_resource_entry *entry;
 600         int system_level = 5;
 601 
 602         list_for_each_entry(entry, list, node) {
 603                 struct acpi_power_resource *resource = entry->resource;
 604                 acpi_handle handle = resource->device.handle;
 605                 int result;
 606                 int state;
 607 
 608                 mutex_lock(&resource->resource_lock);
 609 
 610                 result = acpi_power_get_state(handle, &state);
 611                 if (result) {
 612                         mutex_unlock(&resource->resource_lock);
 613                         return result;
 614                 }
 615                 if (state == ACPI_POWER_RESOURCE_STATE_ON) {
 616                         resource->ref_count++;
 617                         resource->wakeup_enabled = true;
 618                 }
 619                 if (system_level > resource->system_level)
 620                         system_level = resource->system_level;
 621 
 622                 mutex_unlock(&resource->resource_lock);
 623         }
 624         *system_level_p = system_level;
 625         return 0;
 626 }
 627 
 628 /* --------------------------------------------------------------------------
 629                              Device Power Management
 630    -------------------------------------------------------------------------- */
 631 
 632 /**
 633  * acpi_device_sleep_wake - execute _DSW (Device Sleep Wake) or (deprecated in
 634  *                          ACPI 3.0) _PSW (Power State Wake)
 635  * @dev: Device to handle.
 636  * @enable: 0 - disable, 1 - enable the wake capabilities of the device.
 637  * @sleep_state: Target sleep state of the system.
 638  * @dev_state: Target power state of the device.
 639  *
 640  * Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
 641  * State Wake) for the device, if present.  On failure reset the device's
 642  * wakeup.flags.valid flag.
 643  *
 644  * RETURN VALUE:
 645  * 0 if either _DSW or _PSW has been successfully executed
 646  * 0 if neither _DSW nor _PSW has been found
 647  * -ENODEV if the execution of either _DSW or _PSW has failed
 648  */
 649 int acpi_device_sleep_wake(struct acpi_device *dev,
 650                            int enable, int sleep_state, int dev_state)
 651 {
 652         union acpi_object in_arg[3];
 653         struct acpi_object_list arg_list = { 3, in_arg };
 654         acpi_status status = AE_OK;
 655 
 656         /*
 657          * Try to execute _DSW first.
 658          *
 659          * Three arguments are needed for the _DSW object:
 660          * Argument 0: enable/disable the wake capabilities
 661          * Argument 1: target system state
 662          * Argument 2: target device state
 663          * When _DSW object is called to disable the wake capabilities, maybe
 664          * the first argument is filled. The values of the other two arguments
 665          * are meaningless.
 666          */
 667         in_arg[0].type = ACPI_TYPE_INTEGER;
 668         in_arg[0].integer.value = enable;
 669         in_arg[1].type = ACPI_TYPE_INTEGER;
 670         in_arg[1].integer.value = sleep_state;
 671         in_arg[2].type = ACPI_TYPE_INTEGER;
 672         in_arg[2].integer.value = dev_state;
 673         status = acpi_evaluate_object(dev->handle, "_DSW", &arg_list, NULL);
 674         if (ACPI_SUCCESS(status)) {
 675                 return 0;
 676         } else if (status != AE_NOT_FOUND) {
 677                 printk(KERN_ERR PREFIX "_DSW execution failed\n");
 678                 dev->wakeup.flags.valid = 0;
 679                 return -ENODEV;
 680         }
 681 
 682         /* Execute _PSW */
 683         status = acpi_execute_simple_method(dev->handle, "_PSW", enable);
 684         if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {
 685                 printk(KERN_ERR PREFIX "_PSW execution failed\n");
 686                 dev->wakeup.flags.valid = 0;
 687                 return -ENODEV;
 688         }
 689 
 690         return 0;
 691 }
 692 
 693 /*
 694  * Prepare a wakeup device, two steps (Ref ACPI 2.0:P229):
 695  * 1. Power on the power resources required for the wakeup device 
 696  * 2. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
 697  *    State Wake) for the device, if present
 698  */
 699 int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state)
 700 {
 701         struct acpi_power_resource_entry *entry;
 702         int err = 0;
 703 
 704         if (!dev || !dev->wakeup.flags.valid)
 705                 return -EINVAL;
 706 
 707         mutex_lock(&acpi_device_lock);
 708 
 709         if (dev->wakeup.prepare_count++)
 710                 goto out;
 711 
 712         list_for_each_entry(entry, &dev->wakeup.resources, node) {
 713                 struct acpi_power_resource *resource = entry->resource;
 714 
 715                 mutex_lock(&resource->resource_lock);
 716 
 717                 if (!resource->wakeup_enabled) {
 718                         err = acpi_power_on_unlocked(resource);
 719                         if (!err)
 720                                 resource->wakeup_enabled = true;
 721                 }
 722 
 723                 mutex_unlock(&resource->resource_lock);
 724 
 725                 if (err) {
 726                         dev_err(&dev->dev,
 727                                 "Cannot turn wakeup power resources on\n");
 728                         dev->wakeup.flags.valid = 0;
 729                         goto out;
 730                 }
 731         }
 732         /*
 733          * Passing 3 as the third argument below means the device may be
 734          * put into arbitrary power state afterward.
 735          */
 736         err = acpi_device_sleep_wake(dev, 1, sleep_state, 3);
 737         if (err)
 738                 dev->wakeup.prepare_count = 0;
 739 
 740  out:
 741         mutex_unlock(&acpi_device_lock);
 742         return err;
 743 }
 744 
 745 /*
 746  * Shutdown a wakeup device, counterpart of above method
 747  * 1. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
 748  *    State Wake) for the device, if present
 749  * 2. Shutdown down the power resources
 750  */
 751 int acpi_disable_wakeup_device_power(struct acpi_device *dev)
 752 {
 753         struct acpi_power_resource_entry *entry;
 754         int err = 0;
 755 
 756         if (!dev || !dev->wakeup.flags.valid)
 757                 return -EINVAL;
 758 
 759         mutex_lock(&acpi_device_lock);
 760 
 761         if (--dev->wakeup.prepare_count > 0)
 762                 goto out;
 763 
 764         /*
 765          * Executing the code below even if prepare_count is already zero when
 766          * the function is called may be useful, for example for initialisation.
 767          */
 768         if (dev->wakeup.prepare_count < 0)
 769                 dev->wakeup.prepare_count = 0;
 770 
 771         err = acpi_device_sleep_wake(dev, 0, 0, 0);
 772         if (err)
 773                 goto out;
 774 
 775         list_for_each_entry(entry, &dev->wakeup.resources, node) {
 776                 struct acpi_power_resource *resource = entry->resource;
 777 
 778                 mutex_lock(&resource->resource_lock);
 779 
 780                 if (resource->wakeup_enabled) {
 781                         err = acpi_power_off_unlocked(resource);
 782                         if (!err)
 783                                 resource->wakeup_enabled = false;
 784                 }
 785 
 786                 mutex_unlock(&resource->resource_lock);
 787 
 788                 if (err) {
 789                         dev_err(&dev->dev,
 790                                 "Cannot turn wakeup power resources off\n");
 791                         dev->wakeup.flags.valid = 0;
 792                         break;
 793                 }
 794         }
 795 
 796  out:
 797         mutex_unlock(&acpi_device_lock);
 798         return err;
 799 }
 800 
 801 int acpi_power_get_inferred_state(struct acpi_device *device, int *state)
 802 {
 803         int result = 0;
 804         int list_state = 0;
 805         int i = 0;
 806 
 807         if (!device || !state)
 808                 return -EINVAL;
 809 
 810         /*
 811          * We know a device's inferred power state when all the resources
 812          * required for a given D-state are 'on'.
 813          */
 814         for (i = ACPI_STATE_D0; i <= ACPI_STATE_D3_HOT; i++) {
 815                 struct list_head *list = &device->power.states[i].resources;
 816 
 817                 if (list_empty(list))
 818                         continue;
 819 
 820                 result = acpi_power_get_list_state(list, &list_state);
 821                 if (result)
 822                         return result;
 823 
 824                 if (list_state == ACPI_POWER_RESOURCE_STATE_ON) {
 825                         *state = i;
 826                         return 0;
 827                 }
 828         }
 829 
 830         *state = device->power.states[ACPI_STATE_D3_COLD].flags.valid ?
 831                 ACPI_STATE_D3_COLD : ACPI_STATE_D3_HOT;
 832         return 0;
 833 }
 834 
 835 int acpi_power_on_resources(struct acpi_device *device, int state)
 836 {
 837         if (!device || state < ACPI_STATE_D0 || state > ACPI_STATE_D3_HOT)
 838                 return -EINVAL;
 839 
 840         return acpi_power_on_list(&device->power.states[state].resources);
 841 }
 842 
 843 int acpi_power_transition(struct acpi_device *device, int state)
 844 {
 845         int result = 0;
 846 
 847         if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD))
 848                 return -EINVAL;
 849 
 850         if (device->power.state == state || !device->flags.power_manageable)
 851                 return 0;
 852 
 853         if ((device->power.state < ACPI_STATE_D0)
 854             || (device->power.state > ACPI_STATE_D3_COLD))
 855                 return -ENODEV;
 856 
 857         /*
 858          * First we reference all power resources required in the target list
 859          * (e.g. so the device doesn't lose power while transitioning).  Then,
 860          * we dereference all power resources used in the current list.
 861          */
 862         if (state < ACPI_STATE_D3_COLD)
 863                 result = acpi_power_on_list(
 864                         &device->power.states[state].resources);
 865 
 866         if (!result && device->power.state < ACPI_STATE_D3_COLD)
 867                 acpi_power_off_list(
 868                         &device->power.states[device->power.state].resources);
 869 
 870         /* We shouldn't change the state unless the above operations succeed. */
 871         device->power.state = result ? ACPI_STATE_UNKNOWN : state;
 872 
 873         return result;
 874 }
 875 
 876 static void acpi_release_power_resource(struct device *dev)
 877 {
 878         struct acpi_device *device = to_acpi_device(dev);
 879         struct acpi_power_resource *resource;
 880 
 881         resource = container_of(device, struct acpi_power_resource, device);
 882 
 883         mutex_lock(&power_resource_list_lock);
 884         list_del(&resource->list_node);
 885         mutex_unlock(&power_resource_list_lock);
 886 
 887         acpi_free_pnp_ids(&device->pnp);
 888         kfree(resource);
 889 }
 890 
 891 static ssize_t acpi_power_in_use_show(struct device *dev,
 892                                       struct device_attribute *attr,
 893                                       char *buf) {
 894         struct acpi_power_resource *resource;
 895 
 896         resource = to_power_resource(to_acpi_device(dev));
 897         return sprintf(buf, "%u\n", !!resource->ref_count);
 898 }
 899 static DEVICE_ATTR(resource_in_use, 0444, acpi_power_in_use_show, NULL);
 900 
 901 static void acpi_power_sysfs_remove(struct acpi_device *device)
 902 {
 903         device_remove_file(&device->dev, &dev_attr_resource_in_use);
 904 }
 905 
 906 static void acpi_power_add_resource_to_list(struct acpi_power_resource *resource)
 907 {
 908         mutex_lock(&power_resource_list_lock);
 909 
 910         if (!list_empty(&acpi_power_resource_list)) {
 911                 struct acpi_power_resource *r;
 912 
 913                 list_for_each_entry(r, &acpi_power_resource_list, list_node)
 914                         if (r->order > resource->order) {
 915                                 list_add_tail(&resource->list_node, &r->list_node);
 916                                 goto out;
 917                         }
 918         }
 919         list_add_tail(&resource->list_node, &acpi_power_resource_list);
 920 
 921  out:
 922         mutex_unlock(&power_resource_list_lock);
 923 }
 924 
 925 int acpi_add_power_resource(acpi_handle handle)
 926 {
 927         struct acpi_power_resource *resource;
 928         struct acpi_device *device = NULL;
 929         union acpi_object acpi_object;
 930         struct acpi_buffer buffer = { sizeof(acpi_object), &acpi_object };
 931         acpi_status status;
 932         int state, result = -ENODEV;
 933 
 934         acpi_bus_get_device(handle, &device);
 935         if (device)
 936                 return 0;
 937 
 938         resource = kzalloc(sizeof(*resource), GFP_KERNEL);
 939         if (!resource)
 940                 return -ENOMEM;
 941 
 942         device = &resource->device;
 943         acpi_init_device_object(device, handle, ACPI_BUS_TYPE_POWER,
 944                                 ACPI_STA_DEFAULT);
 945         mutex_init(&resource->resource_lock);
 946         INIT_LIST_HEAD(&resource->list_node);
 947         INIT_LIST_HEAD(&resource->dependents);
 948         resource->name = device->pnp.bus_id;
 949         strcpy(acpi_device_name(device), ACPI_POWER_DEVICE_NAME);
 950         strcpy(acpi_device_class(device), ACPI_POWER_CLASS);
 951         device->power.state = ACPI_STATE_UNKNOWN;
 952 
 953         /* Evalute the object to get the system level and resource order. */
 954         status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
 955         if (ACPI_FAILURE(status))
 956                 goto err;
 957 
 958         resource->system_level = acpi_object.power_resource.system_level;
 959         resource->order = acpi_object.power_resource.resource_order;
 960 
 961         result = acpi_power_get_state(handle, &state);
 962         if (result)
 963                 goto err;
 964 
 965         printk(KERN_INFO PREFIX "%s [%s] (%s)\n", acpi_device_name(device),
 966                acpi_device_bid(device), state ? "on" : "off");
 967 
 968         device->flags.match_driver = true;
 969         result = acpi_device_add(device, acpi_release_power_resource);
 970         if (result)
 971                 goto err;
 972 
 973         if (!device_create_file(&device->dev, &dev_attr_resource_in_use))
 974                 device->remove = acpi_power_sysfs_remove;
 975 
 976         acpi_power_add_resource_to_list(resource);
 977         acpi_device_add_finalize(device);
 978         return 0;
 979 
 980  err:
 981         acpi_release_power_resource(&device->dev);
 982         return result;
 983 }
 984 
 985 #ifdef CONFIG_ACPI_SLEEP
 986 void acpi_resume_power_resources(void)
 987 {
 988         struct acpi_power_resource *resource;
 989 
 990         mutex_lock(&power_resource_list_lock);
 991 
 992         list_for_each_entry(resource, &acpi_power_resource_list, list_node) {
 993                 int result, state;
 994 
 995                 mutex_lock(&resource->resource_lock);
 996 
 997                 result = acpi_power_get_state(resource->device.handle, &state);
 998                 if (result) {
 999                         mutex_unlock(&resource->resource_lock);
1000                         continue;
1001                 }
1002 
1003                 if (state == ACPI_POWER_RESOURCE_STATE_OFF
1004                     && resource->ref_count) {
1005                         dev_info(&resource->device.dev, "Turning ON\n");
1006                         __acpi_power_on(resource);
1007                 }
1008 
1009                 mutex_unlock(&resource->resource_lock);
1010         }
1011 
1012         mutex_unlock(&power_resource_list_lock);
1013 }
1014 
1015 void acpi_turn_off_unused_power_resources(void)
1016 {
1017         struct acpi_power_resource *resource;
1018 
1019         mutex_lock(&power_resource_list_lock);
1020 
1021         list_for_each_entry_reverse(resource, &acpi_power_resource_list, list_node) {
1022                 int result, state;
1023 
1024                 mutex_lock(&resource->resource_lock);
1025 
1026                 result = acpi_power_get_state(resource->device.handle, &state);
1027                 if (result) {
1028                         mutex_unlock(&resource->resource_lock);
1029                         continue;
1030                 }
1031 
1032                 if (state == ACPI_POWER_RESOURCE_STATE_ON
1033                     && !resource->ref_count) {
1034                         dev_info(&resource->device.dev, "Turning OFF\n");
1035                         __acpi_power_off(resource);
1036                 }
1037 
1038                 mutex_unlock(&resource->resource_lock);
1039         }
1040 
1041         mutex_unlock(&power_resource_list_lock);
1042 }
1043 #endif