linux/drivers/acpi/power.c
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   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#define pr_fmt(fmt) "ACPI: PM: " fmt
  25
  26#include <linux/kernel.h>
  27#include <linux/module.h>
  28#include <linux/init.h>
  29#include <linux/types.h>
  30#include <linux/slab.h>
  31#include <linux/pm_runtime.h>
  32#include <linux/sysfs.h>
  33#include <linux/acpi.h>
  34#include "sleep.h"
  35#include "internal.h"
  36
  37#define ACPI_POWER_CLASS                "power_resource"
  38#define ACPI_POWER_DEVICE_NAME          "Power Resource"
  39#define ACPI_POWER_RESOURCE_STATE_OFF   0x00
  40#define ACPI_POWER_RESOURCE_STATE_ON    0x01
  41#define ACPI_POWER_RESOURCE_STATE_UNKNOWN 0xFF
  42
  43struct acpi_power_dependent_device {
  44        struct device *dev;
  45        struct list_head node;
  46};
  47
  48struct acpi_power_resource {
  49        struct acpi_device device;
  50        struct list_head list_node;
  51        char *name;
  52        u32 system_level;
  53        u32 order;
  54        unsigned int ref_count;
  55        unsigned int users;
  56        bool wakeup_enabled;
  57        struct mutex resource_lock;
  58        struct list_head dependents;
  59};
  60
  61struct acpi_power_resource_entry {
  62        struct list_head node;
  63        struct acpi_power_resource *resource;
  64};
  65
  66static LIST_HEAD(acpi_power_resource_list);
  67static DEFINE_MUTEX(power_resource_list_lock);
  68
  69/* --------------------------------------------------------------------------
  70                             Power Resource Management
  71   -------------------------------------------------------------------------- */
  72
  73static inline
  74struct acpi_power_resource *to_power_resource(struct acpi_device *device)
  75{
  76        return container_of(device, struct acpi_power_resource, device);
  77}
  78
  79static struct acpi_power_resource *acpi_power_get_context(acpi_handle handle)
  80{
  81        struct acpi_device *device;
  82
  83        if (acpi_bus_get_device(handle, &device))
  84                return NULL;
  85
  86        return to_power_resource(device);
  87}
  88
  89static int acpi_power_resources_list_add(acpi_handle handle,
  90                                         struct list_head *list)
  91{
  92        struct acpi_power_resource *resource = acpi_power_get_context(handle);
  93        struct acpi_power_resource_entry *entry;
  94
  95        if (!resource || !list)
  96                return -EINVAL;
  97
  98        entry = kzalloc(sizeof(*entry), GFP_KERNEL);
  99        if (!entry)
 100                return -ENOMEM;
 101
 102        entry->resource = resource;
 103        if (!list_empty(list)) {
 104                struct acpi_power_resource_entry *e;
 105
 106                list_for_each_entry(e, list, node)
 107                        if (e->resource->order > resource->order) {
 108                                list_add_tail(&entry->node, &e->node);
 109                                return 0;
 110                        }
 111        }
 112        list_add_tail(&entry->node, list);
 113        return 0;
 114}
 115
 116void acpi_power_resources_list_free(struct list_head *list)
 117{
 118        struct acpi_power_resource_entry *entry, *e;
 119
 120        list_for_each_entry_safe(entry, e, list, node) {
 121                list_del(&entry->node);
 122                kfree(entry);
 123        }
 124}
 125
 126static bool acpi_power_resource_is_dup(union acpi_object *package,
 127                                       unsigned int start, unsigned int i)
 128{
 129        acpi_handle rhandle, dup;
 130        unsigned int j;
 131
 132        /* The caller is expected to check the package element types */
 133        rhandle = package->package.elements[i].reference.handle;
 134        for (j = start; j < i; j++) {
 135                dup = package->package.elements[j].reference.handle;
 136                if (dup == rhandle)
 137                        return true;
 138        }
 139
 140        return false;
 141}
 142
 143int acpi_extract_power_resources(union acpi_object *package, unsigned int start,
 144                                 struct list_head *list)
 145{
 146        unsigned int i;
 147        int err = 0;
 148
 149        for (i = start; i < package->package.count; i++) {
 150                union acpi_object *element = &package->package.elements[i];
 151                struct acpi_device *rdev;
 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                rdev = acpi_add_power_resource(rhandle);
 169                if (!rdev) {
 170                        err = -ENODEV;
 171                        break;
 172                }
 173                err = acpi_power_resources_list_add(rhandle, list);
 174                if (err)
 175                        break;
 176
 177                to_power_resource(rdev)->users++;
 178        }
 179        if (err)
 180                acpi_power_resources_list_free(list);
 181
 182        return err;
 183}
 184
 185static int acpi_power_get_state(acpi_handle handle, int *state)
 186{
 187        acpi_status status = AE_OK;
 188        unsigned long long sta = 0;
 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_handle_debug(handle, "Power resource is %s\n",
 201                          *state ? "on" : "off");
 202
 203        return 0;
 204}
 205
 206static int acpi_power_get_list_state(struct list_head *list, int *state)
 207{
 208        struct acpi_power_resource_entry *entry;
 209        int cur_state;
 210
 211        if (!list || !state)
 212                return -EINVAL;
 213
 214        /* The state of the list is 'on' IFF all resources are 'on'. */
 215        cur_state = 0;
 216        list_for_each_entry(entry, list, node) {
 217                struct acpi_power_resource *resource = entry->resource;
 218                acpi_handle handle = resource->device.handle;
 219                int result;
 220
 221                mutex_lock(&resource->resource_lock);
 222                result = acpi_power_get_state(handle, &cur_state);
 223                mutex_unlock(&resource->resource_lock);
 224                if (result)
 225                        return result;
 226
 227                if (cur_state != ACPI_POWER_RESOURCE_STATE_ON)
 228                        break;
 229        }
 230
 231        pr_debug("Power resource list is %s\n", cur_state ? "on" : "off");
 232
 233        *state = cur_state;
 234        return 0;
 235}
 236
 237static int
 238acpi_power_resource_add_dependent(struct acpi_power_resource *resource,
 239                                  struct device *dev)
 240{
 241        struct acpi_power_dependent_device *dep;
 242        int ret = 0;
 243
 244        mutex_lock(&resource->resource_lock);
 245        list_for_each_entry(dep, &resource->dependents, node) {
 246                /* Only add it once */
 247                if (dep->dev == dev)
 248                        goto unlock;
 249        }
 250
 251        dep = kzalloc(sizeof(*dep), GFP_KERNEL);
 252        if (!dep) {
 253                ret = -ENOMEM;
 254                goto unlock;
 255        }
 256
 257        dep->dev = dev;
 258        list_add_tail(&dep->node, &resource->dependents);
 259        dev_dbg(dev, "added power dependency to [%s]\n", resource->name);
 260
 261unlock:
 262        mutex_unlock(&resource->resource_lock);
 263        return ret;
 264}
 265
 266static void
 267acpi_power_resource_remove_dependent(struct acpi_power_resource *resource,
 268                                     struct device *dev)
 269{
 270        struct acpi_power_dependent_device *dep;
 271
 272        mutex_lock(&resource->resource_lock);
 273        list_for_each_entry(dep, &resource->dependents, node) {
 274                if (dep->dev == dev) {
 275                        list_del(&dep->node);
 276                        kfree(dep);
 277                        dev_dbg(dev, "removed power dependency to [%s]\n",
 278                                resource->name);
 279                        break;
 280                }
 281        }
 282        mutex_unlock(&resource->resource_lock);
 283}
 284
 285/**
 286 * acpi_device_power_add_dependent - Add dependent device of this ACPI device
 287 * @adev: ACPI device pointer
 288 * @dev: Dependent device
 289 *
 290 * If @adev has non-empty _PR0 the @dev is added as dependent device to all
 291 * power resources returned by it. This means that whenever these power
 292 * resources are turned _ON the dependent devices get runtime resumed. This
 293 * is needed for devices such as PCI to allow its driver to re-initialize
 294 * it after it went to D0uninitialized.
 295 *
 296 * If @adev does not have _PR0 this does nothing.
 297 *
 298 * Returns %0 in case of success and negative errno otherwise.
 299 */
 300int acpi_device_power_add_dependent(struct acpi_device *adev,
 301                                    struct device *dev)
 302{
 303        struct acpi_power_resource_entry *entry;
 304        struct list_head *resources;
 305        int ret;
 306
 307        if (!adev->flags.power_manageable)
 308                return 0;
 309
 310        resources = &adev->power.states[ACPI_STATE_D0].resources;
 311        list_for_each_entry(entry, resources, node) {
 312                ret = acpi_power_resource_add_dependent(entry->resource, dev);
 313                if (ret)
 314                        goto err;
 315        }
 316
 317        return 0;
 318
 319err:
 320        list_for_each_entry(entry, resources, node)
 321                acpi_power_resource_remove_dependent(entry->resource, dev);
 322
 323        return ret;
 324}
 325
 326/**
 327 * acpi_device_power_remove_dependent - Remove dependent device
 328 * @adev: ACPI device pointer
 329 * @dev: Dependent device
 330 *
 331 * Does the opposite of acpi_device_power_add_dependent() and removes the
 332 * dependent device if it is found. Can be called to @adev that does not
 333 * have _PR0 as well.
 334 */
 335void acpi_device_power_remove_dependent(struct acpi_device *adev,
 336                                        struct device *dev)
 337{
 338        struct acpi_power_resource_entry *entry;
 339        struct list_head *resources;
 340
 341        if (!adev->flags.power_manageable)
 342                return;
 343
 344        resources = &adev->power.states[ACPI_STATE_D0].resources;
 345        list_for_each_entry_reverse(entry, resources, node)
 346                acpi_power_resource_remove_dependent(entry->resource, dev);
 347}
 348
 349static int __acpi_power_on(struct acpi_power_resource *resource)
 350{
 351        struct acpi_power_dependent_device *dep;
 352        acpi_status status = AE_OK;
 353
 354        status = acpi_evaluate_object(resource->device.handle, "_ON", NULL, NULL);
 355        if (ACPI_FAILURE(status))
 356                return -ENODEV;
 357
 358        pr_debug("Power resource [%s] turned on\n", resource->name);
 359
 360        /*
 361         * If there are other dependents on this power resource we need to
 362         * resume them now so that their drivers can re-initialize the
 363         * hardware properly after it went back to D0.
 364         */
 365        if (list_empty(&resource->dependents) ||
 366            list_is_singular(&resource->dependents))
 367                return 0;
 368
 369        list_for_each_entry(dep, &resource->dependents, node) {
 370                dev_dbg(dep->dev, "runtime resuming because [%s] turned on\n",
 371                        resource->name);
 372                pm_request_resume(dep->dev);
 373        }
 374
 375        return 0;
 376}
 377
 378static int acpi_power_on_unlocked(struct acpi_power_resource *resource)
 379{
 380        int result = 0;
 381
 382        if (resource->ref_count++) {
 383                pr_debug("Power resource [%s] already on\n", resource->name);
 384        } else {
 385                result = __acpi_power_on(resource);
 386                if (result)
 387                        resource->ref_count--;
 388        }
 389        return result;
 390}
 391
 392static int acpi_power_on(struct acpi_power_resource *resource)
 393{
 394        int result;
 395
 396        mutex_lock(&resource->resource_lock);
 397        result = acpi_power_on_unlocked(resource);
 398        mutex_unlock(&resource->resource_lock);
 399        return result;
 400}
 401
 402static int __acpi_power_off(struct acpi_power_resource *resource)
 403{
 404        acpi_status status;
 405
 406        status = acpi_evaluate_object(resource->device.handle, "_OFF",
 407                                      NULL, NULL);
 408        if (ACPI_FAILURE(status))
 409                return -ENODEV;
 410
 411        pr_debug("Power resource [%s] turned off\n", resource->name);
 412
 413        return 0;
 414}
 415
 416static int acpi_power_off_unlocked(struct acpi_power_resource *resource)
 417{
 418        int result = 0;
 419
 420        if (!resource->ref_count) {
 421                pr_debug("Power resource [%s] already off\n", resource->name);
 422                return 0;
 423        }
 424
 425        if (--resource->ref_count) {
 426                pr_debug("Power resource [%s] still in use\n", resource->name);
 427        } else {
 428                result = __acpi_power_off(resource);
 429                if (result)
 430                        resource->ref_count++;
 431        }
 432        return result;
 433}
 434
 435static int acpi_power_off(struct acpi_power_resource *resource)
 436{
 437        int result;
 438
 439        mutex_lock(&resource->resource_lock);
 440        result = acpi_power_off_unlocked(resource);
 441        mutex_unlock(&resource->resource_lock);
 442        return result;
 443}
 444
 445static int acpi_power_off_list(struct list_head *list)
 446{
 447        struct acpi_power_resource_entry *entry;
 448        int result = 0;
 449
 450        list_for_each_entry_reverse(entry, list, node) {
 451                result = acpi_power_off(entry->resource);
 452                if (result)
 453                        goto err;
 454        }
 455        return 0;
 456
 457 err:
 458        list_for_each_entry_continue(entry, list, node)
 459                acpi_power_on(entry->resource);
 460
 461        return result;
 462}
 463
 464static int acpi_power_on_list(struct list_head *list)
 465{
 466        struct acpi_power_resource_entry *entry;
 467        int result = 0;
 468
 469        list_for_each_entry(entry, list, node) {
 470                result = acpi_power_on(entry->resource);
 471                if (result)
 472                        goto err;
 473        }
 474        return 0;
 475
 476 err:
 477        list_for_each_entry_continue_reverse(entry, list, node)
 478                acpi_power_off(entry->resource);
 479
 480        return result;
 481}
 482
 483static struct attribute *attrs[] = {
 484        NULL,
 485};
 486
 487static const struct attribute_group attr_groups[] = {
 488        [ACPI_STATE_D0] = {
 489                .name = "power_resources_D0",
 490                .attrs = attrs,
 491        },
 492        [ACPI_STATE_D1] = {
 493                .name = "power_resources_D1",
 494                .attrs = attrs,
 495        },
 496        [ACPI_STATE_D2] = {
 497                .name = "power_resources_D2",
 498                .attrs = attrs,
 499        },
 500        [ACPI_STATE_D3_HOT] = {
 501                .name = "power_resources_D3hot",
 502                .attrs = attrs,
 503        },
 504};
 505
 506static const struct attribute_group wakeup_attr_group = {
 507        .name = "power_resources_wakeup",
 508        .attrs = attrs,
 509};
 510
 511static void acpi_power_hide_list(struct acpi_device *adev,
 512                                 struct list_head *resources,
 513                                 const struct attribute_group *attr_group)
 514{
 515        struct acpi_power_resource_entry *entry;
 516
 517        if (list_empty(resources))
 518                return;
 519
 520        list_for_each_entry_reverse(entry, resources, node) {
 521                struct acpi_device *res_dev = &entry->resource->device;
 522
 523                sysfs_remove_link_from_group(&adev->dev.kobj,
 524                                             attr_group->name,
 525                                             dev_name(&res_dev->dev));
 526        }
 527        sysfs_remove_group(&adev->dev.kobj, attr_group);
 528}
 529
 530static void acpi_power_expose_list(struct acpi_device *adev,
 531                                   struct list_head *resources,
 532                                   const struct attribute_group *attr_group)
 533{
 534        struct acpi_power_resource_entry *entry;
 535        int ret;
 536
 537        if (list_empty(resources))
 538                return;
 539
 540        ret = sysfs_create_group(&adev->dev.kobj, attr_group);
 541        if (ret)
 542                return;
 543
 544        list_for_each_entry(entry, resources, node) {
 545                struct acpi_device *res_dev = &entry->resource->device;
 546
 547                ret = sysfs_add_link_to_group(&adev->dev.kobj,
 548                                              attr_group->name,
 549                                              &res_dev->dev.kobj,
 550                                              dev_name(&res_dev->dev));
 551                if (ret) {
 552                        acpi_power_hide_list(adev, resources, attr_group);
 553                        break;
 554                }
 555        }
 556}
 557
 558static void acpi_power_expose_hide(struct acpi_device *adev,
 559                                   struct list_head *resources,
 560                                   const struct attribute_group *attr_group,
 561                                   bool expose)
 562{
 563        if (expose)
 564                acpi_power_expose_list(adev, resources, attr_group);
 565        else
 566                acpi_power_hide_list(adev, resources, attr_group);
 567}
 568
 569void acpi_power_add_remove_device(struct acpi_device *adev, bool add)
 570{
 571        int state;
 572
 573        if (adev->wakeup.flags.valid)
 574                acpi_power_expose_hide(adev, &adev->wakeup.resources,
 575                                       &wakeup_attr_group, add);
 576
 577        if (!adev->power.flags.power_resources)
 578                return;
 579
 580        for (state = ACPI_STATE_D0; state <= ACPI_STATE_D3_HOT; state++)
 581                acpi_power_expose_hide(adev,
 582                                       &adev->power.states[state].resources,
 583                                       &attr_groups[state], add);
 584}
 585
 586int acpi_power_wakeup_list_init(struct list_head *list, int *system_level_p)
 587{
 588        struct acpi_power_resource_entry *entry;
 589        int system_level = 5;
 590
 591        list_for_each_entry(entry, list, node) {
 592                struct acpi_power_resource *resource = entry->resource;
 593                acpi_handle handle = resource->device.handle;
 594                int result;
 595                int state;
 596
 597                mutex_lock(&resource->resource_lock);
 598
 599                result = acpi_power_get_state(handle, &state);
 600                if (result) {
 601                        mutex_unlock(&resource->resource_lock);
 602                        return result;
 603                }
 604                if (state == ACPI_POWER_RESOURCE_STATE_ON) {
 605                        resource->ref_count++;
 606                        resource->wakeup_enabled = true;
 607                }
 608                if (system_level > resource->system_level)
 609                        system_level = resource->system_level;
 610
 611                mutex_unlock(&resource->resource_lock);
 612        }
 613        *system_level_p = system_level;
 614        return 0;
 615}
 616
 617/* --------------------------------------------------------------------------
 618                             Device Power Management
 619   -------------------------------------------------------------------------- */
 620
 621/**
 622 * acpi_device_sleep_wake - execute _DSW (Device Sleep Wake) or (deprecated in
 623 *                          ACPI 3.0) _PSW (Power State Wake)
 624 * @dev: Device to handle.
 625 * @enable: 0 - disable, 1 - enable the wake capabilities of the device.
 626 * @sleep_state: Target sleep state of the system.
 627 * @dev_state: Target power state of the device.
 628 *
 629 * Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
 630 * State Wake) for the device, if present.  On failure reset the device's
 631 * wakeup.flags.valid flag.
 632 *
 633 * RETURN VALUE:
 634 * 0 if either _DSW or _PSW has been successfully executed
 635 * 0 if neither _DSW nor _PSW has been found
 636 * -ENODEV if the execution of either _DSW or _PSW has failed
 637 */
 638int acpi_device_sleep_wake(struct acpi_device *dev,
 639                           int enable, int sleep_state, int dev_state)
 640{
 641        union acpi_object in_arg[3];
 642        struct acpi_object_list arg_list = { 3, in_arg };
 643        acpi_status status = AE_OK;
 644
 645        /*
 646         * Try to execute _DSW first.
 647         *
 648         * Three arguments are needed for the _DSW object:
 649         * Argument 0: enable/disable the wake capabilities
 650         * Argument 1: target system state
 651         * Argument 2: target device state
 652         * When _DSW object is called to disable the wake capabilities, maybe
 653         * the first argument is filled. The values of the other two arguments
 654         * are meaningless.
 655         */
 656        in_arg[0].type = ACPI_TYPE_INTEGER;
 657        in_arg[0].integer.value = enable;
 658        in_arg[1].type = ACPI_TYPE_INTEGER;
 659        in_arg[1].integer.value = sleep_state;
 660        in_arg[2].type = ACPI_TYPE_INTEGER;
 661        in_arg[2].integer.value = dev_state;
 662        status = acpi_evaluate_object(dev->handle, "_DSW", &arg_list, NULL);
 663        if (ACPI_SUCCESS(status)) {
 664                return 0;
 665        } else if (status != AE_NOT_FOUND) {
 666                acpi_handle_info(dev->handle, "_DSW execution failed\n");
 667                dev->wakeup.flags.valid = 0;
 668                return -ENODEV;
 669        }
 670
 671        /* Execute _PSW */
 672        status = acpi_execute_simple_method(dev->handle, "_PSW", enable);
 673        if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {
 674                acpi_handle_info(dev->handle, "_PSW execution failed\n");
 675                dev->wakeup.flags.valid = 0;
 676                return -ENODEV;
 677        }
 678
 679        return 0;
 680}
 681
 682/*
 683 * Prepare a wakeup device, two steps (Ref ACPI 2.0:P229):
 684 * 1. Power on the power resources required for the wakeup device
 685 * 2. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
 686 *    State Wake) for the device, if present
 687 */
 688int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state)
 689{
 690        struct acpi_power_resource_entry *entry;
 691        int err = 0;
 692
 693        if (!dev || !dev->wakeup.flags.valid)
 694                return -EINVAL;
 695
 696        mutex_lock(&acpi_device_lock);
 697
 698        if (dev->wakeup.prepare_count++)
 699                goto out;
 700
 701        list_for_each_entry(entry, &dev->wakeup.resources, node) {
 702                struct acpi_power_resource *resource = entry->resource;
 703
 704                mutex_lock(&resource->resource_lock);
 705
 706                if (!resource->wakeup_enabled) {
 707                        err = acpi_power_on_unlocked(resource);
 708                        if (!err)
 709                                resource->wakeup_enabled = true;
 710                }
 711
 712                mutex_unlock(&resource->resource_lock);
 713
 714                if (err) {
 715                        dev_err(&dev->dev,
 716                                "Cannot turn wakeup power resources on\n");
 717                        dev->wakeup.flags.valid = 0;
 718                        goto out;
 719                }
 720        }
 721        /*
 722         * Passing 3 as the third argument below means the device may be
 723         * put into arbitrary power state afterward.
 724         */
 725        err = acpi_device_sleep_wake(dev, 1, sleep_state, 3);
 726        if (err)
 727                dev->wakeup.prepare_count = 0;
 728
 729 out:
 730        mutex_unlock(&acpi_device_lock);
 731        return err;
 732}
 733
 734/*
 735 * Shutdown a wakeup device, counterpart of above method
 736 * 1. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
 737 *    State Wake) for the device, if present
 738 * 2. Shutdown down the power resources
 739 */
 740int acpi_disable_wakeup_device_power(struct acpi_device *dev)
 741{
 742        struct acpi_power_resource_entry *entry;
 743        int err = 0;
 744
 745        if (!dev || !dev->wakeup.flags.valid)
 746                return -EINVAL;
 747
 748        mutex_lock(&acpi_device_lock);
 749
 750        if (--dev->wakeup.prepare_count > 0)
 751                goto out;
 752
 753        /*
 754         * Executing the code below even if prepare_count is already zero when
 755         * the function is called may be useful, for example for initialisation.
 756         */
 757        if (dev->wakeup.prepare_count < 0)
 758                dev->wakeup.prepare_count = 0;
 759
 760        err = acpi_device_sleep_wake(dev, 0, 0, 0);
 761        if (err)
 762                goto out;
 763
 764        list_for_each_entry(entry, &dev->wakeup.resources, node) {
 765                struct acpi_power_resource *resource = entry->resource;
 766
 767                mutex_lock(&resource->resource_lock);
 768
 769                if (resource->wakeup_enabled) {
 770                        err = acpi_power_off_unlocked(resource);
 771                        if (!err)
 772                                resource->wakeup_enabled = false;
 773                }
 774
 775                mutex_unlock(&resource->resource_lock);
 776
 777                if (err) {
 778                        dev_err(&dev->dev,
 779                                "Cannot turn wakeup power resources off\n");
 780                        dev->wakeup.flags.valid = 0;
 781                        break;
 782                }
 783        }
 784
 785 out:
 786        mutex_unlock(&acpi_device_lock);
 787        return err;
 788}
 789
 790int acpi_power_get_inferred_state(struct acpi_device *device, int *state)
 791{
 792        int result = 0;
 793        int list_state = 0;
 794        int i = 0;
 795
 796        if (!device || !state)
 797                return -EINVAL;
 798
 799        /*
 800         * We know a device's inferred power state when all the resources
 801         * required for a given D-state are 'on'.
 802         */
 803        for (i = ACPI_STATE_D0; i <= ACPI_STATE_D3_HOT; i++) {
 804                struct list_head *list = &device->power.states[i].resources;
 805
 806                if (list_empty(list))
 807                        continue;
 808
 809                result = acpi_power_get_list_state(list, &list_state);
 810                if (result)
 811                        return result;
 812
 813                if (list_state == ACPI_POWER_RESOURCE_STATE_ON) {
 814                        *state = i;
 815                        return 0;
 816                }
 817        }
 818
 819        *state = device->power.states[ACPI_STATE_D3_COLD].flags.valid ?
 820                ACPI_STATE_D3_COLD : ACPI_STATE_D3_HOT;
 821        return 0;
 822}
 823
 824int acpi_power_on_resources(struct acpi_device *device, int state)
 825{
 826        if (!device || state < ACPI_STATE_D0 || state > ACPI_STATE_D3_HOT)
 827                return -EINVAL;
 828
 829        return acpi_power_on_list(&device->power.states[state].resources);
 830}
 831
 832int acpi_power_transition(struct acpi_device *device, int state)
 833{
 834        int result = 0;
 835
 836        if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD))
 837                return -EINVAL;
 838
 839        if (device->power.state == state || !device->flags.power_manageable)
 840                return 0;
 841
 842        if ((device->power.state < ACPI_STATE_D0)
 843            || (device->power.state > ACPI_STATE_D3_COLD))
 844                return -ENODEV;
 845
 846        /*
 847         * First we reference all power resources required in the target list
 848         * (e.g. so the device doesn't lose power while transitioning).  Then,
 849         * we dereference all power resources used in the current list.
 850         */
 851        if (state < ACPI_STATE_D3_COLD)
 852                result = acpi_power_on_list(
 853                        &device->power.states[state].resources);
 854
 855        if (!result && device->power.state < ACPI_STATE_D3_COLD)
 856                acpi_power_off_list(
 857                        &device->power.states[device->power.state].resources);
 858
 859        /* We shouldn't change the state unless the above operations succeed. */
 860        device->power.state = result ? ACPI_STATE_UNKNOWN : state;
 861
 862        return result;
 863}
 864
 865static void acpi_release_power_resource(struct device *dev)
 866{
 867        struct acpi_device *device = to_acpi_device(dev);
 868        struct acpi_power_resource *resource;
 869
 870        resource = container_of(device, struct acpi_power_resource, device);
 871
 872        mutex_lock(&power_resource_list_lock);
 873        list_del(&resource->list_node);
 874        mutex_unlock(&power_resource_list_lock);
 875
 876        acpi_free_pnp_ids(&device->pnp);
 877        kfree(resource);
 878}
 879
 880static ssize_t resource_in_use_show(struct device *dev,
 881                                    struct device_attribute *attr,
 882                                    char *buf)
 883{
 884        struct acpi_power_resource *resource;
 885
 886        resource = to_power_resource(to_acpi_device(dev));
 887        return sprintf(buf, "%u\n", !!resource->ref_count);
 888}
 889static DEVICE_ATTR_RO(resource_in_use);
 890
 891static void acpi_power_sysfs_remove(struct acpi_device *device)
 892{
 893        device_remove_file(&device->dev, &dev_attr_resource_in_use);
 894}
 895
 896static void acpi_power_add_resource_to_list(struct acpi_power_resource *resource)
 897{
 898        mutex_lock(&power_resource_list_lock);
 899
 900        if (!list_empty(&acpi_power_resource_list)) {
 901                struct acpi_power_resource *r;
 902
 903                list_for_each_entry(r, &acpi_power_resource_list, list_node)
 904                        if (r->order > resource->order) {
 905                                list_add_tail(&resource->list_node, &r->list_node);
 906                                goto out;
 907                        }
 908        }
 909        list_add_tail(&resource->list_node, &acpi_power_resource_list);
 910
 911 out:
 912        mutex_unlock(&power_resource_list_lock);
 913}
 914
 915struct acpi_device *acpi_add_power_resource(acpi_handle handle)
 916{
 917        struct acpi_power_resource *resource;
 918        struct acpi_device *device = NULL;
 919        union acpi_object acpi_object;
 920        struct acpi_buffer buffer = { sizeof(acpi_object), &acpi_object };
 921        acpi_status status;
 922        int state, result = -ENODEV;
 923
 924        acpi_bus_get_device(handle, &device);
 925        if (device)
 926                return device;
 927
 928        resource = kzalloc(sizeof(*resource), GFP_KERNEL);
 929        if (!resource)
 930                return NULL;
 931
 932        device = &resource->device;
 933        acpi_init_device_object(device, handle, ACPI_BUS_TYPE_POWER);
 934        mutex_init(&resource->resource_lock);
 935        INIT_LIST_HEAD(&resource->list_node);
 936        INIT_LIST_HEAD(&resource->dependents);
 937        resource->name = device->pnp.bus_id;
 938        strcpy(acpi_device_name(device), ACPI_POWER_DEVICE_NAME);
 939        strcpy(acpi_device_class(device), ACPI_POWER_CLASS);
 940        device->power.state = ACPI_STATE_UNKNOWN;
 941
 942        /* Evaluate the object to get the system level and resource order. */
 943        status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
 944        if (ACPI_FAILURE(status))
 945                goto err;
 946
 947        resource->system_level = acpi_object.power_resource.system_level;
 948        resource->order = acpi_object.power_resource.resource_order;
 949
 950        result = acpi_power_get_state(handle, &state);
 951        if (result)
 952                goto err;
 953
 954        pr_info("%s [%s] (%s)\n", acpi_device_name(device),
 955                acpi_device_bid(device), state ? "on" : "off");
 956
 957        device->flags.match_driver = true;
 958        result = acpi_device_add(device, acpi_release_power_resource);
 959        if (result)
 960                goto err;
 961
 962        if (!device_create_file(&device->dev, &dev_attr_resource_in_use))
 963                device->remove = acpi_power_sysfs_remove;
 964
 965        acpi_power_add_resource_to_list(resource);
 966        acpi_device_add_finalize(device);
 967        return device;
 968
 969 err:
 970        acpi_release_power_resource(&device->dev);
 971        return NULL;
 972}
 973
 974#ifdef CONFIG_ACPI_SLEEP
 975void acpi_resume_power_resources(void)
 976{
 977        struct acpi_power_resource *resource;
 978
 979        mutex_lock(&power_resource_list_lock);
 980
 981        list_for_each_entry(resource, &acpi_power_resource_list, list_node) {
 982                int result, state;
 983
 984                mutex_lock(&resource->resource_lock);
 985
 986                result = acpi_power_get_state(resource->device.handle, &state);
 987                if (result) {
 988                        mutex_unlock(&resource->resource_lock);
 989                        continue;
 990                }
 991
 992                if (state == ACPI_POWER_RESOURCE_STATE_OFF
 993                    && resource->ref_count) {
 994                        dev_info(&resource->device.dev, "Turning ON\n");
 995                        __acpi_power_on(resource);
 996                }
 997
 998                mutex_unlock(&resource->resource_lock);
 999        }
1000
1001        mutex_unlock(&power_resource_list_lock);
1002}
1003#endif
1004
1005static void acpi_power_turn_off_if_unused(struct acpi_power_resource *resource,
1006                                       bool init)
1007{
1008        if (resource->ref_count > 0)
1009                return;
1010
1011        if (init) {
1012                if (resource->users > 0)
1013                        return;
1014        } else {
1015                int result, state;
1016
1017                result = acpi_power_get_state(resource->device.handle, &state);
1018                if (result || state == ACPI_POWER_RESOURCE_STATE_OFF)
1019                        return;
1020        }
1021
1022        dev_info(&resource->device.dev, "Turning OFF\n");
1023        __acpi_power_off(resource);
1024}
1025
1026/**
1027 * acpi_turn_off_unused_power_resources - Turn off power resources not in use.
1028 * @init: Control switch.
1029 *
1030 * If @ainit is set, unconditionally turn off all of the ACPI power resources
1031 * without any users.
1032 *
1033 * Otherwise, turn off all ACPI power resources without active references (that
1034 * is, the ones that should be "off" at the moment) that are "on".
1035 */
1036void acpi_turn_off_unused_power_resources(bool init)
1037{
1038        struct acpi_power_resource *resource;
1039
1040        mutex_lock(&power_resource_list_lock);
1041
1042        list_for_each_entry_reverse(resource, &acpi_power_resource_list, list_node) {
1043                mutex_lock(&resource->resource_lock);
1044
1045                acpi_power_turn_off_if_unused(resource, init);
1046
1047                mutex_unlock(&resource->resource_lock);
1048        }
1049
1050        mutex_unlock(&power_resource_list_lock);
1051}
1052