linux/drivers/acpi/power.c
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   1/*
   2 *  acpi_power.c - ACPI Bus Power Management ($Revision: 39 $)
   3 *
   4 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   5 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   6 *
   7 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   8 *
   9 *  This program is free software; you can redistribute it and/or modify
  10 *  it under the terms of the GNU General Public License as published by
  11 *  the Free Software Foundation; either version 2 of the License, or (at
  12 *  your option) any later version.
  13 *
  14 *  This program is distributed in the hope that it will be useful, but
  15 *  WITHOUT ANY WARRANTY; without even the implied warranty of
  16 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17 *  General Public License for more details.
  18 *
  19 *  You should have received a copy of the GNU General Public License along
  20 *  with this program; if not, write to the Free Software Foundation, Inc.,
  21 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  22 *
  23 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  24 */
  25
  26/*
  27 * ACPI power-managed devices may be controlled in two ways:
  28 * 1. via "Device Specific (D-State) Control"
  29 * 2. via "Power Resource Control".
  30 * This module is used to manage devices relying on Power Resource Control.
  31 * 
  32 * An ACPI "power resource object" describes a software controllable power
  33 * plane, clock plane, or other resource used by a power managed device.
  34 * A device may rely on multiple power resources, and a power resource
  35 * may be shared by multiple devices.
  36 */
  37
  38#include <linux/kernel.h>
  39#include <linux/module.h>
  40#include <linux/init.h>
  41#include <linux/types.h>
  42#include <linux/slab.h>
  43#include <linux/pm_runtime.h>
  44#include <linux/sysfs.h>
  45#include <acpi/acpi_bus.h>
  46#include <acpi/acpi_drivers.h>
  47#include "sleep.h"
  48#include "internal.h"
  49
  50#define PREFIX "ACPI: "
  51
  52#define _COMPONENT                      ACPI_POWER_COMPONENT
  53ACPI_MODULE_NAME("power");
  54#define ACPI_POWER_CLASS                "power_resource"
  55#define ACPI_POWER_DEVICE_NAME          "Power Resource"
  56#define ACPI_POWER_FILE_INFO            "info"
  57#define ACPI_POWER_FILE_STATUS          "state"
  58#define ACPI_POWER_RESOURCE_STATE_OFF   0x00
  59#define ACPI_POWER_RESOURCE_STATE_ON    0x01
  60#define ACPI_POWER_RESOURCE_STATE_UNKNOWN 0xFF
  61
  62struct acpi_power_dependent_device {
  63        struct list_head node;
  64        struct acpi_device *adev;
  65        struct work_struct work;
  66};
  67
  68struct acpi_power_resource {
  69        struct acpi_device device;
  70        struct list_head list_node;
  71        struct list_head dependent;
  72        char *name;
  73        u32 system_level;
  74        u32 order;
  75        unsigned int ref_count;
  76        bool wakeup_enabled;
  77        struct mutex resource_lock;
  78};
  79
  80struct acpi_power_resource_entry {
  81        struct list_head node;
  82        struct acpi_power_resource *resource;
  83};
  84
  85static LIST_HEAD(acpi_power_resource_list);
  86static DEFINE_MUTEX(power_resource_list_lock);
  87
  88/* --------------------------------------------------------------------------
  89                             Power Resource Management
  90   -------------------------------------------------------------------------- */
  91
  92static inline
  93struct acpi_power_resource *to_power_resource(struct acpi_device *device)
  94{
  95        return container_of(device, struct acpi_power_resource, device);
  96}
  97
  98static struct acpi_power_resource *acpi_power_get_context(acpi_handle handle)
  99{
 100        struct acpi_device *device;
 101
 102        if (acpi_bus_get_device(handle, &device))
 103                return NULL;
 104
 105        return to_power_resource(device);
 106}
 107
 108static int acpi_power_resources_list_add(acpi_handle handle,
 109                                         struct list_head *list)
 110{
 111        struct acpi_power_resource *resource = acpi_power_get_context(handle);
 112        struct acpi_power_resource_entry *entry;
 113
 114        if (!resource || !list)
 115                return -EINVAL;
 116
 117        entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 118        if (!entry)
 119                return -ENOMEM;
 120
 121        entry->resource = resource;
 122        if (!list_empty(list)) {
 123                struct acpi_power_resource_entry *e;
 124
 125                list_for_each_entry(e, list, node)
 126                        if (e->resource->order > resource->order) {
 127                                list_add_tail(&entry->node, &e->node);
 128                                return 0;
 129                        }
 130        }
 131        list_add_tail(&entry->node, list);
 132        return 0;
 133}
 134
 135void acpi_power_resources_list_free(struct list_head *list)
 136{
 137        struct acpi_power_resource_entry *entry, *e;
 138
 139        list_for_each_entry_safe(entry, e, list, node) {
 140                list_del(&entry->node);
 141                kfree(entry);
 142        }
 143}
 144
 145int acpi_extract_power_resources(union acpi_object *package, unsigned int start,
 146                                 struct list_head *list)
 147{
 148        unsigned int i;
 149        int err = 0;
 150
 151        for (i = start; i < package->package.count; i++) {
 152                union acpi_object *element = &package->package.elements[i];
 153                acpi_handle rhandle;
 154
 155                if (element->type != ACPI_TYPE_LOCAL_REFERENCE) {
 156                        err = -ENODATA;
 157                        break;
 158                }
 159                rhandle = element->reference.handle;
 160                if (!rhandle) {
 161                        err = -ENODEV;
 162                        break;
 163                }
 164                err = acpi_add_power_resource(rhandle);
 165                if (err)
 166                        break;
 167
 168                err = acpi_power_resources_list_add(rhandle, list);
 169                if (err)
 170                        break;
 171        }
 172        if (err)
 173                acpi_power_resources_list_free(list);
 174
 175        return err;
 176}
 177
 178static int acpi_power_get_state(acpi_handle handle, int *state)
 179{
 180        acpi_status status = AE_OK;
 181        unsigned long long sta = 0;
 182        char node_name[5];
 183        struct acpi_buffer buffer = { sizeof(node_name), node_name };
 184
 185
 186        if (!handle || !state)
 187                return -EINVAL;
 188
 189        status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
 190        if (ACPI_FAILURE(status))
 191                return -ENODEV;
 192
 193        *state = (sta & 0x01)?ACPI_POWER_RESOURCE_STATE_ON:
 194                              ACPI_POWER_RESOURCE_STATE_OFF;
 195
 196        acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
 197
 198        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] is %s\n",
 199                          node_name,
 200                                *state ? "on" : "off"));
 201
 202        return 0;
 203}
 204
 205static int acpi_power_get_list_state(struct list_head *list, int *state)
 206{
 207        struct acpi_power_resource_entry *entry;
 208        int cur_state;
 209
 210        if (!list || !state)
 211                return -EINVAL;
 212
 213        /* The state of the list is 'on' IFF all resources are 'on'. */
 214        list_for_each_entry(entry, list, node) {
 215                struct acpi_power_resource *resource = entry->resource;
 216                acpi_handle handle = resource->device.handle;
 217                int result;
 218
 219                mutex_lock(&resource->resource_lock);
 220                result = acpi_power_get_state(handle, &cur_state);
 221                mutex_unlock(&resource->resource_lock);
 222                if (result)
 223                        return result;
 224
 225                if (cur_state != ACPI_POWER_RESOURCE_STATE_ON)
 226                        break;
 227        }
 228
 229        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource list is %s\n",
 230                          cur_state ? "on" : "off"));
 231
 232        *state = cur_state;
 233        return 0;
 234}
 235
 236static void acpi_power_resume_dependent(struct work_struct *work)
 237{
 238        struct acpi_power_dependent_device *dep;
 239        struct acpi_device_physical_node *pn;
 240        struct acpi_device *adev;
 241        int state;
 242
 243        dep = container_of(work, struct acpi_power_dependent_device, work);
 244        adev = dep->adev;
 245        if (acpi_power_get_inferred_state(adev, &state))
 246                return;
 247
 248        if (state > ACPI_STATE_D0)
 249                return;
 250
 251        mutex_lock(&adev->physical_node_lock);
 252
 253        list_for_each_entry(pn, &adev->physical_node_list, node)
 254                pm_request_resume(pn->dev);
 255
 256        list_for_each_entry(pn, &adev->power_dependent, node)
 257                pm_request_resume(pn->dev);
 258
 259        mutex_unlock(&adev->physical_node_lock);
 260}
 261
 262static int __acpi_power_on(struct acpi_power_resource *resource)
 263{
 264        acpi_status status = AE_OK;
 265
 266        status = acpi_evaluate_object(resource->device.handle, "_ON", NULL, NULL);
 267        if (ACPI_FAILURE(status))
 268                return -ENODEV;
 269
 270        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Power resource [%s] turned on\n",
 271                          resource->name));
 272
 273        return 0;
 274}
 275
 276static int acpi_power_on_unlocked(struct acpi_power_resource *resource)
 277{
 278        int result = 0;
 279
 280        if (resource->ref_count++) {
 281                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 282                                  "Power resource [%s] already on\n",
 283                                  resource->name));
 284        } else {
 285                result = __acpi_power_on(resource);
 286                if (result) {
 287                        resource->ref_count--;
 288                } else {
 289                        struct acpi_power_dependent_device *dep;
 290
 291                        list_for_each_entry(dep, &resource->dependent, node)
 292                                schedule_work(&dep->work);
 293                }
 294        }
 295        return result;
 296}
 297
 298static int acpi_power_on(struct acpi_power_resource *resource)
 299{
 300        int result;
 301
 302        mutex_lock(&resource->resource_lock);
 303        result = acpi_power_on_unlocked(resource);
 304        mutex_unlock(&resource->resource_lock);
 305        return result;
 306}
 307
 308static int __acpi_power_off(struct acpi_power_resource *resource)
 309{
 310        acpi_status status;
 311
 312        status = acpi_evaluate_object(resource->device.handle, "_OFF",
 313                                      NULL, NULL);
 314        if (ACPI_FAILURE(status))
 315                return -ENODEV;
 316
 317        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Power resource [%s] turned off\n",
 318                          resource->name));
 319        return 0;
 320}
 321
 322static int acpi_power_off_unlocked(struct acpi_power_resource *resource)
 323{
 324        int result = 0;
 325
 326        if (!resource->ref_count) {
 327                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 328                                  "Power resource [%s] already off\n",
 329                                  resource->name));
 330                return 0;
 331        }
 332
 333        if (--resource->ref_count) {
 334                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 335                                  "Power resource [%s] still in use\n",
 336                                  resource->name));
 337        } else {
 338                result = __acpi_power_off(resource);
 339                if (result)
 340                        resource->ref_count++;
 341        }
 342        return result;
 343}
 344
 345static int acpi_power_off(struct acpi_power_resource *resource)
 346{
 347        int result;
 348
 349        mutex_lock(&resource->resource_lock);
 350        result = acpi_power_off_unlocked(resource);
 351        mutex_unlock(&resource->resource_lock);
 352        return result;
 353}
 354
 355static int acpi_power_off_list(struct list_head *list)
 356{
 357        struct acpi_power_resource_entry *entry;
 358        int result = 0;
 359
 360        list_for_each_entry_reverse(entry, list, node) {
 361                result = acpi_power_off(entry->resource);
 362                if (result)
 363                        goto err;
 364        }
 365        return 0;
 366
 367 err:
 368        list_for_each_entry_continue(entry, list, node)
 369                acpi_power_on(entry->resource);
 370
 371        return result;
 372}
 373
 374static int acpi_power_on_list(struct list_head *list)
 375{
 376        struct acpi_power_resource_entry *entry;
 377        int result = 0;
 378
 379        list_for_each_entry(entry, list, node) {
 380                result = acpi_power_on(entry->resource);
 381                if (result)
 382                        goto err;
 383        }
 384        return 0;
 385
 386 err:
 387        list_for_each_entry_continue_reverse(entry, list, node)
 388                acpi_power_off(entry->resource);
 389
 390        return result;
 391}
 392
 393static void acpi_power_add_dependent(struct acpi_power_resource *resource,
 394                                     struct acpi_device *adev)
 395{
 396        struct acpi_power_dependent_device *dep;
 397
 398        mutex_lock(&resource->resource_lock);
 399
 400        list_for_each_entry(dep, &resource->dependent, node)
 401                if (dep->adev == adev)
 402                        goto out;
 403
 404        dep = kzalloc(sizeof(*dep), GFP_KERNEL);
 405        if (!dep)
 406                goto out;
 407
 408        dep->adev = adev;
 409        INIT_WORK(&dep->work, acpi_power_resume_dependent);
 410        list_add_tail(&dep->node, &resource->dependent);
 411
 412 out:
 413        mutex_unlock(&resource->resource_lock);
 414}
 415
 416static void acpi_power_remove_dependent(struct acpi_power_resource *resource,
 417                                        struct acpi_device *adev)
 418{
 419        struct acpi_power_dependent_device *dep;
 420        struct work_struct *work = NULL;
 421
 422        mutex_lock(&resource->resource_lock);
 423
 424        list_for_each_entry(dep, &resource->dependent, node)
 425                if (dep->adev == adev) {
 426                        list_del(&dep->node);
 427                        work = &dep->work;
 428                        break;
 429                }
 430
 431        mutex_unlock(&resource->resource_lock);
 432
 433        if (work) {
 434                cancel_work_sync(work);
 435                kfree(dep);
 436        }
 437}
 438
 439static struct attribute *attrs[] = {
 440        NULL,
 441};
 442
 443static struct attribute_group attr_groups[] = {
 444        [ACPI_STATE_D0] = {
 445                .name = "power_resources_D0",
 446                .attrs = attrs,
 447        },
 448        [ACPI_STATE_D1] = {
 449                .name = "power_resources_D1",
 450                .attrs = attrs,
 451        },
 452        [ACPI_STATE_D2] = {
 453                .name = "power_resources_D2",
 454                .attrs = attrs,
 455        },
 456        [ACPI_STATE_D3_HOT] = {
 457                .name = "power_resources_D3hot",
 458                .attrs = attrs,
 459        },
 460};
 461
 462static struct attribute_group wakeup_attr_group = {
 463        .name = "power_resources_wakeup",
 464        .attrs = attrs,
 465};
 466
 467static void acpi_power_hide_list(struct acpi_device *adev,
 468                                 struct list_head *resources,
 469                                 struct attribute_group *attr_group)
 470{
 471        struct acpi_power_resource_entry *entry;
 472
 473        if (list_empty(resources))
 474                return;
 475
 476        list_for_each_entry_reverse(entry, resources, node) {
 477                struct acpi_device *res_dev = &entry->resource->device;
 478
 479                sysfs_remove_link_from_group(&adev->dev.kobj,
 480                                             attr_group->name,
 481                                             dev_name(&res_dev->dev));
 482        }
 483        sysfs_remove_group(&adev->dev.kobj, attr_group);
 484}
 485
 486static void acpi_power_expose_list(struct acpi_device *adev,
 487                                   struct list_head *resources,
 488                                   struct attribute_group *attr_group)
 489{
 490        struct acpi_power_resource_entry *entry;
 491        int ret;
 492
 493        if (list_empty(resources))
 494                return;
 495
 496        ret = sysfs_create_group(&adev->dev.kobj, attr_group);
 497        if (ret)
 498                return;
 499
 500        list_for_each_entry(entry, resources, node) {
 501                struct acpi_device *res_dev = &entry->resource->device;
 502
 503                ret = sysfs_add_link_to_group(&adev->dev.kobj,
 504                                              attr_group->name,
 505                                              &res_dev->dev.kobj,
 506                                              dev_name(&res_dev->dev));
 507                if (ret) {
 508                        acpi_power_hide_list(adev, resources, attr_group);
 509                        break;
 510                }
 511        }
 512}
 513
 514static void acpi_power_expose_hide(struct acpi_device *adev,
 515                                   struct list_head *resources,
 516                                   struct attribute_group *attr_group,
 517                                   bool expose)
 518{
 519        if (expose)
 520                acpi_power_expose_list(adev, resources, attr_group);
 521        else
 522                acpi_power_hide_list(adev, resources, attr_group);
 523}
 524
 525void acpi_power_add_remove_device(struct acpi_device *adev, bool add)
 526{
 527        struct acpi_device_power_state *ps;
 528        struct acpi_power_resource_entry *entry;
 529        int state;
 530
 531        if (adev->wakeup.flags.valid)
 532                acpi_power_expose_hide(adev, &adev->wakeup.resources,
 533                                       &wakeup_attr_group, add);
 534
 535        if (!adev->power.flags.power_resources)
 536                return;
 537
 538        ps = &adev->power.states[ACPI_STATE_D0];
 539        list_for_each_entry(entry, &ps->resources, node) {
 540                struct acpi_power_resource *resource = entry->resource;
 541
 542                if (add)
 543                        acpi_power_add_dependent(resource, adev);
 544                else
 545                        acpi_power_remove_dependent(resource, adev);
 546        }
 547
 548        for (state = ACPI_STATE_D0; state <= ACPI_STATE_D3_HOT; state++)
 549                acpi_power_expose_hide(adev,
 550                                       &adev->power.states[state].resources,
 551                                       &attr_groups[state], add);
 552}
 553
 554int acpi_power_wakeup_list_init(struct list_head *list, int *system_level_p)
 555{
 556        struct acpi_power_resource_entry *entry;
 557        int system_level = 5;
 558
 559        list_for_each_entry(entry, list, node) {
 560                struct acpi_power_resource *resource = entry->resource;
 561                acpi_handle handle = resource->device.handle;
 562                int result;
 563                int state;
 564
 565                mutex_lock(&resource->resource_lock);
 566
 567                result = acpi_power_get_state(handle, &state);
 568                if (result) {
 569                        mutex_unlock(&resource->resource_lock);
 570                        return result;
 571                }
 572                if (state == ACPI_POWER_RESOURCE_STATE_ON) {
 573                        resource->ref_count++;
 574                        resource->wakeup_enabled = true;
 575                }
 576                if (system_level > resource->system_level)
 577                        system_level = resource->system_level;
 578
 579                mutex_unlock(&resource->resource_lock);
 580        }
 581        *system_level_p = system_level;
 582        return 0;
 583}
 584
 585/* --------------------------------------------------------------------------
 586                             Device Power Management
 587   -------------------------------------------------------------------------- */
 588
 589/**
 590 * acpi_device_sleep_wake - execute _DSW (Device Sleep Wake) or (deprecated in
 591 *                          ACPI 3.0) _PSW (Power State Wake)
 592 * @dev: Device to handle.
 593 * @enable: 0 - disable, 1 - enable the wake capabilities of the device.
 594 * @sleep_state: Target sleep state of the system.
 595 * @dev_state: Target power state of the device.
 596 *
 597 * Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
 598 * State Wake) for the device, if present.  On failure reset the device's
 599 * wakeup.flags.valid flag.
 600 *
 601 * RETURN VALUE:
 602 * 0 if either _DSW or _PSW has been successfully executed
 603 * 0 if neither _DSW nor _PSW has been found
 604 * -ENODEV if the execution of either _DSW or _PSW has failed
 605 */
 606int acpi_device_sleep_wake(struct acpi_device *dev,
 607                           int enable, int sleep_state, int dev_state)
 608{
 609        union acpi_object in_arg[3];
 610        struct acpi_object_list arg_list = { 3, in_arg };
 611        acpi_status status = AE_OK;
 612
 613        /*
 614         * Try to execute _DSW first.
 615         *
 616         * Three agruments are needed for the _DSW object:
 617         * Argument 0: enable/disable the wake capabilities
 618         * Argument 1: target system state
 619         * Argument 2: target device state
 620         * When _DSW object is called to disable the wake capabilities, maybe
 621         * the first argument is filled. The values of the other two agruments
 622         * are meaningless.
 623         */
 624        in_arg[0].type = ACPI_TYPE_INTEGER;
 625        in_arg[0].integer.value = enable;
 626        in_arg[1].type = ACPI_TYPE_INTEGER;
 627        in_arg[1].integer.value = sleep_state;
 628        in_arg[2].type = ACPI_TYPE_INTEGER;
 629        in_arg[2].integer.value = dev_state;
 630        status = acpi_evaluate_object(dev->handle, "_DSW", &arg_list, NULL);
 631        if (ACPI_SUCCESS(status)) {
 632                return 0;
 633        } else if (status != AE_NOT_FOUND) {
 634                printk(KERN_ERR PREFIX "_DSW execution failed\n");
 635                dev->wakeup.flags.valid = 0;
 636                return -ENODEV;
 637        }
 638
 639        /* Execute _PSW */
 640        arg_list.count = 1;
 641        in_arg[0].integer.value = enable;
 642        status = acpi_evaluate_object(dev->handle, "_PSW", &arg_list, NULL);
 643        if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {
 644                printk(KERN_ERR PREFIX "_PSW execution failed\n");
 645                dev->wakeup.flags.valid = 0;
 646                return -ENODEV;
 647        }
 648
 649        return 0;
 650}
 651
 652/*
 653 * Prepare a wakeup device, two steps (Ref ACPI 2.0:P229):
 654 * 1. Power on the power resources required for the wakeup device 
 655 * 2. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
 656 *    State Wake) for the device, if present
 657 */
 658int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state)
 659{
 660        struct acpi_power_resource_entry *entry;
 661        int err = 0;
 662
 663        if (!dev || !dev->wakeup.flags.valid)
 664                return -EINVAL;
 665
 666        mutex_lock(&acpi_device_lock);
 667
 668        if (dev->wakeup.prepare_count++)
 669                goto out;
 670
 671        list_for_each_entry(entry, &dev->wakeup.resources, node) {
 672                struct acpi_power_resource *resource = entry->resource;
 673
 674                mutex_lock(&resource->resource_lock);
 675
 676                if (!resource->wakeup_enabled) {
 677                        err = acpi_power_on_unlocked(resource);
 678                        if (!err)
 679                                resource->wakeup_enabled = true;
 680                }
 681
 682                mutex_unlock(&resource->resource_lock);
 683
 684                if (err) {
 685                        dev_err(&dev->dev,
 686                                "Cannot turn wakeup power resources on\n");
 687                        dev->wakeup.flags.valid = 0;
 688                        goto out;
 689                }
 690        }
 691        /*
 692         * Passing 3 as the third argument below means the device may be
 693         * put into arbitrary power state afterward.
 694         */
 695        err = acpi_device_sleep_wake(dev, 1, sleep_state, 3);
 696        if (err)
 697                dev->wakeup.prepare_count = 0;
 698
 699 out:
 700        mutex_unlock(&acpi_device_lock);
 701        return err;
 702}
 703
 704/*
 705 * Shutdown a wakeup device, counterpart of above method
 706 * 1. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
 707 *    State Wake) for the device, if present
 708 * 2. Shutdown down the power resources
 709 */
 710int acpi_disable_wakeup_device_power(struct acpi_device *dev)
 711{
 712        struct acpi_power_resource_entry *entry;
 713        int err = 0;
 714
 715        if (!dev || !dev->wakeup.flags.valid)
 716                return -EINVAL;
 717
 718        mutex_lock(&acpi_device_lock);
 719
 720        if (--dev->wakeup.prepare_count > 0)
 721                goto out;
 722
 723        /*
 724         * Executing the code below even if prepare_count is already zero when
 725         * the function is called may be useful, for example for initialisation.
 726         */
 727        if (dev->wakeup.prepare_count < 0)
 728                dev->wakeup.prepare_count = 0;
 729
 730        err = acpi_device_sleep_wake(dev, 0, 0, 0);
 731        if (err)
 732                goto out;
 733
 734        list_for_each_entry(entry, &dev->wakeup.resources, node) {
 735                struct acpi_power_resource *resource = entry->resource;
 736
 737                mutex_lock(&resource->resource_lock);
 738
 739                if (resource->wakeup_enabled) {
 740                        err = acpi_power_off_unlocked(resource);
 741                        if (!err)
 742                                resource->wakeup_enabled = false;
 743                }
 744
 745                mutex_unlock(&resource->resource_lock);
 746
 747                if (err) {
 748                        dev_err(&dev->dev,
 749                                "Cannot turn wakeup power resources off\n");
 750                        dev->wakeup.flags.valid = 0;
 751                        break;
 752                }
 753        }
 754
 755 out:
 756        mutex_unlock(&acpi_device_lock);
 757        return err;
 758}
 759
 760int acpi_power_get_inferred_state(struct acpi_device *device, int *state)
 761{
 762        int result = 0;
 763        int list_state = 0;
 764        int i = 0;
 765
 766        if (!device || !state)
 767                return -EINVAL;
 768
 769        /*
 770         * We know a device's inferred power state when all the resources
 771         * required for a given D-state are 'on'.
 772         */
 773        for (i = ACPI_STATE_D0; i <= ACPI_STATE_D3_HOT; i++) {
 774                struct list_head *list = &device->power.states[i].resources;
 775
 776                if (list_empty(list))
 777                        continue;
 778
 779                result = acpi_power_get_list_state(list, &list_state);
 780                if (result)
 781                        return result;
 782
 783                if (list_state == ACPI_POWER_RESOURCE_STATE_ON) {
 784                        *state = i;
 785                        return 0;
 786                }
 787        }
 788
 789        *state = ACPI_STATE_D3;
 790        return 0;
 791}
 792
 793int acpi_power_on_resources(struct acpi_device *device, int state)
 794{
 795        if (!device || state < ACPI_STATE_D0 || state > ACPI_STATE_D3_HOT)
 796                return -EINVAL;
 797
 798        return acpi_power_on_list(&device->power.states[state].resources);
 799}
 800
 801int acpi_power_transition(struct acpi_device *device, int state)
 802{
 803        int result = 0;
 804
 805        if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD))
 806                return -EINVAL;
 807
 808        if (device->power.state == state || !device->flags.power_manageable)
 809                return 0;
 810
 811        if ((device->power.state < ACPI_STATE_D0)
 812            || (device->power.state > ACPI_STATE_D3_COLD))
 813                return -ENODEV;
 814
 815        /* TBD: Resources must be ordered. */
 816
 817        /*
 818         * First we reference all power resources required in the target list
 819         * (e.g. so the device doesn't lose power while transitioning).  Then,
 820         * we dereference all power resources used in the current list.
 821         */
 822        if (state < ACPI_STATE_D3_COLD)
 823                result = acpi_power_on_list(
 824                        &device->power.states[state].resources);
 825
 826        if (!result && device->power.state < ACPI_STATE_D3_COLD)
 827                acpi_power_off_list(
 828                        &device->power.states[device->power.state].resources);
 829
 830        /* We shouldn't change the state unless the above operations succeed. */
 831        device->power.state = result ? ACPI_STATE_UNKNOWN : state;
 832
 833        return result;
 834}
 835
 836static void acpi_release_power_resource(struct device *dev)
 837{
 838        struct acpi_device *device = to_acpi_device(dev);
 839        struct acpi_power_resource *resource;
 840
 841        resource = container_of(device, struct acpi_power_resource, device);
 842
 843        mutex_lock(&power_resource_list_lock);
 844        list_del(&resource->list_node);
 845        mutex_unlock(&power_resource_list_lock);
 846
 847        acpi_free_pnp_ids(&device->pnp);
 848        kfree(resource);
 849}
 850
 851static ssize_t acpi_power_in_use_show(struct device *dev,
 852                                      struct device_attribute *attr,
 853                                      char *buf) {
 854        struct acpi_power_resource *resource;
 855
 856        resource = to_power_resource(to_acpi_device(dev));
 857        return sprintf(buf, "%u\n", !!resource->ref_count);
 858}
 859static DEVICE_ATTR(resource_in_use, 0444, acpi_power_in_use_show, NULL);
 860
 861static void acpi_power_sysfs_remove(struct acpi_device *device)
 862{
 863        device_remove_file(&device->dev, &dev_attr_resource_in_use);
 864}
 865
 866int acpi_add_power_resource(acpi_handle handle)
 867{
 868        struct acpi_power_resource *resource;
 869        struct acpi_device *device = NULL;
 870        union acpi_object acpi_object;
 871        struct acpi_buffer buffer = { sizeof(acpi_object), &acpi_object };
 872        acpi_status status;
 873        int state, result = -ENODEV;
 874
 875        acpi_bus_get_device(handle, &device);
 876        if (device)
 877                return 0;
 878
 879        resource = kzalloc(sizeof(*resource), GFP_KERNEL);
 880        if (!resource)
 881                return -ENOMEM;
 882
 883        device = &resource->device;
 884        acpi_init_device_object(device, handle, ACPI_BUS_TYPE_POWER,
 885                                ACPI_STA_DEFAULT);
 886        mutex_init(&resource->resource_lock);
 887        INIT_LIST_HEAD(&resource->dependent);
 888        INIT_LIST_HEAD(&resource->list_node);
 889        resource->name = device->pnp.bus_id;
 890        strcpy(acpi_device_name(device), ACPI_POWER_DEVICE_NAME);
 891        strcpy(acpi_device_class(device), ACPI_POWER_CLASS);
 892        device->power.state = ACPI_STATE_UNKNOWN;
 893
 894        /* Evalute the object to get the system level and resource order. */
 895        status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
 896        if (ACPI_FAILURE(status))
 897                goto err;
 898
 899        resource->system_level = acpi_object.power_resource.system_level;
 900        resource->order = acpi_object.power_resource.resource_order;
 901
 902        result = acpi_power_get_state(handle, &state);
 903        if (result)
 904                goto err;
 905
 906        printk(KERN_INFO PREFIX "%s [%s] (%s)\n", acpi_device_name(device),
 907               acpi_device_bid(device), state ? "on" : "off");
 908
 909        device->flags.match_driver = true;
 910        result = acpi_device_add(device, acpi_release_power_resource);
 911        if (result)
 912                goto err;
 913
 914        if (!device_create_file(&device->dev, &dev_attr_resource_in_use))
 915                device->remove = acpi_power_sysfs_remove;
 916
 917        mutex_lock(&power_resource_list_lock);
 918        list_add(&resource->list_node, &acpi_power_resource_list);
 919        mutex_unlock(&power_resource_list_lock);
 920        acpi_device_add_finalize(device);
 921        return 0;
 922
 923 err:
 924        acpi_release_power_resource(&device->dev);
 925        return result;
 926}
 927
 928#ifdef CONFIG_ACPI_SLEEP
 929void acpi_resume_power_resources(void)
 930{
 931        struct acpi_power_resource *resource;
 932
 933        mutex_lock(&power_resource_list_lock);
 934
 935        list_for_each_entry(resource, &acpi_power_resource_list, list_node) {
 936                int result, state;
 937
 938                mutex_lock(&resource->resource_lock);
 939
 940                result = acpi_power_get_state(resource->device.handle, &state);
 941                if (result)
 942                        continue;
 943
 944                if (state == ACPI_POWER_RESOURCE_STATE_OFF
 945                    && resource->ref_count) {
 946                        dev_info(&resource->device.dev, "Turning ON\n");
 947                        __acpi_power_on(resource);
 948                } else if (state == ACPI_POWER_RESOURCE_STATE_ON
 949                    && !resource->ref_count) {
 950                        dev_info(&resource->device.dev, "Turning OFF\n");
 951                        __acpi_power_off(resource);
 952                }
 953
 954                mutex_unlock(&resource->resource_lock);
 955        }
 956
 957        mutex_unlock(&power_resource_list_lock);
 958}
 959#endif
 960
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