drivers/acpi/power.c

   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 <acpi/acpi_bus.h>
  45 #include <acpi/acpi_drivers.h>
  46 #include "sleep.h"
  47 #include "internal.h"
  48
  49 #define PREFIX "ACPI: "
  50
  51 #define _COMPONENT                      ACPI_POWER_COMPONENT
  52 ACPI_MODULE_NAME("power");
  53 #define ACPI_POWER_CLASS                "power_resource"
  54 #define ACPI_POWER_DEVICE_NAME          "Power Resource"
  55 #define ACPI_POWER_FILE_INFO            "info"
  56 #define ACPI_POWER_FILE_STATUS          "state"
  57 #define ACPI_POWER_RESOURCE_STATE_OFF   0x00
  58 #define ACPI_POWER_RESOURCE_STATE_ON    0x01
  59 #define ACPI_POWER_RESOURCE_STATE_UNKNOWN 0xFF
  60
  61 static int acpi_power_add(struct acpi_device *device);
  62 static int acpi_power_remove(struct acpi_device *device, int type);
  63
  64 static const struct acpi_device_id power_device_ids[] = {
  65         {ACPI_POWER_HID, 0},
  66         {"", 0},
  67 };
  68 MODULE_DEVICE_TABLE(acpi, power_device_ids);
  69
  70 #ifdef CONFIG_PM_SLEEP
  71 static int acpi_power_resume(struct device *dev);
  72 #endif
  73 static SIMPLE_DEV_PM_OPS(acpi_power_pm, NULL, acpi_power_resume);
  74
  75 static struct acpi_driver acpi_power_driver = {
  76         .name = "power",
  77         .class = ACPI_POWER_CLASS,
  78         .ids = power_device_ids,
  79         .ops = {
  80                 .add = acpi_power_add,
  81                 .remove = acpi_power_remove,
  82                 },
  83         .drv.pm = &acpi_power_pm,
  84 };
  85
  86 /*
  87  * A power managed device
  88  * A device may rely on multiple power resources.
  89  * */
  90 struct acpi_power_managed_device {
  91         struct device *dev; /* The physical device */
  92         acpi_handle *handle;
  93 };
  94
  95 struct acpi_power_resource_device {
  96         struct acpi_power_managed_device *device;
  97         struct acpi_power_resource_device *next;
  98 };
  99
 100 struct acpi_power_resource {
 101         struct acpi_device * device;
 102         acpi_bus_id name;
 103         u32 system_level;
 104         u32 order;
 105         unsigned int ref_count;
 106         struct mutex resource_lock;
 107
 108         /* List of devices relying on this power resource */
 109         struct acpi_power_resource_device *devices;
 110         struct mutex devices_lock;
 111 };
 112
 113 static struct list_head acpi_power_resource_list;
 114
 115 /* --------------------------------------------------------------------------
 116                              Power Resource Management
 117    -------------------------------------------------------------------------- */
 118
 119 static int
 120 acpi_power_get_context(acpi_handle handle,
 121                        struct acpi_power_resource **resource)
 122 {
 123         int result = 0;
 124         struct acpi_device *device = NULL;
 125
 126
 127         if (!resource)
 128                 return -ENODEV;
 129
 130         result = acpi_bus_get_device(handle, &device);
 131         if (result) {
 132                 printk(KERN_WARNING PREFIX "Getting context [%p]\n", handle);
 133                 return result;
 134         }
 135
 136         *resource = acpi_driver_data(device);
 137         if (!*resource)
 138                 return -ENODEV;
 139
 140         return 0;
 141 }
 142
 143 static int acpi_power_get_state(acpi_handle handle, int *state)
 144 {
 145         acpi_status status = AE_OK;
 146         unsigned long long sta = 0;
 147         char node_name[5];
 148         struct acpi_buffer buffer = { sizeof(node_name), node_name };
 149
 150
 151         if (!handle || !state)
 152                 return -EINVAL;
 153
 154         status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
 155         if (ACPI_FAILURE(status))
 156                 return -ENODEV;
 157
 158         *state = (sta & 0x01)?ACPI_POWER_RESOURCE_STATE_ON:
 159                               ACPI_POWER_RESOURCE_STATE_OFF;
 160
 161         acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
 162
 163         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] is %s\n",
 164                           node_name,
 165                                 *state ? "on" : "off"));
 166
 167         return 0;
 168 }
 169
 170 static int acpi_power_get_list_state(struct acpi_handle_list *list, int *state)
 171 {
 172         int cur_state;
 173         int i = 0;
 174
 175         if (!list || !state)
 176                 return -EINVAL;
 177
 178         /* The state of the list is 'on' IFF all resources are 'on'. */
 179
 180         for (i = 0; i < list->count; i++) {
 181                 struct acpi_power_resource *resource;
 182                 acpi_handle handle = list->handles[i];
 183                 int result;
 184
 185                 result = acpi_power_get_context(handle, &resource);
 186                 if (result)
 187                         return result;
 188
 189                 mutex_lock(&resource->resource_lock);
 190
 191                 result = acpi_power_get_state(handle, &cur_state);
 192
 193                 mutex_unlock(&resource->resource_lock);
 194
 195                 if (result)
 196                         return result;
 197
 198                 if (cur_state != ACPI_POWER_RESOURCE_STATE_ON)
 199                         break;
 200         }
 201
 202         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource list is %s\n",
 203                           cur_state ? "on" : "off"));
 204
 205         *state = cur_state;
 206
 207         return 0;
 208 }
 209
 210 /* Resume the device when all power resources in _PR0 are on */
 211 static void acpi_power_on_device(struct acpi_power_managed_device *device)
 212 {
 213         struct acpi_device *acpi_dev;
 214         acpi_handle handle = device->handle;
 215         int state;
 216
 217         if (acpi_bus_get_device(handle, &acpi_dev))
 218                 return;
 219
 220         if(acpi_power_get_inferred_state(acpi_dev, &state))
 221                 return;
 222
 223         if (state == ACPI_STATE_D0 && pm_runtime_suspended(device->dev))
 224                 pm_request_resume(device->dev);
 225 }
 226
 227 static int __acpi_power_on(struct acpi_power_resource *resource)
 228 {
 229         acpi_status status = AE_OK;
 230
 231         status = acpi_evaluate_object(resource->device->handle, "_ON", NULL, NULL);
 232         if (ACPI_FAILURE(status))
 233                 return -ENODEV;
 234
 235         /* Update the power resource's _device_ power state */
 236         resource->device->power.state = ACPI_STATE_D0;
 237
 238         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Power resource [%s] turned on\n",
 239                           resource->name));
 240
 241         return 0;
 242 }
 243
 244 static int acpi_power_on(acpi_handle handle)
 245 {
 246         int result = 0;
 247         bool resume_device = false;
 248         struct acpi_power_resource *resource = NULL;
 249         struct acpi_power_resource_device *device_list;
 250
 251         result = acpi_power_get_context(handle, &resource);
 252         if (result)
 253                 return result;
 254
 255         mutex_lock(&resource->resource_lock);
 256
 257         if (resource->ref_count++) {
 258                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 259                                   "Power resource [%s] already on",
 260                                   resource->name));
 261         } else {
 262                 result = __acpi_power_on(resource);
 263                 if (result)
 264                         resource->ref_count--;
 265                 else
 266                         resume_device = true;
 267         }
 268
 269         mutex_unlock(&resource->resource_lock);
 270
 271         if (!resume_device)
 272                 return result;
 273
 274         mutex_lock(&resource->devices_lock);
 275
 276         device_list = resource->devices;
 277         while (device_list) {
 278                 acpi_power_on_device(device_list->device);
 279                 device_list = device_list->next;
 280         }
 281
 282         mutex_unlock(&resource->devices_lock);
 283
 284         return result;
 285 }
 286
 287 static int acpi_power_off(acpi_handle handle)
 288 {
 289         int result = 0;
 290         acpi_status status = AE_OK;
 291         struct acpi_power_resource *resource = NULL;
 292
 293         result = acpi_power_get_context(handle, &resource);
 294         if (result)
 295                 return result;
 296
 297         mutex_lock(&resource->resource_lock);
 298
 299         if (!resource->ref_count) {
 300                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 301                                   "Power resource [%s] already off",
 302                                   resource->name));
 303                 goto unlock;
 304         }
 305
 306         if (--resource->ref_count) {
 307                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 308                                   "Power resource [%s] still in use\n",
 309                                   resource->name));
 310                 goto unlock;
 311         }
 312
 313         status = acpi_evaluate_object(resource->device->handle, "_OFF", NULL, NULL);
 314         if (ACPI_FAILURE(status)) {
 315                 result = -ENODEV;
 316         } else {
 317                 /* Update the power resource's _device_ power state */
 318                 resource->device->power.state = ACPI_STATE_D3;
 319
 320                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 321                                   "Power resource [%s] turned off\n",
 322                                   resource->name));
 323         }
 324
 325  unlock:
 326         mutex_unlock(&resource->resource_lock);
 327
 328         return result;
 329 }
 330
 331 static void __acpi_power_off_list(struct acpi_handle_list *list, int num_res)
 332 {
 333         int i;
 334
 335         for (i = num_res - 1; i >= 0 ; i--)
 336                 acpi_power_off(list->handles[i]);
 337 }
 338
 339 static void acpi_power_off_list(struct acpi_handle_list *list)
 340 {
 341         __acpi_power_off_list(list, list->count);
 342 }
 343
 344 static int acpi_power_on_list(struct acpi_handle_list *list)
 345 {
 346         int result = 0;
 347         int i;
 348
 349         for (i = 0; i < list->count; i++) {
 350                 result = acpi_power_on(list->handles[i]);
 351                 if (result) {
 352                         __acpi_power_off_list(list, i);
 353                         break;
 354                 }
 355         }
 356
 357         return result;
 358 }
 359
 360 static void __acpi_power_resource_unregister_device(struct device *dev,
 361                 acpi_handle res_handle)
 362 {
 363         struct acpi_power_resource *resource = NULL;
 364         struct acpi_power_resource_device *prev, *curr;
 365
 366         if (acpi_power_get_context(res_handle, &resource))
 367                 return;
 368
 369         mutex_lock(&resource->devices_lock);
 370         prev = NULL;
 371         curr = resource->devices;
 372         while (curr) {
 373                 if (curr->device->dev == dev) {
 374                         if (!prev)
 375                                 resource->devices = curr->next;
 376                         else
 377                                 prev->next = curr->next;
 378
 379                         kfree(curr);
 380                         break;
 381                 }
 382
 383                 prev = curr;
 384                 curr = curr->next;
 385         }
 386         mutex_unlock(&resource->devices_lock);
 387 }
 388
 389 /* Unlink dev from all power resources in _PR0 */
 390 void acpi_power_resource_unregister_device(struct device *dev, acpi_handle handle)
 391 {
 392         struct acpi_device *acpi_dev;
 393         struct acpi_handle_list *list;
 394         int i;
 395
 396         if (!dev || !handle)
 397                 return;
 398
 399         if (acpi_bus_get_device(handle, &acpi_dev))
 400                 return;
 401
 402         list = &acpi_dev->power.states[ACPI_STATE_D0].resources;
 403
 404         for (i = 0; i < list->count; i++)
 405                 __acpi_power_resource_unregister_device(dev,
 406                         list->handles[i]);
 407 }
 408 EXPORT_SYMBOL_GPL(acpi_power_resource_unregister_device);
 409
 410 static int __acpi_power_resource_register_device(
 411         struct acpi_power_managed_device *powered_device, acpi_handle handle)
 412 {
 413         struct acpi_power_resource *resource = NULL;
 414         struct acpi_power_resource_device *power_resource_device;
 415         int result;
 416
 417         result = acpi_power_get_context(handle, &resource);
 418         if (result)
 419                 return result;
 420
 421         power_resource_device = kzalloc(
 422                 sizeof(*power_resource_device), GFP_KERNEL);
 423         if (!power_resource_device)
 424                 return -ENOMEM;
 425
 426         power_resource_device->device = powered_device;
 427
 428         mutex_lock(&resource->devices_lock);
 429         power_resource_device->next = resource->devices;
 430         resource->devices = power_resource_device;
 431         mutex_unlock(&resource->devices_lock);
 432
 433         return 0;
 434 }
 435
 436 /* Link dev to all power resources in _PR0 */
 437 int acpi_power_resource_register_device(struct device *dev, acpi_handle handle)
 438 {
 439         struct acpi_device *acpi_dev;
 440         struct acpi_handle_list *list;
 441         struct acpi_power_managed_device *powered_device;
 442         int i, ret;
 443
 444         if (!dev || !handle)
 445                 return -ENODEV;
 446
 447         ret = acpi_bus_get_device(handle, &acpi_dev);
 448         if (ret)
 449                 goto no_power_resource;
 450
 451         if (!acpi_dev->power.flags.power_resources)
 452                 goto no_power_resource;
 453
 454         powered_device = kzalloc(sizeof(*powered_device), GFP_KERNEL);
 455         if (!powered_device)
 456                 return -ENOMEM;
 457
 458         powered_device->dev = dev;
 459         powered_device->handle = handle;
 460
 461         list = &acpi_dev->power.states[ACPI_STATE_D0].resources;
 462
 463         for (i = 0; i < list->count; i++) {
 464                 ret = __acpi_power_resource_register_device(powered_device,
 465                         list->handles[i]);
 466
 467                 if (ret) {
 468                         acpi_power_resource_unregister_device(dev, handle);
 469                         break;
 470                 }
 471         }
 472
 473         return ret;
 474
 475 no_power_resource:
 476         printk(KERN_DEBUG PREFIX "Invalid Power Resource to register!\n");
 477         return -ENODEV;
 478 }
 479 EXPORT_SYMBOL_GPL(acpi_power_resource_register_device);
 480
 481 /**
 482  * acpi_device_sleep_wake - execute _DSW (Device Sleep Wake) or (deprecated in
 483  *                          ACPI 3.0) _PSW (Power State Wake)
 484  * @dev: Device to handle.
 485  * @enable: 0 - disable, 1 - enable the wake capabilities of the device.
 486  * @sleep_state: Target sleep state of the system.
 487  * @dev_state: Target power state of the device.
 488  *
 489  * Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
 490  * State Wake) for the device, if present.  On failure reset the device's
 491  * wakeup.flags.valid flag.
 492  *
 493  * RETURN VALUE:
 494  * 0 if either _DSW or _PSW has been successfully executed
 495  * 0 if neither _DSW nor _PSW has been found
 496  * -ENODEV if the execution of either _DSW or _PSW has failed
 497  */
 498 int acpi_device_sleep_wake(struct acpi_device *dev,
 499                            int enable, int sleep_state, int dev_state)
 500 {
 501         union acpi_object in_arg[3];
 502         struct acpi_object_list arg_list = { 3, in_arg };
 503         acpi_status status = AE_OK;
 504
 505         /*
 506          * Try to execute _DSW first.
 507          *
 508          * Three agruments are needed for the _DSW object:
 509          * Argument 0: enable/disable the wake capabilities
 510          * Argument 1: target system state
 511          * Argument 2: target device state
 512          * When _DSW object is called to disable the wake capabilities, maybe
 513          * the first argument is filled. The values of the other two agruments
 514          * are meaningless.
 515          */
 516         in_arg[0].type = ACPI_TYPE_INTEGER;
 517         in_arg[0].integer.value = enable;
 518         in_arg[1].type = ACPI_TYPE_INTEGER;
 519         in_arg[1].integer.value = sleep_state;
 520         in_arg[2].type = ACPI_TYPE_INTEGER;
 521         in_arg[2].integer.value = dev_state;
 522         status = acpi_evaluate_object(dev->handle, "_DSW", &arg_list, NULL);
 523         if (ACPI_SUCCESS(status)) {
 524                 return 0;
 525         } else if (status != AE_NOT_FOUND) {
 526                 printk(KERN_ERR PREFIX "_DSW execution failed\n");
 527                 dev->wakeup.flags.valid = 0;
 528                 return -ENODEV;
 529         }
 530
 531         /* Execute _PSW */
 532         arg_list.count = 1;
 533         in_arg[0].integer.value = enable;
 534         status = acpi_evaluate_object(dev->handle, "_PSW", &arg_list, NULL);
 535         if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {
 536                 printk(KERN_ERR PREFIX "_PSW execution failed\n");
 537                 dev->wakeup.flags.valid = 0;
 538                 return -ENODEV;
 539         }
 540
 541         return 0;
 542 }
 543
 544 /*
 545  * Prepare a wakeup device, two steps (Ref ACPI 2.0:P229):
 546  * 1. Power on the power resources required for the wakeup device
 547  * 2. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
 548  *    State Wake) for the device, if present
 549  */
 550 int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state)
 551 {
 552         int i, err = 0;
 553
 554         if (!dev || !dev->wakeup.flags.valid)
 555                 return -EINVAL;
 556
 557         mutex_lock(&acpi_device_lock);
 558
 559         if (dev->wakeup.prepare_count++)
 560                 goto out;
 561
 562         /* Open power resource */
 563         for (i = 0; i < dev->wakeup.resources.count; i++) {
 564                 int ret = acpi_power_on(dev->wakeup.resources.handles[i]);
 565                 if (ret) {
 566                         printk(KERN_ERR PREFIX "Transition power state\n");
 567                         dev->wakeup.flags.valid = 0;
 568                         err = -ENODEV;
 569                         goto err_out;
 570                 }
 571         }
 572
 573         /*
 574          * Passing 3 as the third argument below means the device may be placed
 575          * in arbitrary power state afterwards.
 576          */
 577         err = acpi_device_sleep_wake(dev, 1, sleep_state, 3);
 578
 579  err_out:
 580         if (err)
 581                 dev->wakeup.prepare_count = 0;
 582
 583  out:
 584         mutex_unlock(&acpi_device_lock);
 585         return err;
 586 }
 587
 588 /*
 589  * Shutdown a wakeup device, counterpart of above method
 590  * 1. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
 591  *    State Wake) for the device, if present
 592  * 2. Shutdown down the power resources
 593  */
 594 int acpi_disable_wakeup_device_power(struct acpi_device *dev)
 595 {
 596         int i, err = 0;
 597
 598         if (!dev || !dev->wakeup.flags.valid)
 599                 return -EINVAL;
 600
 601         mutex_lock(&acpi_device_lock);
 602
 603         if (--dev->wakeup.prepare_count > 0)
 604                 goto out;
 605
 606         /*
 607          * Executing the code below even if prepare_count is already zero when
 608          * the function is called may be useful, for example for initialisation.
 609          */
 610         if (dev->wakeup.prepare_count < 0)
 611                 dev->wakeup.prepare_count = 0;
 612
 613         err = acpi_device_sleep_wake(dev, 0, 0, 0);
 614         if (err)
 615                 goto out;
 616
 617         /* Close power resource */
 618         for (i = 0; i < dev->wakeup.resources.count; i++) {
 619                 int ret = acpi_power_off(dev->wakeup.resources.handles[i]);
 620                 if (ret) {
 621                         printk(KERN_ERR PREFIX "Transition power state\n");
 622                         dev->wakeup.flags.valid = 0;
 623                         err = -ENODEV;
 624                         goto out;
 625                 }
 626         }
 627
 628  out:
 629         mutex_unlock(&acpi_device_lock);
 630         return err;
 631 }
 632
 633 /* --------------------------------------------------------------------------
 634                              Device Power Management
 635    -------------------------------------------------------------------------- */
 636
 637 int acpi_power_get_inferred_state(struct acpi_device *device, int *state)
 638 {
 639         int result = 0;
 640         struct acpi_handle_list *list = NULL;
 641         int list_state = 0;
 642         int i = 0;
 643
 644         if (!device || !state)
 645                 return -EINVAL;
 646
 647         /*
 648          * We know a device's inferred power state when all the resources
 649          * required for a given D-state are 'on'.
 650          */
 651         for (i = ACPI_STATE_D0; i <= ACPI_STATE_D3_HOT; i++) {
 652                 list = &device->power.states[i].resources;
 653                 if (list->count < 1)
 654                         continue;
 655
 656                 result = acpi_power_get_list_state(list, &list_state);
 657                 if (result)
 658                         return result;
 659
 660                 if (list_state == ACPI_POWER_RESOURCE_STATE_ON) {
 661                         *state = i;
 662                         return 0;
 663                 }
 664         }
 665
 666         *state = ACPI_STATE_D3;
 667         return 0;
 668 }
 669
 670 int acpi_power_on_resources(struct acpi_device *device, int state)
 671 {
 672         if (!device || state < ACPI_STATE_D0 || state > ACPI_STATE_D3)
 673                 return -EINVAL;
 674
 675         return acpi_power_on_list(&device->power.states[state].resources);
 676 }
 677
 678 int acpi_power_transition(struct acpi_device *device, int state)
 679 {
 680         int result = 0;
 681
 682         if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD))
 683                 return -EINVAL;
 684
 685         if (device->power.state == state)
 686                 return 0;
 687
 688         if ((device->power.state < ACPI_STATE_D0)
 689             || (device->power.state > ACPI_STATE_D3_COLD))
 690                 return -ENODEV;
 691
 692         /* TBD: Resources must be ordered. */
 693
 694         /*
 695          * First we reference all power resources required in the target list
 696          * (e.g. so the device doesn't lose power while transitioning).  Then,
 697          * we dereference all power resources used in the current list.
 698          */
 699         if (state < ACPI_STATE_D3_COLD)
 700                 result = acpi_power_on_list(
 701                         &device->power.states[state].resources);
 702
 703         if (!result && device->power.state < ACPI_STATE_D3_COLD)
 704                 acpi_power_off_list(
 705                         &device->power.states[device->power.state].resources);
 706
 707         /* We shouldn't change the state unless the above operations succeed. */
 708         device->power.state = result ? ACPI_STATE_UNKNOWN : state;
 709
 710         return result;
 711 }
 712
 713 /* --------------------------------------------------------------------------
 714                                 Driver Interface
 715    -------------------------------------------------------------------------- */
 716
 717 static int acpi_power_add(struct acpi_device *device)
 718 {
 719         int result = 0, state;
 720         acpi_status status = AE_OK;
 721         struct acpi_power_resource *resource = NULL;
 722         union acpi_object acpi_object;
 723         struct acpi_buffer buffer = { sizeof(acpi_object), &acpi_object };
 724
 725
 726         if (!device)
 727                 return -EINVAL;
 728
 729         resource = kzalloc(sizeof(struct acpi_power_resource), GFP_KERNEL);
 730         if (!resource)
 731                 return -ENOMEM;
 732
 733         resource->device = device;
 734         mutex_init(&resource->resource_lock);
 735         mutex_init(&resource->devices_lock);
 736         strcpy(resource->name, device->pnp.bus_id);
 737         strcpy(acpi_device_name(device), ACPI_POWER_DEVICE_NAME);
 738         strcpy(acpi_device_class(device), ACPI_POWER_CLASS);
 739         device->driver_data = resource;
 740
 741         /* Evalute the object to get the system level and resource order. */
 742         status = acpi_evaluate_object(device->handle, NULL, NULL, &buffer);
 743         if (ACPI_FAILURE(status)) {
 744                 result = -ENODEV;
 745                 goto end;
 746         }
 747         resource->system_level = acpi_object.power_resource.system_level;
 748         resource->order = acpi_object.power_resource.resource_order;
 749
 750         result = acpi_power_get_state(device->handle, &state);
 751         if (result)
 752                 goto end;
 753
 754         switch (state) {
 755         case ACPI_POWER_RESOURCE_STATE_ON:
 756                 device->power.state = ACPI_STATE_D0;
 757                 break;
 758         case ACPI_POWER_RESOURCE_STATE_OFF:
 759                 device->power.state = ACPI_STATE_D3;
 760                 break;
 761         default:
 762                 device->power.state = ACPI_STATE_UNKNOWN;
 763                 break;
 764         }
 765
 766         printk(KERN_INFO PREFIX "%s [%s] (%s)\n", acpi_device_name(device),
 767                acpi_device_bid(device), state ? "on" : "off");
 768
 769       end:
 770         if (result)
 771                 kfree(resource);
 772
 773         return result;
 774 }
 775
 776 static int acpi_power_remove(struct acpi_device *device, int type)
 777 {
 778         struct acpi_power_resource *resource;
 779
 780         if (!device)
 781                 return -EINVAL;
 782
 783         resource = acpi_driver_data(device);
 784         if (!resource)
 785                 return -EINVAL;
 786
 787         kfree(resource);
 788
 789         return 0;
 790 }
 791
 792 #ifdef CONFIG_PM_SLEEP
 793 static int acpi_power_resume(struct device *dev)
 794 {
 795         int result = 0, state;
 796         struct acpi_device *device;
 797         struct acpi_power_resource *resource;
 798
 799         if (!dev)
 800                 return -EINVAL;
 801
 802         device = to_acpi_device(dev);
 803         resource = acpi_driver_data(device);
 804         if (!resource)
 805                 return -EINVAL;
 806
 807         mutex_lock(&resource->resource_lock);
 808
 809         result = acpi_power_get_state(device->handle, &state);
 810         if (result)
 811                 goto unlock;
 812
 813         if (state == ACPI_POWER_RESOURCE_STATE_OFF && resource->ref_count)
 814                 result = __acpi_power_on(resource);
 815
 816  unlock:
 817         mutex_unlock(&resource->resource_lock);
 818
 819         return result;
 820 }
 821 #endif
 822
 823 int __init acpi_power_init(void)
 824 {
 825         INIT_LIST_HEAD(&acpi_power_resource_list);
 826         return acpi_bus_register_driver(&acpi_power_driver);
 827 }