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