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