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