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/proc_fs.h>
  43 #include <linux/seq_file.h>
  44 #include <acpi/acpi_bus.h>
  45 #include <acpi/acpi_drivers.h>
  46
  47 #define _COMPONENT              ACPI_POWER_COMPONENT
  48 ACPI_MODULE_NAME("power");
  49 #define ACPI_POWER_COMPONENT            0x00800000
  50 #define ACPI_POWER_CLASS                "power_resource"
  51 #define ACPI_POWER_DEVICE_NAME          "Power Resource"
  52 #define ACPI_POWER_FILE_INFO            "info"
  53 #define ACPI_POWER_FILE_STATUS          "state"
  54 #define ACPI_POWER_RESOURCE_STATE_OFF   0x00
  55 #define ACPI_POWER_RESOURCE_STATE_ON    0x01
  56 #define ACPI_POWER_RESOURCE_STATE_UNKNOWN 0xFF
  57
  58 #ifdef MODULE_PARAM_PREFIX
  59 #undef MODULE_PARAM_PREFIX
  60 #endif
  61 #define MODULE_PARAM_PREFIX "acpi."
  62 int acpi_power_nocheck;
  63 module_param_named(power_nocheck, acpi_power_nocheck, bool, 000);
  64
  65 static int acpi_power_add(struct acpi_device *device);
  66 static int acpi_power_remove(struct acpi_device *device, int type);
  67 static int acpi_power_resume(struct acpi_device *device);
  68 static int acpi_power_open_fs(struct inode *inode, struct file *file);
  69
  70 static struct acpi_device_id power_device_ids[] = {
  71         {ACPI_POWER_HID, 0},
  72         {"", 0},
  73 };
  74 MODULE_DEVICE_TABLE(acpi, power_device_ids);
  75
  76 static struct acpi_driver acpi_power_driver = {
  77         .name = "power",
  78         .class = ACPI_POWER_CLASS,
  79         .ids = power_device_ids,
  80         .ops = {
  81                 .add = acpi_power_add,
  82                 .remove = acpi_power_remove,
  83                 .resume = acpi_power_resume,
  84                 },
  85 };
  86
  87 struct acpi_power_reference {
  88         struct list_head node;
  89         struct acpi_device *device;
  90 };
  91
  92 struct acpi_power_resource {
  93         struct acpi_device * device;
  94         acpi_bus_id name;
  95         u32 system_level;
  96         u32 order;
  97         struct mutex resource_lock;
  98         struct list_head reference;
  99 };
 100
 101 static struct list_head acpi_power_resource_list;
 102
 103 static const struct file_operations acpi_power_fops = {
 104         .owner = THIS_MODULE,
 105         .open = acpi_power_open_fs,
 106         .read = seq_read,
 107         .llseek = seq_lseek,
 108         .release = single_release,
 109 };
 110
 111 /* --------------------------------------------------------------------------
 112                              Power Resource Management
 113    -------------------------------------------------------------------------- */
 114
 115 static int
 116 acpi_power_get_context(acpi_handle handle,
 117                        struct acpi_power_resource **resource)
 118 {
 119         int result = 0;
 120         struct acpi_device *device = NULL;
 121
 122
 123         if (!resource)
 124                 return -ENODEV;
 125
 126         result = acpi_bus_get_device(handle, &device);
 127         if (result) {
 128                 printk(KERN_WARNING PREFIX "Getting context [%p]\n", handle);
 129                 return result;
 130         }
 131
 132         *resource = acpi_driver_data(device);
 133         if (!*resource)
 134                 return -ENODEV;
 135
 136         return 0;
 137 }
 138
 139 static int acpi_power_get_state(acpi_handle handle, int *state)
 140 {
 141         acpi_status status = AE_OK;
 142         unsigned long long sta = 0;
 143
 144
 145         if (!handle || !state)
 146                 return -EINVAL;
 147
 148         status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
 149         if (ACPI_FAILURE(status))
 150                 return -ENODEV;
 151
 152         *state = (sta & 0x01)?ACPI_POWER_RESOURCE_STATE_ON:
 153                               ACPI_POWER_RESOURCE_STATE_OFF;
 154
 155         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] is %s\n",
 156                           acpi_ut_get_node_name(handle), state ? "on" : "off"));
 157
 158         return 0;
 159 }
 160
 161 static int acpi_power_get_list_state(struct acpi_handle_list *list, int *state)
 162 {
 163         int result = 0, state1;
 164         u32 i = 0;
 165
 166
 167         if (!list || !state)
 168                 return -EINVAL;
 169
 170         /* The state of the list is 'on' IFF all resources are 'on'. */
 171         /* */
 172
 173         for (i = 0; i < list->count; i++) {
 174                 /*
 175                  * The state of the power resource can be obtained by
 176                  * using the ACPI handle. In such case it is unnecessary to
 177                  * get the Power resource first and then get its state again.
 178                  */
 179                 result = acpi_power_get_state(list->handles[i], &state1);
 180                 if (result)
 181                         return result;
 182
 183                 *state = state1;
 184
 185                 if (*state != ACPI_POWER_RESOURCE_STATE_ON)
 186                         break;
 187         }
 188
 189         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource list is %s\n",
 190                           *state ? "on" : "off"));
 191
 192         return result;
 193 }
 194
 195 static int acpi_power_on(acpi_handle handle, struct acpi_device *dev)
 196 {
 197         int result = 0, state;
 198         int found = 0;
 199         acpi_status status = AE_OK;
 200         struct acpi_power_resource *resource = NULL;
 201         struct list_head *node, *next;
 202         struct acpi_power_reference *ref;
 203
 204
 205         result = acpi_power_get_context(handle, &resource);
 206         if (result)
 207                 return result;
 208
 209         mutex_lock(&resource->resource_lock);
 210         list_for_each_safe(node, next, &resource->reference) {
 211                 ref = container_of(node, struct acpi_power_reference, node);
 212                 if (dev->handle == ref->device->handle) {
 213                         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] already referenced by resource [%s]\n",
 214                                   dev->pnp.bus_id, resource->name));
 215                         found = 1;
 216                         break;
 217                 }
 218         }
 219
 220         if (!found) {
 221                 ref = kmalloc(sizeof (struct acpi_power_reference),
 222                     irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL);
 223                 if (!ref) {
 224                         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "kmalloc() failed\n"));
 225                         mutex_unlock(&resource->resource_lock);
 226                         return -ENOMEM;
 227                 }
 228                 list_add_tail(&ref->node, &resource->reference);
 229                 ref->device = dev;
 230                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] added to resource [%s] references\n",
 231                           dev->pnp.bus_id, resource->name));
 232         }
 233         mutex_unlock(&resource->resource_lock);
 234
 235         status = acpi_evaluate_object(resource->device->handle, "_ON", NULL, NULL);
 236         if (ACPI_FAILURE(status))
 237                 return -ENODEV;
 238
 239         if (!acpi_power_nocheck) {
 240                 /*
 241                  * If acpi_power_nocheck is set, it is unnecessary to check
 242                  * the power state after power transition.
 243                  */
 244                 result = acpi_power_get_state(resource->device->handle,
 245                                 &state);
 246                 if (result)
 247                         return result;
 248                 if (state != ACPI_POWER_RESOURCE_STATE_ON)
 249                         return -ENOEXEC;
 250         }
 251         /* Update the power resource's _device_ power state */
 252         resource->device->power.state = ACPI_STATE_D0;
 253
 254         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] turned on\n",
 255                           resource->name));
 256         return 0;
 257 }
 258
 259 static int acpi_power_off_device(acpi_handle handle, struct acpi_device *dev)
 260 {
 261         int result = 0, state;
 262         acpi_status status = AE_OK;
 263         struct acpi_power_resource *resource = NULL;
 264         struct list_head *node, *next;
 265         struct acpi_power_reference *ref;
 266
 267
 268         result = acpi_power_get_context(handle, &resource);
 269         if (result)
 270                 return result;
 271
 272         mutex_lock(&resource->resource_lock);
 273         list_for_each_safe(node, next, &resource->reference) {
 274                 ref = container_of(node, struct acpi_power_reference, node);
 275                 if (dev->handle == ref->device->handle) {
 276                         list_del(&ref->node);
 277                         kfree(ref);
 278                         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] removed from resource [%s] references\n",
 279                             dev->pnp.bus_id, resource->name));
 280                         break;
 281                 }
 282         }
 283
 284         if (!list_empty(&resource->reference)) {
 285                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Cannot turn resource [%s] off - resource is in use\n",
 286                     resource->name));
 287                 mutex_unlock(&resource->resource_lock);
 288                 return 0;
 289         }
 290         mutex_unlock(&resource->resource_lock);
 291
 292         status = acpi_evaluate_object(resource->device->handle, "_OFF", NULL, NULL);
 293         if (ACPI_FAILURE(status))
 294                 return -ENODEV;
 295
 296         if (!acpi_power_nocheck) {
 297                 /*
 298                  * If acpi_power_nocheck is set, it is unnecessary to check
 299                  * the power state after power transition.
 300                  */
 301                 result = acpi_power_get_state(handle, &state);
 302                 if (result)
 303                         return result;
 304                 if (state != ACPI_POWER_RESOURCE_STATE_OFF)
 305                         return -ENOEXEC;
 306         }
 307
 308         /* Update the power resource's _device_ power state */
 309         resource->device->power.state = ACPI_STATE_D3;
 310
 311         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] turned off\n",
 312                           resource->name));
 313
 314         return 0;
 315 }
 316
 317 /**
 318  * acpi_device_sleep_wake - execute _DSW (Device Sleep Wake) or (deprecated in
 319  *                          ACPI 3.0) _PSW (Power State Wake)
 320  * @dev: Device to handle.
 321  * @enable: 0 - disable, 1 - enable the wake capabilities of the device.
 322  * @sleep_state: Target sleep state of the system.
 323  * @dev_state: Target power state of the device.
 324  *
 325  * Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
 326  * State Wake) for the device, if present.  On failure reset the device's
 327  * wakeup.flags.valid flag.
 328  *
 329  * RETURN VALUE:
 330  * 0 if either _DSW or _PSW has been successfully executed
 331  * 0 if neither _DSW nor _PSW has been found
 332  * -ENODEV if the execution of either _DSW or _PSW has failed
 333  */
 334 int acpi_device_sleep_wake(struct acpi_device *dev,
 335                            int enable, int sleep_state, int dev_state)
 336 {
 337         union acpi_object in_arg[3];
 338         struct acpi_object_list arg_list = { 3, in_arg };
 339         acpi_status status = AE_OK;
 340
 341         /*
 342          * Try to execute _DSW first.
 343          *
 344          * Three agruments are needed for the _DSW object:
 345          * Argument 0: enable/disable the wake capabilities
 346          * Argument 1: target system state
 347          * Argument 2: target device state
 348          * When _DSW object is called to disable the wake capabilities, maybe
 349          * the first argument is filled. The values of the other two agruments
 350          * are meaningless.
 351          */
 352         in_arg[0].type = ACPI_TYPE_INTEGER;
 353         in_arg[0].integer.value = enable;
 354         in_arg[1].type = ACPI_TYPE_INTEGER;
 355         in_arg[1].integer.value = sleep_state;
 356         in_arg[2].type = ACPI_TYPE_INTEGER;
 357         in_arg[2].integer.value = dev_state;
 358         status = acpi_evaluate_object(dev->handle, "_DSW", &arg_list, NULL);
 359         if (ACPI_SUCCESS(status)) {
 360                 return 0;
 361         } else if (status != AE_NOT_FOUND) {
 362                 printk(KERN_ERR PREFIX "_DSW execution failed\n");
 363                 dev->wakeup.flags.valid = 0;
 364                 return -ENODEV;
 365         }
 366
 367         /* Execute _PSW */
 368         arg_list.count = 1;
 369         in_arg[0].integer.value = enable;
 370         status = acpi_evaluate_object(dev->handle, "_PSW", &arg_list, NULL);
 371         if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {
 372                 printk(KERN_ERR PREFIX "_PSW execution failed\n");
 373                 dev->wakeup.flags.valid = 0;
 374                 return -ENODEV;
 375         }
 376
 377         return 0;
 378 }
 379
 380 /*
 381  * Prepare a wakeup device, two steps (Ref ACPI 2.0:P229):
 382  * 1. Power on the power resources required for the wakeup device
 383  * 2. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
 384  *    State Wake) for the device, if present
 385  */
 386 int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state)
 387 {
 388         int i, err;
 389
 390         if (!dev || !dev->wakeup.flags.valid)
 391                 return -EINVAL;
 392
 393         /*
 394          * Do not execute the code below twice in a row without calling
 395          * acpi_disable_wakeup_device_power() in between for the same device
 396          */
 397         if (dev->wakeup.flags.prepared)
 398                 return 0;
 399
 400         /* Open power resource */
 401         for (i = 0; i < dev->wakeup.resources.count; i++) {
 402                 int ret = acpi_power_on(dev->wakeup.resources.handles[i], dev);
 403                 if (ret) {
 404                         printk(KERN_ERR PREFIX "Transition power state\n");
 405                         dev->wakeup.flags.valid = 0;
 406                         return -ENODEV;
 407                 }
 408         }
 409
 410         /*
 411          * Passing 3 as the third argument below means the device may be placed
 412          * in arbitrary power state afterwards.
 413          */
 414         err = acpi_device_sleep_wake(dev, 1, sleep_state, 3);
 415         if (!err)
 416                 dev->wakeup.flags.prepared = 1;
 417
 418         return err;
 419 }
 420
 421 /*
 422  * Shutdown a wakeup device, counterpart of above method
 423  * 1. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
 424  *    State Wake) for the device, if present
 425  * 2. Shutdown down the power resources
 426  */
 427 int acpi_disable_wakeup_device_power(struct acpi_device *dev)
 428 {
 429         int i, ret;
 430
 431         if (!dev || !dev->wakeup.flags.valid)
 432                 return -EINVAL;
 433
 434         /*
 435          * Do not execute the code below twice in a row without calling
 436          * acpi_enable_wakeup_device_power() in between for the same device
 437          */
 438         if (!dev->wakeup.flags.prepared)
 439                 return 0;
 440
 441         dev->wakeup.flags.prepared = 0;
 442
 443         ret = acpi_device_sleep_wake(dev, 0, 0, 0);
 444         if (ret)
 445                 return ret;
 446
 447         /* Close power resource */
 448         for (i = 0; i < dev->wakeup.resources.count; i++) {
 449                 ret = acpi_power_off_device(dev->wakeup.resources.handles[i], dev);
 450                 if (ret) {
 451                         printk(KERN_ERR PREFIX "Transition power state\n");
 452                         dev->wakeup.flags.valid = 0;
 453                         return -ENODEV;
 454                 }
 455         }
 456
 457         return ret;
 458 }
 459
 460 /* --------------------------------------------------------------------------
 461                              Device Power Management
 462    -------------------------------------------------------------------------- */
 463
 464 int acpi_power_get_inferred_state(struct acpi_device *device)
 465 {
 466         int result = 0;
 467         struct acpi_handle_list *list = NULL;
 468         int list_state = 0;
 469         int i = 0;
 470
 471
 472         if (!device)
 473                 return -EINVAL;
 474
 475         device->power.state = ACPI_STATE_UNKNOWN;
 476
 477         /*
 478          * We know a device's inferred power state when all the resources
 479          * required for a given D-state are 'on'.
 480          */
 481         for (i = ACPI_STATE_D0; i < ACPI_STATE_D3; i++) {
 482                 list = &device->power.states[i].resources;
 483                 if (list->count < 1)
 484                         continue;
 485
 486                 result = acpi_power_get_list_state(list, &list_state);
 487                 if (result)
 488                         return result;
 489
 490                 if (list_state == ACPI_POWER_RESOURCE_STATE_ON) {
 491                         device->power.state = i;
 492                         return 0;
 493                 }
 494         }
 495
 496         device->power.state = ACPI_STATE_D3;
 497
 498         return 0;
 499 }
 500
 501 int acpi_power_transition(struct acpi_device *device, int state)
 502 {
 503         int result = 0;
 504         struct acpi_handle_list *cl = NULL;     /* Current Resources */
 505         struct acpi_handle_list *tl = NULL;     /* Target Resources */
 506         int i = 0;
 507
 508
 509         if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3))
 510                 return -EINVAL;
 511
 512         if ((device->power.state < ACPI_STATE_D0)
 513             || (device->power.state > ACPI_STATE_D3))
 514                 return -ENODEV;
 515
 516         cl = &device->power.states[device->power.state].resources;
 517         tl = &device->power.states[state].resources;
 518
 519         if (!cl->count && !tl->count) {
 520                 result = -ENODEV;
 521                 goto end;
 522         }
 523
 524         /* TBD: Resources must be ordered. */
 525
 526         /*
 527          * First we reference all power resources required in the target list
 528          * (e.g. so the device doesn't lose power while transitioning).
 529          */
 530         for (i = 0; i < tl->count; i++) {
 531                 result = acpi_power_on(tl->handles[i], device);
 532                 if (result)
 533                         goto end;
 534         }
 535
 536         if (device->power.state == state) {
 537                 goto end;
 538         }
 539
 540         /*
 541          * Then we dereference all power resources used in the current list.
 542          */
 543         for (i = 0; i < cl->count; i++) {
 544                 result = acpi_power_off_device(cl->handles[i], device);
 545                 if (result)
 546                         goto end;
 547         }
 548
 549      end:
 550         if (result)
 551                 device->power.state = ACPI_STATE_UNKNOWN;
 552         else {
 553         /* We shouldn't change the state till all above operations succeed */
 554                 device->power.state = state;
 555         }
 556
 557         return result;
 558 }
 559
 560 /* --------------------------------------------------------------------------
 561                               FS Interface (/proc)
 562    -------------------------------------------------------------------------- */
 563
 564 static struct proc_dir_entry *acpi_power_dir;
 565
 566 static int acpi_power_seq_show(struct seq_file *seq, void *offset)
 567 {
 568         int count = 0;
 569         int result = 0, state;
 570         struct acpi_power_resource *resource = NULL;
 571         struct list_head *node, *next;
 572         struct acpi_power_reference *ref;
 573
 574
 575         resource = seq->private;
 576
 577         if (!resource)
 578                 goto end;
 579
 580         result = acpi_power_get_state(resource->device->handle, &state);
 581         if (result)
 582                 goto end;
 583
 584         seq_puts(seq, "state:                   ");
 585         switch (state) {
 586         case ACPI_POWER_RESOURCE_STATE_ON:
 587                 seq_puts(seq, "on\n");
 588                 break;
 589         case ACPI_POWER_RESOURCE_STATE_OFF:
 590                 seq_puts(seq, "off\n");
 591                 break;
 592         default:
 593                 seq_puts(seq, "unknown\n");
 594                 break;
 595         }
 596
 597         mutex_lock(&resource->resource_lock);
 598         list_for_each_safe(node, next, &resource->reference) {
 599                 ref = container_of(node, struct acpi_power_reference, node);
 600                 count++;
 601         }
 602         mutex_unlock(&resource->resource_lock);
 603
 604         seq_printf(seq, "system level:            S%d\n"
 605                    "order:                   %d\n"
 606                    "reference count:         %d\n",
 607                    resource->system_level,
 608                    resource->order, count);
 609
 610       end:
 611         return 0;
 612 }
 613
 614 static int acpi_power_open_fs(struct inode *inode, struct file *file)
 615 {
 616         return single_open(file, acpi_power_seq_show, PDE(inode)->data);
 617 }
 618
 619 static int acpi_power_add_fs(struct acpi_device *device)
 620 {
 621         struct proc_dir_entry *entry = NULL;
 622
 623
 624         if (!device)
 625                 return -EINVAL;
 626
 627         if (!acpi_device_dir(device)) {
 628                 acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device),
 629                                                      acpi_power_dir);
 630                 if (!acpi_device_dir(device))
 631                         return -ENODEV;
 632         }
 633
 634         /* 'status' [R] */
 635         entry = proc_create_data(ACPI_POWER_FILE_STATUS,
 636                                  S_IRUGO, acpi_device_dir(device),
 637                                  &acpi_power_fops, acpi_driver_data(device));
 638         if (!entry)
 639                 return -EIO;
 640         return 0;
 641 }
 642
 643 static int acpi_power_remove_fs(struct acpi_device *device)
 644 {
 645
 646         if (acpi_device_dir(device)) {
 647                 remove_proc_entry(ACPI_POWER_FILE_STATUS,
 648                                   acpi_device_dir(device));
 649                 remove_proc_entry(acpi_device_bid(device), acpi_power_dir);
 650                 acpi_device_dir(device) = NULL;
 651         }
 652
 653         return 0;
 654 }
 655
 656 /* --------------------------------------------------------------------------
 657                                 Driver Interface
 658    -------------------------------------------------------------------------- */
 659
 660 static int acpi_power_add(struct acpi_device *device)
 661 {
 662         int result = 0, state;
 663         acpi_status status = AE_OK;
 664         struct acpi_power_resource *resource = NULL;
 665         union acpi_object acpi_object;
 666         struct acpi_buffer buffer = { sizeof(acpi_object), &acpi_object };
 667
 668
 669         if (!device)
 670                 return -EINVAL;
 671
 672         resource = kzalloc(sizeof(struct acpi_power_resource), GFP_KERNEL);
 673         if (!resource)
 674                 return -ENOMEM;
 675
 676         resource->device = device;
 677         mutex_init(&resource->resource_lock);
 678         INIT_LIST_HEAD(&resource->reference);
 679         strcpy(resource->name, device->pnp.bus_id);
 680         strcpy(acpi_device_name(device), ACPI_POWER_DEVICE_NAME);
 681         strcpy(acpi_device_class(device), ACPI_POWER_CLASS);
 682         device->driver_data = resource;
 683
 684         /* Evalute the object to get the system level and resource order. */
 685         status = acpi_evaluate_object(device->handle, NULL, NULL, &buffer);
 686         if (ACPI_FAILURE(status)) {
 687                 result = -ENODEV;
 688                 goto end;
 689         }
 690         resource->system_level = acpi_object.power_resource.system_level;
 691         resource->order = acpi_object.power_resource.resource_order;
 692
 693         result = acpi_power_get_state(device->handle, &state);
 694         if (result)
 695                 goto end;
 696
 697         switch (state) {
 698         case ACPI_POWER_RESOURCE_STATE_ON:
 699                 device->power.state = ACPI_STATE_D0;
 700                 break;
 701         case ACPI_POWER_RESOURCE_STATE_OFF:
 702                 device->power.state = ACPI_STATE_D3;
 703                 break;
 704         default:
 705                 device->power.state = ACPI_STATE_UNKNOWN;
 706                 break;
 707         }
 708
 709         result = acpi_power_add_fs(device);
 710         if (result)
 711                 goto end;
 712
 713         printk(KERN_INFO PREFIX "%s [%s] (%s)\n", acpi_device_name(device),
 714                acpi_device_bid(device), state ? "on" : "off");
 715
 716       end:
 717         if (result)
 718                 kfree(resource);
 719
 720         return result;
 721 }
 722
 723 static int acpi_power_remove(struct acpi_device *device, int type)
 724 {
 725         struct acpi_power_resource *resource = NULL;
 726         struct list_head *node, *next;
 727
 728
 729         if (!device || !acpi_driver_data(device))
 730                 return -EINVAL;
 731
 732         resource = acpi_driver_data(device);
 733
 734         acpi_power_remove_fs(device);
 735
 736         mutex_lock(&resource->resource_lock);
 737         list_for_each_safe(node, next, &resource->reference) {
 738                 struct acpi_power_reference *ref = container_of(node, struct acpi_power_reference, node);
 739                 list_del(&ref->node);
 740                 kfree(ref);
 741         }
 742         mutex_unlock(&resource->resource_lock);
 743
 744         kfree(resource);
 745
 746         return 0;
 747 }
 748
 749 static int acpi_power_resume(struct acpi_device *device)
 750 {
 751         int result = 0, state;
 752         struct acpi_power_resource *resource = NULL;
 753         struct acpi_power_reference *ref;
 754
 755         if (!device || !acpi_driver_data(device))
 756                 return -EINVAL;
 757
 758         resource = acpi_driver_data(device);
 759
 760         result = acpi_power_get_state(device->handle, &state);
 761         if (result)
 762                 return result;
 763
 764         mutex_lock(&resource->resource_lock);
 765         if (state == ACPI_POWER_RESOURCE_STATE_OFF &&
 766             !list_empty(&resource->reference)) {
 767                 ref = container_of(resource->reference.next, struct acpi_power_reference, node);
 768                 mutex_unlock(&resource->resource_lock);
 769                 result = acpi_power_on(device->handle, ref->device);
 770                 return result;
 771         }
 772
 773         mutex_unlock(&resource->resource_lock);
 774         return 0;
 775 }
 776
 777 static int __init acpi_power_init(void)
 778 {
 779         int result = 0;
 780
 781
 782         if (acpi_disabled)
 783                 return 0;
 784
 785         INIT_LIST_HEAD(&acpi_power_resource_list);
 786
 787         acpi_power_dir = proc_mkdir(ACPI_POWER_CLASS, acpi_root_dir);
 788         if (!acpi_power_dir)
 789                 return -ENODEV;
 790
 791         result = acpi_bus_register_driver(&acpi_power_driver);
 792         if (result < 0) {
 793                 remove_proc_entry(ACPI_POWER_CLASS, acpi_root_dir);
 794                 return -ENODEV;
 795         }
 796
 797         return 0;
 798 }
 799
 800 subsys_initcall(acpi_power_init);