git.oblomov.eu Git - linux-2.6/blob - drivers/acpi/scan.c

   1 /*
   2  * scan.c - support for transforming the ACPI namespace into individual objects
   3  */
   4
   5 #include <linux/module.h>
   6 #include <linux/init.h>
   7 #include <linux/acpi.h>
   8
   9 #include <acpi/acpi_drivers.h>
  10 #include <acpi/acinterp.h>      /* for acpi_ex_eisa_id_to_string() */
  11
  12 #define _COMPONENT              ACPI_BUS_COMPONENT
  13 ACPI_MODULE_NAME("scan")
  14 #define STRUCT_TO_INT(s)        (*((int*)&s))
  15 extern struct acpi_device *acpi_root;
  16
  17 #define ACPI_BUS_CLASS                  "system_bus"
  18 #define ACPI_BUS_HID                    "ACPI_BUS"
  19 #define ACPI_BUS_DRIVER_NAME            "ACPI Bus Driver"
  20 #define ACPI_BUS_DEVICE_NAME            "System Bus"
  21
  22 static LIST_HEAD(acpi_device_list);
  23 DEFINE_SPINLOCK(acpi_device_lock);
  24 LIST_HEAD(acpi_wakeup_device_list);
  25
  26
  27 static void acpi_device_release(struct kobject *kobj)
  28 {
  29         struct acpi_device *dev = container_of(kobj, struct acpi_device, kobj);
  30         kfree(dev->pnp.cid_list);
  31         kfree(dev);
  32 }
  33
  34 struct acpi_device_attribute {
  35         struct attribute attr;
  36          ssize_t(*show) (struct acpi_device *, char *);
  37          ssize_t(*store) (struct acpi_device *, const char *, size_t);
  38 };
  39
  40 typedef void acpi_device_sysfs_files(struct kobject *,
  41                                      const struct attribute *);
  42
  43 static void setup_sys_fs_device_files(struct acpi_device *dev,
  44                                       acpi_device_sysfs_files * func);
  45
  46 #define create_sysfs_device_files(dev)  \
  47         setup_sys_fs_device_files(dev, (acpi_device_sysfs_files *)&sysfs_create_file)
  48 #define remove_sysfs_device_files(dev)  \
  49         setup_sys_fs_device_files(dev, (acpi_device_sysfs_files *)&sysfs_remove_file)
  50
  51 #define to_acpi_device(n) container_of(n, struct acpi_device, kobj)
  52 #define to_handle_attr(n) container_of(n, struct acpi_device_attribute, attr);
  53
  54 static ssize_t acpi_device_attr_show(struct kobject *kobj,
  55                                      struct attribute *attr, char *buf)
  56 {
  57         struct acpi_device *device = to_acpi_device(kobj);
  58         struct acpi_device_attribute *attribute = to_handle_attr(attr);
  59         return attribute->show ? attribute->show(device, buf) : -EIO;
  60 }
  61 static ssize_t acpi_device_attr_store(struct kobject *kobj,
  62                                       struct attribute *attr, const char *buf,
  63                                       size_t len)
  64 {
  65         struct acpi_device *device = to_acpi_device(kobj);
  66         struct acpi_device_attribute *attribute = to_handle_attr(attr);
  67         return attribute->store ? attribute->store(device, buf, len) : -EIO;
  68 }
  69
  70 static struct sysfs_ops acpi_device_sysfs_ops = {
  71         .show = acpi_device_attr_show,
  72         .store = acpi_device_attr_store,
  73 };
  74
  75 static struct kobj_type ktype_acpi_ns = {
  76         .sysfs_ops = &acpi_device_sysfs_ops,
  77         .release = acpi_device_release,
  78 };
  79
  80 static int namespace_uevent(struct kset *kset, struct kobject *kobj,
  81                              char **envp, int num_envp, char *buffer,
  82                              int buffer_size)
  83 {
  84         struct acpi_device *dev = to_acpi_device(kobj);
  85         int i = 0;
  86         int len = 0;
  87
  88         if (!dev->driver)
  89                 return 0;
  90
  91         if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
  92                            "PHYSDEVDRIVER=%s", dev->driver->name))
  93                 return -ENOMEM;
  94
  95         envp[i] = NULL;
  96
  97         return 0;
  98 }
  99
 100 static struct kset_uevent_ops namespace_uevent_ops = {
 101         .uevent = &namespace_uevent,
 102 };
 103
 104 static struct kset acpi_namespace_kset = {
 105         .kobj = {
 106                  .name = "namespace",
 107                  },
 108         .subsys = &acpi_subsys,
 109         .ktype = &ktype_acpi_ns,
 110         .uevent_ops = &namespace_uevent_ops,
 111 };
 112
 113 static void acpi_device_register(struct acpi_device *device,
 114                                  struct acpi_device *parent)
 115 {
 116         /*
 117          * Linkage
 118          * -------
 119          * Link this device to its parent and siblings.
 120          */
 121         INIT_LIST_HEAD(&device->children);
 122         INIT_LIST_HEAD(&device->node);
 123         INIT_LIST_HEAD(&device->g_list);
 124         INIT_LIST_HEAD(&device->wakeup_list);
 125
 126         spin_lock(&acpi_device_lock);
 127         if (device->parent) {
 128                 list_add_tail(&device->node, &device->parent->children);
 129                 list_add_tail(&device->g_list, &device->parent->g_list);
 130         } else
 131                 list_add_tail(&device->g_list, &acpi_device_list);
 132         if (device->wakeup.flags.valid)
 133                 list_add_tail(&device->wakeup_list, &acpi_wakeup_device_list);
 134         spin_unlock(&acpi_device_lock);
 135
 136         strlcpy(device->kobj.name, device->pnp.bus_id, KOBJ_NAME_LEN);
 137         if (parent)
 138                 device->kobj.parent = &parent->kobj;
 139         device->kobj.ktype = &ktype_acpi_ns;
 140         device->kobj.kset = &acpi_namespace_kset;
 141         kobject_register(&device->kobj);
 142         create_sysfs_device_files(device);
 143 }
 144
 145 static void acpi_device_unregister(struct acpi_device *device, int type)
 146 {
 147         spin_lock(&acpi_device_lock);
 148         if (device->parent) {
 149                 list_del(&device->node);
 150                 list_del(&device->g_list);
 151         } else
 152                 list_del(&device->g_list);
 153
 154         list_del(&device->wakeup_list);
 155
 156         spin_unlock(&acpi_device_lock);
 157
 158         acpi_detach_data(device->handle, acpi_bus_data_handler);
 159         remove_sysfs_device_files(device);
 160         kobject_unregister(&device->kobj);
 161 }
 162
 163 void acpi_bus_data_handler(acpi_handle handle, u32 function, void *context)
 164 {
 165
 166         /* TBD */
 167
 168         return;
 169 }
 170
 171 static int acpi_bus_get_power_flags(struct acpi_device *device)
 172 {
 173         acpi_status status = 0;
 174         acpi_handle handle = NULL;
 175         u32 i = 0;
 176
 177
 178         /*
 179          * Power Management Flags
 180          */
 181         status = acpi_get_handle(device->handle, "_PSC", &handle);
 182         if (ACPI_SUCCESS(status))
 183                 device->power.flags.explicit_get = 1;
 184         status = acpi_get_handle(device->handle, "_IRC", &handle);
 185         if (ACPI_SUCCESS(status))
 186                 device->power.flags.inrush_current = 1;
 187
 188         /*
 189          * Enumerate supported power management states
 190          */
 191         for (i = ACPI_STATE_D0; i <= ACPI_STATE_D3; i++) {
 192                 struct acpi_device_power_state *ps = &device->power.states[i];
 193                 char object_name[5] = { '_', 'P', 'R', '0' + i, '\0' };
 194
 195                 /* Evaluate "_PRx" to se if power resources are referenced */
 196                 acpi_evaluate_reference(device->handle, object_name, NULL,
 197                                         &ps->resources);
 198                 if (ps->resources.count) {
 199                         device->power.flags.power_resources = 1;
 200                         ps->flags.valid = 1;
 201                 }
 202
 203                 /* Evaluate "_PSx" to see if we can do explicit sets */
 204                 object_name[2] = 'S';
 205                 status = acpi_get_handle(device->handle, object_name, &handle);
 206                 if (ACPI_SUCCESS(status)) {
 207                         ps->flags.explicit_set = 1;
 208                         ps->flags.valid = 1;
 209                 }
 210
 211                 /* State is valid if we have some power control */
 212                 if (ps->resources.count || ps->flags.explicit_set)
 213                         ps->flags.valid = 1;
 214
 215                 ps->power = -1; /* Unknown - driver assigned */
 216                 ps->latency = -1;       /* Unknown - driver assigned */
 217         }
 218
 219         /* Set defaults for D0 and D3 states (always valid) */
 220         device->power.states[ACPI_STATE_D0].flags.valid = 1;
 221         device->power.states[ACPI_STATE_D0].power = 100;
 222         device->power.states[ACPI_STATE_D3].flags.valid = 1;
 223         device->power.states[ACPI_STATE_D3].power = 0;
 224
 225         /* TBD: System wake support and resource requirements. */
 226
 227         device->power.state = ACPI_STATE_UNKNOWN;
 228
 229         return 0;
 230 }
 231
 232 int acpi_match_ids(struct acpi_device *device, char *ids)
 233 {
 234         if (device->flags.hardware_id)
 235                 if (strstr(ids, device->pnp.hardware_id))
 236                         return 0;
 237
 238         if (device->flags.compatible_ids) {
 239                 struct acpi_compatible_id_list *cid_list = device->pnp.cid_list;
 240                 int i;
 241
 242                 /* compare multiple _CID entries against driver ids */
 243                 for (i = 0; i < cid_list->count; i++) {
 244                         if (strstr(ids, cid_list->id[i].value))
 245                                 return 0;
 246                 }
 247         }
 248         return -ENOENT;
 249 }
 250
 251 static acpi_status
 252 acpi_bus_extract_wakeup_device_power_package(struct acpi_device *device,
 253                                              union acpi_object *package)
 254 {
 255         int i = 0;
 256         union acpi_object *element = NULL;
 257
 258         if (!device || !package || (package->package.count < 2))
 259                 return AE_BAD_PARAMETER;
 260
 261         element = &(package->package.elements[0]);
 262         if (!element)
 263                 return AE_BAD_PARAMETER;
 264         if (element->type == ACPI_TYPE_PACKAGE) {
 265                 if ((element->package.count < 2) ||
 266                     (element->package.elements[0].type !=
 267                      ACPI_TYPE_LOCAL_REFERENCE)
 268                     || (element->package.elements[1].type != ACPI_TYPE_INTEGER))
 269                         return AE_BAD_DATA;
 270                 device->wakeup.gpe_device =
 271                     element->package.elements[0].reference.handle;
 272                 device->wakeup.gpe_number =
 273                     (u32) element->package.elements[1].integer.value;
 274         } else if (element->type == ACPI_TYPE_INTEGER) {
 275                 device->wakeup.gpe_number = element->integer.value;
 276         } else
 277                 return AE_BAD_DATA;
 278
 279         element = &(package->package.elements[1]);
 280         if (element->type != ACPI_TYPE_INTEGER) {
 281                 return AE_BAD_DATA;
 282         }
 283         device->wakeup.sleep_state = element->integer.value;
 284
 285         if ((package->package.count - 2) > ACPI_MAX_HANDLES) {
 286                 return AE_NO_MEMORY;
 287         }
 288         device->wakeup.resources.count = package->package.count - 2;
 289         for (i = 0; i < device->wakeup.resources.count; i++) {
 290                 element = &(package->package.elements[i + 2]);
 291                 if (element->type != ACPI_TYPE_ANY) {
 292                         return AE_BAD_DATA;
 293                 }
 294
 295                 device->wakeup.resources.handles[i] = element->reference.handle;
 296         }
 297
 298         return AE_OK;
 299 }
 300
 301 static int acpi_bus_get_wakeup_device_flags(struct acpi_device *device)
 302 {
 303         acpi_status status = 0;
 304         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 305         union acpi_object *package = NULL;
 306
 307
 308         /* _PRW */
 309         status = acpi_evaluate_object(device->handle, "_PRW", NULL, &buffer);
 310         if (ACPI_FAILURE(status)) {
 311                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRW"));
 312                 goto end;
 313         }
 314
 315         package = (union acpi_object *)buffer.pointer;
 316         status = acpi_bus_extract_wakeup_device_power_package(device, package);
 317         if (ACPI_FAILURE(status)) {
 318                 ACPI_EXCEPTION((AE_INFO, status, "Extracting _PRW package"));
 319                 goto end;
 320         }
 321
 322         kfree(buffer.pointer);
 323
 324         device->wakeup.flags.valid = 1;
 325         /* Power button, Lid switch always enable wakeup */
 326         if (!acpi_match_ids(device, "PNP0C0D,PNP0C0C,PNP0C0E"))
 327                 device->wakeup.flags.run_wake = 1;
 328
 329       end:
 330         if (ACPI_FAILURE(status))
 331                 device->flags.wake_capable = 0;
 332         return 0;
 333 }
 334
 335 /* --------------------------------------------------------------------------
 336                 ACPI sysfs device file support
 337    -------------------------------------------------------------------------- */
 338 static ssize_t acpi_eject_store(struct acpi_device *device,
 339                                 const char *buf, size_t count);
 340
 341 #define ACPI_DEVICE_ATTR(_name,_mode,_show,_store) \
 342 static struct acpi_device_attribute acpi_device_attr_##_name = \
 343                 __ATTR(_name, _mode, _show, _store)
 344
 345 ACPI_DEVICE_ATTR(eject, 0200, NULL, acpi_eject_store);
 346
 347 /**
 348  * setup_sys_fs_device_files - sets up the device files under device namespace
 349  * @dev:        acpi_device object
 350  * @func:       function pointer to create or destroy the device file
 351  */
 352 static void
 353 setup_sys_fs_device_files(struct acpi_device *dev,
 354                           acpi_device_sysfs_files * func)
 355 {
 356         acpi_status status;
 357         acpi_handle temp = NULL;
 358
 359         /*
 360          * If device has _EJ0, 'eject' file is created that is used to trigger
 361          * hot-removal function from userland.
 362          */
 363         status = acpi_get_handle(dev->handle, "_EJ0", &temp);
 364         if (ACPI_SUCCESS(status))
 365                 (*(func)) (&dev->kobj, &acpi_device_attr_eject.attr);
 366 }
 367
 368 static int acpi_eject_operation(acpi_handle handle, int lockable)
 369 {
 370         struct acpi_object_list arg_list;
 371         union acpi_object arg;
 372         acpi_status status = AE_OK;
 373
 374         /*
 375          * TBD: evaluate _PS3?
 376          */
 377
 378         if (lockable) {
 379                 arg_list.count = 1;
 380                 arg_list.pointer = &arg;
 381                 arg.type = ACPI_TYPE_INTEGER;
 382                 arg.integer.value = 0;
 383                 acpi_evaluate_object(handle, "_LCK", &arg_list, NULL);
 384         }
 385
 386         arg_list.count = 1;
 387         arg_list.pointer = &arg;
 388         arg.type = ACPI_TYPE_INTEGER;
 389         arg.integer.value = 1;
 390
 391         /*
 392          * TBD: _EJD support.
 393          */
 394
 395         status = acpi_evaluate_object(handle, "_EJ0", &arg_list, NULL);
 396         if (ACPI_FAILURE(status)) {
 397                 return (-ENODEV);
 398         }
 399
 400         return (0);
 401 }
 402
 403 static ssize_t
 404 acpi_eject_store(struct acpi_device *device, const char *buf, size_t count)
 405 {
 406         int result;
 407         int ret = count;
 408         int islockable;
 409         acpi_status status;
 410         acpi_handle handle;
 411         acpi_object_type type = 0;
 412
 413         if ((!count) || (buf[0] != '1')) {
 414                 return -EINVAL;
 415         }
 416 #ifndef FORCE_EJECT
 417         if (device->driver == NULL) {
 418                 ret = -ENODEV;
 419                 goto err;
 420         }
 421 #endif
 422         status = acpi_get_type(device->handle, &type);
 423         if (ACPI_FAILURE(status) || (!device->flags.ejectable)) {
 424                 ret = -ENODEV;
 425                 goto err;
 426         }
 427
 428         islockable = device->flags.lockable;
 429         handle = device->handle;
 430
 431         result = acpi_bus_trim(device, 1);
 432
 433         if (!result)
 434                 result = acpi_eject_operation(handle, islockable);
 435
 436         if (result) {
 437                 ret = -EBUSY;
 438         }
 439       err:
 440         return ret;
 441 }
 442
 443 /* --------------------------------------------------------------------------
 444                               Performance Management
 445    -------------------------------------------------------------------------- */
 446
 447 static int acpi_bus_get_perf_flags(struct acpi_device *device)
 448 {
 449         device->performance.state = ACPI_STATE_UNKNOWN;
 450         return 0;
 451 }
 452
 453 /* --------------------------------------------------------------------------
 454                                  Driver Management
 455    -------------------------------------------------------------------------- */
 456
 457 static LIST_HEAD(acpi_bus_drivers);
 458
 459 /**
 460  * acpi_bus_match - match device IDs to driver's supported IDs
 461  * @device: the device that we are trying to match to a driver
 462  * @driver: driver whose device id table is being checked
 463  *
 464  * Checks the device's hardware (_HID) or compatible (_CID) ids to see if it
 465  * matches the specified driver's criteria.
 466  */
 467 static int
 468 acpi_bus_match(struct acpi_device *device, struct acpi_driver *driver)
 469 {
 470         if (driver && driver->ops.match)
 471                 return driver->ops.match(device, driver);
 472         return acpi_match_ids(device, driver->ids);
 473 }
 474
 475 /**
 476  * acpi_bus_driver_init - add a device to a driver
 477  * @device: the device to add and initialize
 478  * @driver: driver for the device
 479  *
 480  * Used to initialize a device via its device driver.  Called whenever a
 481  * driver is bound to a device.  Invokes the driver's add() and start() ops.
 482  */
 483 static int
 484 acpi_bus_driver_init(struct acpi_device *device, struct acpi_driver *driver)
 485 {
 486         int result = 0;
 487
 488
 489         if (!device || !driver)
 490                 return -EINVAL;
 491
 492         if (!driver->ops.add)
 493                 return -ENOSYS;
 494
 495         result = driver->ops.add(device);
 496         if (result) {
 497                 device->driver = NULL;
 498                 acpi_driver_data(device) = NULL;
 499                 return result;
 500         }
 501
 502         device->driver = driver;
 503
 504         /*
 505          * TBD - Configuration Management: Assign resources to device based
 506          * upon possible configuration and currently allocated resources.
 507          */
 508
 509         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 510                           "Driver successfully bound to device\n"));
 511         return 0;
 512 }
 513
 514 static int acpi_start_single_object(struct acpi_device *device)
 515 {
 516         int result = 0;
 517         struct acpi_driver *driver;
 518
 519
 520         if (!(driver = device->driver))
 521                 return 0;
 522
 523         if (driver->ops.start) {
 524                 result = driver->ops.start(device);
 525                 if (result && driver->ops.remove)
 526                         driver->ops.remove(device, ACPI_BUS_REMOVAL_NORMAL);
 527         }
 528
 529         return result;
 530 }
 531
 532 static void acpi_driver_attach(struct acpi_driver *drv)
 533 {
 534         struct list_head *node, *next;
 535
 536
 537         spin_lock(&acpi_device_lock);
 538         list_for_each_safe(node, next, &acpi_device_list) {
 539                 struct acpi_device *dev =
 540                     container_of(node, struct acpi_device, g_list);
 541
 542                 if (dev->driver || !dev->status.present)
 543                         continue;
 544                 spin_unlock(&acpi_device_lock);
 545
 546                 if (!acpi_bus_match(dev, drv)) {
 547                         if (!acpi_bus_driver_init(dev, drv)) {
 548                                 acpi_start_single_object(dev);
 549                                 atomic_inc(&drv->references);
 550                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 551                                                   "Found driver [%s] for device [%s]\n",
 552                                                   drv->name, dev->pnp.bus_id));
 553                         }
 554                 }
 555                 spin_lock(&acpi_device_lock);
 556         }
 557         spin_unlock(&acpi_device_lock);
 558 }
 559
 560 static void acpi_driver_detach(struct acpi_driver *drv)
 561 {
 562         struct list_head *node, *next;
 563
 564
 565         spin_lock(&acpi_device_lock);
 566         list_for_each_safe(node, next, &acpi_device_list) {
 567                 struct acpi_device *dev =
 568                     container_of(node, struct acpi_device, g_list);
 569
 570                 if (dev->driver == drv) {
 571                         spin_unlock(&acpi_device_lock);
 572                         if (drv->ops.remove)
 573                                 drv->ops.remove(dev, ACPI_BUS_REMOVAL_NORMAL);
 574                         spin_lock(&acpi_device_lock);
 575                         dev->driver = NULL;
 576                         dev->driver_data = NULL;
 577                         atomic_dec(&drv->references);
 578                 }
 579         }
 580         spin_unlock(&acpi_device_lock);
 581 }
 582
 583 /**
 584  * acpi_bus_register_driver - register a driver with the ACPI bus
 585  * @driver: driver being registered
 586  *
 587  * Registers a driver with the ACPI bus.  Searches the namespace for all
 588  * devices that match the driver's criteria and binds.  Returns zero for
 589  * success or a negative error status for failure.
 590  */
 591 int acpi_bus_register_driver(struct acpi_driver *driver)
 592 {
 593
 594         if (acpi_disabled)
 595                 return -ENODEV;
 596
 597         spin_lock(&acpi_device_lock);
 598         list_add_tail(&driver->node, &acpi_bus_drivers);
 599         spin_unlock(&acpi_device_lock);
 600         acpi_driver_attach(driver);
 601
 602         return 0;
 603 }
 604
 605 EXPORT_SYMBOL(acpi_bus_register_driver);
 606
 607 /**
 608  * acpi_bus_unregister_driver - unregisters a driver with the APIC bus
 609  * @driver: driver to unregister
 610  *
 611  * Unregisters a driver with the ACPI bus.  Searches the namespace for all
 612  * devices that match the driver's criteria and unbinds.
 613  */
 614 void acpi_bus_unregister_driver(struct acpi_driver *driver)
 615 {
 616         acpi_driver_detach(driver);
 617
 618         if (!atomic_read(&driver->references)) {
 619                 spin_lock(&acpi_device_lock);
 620                 list_del_init(&driver->node);
 621                 spin_unlock(&acpi_device_lock);
 622         }
 623         return;
 624 }
 625
 626 EXPORT_SYMBOL(acpi_bus_unregister_driver);
 627
 628 /**
 629  * acpi_bus_find_driver - check if there is a driver installed for the device
 630  * @device: device that we are trying to find a supporting driver for
 631  *
 632  * Parses the list of registered drivers looking for a driver applicable for
 633  * the specified device.
 634  */
 635 static int acpi_bus_find_driver(struct acpi_device *device)
 636 {
 637         int result = 0;
 638         struct list_head *node, *next;
 639
 640
 641         spin_lock(&acpi_device_lock);
 642         list_for_each_safe(node, next, &acpi_bus_drivers) {
 643                 struct acpi_driver *driver =
 644                     container_of(node, struct acpi_driver, node);
 645
 646                 atomic_inc(&driver->references);
 647                 spin_unlock(&acpi_device_lock);
 648                 if (!acpi_bus_match(device, driver)) {
 649                         result = acpi_bus_driver_init(device, driver);
 650                         if (!result)
 651                                 goto Done;
 652                 }
 653                 atomic_dec(&driver->references);
 654                 spin_lock(&acpi_device_lock);
 655         }
 656         spin_unlock(&acpi_device_lock);
 657
 658       Done:
 659         return result;
 660 }
 661
 662 /* --------------------------------------------------------------------------
 663                                  Device Enumeration
 664    -------------------------------------------------------------------------- */
 665
 666 static int acpi_bus_get_flags(struct acpi_device *device)
 667 {
 668         acpi_status status = AE_OK;
 669         acpi_handle temp = NULL;
 670
 671
 672         /* Presence of _STA indicates 'dynamic_status' */
 673         status = acpi_get_handle(device->handle, "_STA", &temp);
 674         if (ACPI_SUCCESS(status))
 675                 device->flags.dynamic_status = 1;
 676
 677         /* Presence of _CID indicates 'compatible_ids' */
 678         status = acpi_get_handle(device->handle, "_CID", &temp);
 679         if (ACPI_SUCCESS(status))
 680                 device->flags.compatible_ids = 1;
 681
 682         /* Presence of _RMV indicates 'removable' */
 683         status = acpi_get_handle(device->handle, "_RMV", &temp);
 684         if (ACPI_SUCCESS(status))
 685                 device->flags.removable = 1;
 686
 687         /* Presence of _EJD|_EJ0 indicates 'ejectable' */
 688         status = acpi_get_handle(device->handle, "_EJD", &temp);
 689         if (ACPI_SUCCESS(status))
 690                 device->flags.ejectable = 1;
 691         else {
 692                 status = acpi_get_handle(device->handle, "_EJ0", &temp);
 693                 if (ACPI_SUCCESS(status))
 694                         device->flags.ejectable = 1;
 695         }
 696
 697         /* Presence of _LCK indicates 'lockable' */
 698         status = acpi_get_handle(device->handle, "_LCK", &temp);
 699         if (ACPI_SUCCESS(status))
 700                 device->flags.lockable = 1;
 701
 702         /* Presence of _PS0|_PR0 indicates 'power manageable' */
 703         status = acpi_get_handle(device->handle, "_PS0", &temp);
 704         if (ACPI_FAILURE(status))
 705                 status = acpi_get_handle(device->handle, "_PR0", &temp);
 706         if (ACPI_SUCCESS(status))
 707                 device->flags.power_manageable = 1;
 708
 709         /* Presence of _PRW indicates wake capable */
 710         status = acpi_get_handle(device->handle, "_PRW", &temp);
 711         if (ACPI_SUCCESS(status))
 712                 device->flags.wake_capable = 1;
 713
 714         /* TBD: Peformance management */
 715
 716         return 0;
 717 }
 718
 719 static void acpi_device_get_busid(struct acpi_device *device,
 720                                   acpi_handle handle, int type)
 721 {
 722         char bus_id[5] = { '?', 0 };
 723         struct acpi_buffer buffer = { sizeof(bus_id), bus_id };
 724         int i = 0;
 725
 726         /*
 727          * Bus ID
 728          * ------
 729          * The device's Bus ID is simply the object name.
 730          * TBD: Shouldn't this value be unique (within the ACPI namespace)?
 731          */
 732         switch (type) {
 733         case ACPI_BUS_TYPE_SYSTEM:
 734                 strcpy(device->pnp.bus_id, "ACPI");
 735                 break;
 736         case ACPI_BUS_TYPE_POWER_BUTTON:
 737                 strcpy(device->pnp.bus_id, "PWRF");
 738                 break;
 739         case ACPI_BUS_TYPE_SLEEP_BUTTON:
 740                 strcpy(device->pnp.bus_id, "SLPF");
 741                 break;
 742         default:
 743                 acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
 744                 /* Clean up trailing underscores (if any) */
 745                 for (i = 3; i > 1; i--) {
 746                         if (bus_id[i] == '_')
 747                                 bus_id[i] = '\0';
 748                         else
 749                                 break;
 750                 }
 751                 strcpy(device->pnp.bus_id, bus_id);
 752                 break;
 753         }
 754 }
 755
 756 static void acpi_device_set_id(struct acpi_device *device,
 757                                struct acpi_device *parent, acpi_handle handle,
 758                                int type)
 759 {
 760         struct acpi_device_info *info;
 761         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 762         char *hid = NULL;
 763         char *uid = NULL;
 764         struct acpi_compatible_id_list *cid_list = NULL;
 765         acpi_status status;
 766
 767         switch (type) {
 768         case ACPI_BUS_TYPE_DEVICE:
 769                 status = acpi_get_object_info(handle, &buffer);
 770                 if (ACPI_FAILURE(status)) {
 771                         printk("%s: Error reading device info\n", __FUNCTION__);
 772                         return;
 773                 }
 774
 775                 info = buffer.pointer;
 776                 if (info->valid & ACPI_VALID_HID)
 777                         hid = info->hardware_id.value;
 778                 if (info->valid & ACPI_VALID_UID)
 779                         uid = info->unique_id.value;
 780                 if (info->valid & ACPI_VALID_CID)
 781                         cid_list = &info->compatibility_id;
 782                 if (info->valid & ACPI_VALID_ADR) {
 783                         device->pnp.bus_address = info->address;
 784                         device->flags.bus_address = 1;
 785                 }
 786                 break;
 787         case ACPI_BUS_TYPE_POWER:
 788                 hid = ACPI_POWER_HID;
 789                 break;
 790         case ACPI_BUS_TYPE_PROCESSOR:
 791                 hid = ACPI_PROCESSOR_HID;
 792                 break;
 793         case ACPI_BUS_TYPE_SYSTEM:
 794                 hid = ACPI_SYSTEM_HID;
 795                 break;
 796         case ACPI_BUS_TYPE_THERMAL:
 797                 hid = ACPI_THERMAL_HID;
 798                 break;
 799         case ACPI_BUS_TYPE_POWER_BUTTON:
 800                 hid = ACPI_BUTTON_HID_POWERF;
 801                 break;
 802         case ACPI_BUS_TYPE_SLEEP_BUTTON:
 803                 hid = ACPI_BUTTON_HID_SLEEPF;
 804                 break;
 805         }
 806
 807         /*
 808          * \_SB
 809          * ----
 810          * Fix for the system root bus device -- the only root-level device.
 811          */
 812         if (((acpi_handle)parent == ACPI_ROOT_OBJECT) && (type == ACPI_BUS_TYPE_DEVICE)) {
 813                 hid = ACPI_BUS_HID;
 814                 strcpy(device->pnp.device_name, ACPI_BUS_DEVICE_NAME);
 815                 strcpy(device->pnp.device_class, ACPI_BUS_CLASS);
 816         }
 817
 818         if (hid) {
 819                 strcpy(device->pnp.hardware_id, hid);
 820                 device->flags.hardware_id = 1;
 821         }
 822         if (uid) {
 823                 strcpy(device->pnp.unique_id, uid);
 824                 device->flags.unique_id = 1;
 825         }
 826         if (cid_list) {
 827                 device->pnp.cid_list = kmalloc(cid_list->size, GFP_KERNEL);
 828                 if (device->pnp.cid_list)
 829                         memcpy(device->pnp.cid_list, cid_list, cid_list->size);
 830                 else
 831                         printk(KERN_ERR "Memory allocation error\n");
 832         }
 833
 834         kfree(buffer.pointer);
 835 }
 836
 837 static int acpi_device_set_context(struct acpi_device *device, int type)
 838 {
 839         acpi_status status = AE_OK;
 840         int result = 0;
 841         /*
 842          * Context
 843          * -------
 844          * Attach this 'struct acpi_device' to the ACPI object.  This makes
 845          * resolutions from handle->device very efficient.  Note that we need
 846          * to be careful with fixed-feature devices as they all attach to the
 847          * root object.
 848          */
 849         if (type != ACPI_BUS_TYPE_POWER_BUTTON &&
 850             type != ACPI_BUS_TYPE_SLEEP_BUTTON) {
 851                 status = acpi_attach_data(device->handle,
 852                                           acpi_bus_data_handler, device);
 853
 854                 if (ACPI_FAILURE(status)) {
 855                         printk("Error attaching device data\n");
 856                         result = -ENODEV;
 857                 }
 858         }
 859         return result;
 860 }
 861
 862 static void acpi_device_get_debug_info(struct acpi_device *device,
 863                                        acpi_handle handle, int type)
 864 {
 865 #ifdef CONFIG_ACPI_DEBUG_OUTPUT
 866         char *type_string = NULL;
 867         char name[80] = { '?', '\0' };
 868         struct acpi_buffer buffer = { sizeof(name), name };
 869
 870         switch (type) {
 871         case ACPI_BUS_TYPE_DEVICE:
 872                 type_string = "Device";
 873                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 874                 break;
 875         case ACPI_BUS_TYPE_POWER:
 876                 type_string = "Power Resource";
 877                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 878                 break;
 879         case ACPI_BUS_TYPE_PROCESSOR:
 880                 type_string = "Processor";
 881                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 882                 break;
 883         case ACPI_BUS_TYPE_SYSTEM:
 884                 type_string = "System";
 885                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 886                 break;
 887         case ACPI_BUS_TYPE_THERMAL:
 888                 type_string = "Thermal Zone";
 889                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 890                 break;
 891         case ACPI_BUS_TYPE_POWER_BUTTON:
 892                 type_string = "Power Button";
 893                 sprintf(name, "PWRB");
 894                 break;
 895         case ACPI_BUS_TYPE_SLEEP_BUTTON:
 896                 type_string = "Sleep Button";
 897                 sprintf(name, "SLPB");
 898                 break;
 899         }
 900
 901         printk(KERN_DEBUG "Found %s %s [%p]\n", type_string, name, handle);
 902 #endif                          /*CONFIG_ACPI_DEBUG_OUTPUT */
 903 }
 904
 905 static int acpi_bus_remove(struct acpi_device *dev, int rmdevice)
 906 {
 907         int result = 0;
 908         struct acpi_driver *driver;
 909
 910
 911         if (!dev)
 912                 return -EINVAL;
 913
 914         driver = dev->driver;
 915
 916         if ((driver) && (driver->ops.remove)) {
 917
 918                 if (driver->ops.stop) {
 919                         result = driver->ops.stop(dev, ACPI_BUS_REMOVAL_EJECT);
 920                         if (result)
 921                                 return result;
 922                 }
 923
 924                 result = dev->driver->ops.remove(dev, ACPI_BUS_REMOVAL_EJECT);
 925                 if (result) {
 926                         return result;
 927                 }
 928
 929                 atomic_dec(&dev->driver->references);
 930                 dev->driver = NULL;
 931                 acpi_driver_data(dev) = NULL;
 932         }
 933
 934         if (!rmdevice)
 935                 return 0;
 936
 937         if (dev->flags.bus_address) {
 938                 if ((dev->parent) && (dev->parent->ops.unbind))
 939                         dev->parent->ops.unbind(dev);
 940         }
 941
 942         acpi_device_unregister(dev, ACPI_BUS_REMOVAL_EJECT);
 943
 944         return 0;
 945 }
 946
 947 static int
 948 acpi_add_single_object(struct acpi_device **child,
 949                        struct acpi_device *parent, acpi_handle handle, int type)
 950 {
 951         int result = 0;
 952         struct acpi_device *device = NULL;
 953
 954
 955         if (!child)
 956                 return -EINVAL;
 957
 958         device = kmalloc(sizeof(struct acpi_device), GFP_KERNEL);
 959         if (!device) {
 960                 printk(KERN_ERR PREFIX "Memory allocation error\n");
 961                 return -ENOMEM;
 962         }
 963         memset(device, 0, sizeof(struct acpi_device));
 964
 965         device->handle = handle;
 966         device->parent = parent;
 967
 968         acpi_device_get_busid(device, handle, type);
 969
 970         /*
 971          * Flags
 972          * -----
 973          * Get prior to calling acpi_bus_get_status() so we know whether
 974          * or not _STA is present.  Note that we only look for object
 975          * handles -- cannot evaluate objects until we know the device is
 976          * present and properly initialized.
 977          */
 978         result = acpi_bus_get_flags(device);
 979         if (result)
 980                 goto end;
 981
 982         /*
 983          * Status
 984          * ------
 985          * See if the device is present.  We always assume that non-Device
 986          * and non-Processor objects (e.g. thermal zones, power resources,
 987          * etc.) are present, functioning, etc. (at least when parent object
 988          * is present).  Note that _STA has a different meaning for some
 989          * objects (e.g. power resources) so we need to be careful how we use
 990          * it.
 991          */
 992         switch (type) {
 993         case ACPI_BUS_TYPE_PROCESSOR:
 994         case ACPI_BUS_TYPE_DEVICE:
 995                 result = acpi_bus_get_status(device);
 996                 if (ACPI_FAILURE(result) || !device->status.present) {
 997                         result = -ENOENT;
 998                         goto end;
 999                 }
1000                 break;
1001         default:
1002                 STRUCT_TO_INT(device->status) = 0x0F;
1003                 break;
1004         }
1005
1006         /*
1007          * Initialize Device
1008          * -----------------
1009          * TBD: Synch with Core's enumeration/initialization process.
1010          */
1011
1012         /*
1013          * Hardware ID, Unique ID, & Bus Address
1014          * -------------------------------------
1015          */
1016         acpi_device_set_id(device, parent, handle, type);
1017
1018         /*
1019          * Power Management
1020          * ----------------
1021          */
1022         if (device->flags.power_manageable) {
1023                 result = acpi_bus_get_power_flags(device);
1024                 if (result)
1025                         goto end;
1026         }
1027
1028         /*
1029          * Wakeup device management
1030          *-----------------------
1031          */
1032         if (device->flags.wake_capable) {
1033                 result = acpi_bus_get_wakeup_device_flags(device);
1034                 if (result)
1035                         goto end;
1036         }
1037
1038         /*
1039          * Performance Management
1040          * ----------------------
1041          */
1042         if (device->flags.performance_manageable) {
1043                 result = acpi_bus_get_perf_flags(device);
1044                 if (result)
1045                         goto end;
1046         }
1047
1048         if ((result = acpi_device_set_context(device, type)))
1049                 goto end;
1050
1051         acpi_device_get_debug_info(device, handle, type);
1052
1053         acpi_device_register(device, parent);
1054
1055         /*
1056          * Bind _ADR-Based Devices
1057          * -----------------------
1058          * If there's a a bus address (_ADR) then we utilize the parent's
1059          * 'bind' function (if exists) to bind the ACPI- and natively-
1060          * enumerated device representations.
1061          */
1062         if (device->flags.bus_address) {
1063                 if (device->parent && device->parent->ops.bind)
1064                         device->parent->ops.bind(device);
1065         }
1066
1067         /*
1068          * Locate & Attach Driver
1069          * ----------------------
1070          * If there's a hardware id (_HID) or compatible ids (_CID) we check
1071          * to see if there's a driver installed for this kind of device.  Note
1072          * that drivers can install before or after a device is enumerated.
1073          *
1074          * TBD: Assumes LDM provides driver hot-plug capability.
1075          */
1076         acpi_bus_find_driver(device);
1077
1078       end:
1079         if (!result)
1080                 *child = device;
1081         else {
1082                 kfree(device->pnp.cid_list);
1083                 kfree(device);
1084         }
1085
1086         return result;
1087 }
1088
1089 static int acpi_bus_scan(struct acpi_device *start, struct acpi_bus_ops *ops)
1090 {
1091         acpi_status status = AE_OK;
1092         struct acpi_device *parent = NULL;
1093         struct acpi_device *child = NULL;
1094         acpi_handle phandle = NULL;
1095         acpi_handle chandle = NULL;
1096         acpi_object_type type = 0;
1097         u32 level = 1;
1098
1099
1100         if (!start)
1101                 return -EINVAL;
1102
1103         parent = start;
1104         phandle = start->handle;
1105
1106         /*
1107          * Parse through the ACPI namespace, identify all 'devices', and
1108          * create a new 'struct acpi_device' for each.
1109          */
1110         while ((level > 0) && parent) {
1111
1112                 status = acpi_get_next_object(ACPI_TYPE_ANY, phandle,
1113                                               chandle, &chandle);
1114
1115                 /*
1116                  * If this scope is exhausted then move our way back up.
1117                  */
1118                 if (ACPI_FAILURE(status)) {
1119                         level--;
1120                         chandle = phandle;
1121                         acpi_get_parent(phandle, &phandle);
1122                         if (parent->parent)
1123                                 parent = parent->parent;
1124                         continue;
1125                 }
1126
1127                 status = acpi_get_type(chandle, &type);
1128                 if (ACPI_FAILURE(status))
1129                         continue;
1130
1131                 /*
1132                  * If this is a scope object then parse it (depth-first).
1133                  */
1134                 if (type == ACPI_TYPE_LOCAL_SCOPE) {
1135                         level++;
1136                         phandle = chandle;
1137                         chandle = NULL;
1138                         continue;
1139                 }
1140
1141                 /*
1142                  * We're only interested in objects that we consider 'devices'.
1143                  */
1144                 switch (type) {
1145                 case ACPI_TYPE_DEVICE:
1146                         type = ACPI_BUS_TYPE_DEVICE;
1147                         break;
1148                 case ACPI_TYPE_PROCESSOR:
1149                         type = ACPI_BUS_TYPE_PROCESSOR;
1150                         break;
1151                 case ACPI_TYPE_THERMAL:
1152                         type = ACPI_BUS_TYPE_THERMAL;
1153                         break;
1154                 case ACPI_TYPE_POWER:
1155                         type = ACPI_BUS_TYPE_POWER;
1156                         break;
1157                 default:
1158                         continue;
1159                 }
1160
1161                 if (ops->acpi_op_add)
1162                         status = acpi_add_single_object(&child, parent,
1163                                                         chandle, type);
1164                 else
1165                         status = acpi_bus_get_device(chandle, &child);
1166
1167                 if (ACPI_FAILURE(status))
1168                         continue;
1169
1170                 if (ops->acpi_op_start) {
1171                         status = acpi_start_single_object(child);
1172                         if (ACPI_FAILURE(status))
1173                                 continue;
1174                 }
1175
1176                 /*
1177                  * If the device is present, enabled, and functioning then
1178                  * parse its scope (depth-first).  Note that we need to
1179                  * represent absent devices to facilitate PnP notifications
1180                  * -- but only the subtree head (not all of its children,
1181                  * which will be enumerated when the parent is inserted).
1182                  *
1183                  * TBD: Need notifications and other detection mechanisms
1184                  *      in place before we can fully implement this.
1185                  */
1186                 if (child->status.present) {
1187                         status = acpi_get_next_object(ACPI_TYPE_ANY, chandle,
1188                                                       NULL, NULL);
1189                         if (ACPI_SUCCESS(status)) {
1190                                 level++;
1191                                 phandle = chandle;
1192                                 chandle = NULL;
1193                                 parent = child;
1194                         }
1195                 }
1196         }
1197
1198         return 0;
1199 }
1200
1201 int
1202 acpi_bus_add(struct acpi_device **child,
1203              struct acpi_device *parent, acpi_handle handle, int type)
1204 {
1205         int result;
1206         struct acpi_bus_ops ops;
1207
1208
1209         result = acpi_add_single_object(child, parent, handle, type);
1210         if (!result) {
1211                 memset(&ops, 0, sizeof(ops));
1212                 ops.acpi_op_add = 1;
1213                 result = acpi_bus_scan(*child, &ops);
1214         }
1215         return result;
1216 }
1217
1218 EXPORT_SYMBOL(acpi_bus_add);
1219
1220 int acpi_bus_start(struct acpi_device *device)
1221 {
1222         int result;
1223         struct acpi_bus_ops ops;
1224
1225
1226         if (!device)
1227                 return -EINVAL;
1228
1229         result = acpi_start_single_object(device);
1230         if (!result) {
1231                 memset(&ops, 0, sizeof(ops));
1232                 ops.acpi_op_start = 1;
1233                 result = acpi_bus_scan(device, &ops);
1234         }
1235         return result;
1236 }
1237
1238 EXPORT_SYMBOL(acpi_bus_start);
1239
1240 int acpi_bus_trim(struct acpi_device *start, int rmdevice)
1241 {
1242         acpi_status status;
1243         struct acpi_device *parent, *child;
1244         acpi_handle phandle, chandle;
1245         acpi_object_type type;
1246         u32 level = 1;
1247         int err = 0;
1248
1249         parent = start;
1250         phandle = start->handle;
1251         child = chandle = NULL;
1252
1253         while ((level > 0) && parent && (!err)) {
1254                 status = acpi_get_next_object(ACPI_TYPE_ANY, phandle,
1255                                               chandle, &chandle);
1256
1257                 /*
1258                  * If this scope is exhausted then move our way back up.
1259                  */
1260                 if (ACPI_FAILURE(status)) {
1261                         level--;
1262                         chandle = phandle;
1263                         acpi_get_parent(phandle, &phandle);
1264                         child = parent;
1265                         parent = parent->parent;
1266
1267                         if (level == 0)
1268                                 err = acpi_bus_remove(child, rmdevice);
1269                         else
1270                                 err = acpi_bus_remove(child, 1);
1271
1272                         continue;
1273                 }
1274
1275                 status = acpi_get_type(chandle, &type);
1276                 if (ACPI_FAILURE(status)) {
1277                         continue;
1278                 }
1279                 /*
1280                  * If there is a device corresponding to chandle then
1281                  * parse it (depth-first).
1282                  */
1283                 if (acpi_bus_get_device(chandle, &child) == 0) {
1284                         level++;
1285                         phandle = chandle;
1286                         chandle = NULL;
1287                         parent = child;
1288                 }
1289                 continue;
1290         }
1291         return err;
1292 }
1293 EXPORT_SYMBOL_GPL(acpi_bus_trim);
1294
1295
1296 static int acpi_bus_scan_fixed(struct acpi_device *root)
1297 {
1298         int result = 0;
1299         struct acpi_device *device = NULL;
1300
1301
1302         if (!root)
1303                 return -ENODEV;
1304
1305         /*
1306          * Enumerate all fixed-feature devices.
1307          */
1308         if (acpi_fadt.pwr_button == 0) {
1309                 result = acpi_add_single_object(&device, acpi_root,
1310                                                 NULL,
1311                                                 ACPI_BUS_TYPE_POWER_BUTTON);
1312                 if (!result)
1313                         result = acpi_start_single_object(device);
1314         }
1315
1316         if (acpi_fadt.sleep_button == 0) {
1317                 result = acpi_add_single_object(&device, acpi_root,
1318                                                 NULL,
1319                                                 ACPI_BUS_TYPE_SLEEP_BUTTON);
1320                 if (!result)
1321                         result = acpi_start_single_object(device);
1322         }
1323
1324         return result;
1325 }
1326
1327
1328 static inline struct acpi_device * to_acpi_dev(struct device * dev)
1329 {
1330         return container_of(dev, struct acpi_device, dev);
1331 }
1332
1333
1334 static int root_suspend(struct acpi_device * acpi_dev, pm_message_t state)
1335 {
1336         struct acpi_device * dev, * next;
1337         int result;
1338
1339         spin_lock(&acpi_device_lock);
1340         list_for_each_entry_safe_reverse(dev, next, &acpi_device_list, g_list) {
1341                 if (dev->driver && dev->driver->ops.suspend) {
1342                         spin_unlock(&acpi_device_lock);
1343                         result = dev->driver->ops.suspend(dev, 0);
1344                         if (result) {
1345                                 printk(KERN_ERR PREFIX "[%s - %s] Suspend failed: %d\n",
1346                                        acpi_device_name(dev),
1347                                        acpi_device_bid(dev), result);
1348                         }
1349                         spin_lock(&acpi_device_lock);
1350                 }
1351         }
1352         spin_unlock(&acpi_device_lock);
1353         return 0;
1354 }
1355
1356
1357 static int acpi_device_suspend(struct device * dev, pm_message_t state)
1358 {
1359         struct acpi_device * acpi_dev = to_acpi_dev(dev);
1360
1361         /*
1362          * For now, we should only register 1 generic device -
1363          * the ACPI root device - and from there, we walk the
1364          * tree of ACPI devices to suspend each one using the
1365          * ACPI driver methods.
1366          */
1367         if (acpi_dev->handle == ACPI_ROOT_OBJECT)
1368                 root_suspend(acpi_dev, state);
1369         return 0;
1370 }
1371
1372
1373
1374 static int root_resume(struct acpi_device * acpi_dev)
1375 {
1376         struct acpi_device * dev, * next;
1377         int result;
1378
1379         spin_lock(&acpi_device_lock);
1380         list_for_each_entry_safe(dev, next, &acpi_device_list, g_list) {
1381                 if (dev->driver && dev->driver->ops.resume) {
1382                         spin_unlock(&acpi_device_lock);
1383                         result = dev->driver->ops.resume(dev, 0);
1384                         if (result) {
1385                                 printk(KERN_ERR PREFIX "[%s - %s] resume failed: %d\n",
1386                                        acpi_device_name(dev),
1387                                        acpi_device_bid(dev), result);
1388                         }
1389                         spin_lock(&acpi_device_lock);
1390                 }
1391         }
1392         spin_unlock(&acpi_device_lock);
1393         return 0;
1394 }
1395
1396
1397 static int acpi_device_resume(struct device * dev)
1398 {
1399         struct acpi_device * acpi_dev = to_acpi_dev(dev);
1400
1401         /*
1402          * For now, we should only register 1 generic device -
1403          * the ACPI root device - and from there, we walk the
1404          * tree of ACPI devices to resume each one using the
1405          * ACPI driver methods.
1406          */
1407         if (acpi_dev->handle == ACPI_ROOT_OBJECT)
1408                 root_resume(acpi_dev);
1409         return 0;
1410 }
1411
1412
1413 static struct bus_type acpi_bus_type = {
1414         .name           = "acpi",
1415         .suspend        = acpi_device_suspend,
1416         .resume         = acpi_device_resume,
1417 };
1418
1419
1420
1421 static int __init acpi_scan_init(void)
1422 {
1423         int result;
1424         struct acpi_bus_ops ops;
1425
1426
1427         if (acpi_disabled)
1428                 return 0;
1429
1430         kset_register(&acpi_namespace_kset);
1431
1432         result = bus_register(&acpi_bus_type);
1433         if (result) {
1434                 /* We don't want to quit even if we failed to add suspend/resume */
1435                 printk(KERN_ERR PREFIX "Could not register bus type\n");
1436         }
1437
1438         /*
1439          * Create the root device in the bus's device tree
1440          */
1441         result = acpi_add_single_object(&acpi_root, NULL, ACPI_ROOT_OBJECT,
1442                                         ACPI_BUS_TYPE_SYSTEM);
1443         if (result)
1444                 goto Done;
1445
1446         result = acpi_start_single_object(acpi_root);
1447         if (result)
1448                 goto Done;
1449
1450         acpi_root->dev.bus = &acpi_bus_type;
1451         snprintf(acpi_root->dev.bus_id, BUS_ID_SIZE, "%s", acpi_bus_type.name);
1452         result = device_register(&acpi_root->dev);
1453         if (result) {
1454                 /* We don't want to quit even if we failed to add suspend/resume */
1455                 printk(KERN_ERR PREFIX "Could not register device\n");
1456         }
1457
1458         /*
1459          * Enumerate devices in the ACPI namespace.
1460          */
1461         result = acpi_bus_scan_fixed(acpi_root);
1462         if (!result) {
1463                 memset(&ops, 0, sizeof(ops));
1464                 ops.acpi_op_add = 1;
1465                 ops.acpi_op_start = 1;
1466                 result = acpi_bus_scan(acpi_root, &ops);
1467         }
1468
1469         if (result)
1470                 acpi_device_unregister(acpi_root, ACPI_BUS_REMOVAL_NORMAL);
1471
1472       Done:
1473         return result;
1474 }
1475
1476 subsys_initcall(acpi_scan_init);