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