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