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