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         if (type == ACPI_TYPE_PROCESSOR)
 445                 result = acpi_bus_trim(device, 0);
 446         else
 447                 result = acpi_bus_trim(device, 1);
 448
 449         if (!result)
 450                 result = acpi_eject_operation(handle, islockable);
 451
 452         if (result) {
 453                 ret = -EBUSY;
 454         }
 455       err:
 456         return ret;
 457 }
 458
 459 /* --------------------------------------------------------------------------
 460                               Performance Management
 461    -------------------------------------------------------------------------- */
 462
 463 static int acpi_bus_get_perf_flags(struct acpi_device *device)
 464 {
 465         device->performance.state = ACPI_STATE_UNKNOWN;
 466         return 0;
 467 }
 468
 469 /* --------------------------------------------------------------------------
 470                                  Driver Management
 471    -------------------------------------------------------------------------- */
 472
 473 static LIST_HEAD(acpi_bus_drivers);
 474 static DECLARE_MUTEX(acpi_bus_drivers_lock);
 475
 476 /**
 477  * acpi_bus_match - match device IDs to driver's supported IDs
 478  * @device: the device that we are trying to match to a driver
 479  * @driver: driver whose device id table is being checked
 480  *
 481  * Checks the device's hardware (_HID) or compatible (_CID) ids to see if it
 482  * matches the specified driver's criteria.
 483  */
 484 static int
 485 acpi_bus_match(struct acpi_device *device, struct acpi_driver *driver)
 486 {
 487         if (driver && driver->ops.match)
 488                 return driver->ops.match(device, driver);
 489         return acpi_match_ids(device, driver->ids);
 490 }
 491
 492 /**
 493  * acpi_bus_driver_init - add a device to a driver
 494  * @device: the device to add and initialize
 495  * @driver: driver for the device
 496  *
 497  * Used to initialize a device via its device driver.  Called whenever a
 498  * driver is bound to a device.  Invokes the driver's add() and start() ops.
 499  */
 500 static int
 501 acpi_bus_driver_init(struct acpi_device *device, struct acpi_driver *driver)
 502 {
 503         int result = 0;
 504
 505         ACPI_FUNCTION_TRACE("acpi_bus_driver_init");
 506
 507         if (!device || !driver)
 508                 return_VALUE(-EINVAL);
 509
 510         if (!driver->ops.add)
 511                 return_VALUE(-ENOSYS);
 512
 513         result = driver->ops.add(device);
 514         if (result) {
 515                 device->driver = NULL;
 516                 acpi_driver_data(device) = NULL;
 517                 return_VALUE(result);
 518         }
 519
 520         device->driver = driver;
 521
 522         /*
 523          * TBD - Configuration Management: Assign resources to device based
 524          * upon possible configuration and currently allocated resources.
 525          */
 526
 527         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 528                           "Driver successfully bound to device\n"));
 529         return_VALUE(0);
 530 }
 531
 532 static int acpi_start_single_object(struct acpi_device *device)
 533 {
 534         int result = 0;
 535         struct acpi_driver *driver;
 536
 537         ACPI_FUNCTION_TRACE("acpi_start_single_object");
 538
 539         if (!(driver = device->driver))
 540                 return_VALUE(0);
 541
 542         if (driver->ops.start) {
 543                 result = driver->ops.start(device);
 544                 if (result && driver->ops.remove)
 545                         driver->ops.remove(device, ACPI_BUS_REMOVAL_NORMAL);
 546         }
 547
 548         return_VALUE(result);
 549 }
 550
 551 static void acpi_driver_attach(struct acpi_driver *drv)
 552 {
 553         struct list_head *node, *next;
 554
 555         ACPI_FUNCTION_TRACE("acpi_driver_attach");
 556
 557         spin_lock(&acpi_device_lock);
 558         list_for_each_safe(node, next, &acpi_device_list) {
 559                 struct acpi_device *dev =
 560                     container_of(node, struct acpi_device, g_list);
 561
 562                 if (dev->driver || !dev->status.present)
 563                         continue;
 564                 spin_unlock(&acpi_device_lock);
 565
 566                 if (!acpi_bus_match(dev, drv)) {
 567                         if (!acpi_bus_driver_init(dev, drv)) {
 568                                 acpi_start_single_object(dev);
 569                                 atomic_inc(&drv->references);
 570                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 571                                                   "Found driver [%s] for device [%s]\n",
 572                                                   drv->name, dev->pnp.bus_id));
 573                         }
 574                 }
 575                 spin_lock(&acpi_device_lock);
 576         }
 577         spin_unlock(&acpi_device_lock);
 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 zero for
 611  * success or a negative error status for failure.
 612  */
 613 int acpi_bus_register_driver(struct acpi_driver *driver)
 614 {
 615         ACPI_FUNCTION_TRACE("acpi_bus_register_driver");
 616
 617         if (acpi_disabled)
 618                 return_VALUE(-ENODEV);
 619
 620         if (!driver)
 621                 return_VALUE(-EINVAL);
 622
 623         spin_lock(&acpi_device_lock);
 624         list_add_tail(&driver->node, &acpi_bus_drivers);
 625         spin_unlock(&acpi_device_lock);
 626         acpi_driver_attach(driver);
 627
 628         return_VALUE(0);
 629 }
 630
 631 EXPORT_SYMBOL(acpi_bus_register_driver);
 632
 633 /**
 634  * acpi_bus_unregister_driver - unregisters a driver with the APIC bus
 635  * @driver: driver to unregister
 636  *
 637  * Unregisters a driver with the ACPI bus.  Searches the namespace for all
 638  * devices that match the driver's criteria and unbinds.
 639  */
 640 int acpi_bus_unregister_driver(struct acpi_driver *driver)
 641 {
 642         int error = 0;
 643
 644         ACPI_FUNCTION_TRACE("acpi_bus_unregister_driver");
 645
 646         if (driver) {
 647                 acpi_driver_detach(driver);
 648
 649                 if (!atomic_read(&driver->references)) {
 650                         spin_lock(&acpi_device_lock);
 651                         list_del_init(&driver->node);
 652                         spin_unlock(&acpi_device_lock);
 653                 }
 654         } else
 655                 error = -EINVAL;
 656         return_VALUE(error);
 657 }
 658
 659 EXPORT_SYMBOL(acpi_bus_unregister_driver);
 660
 661 /**
 662  * acpi_bus_find_driver - check if there is a driver installed for the device
 663  * @device: device that we are trying to find a supporting driver for
 664  *
 665  * Parses the list of registered drivers looking for a driver applicable for
 666  * the specified device.
 667  */
 668 static int acpi_bus_find_driver(struct acpi_device *device)
 669 {
 670         int result = 0;
 671         struct list_head *node, *next;
 672
 673         ACPI_FUNCTION_TRACE("acpi_bus_find_driver");
 674
 675         spin_lock(&acpi_device_lock);
 676         list_for_each_safe(node, next, &acpi_bus_drivers) {
 677                 struct acpi_driver *driver =
 678                     container_of(node, struct acpi_driver, node);
 679
 680                 atomic_inc(&driver->references);
 681                 spin_unlock(&acpi_device_lock);
 682                 if (!acpi_bus_match(device, driver)) {
 683                         result = acpi_bus_driver_init(device, driver);
 684                         if (!result)
 685                                 goto Done;
 686                 }
 687                 atomic_dec(&driver->references);
 688                 spin_lock(&acpi_device_lock);
 689         }
 690         spin_unlock(&acpi_device_lock);
 691
 692       Done:
 693         return_VALUE(result);
 694 }
 695
 696 /* --------------------------------------------------------------------------
 697                                  Device Enumeration
 698    -------------------------------------------------------------------------- */
 699
 700 static int acpi_bus_get_flags(struct acpi_device *device)
 701 {
 702         acpi_status status = AE_OK;
 703         acpi_handle temp = NULL;
 704
 705         ACPI_FUNCTION_TRACE("acpi_bus_get_flags");
 706
 707         /* Presence of _STA indicates 'dynamic_status' */
 708         status = acpi_get_handle(device->handle, "_STA", &temp);
 709         if (ACPI_SUCCESS(status))
 710                 device->flags.dynamic_status = 1;
 711
 712         /* Presence of _CID indicates 'compatible_ids' */
 713         status = acpi_get_handle(device->handle, "_CID", &temp);
 714         if (ACPI_SUCCESS(status))
 715                 device->flags.compatible_ids = 1;
 716
 717         /* Presence of _RMV indicates 'removable' */
 718         status = acpi_get_handle(device->handle, "_RMV", &temp);
 719         if (ACPI_SUCCESS(status))
 720                 device->flags.removable = 1;
 721
 722         /* Presence of _EJD|_EJ0 indicates 'ejectable' */
 723         status = acpi_get_handle(device->handle, "_EJD", &temp);
 724         if (ACPI_SUCCESS(status))
 725                 device->flags.ejectable = 1;
 726         else {
 727                 status = acpi_get_handle(device->handle, "_EJ0", &temp);
 728                 if (ACPI_SUCCESS(status))
 729                         device->flags.ejectable = 1;
 730         }
 731
 732         /* Presence of _LCK indicates 'lockable' */
 733         status = acpi_get_handle(device->handle, "_LCK", &temp);
 734         if (ACPI_SUCCESS(status))
 735                 device->flags.lockable = 1;
 736
 737         /* Presence of _PS0|_PR0 indicates 'power manageable' */
 738         status = acpi_get_handle(device->handle, "_PS0", &temp);
 739         if (ACPI_FAILURE(status))
 740                 status = acpi_get_handle(device->handle, "_PR0", &temp);
 741         if (ACPI_SUCCESS(status))
 742                 device->flags.power_manageable = 1;
 743
 744         /* Presence of _PRW indicates wake capable */
 745         status = acpi_get_handle(device->handle, "_PRW", &temp);
 746         if (ACPI_SUCCESS(status))
 747                 device->flags.wake_capable = 1;
 748
 749         /* TBD: Peformance management */
 750
 751         return_VALUE(0);
 752 }
 753
 754 static void acpi_device_get_busid(struct acpi_device *device,
 755                                   acpi_handle handle, int type)
 756 {
 757         char bus_id[5] = { '?', 0 };
 758         struct acpi_buffer buffer = { sizeof(bus_id), bus_id };
 759         int i = 0;
 760
 761         /*
 762          * Bus ID
 763          * ------
 764          * The device's Bus ID is simply the object name.
 765          * TBD: Shouldn't this value be unique (within the ACPI namespace)?
 766          */
 767         switch (type) {
 768         case ACPI_BUS_TYPE_SYSTEM:
 769                 strcpy(device->pnp.bus_id, "ACPI");
 770                 break;
 771         case ACPI_BUS_TYPE_POWER_BUTTON:
 772                 strcpy(device->pnp.bus_id, "PWRF");
 773                 break;
 774         case ACPI_BUS_TYPE_SLEEP_BUTTON:
 775                 strcpy(device->pnp.bus_id, "SLPF");
 776                 break;
 777         default:
 778                 acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
 779                 /* Clean up trailing underscores (if any) */
 780                 for (i = 3; i > 1; i--) {
 781                         if (bus_id[i] == '_')
 782                                 bus_id[i] = '\0';
 783                         else
 784                                 break;
 785                 }
 786                 strcpy(device->pnp.bus_id, bus_id);
 787                 break;
 788         }
 789 }
 790
 791 static void acpi_device_set_id(struct acpi_device *device,
 792                                struct acpi_device *parent, acpi_handle handle,
 793                                int type)
 794 {
 795         struct acpi_device_info *info;
 796         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 797         char *hid = NULL;
 798         char *uid = NULL;
 799         struct acpi_compatible_id_list *cid_list = NULL;
 800         acpi_status status;
 801
 802         switch (type) {
 803         case ACPI_BUS_TYPE_DEVICE:
 804                 status = acpi_get_object_info(handle, &buffer);
 805                 if (ACPI_FAILURE(status)) {
 806                         printk("%s: Error reading device info\n", __FUNCTION__);
 807                         return;
 808                 }
 809
 810                 info = buffer.pointer;
 811                 if (info->valid & ACPI_VALID_HID)
 812                         hid = info->hardware_id.value;
 813                 if (info->valid & ACPI_VALID_UID)
 814                         uid = info->unique_id.value;
 815                 if (info->valid & ACPI_VALID_CID)
 816                         cid_list = &info->compatibility_id;
 817                 if (info->valid & ACPI_VALID_ADR) {
 818                         device->pnp.bus_address = info->address;
 819                         device->flags.bus_address = 1;
 820                 }
 821                 break;
 822         case ACPI_BUS_TYPE_POWER:
 823                 hid = ACPI_POWER_HID;
 824                 break;
 825         case ACPI_BUS_TYPE_PROCESSOR:
 826                 hid = ACPI_PROCESSOR_HID;
 827                 break;
 828         case ACPI_BUS_TYPE_SYSTEM:
 829                 hid = ACPI_SYSTEM_HID;
 830                 break;
 831         case ACPI_BUS_TYPE_THERMAL:
 832                 hid = ACPI_THERMAL_HID;
 833                 break;
 834         case ACPI_BUS_TYPE_POWER_BUTTON:
 835                 hid = ACPI_BUTTON_HID_POWERF;
 836                 break;
 837         case ACPI_BUS_TYPE_SLEEP_BUTTON:
 838                 hid = ACPI_BUTTON_HID_SLEEPF;
 839                 break;
 840         }
 841
 842         /*
 843          * \_SB
 844          * ----
 845          * Fix for the system root bus device -- the only root-level device.
 846          */
 847         if (((acpi_handle)parent == ACPI_ROOT_OBJECT) && (type == ACPI_BUS_TYPE_DEVICE)) {
 848                 hid = ACPI_BUS_HID;
 849                 strcpy(device->pnp.device_name, ACPI_BUS_DEVICE_NAME);
 850                 strcpy(device->pnp.device_class, ACPI_BUS_CLASS);
 851         }
 852
 853         if (hid) {
 854                 strcpy(device->pnp.hardware_id, hid);
 855                 device->flags.hardware_id = 1;
 856         }
 857         if (uid) {
 858                 strcpy(device->pnp.unique_id, uid);
 859                 device->flags.unique_id = 1;
 860         }
 861         if (cid_list) {
 862                 device->pnp.cid_list = kmalloc(cid_list->size, GFP_KERNEL);
 863                 if (device->pnp.cid_list)
 864                         memcpy(device->pnp.cid_list, cid_list, cid_list->size);
 865                 else
 866                         printk(KERN_ERR "Memory allocation error\n");
 867         }
 868
 869         acpi_os_free(buffer.pointer);
 870 }
 871
 872 static int acpi_device_set_context(struct acpi_device *device, int type)
 873 {
 874         acpi_status status = AE_OK;
 875         int result = 0;
 876         /*
 877          * Context
 878          * -------
 879          * Attach this 'struct acpi_device' to the ACPI object.  This makes
 880          * resolutions from handle->device very efficient.  Note that we need
 881          * to be careful with fixed-feature devices as they all attach to the
 882          * root object.
 883          */
 884         if (type != ACPI_BUS_TYPE_POWER_BUTTON &&
 885             type != ACPI_BUS_TYPE_SLEEP_BUTTON) {
 886                 status = acpi_attach_data(device->handle,
 887                                           acpi_bus_data_handler, device);
 888
 889                 if (ACPI_FAILURE(status)) {
 890                         printk("Error attaching device data\n");
 891                         result = -ENODEV;
 892                 }
 893         }
 894         return result;
 895 }
 896
 897 static void acpi_device_get_debug_info(struct acpi_device *device,
 898                                        acpi_handle handle, int type)
 899 {
 900 #ifdef CONFIG_ACPI_DEBUG_OUTPUT
 901         char *type_string = NULL;
 902         char name[80] = { '?', '\0' };
 903         struct acpi_buffer buffer = { sizeof(name), name };
 904
 905         switch (type) {
 906         case ACPI_BUS_TYPE_DEVICE:
 907                 type_string = "Device";
 908                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 909                 break;
 910         case ACPI_BUS_TYPE_POWER:
 911                 type_string = "Power Resource";
 912                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 913                 break;
 914         case ACPI_BUS_TYPE_PROCESSOR:
 915                 type_string = "Processor";
 916                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 917                 break;
 918         case ACPI_BUS_TYPE_SYSTEM:
 919                 type_string = "System";
 920                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 921                 break;
 922         case ACPI_BUS_TYPE_THERMAL:
 923                 type_string = "Thermal Zone";
 924                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 925                 break;
 926         case ACPI_BUS_TYPE_POWER_BUTTON:
 927                 type_string = "Power Button";
 928                 sprintf(name, "PWRB");
 929                 break;
 930         case ACPI_BUS_TYPE_SLEEP_BUTTON:
 931                 type_string = "Sleep Button";
 932                 sprintf(name, "SLPB");
 933                 break;
 934         }
 935
 936         printk(KERN_DEBUG "Found %s %s [%p]\n", type_string, name, handle);
 937 #endif                          /*CONFIG_ACPI_DEBUG_OUTPUT */
 938 }
 939
 940 static int acpi_bus_remove(struct acpi_device *dev, int rmdevice)
 941 {
 942         int result = 0;
 943         struct acpi_driver *driver;
 944
 945         ACPI_FUNCTION_TRACE("acpi_bus_remove");
 946
 947         if (!dev)
 948                 return_VALUE(-EINVAL);
 949
 950         driver = dev->driver;
 951
 952         if ((driver) && (driver->ops.remove)) {
 953
 954                 if (driver->ops.stop) {
 955                         result = driver->ops.stop(dev, ACPI_BUS_REMOVAL_EJECT);
 956                         if (result)
 957                                 return_VALUE(result);
 958                 }
 959
 960                 result = dev->driver->ops.remove(dev, ACPI_BUS_REMOVAL_EJECT);
 961                 if (result) {
 962                         return_VALUE(result);
 963                 }
 964
 965                 atomic_dec(&dev->driver->references);
 966                 dev->driver = NULL;
 967                 acpi_driver_data(dev) = NULL;
 968         }
 969
 970         if (!rmdevice)
 971                 return_VALUE(0);
 972
 973         if (dev->flags.bus_address) {
 974                 if ((dev->parent) && (dev->parent->ops.unbind))
 975                         dev->parent->ops.unbind(dev);
 976         }
 977
 978         acpi_device_unregister(dev, ACPI_BUS_REMOVAL_EJECT);
 979
 980         return_VALUE(0);
 981 }
 982
 983 static int
 984 acpi_add_single_object(struct acpi_device **child,
 985                        struct acpi_device *parent, acpi_handle handle, int type)
 986 {
 987         int result = 0;
 988         struct acpi_device *device = NULL;
 989
 990         ACPI_FUNCTION_TRACE("acpi_add_single_object");
 991
 992         if (!child)
 993                 return_VALUE(-EINVAL);
 994
 995         device = kmalloc(sizeof(struct acpi_device), GFP_KERNEL);
 996         if (!device) {
 997                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Memory allocation error\n"));
 998                 return_VALUE(-ENOMEM);
 999         }
1000         memset(device, 0, sizeof(struct acpi_device));
1001
1002         device->handle = handle;
1003         device->parent = parent;
1004
1005         acpi_device_get_busid(device, handle, type);
1006
1007         /*
1008          * Flags
1009          * -----
1010          * Get prior to calling acpi_bus_get_status() so we know whether
1011          * or not _STA is present.  Note that we only look for object
1012          * handles -- cannot evaluate objects until we know the device is
1013          * present and properly initialized.
1014          */
1015         result = acpi_bus_get_flags(device);
1016         if (result)
1017                 goto end;
1018
1019         /*
1020          * Status
1021          * ------
1022          * See if the device is present.  We always assume that non-Device
1023          * and non-Processor objects (e.g. thermal zones, power resources,
1024          * etc.) are present, functioning, etc. (at least when parent object
1025          * is present).  Note that _STA has a different meaning for some
1026          * objects (e.g. power resources) so we need to be careful how we use
1027          * it.
1028          */
1029         switch (type) {
1030         case ACPI_BUS_TYPE_PROCESSOR:
1031         case ACPI_BUS_TYPE_DEVICE:
1032                 result = acpi_bus_get_status(device);
1033                 if (ACPI_FAILURE(result) || !device->status.present) {
1034                         result = -ENOENT;
1035                         goto end;
1036                 }
1037                 break;
1038         default:
1039                 STRUCT_TO_INT(device->status) = 0x0F;
1040                 break;
1041         }
1042
1043         /*
1044          * Initialize Device
1045          * -----------------
1046          * TBD: Synch with Core's enumeration/initialization process.
1047          */
1048
1049         /*
1050          * Hardware ID, Unique ID, & Bus Address
1051          * -------------------------------------
1052          */
1053         acpi_device_set_id(device, parent, handle, type);
1054
1055         /*
1056          * Power Management
1057          * ----------------
1058          */
1059         if (device->flags.power_manageable) {
1060                 result = acpi_bus_get_power_flags(device);
1061                 if (result)
1062                         goto end;
1063         }
1064
1065         /*
1066          * Wakeup device management
1067          *-----------------------
1068          */
1069         if (device->flags.wake_capable) {
1070                 result = acpi_bus_get_wakeup_device_flags(device);
1071                 if (result)
1072                         goto end;
1073         }
1074
1075         /*
1076          * Performance Management
1077          * ----------------------
1078          */
1079         if (device->flags.performance_manageable) {
1080                 result = acpi_bus_get_perf_flags(device);
1081                 if (result)
1082                         goto end;
1083         }
1084
1085         if ((result = acpi_device_set_context(device, type)))
1086                 goto end;
1087
1088         acpi_device_get_debug_info(device, handle, type);
1089
1090         acpi_device_register(device, parent);
1091
1092         /*
1093          * Bind _ADR-Based Devices
1094          * -----------------------
1095          * If there's a a bus address (_ADR) then we utilize the parent's
1096          * 'bind' function (if exists) to bind the ACPI- and natively-
1097          * enumerated device representations.
1098          */
1099         if (device->flags.bus_address) {
1100                 if (device->parent && device->parent->ops.bind)
1101                         device->parent->ops.bind(device);
1102         }
1103
1104         /*
1105          * Locate & Attach Driver
1106          * ----------------------
1107          * If there's a hardware id (_HID) or compatible ids (_CID) we check
1108          * to see if there's a driver installed for this kind of device.  Note
1109          * that drivers can install before or after a device is enumerated.
1110          *
1111          * TBD: Assumes LDM provides driver hot-plug capability.
1112          */
1113         acpi_bus_find_driver(device);
1114
1115       end:
1116         if (!result)
1117                 *child = device;
1118         else {
1119                 kfree(device->pnp.cid_list);
1120                 kfree(device);
1121         }
1122
1123         return_VALUE(result);
1124 }
1125
1126 static int acpi_bus_scan(struct acpi_device *start, struct acpi_bus_ops *ops)
1127 {
1128         acpi_status status = AE_OK;
1129         struct acpi_device *parent = NULL;
1130         struct acpi_device *child = NULL;
1131         acpi_handle phandle = NULL;
1132         acpi_handle chandle = NULL;
1133         acpi_object_type type = 0;
1134         u32 level = 1;
1135
1136         ACPI_FUNCTION_TRACE("acpi_bus_scan");
1137
1138         if (!start)
1139                 return_VALUE(-EINVAL);
1140
1141         parent = start;
1142         phandle = start->handle;
1143
1144         /*
1145          * Parse through the ACPI namespace, identify all 'devices', and
1146          * create a new 'struct acpi_device' for each.
1147          */
1148         while ((level > 0) && parent) {
1149
1150                 status = acpi_get_next_object(ACPI_TYPE_ANY, phandle,
1151                                               chandle, &chandle);
1152
1153                 /*
1154                  * If this scope is exhausted then move our way back up.
1155                  */
1156                 if (ACPI_FAILURE(status)) {
1157                         level--;
1158                         chandle = phandle;
1159                         acpi_get_parent(phandle, &phandle);
1160                         if (parent->parent)
1161                                 parent = parent->parent;
1162                         continue;
1163                 }
1164
1165                 status = acpi_get_type(chandle, &type);
1166                 if (ACPI_FAILURE(status))
1167                         continue;
1168
1169                 /*
1170                  * If this is a scope object then parse it (depth-first).
1171                  */
1172                 if (type == ACPI_TYPE_LOCAL_SCOPE) {
1173                         level++;
1174                         phandle = chandle;
1175                         chandle = NULL;
1176                         continue;
1177                 }
1178
1179                 /*
1180                  * We're only interested in objects that we consider 'devices'.
1181                  */
1182                 switch (type) {
1183                 case ACPI_TYPE_DEVICE:
1184                         type = ACPI_BUS_TYPE_DEVICE;
1185                         break;
1186                 case ACPI_TYPE_PROCESSOR:
1187                         type = ACPI_BUS_TYPE_PROCESSOR;
1188                         break;
1189                 case ACPI_TYPE_THERMAL:
1190                         type = ACPI_BUS_TYPE_THERMAL;
1191                         break;
1192                 case ACPI_TYPE_POWER:
1193                         type = ACPI_BUS_TYPE_POWER;
1194                         break;
1195                 default:
1196                         continue;
1197                 }
1198
1199                 if (ops->acpi_op_add)
1200                         status = acpi_add_single_object(&child, parent,
1201                                                         chandle, type);
1202                 else
1203                         status = acpi_bus_get_device(chandle, &child);
1204
1205                 if (ACPI_FAILURE(status))
1206                         continue;
1207
1208                 if (ops->acpi_op_start) {
1209                         status = acpi_start_single_object(child);
1210                         if (ACPI_FAILURE(status))
1211                                 continue;
1212                 }
1213
1214                 /*
1215                  * If the device is present, enabled, and functioning then
1216                  * parse its scope (depth-first).  Note that we need to
1217                  * represent absent devices to facilitate PnP notifications
1218                  * -- but only the subtree head (not all of its children,
1219                  * which will be enumerated when the parent is inserted).
1220                  *
1221                  * TBD: Need notifications and other detection mechanisms
1222                  *      in place before we can fully implement this.
1223                  */
1224                 if (child->status.present) {
1225                         status = acpi_get_next_object(ACPI_TYPE_ANY, chandle,
1226                                                       NULL, NULL);
1227                         if (ACPI_SUCCESS(status)) {
1228                                 level++;
1229                                 phandle = chandle;
1230                                 chandle = NULL;
1231                                 parent = child;
1232                         }
1233                 }
1234         }
1235
1236         return_VALUE(0);
1237 }
1238
1239 int
1240 acpi_bus_add(struct acpi_device **child,
1241              struct acpi_device *parent, acpi_handle handle, int type)
1242 {
1243         int result;
1244         struct acpi_bus_ops ops;
1245
1246         ACPI_FUNCTION_TRACE("acpi_bus_add");
1247
1248         result = acpi_add_single_object(child, parent, handle, type);
1249         if (!result) {
1250                 memset(&ops, 0, sizeof(ops));
1251                 ops.acpi_op_add = 1;
1252                 result = acpi_bus_scan(*child, &ops);
1253         }
1254         return_VALUE(result);
1255 }
1256
1257 EXPORT_SYMBOL(acpi_bus_add);
1258
1259 int acpi_bus_start(struct acpi_device *device)
1260 {
1261         int result;
1262         struct acpi_bus_ops ops;
1263
1264         ACPI_FUNCTION_TRACE("acpi_bus_start");
1265
1266         if (!device)
1267                 return_VALUE(-EINVAL);
1268
1269         result = acpi_start_single_object(device);
1270         if (!result) {
1271                 memset(&ops, 0, sizeof(ops));
1272                 ops.acpi_op_start = 1;
1273                 result = acpi_bus_scan(device, &ops);
1274         }
1275         return_VALUE(result);
1276 }
1277
1278 EXPORT_SYMBOL(acpi_bus_start);
1279
1280 int acpi_bus_trim(struct acpi_device *start, int rmdevice)
1281 {
1282         acpi_status status;
1283         struct acpi_device *parent, *child;
1284         acpi_handle phandle, chandle;
1285         acpi_object_type type;
1286         u32 level = 1;
1287         int err = 0;
1288
1289         parent = start;
1290         phandle = start->handle;
1291         child = chandle = NULL;
1292
1293         while ((level > 0) && parent && (!err)) {
1294                 status = acpi_get_next_object(ACPI_TYPE_ANY, phandle,
1295                                               chandle, &chandle);
1296
1297                 /*
1298                  * If this scope is exhausted then move our way back up.
1299                  */
1300                 if (ACPI_FAILURE(status)) {
1301                         level--;
1302                         chandle = phandle;
1303                         acpi_get_parent(phandle, &phandle);
1304                         child = parent;
1305                         parent = parent->parent;
1306
1307                         if (level == 0)
1308                                 err = acpi_bus_remove(child, rmdevice);
1309                         else
1310                                 err = acpi_bus_remove(child, 1);
1311
1312                         continue;
1313                 }
1314
1315                 status = acpi_get_type(chandle, &type);
1316                 if (ACPI_FAILURE(status)) {
1317                         continue;
1318                 }
1319                 /*
1320                  * If there is a device corresponding to chandle then
1321                  * parse it (depth-first).
1322                  */
1323                 if (acpi_bus_get_device(chandle, &child) == 0) {
1324                         level++;
1325                         phandle = chandle;
1326                         chandle = NULL;
1327                         parent = child;
1328                 }
1329                 continue;
1330         }
1331         return err;
1332 }
1333 EXPORT_SYMBOL_GPL(acpi_bus_trim);
1334
1335
1336 static int acpi_bus_scan_fixed(struct acpi_device *root)
1337 {
1338         int result = 0;
1339         struct acpi_device *device = NULL;
1340
1341         ACPI_FUNCTION_TRACE("acpi_bus_scan_fixed");
1342
1343         if (!root)
1344                 return_VALUE(-ENODEV);
1345
1346         /*
1347          * Enumerate all fixed-feature devices.
1348          */
1349         if (acpi_fadt.pwr_button == 0) {
1350                 result = acpi_add_single_object(&device, acpi_root,
1351                                                 NULL,
1352                                                 ACPI_BUS_TYPE_POWER_BUTTON);
1353                 if (!result)
1354                         result = acpi_start_single_object(device);
1355         }
1356
1357         if (acpi_fadt.sleep_button == 0) {
1358                 result = acpi_add_single_object(&device, acpi_root,
1359                                                 NULL,
1360                                                 ACPI_BUS_TYPE_SLEEP_BUTTON);
1361                 if (!result)
1362                         result = acpi_start_single_object(device);
1363         }
1364
1365         return_VALUE(result);
1366 }
1367
1368 static int __init acpi_scan_init(void)
1369 {
1370         int result;
1371         struct acpi_bus_ops ops;
1372
1373         ACPI_FUNCTION_TRACE("acpi_scan_init");
1374
1375         if (acpi_disabled)
1376                 return_VALUE(0);
1377
1378         kset_register(&acpi_namespace_kset);
1379
1380         /*
1381          * Create the root device in the bus's device tree
1382          */
1383         result = acpi_add_single_object(&acpi_root, NULL, ACPI_ROOT_OBJECT,
1384                                         ACPI_BUS_TYPE_SYSTEM);
1385         if (result)
1386                 goto Done;
1387
1388         result = acpi_start_single_object(acpi_root);
1389
1390         /*
1391          * Enumerate devices in the ACPI namespace.
1392          */
1393         result = acpi_bus_scan_fixed(acpi_root);
1394         if (!result) {
1395                 memset(&ops, 0, sizeof(ops));
1396                 ops.acpi_op_add = 1;
1397                 ops.acpi_op_start = 1;
1398                 result = acpi_bus_scan(acpi_root, &ops);
1399         }
1400
1401         if (result)
1402                 acpi_device_unregister(acpi_root, ACPI_BUS_REMOVAL_NORMAL);
1403
1404       Done:
1405         return_VALUE(result);
1406 }
1407
1408 subsys_initcall(acpi_scan_init);