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
 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 int acpi_driver_attach(struct acpi_driver *drv)
 551 {
 552         struct list_head *node, *next;
 553         int count = 0;
 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                                 count++;
 571                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 572                                                   "Found driver [%s] for device [%s]\n",
 573                                                   drv->name, dev->pnp.bus_id));
 574                         }
 575                 }
 576                 spin_lock(&acpi_device_lock);
 577         }
 578         spin_unlock(&acpi_device_lock);
 579         return_VALUE(count);
 580 }
 581
 582 static int acpi_driver_detach(struct acpi_driver *drv)
 583 {
 584         struct list_head *node, *next;
 585
 586         ACPI_FUNCTION_TRACE("acpi_driver_detach");
 587
 588         spin_lock(&acpi_device_lock);
 589         list_for_each_safe(node, next, &acpi_device_list) {
 590                 struct acpi_device *dev =
 591                     container_of(node, struct acpi_device, g_list);
 592
 593                 if (dev->driver == drv) {
 594                         spin_unlock(&acpi_device_lock);
 595                         if (drv->ops.remove)
 596                                 drv->ops.remove(dev, ACPI_BUS_REMOVAL_NORMAL);
 597                         spin_lock(&acpi_device_lock);
 598                         dev->driver = NULL;
 599                         dev->driver_data = NULL;
 600                         atomic_dec(&drv->references);
 601                 }
 602         }
 603         spin_unlock(&acpi_device_lock);
 604         return_VALUE(0);
 605 }
 606
 607 /**
 608  * acpi_bus_register_driver - register a driver with the ACPI bus
 609  * @driver: driver being registered
 610  *
 611  * Registers a driver with the ACPI bus.  Searches the namespace for all
 612  * devices that match the driver's criteria and binds.  Returns the
 613  * number of devices that were claimed by the driver, or a negative
 614  * error status for failure.
 615  */
 616 int acpi_bus_register_driver(struct acpi_driver *driver)
 617 {
 618         int count;
 619
 620         ACPI_FUNCTION_TRACE("acpi_bus_register_driver");
 621
 622         if (acpi_disabled)
 623                 return_VALUE(-ENODEV);
 624
 625         if (!driver)
 626                 return_VALUE(-EINVAL);
 627
 628         spin_lock(&acpi_device_lock);
 629         list_add_tail(&driver->node, &acpi_bus_drivers);
 630         spin_unlock(&acpi_device_lock);
 631         count = acpi_driver_attach(driver);
 632
 633         return_VALUE(count);
 634 }
 635
 636 EXPORT_SYMBOL(acpi_bus_register_driver);
 637
 638 /**
 639  * acpi_bus_unregister_driver - unregisters a driver with the APIC bus
 640  * @driver: driver to unregister
 641  *
 642  * Unregisters a driver with the ACPI bus.  Searches the namespace for all
 643  * devices that match the driver's criteria and unbinds.
 644  */
 645 int acpi_bus_unregister_driver(struct acpi_driver *driver)
 646 {
 647         int error = 0;
 648
 649         ACPI_FUNCTION_TRACE("acpi_bus_unregister_driver");
 650
 651         if (driver) {
 652                 acpi_driver_detach(driver);
 653
 654                 if (!atomic_read(&driver->references)) {
 655                         spin_lock(&acpi_device_lock);
 656                         list_del_init(&driver->node);
 657                         spin_unlock(&acpi_device_lock);
 658                 }
 659         } else
 660                 error = -EINVAL;
 661         return_VALUE(error);
 662 }
 663
 664 EXPORT_SYMBOL(acpi_bus_unregister_driver);
 665
 666 /**
 667  * acpi_bus_find_driver - check if there is a driver installed for the device
 668  * @device: device that we are trying to find a supporting driver for
 669  *
 670  * Parses the list of registered drivers looking for a driver applicable for
 671  * the specified device.
 672  */
 673 static int acpi_bus_find_driver(struct acpi_device *device)
 674 {
 675         int result = 0;
 676         struct list_head *node, *next;
 677
 678         ACPI_FUNCTION_TRACE("acpi_bus_find_driver");
 679
 680         spin_lock(&acpi_device_lock);
 681         list_for_each_safe(node, next, &acpi_bus_drivers) {
 682                 struct acpi_driver *driver =
 683                     container_of(node, struct acpi_driver, node);
 684
 685                 atomic_inc(&driver->references);
 686                 spin_unlock(&acpi_device_lock);
 687                 if (!acpi_bus_match(device, driver)) {
 688                         result = acpi_bus_driver_init(device, driver);
 689                         if (!result)
 690                                 goto Done;
 691                 }
 692                 atomic_dec(&driver->references);
 693                 spin_lock(&acpi_device_lock);
 694         }
 695         spin_unlock(&acpi_device_lock);
 696
 697       Done:
 698         return_VALUE(result);
 699 }
 700
 701 /* --------------------------------------------------------------------------
 702                                  Device Enumeration
 703    -------------------------------------------------------------------------- */
 704
 705 static int acpi_bus_get_flags(struct acpi_device *device)
 706 {
 707         acpi_status status = AE_OK;
 708         acpi_handle temp = NULL;
 709
 710         ACPI_FUNCTION_TRACE("acpi_bus_get_flags");
 711
 712         /* Presence of _STA indicates 'dynamic_status' */
 713         status = acpi_get_handle(device->handle, "_STA", &temp);
 714         if (ACPI_SUCCESS(status))
 715                 device->flags.dynamic_status = 1;
 716
 717         /* Presence of _CID indicates 'compatible_ids' */
 718         status = acpi_get_handle(device->handle, "_CID", &temp);
 719         if (ACPI_SUCCESS(status))
 720                 device->flags.compatible_ids = 1;
 721
 722         /* Presence of _RMV indicates 'removable' */
 723         status = acpi_get_handle(device->handle, "_RMV", &temp);
 724         if (ACPI_SUCCESS(status))
 725                 device->flags.removable = 1;
 726
 727         /* Presence of _EJD|_EJ0 indicates 'ejectable' */
 728         status = acpi_get_handle(device->handle, "_EJD", &temp);
 729         if (ACPI_SUCCESS(status))
 730                 device->flags.ejectable = 1;
 731         else {
 732                 status = acpi_get_handle(device->handle, "_EJ0", &temp);
 733                 if (ACPI_SUCCESS(status))
 734                         device->flags.ejectable = 1;
 735         }
 736
 737         /* Presence of _LCK indicates 'lockable' */
 738         status = acpi_get_handle(device->handle, "_LCK", &temp);
 739         if (ACPI_SUCCESS(status))
 740                 device->flags.lockable = 1;
 741
 742         /* Presence of _PS0|_PR0 indicates 'power manageable' */
 743         status = acpi_get_handle(device->handle, "_PS0", &temp);
 744         if (ACPI_FAILURE(status))
 745                 status = acpi_get_handle(device->handle, "_PR0", &temp);
 746         if (ACPI_SUCCESS(status))
 747                 device->flags.power_manageable = 1;
 748
 749         /* Presence of _PRW indicates wake capable */
 750         status = acpi_get_handle(device->handle, "_PRW", &temp);
 751         if (ACPI_SUCCESS(status))
 752                 device->flags.wake_capable = 1;
 753
 754         /* TBD: Peformance management */
 755
 756         return_VALUE(0);
 757 }
 758
 759 static void acpi_device_get_busid(struct acpi_device *device,
 760                                   acpi_handle handle, int type)
 761 {
 762         char bus_id[5] = { '?', 0 };
 763         struct acpi_buffer buffer = { sizeof(bus_id), bus_id };
 764         int i = 0;
 765
 766         /*
 767          * Bus ID
 768          * ------
 769          * The device's Bus ID is simply the object name.
 770          * TBD: Shouldn't this value be unique (within the ACPI namespace)?
 771          */
 772         switch (type) {
 773         case ACPI_BUS_TYPE_SYSTEM:
 774                 strcpy(device->pnp.bus_id, "ACPI");
 775                 break;
 776         case ACPI_BUS_TYPE_POWER_BUTTON:
 777                 strcpy(device->pnp.bus_id, "PWRF");
 778                 break;
 779         case ACPI_BUS_TYPE_SLEEP_BUTTON:
 780                 strcpy(device->pnp.bus_id, "SLPF");
 781                 break;
 782         default:
 783                 acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
 784                 /* Clean up trailing underscores (if any) */
 785                 for (i = 3; i > 1; i--) {
 786                         if (bus_id[i] == '_')
 787                                 bus_id[i] = '\0';
 788                         else
 789                                 break;
 790                 }
 791                 strcpy(device->pnp.bus_id, bus_id);
 792                 break;
 793         }
 794 }
 795
 796 static void acpi_device_set_id(struct acpi_device *device,
 797                                struct acpi_device *parent, acpi_handle handle,
 798                                int type)
 799 {
 800         struct acpi_device_info *info;
 801         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 802         char *hid = NULL;
 803         char *uid = NULL;
 804         struct acpi_compatible_id_list *cid_list = NULL;
 805         acpi_status status;
 806
 807         switch (type) {
 808         case ACPI_BUS_TYPE_DEVICE:
 809                 status = acpi_get_object_info(handle, &buffer);
 810                 if (ACPI_FAILURE(status)) {
 811                         printk("%s: Error reading device info\n", __FUNCTION__);
 812                         return;
 813                 }
 814
 815                 info = buffer.pointer;
 816                 if (info->valid & ACPI_VALID_HID)
 817                         hid = info->hardware_id.value;
 818                 if (info->valid & ACPI_VALID_UID)
 819                         uid = info->unique_id.value;
 820                 if (info->valid & ACPI_VALID_CID)
 821                         cid_list = &info->compatibility_id;
 822                 if (info->valid & ACPI_VALID_ADR) {
 823                         device->pnp.bus_address = info->address;
 824                         device->flags.bus_address = 1;
 825                 }
 826                 break;
 827         case ACPI_BUS_TYPE_POWER:
 828                 hid = ACPI_POWER_HID;
 829                 break;
 830         case ACPI_BUS_TYPE_PROCESSOR:
 831                 hid = ACPI_PROCESSOR_HID;
 832                 break;
 833         case ACPI_BUS_TYPE_SYSTEM:
 834                 hid = ACPI_SYSTEM_HID;
 835                 break;
 836         case ACPI_BUS_TYPE_THERMAL:
 837                 hid = ACPI_THERMAL_HID;
 838                 break;
 839         case ACPI_BUS_TYPE_POWER_BUTTON:
 840                 hid = ACPI_BUTTON_HID_POWERF;
 841                 break;
 842         case ACPI_BUS_TYPE_SLEEP_BUTTON:
 843                 hid = ACPI_BUTTON_HID_SLEEPF;
 844                 break;
 845         }
 846
 847         /*
 848          * \_SB
 849          * ----
 850          * Fix for the system root bus device -- the only root-level device.
 851          */
 852         if (((acpi_handle)parent == ACPI_ROOT_OBJECT) && (type == ACPI_BUS_TYPE_DEVICE)) {
 853                 hid = ACPI_BUS_HID;
 854                 strcpy(device->pnp.device_name, ACPI_BUS_DEVICE_NAME);
 855                 strcpy(device->pnp.device_class, ACPI_BUS_CLASS);
 856         }
 857
 858         if (hid) {
 859                 strcpy(device->pnp.hardware_id, hid);
 860                 device->flags.hardware_id = 1;
 861         }
 862         if (uid) {
 863                 strcpy(device->pnp.unique_id, uid);
 864                 device->flags.unique_id = 1;
 865         }
 866         if (cid_list) {
 867                 device->pnp.cid_list = kmalloc(cid_list->size, GFP_KERNEL);
 868                 if (device->pnp.cid_list)
 869                         memcpy(device->pnp.cid_list, cid_list, cid_list->size);
 870                 else
 871                         printk(KERN_ERR "Memory allocation error\n");
 872         }
 873
 874         acpi_os_free(buffer.pointer);
 875 }
 876
 877 static int acpi_device_set_context(struct acpi_device *device, int type)
 878 {
 879         acpi_status status = AE_OK;
 880         int result = 0;
 881         /*
 882          * Context
 883          * -------
 884          * Attach this 'struct acpi_device' to the ACPI object.  This makes
 885          * resolutions from handle->device very efficient.  Note that we need
 886          * to be careful with fixed-feature devices as they all attach to the
 887          * root object.
 888          */
 889         if (type != ACPI_BUS_TYPE_POWER_BUTTON &&
 890             type != ACPI_BUS_TYPE_SLEEP_BUTTON) {
 891                 status = acpi_attach_data(device->handle,
 892                                           acpi_bus_data_handler, device);
 893
 894                 if (ACPI_FAILURE(status)) {
 895                         printk("Error attaching device data\n");
 896                         result = -ENODEV;
 897                 }
 898         }
 899         return result;
 900 }
 901
 902 static void acpi_device_get_debug_info(struct acpi_device *device,
 903                                        acpi_handle handle, int type)
 904 {
 905 #ifdef CONFIG_ACPI_DEBUG_OUTPUT
 906         char *type_string = NULL;
 907         char name[80] = { '?', '\0' };
 908         struct acpi_buffer buffer = { sizeof(name), name };
 909
 910         switch (type) {
 911         case ACPI_BUS_TYPE_DEVICE:
 912                 type_string = "Device";
 913                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 914                 break;
 915         case ACPI_BUS_TYPE_POWER:
 916                 type_string = "Power Resource";
 917                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 918                 break;
 919         case ACPI_BUS_TYPE_PROCESSOR:
 920                 type_string = "Processor";
 921                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 922                 break;
 923         case ACPI_BUS_TYPE_SYSTEM:
 924                 type_string = "System";
 925                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 926                 break;
 927         case ACPI_BUS_TYPE_THERMAL:
 928                 type_string = "Thermal Zone";
 929                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 930                 break;
 931         case ACPI_BUS_TYPE_POWER_BUTTON:
 932                 type_string = "Power Button";
 933                 sprintf(name, "PWRB");
 934                 break;
 935         case ACPI_BUS_TYPE_SLEEP_BUTTON:
 936                 type_string = "Sleep Button";
 937                 sprintf(name, "SLPB");
 938                 break;
 939         }
 940
 941         printk(KERN_DEBUG "Found %s %s [%p]\n", type_string, name, handle);
 942 #endif                          /*CONFIG_ACPI_DEBUG_OUTPUT */
 943 }
 944
 945 static int acpi_bus_remove(struct acpi_device *dev, int rmdevice)
 946 {
 947         int result = 0;
 948         struct acpi_driver *driver;
 949
 950         ACPI_FUNCTION_TRACE("acpi_bus_remove");
 951
 952         if (!dev)
 953                 return_VALUE(-EINVAL);
 954
 955         driver = dev->driver;
 956
 957         if ((driver) && (driver->ops.remove)) {
 958
 959                 if (driver->ops.stop) {
 960                         result = driver->ops.stop(dev, ACPI_BUS_REMOVAL_EJECT);
 961                         if (result)
 962                                 return_VALUE(result);
 963                 }
 964
 965                 result = dev->driver->ops.remove(dev, ACPI_BUS_REMOVAL_EJECT);
 966                 if (result) {
 967                         return_VALUE(result);
 968                 }
 969
 970                 atomic_dec(&dev->driver->references);
 971                 dev->driver = NULL;
 972                 acpi_driver_data(dev) = NULL;
 973         }
 974
 975         if (!rmdevice)
 976                 return_VALUE(0);
 977
 978         if (dev->flags.bus_address) {
 979                 if ((dev->parent) && (dev->parent->ops.unbind))
 980                         dev->parent->ops.unbind(dev);
 981         }
 982
 983         acpi_device_unregister(dev, ACPI_BUS_REMOVAL_EJECT);
 984
 985         return_VALUE(0);
 986 }
 987
 988 static int
 989 acpi_add_single_object(struct acpi_device **child,
 990                        struct acpi_device *parent, acpi_handle handle, int type)
 991 {
 992         int result = 0;
 993         struct acpi_device *device = NULL;
 994
 995         ACPI_FUNCTION_TRACE("acpi_add_single_object");
 996
 997         if (!child)
 998                 return_VALUE(-EINVAL);
 999
1000         device = kmalloc(sizeof(struct acpi_device), GFP_KERNEL);
1001         if (!device) {
1002                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Memory allocation error\n"));
1003                 return_VALUE(-ENOMEM);
1004         }
1005         memset(device, 0, sizeof(struct acpi_device));
1006
1007         device->handle = handle;
1008         device->parent = parent;
1009
1010         acpi_device_get_busid(device, handle, type);
1011
1012         /*
1013          * Flags
1014          * -----
1015          * Get prior to calling acpi_bus_get_status() so we know whether
1016          * or not _STA is present.  Note that we only look for object
1017          * handles -- cannot evaluate objects until we know the device is
1018          * present and properly initialized.
1019          */
1020         result = acpi_bus_get_flags(device);
1021         if (result)
1022                 goto end;
1023
1024         /*
1025          * Status
1026          * ------
1027          * See if the device is present.  We always assume that non-Device
1028          * and non-Processor objects (e.g. thermal zones, power resources,
1029          * etc.) are present, functioning, etc. (at least when parent object
1030          * is present).  Note that _STA has a different meaning for some
1031          * objects (e.g. power resources) so we need to be careful how we use
1032          * it.
1033          */
1034         switch (type) {
1035         case ACPI_BUS_TYPE_PROCESSOR:
1036         case ACPI_BUS_TYPE_DEVICE:
1037                 result = acpi_bus_get_status(device);
1038                 if (ACPI_FAILURE(result) || !device->status.present) {
1039                         result = -ENOENT;
1040                         goto end;
1041                 }
1042                 break;
1043         default:
1044                 STRUCT_TO_INT(device->status) = 0x0F;
1045                 break;
1046         }
1047
1048         /*
1049          * Initialize Device
1050          * -----------------
1051          * TBD: Synch with Core's enumeration/initialization process.
1052          */
1053
1054         /*
1055          * Hardware ID, Unique ID, & Bus Address
1056          * -------------------------------------
1057          */
1058         acpi_device_set_id(device, parent, handle, type);
1059
1060         /*
1061          * Power Management
1062          * ----------------
1063          */
1064         if (device->flags.power_manageable) {
1065                 result = acpi_bus_get_power_flags(device);
1066                 if (result)
1067                         goto end;
1068         }
1069
1070         /*
1071          * Wakeup device management
1072          *-----------------------
1073          */
1074         if (device->flags.wake_capable) {
1075                 result = acpi_bus_get_wakeup_device_flags(device);
1076                 if (result)
1077                         goto end;
1078         }
1079
1080         /*
1081          * Performance Management
1082          * ----------------------
1083          */
1084         if (device->flags.performance_manageable) {
1085                 result = acpi_bus_get_perf_flags(device);
1086                 if (result)
1087                         goto end;
1088         }
1089
1090         if ((result = acpi_device_set_context(device, type)))
1091                 goto end;
1092
1093         acpi_device_get_debug_info(device, handle, type);
1094
1095         acpi_device_register(device, parent);
1096
1097         /*
1098          * Bind _ADR-Based Devices
1099          * -----------------------
1100          * If there's a a bus address (_ADR) then we utilize the parent's
1101          * 'bind' function (if exists) to bind the ACPI- and natively-
1102          * enumerated device representations.
1103          */
1104         if (device->flags.bus_address) {
1105                 if (device->parent && device->parent->ops.bind)
1106                         device->parent->ops.bind(device);
1107         }
1108
1109         /*
1110          * Locate & Attach Driver
1111          * ----------------------
1112          * If there's a hardware id (_HID) or compatible ids (_CID) we check
1113          * to see if there's a driver installed for this kind of device.  Note
1114          * that drivers can install before or after a device is enumerated.
1115          *
1116          * TBD: Assumes LDM provides driver hot-plug capability.
1117          */
1118         acpi_bus_find_driver(device);
1119
1120       end:
1121         if (!result)
1122                 *child = device;
1123         else {
1124                 kfree(device->pnp.cid_list);
1125                 kfree(device);
1126         }
1127
1128         return_VALUE(result);
1129 }
1130
1131 static int acpi_bus_scan(struct acpi_device *start, struct acpi_bus_ops *ops)
1132 {
1133         acpi_status status = AE_OK;
1134         struct acpi_device *parent = NULL;
1135         struct acpi_device *child = NULL;
1136         acpi_handle phandle = NULL;
1137         acpi_handle chandle = NULL;
1138         acpi_object_type type = 0;
1139         u32 level = 1;
1140
1141         ACPI_FUNCTION_TRACE("acpi_bus_scan");
1142
1143         if (!start)
1144                 return_VALUE(-EINVAL);
1145
1146         parent = start;
1147         phandle = start->handle;
1148
1149         /*
1150          * Parse through the ACPI namespace, identify all 'devices', and
1151          * create a new 'struct acpi_device' for each.
1152          */
1153         while ((level > 0) && parent) {
1154
1155                 status = acpi_get_next_object(ACPI_TYPE_ANY, phandle,
1156                                               chandle, &chandle);
1157
1158                 /*
1159                  * If this scope is exhausted then move our way back up.
1160                  */
1161                 if (ACPI_FAILURE(status)) {
1162                         level--;
1163                         chandle = phandle;
1164                         acpi_get_parent(phandle, &phandle);
1165                         if (parent->parent)
1166                                 parent = parent->parent;
1167                         continue;
1168                 }
1169
1170                 status = acpi_get_type(chandle, &type);
1171                 if (ACPI_FAILURE(status))
1172                         continue;
1173
1174                 /*
1175                  * If this is a scope object then parse it (depth-first).
1176                  */
1177                 if (type == ACPI_TYPE_LOCAL_SCOPE) {
1178                         level++;
1179                         phandle = chandle;
1180                         chandle = NULL;
1181                         continue;
1182                 }
1183
1184                 /*
1185                  * We're only interested in objects that we consider 'devices'.
1186                  */
1187                 switch (type) {
1188                 case ACPI_TYPE_DEVICE:
1189                         type = ACPI_BUS_TYPE_DEVICE;
1190                         break;
1191                 case ACPI_TYPE_PROCESSOR:
1192                         type = ACPI_BUS_TYPE_PROCESSOR;
1193                         break;
1194                 case ACPI_TYPE_THERMAL:
1195                         type = ACPI_BUS_TYPE_THERMAL;
1196                         break;
1197                 case ACPI_TYPE_POWER:
1198                         type = ACPI_BUS_TYPE_POWER;
1199                         break;
1200                 default:
1201                         continue;
1202                 }
1203
1204                 if (ops->acpi_op_add)
1205                         status = acpi_add_single_object(&child, parent,
1206                                                         chandle, type);
1207                 else
1208                         status = acpi_bus_get_device(chandle, &child);
1209
1210                 if (ACPI_FAILURE(status))
1211                         continue;
1212
1213                 if (ops->acpi_op_start) {
1214                         status = acpi_start_single_object(child);
1215                         if (ACPI_FAILURE(status))
1216                                 continue;
1217                 }
1218
1219                 /*
1220                  * If the device is present, enabled, and functioning then
1221                  * parse its scope (depth-first).  Note that we need to
1222                  * represent absent devices to facilitate PnP notifications
1223                  * -- but only the subtree head (not all of its children,
1224                  * which will be enumerated when the parent is inserted).
1225                  *
1226                  * TBD: Need notifications and other detection mechanisms
1227                  *      in place before we can fully implement this.
1228                  */
1229                 if (child->status.present) {
1230                         status = acpi_get_next_object(ACPI_TYPE_ANY, chandle,
1231                                                       NULL, NULL);
1232                         if (ACPI_SUCCESS(status)) {
1233                                 level++;
1234                                 phandle = chandle;
1235                                 chandle = NULL;
1236                                 parent = child;
1237                         }
1238                 }
1239         }
1240
1241         return_VALUE(0);
1242 }
1243
1244 int
1245 acpi_bus_add(struct acpi_device **child,
1246              struct acpi_device *parent, acpi_handle handle, int type)
1247 {
1248         int result;
1249         struct acpi_bus_ops ops;
1250
1251         ACPI_FUNCTION_TRACE("acpi_bus_add");
1252
1253         result = acpi_add_single_object(child, parent, handle, type);
1254         if (!result) {
1255                 memset(&ops, 0, sizeof(ops));
1256                 ops.acpi_op_add = 1;
1257                 result = acpi_bus_scan(*child, &ops);
1258         }
1259         return_VALUE(result);
1260 }
1261
1262 EXPORT_SYMBOL(acpi_bus_add);
1263
1264 int acpi_bus_start(struct acpi_device *device)
1265 {
1266         int result;
1267         struct acpi_bus_ops ops;
1268
1269         ACPI_FUNCTION_TRACE("acpi_bus_start");
1270
1271         if (!device)
1272                 return_VALUE(-EINVAL);
1273
1274         result = acpi_start_single_object(device);
1275         if (!result) {
1276                 memset(&ops, 0, sizeof(ops));
1277                 ops.acpi_op_start = 1;
1278                 result = acpi_bus_scan(device, &ops);
1279         }
1280         return_VALUE(result);
1281 }
1282
1283 EXPORT_SYMBOL(acpi_bus_start);
1284
1285 int acpi_bus_trim(struct acpi_device *start, int rmdevice)
1286 {
1287         acpi_status status;
1288         struct acpi_device *parent, *child;
1289         acpi_handle phandle, chandle;
1290         acpi_object_type type;
1291         u32 level = 1;
1292         int err = 0;
1293
1294         parent = start;
1295         phandle = start->handle;
1296         child = chandle = NULL;
1297
1298         while ((level > 0) && parent && (!err)) {
1299                 status = acpi_get_next_object(ACPI_TYPE_ANY, phandle,
1300                                               chandle, &chandle);
1301
1302                 /*
1303                  * If this scope is exhausted then move our way back up.
1304                  */
1305                 if (ACPI_FAILURE(status)) {
1306                         level--;
1307                         chandle = phandle;
1308                         acpi_get_parent(phandle, &phandle);
1309                         child = parent;
1310                         parent = parent->parent;
1311
1312                         if (level == 0)
1313                                 err = acpi_bus_remove(child, rmdevice);
1314                         else
1315                                 err = acpi_bus_remove(child, 1);
1316
1317                         continue;
1318                 }
1319
1320                 status = acpi_get_type(chandle, &type);
1321                 if (ACPI_FAILURE(status)) {
1322                         continue;
1323                 }
1324                 /*
1325                  * If there is a device corresponding to chandle then
1326                  * parse it (depth-first).
1327                  */
1328                 if (acpi_bus_get_device(chandle, &child) == 0) {
1329                         level++;
1330                         phandle = chandle;
1331                         chandle = NULL;
1332                         parent = child;
1333                 }
1334                 continue;
1335         }
1336         return err;
1337 }
1338 EXPORT_SYMBOL_GPL(acpi_bus_trim);
1339
1340
1341 static int acpi_bus_scan_fixed(struct acpi_device *root)
1342 {
1343         int result = 0;
1344         struct acpi_device *device = NULL;
1345
1346         ACPI_FUNCTION_TRACE("acpi_bus_scan_fixed");
1347
1348         if (!root)
1349                 return_VALUE(-ENODEV);
1350
1351         /*
1352          * Enumerate all fixed-feature devices.
1353          */
1354         if (acpi_fadt.pwr_button == 0) {
1355                 result = acpi_add_single_object(&device, acpi_root,
1356                                                 NULL,
1357                                                 ACPI_BUS_TYPE_POWER_BUTTON);
1358                 if (!result)
1359                         result = acpi_start_single_object(device);
1360         }
1361
1362         if (acpi_fadt.sleep_button == 0) {
1363                 result = acpi_add_single_object(&device, acpi_root,
1364                                                 NULL,
1365                                                 ACPI_BUS_TYPE_SLEEP_BUTTON);
1366                 if (!result)
1367                         result = acpi_start_single_object(device);
1368         }
1369
1370         return_VALUE(result);
1371 }
1372
1373 static int __init acpi_scan_init(void)
1374 {
1375         int result;
1376         struct acpi_bus_ops ops;
1377
1378         ACPI_FUNCTION_TRACE("acpi_scan_init");
1379
1380         if (acpi_disabled)
1381                 return_VALUE(0);
1382
1383         kset_register(&acpi_namespace_kset);
1384
1385         /*
1386          * Create the root device in the bus's device tree
1387          */
1388         result = acpi_add_single_object(&acpi_root, NULL, ACPI_ROOT_OBJECT,
1389                                         ACPI_BUS_TYPE_SYSTEM);
1390         if (result)
1391                 goto Done;
1392
1393         result = acpi_start_single_object(acpi_root);
1394
1395         /*
1396          * Enumerate devices in the ACPI namespace.
1397          */
1398         result = acpi_bus_scan_fixed(acpi_root);
1399         if (!result) {
1400                 memset(&ops, 0, sizeof(ops));
1401                 ops.acpi_op_add = 1;
1402                 ops.acpi_op_start = 1;
1403                 result = acpi_bus_scan(acpi_root, &ops);
1404         }
1405
1406         if (result)
1407                 acpi_device_unregister(acpi_root, ACPI_BUS_REMOVAL_NORMAL);
1408
1409       Done:
1410         return_VALUE(result);
1411 }
1412
1413 subsys_initcall(acpi_scan_init);