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 static int acpi_bus_trim(struct acpi_device *start, int rmdevice);
  27
  28 static void acpi_device_release(struct kobject *kobj)
  29 {
  30         struct acpi_device *dev = container_of(kobj, struct acpi_device, kobj);
  31         if (dev->pnp.cid_list)
  32                 kfree(dev->pnp.cid_list);
  33         kfree(dev);
  34 }
  35
  36 struct acpi_device_attribute {
  37         struct attribute attr;
  38          ssize_t(*show) (struct acpi_device *, char *);
  39          ssize_t(*store) (struct acpi_device *, const char *, size_t);
  40 };
  41
  42 typedef void acpi_device_sysfs_files(struct kobject *,
  43                                      const struct attribute *);
  44
  45 static void setup_sys_fs_device_files(struct acpi_device *dev,
  46                                       acpi_device_sysfs_files * func);
  47
  48 #define create_sysfs_device_files(dev)  \
  49         setup_sys_fs_device_files(dev, (acpi_device_sysfs_files *)&sysfs_create_file)
  50 #define remove_sysfs_device_files(dev)  \
  51         setup_sys_fs_device_files(dev, (acpi_device_sysfs_files *)&sysfs_remove_file)
  52
  53 #define to_acpi_device(n) container_of(n, struct acpi_device, kobj)
  54 #define to_handle_attr(n) container_of(n, struct acpi_device_attribute, attr);
  55
  56 static ssize_t acpi_device_attr_show(struct kobject *kobj,
  57                                      struct attribute *attr, char *buf)
  58 {
  59         struct acpi_device *device = to_acpi_device(kobj);
  60         struct acpi_device_attribute *attribute = to_handle_attr(attr);
  61         return attribute->show ? attribute->show(device, buf) : -EIO;
  62 }
  63 static ssize_t acpi_device_attr_store(struct kobject *kobj,
  64                                       struct attribute *attr, const char *buf,
  65                                       size_t len)
  66 {
  67         struct acpi_device *device = to_acpi_device(kobj);
  68         struct acpi_device_attribute *attribute = to_handle_attr(attr);
  69         return attribute->store ? attribute->store(device, buf, len) : -EIO;
  70 }
  71
  72 static struct sysfs_ops acpi_device_sysfs_ops = {
  73         .show = acpi_device_attr_show,
  74         .store = acpi_device_attr_store,
  75 };
  76
  77 static struct kobj_type ktype_acpi_ns = {
  78         .sysfs_ops = &acpi_device_sysfs_ops,
  79         .release = acpi_device_release,
  80 };
  81
  82 static int namespace_hotplug(struct kset *kset, struct kobject *kobj,
  83                              char **envp, int num_envp, char *buffer,
  84                              int buffer_size)
  85 {
  86         struct acpi_device *dev = to_acpi_device(kobj);
  87         int i = 0;
  88         int len = 0;
  89
  90         if (!dev->driver)
  91                 return 0;
  92
  93         if (add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &len,
  94                                 "PHYSDEVDRIVER=%s", dev->driver->name))
  95                 return -ENOMEM;
  96
  97         envp[i] = NULL;
  98
  99         return 0;
 100 }
 101
 102 static struct kset_hotplug_ops namespace_hotplug_ops = {
 103         .hotplug = &namespace_hotplug,
 104 };
 105
 106 static struct kset acpi_namespace_kset = {
 107         .kobj = {
 108                  .name = "namespace",
 109                  },
 110         .subsys = &acpi_subsys,
 111         .ktype = &ktype_acpi_ns,
 112         .hotplug_ops = &namespace_hotplug_ops,
 113 };
 114
 115 static void acpi_device_register(struct acpi_device *device,
 116                                  struct acpi_device *parent)
 117 {
 118         /*
 119          * Linkage
 120          * -------
 121          * Link this device to its parent and siblings.
 122          */
 123         INIT_LIST_HEAD(&device->children);
 124         INIT_LIST_HEAD(&device->node);
 125         INIT_LIST_HEAD(&device->g_list);
 126         INIT_LIST_HEAD(&device->wakeup_list);
 127
 128         spin_lock(&acpi_device_lock);
 129         if (device->parent) {
 130                 list_add_tail(&device->node, &device->parent->children);
 131                 list_add_tail(&device->g_list, &device->parent->g_list);
 132         } else
 133                 list_add_tail(&device->g_list, &acpi_device_list);
 134         if (device->wakeup.flags.valid)
 135                 list_add_tail(&device->wakeup_list, &acpi_wakeup_device_list);
 136         spin_unlock(&acpi_device_lock);
 137
 138         strlcpy(device->kobj.name, device->pnp.bus_id, KOBJ_NAME_LEN);
 139         if (parent)
 140                 device->kobj.parent = &parent->kobj;
 141         device->kobj.ktype = &ktype_acpi_ns;
 142         device->kobj.kset = &acpi_namespace_kset;
 143         kobject_register(&device->kobj);
 144         create_sysfs_device_files(device);
 145 }
 146
 147 static int acpi_device_unregister(struct acpi_device *device, int type)
 148 {
 149         spin_lock(&acpi_device_lock);
 150         if (device->parent) {
 151                 list_del(&device->node);
 152                 list_del(&device->g_list);
 153         } else
 154                 list_del(&device->g_list);
 155
 156         list_del(&device->wakeup_list);
 157
 158         spin_unlock(&acpi_device_lock);
 159
 160         acpi_detach_data(device->handle, acpi_bus_data_handler);
 161         remove_sysfs_device_files(device);
 162         kobject_unregister(&device->kobj);
 163         return 0;
 164 }
 165
 166 void acpi_bus_data_handler(acpi_handle handle, u32 function, void *context)
 167 {
 168         ACPI_FUNCTION_TRACE("acpi_bus_data_handler");
 169
 170         /* TBD */
 171
 172         return_VOID;
 173 }
 174
 175 static int acpi_bus_get_power_flags(struct acpi_device *device)
 176 {
 177         acpi_status status = 0;
 178         acpi_handle handle = NULL;
 179         u32 i = 0;
 180
 181         ACPI_FUNCTION_TRACE("acpi_bus_get_power_flags");
 182
 183         /*
 184          * Power Management Flags
 185          */
 186         status = acpi_get_handle(device->handle, "_PSC", &handle);
 187         if (ACPI_SUCCESS(status))
 188                 device->power.flags.explicit_get = 1;
 189         status = acpi_get_handle(device->handle, "_IRC", &handle);
 190         if (ACPI_SUCCESS(status))
 191                 device->power.flags.inrush_current = 1;
 192
 193         /*
 194          * Enumerate supported power management states
 195          */
 196         for (i = ACPI_STATE_D0; i <= ACPI_STATE_D3; i++) {
 197                 struct acpi_device_power_state *ps = &device->power.states[i];
 198                 char object_name[5] = { '_', 'P', 'R', '0' + i, '\0' };
 199
 200                 /* Evaluate "_PRx" to se if power resources are referenced */
 201                 acpi_evaluate_reference(device->handle, object_name, NULL,
 202                                         &ps->resources);
 203                 if (ps->resources.count) {
 204                         device->power.flags.power_resources = 1;
 205                         ps->flags.valid = 1;
 206                 }
 207
 208                 /* Evaluate "_PSx" to see if we can do explicit sets */
 209                 object_name[2] = 'S';
 210                 status = acpi_get_handle(device->handle, object_name, &handle);
 211                 if (ACPI_SUCCESS(status)) {
 212                         ps->flags.explicit_set = 1;
 213                         ps->flags.valid = 1;
 214                 }
 215
 216                 /* State is valid if we have some power control */
 217                 if (ps->resources.count || ps->flags.explicit_set)
 218                         ps->flags.valid = 1;
 219
 220                 ps->power = -1; /* Unknown - driver assigned */
 221                 ps->latency = -1;       /* Unknown - driver assigned */
 222         }
 223
 224         /* Set defaults for D0 and D3 states (always valid) */
 225         device->power.states[ACPI_STATE_D0].flags.valid = 1;
 226         device->power.states[ACPI_STATE_D0].power = 100;
 227         device->power.states[ACPI_STATE_D3].flags.valid = 1;
 228         device->power.states[ACPI_STATE_D3].power = 0;
 229
 230         /* TBD: System wake support and resource requirements. */
 231
 232         device->power.state = ACPI_STATE_UNKNOWN;
 233
 234         return_VALUE(0);
 235 }
 236
 237 int acpi_match_ids(struct acpi_device *device, char *ids)
 238 {
 239         int error = 0;
 240         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 241
 242         if (device->flags.hardware_id)
 243                 if (strstr(ids, device->pnp.hardware_id))
 244                         goto Done;
 245
 246         if (device->flags.compatible_ids) {
 247                 struct acpi_compatible_id_list *cid_list = device->pnp.cid_list;
 248                 int i;
 249
 250                 /* compare multiple _CID entries against driver ids */
 251                 for (i = 0; i < cid_list->count; i++) {
 252                         if (strstr(ids, cid_list->id[i].value))
 253                                 goto Done;
 254                 }
 255         }
 256         error = -ENOENT;
 257
 258       Done:
 259         if (buffer.pointer)
 260                 acpi_os_free(buffer.pointer);
 261         return error;
 262 }
 263
 264 static acpi_status
 265 acpi_bus_extract_wakeup_device_power_package(struct acpi_device *device,
 266                                              union acpi_object *package)
 267 {
 268         int i = 0;
 269         union acpi_object *element = NULL;
 270
 271         if (!device || !package || (package->package.count < 2))
 272                 return AE_BAD_PARAMETER;
 273
 274         element = &(package->package.elements[0]);
 275         if (!element)
 276                 return AE_BAD_PARAMETER;
 277         if (element->type == ACPI_TYPE_PACKAGE) {
 278                 if ((element->package.count < 2) ||
 279                     (element->package.elements[0].type !=
 280                      ACPI_TYPE_LOCAL_REFERENCE)
 281                     || (element->package.elements[1].type != ACPI_TYPE_INTEGER))
 282                         return AE_BAD_DATA;
 283                 device->wakeup.gpe_device =
 284                     element->package.elements[0].reference.handle;
 285                 device->wakeup.gpe_number =
 286                     (u32) element->package.elements[1].integer.value;
 287         } else if (element->type == ACPI_TYPE_INTEGER) {
 288                 device->wakeup.gpe_number = element->integer.value;
 289         } else
 290                 return AE_BAD_DATA;
 291
 292         element = &(package->package.elements[1]);
 293         if (element->type != ACPI_TYPE_INTEGER) {
 294                 return AE_BAD_DATA;
 295         }
 296         device->wakeup.sleep_state = element->integer.value;
 297
 298         if ((package->package.count - 2) > ACPI_MAX_HANDLES) {
 299                 return AE_NO_MEMORY;
 300         }
 301         device->wakeup.resources.count = package->package.count - 2;
 302         for (i = 0; i < device->wakeup.resources.count; i++) {
 303                 element = &(package->package.elements[i + 2]);
 304                 if (element->type != ACPI_TYPE_ANY) {
 305                         return AE_BAD_DATA;
 306                 }
 307
 308                 device->wakeup.resources.handles[i] = element->reference.handle;
 309         }
 310
 311         return AE_OK;
 312 }
 313
 314 static int acpi_bus_get_wakeup_device_flags(struct acpi_device *device)
 315 {
 316         acpi_status status = 0;
 317         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 318         union acpi_object *package = NULL;
 319
 320         ACPI_FUNCTION_TRACE("acpi_bus_get_wakeup_flags");
 321
 322         /* _PRW */
 323         status = acpi_evaluate_object(device->handle, "_PRW", NULL, &buffer);
 324         if (ACPI_FAILURE(status)) {
 325                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _PRW\n"));
 326                 goto end;
 327         }
 328
 329         package = (union acpi_object *)buffer.pointer;
 330         status = acpi_bus_extract_wakeup_device_power_package(device, package);
 331         if (ACPI_FAILURE(status)) {
 332                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 333                                   "Error extracting _PRW package\n"));
 334                 goto end;
 335         }
 336
 337         acpi_os_free(buffer.pointer);
 338
 339         device->wakeup.flags.valid = 1;
 340         /* Power button, Lid switch always enable wakeup */
 341         if (!acpi_match_ids(device, "PNP0C0D,PNP0C0C,PNP0C0E"))
 342                 device->wakeup.flags.run_wake = 1;
 343
 344       end:
 345         if (ACPI_FAILURE(status))
 346                 device->flags.wake_capable = 0;
 347         return_VALUE(0);
 348 }
 349
 350 /* --------------------------------------------------------------------------
 351                 ACPI hotplug sysfs device file support
 352    -------------------------------------------------------------------------- */
 353 static ssize_t acpi_eject_store(struct acpi_device *device,
 354                                 const char *buf, size_t count);
 355
 356 #define ACPI_DEVICE_ATTR(_name,_mode,_show,_store) \
 357 static struct acpi_device_attribute acpi_device_attr_##_name = \
 358                 __ATTR(_name, _mode, _show, _store)
 359
 360 ACPI_DEVICE_ATTR(eject, 0200, NULL, acpi_eject_store);
 361
 362 /**
 363  * setup_sys_fs_device_files - sets up the device files under device namespace
 364  * @dev:        acpi_device object
 365  * @func:       function pointer to create or destroy the device file
 366  */
 367 static void
 368 setup_sys_fs_device_files(struct acpi_device *dev,
 369                           acpi_device_sysfs_files * func)
 370 {
 371         acpi_status status;
 372         acpi_handle temp = NULL;
 373
 374         /*
 375          * If device has _EJ0, 'eject' file is created that is used to trigger
 376          * hot-removal function from userland.
 377          */
 378         status = acpi_get_handle(dev->handle, "_EJ0", &temp);
 379         if (ACPI_SUCCESS(status))
 380                 (*(func)) (&dev->kobj, &acpi_device_attr_eject.attr);
 381 }
 382
 383 static int acpi_eject_operation(acpi_handle handle, int lockable)
 384 {
 385         struct acpi_object_list arg_list;
 386         union acpi_object arg;
 387         acpi_status status = AE_OK;
 388
 389         /*
 390          * TBD: evaluate _PS3?
 391          */
 392
 393         if (lockable) {
 394                 arg_list.count = 1;
 395                 arg_list.pointer = &arg;
 396                 arg.type = ACPI_TYPE_INTEGER;
 397                 arg.integer.value = 0;
 398                 acpi_evaluate_object(handle, "_LCK", &arg_list, NULL);
 399         }
 400
 401         arg_list.count = 1;
 402         arg_list.pointer = &arg;
 403         arg.type = ACPI_TYPE_INTEGER;
 404         arg.integer.value = 1;
 405
 406         /*
 407          * TBD: _EJD support.
 408          */
 409
 410         status = acpi_evaluate_object(handle, "_EJ0", &arg_list, NULL);
 411         if (ACPI_FAILURE(status)) {
 412                 return (-ENODEV);
 413         }
 414
 415         return (0);
 416 }
 417
 418 static ssize_t
 419 acpi_eject_store(struct acpi_device *device, const char *buf, size_t count)
 420 {
 421         int result;
 422         int ret = count;
 423         int islockable;
 424         acpi_status status;
 425         acpi_handle handle;
 426         acpi_object_type type = 0;
 427
 428         if ((!count) || (buf[0] != '1')) {
 429                 return -EINVAL;
 430         }
 431 #ifndef FORCE_EJECT
 432         if (device->driver == NULL) {
 433                 ret = -ENODEV;
 434                 goto err;
 435         }
 436 #endif
 437         status = acpi_get_type(device->handle, &type);
 438         if (ACPI_FAILURE(status) || (!device->flags.ejectable)) {
 439                 ret = -ENODEV;
 440                 goto err;
 441         }
 442
 443         islockable = device->flags.lockable;
 444         handle = device->handle;
 445
 446         if (type == ACPI_TYPE_PROCESSOR)
 447                 result = acpi_bus_trim(device, 0);
 448         else
 449                 result = acpi_bus_trim(device, 1);
 450
 451         if (!result)
 452                 result = acpi_eject_operation(handle, islockable);
 453
 454         if (result) {
 455                 ret = -EBUSY;
 456         }
 457       err:
 458         return ret;
 459 }
 460
 461 /* --------------------------------------------------------------------------
 462                               Performance Management
 463    -------------------------------------------------------------------------- */
 464
 465 static int acpi_bus_get_perf_flags(struct acpi_device *device)
 466 {
 467         device->performance.state = ACPI_STATE_UNKNOWN;
 468         return 0;
 469 }
 470
 471 /* --------------------------------------------------------------------------
 472                                  Driver Management
 473    -------------------------------------------------------------------------- */
 474
 475 static LIST_HEAD(acpi_bus_drivers);
 476 static DECLARE_MUTEX(acpi_bus_drivers_lock);
 477
 478 /**
 479  * acpi_bus_match
 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
 494  * --------------------
 495  * Used to initialize a device via its device driver.  Called whenever a
 496  * driver is bound to a device.  Invokes the driver's add() and start() ops.
 497  */
 498 static int
 499 acpi_bus_driver_init(struct acpi_device *device, struct acpi_driver *driver)
 500 {
 501         int result = 0;
 502
 503         ACPI_FUNCTION_TRACE("acpi_bus_driver_init");
 504
 505         if (!device || !driver)
 506                 return_VALUE(-EINVAL);
 507
 508         if (!driver->ops.add)
 509                 return_VALUE(-ENOSYS);
 510
 511         result = driver->ops.add(device);
 512         if (result) {
 513                 device->driver = NULL;
 514                 acpi_driver_data(device) = NULL;
 515                 return_VALUE(result);
 516         }
 517
 518         device->driver = driver;
 519
 520         /*
 521          * TBD - Configuration Management: Assign resources to device based
 522          * upon possible configuration and currently allocated resources.
 523          */
 524
 525         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 526                           "Driver successfully bound to device\n"));
 527         return_VALUE(0);
 528 }
 529
 530 static int acpi_start_single_object(struct acpi_device *device)
 531 {
 532         int result = 0;
 533         struct acpi_driver *driver;
 534
 535         ACPI_FUNCTION_TRACE("acpi_start_single_object");
 536
 537         if (!(driver = device->driver))
 538                 return_VALUE(0);
 539
 540         if (driver->ops.start) {
 541                 result = driver->ops.start(device);
 542                 if (result && driver->ops.remove)
 543                         driver->ops.remove(device, ACPI_BUS_REMOVAL_NORMAL);
 544         }
 545
 546         return_VALUE(result);
 547 }
 548
 549 static int acpi_driver_attach(struct acpi_driver *drv)
 550 {
 551         struct list_head *node, *next;
 552         int count = 0;
 553
 554         ACPI_FUNCTION_TRACE("acpi_driver_attach");
 555
 556         spin_lock(&acpi_device_lock);
 557         list_for_each_safe(node, next, &acpi_device_list) {
 558                 struct acpi_device *dev =
 559                     container_of(node, struct acpi_device, g_list);
 560
 561                 if (dev->driver || !dev->status.present)
 562                         continue;
 563                 spin_unlock(&acpi_device_lock);
 564
 565                 if (!acpi_bus_match(dev, drv)) {
 566                         if (!acpi_bus_driver_init(dev, drv)) {
 567                                 acpi_start_single_object(dev);
 568                                 atomic_inc(&drv->references);
 569                                 count++;
 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         return_VALUE(count);
 579 }
 580
 581 static int acpi_driver_detach(struct acpi_driver *drv)
 582 {
 583         struct list_head *node, *next;
 584
 585         ACPI_FUNCTION_TRACE("acpi_driver_detach");
 586
 587         spin_lock(&acpi_device_lock);
 588         list_for_each_safe(node, next, &acpi_device_list) {
 589                 struct acpi_device *dev =
 590                     container_of(node, struct acpi_device, g_list);
 591
 592                 if (dev->driver == drv) {
 593                         spin_unlock(&acpi_device_lock);
 594                         if (drv->ops.remove)
 595                                 drv->ops.remove(dev, ACPI_BUS_REMOVAL_NORMAL);
 596                         spin_lock(&acpi_device_lock);
 597                         dev->driver = NULL;
 598                         dev->driver_data = NULL;
 599                         atomic_dec(&drv->references);
 600                 }
 601         }
 602         spin_unlock(&acpi_device_lock);
 603         return_VALUE(0);
 604 }
 605
 606 /**
 607  * acpi_bus_register_driver
 608  * ------------------------
 609  * Registers a driver with the ACPI bus.  Searches the namespace for all
 610  * devices that match the driver's criteria and binds.  Returns the
 611  * number of devices that were claimed by the driver, or a negative
 612  * error status for failure.
 613  */
 614 int acpi_bus_register_driver(struct acpi_driver *driver)
 615 {
 616         int count;
 617
 618         ACPI_FUNCTION_TRACE("acpi_bus_register_driver");
 619
 620         if (acpi_disabled)
 621                 return_VALUE(-ENODEV);
 622
 623         if (!driver)
 624                 return_VALUE(-EINVAL);
 625
 626         spin_lock(&acpi_device_lock);
 627         list_add_tail(&driver->node, &acpi_bus_drivers);
 628         spin_unlock(&acpi_device_lock);
 629         count = acpi_driver_attach(driver);
 630
 631         return_VALUE(count);
 632 }
 633
 634 EXPORT_SYMBOL(acpi_bus_register_driver);
 635
 636 /**
 637  * acpi_bus_unregister_driver
 638  * --------------------------
 639  * Unregisters a driver with the ACPI bus.  Searches the namespace for all
 640  * devices that match the driver's criteria and unbinds.
 641  */
 642 int acpi_bus_unregister_driver(struct acpi_driver *driver)
 643 {
 644         int error = 0;
 645
 646         ACPI_FUNCTION_TRACE("acpi_bus_unregister_driver");
 647
 648         if (driver) {
 649                 acpi_driver_detach(driver);
 650
 651                 if (!atomic_read(&driver->references)) {
 652                         spin_lock(&acpi_device_lock);
 653                         list_del_init(&driver->node);
 654                         spin_unlock(&acpi_device_lock);
 655                 }
 656         } else
 657                 error = -EINVAL;
 658         return_VALUE(error);
 659 }
 660
 661 EXPORT_SYMBOL(acpi_bus_unregister_driver);
 662
 663 /**
 664  * acpi_bus_find_driver
 665  * --------------------
 666  * Parses the list of registered drivers looking for a driver applicable for
 667  * the specified device.
 668  */
 669 static int acpi_bus_find_driver(struct acpi_device *device)
 670 {
 671         int result = 0;
 672         struct list_head *node, *next;
 673
 674         ACPI_FUNCTION_TRACE("acpi_bus_find_driver");
 675
 676         spin_lock(&acpi_device_lock);
 677         list_for_each_safe(node, next, &acpi_bus_drivers) {
 678                 struct acpi_driver *driver =
 679                     container_of(node, struct acpi_driver, node);
 680
 681                 atomic_inc(&driver->references);
 682                 spin_unlock(&acpi_device_lock);
 683                 if (!acpi_bus_match(device, driver)) {
 684                         result = acpi_bus_driver_init(device, driver);
 685                         if (!result)
 686                                 goto Done;
 687                 }
 688                 atomic_dec(&driver->references);
 689                 spin_lock(&acpi_device_lock);
 690         }
 691         spin_unlock(&acpi_device_lock);
 692
 693       Done:
 694         return_VALUE(result);
 695 }
 696
 697 /* --------------------------------------------------------------------------
 698                                  Device Enumeration
 699    -------------------------------------------------------------------------- */
 700
 701 static int acpi_bus_get_flags(struct acpi_device *device)
 702 {
 703         acpi_status status = AE_OK;
 704         acpi_handle temp = NULL;
 705
 706         ACPI_FUNCTION_TRACE("acpi_bus_get_flags");
 707
 708         /* Presence of _STA indicates 'dynamic_status' */
 709         status = acpi_get_handle(device->handle, "_STA", &temp);
 710         if (ACPI_SUCCESS(status))
 711                 device->flags.dynamic_status = 1;
 712
 713         /* Presence of _CID indicates 'compatible_ids' */
 714         status = acpi_get_handle(device->handle, "_CID", &temp);
 715         if (ACPI_SUCCESS(status))
 716                 device->flags.compatible_ids = 1;
 717
 718         /* Presence of _RMV indicates 'removable' */
 719         status = acpi_get_handle(device->handle, "_RMV", &temp);
 720         if (ACPI_SUCCESS(status))
 721                 device->flags.removable = 1;
 722
 723         /* Presence of _EJD|_EJ0 indicates 'ejectable' */
 724         status = acpi_get_handle(device->handle, "_EJD", &temp);
 725         if (ACPI_SUCCESS(status))
 726                 device->flags.ejectable = 1;
 727         else {
 728                 status = acpi_get_handle(device->handle, "_EJ0", &temp);
 729                 if (ACPI_SUCCESS(status))
 730                         device->flags.ejectable = 1;
 731         }
 732
 733         /* Presence of _LCK indicates 'lockable' */
 734         status = acpi_get_handle(device->handle, "_LCK", &temp);
 735         if (ACPI_SUCCESS(status))
 736                 device->flags.lockable = 1;
 737
 738         /* Presence of _PS0|_PR0 indicates 'power manageable' */
 739         status = acpi_get_handle(device->handle, "_PS0", &temp);
 740         if (ACPI_FAILURE(status))
 741                 status = acpi_get_handle(device->handle, "_PR0", &temp);
 742         if (ACPI_SUCCESS(status))
 743                 device->flags.power_manageable = 1;
 744
 745         /* Presence of _PRW indicates wake capable */
 746         status = acpi_get_handle(device->handle, "_PRW", &temp);
 747         if (ACPI_SUCCESS(status))
 748                 device->flags.wake_capable = 1;
 749
 750         /* TBD: Peformance management */
 751
 752         return_VALUE(0);
 753 }
 754
 755 static void acpi_device_get_busid(struct acpi_device *device,
 756                                   acpi_handle handle, int type)
 757 {
 758         char bus_id[5] = { '?', 0 };
 759         struct acpi_buffer buffer = { sizeof(bus_id), bus_id };
 760         int i = 0;
 761
 762         /*
 763          * Bus ID
 764          * ------
 765          * The device's Bus ID is simply the object name.
 766          * TBD: Shouldn't this value be unique (within the ACPI namespace)?
 767          */
 768         switch (type) {
 769         case ACPI_BUS_TYPE_SYSTEM:
 770                 strcpy(device->pnp.bus_id, "ACPI");
 771                 break;
 772         case ACPI_BUS_TYPE_POWER_BUTTON:
 773                 strcpy(device->pnp.bus_id, "PWRF");
 774                 break;
 775         case ACPI_BUS_TYPE_SLEEP_BUTTON:
 776                 strcpy(device->pnp.bus_id, "SLPF");
 777                 break;
 778         default:
 779                 acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
 780                 /* Clean up trailing underscores (if any) */
 781                 for (i = 3; i > 1; i--) {
 782                         if (bus_id[i] == '_')
 783                                 bus_id[i] = '\0';
 784                         else
 785                                 break;
 786                 }
 787                 strcpy(device->pnp.bus_id, bus_id);
 788                 break;
 789         }
 790 }
 791
 792 static void acpi_device_set_id(struct acpi_device *device,
 793                                struct acpi_device *parent, acpi_handle handle,
 794                                int type)
 795 {
 796         struct acpi_device_info *info;
 797         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 798         char *hid = NULL;
 799         char *uid = NULL;
 800         struct acpi_compatible_id_list *cid_list = NULL;
 801         acpi_status status;
 802
 803         switch (type) {
 804         case ACPI_BUS_TYPE_DEVICE:
 805                 status = acpi_get_object_info(handle, &buffer);
 806                 if (ACPI_FAILURE(status)) {
 807                         printk("%s: Error reading device info\n", __FUNCTION__);
 808                         return;
 809                 }
 810
 811                 info = buffer.pointer;
 812                 if (info->valid & ACPI_VALID_HID)
 813                         hid = info->hardware_id.value;
 814                 if (info->valid & ACPI_VALID_UID)
 815                         uid = info->unique_id.value;
 816                 if (info->valid & ACPI_VALID_CID)
 817                         cid_list = &info->compatibility_id;
 818                 if (info->valid & ACPI_VALID_ADR) {
 819                         device->pnp.bus_address = info->address;
 820                         device->flags.bus_address = 1;
 821                 }
 822                 break;
 823         case ACPI_BUS_TYPE_POWER:
 824                 hid = ACPI_POWER_HID;
 825                 break;
 826         case ACPI_BUS_TYPE_PROCESSOR:
 827                 hid = ACPI_PROCESSOR_HID;
 828                 break;
 829         case ACPI_BUS_TYPE_SYSTEM:
 830                 hid = ACPI_SYSTEM_HID;
 831                 break;
 832         case ACPI_BUS_TYPE_THERMAL:
 833                 hid = ACPI_THERMAL_HID;
 834                 break;
 835         case ACPI_BUS_TYPE_POWER_BUTTON:
 836                 hid = ACPI_BUTTON_HID_POWERF;
 837                 break;
 838         case ACPI_BUS_TYPE_SLEEP_BUTTON:
 839                 hid = ACPI_BUTTON_HID_SLEEPF;
 840                 break;
 841         }
 842
 843         /*
 844          * \_SB
 845          * ----
 846          * Fix for the system root bus device -- the only root-level device.
 847          */
 848         if ((parent == ACPI_ROOT_OBJECT) && (type == ACPI_BUS_TYPE_DEVICE)) {
 849                 hid = ACPI_BUS_HID;
 850                 strcpy(device->pnp.device_name, ACPI_BUS_DEVICE_NAME);
 851                 strcpy(device->pnp.device_class, ACPI_BUS_CLASS);
 852         }
 853
 854         if (hid) {
 855                 strcpy(device->pnp.hardware_id, hid);
 856                 device->flags.hardware_id = 1;
 857         }
 858         if (uid) {
 859                 strcpy(device->pnp.unique_id, uid);
 860                 device->flags.unique_id = 1;
 861         }
 862         if (cid_list) {
 863                 device->pnp.cid_list = kmalloc(cid_list->size, GFP_KERNEL);
 864                 if (device->pnp.cid_list)
 865                         memcpy(device->pnp.cid_list, cid_list, cid_list->size);
 866                 else
 867                         printk(KERN_ERR "Memory allocation error\n");
 868         }
 869
 870         acpi_os_free(buffer.pointer);
 871 }
 872
 873 static int acpi_device_set_context(struct acpi_device *device, int type)
 874 {
 875         acpi_status status = AE_OK;
 876         int result = 0;
 877         /*
 878          * Context
 879          * -------
 880          * Attach this 'struct acpi_device' to the ACPI object.  This makes
 881          * resolutions from handle->device very efficient.  Note that we need
 882          * to be careful with fixed-feature devices as they all attach to the
 883          * root object.
 884          */
 885         if (type != ACPI_BUS_TYPE_POWER_BUTTON &&
 886             type != ACPI_BUS_TYPE_SLEEP_BUTTON) {
 887                 status = acpi_attach_data(device->handle,
 888                                           acpi_bus_data_handler, device);
 889
 890                 if (ACPI_FAILURE(status)) {
 891                         printk("Error attaching device data\n");
 892                         result = -ENODEV;
 893                 }
 894         }
 895         return result;
 896 }
 897
 898 static void acpi_device_get_debug_info(struct acpi_device *device,
 899                                        acpi_handle handle, int type)
 900 {
 901 #ifdef CONFIG_ACPI_DEBUG_OUTPUT
 902         char *type_string = NULL;
 903         char name[80] = { '?', '\0' };
 904         struct acpi_buffer buffer = { sizeof(name), name };
 905
 906         switch (type) {
 907         case ACPI_BUS_TYPE_DEVICE:
 908                 type_string = "Device";
 909                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 910                 break;
 911         case ACPI_BUS_TYPE_POWER:
 912                 type_string = "Power Resource";
 913                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 914                 break;
 915         case ACPI_BUS_TYPE_PROCESSOR:
 916                 type_string = "Processor";
 917                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 918                 break;
 919         case ACPI_BUS_TYPE_SYSTEM:
 920                 type_string = "System";
 921                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 922                 break;
 923         case ACPI_BUS_TYPE_THERMAL:
 924                 type_string = "Thermal Zone";
 925                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 926                 break;
 927         case ACPI_BUS_TYPE_POWER_BUTTON:
 928                 type_string = "Power Button";
 929                 sprintf(name, "PWRB");
 930                 break;
 931         case ACPI_BUS_TYPE_SLEEP_BUTTON:
 932                 type_string = "Sleep Button";
 933                 sprintf(name, "SLPB");
 934                 break;
 935         }
 936
 937         printk(KERN_DEBUG "Found %s %s [%p]\n", type_string, name, handle);
 938 #endif                          /*CONFIG_ACPI_DEBUG_OUTPUT */
 939 }
 940
 941 static int acpi_bus_remove(struct acpi_device *dev, int rmdevice)
 942 {
 943         int result = 0;
 944         struct acpi_driver *driver;
 945
 946         ACPI_FUNCTION_TRACE("acpi_bus_remove");
 947
 948         if (!dev)
 949                 return_VALUE(-EINVAL);
 950
 951         driver = dev->driver;
 952
 953         if ((driver) && (driver->ops.remove)) {
 954
 955                 if (driver->ops.stop) {
 956                         result = driver->ops.stop(dev, ACPI_BUS_REMOVAL_EJECT);
 957                         if (result)
 958                                 return_VALUE(result);
 959                 }
 960
 961                 result = dev->driver->ops.remove(dev, ACPI_BUS_REMOVAL_EJECT);
 962                 if (result) {
 963                         return_VALUE(result);
 964                 }
 965
 966                 atomic_dec(&dev->driver->references);
 967                 dev->driver = NULL;
 968                 acpi_driver_data(dev) = NULL;
 969         }
 970
 971         if (!rmdevice)
 972                 return_VALUE(0);
 973
 974         if (dev->flags.bus_address) {
 975                 if ((dev->parent) && (dev->parent->ops.unbind))
 976                         dev->parent->ops.unbind(dev);
 977         }
 978
 979         acpi_device_unregister(dev, ACPI_BUS_REMOVAL_EJECT);
 980
 981         return_VALUE(0);
 982 }
 983
 984 static int
 985 acpi_add_single_object(struct acpi_device **child,
 986                        struct acpi_device *parent, acpi_handle handle, int type)
 987 {
 988         int result = 0;
 989         struct acpi_device *device = NULL;
 990
 991         ACPI_FUNCTION_TRACE("acpi_add_single_object");
 992
 993         if (!child)
 994                 return_VALUE(-EINVAL);
 995
 996         device = kmalloc(sizeof(struct acpi_device), GFP_KERNEL);
 997         if (!device) {
 998                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Memory allocation error\n"));
 999                 return_VALUE(-ENOMEM);
1000         }
1001         memset(device, 0, sizeof(struct acpi_device));
1002
1003         device->handle = handle;
1004         device->parent = parent;
1005
1006         acpi_device_get_busid(device, handle, type);
1007
1008         /*
1009          * Flags
1010          * -----
1011          * Get prior to calling acpi_bus_get_status() so we know whether
1012          * or not _STA is present.  Note that we only look for object
1013          * handles -- cannot evaluate objects until we know the device is
1014          * present and properly initialized.
1015          */
1016         result = acpi_bus_get_flags(device);
1017         if (result)
1018                 goto end;
1019
1020         /*
1021          * Status
1022          * ------
1023          * See if the device is present.  We always assume that non-Device
1024          * and non-Processor objects (e.g. thermal zones, power resources,
1025          * etc.) are present, functioning, etc. (at least when parent object
1026          * is present).  Note that _STA has a different meaning for some
1027          * objects (e.g. power resources) so we need to be careful how we use
1028          * it.
1029          */
1030         switch (type) {
1031         case ACPI_BUS_TYPE_PROCESSOR:
1032         case ACPI_BUS_TYPE_DEVICE:
1033                 result = acpi_bus_get_status(device);
1034                 if (ACPI_FAILURE(result) || !device->status.present) {
1035                         result = -ENOENT;
1036                         goto end;
1037                 }
1038                 break;
1039         default:
1040                 STRUCT_TO_INT(device->status) = 0x0F;
1041                 break;
1042         }
1043
1044         /*
1045          * Initialize Device
1046          * -----------------
1047          * TBD: Synch with Core's enumeration/initialization process.
1048          */
1049
1050         /*
1051          * Hardware ID, Unique ID, & Bus Address
1052          * -------------------------------------
1053          */
1054         acpi_device_set_id(device, parent, handle, type);
1055
1056         /*
1057          * Power Management
1058          * ----------------
1059          */
1060         if (device->flags.power_manageable) {
1061                 result = acpi_bus_get_power_flags(device);
1062                 if (result)
1063                         goto end;
1064         }
1065
1066         /*
1067          * Wakeup device management
1068          *-----------------------
1069          */
1070         if (device->flags.wake_capable) {
1071                 result = acpi_bus_get_wakeup_device_flags(device);
1072                 if (result)
1073                         goto end;
1074         }
1075
1076         /*
1077          * Performance Management
1078          * ----------------------
1079          */
1080         if (device->flags.performance_manageable) {
1081                 result = acpi_bus_get_perf_flags(device);
1082                 if (result)
1083                         goto end;
1084         }
1085
1086         if ((result = acpi_device_set_context(device, type)))
1087                 goto end;
1088
1089         acpi_device_get_debug_info(device, handle, type);
1090
1091         acpi_device_register(device, parent);
1092
1093         /*
1094          * Bind _ADR-Based Devices
1095          * -----------------------
1096          * If there's a a bus address (_ADR) then we utilize the parent's
1097          * 'bind' function (if exists) to bind the ACPI- and natively-
1098          * enumerated device representations.
1099          */
1100         if (device->flags.bus_address) {
1101                 if (device->parent && device->parent->ops.bind)
1102                         device->parent->ops.bind(device);
1103         }
1104
1105         /*
1106          * Locate & Attach Driver
1107          * ----------------------
1108          * If there's a hardware id (_HID) or compatible ids (_CID) we check
1109          * to see if there's a driver installed for this kind of device.  Note
1110          * that drivers can install before or after a device is enumerated.
1111          *
1112          * TBD: Assumes LDM provides driver hot-plug capability.
1113          */
1114         result = acpi_bus_find_driver(device);
1115
1116       end:
1117         if (!result)
1118                 *child = device;
1119         else {
1120                 if (device->pnp.cid_list)
1121                         kfree(device->pnp.cid_list);
1122                 kfree(device);
1123         }
1124
1125         return_VALUE(result);
1126 }
1127
1128 static int acpi_bus_scan(struct acpi_device *start, struct acpi_bus_ops *ops)
1129 {
1130         acpi_status status = AE_OK;
1131         struct acpi_device *parent = NULL;
1132         struct acpi_device *child = NULL;
1133         acpi_handle phandle = NULL;
1134         acpi_handle chandle = NULL;
1135         acpi_object_type type = 0;
1136         u32 level = 1;
1137
1138         ACPI_FUNCTION_TRACE("acpi_bus_scan");
1139
1140         if (!start)
1141                 return_VALUE(-EINVAL);
1142
1143         parent = start;
1144         phandle = start->handle;
1145
1146         /*
1147          * Parse through the ACPI namespace, identify all 'devices', and
1148          * create a new 'struct acpi_device' for each.
1149          */
1150         while ((level > 0) && parent) {
1151
1152                 status = acpi_get_next_object(ACPI_TYPE_ANY, phandle,
1153                                               chandle, &chandle);
1154
1155                 /*
1156                  * If this scope is exhausted then move our way back up.
1157                  */
1158                 if (ACPI_FAILURE(status)) {
1159                         level--;
1160                         chandle = phandle;
1161                         acpi_get_parent(phandle, &phandle);
1162                         if (parent->parent)
1163                                 parent = parent->parent;
1164                         continue;
1165                 }
1166
1167                 status = acpi_get_type(chandle, &type);
1168                 if (ACPI_FAILURE(status))
1169                         continue;
1170
1171                 /*
1172                  * If this is a scope object then parse it (depth-first).
1173                  */
1174                 if (type == ACPI_TYPE_LOCAL_SCOPE) {
1175                         level++;
1176                         phandle = chandle;
1177                         chandle = NULL;
1178                         continue;
1179                 }
1180
1181                 /*
1182                  * We're only interested in objects that we consider 'devices'.
1183                  */
1184                 switch (type) {
1185                 case ACPI_TYPE_DEVICE:
1186                         type = ACPI_BUS_TYPE_DEVICE;
1187                         break;
1188                 case ACPI_TYPE_PROCESSOR:
1189                         type = ACPI_BUS_TYPE_PROCESSOR;
1190                         break;
1191                 case ACPI_TYPE_THERMAL:
1192                         type = ACPI_BUS_TYPE_THERMAL;
1193                         break;
1194                 case ACPI_TYPE_POWER:
1195                         type = ACPI_BUS_TYPE_POWER;
1196                         break;
1197                 default:
1198                         continue;
1199                 }
1200
1201                 if (ops->acpi_op_add)
1202                         status = acpi_add_single_object(&child, parent,
1203                                                         chandle, type);
1204                 else
1205                         status = acpi_bus_get_device(chandle, &child);
1206
1207                 if (ACPI_FAILURE(status))
1208                         continue;
1209
1210                 if (ops->acpi_op_start) {
1211                         status = acpi_start_single_object(child);
1212                         if (ACPI_FAILURE(status))
1213                                 continue;
1214                 }
1215
1216                 /*
1217                  * If the device is present, enabled, and functioning then
1218                  * parse its scope (depth-first).  Note that we need to
1219                  * represent absent devices to facilitate PnP notifications
1220                  * -- but only the subtree head (not all of its children,
1221                  * which will be enumerated when the parent is inserted).
1222                  *
1223                  * TBD: Need notifications and other detection mechanisms
1224                  *      in place before we can fully implement this.
1225                  */
1226                 if (child->status.present) {
1227                         status = acpi_get_next_object(ACPI_TYPE_ANY, chandle,
1228                                                       NULL, NULL);
1229                         if (ACPI_SUCCESS(status)) {
1230                                 level++;
1231                                 phandle = chandle;
1232                                 chandle = NULL;
1233                                 parent = child;
1234                         }
1235                 }
1236         }
1237
1238         return_VALUE(0);
1239 }
1240
1241 int
1242 acpi_bus_add(struct acpi_device **child,
1243              struct acpi_device *parent, acpi_handle handle, int type)
1244 {
1245         int result;
1246         struct acpi_bus_ops ops;
1247
1248         ACPI_FUNCTION_TRACE("acpi_bus_add");
1249
1250         result = acpi_add_single_object(child, parent, handle, type);
1251         if (!result) {
1252                 memset(&ops, 0, sizeof(ops));
1253                 ops.acpi_op_add = 1;
1254                 result = acpi_bus_scan(*child, &ops);
1255         }
1256         return_VALUE(result);
1257 }
1258
1259 EXPORT_SYMBOL(acpi_bus_add);
1260
1261 int acpi_bus_start(struct acpi_device *device)
1262 {
1263         int result;
1264         struct acpi_bus_ops ops;
1265
1266         ACPI_FUNCTION_TRACE("acpi_bus_start");
1267
1268         if (!device)
1269                 return_VALUE(-EINVAL);
1270
1271         result = acpi_start_single_object(device);
1272         if (!result) {
1273                 memset(&ops, 0, sizeof(ops));
1274                 ops.acpi_op_start = 1;
1275                 result = acpi_bus_scan(device, &ops);
1276         }
1277         return_VALUE(result);
1278 }
1279
1280 EXPORT_SYMBOL(acpi_bus_start);
1281
1282 static int acpi_bus_trim(struct acpi_device *start, int rmdevice)
1283 {
1284         acpi_status status;
1285         struct acpi_device *parent, *child;
1286         acpi_handle phandle, chandle;
1287         acpi_object_type type;
1288         u32 level = 1;
1289         int err = 0;
1290
1291         parent = start;
1292         phandle = start->handle;
1293         child = chandle = NULL;
1294
1295         while ((level > 0) && parent && (!err)) {
1296                 status = acpi_get_next_object(ACPI_TYPE_ANY, phandle,
1297                                               chandle, &chandle);
1298
1299                 /*
1300                  * If this scope is exhausted then move our way back up.
1301                  */
1302                 if (ACPI_FAILURE(status)) {
1303                         level--;
1304                         chandle = phandle;
1305                         acpi_get_parent(phandle, &phandle);
1306                         child = parent;
1307                         parent = parent->parent;
1308
1309                         if (level == 0)
1310                                 err = acpi_bus_remove(child, rmdevice);
1311                         else
1312                                 err = acpi_bus_remove(child, 1);
1313
1314                         continue;
1315                 }
1316
1317                 status = acpi_get_type(chandle, &type);
1318                 if (ACPI_FAILURE(status)) {
1319                         continue;
1320                 }
1321                 /*
1322                  * If there is a device corresponding to chandle then
1323                  * parse it (depth-first).
1324                  */
1325                 if (acpi_bus_get_device(chandle, &child) == 0) {
1326                         level++;
1327                         phandle = chandle;
1328                         chandle = NULL;
1329                         parent = child;
1330                 }
1331                 continue;
1332         }
1333         return err;
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);