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         kfree(dev->pnp.cid_list);
  32         kfree(dev);
  33 }
  34
  35 struct acpi_device_attribute {
  36         struct attribute attr;
  37          ssize_t(*show) (struct acpi_device *, char *);
  38          ssize_t(*store) (struct acpi_device *, const char *, size_t);
  39 };
  40
  41 typedef void acpi_device_sysfs_files(struct kobject *,
  42                                      const struct attribute *);
  43
  44 static void setup_sys_fs_device_files(struct acpi_device *dev,
  45                                       acpi_device_sysfs_files * func);
  46
  47 #define create_sysfs_device_files(dev)  \
  48         setup_sys_fs_device_files(dev, (acpi_device_sysfs_files *)&sysfs_create_file)
  49 #define remove_sysfs_device_files(dev)  \
  50         setup_sys_fs_device_files(dev, (acpi_device_sysfs_files *)&sysfs_remove_file)
  51
  52 #define to_acpi_device(n) container_of(n, struct acpi_device, kobj)
  53 #define to_handle_attr(n) container_of(n, struct acpi_device_attribute, attr);
  54
  55 static ssize_t acpi_device_attr_show(struct kobject *kobj,
  56                                      struct attribute *attr, char *buf)
  57 {
  58         struct acpi_device *device = to_acpi_device(kobj);
  59         struct acpi_device_attribute *attribute = to_handle_attr(attr);
  60         return attribute->show ? attribute->show(device, buf) : -EIO;
  61 }
  62 static ssize_t acpi_device_attr_store(struct kobject *kobj,
  63                                       struct attribute *attr, const char *buf,
  64                                       size_t len)
  65 {
  66         struct acpi_device *device = to_acpi_device(kobj);
  67         struct acpi_device_attribute *attribute = to_handle_attr(attr);
  68         return attribute->store ? attribute->store(device, buf, len) : -EIO;
  69 }
  70
  71 static struct sysfs_ops acpi_device_sysfs_ops = {
  72         .show = acpi_device_attr_show,
  73         .store = acpi_device_attr_store,
  74 };
  75
  76 static struct kobj_type ktype_acpi_ns = {
  77         .sysfs_ops = &acpi_device_sysfs_ops,
  78         .release = acpi_device_release,
  79 };
  80
  81 static int namespace_uevent(struct kset *kset, struct kobject *kobj,
  82                              char **envp, int num_envp, char *buffer,
  83                              int buffer_size)
  84 {
  85         struct acpi_device *dev = to_acpi_device(kobj);
  86         int i = 0;
  87         int len = 0;
  88
  89         if (!dev->driver)
  90                 return 0;
  91
  92         if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
  93                            "PHYSDEVDRIVER=%s", dev->driver->name))
  94                 return -ENOMEM;
  95
  96         envp[i] = NULL;
  97
  98         return 0;
  99 }
 100
 101 static struct kset_uevent_ops namespace_uevent_ops = {
 102         .uevent = &namespace_uevent,
 103 };
 104
 105 static struct kset acpi_namespace_kset = {
 106         .kobj = {
 107                  .name = "namespace",
 108                  },
 109         .subsys = &acpi_subsys,
 110         .ktype = &ktype_acpi_ns,
 111         .uevent_ops = &namespace_uevent_ops,
 112 };
 113
 114 static void acpi_device_register(struct acpi_device *device,
 115                                  struct acpi_device *parent)
 116 {
 117         /*
 118          * Linkage
 119          * -------
 120          * Link this device to its parent and siblings.
 121          */
 122         INIT_LIST_HEAD(&device->children);
 123         INIT_LIST_HEAD(&device->node);
 124         INIT_LIST_HEAD(&device->g_list);
 125         INIT_LIST_HEAD(&device->wakeup_list);
 126
 127         spin_lock(&acpi_device_lock);
 128         if (device->parent) {
 129                 list_add_tail(&device->node, &device->parent->children);
 130                 list_add_tail(&device->g_list, &device->parent->g_list);
 131         } else
 132                 list_add_tail(&device->g_list, &acpi_device_list);
 133         if (device->wakeup.flags.valid)
 134                 list_add_tail(&device->wakeup_list, &acpi_wakeup_device_list);
 135         spin_unlock(&acpi_device_lock);
 136
 137         strlcpy(device->kobj.name, device->pnp.bus_id, KOBJ_NAME_LEN);
 138         if (parent)
 139                 device->kobj.parent = &parent->kobj;
 140         device->kobj.ktype = &ktype_acpi_ns;
 141         device->kobj.kset = &acpi_namespace_kset;
 142         kobject_register(&device->kobj);
 143         create_sysfs_device_files(device);
 144 }
 145
 146 static int acpi_device_unregister(struct acpi_device *device, int type)
 147 {
 148         spin_lock(&acpi_device_lock);
 149         if (device->parent) {
 150                 list_del(&device->node);
 151                 list_del(&device->g_list);
 152         } else
 153                 list_del(&device->g_list);
 154
 155         list_del(&device->wakeup_list);
 156
 157         spin_unlock(&acpi_device_lock);
 158
 159         acpi_detach_data(device->handle, acpi_bus_data_handler);
 160         remove_sysfs_device_files(device);
 161         kobject_unregister(&device->kobj);
 162         return 0;
 163 }
 164
 165 void acpi_bus_data_handler(acpi_handle handle, u32 function, void *context)
 166 {
 167         ACPI_FUNCTION_TRACE("acpi_bus_data_handler");
 168
 169         /* TBD */
 170
 171         return_VOID;
 172 }
 173
 174 static int acpi_bus_get_power_flags(struct acpi_device *device)
 175 {
 176         acpi_status status = 0;
 177         acpi_handle handle = NULL;
 178         u32 i = 0;
 179
 180         ACPI_FUNCTION_TRACE("acpi_bus_get_power_flags");
 181
 182         /*
 183          * Power Management Flags
 184          */
 185         status = acpi_get_handle(device->handle, "_PSC", &handle);
 186         if (ACPI_SUCCESS(status))
 187                 device->power.flags.explicit_get = 1;
 188         status = acpi_get_handle(device->handle, "_IRC", &handle);
 189         if (ACPI_SUCCESS(status))
 190                 device->power.flags.inrush_current = 1;
 191
 192         /*
 193          * Enumerate supported power management states
 194          */
 195         for (i = ACPI_STATE_D0; i <= ACPI_STATE_D3; i++) {
 196                 struct acpi_device_power_state *ps = &device->power.states[i];
 197                 char object_name[5] = { '_', 'P', 'R', '0' + i, '\0' };
 198
 199                 /* Evaluate "_PRx" to se if power resources are referenced */
 200                 acpi_evaluate_reference(device->handle, object_name, NULL,
 201                                         &ps->resources);
 202                 if (ps->resources.count) {
 203                         device->power.flags.power_resources = 1;
 204                         ps->flags.valid = 1;
 205                 }
 206
 207                 /* Evaluate "_PSx" to see if we can do explicit sets */
 208                 object_name[2] = 'S';
 209                 status = acpi_get_handle(device->handle, object_name, &handle);
 210                 if (ACPI_SUCCESS(status)) {
 211                         ps->flags.explicit_set = 1;
 212                         ps->flags.valid = 1;
 213                 }
 214
 215                 /* State is valid if we have some power control */
 216                 if (ps->resources.count || ps->flags.explicit_set)
 217                         ps->flags.valid = 1;
 218
 219                 ps->power = -1; /* Unknown - driver assigned */
 220                 ps->latency = -1;       /* Unknown - driver assigned */
 221         }
 222
 223         /* Set defaults for D0 and D3 states (always valid) */
 224         device->power.states[ACPI_STATE_D0].flags.valid = 1;
 225         device->power.states[ACPI_STATE_D0].power = 100;
 226         device->power.states[ACPI_STATE_D3].flags.valid = 1;
 227         device->power.states[ACPI_STATE_D3].power = 0;
 228
 229         /* TBD: System wake support and resource requirements. */
 230
 231         device->power.state = ACPI_STATE_UNKNOWN;
 232
 233         return_VALUE(0);
 234 }
 235
 236 int acpi_match_ids(struct acpi_device *device, char *ids)
 237 {
 238         int error = 0;
 239         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 240
 241         if (device->flags.hardware_id)
 242                 if (strstr(ids, device->pnp.hardware_id))
 243                         goto Done;
 244
 245         if (device->flags.compatible_ids) {
 246                 struct acpi_compatible_id_list *cid_list = device->pnp.cid_list;
 247                 int i;
 248
 249                 /* compare multiple _CID entries against driver ids */
 250                 for (i = 0; i < cid_list->count; i++) {
 251                         if (strstr(ids, cid_list->id[i].value))
 252                                 goto Done;
 253                 }
 254         }
 255         error = -ENOENT;
 256
 257       Done:
 258         if (buffer.pointer)
 259                 acpi_os_free(buffer.pointer);
 260         return error;
 261 }
 262
 263 static acpi_status
 264 acpi_bus_extract_wakeup_device_power_package(struct acpi_device *device,
 265                                              union acpi_object *package)
 266 {
 267         int i = 0;
 268         union acpi_object *element = NULL;
 269
 270         if (!device || !package || (package->package.count < 2))
 271                 return AE_BAD_PARAMETER;
 272
 273         element = &(package->package.elements[0]);
 274         if (!element)
 275                 return AE_BAD_PARAMETER;
 276         if (element->type == ACPI_TYPE_PACKAGE) {
 277                 if ((element->package.count < 2) ||
 278                     (element->package.elements[0].type !=
 279                      ACPI_TYPE_LOCAL_REFERENCE)
 280                     || (element->package.elements[1].type != ACPI_TYPE_INTEGER))
 281                         return AE_BAD_DATA;
 282                 device->wakeup.gpe_device =
 283                     element->package.elements[0].reference.handle;
 284                 device->wakeup.gpe_number =
 285                     (u32) element->package.elements[1].integer.value;
 286         } else if (element->type == ACPI_TYPE_INTEGER) {
 287                 device->wakeup.gpe_number = element->integer.value;
 288         } else
 289                 return AE_BAD_DATA;
 290
 291         element = &(package->package.elements[1]);
 292         if (element->type != ACPI_TYPE_INTEGER) {
 293                 return AE_BAD_DATA;
 294         }
 295         device->wakeup.sleep_state = element->integer.value;
 296
 297         if ((package->package.count - 2) > ACPI_MAX_HANDLES) {
 298                 return AE_NO_MEMORY;
 299         }
 300         device->wakeup.resources.count = package->package.count - 2;
 301         for (i = 0; i < device->wakeup.resources.count; i++) {
 302                 element = &(package->package.elements[i + 2]);
 303                 if (element->type != ACPI_TYPE_ANY) {
 304                         return AE_BAD_DATA;
 305                 }
 306
 307                 device->wakeup.resources.handles[i] = element->reference.handle;
 308         }
 309
 310         return AE_OK;
 311 }
 312
 313 static int acpi_bus_get_wakeup_device_flags(struct acpi_device *device)
 314 {
 315         acpi_status status = 0;
 316         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 317         union acpi_object *package = NULL;
 318
 319         ACPI_FUNCTION_TRACE("acpi_bus_get_wakeup_flags");
 320
 321         /* _PRW */
 322         status = acpi_evaluate_object(device->handle, "_PRW", NULL, &buffer);
 323         if (ACPI_FAILURE(status)) {
 324                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _PRW\n"));
 325                 goto end;
 326         }
 327
 328         package = (union acpi_object *)buffer.pointer;
 329         status = acpi_bus_extract_wakeup_device_power_package(device, package);
 330         if (ACPI_FAILURE(status)) {
 331                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 332                                   "Error extracting _PRW package\n"));
 333                 goto end;
 334         }
 335
 336         acpi_os_free(buffer.pointer);
 337
 338         device->wakeup.flags.valid = 1;
 339         /* Power button, Lid switch always enable wakeup */
 340         if (!acpi_match_ids(device, "PNP0C0D,PNP0C0C,PNP0C0E"))
 341                 device->wakeup.flags.run_wake = 1;
 342
 343       end:
 344         if (ACPI_FAILURE(status))
 345                 device->flags.wake_capable = 0;
 346         return_VALUE(0);
 347 }
 348
 349 /* --------------------------------------------------------------------------
 350                 ACPI sysfs device file support
 351    -------------------------------------------------------------------------- */
 352 static ssize_t acpi_eject_store(struct acpi_device *device,
 353                                 const char *buf, size_t count);
 354
 355 #define ACPI_DEVICE_ATTR(_name,_mode,_show,_store) \
 356 static struct acpi_device_attribute acpi_device_attr_##_name = \
 357                 __ATTR(_name, _mode, _show, _store)
 358
 359 ACPI_DEVICE_ATTR(eject, 0200, NULL, acpi_eject_store);
 360
 361 /**
 362  * setup_sys_fs_device_files - sets up the device files under device namespace
 363  * @dev:        acpi_device object
 364  * @func:       function pointer to create or destroy the device file
 365  */
 366 static void
 367 setup_sys_fs_device_files(struct acpi_device *dev,
 368                           acpi_device_sysfs_files * func)
 369 {
 370         acpi_status status;
 371         acpi_handle temp = NULL;
 372
 373         /*
 374          * If device has _EJ0, 'eject' file is created that is used to trigger
 375          * hot-removal function from userland.
 376          */
 377         status = acpi_get_handle(dev->handle, "_EJ0", &temp);
 378         if (ACPI_SUCCESS(status))
 379                 (*(func)) (&dev->kobj, &acpi_device_attr_eject.attr);
 380 }
 381
 382 static int acpi_eject_operation(acpi_handle handle, int lockable)
 383 {
 384         struct acpi_object_list arg_list;
 385         union acpi_object arg;
 386         acpi_status status = AE_OK;
 387
 388         /*
 389          * TBD: evaluate _PS3?
 390          */
 391
 392         if (lockable) {
 393                 arg_list.count = 1;
 394                 arg_list.pointer = &arg;
 395                 arg.type = ACPI_TYPE_INTEGER;
 396                 arg.integer.value = 0;
 397                 acpi_evaluate_object(handle, "_LCK", &arg_list, NULL);
 398         }
 399
 400         arg_list.count = 1;
 401         arg_list.pointer = &arg;
 402         arg.type = ACPI_TYPE_INTEGER;
 403         arg.integer.value = 1;
 404
 405         /*
 406          * TBD: _EJD support.
 407          */
 408
 409         status = acpi_evaluate_object(handle, "_EJ0", &arg_list, NULL);
 410         if (ACPI_FAILURE(status)) {
 411                 return (-ENODEV);
 412         }
 413
 414         return (0);
 415 }
 416
 417 static ssize_t
 418 acpi_eject_store(struct acpi_device *device, const char *buf, size_t count)
 419 {
 420         int result;
 421         int ret = count;
 422         int islockable;
 423         acpi_status status;
 424         acpi_handle handle;
 425         acpi_object_type type = 0;
 426
 427         if ((!count) || (buf[0] != '1')) {
 428                 return -EINVAL;
 429         }
 430 #ifndef FORCE_EJECT
 431         if (device->driver == NULL) {
 432                 ret = -ENODEV;
 433                 goto err;
 434         }
 435 #endif
 436         status = acpi_get_type(device->handle, &type);
 437         if (ACPI_FAILURE(status) || (!device->flags.ejectable)) {
 438                 ret = -ENODEV;
 439                 goto err;
 440         }
 441
 442         islockable = device->flags.lockable;
 443         handle = device->handle;
 444
 445         if (type == ACPI_TYPE_PROCESSOR)
 446                 result = acpi_bus_trim(device, 0);
 447         else
 448                 result = acpi_bus_trim(device, 1);
 449
 450         if (!result)
 451                 result = acpi_eject_operation(handle, islockable);
 452
 453         if (result) {
 454                 ret = -EBUSY;
 455         }
 456       err:
 457         return ret;
 458 }
 459
 460 /* --------------------------------------------------------------------------
 461                               Performance Management
 462    -------------------------------------------------------------------------- */
 463
 464 static int acpi_bus_get_perf_flags(struct acpi_device *device)
 465 {
 466         device->performance.state = ACPI_STATE_UNKNOWN;
 467         return 0;
 468 }
 469
 470 /* --------------------------------------------------------------------------
 471                                  Driver Management
 472    -------------------------------------------------------------------------- */
 473
 474 static LIST_HEAD(acpi_bus_drivers);
 475 static DECLARE_MUTEX(acpi_bus_drivers_lock);
 476
 477 /**
 478  * acpi_bus_match - match device IDs to driver's supported IDs
 479  * @device: the device that we are trying to match to a driver
 480  * @driver: driver whose device id table is being checked
 481  *
 482  * Checks the device's hardware (_HID) or compatible (_CID) ids to see if it
 483  * matches the specified driver's criteria.
 484  */
 485 static int
 486 acpi_bus_match(struct acpi_device *device, struct acpi_driver *driver)
 487 {
 488         if (driver && driver->ops.match)
 489                 return driver->ops.match(device, driver);
 490         return acpi_match_ids(device, driver->ids);
 491 }
 492
 493 /**
 494  * acpi_bus_driver_init - add a device to a driver
 495  * @device: the device to add and initialize
 496  * @driver: driver for the device
 497  *
 498  * Used to initialize a device via its device driver.  Called whenever a
 499  * driver is bound to a device.  Invokes the driver's add() and start() ops.
 500  */
 501 static int
 502 acpi_bus_driver_init(struct acpi_device *device, struct acpi_driver *driver)
 503 {
 504         int result = 0;
 505
 506         ACPI_FUNCTION_TRACE("acpi_bus_driver_init");
 507
 508         if (!device || !driver)
 509                 return_VALUE(-EINVAL);
 510
 511         if (!driver->ops.add)
 512                 return_VALUE(-ENOSYS);
 513
 514         result = driver->ops.add(device);
 515         if (result) {
 516                 device->driver = NULL;
 517                 acpi_driver_data(device) = NULL;
 518                 return_VALUE(result);
 519         }
 520
 521         device->driver = driver;
 522
 523         /*
 524          * TBD - Configuration Management: Assign resources to device based
 525          * upon possible configuration and currently allocated resources.
 526          */
 527
 528         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 529                           "Driver successfully bound to device\n"));
 530         return_VALUE(0);
 531 }
 532
 533 static int acpi_start_single_object(struct acpi_device *device)
 534 {
 535         int result = 0;
 536         struct acpi_driver *driver;
 537
 538         ACPI_FUNCTION_TRACE("acpi_start_single_object");
 539
 540         if (!(driver = device->driver))
 541                 return_VALUE(0);
 542
 543         if (driver->ops.start) {
 544                 result = driver->ops.start(device);
 545                 if (result && driver->ops.remove)
 546                         driver->ops.remove(device, ACPI_BUS_REMOVAL_NORMAL);
 547         }
 548
 549         return_VALUE(result);
 550 }
 551
 552 static int acpi_driver_attach(struct acpi_driver *drv)
 553 {
 554         struct list_head *node, *next;
 555         int count = 0;
 556
 557         ACPI_FUNCTION_TRACE("acpi_driver_attach");
 558
 559         spin_lock(&acpi_device_lock);
 560         list_for_each_safe(node, next, &acpi_device_list) {
 561                 struct acpi_device *dev =
 562                     container_of(node, struct acpi_device, g_list);
 563
 564                 if (dev->driver || !dev->status.present)
 565                         continue;
 566                 spin_unlock(&acpi_device_lock);
 567
 568                 if (!acpi_bus_match(dev, drv)) {
 569                         if (!acpi_bus_driver_init(dev, drv)) {
 570                                 acpi_start_single_object(dev);
 571                                 atomic_inc(&drv->references);
 572                                 count++;
 573                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 574                                                   "Found driver [%s] for device [%s]\n",
 575                                                   drv->name, dev->pnp.bus_id));
 576                         }
 577                 }
 578                 spin_lock(&acpi_device_lock);
 579         }
 580         spin_unlock(&acpi_device_lock);
 581         return_VALUE(count);
 582 }
 583
 584 static int acpi_driver_detach(struct acpi_driver *drv)
 585 {
 586         struct list_head *node, *next;
 587
 588         ACPI_FUNCTION_TRACE("acpi_driver_detach");
 589
 590         spin_lock(&acpi_device_lock);
 591         list_for_each_safe(node, next, &acpi_device_list) {
 592                 struct acpi_device *dev =
 593                     container_of(node, struct acpi_device, g_list);
 594
 595                 if (dev->driver == drv) {
 596                         spin_unlock(&acpi_device_lock);
 597                         if (drv->ops.remove)
 598                                 drv->ops.remove(dev, ACPI_BUS_REMOVAL_NORMAL);
 599                         spin_lock(&acpi_device_lock);
 600                         dev->driver = NULL;
 601                         dev->driver_data = NULL;
 602                         atomic_dec(&drv->references);
 603                 }
 604         }
 605         spin_unlock(&acpi_device_lock);
 606         return_VALUE(0);
 607 }
 608
 609 /**
 610  * acpi_bus_register_driver - register a driver with the ACPI bus
 611  * @driver: driver being registered
 612  *
 613  * Registers a driver with the ACPI bus.  Searches the namespace for all
 614  * devices that match the driver's criteria and binds.  Returns the
 615  * number of devices that were claimed by the driver, or a negative
 616  * error status for failure.
 617  */
 618 int acpi_bus_register_driver(struct acpi_driver *driver)
 619 {
 620         int count;
 621
 622         ACPI_FUNCTION_TRACE("acpi_bus_register_driver");
 623
 624         if (acpi_disabled)
 625                 return_VALUE(-ENODEV);
 626
 627         if (!driver)
 628                 return_VALUE(-EINVAL);
 629
 630         spin_lock(&acpi_device_lock);
 631         list_add_tail(&driver->node, &acpi_bus_drivers);
 632         spin_unlock(&acpi_device_lock);
 633         count = acpi_driver_attach(driver);
 634
 635         return_VALUE(count);
 636 }
 637
 638 EXPORT_SYMBOL(acpi_bus_register_driver);
 639
 640 /**
 641  * acpi_bus_unregister_driver - unregisters a driver with the APIC bus
 642  * @driver: driver to unregister
 643  *
 644  * Unregisters a driver with the ACPI bus.  Searches the namespace for all
 645  * devices that match the driver's criteria and unbinds.
 646  */
 647 int acpi_bus_unregister_driver(struct acpi_driver *driver)
 648 {
 649         int error = 0;
 650
 651         ACPI_FUNCTION_TRACE("acpi_bus_unregister_driver");
 652
 653         if (driver) {
 654                 acpi_driver_detach(driver);
 655
 656                 if (!atomic_read(&driver->references)) {
 657                         spin_lock(&acpi_device_lock);
 658                         list_del_init(&driver->node);
 659                         spin_unlock(&acpi_device_lock);
 660                 }
 661         } else
 662                 error = -EINVAL;
 663         return_VALUE(error);
 664 }
 665
 666 EXPORT_SYMBOL(acpi_bus_unregister_driver);
 667
 668 /**
 669  * acpi_bus_find_driver - check if there is a driver installed for the device
 670  * @device: device that we are trying to find a supporting driver for
 671  *
 672  * Parses the list of registered drivers looking for a driver applicable for
 673  * the specified device.
 674  */
 675 static int acpi_bus_find_driver(struct acpi_device *device)
 676 {
 677         int result = 0;
 678         struct list_head *node, *next;
 679
 680         ACPI_FUNCTION_TRACE("acpi_bus_find_driver");
 681
 682         spin_lock(&acpi_device_lock);
 683         list_for_each_safe(node, next, &acpi_bus_drivers) {
 684                 struct acpi_driver *driver =
 685                     container_of(node, struct acpi_driver, node);
 686
 687                 atomic_inc(&driver->references);
 688                 spin_unlock(&acpi_device_lock);
 689                 if (!acpi_bus_match(device, driver)) {
 690                         result = acpi_bus_driver_init(device, driver);
 691                         if (!result)
 692                                 goto Done;
 693                 }
 694                 atomic_dec(&driver->references);
 695                 spin_lock(&acpi_device_lock);
 696         }
 697         spin_unlock(&acpi_device_lock);
 698
 699       Done:
 700         return_VALUE(result);
 701 }
 702
 703 /* --------------------------------------------------------------------------
 704                                  Device Enumeration
 705    -------------------------------------------------------------------------- */
 706
 707 static int acpi_bus_get_flags(struct acpi_device *device)
 708 {
 709         acpi_status status = AE_OK;
 710         acpi_handle temp = NULL;
 711
 712         ACPI_FUNCTION_TRACE("acpi_bus_get_flags");
 713
 714         /* Presence of _STA indicates 'dynamic_status' */
 715         status = acpi_get_handle(device->handle, "_STA", &temp);
 716         if (ACPI_SUCCESS(status))
 717                 device->flags.dynamic_status = 1;
 718
 719         /* Presence of _CID indicates 'compatible_ids' */
 720         status = acpi_get_handle(device->handle, "_CID", &temp);
 721         if (ACPI_SUCCESS(status))
 722                 device->flags.compatible_ids = 1;
 723
 724         /* Presence of _RMV indicates 'removable' */
 725         status = acpi_get_handle(device->handle, "_RMV", &temp);
 726         if (ACPI_SUCCESS(status))
 727                 device->flags.removable = 1;
 728
 729         /* Presence of _EJD|_EJ0 indicates 'ejectable' */
 730         status = acpi_get_handle(device->handle, "_EJD", &temp);
 731         if (ACPI_SUCCESS(status))
 732                 device->flags.ejectable = 1;
 733         else {
 734                 status = acpi_get_handle(device->handle, "_EJ0", &temp);
 735                 if (ACPI_SUCCESS(status))
 736                         device->flags.ejectable = 1;
 737         }
 738
 739         /* Presence of _LCK indicates 'lockable' */
 740         status = acpi_get_handle(device->handle, "_LCK", &temp);
 741         if (ACPI_SUCCESS(status))
 742                 device->flags.lockable = 1;
 743
 744         /* Presence of _PS0|_PR0 indicates 'power manageable' */
 745         status = acpi_get_handle(device->handle, "_PS0", &temp);
 746         if (ACPI_FAILURE(status))
 747                 status = acpi_get_handle(device->handle, "_PR0", &temp);
 748         if (ACPI_SUCCESS(status))
 749                 device->flags.power_manageable = 1;
 750
 751         /* Presence of _PRW indicates wake capable */
 752         status = acpi_get_handle(device->handle, "_PRW", &temp);
 753         if (ACPI_SUCCESS(status))
 754                 device->flags.wake_capable = 1;
 755
 756         /* TBD: Peformance management */
 757
 758         return_VALUE(0);
 759 }
 760
 761 static void acpi_device_get_busid(struct acpi_device *device,
 762                                   acpi_handle handle, int type)
 763 {
 764         char bus_id[5] = { '?', 0 };
 765         struct acpi_buffer buffer = { sizeof(bus_id), bus_id };
 766         int i = 0;
 767
 768         /*
 769          * Bus ID
 770          * ------
 771          * The device's Bus ID is simply the object name.
 772          * TBD: Shouldn't this value be unique (within the ACPI namespace)?
 773          */
 774         switch (type) {
 775         case ACPI_BUS_TYPE_SYSTEM:
 776                 strcpy(device->pnp.bus_id, "ACPI");
 777                 break;
 778         case ACPI_BUS_TYPE_POWER_BUTTON:
 779                 strcpy(device->pnp.bus_id, "PWRF");
 780                 break;
 781         case ACPI_BUS_TYPE_SLEEP_BUTTON:
 782                 strcpy(device->pnp.bus_id, "SLPF");
 783                 break;
 784         default:
 785                 acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
 786                 /* Clean up trailing underscores (if any) */
 787                 for (i = 3; i > 1; i--) {
 788                         if (bus_id[i] == '_')
 789                                 bus_id[i] = '\0';
 790                         else
 791                                 break;
 792                 }
 793                 strcpy(device->pnp.bus_id, bus_id);
 794                 break;
 795         }
 796 }
 797
 798 static void acpi_device_set_id(struct acpi_device *device,
 799                                struct acpi_device *parent, acpi_handle handle,
 800                                int type)
 801 {
 802         struct acpi_device_info *info;
 803         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 804         char *hid = NULL;
 805         char *uid = NULL;
 806         struct acpi_compatible_id_list *cid_list = NULL;
 807         acpi_status status;
 808
 809         switch (type) {
 810         case ACPI_BUS_TYPE_DEVICE:
 811                 status = acpi_get_object_info(handle, &buffer);
 812                 if (ACPI_FAILURE(status)) {
 813                         printk("%s: Error reading device info\n", __FUNCTION__);
 814                         return;
 815                 }
 816
 817                 info = buffer.pointer;
 818                 if (info->valid & ACPI_VALID_HID)
 819                         hid = info->hardware_id.value;
 820                 if (info->valid & ACPI_VALID_UID)
 821                         uid = info->unique_id.value;
 822                 if (info->valid & ACPI_VALID_CID)
 823                         cid_list = &info->compatibility_id;
 824                 if (info->valid & ACPI_VALID_ADR) {
 825                         device->pnp.bus_address = info->address;
 826                         device->flags.bus_address = 1;
 827                 }
 828                 break;
 829         case ACPI_BUS_TYPE_POWER:
 830                 hid = ACPI_POWER_HID;
 831                 break;
 832         case ACPI_BUS_TYPE_PROCESSOR:
 833                 hid = ACPI_PROCESSOR_HID;
 834                 break;
 835         case ACPI_BUS_TYPE_SYSTEM:
 836                 hid = ACPI_SYSTEM_HID;
 837                 break;
 838         case ACPI_BUS_TYPE_THERMAL:
 839                 hid = ACPI_THERMAL_HID;
 840                 break;
 841         case ACPI_BUS_TYPE_POWER_BUTTON:
 842                 hid = ACPI_BUTTON_HID_POWERF;
 843                 break;
 844         case ACPI_BUS_TYPE_SLEEP_BUTTON:
 845                 hid = ACPI_BUTTON_HID_SLEEPF;
 846                 break;
 847         }
 848
 849         /*
 850          * \_SB
 851          * ----
 852          * Fix for the system root bus device -- the only root-level device.
 853          */
 854         if ((parent == ACPI_ROOT_OBJECT) && (type == ACPI_BUS_TYPE_DEVICE)) {
 855                 hid = ACPI_BUS_HID;
 856                 strcpy(device->pnp.device_name, ACPI_BUS_DEVICE_NAME);
 857                 strcpy(device->pnp.device_class, ACPI_BUS_CLASS);
 858         }
 859
 860         if (hid) {
 861                 strcpy(device->pnp.hardware_id, hid);
 862                 device->flags.hardware_id = 1;
 863         }
 864         if (uid) {
 865                 strcpy(device->pnp.unique_id, uid);
 866                 device->flags.unique_id = 1;
 867         }
 868         if (cid_list) {
 869                 device->pnp.cid_list = kmalloc(cid_list->size, GFP_KERNEL);
 870                 if (device->pnp.cid_list)
 871                         memcpy(device->pnp.cid_list, cid_list, cid_list->size);
 872                 else
 873                         printk(KERN_ERR "Memory allocation error\n");
 874         }
 875
 876         acpi_os_free(buffer.pointer);
 877 }
 878
 879 static int acpi_device_set_context(struct acpi_device *device, int type)
 880 {
 881         acpi_status status = AE_OK;
 882         int result = 0;
 883         /*
 884          * Context
 885          * -------
 886          * Attach this 'struct acpi_device' to the ACPI object.  This makes
 887          * resolutions from handle->device very efficient.  Note that we need
 888          * to be careful with fixed-feature devices as they all attach to the
 889          * root object.
 890          */
 891         if (type != ACPI_BUS_TYPE_POWER_BUTTON &&
 892             type != ACPI_BUS_TYPE_SLEEP_BUTTON) {
 893                 status = acpi_attach_data(device->handle,
 894                                           acpi_bus_data_handler, device);
 895
 896                 if (ACPI_FAILURE(status)) {
 897                         printk("Error attaching device data\n");
 898                         result = -ENODEV;
 899                 }
 900         }
 901         return result;
 902 }
 903
 904 static void acpi_device_get_debug_info(struct acpi_device *device,
 905                                        acpi_handle handle, int type)
 906 {
 907 #ifdef CONFIG_ACPI_DEBUG_OUTPUT
 908         char *type_string = NULL;
 909         char name[80] = { '?', '\0' };
 910         struct acpi_buffer buffer = { sizeof(name), name };
 911
 912         switch (type) {
 913         case ACPI_BUS_TYPE_DEVICE:
 914                 type_string = "Device";
 915                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 916                 break;
 917         case ACPI_BUS_TYPE_POWER:
 918                 type_string = "Power Resource";
 919                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 920                 break;
 921         case ACPI_BUS_TYPE_PROCESSOR:
 922                 type_string = "Processor";
 923                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 924                 break;
 925         case ACPI_BUS_TYPE_SYSTEM:
 926                 type_string = "System";
 927                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 928                 break;
 929         case ACPI_BUS_TYPE_THERMAL:
 930                 type_string = "Thermal Zone";
 931                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 932                 break;
 933         case ACPI_BUS_TYPE_POWER_BUTTON:
 934                 type_string = "Power Button";
 935                 sprintf(name, "PWRB");
 936                 break;
 937         case ACPI_BUS_TYPE_SLEEP_BUTTON:
 938                 type_string = "Sleep Button";
 939                 sprintf(name, "SLPB");
 940                 break;
 941         }
 942
 943         printk(KERN_DEBUG "Found %s %s [%p]\n", type_string, name, handle);
 944 #endif                          /*CONFIG_ACPI_DEBUG_OUTPUT */
 945 }
 946
 947 static int acpi_bus_remove(struct acpi_device *dev, int rmdevice)
 948 {
 949         int result = 0;
 950         struct acpi_driver *driver;
 951
 952         ACPI_FUNCTION_TRACE("acpi_bus_remove");
 953
 954         if (!dev)
 955                 return_VALUE(-EINVAL);
 956
 957         driver = dev->driver;
 958
 959         if ((driver) && (driver->ops.remove)) {
 960
 961                 if (driver->ops.stop) {
 962                         result = driver->ops.stop(dev, ACPI_BUS_REMOVAL_EJECT);
 963                         if (result)
 964                                 return_VALUE(result);
 965                 }
 966
 967                 result = dev->driver->ops.remove(dev, ACPI_BUS_REMOVAL_EJECT);
 968                 if (result) {
 969                         return_VALUE(result);
 970                 }
 971
 972                 atomic_dec(&dev->driver->references);
 973                 dev->driver = NULL;
 974                 acpi_driver_data(dev) = NULL;
 975         }
 976
 977         if (!rmdevice)
 978                 return_VALUE(0);
 979
 980         if (dev->flags.bus_address) {
 981                 if ((dev->parent) && (dev->parent->ops.unbind))
 982                         dev->parent->ops.unbind(dev);
 983         }
 984
 985         acpi_device_unregister(dev, ACPI_BUS_REMOVAL_EJECT);
 986
 987         return_VALUE(0);
 988 }
 989
 990 static int
 991 acpi_add_single_object(struct acpi_device **child,
 992                        struct acpi_device *parent, acpi_handle handle, int type)
 993 {
 994         int result = 0;
 995         struct acpi_device *device = NULL;
 996
 997         ACPI_FUNCTION_TRACE("acpi_add_single_object");
 998
 999         if (!child)
1000                 return_VALUE(-EINVAL);
1001
1002         device = kmalloc(sizeof(struct acpi_device), GFP_KERNEL);
1003         if (!device) {
1004                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Memory allocation error\n"));
1005                 return_VALUE(-ENOMEM);
1006         }
1007         memset(device, 0, sizeof(struct acpi_device));
1008
1009         device->handle = handle;
1010         device->parent = parent;
1011
1012         acpi_device_get_busid(device, handle, type);
1013
1014         /*
1015          * Flags
1016          * -----
1017          * Get prior to calling acpi_bus_get_status() so we know whether
1018          * or not _STA is present.  Note that we only look for object
1019          * handles -- cannot evaluate objects until we know the device is
1020          * present and properly initialized.
1021          */
1022         result = acpi_bus_get_flags(device);
1023         if (result)
1024                 goto end;
1025
1026         /*
1027          * Status
1028          * ------
1029          * See if the device is present.  We always assume that non-Device
1030          * and non-Processor objects (e.g. thermal zones, power resources,
1031          * etc.) are present, functioning, etc. (at least when parent object
1032          * is present).  Note that _STA has a different meaning for some
1033          * objects (e.g. power resources) so we need to be careful how we use
1034          * it.
1035          */
1036         switch (type) {
1037         case ACPI_BUS_TYPE_PROCESSOR:
1038         case ACPI_BUS_TYPE_DEVICE:
1039                 result = acpi_bus_get_status(device);
1040                 if (ACPI_FAILURE(result) || !device->status.present) {
1041                         result = -ENOENT;
1042                         goto end;
1043                 }
1044                 break;
1045         default:
1046                 STRUCT_TO_INT(device->status) = 0x0F;
1047                 break;
1048         }
1049
1050         /*
1051          * Initialize Device
1052          * -----------------
1053          * TBD: Synch with Core's enumeration/initialization process.
1054          */
1055
1056         /*
1057          * Hardware ID, Unique ID, & Bus Address
1058          * -------------------------------------
1059          */
1060         acpi_device_set_id(device, parent, handle, type);
1061
1062         /*
1063          * Power Management
1064          * ----------------
1065          */
1066         if (device->flags.power_manageable) {
1067                 result = acpi_bus_get_power_flags(device);
1068                 if (result)
1069                         goto end;
1070         }
1071
1072         /*
1073          * Wakeup device management
1074          *-----------------------
1075          */
1076         if (device->flags.wake_capable) {
1077                 result = acpi_bus_get_wakeup_device_flags(device);
1078                 if (result)
1079                         goto end;
1080         }
1081
1082         /*
1083          * Performance Management
1084          * ----------------------
1085          */
1086         if (device->flags.performance_manageable) {
1087                 result = acpi_bus_get_perf_flags(device);
1088                 if (result)
1089                         goto end;
1090         }
1091
1092         if ((result = acpi_device_set_context(device, type)))
1093                 goto end;
1094
1095         acpi_device_get_debug_info(device, handle, type);
1096
1097         acpi_device_register(device, parent);
1098
1099         /*
1100          * Bind _ADR-Based Devices
1101          * -----------------------
1102          * If there's a a bus address (_ADR) then we utilize the parent's
1103          * 'bind' function (if exists) to bind the ACPI- and natively-
1104          * enumerated device representations.
1105          */
1106         if (device->flags.bus_address) {
1107                 if (device->parent && device->parent->ops.bind)
1108                         device->parent->ops.bind(device);
1109         }
1110
1111         /*
1112          * Locate & Attach Driver
1113          * ----------------------
1114          * If there's a hardware id (_HID) or compatible ids (_CID) we check
1115          * to see if there's a driver installed for this kind of device.  Note
1116          * that drivers can install before or after a device is enumerated.
1117          *
1118          * TBD: Assumes LDM provides driver hot-plug capability.
1119          */
1120         acpi_bus_find_driver(device);
1121
1122       end:
1123         if (!result)
1124                 *child = device;
1125         else {
1126                 kfree(device->pnp.cid_list);
1127                 kfree(device);
1128         }
1129
1130         return_VALUE(result);
1131 }
1132
1133 static int acpi_bus_scan(struct acpi_device *start, struct acpi_bus_ops *ops)
1134 {
1135         acpi_status status = AE_OK;
1136         struct acpi_device *parent = NULL;
1137         struct acpi_device *child = NULL;
1138         acpi_handle phandle = NULL;
1139         acpi_handle chandle = NULL;
1140         acpi_object_type type = 0;
1141         u32 level = 1;
1142
1143         ACPI_FUNCTION_TRACE("acpi_bus_scan");
1144
1145         if (!start)
1146                 return_VALUE(-EINVAL);
1147
1148         parent = start;
1149         phandle = start->handle;
1150
1151         /*
1152          * Parse through the ACPI namespace, identify all 'devices', and
1153          * create a new 'struct acpi_device' for each.
1154          */
1155         while ((level > 0) && parent) {
1156
1157                 status = acpi_get_next_object(ACPI_TYPE_ANY, phandle,
1158                                               chandle, &chandle);
1159
1160                 /*
1161                  * If this scope is exhausted then move our way back up.
1162                  */
1163                 if (ACPI_FAILURE(status)) {
1164                         level--;
1165                         chandle = phandle;
1166                         acpi_get_parent(phandle, &phandle);
1167                         if (parent->parent)
1168                                 parent = parent->parent;
1169                         continue;
1170                 }
1171
1172                 status = acpi_get_type(chandle, &type);
1173                 if (ACPI_FAILURE(status))
1174                         continue;
1175
1176                 /*
1177                  * If this is a scope object then parse it (depth-first).
1178                  */
1179                 if (type == ACPI_TYPE_LOCAL_SCOPE) {
1180                         level++;
1181                         phandle = chandle;
1182                         chandle = NULL;
1183                         continue;
1184                 }
1185
1186                 /*
1187                  * We're only interested in objects that we consider 'devices'.
1188                  */
1189                 switch (type) {
1190                 case ACPI_TYPE_DEVICE:
1191                         type = ACPI_BUS_TYPE_DEVICE;
1192                         break;
1193                 case ACPI_TYPE_PROCESSOR:
1194                         type = ACPI_BUS_TYPE_PROCESSOR;
1195                         break;
1196                 case ACPI_TYPE_THERMAL:
1197                         type = ACPI_BUS_TYPE_THERMAL;
1198                         break;
1199                 case ACPI_TYPE_POWER:
1200                         type = ACPI_BUS_TYPE_POWER;
1201                         break;
1202                 default:
1203                         continue;
1204                 }
1205
1206                 if (ops->acpi_op_add)
1207                         status = acpi_add_single_object(&child, parent,
1208                                                         chandle, type);
1209                 else
1210                         status = acpi_bus_get_device(chandle, &child);
1211
1212                 if (ACPI_FAILURE(status))
1213                         continue;
1214
1215                 if (ops->acpi_op_start) {
1216                         status = acpi_start_single_object(child);
1217                         if (ACPI_FAILURE(status))
1218                                 continue;
1219                 }
1220
1221                 /*
1222                  * If the device is present, enabled, and functioning then
1223                  * parse its scope (depth-first).  Note that we need to
1224                  * represent absent devices to facilitate PnP notifications
1225                  * -- but only the subtree head (not all of its children,
1226                  * which will be enumerated when the parent is inserted).
1227                  *
1228                  * TBD: Need notifications and other detection mechanisms
1229                  *      in place before we can fully implement this.
1230                  */
1231                 if (child->status.present) {
1232                         status = acpi_get_next_object(ACPI_TYPE_ANY, chandle,
1233                                                       NULL, NULL);
1234                         if (ACPI_SUCCESS(status)) {
1235                                 level++;
1236                                 phandle = chandle;
1237                                 chandle = NULL;
1238                                 parent = child;
1239                         }
1240                 }
1241         }
1242
1243         return_VALUE(0);
1244 }
1245
1246 int
1247 acpi_bus_add(struct acpi_device **child,
1248              struct acpi_device *parent, acpi_handle handle, int type)
1249 {
1250         int result;
1251         struct acpi_bus_ops ops;
1252
1253         ACPI_FUNCTION_TRACE("acpi_bus_add");
1254
1255         result = acpi_add_single_object(child, parent, handle, type);
1256         if (!result) {
1257                 memset(&ops, 0, sizeof(ops));
1258                 ops.acpi_op_add = 1;
1259                 result = acpi_bus_scan(*child, &ops);
1260         }
1261         return_VALUE(result);
1262 }
1263
1264 EXPORT_SYMBOL(acpi_bus_add);
1265
1266 int acpi_bus_start(struct acpi_device *device)
1267 {
1268         int result;
1269         struct acpi_bus_ops ops;
1270
1271         ACPI_FUNCTION_TRACE("acpi_bus_start");
1272
1273         if (!device)
1274                 return_VALUE(-EINVAL);
1275
1276         result = acpi_start_single_object(device);
1277         if (!result) {
1278                 memset(&ops, 0, sizeof(ops));
1279                 ops.acpi_op_start = 1;
1280                 result = acpi_bus_scan(device, &ops);
1281         }
1282         return_VALUE(result);
1283 }
1284
1285 EXPORT_SYMBOL(acpi_bus_start);
1286
1287 static int acpi_bus_trim(struct acpi_device *start, int rmdevice)
1288 {
1289         acpi_status status;
1290         struct acpi_device *parent, *child;
1291         acpi_handle phandle, chandle;
1292         acpi_object_type type;
1293         u32 level = 1;
1294         int err = 0;
1295
1296         parent = start;
1297         phandle = start->handle;
1298         child = chandle = NULL;
1299
1300         while ((level > 0) && parent && (!err)) {
1301                 status = acpi_get_next_object(ACPI_TYPE_ANY, phandle,
1302                                               chandle, &chandle);
1303
1304                 /*
1305                  * If this scope is exhausted then move our way back up.
1306                  */
1307                 if (ACPI_FAILURE(status)) {
1308                         level--;
1309                         chandle = phandle;
1310                         acpi_get_parent(phandle, &phandle);
1311                         child = parent;
1312                         parent = parent->parent;
1313
1314                         if (level == 0)
1315                                 err = acpi_bus_remove(child, rmdevice);
1316                         else
1317                                 err = acpi_bus_remove(child, 1);
1318
1319                         continue;
1320                 }
1321
1322                 status = acpi_get_type(chandle, &type);
1323                 if (ACPI_FAILURE(status)) {
1324                         continue;
1325                 }
1326                 /*
1327                  * If there is a device corresponding to chandle then
1328                  * parse it (depth-first).
1329                  */
1330                 if (acpi_bus_get_device(chandle, &child) == 0) {
1331                         level++;
1332                         phandle = chandle;
1333                         chandle = NULL;
1334                         parent = child;
1335                 }
1336                 continue;
1337         }
1338         return err;
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);