drivers/acpi/scan.c

   1 /*
   2  * scan.c - support for transforming the ACPI namespace into individual objects
   3  */
   4
   5 #include <linux/module.h>
   6 #include <linux/init.h>
   7 #include <linux/acpi.h>
   8
   9 #include <acpi/acpi_drivers.h>
  10 #include <acpi/acinterp.h>      /* for acpi_ex_eisa_id_to_string() */
  11
  12 #define _COMPONENT              ACPI_BUS_COMPONENT
  13 ACPI_MODULE_NAME("scan")
  14 #define STRUCT_TO_INT(s)        (*((int*)&s))
  15 extern struct acpi_device *acpi_root;
  16
  17 #define ACPI_BUS_CLASS                  "system_bus"
  18 #define ACPI_BUS_HID                    "ACPI_BUS"
  19 #define ACPI_BUS_DRIVER_NAME            "ACPI Bus Driver"
  20 #define ACPI_BUS_DEVICE_NAME            "System Bus"
  21
  22 static LIST_HEAD(acpi_device_list);
  23 DEFINE_SPINLOCK(acpi_device_lock);
  24 LIST_HEAD(acpi_wakeup_device_list);
  25
  26
  27 static void acpi_device_release(struct kobject *kobj)
  28 {
  29         struct acpi_device *dev = container_of(kobj, struct acpi_device, kobj);
  30         kfree(dev->pnp.cid_list);
  31         kfree(dev);
  32 }
  33
  34 struct acpi_device_attribute {
  35         struct attribute attr;
  36          ssize_t(*show) (struct acpi_device *, char *);
  37          ssize_t(*store) (struct acpi_device *, const char *, size_t);
  38 };
  39
  40 typedef void acpi_device_sysfs_files(struct kobject *,
  41                                      const struct attribute *);
  42
  43 static void setup_sys_fs_device_files(struct acpi_device *dev,
  44                                       acpi_device_sysfs_files * func);
  45
  46 #define create_sysfs_device_files(dev)  \
  47         setup_sys_fs_device_files(dev, (acpi_device_sysfs_files *)&sysfs_create_file)
  48 #define remove_sysfs_device_files(dev)  \
  49         setup_sys_fs_device_files(dev, (acpi_device_sysfs_files *)&sysfs_remove_file)
  50
  51 #define to_acpi_device(n) container_of(n, struct acpi_device, kobj)
  52 #define to_handle_attr(n) container_of(n, struct acpi_device_attribute, attr);
  53
  54 static ssize_t acpi_device_attr_show(struct kobject *kobj,
  55                                      struct attribute *attr, char *buf)
  56 {
  57         struct acpi_device *device = to_acpi_device(kobj);
  58         struct acpi_device_attribute *attribute = to_handle_attr(attr);
  59         return attribute->show ? attribute->show(device, buf) : -EIO;
  60 }
  61 static ssize_t acpi_device_attr_store(struct kobject *kobj,
  62                                       struct attribute *attr, const char *buf,
  63                                       size_t len)
  64 {
  65         struct acpi_device *device = to_acpi_device(kobj);
  66         struct acpi_device_attribute *attribute = to_handle_attr(attr);
  67         return attribute->store ? attribute->store(device, buf, len) : -EIO;
  68 }
  69
  70 static struct sysfs_ops acpi_device_sysfs_ops = {
  71         .show = acpi_device_attr_show,
  72         .store = acpi_device_attr_store,
  73 };
  74
  75 static struct kobj_type ktype_acpi_ns = {
  76         .sysfs_ops = &acpi_device_sysfs_ops,
  77         .release = acpi_device_release,
  78 };
  79
  80 static int namespace_uevent(struct kset *kset, struct kobject *kobj,
  81                              char **envp, int num_envp, char *buffer,
  82                              int buffer_size)
  83 {
  84         struct acpi_device *dev = to_acpi_device(kobj);
  85         int i = 0;
  86         int len = 0;
  87
  88         if (!dev->driver)
  89                 return 0;
  90
  91         if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
  92                            "PHYSDEVDRIVER=%s", dev->driver->name))
  93                 return -ENOMEM;
  94
  95         envp[i] = NULL;
  96
  97         return 0;
  98 }
  99
 100 static struct kset_uevent_ops namespace_uevent_ops = {
 101         .uevent = &namespace_uevent,
 102 };
 103
 104 static struct kset acpi_namespace_kset = {
 105         .kobj = {
 106                  .name = "namespace",
 107                  },
 108         .subsys = &acpi_subsys,
 109         .ktype = &ktype_acpi_ns,
 110         .uevent_ops = &namespace_uevent_ops,
 111 };
 112
 113 static void acpi_device_register(struct acpi_device *device,
 114                                  struct acpi_device *parent)
 115 {
 116         /*
 117          * Linkage
 118          * -------
 119          * Link this device to its parent and siblings.
 120          */
 121         INIT_LIST_HEAD(&device->children);
 122         INIT_LIST_HEAD(&device->node);
 123         INIT_LIST_HEAD(&device->g_list);
 124         INIT_LIST_HEAD(&device->wakeup_list);
 125
 126         spin_lock(&acpi_device_lock);
 127         if (device->parent) {
 128                 list_add_tail(&device->node, &device->parent->children);
 129                 list_add_tail(&device->g_list, &device->parent->g_list);
 130         } else
 131                 list_add_tail(&device->g_list, &acpi_device_list);
 132         if (device->wakeup.flags.valid)
 133                 list_add_tail(&device->wakeup_list, &acpi_wakeup_device_list);
 134         spin_unlock(&acpi_device_lock);
 135
 136         strlcpy(device->kobj.name, device->pnp.bus_id, KOBJ_NAME_LEN);
 137         if (parent)
 138                 device->kobj.parent = &parent->kobj;
 139         device->kobj.ktype = &ktype_acpi_ns;
 140         device->kobj.kset = &acpi_namespace_kset;
 141         kobject_register(&device->kobj);
 142         create_sysfs_device_files(device);
 143 }
 144
 145 static int acpi_device_unregister(struct acpi_device *device, int type)
 146 {
 147         spin_lock(&acpi_device_lock);
 148         if (device->parent) {
 149                 list_del(&device->node);
 150                 list_del(&device->g_list);
 151         } else
 152                 list_del(&device->g_list);
 153
 154         list_del(&device->wakeup_list);
 155
 156         spin_unlock(&acpi_device_lock);
 157
 158         acpi_detach_data(device->handle, acpi_bus_data_handler);
 159         remove_sysfs_device_files(device);
 160         kobject_unregister(&device->kobj);
 161         return 0;
 162 }
 163
 164 void acpi_bus_data_handler(acpi_handle handle, u32 function, void *context)
 165 {
 166         ACPI_FUNCTION_TRACE("acpi_bus_data_handler");
 167
 168         /* TBD */
 169
 170         return_VOID;
 171 }
 172
 173 static int acpi_bus_get_power_flags(struct acpi_device *device)
 174 {
 175         acpi_status status = 0;
 176         acpi_handle handle = NULL;
 177         u32 i = 0;
 178
 179         ACPI_FUNCTION_TRACE("acpi_bus_get_power_flags");
 180
 181         /*
 182          * Power Management Flags
 183          */
 184         status = acpi_get_handle(device->handle, "_PSC", &handle);
 185         if (ACPI_SUCCESS(status))
 186                 device->power.flags.explicit_get = 1;
 187         status = acpi_get_handle(device->handle, "_IRC", &handle);
 188         if (ACPI_SUCCESS(status))
 189                 device->power.flags.inrush_current = 1;
 190
 191         /*
 192          * Enumerate supported power management states
 193          */
 194         for (i = ACPI_STATE_D0; i <= ACPI_STATE_D3; i++) {
 195                 struct acpi_device_power_state *ps = &device->power.states[i];
 196                 char object_name[5] = { '_', 'P', 'R', '0' + i, '\0' };
 197
 198                 /* Evaluate "_PRx" to se if power resources are referenced */
 199                 acpi_evaluate_reference(device->handle, object_name, NULL,
 200                                         &ps->resources);
 201                 if (ps->resources.count) {
 202                         device->power.flags.power_resources = 1;
 203                         ps->flags.valid = 1;
 204                 }
 205
 206                 /* Evaluate "_PSx" to see if we can do explicit sets */
 207                 object_name[2] = 'S';
 208                 status = acpi_get_handle(device->handle, object_name, &handle);
 209                 if (ACPI_SUCCESS(status)) {
 210                         ps->flags.explicit_set = 1;
 211                         ps->flags.valid = 1;
 212                 }
 213
 214                 /* State is valid if we have some power control */
 215                 if (ps->resources.count || ps->flags.explicit_set)
 216                         ps->flags.valid = 1;
 217
 218                 ps->power = -1; /* Unknown - driver assigned */
 219                 ps->latency = -1;       /* Unknown - driver assigned */
 220         }
 221
 222         /* Set defaults for D0 and D3 states (always valid) */
 223         device->power.states[ACPI_STATE_D0].flags.valid = 1;
 224         device->power.states[ACPI_STATE_D0].power = 100;
 225         device->power.states[ACPI_STATE_D3].flags.valid = 1;
 226         device->power.states[ACPI_STATE_D3].power = 0;
 227
 228         /* TBD: System wake support and resource requirements. */
 229
 230         device->power.state = ACPI_STATE_UNKNOWN;
 231
 232         return_VALUE(0);
 233 }
 234
 235 int acpi_match_ids(struct acpi_device *device, char *ids)
 236 {
 237         int error = 0;
 238         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 239
 240         if (device->flags.hardware_id)
 241                 if (strstr(ids, device->pnp.hardware_id))
 242                         goto Done;
 243
 244         if (device->flags.compatible_ids) {
 245                 struct acpi_compatible_id_list *cid_list = device->pnp.cid_list;
 246                 int i;
 247
 248                 /* compare multiple _CID entries against driver ids */
 249                 for (i = 0; i < cid_list->count; i++) {
 250                         if (strstr(ids, cid_list->id[i].value))
 251                                 goto Done;
 252                 }
 253         }
 254         error = -ENOENT;
 255
 256       Done:
 257         if (buffer.pointer)
 258                 acpi_os_free(buffer.pointer);
 259         return error;
 260 }
 261
 262 static acpi_status
 263 acpi_bus_extract_wakeup_device_power_package(struct acpi_device *device,
 264                                              union acpi_object *package)
 265 {
 266         int i = 0;
 267         union acpi_object *element = NULL;
 268
 269         if (!device || !package || (package->package.count < 2))
 270                 return AE_BAD_PARAMETER;
 271
 272         element = &(package->package.elements[0]);
 273         if (!element)
 274                 return AE_BAD_PARAMETER;
 275         if (element->type == ACPI_TYPE_PACKAGE) {
 276                 if ((element->package.count < 2) ||
 277                     (element->package.elements[0].type !=
 278                      ACPI_TYPE_LOCAL_REFERENCE)
 279                     || (element->package.elements[1].type != ACPI_TYPE_INTEGER))
 280                         return AE_BAD_DATA;
 281                 device->wakeup.gpe_device =
 282                     element->package.elements[0].reference.handle;
 283                 device->wakeup.gpe_number =
 284                     (u32) element->package.elements[1].integer.value;
 285         } else if (element->type == ACPI_TYPE_INTEGER) {
 286                 device->wakeup.gpe_number = element->integer.value;
 287         } else
 288                 return AE_BAD_DATA;
 289
 290         element = &(package->package.elements[1]);
 291         if (element->type != ACPI_TYPE_INTEGER) {
 292                 return AE_BAD_DATA;
 293         }
 294         device->wakeup.sleep_state = element->integer.value;
 295
 296         if ((package->package.count - 2) > ACPI_MAX_HANDLES) {
 297                 return AE_NO_MEMORY;
 298         }
 299         device->wakeup.resources.count = package->package.count - 2;
 300         for (i = 0; i < device->wakeup.resources.count; i++) {
 301                 element = &(package->package.elements[i + 2]);
 302                 if (element->type != ACPI_TYPE_ANY) {
 303                         return AE_BAD_DATA;
 304                 }
 305
 306                 device->wakeup.resources.handles[i] = element->reference.handle;
 307         }
 308
 309         return AE_OK;
 310 }
 311
 312 static int acpi_bus_get_wakeup_device_flags(struct acpi_device *device)
 313 {
 314         acpi_status status = 0;
 315         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 316         union acpi_object *package = NULL;
 317
 318         ACPI_FUNCTION_TRACE("acpi_bus_get_wakeup_flags");
 319
 320         /* _PRW */
 321         status = acpi_evaluate_object(device->handle, "_PRW", NULL, &buffer);
 322         if (ACPI_FAILURE(status)) {
 323                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _PRW\n"));
 324                 goto end;
 325         }
 326
 327         package = (union acpi_object *)buffer.pointer;
 328         status = acpi_bus_extract_wakeup_device_power_package(device, package);
 329         if (ACPI_FAILURE(status)) {
 330                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 331                                   "Error extracting _PRW package\n"));
 332                 goto end;
 333         }
 334
 335         acpi_os_free(buffer.pointer);
 336
 337         device->wakeup.flags.valid = 1;
 338         /* Power button, Lid switch always enable wakeup */
 339         if (!acpi_match_ids(device, "PNP0C0D,PNP0C0C,PNP0C0E"))
 340                 device->wakeup.flags.run_wake = 1;
 341
 342       end:
 343         if (ACPI_FAILURE(status))
 344                 device->flags.wake_capable = 0;
 345         return_VALUE(0);
 346 }
 347
 348 /* --------------------------------------------------------------------------
 349                 ACPI sysfs device file support
 350    -------------------------------------------------------------------------- */
 351 static ssize_t acpi_eject_store(struct acpi_device *device,
 352                                 const char *buf, size_t count);
 353
 354 #define ACPI_DEVICE_ATTR(_name,_mode,_show,_store) \
 355 static struct acpi_device_attribute acpi_device_attr_##_name = \
 356                 __ATTR(_name, _mode, _show, _store)
 357
 358 ACPI_DEVICE_ATTR(eject, 0200, NULL, acpi_eject_store);
 359
 360 /**
 361  * setup_sys_fs_device_files - sets up the device files under device namespace
 362  * @dev:        acpi_device object
 363  * @func:       function pointer to create or destroy the device file
 364  */
 365 static void
 366 setup_sys_fs_device_files(struct acpi_device *dev,
 367                           acpi_device_sysfs_files * func)
 368 {
 369         acpi_status status;
 370         acpi_handle temp = NULL;
 371
 372         /*
 373          * If device has _EJ0, 'eject' file is created that is used to trigger
 374          * hot-removal function from userland.
 375          */
 376         status = acpi_get_handle(dev->handle, "_EJ0", &temp);
 377         if (ACPI_SUCCESS(status))
 378                 (*(func)) (&dev->kobj, &acpi_device_attr_eject.attr);
 379 }
 380
 381 static int acpi_eject_operation(acpi_handle handle, int lockable)
 382 {
 383         struct acpi_object_list arg_list;
 384         union acpi_object arg;
 385         acpi_status status = AE_OK;
 386
 387         /*
 388          * TBD: evaluate _PS3?
 389          */
 390
 391         if (lockable) {
 392                 arg_list.count = 1;
 393                 arg_list.pointer = &arg;
 394                 arg.type = ACPI_TYPE_INTEGER;
 395                 arg.integer.value = 0;
 396                 acpi_evaluate_object(handle, "_LCK", &arg_list, NULL);
 397         }
 398
 399         arg_list.count = 1;
 400         arg_list.pointer = &arg;
 401         arg.type = ACPI_TYPE_INTEGER;
 402         arg.integer.value = 1;
 403
 404         /*
 405          * TBD: _EJD support.
 406          */
 407
 408         status = acpi_evaluate_object(handle, "_EJ0", &arg_list, NULL);
 409         if (ACPI_FAILURE(status)) {
 410                 return (-ENODEV);
 411         }
 412
 413         return (0);
 414 }
 415
 416 static ssize_t
 417 acpi_eject_store(struct acpi_device *device, const char *buf, size_t count)
 418 {
 419         int result;
 420         int ret = count;
 421         int islockable;
 422         acpi_status status;
 423         acpi_handle handle;
 424         acpi_object_type type = 0;
 425
 426         if ((!count) || (buf[0] != '1')) {
 427                 return -EINVAL;
 428         }
 429 #ifndef FORCE_EJECT
 430         if (device->driver == NULL) {
 431                 ret = -ENODEV;
 432                 goto err;
 433         }
 434 #endif
 435         status = acpi_get_type(device->handle, &type);
 436         if (ACPI_FAILURE(status) || (!device->flags.ejectable)) {
 437                 ret = -ENODEV;
 438                 goto err;
 439         }
 440
 441         islockable = device->flags.lockable;
 442         handle = device->handle;
 443
 444         if (type == ACPI_TYPE_PROCESSOR)
 445                 result = acpi_bus_trim(device, 0);
 446         else
 447                 result = acpi_bus_trim(device, 1);
 448
 449         if (!result)
 450                 result = acpi_eject_operation(handle, islockable);
 451
 452         if (result) {
 453                 ret = -EBUSY;
 454         }
 455       err:
 456         return ret;
 457 }
 458
 459 /* --------------------------------------------------------------------------
 460                               Performance Management
 461    -------------------------------------------------------------------------- */
 462
 463 static int acpi_bus_get_perf_flags(struct acpi_device *device)
 464 {
 465         device->performance.state = ACPI_STATE_UNKNOWN;
 466         return 0;
 467 }
 468
 469 /* --------------------------------------------------------------------------
 470                                  Driver Management
 471    -------------------------------------------------------------------------- */
 472
 473 static LIST_HEAD(acpi_bus_drivers);
 474 static DECLARE_MUTEX(acpi_bus_drivers_lock);
 475
 476 /**
 477  * acpi_bus_match - match device IDs to driver's supported IDs
 478  * @device: the device that we are trying to match to a driver
 479  * @driver: driver whose device id table is being checked
 480  *
 481  * Checks the device's hardware (_HID) or compatible (_CID) ids to see if it
 482  * matches the specified driver's criteria.
 483  */
 484 static int
 485 acpi_bus_match(struct acpi_device *device, struct acpi_driver *driver)
 486 {
 487         if (driver && driver->ops.match)
 488                 return driver->ops.match(device, driver);
 489         return acpi_match_ids(device, driver->ids);
 490 }
 491
 492 /**
 493  * acpi_bus_driver_init - add a device to a driver
 494  * @device: the device to add and initialize
 495  * @driver: driver for the device
 496  *
 497  * Used to initialize a device via its device driver.  Called whenever a
 498  * driver is bound to a device.  Invokes the driver's add() and start() ops.
 499  */
 500 static int
 501 acpi_bus_driver_init(struct acpi_device *device, struct acpi_driver *driver)
 502 {
 503         int result = 0;
 504
 505         ACPI_FUNCTION_TRACE("acpi_bus_driver_init");
 506
 507         if (!device || !driver)
 508                 return_VALUE(-EINVAL);
 509
 510         if (!driver->ops.add)
 511                 return_VALUE(-ENOSYS);
 512
 513         result = driver->ops.add(device);
 514         if (result) {
 515                 device->driver = NULL;
 516                 acpi_driver_data(device) = NULL;
 517                 return_VALUE(result);
 518         }
 519
 520         device->driver = driver;
 521
 522         /*
 523          * TBD - Configuration Management: Assign resources to device based
 524          * upon possible configuration and currently allocated resources.
 525          */
 526
 527         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 528                           "Driver successfully bound to device\n"));
 529         return_VALUE(0);
 530 }
 531
 532 static int acpi_start_single_object(struct acpi_device *device)
 533 {
 534         int result = 0;
 535         struct acpi_driver *driver;
 536
 537         ACPI_FUNCTION_TRACE("acpi_start_single_object");
 538
 539         if (!(driver = device->driver))
 540                 return_VALUE(0);
 541
 542         if (driver->ops.start) {
 543                 result = driver->ops.start(device);
 544                 if (result && driver->ops.remove)
 545                         driver->ops.remove(device, ACPI_BUS_REMOVAL_NORMAL);
 546         }
 547
 548         return_VALUE(result);
 549 }
 550
 551 static int acpi_driver_attach(struct acpi_driver *drv)
 552 {
 553         struct list_head *node, *next;
 554         int count = 0;
 555
 556         ACPI_FUNCTION_TRACE("acpi_driver_attach");
 557
 558         spin_lock(&acpi_device_lock);
 559         list_for_each_safe(node, next, &acpi_device_list) {
 560                 struct acpi_device *dev =
 561                     container_of(node, struct acpi_device, g_list);
 562
 563                 if (dev->driver || !dev->status.present)
 564                         continue;
 565                 spin_unlock(&acpi_device_lock);
 566
 567                 if (!acpi_bus_match(dev, drv)) {
 568                         if (!acpi_bus_driver_init(dev, drv)) {
 569                                 acpi_start_single_object(dev);
 570                                 atomic_inc(&drv->references);
 571                                 count++;
 572                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 573                                                   "Found driver [%s] for device [%s]\n",
 574                                                   drv->name, dev->pnp.bus_id));
 575                         }
 576                 }
 577                 spin_lock(&acpi_device_lock);
 578         }
 579         spin_unlock(&acpi_device_lock);
 580         return_VALUE(count);
 581 }
 582
 583 static int acpi_driver_detach(struct acpi_driver *drv)
 584 {
 585         struct list_head *node, *next;
 586
 587         ACPI_FUNCTION_TRACE("acpi_driver_detach");
 588
 589         spin_lock(&acpi_device_lock);
 590         list_for_each_safe(node, next, &acpi_device_list) {
 591                 struct acpi_device *dev =
 592                     container_of(node, struct acpi_device, g_list);
 593
 594                 if (dev->driver == drv) {
 595                         spin_unlock(&acpi_device_lock);
 596                         if (drv->ops.remove)
 597                                 drv->ops.remove(dev, ACPI_BUS_REMOVAL_NORMAL);
 598                         spin_lock(&acpi_device_lock);
 599                         dev->driver = NULL;
 600                         dev->driver_data = NULL;
 601                         atomic_dec(&drv->references);
 602                 }
 603         }
 604         spin_unlock(&acpi_device_lock);
 605         return_VALUE(0);
 606 }
 607
 608 /**
 609  * acpi_bus_register_driver - register a driver with the ACPI bus
 610  * @driver: driver being registered
 611  *
 612  * Registers a driver with the ACPI bus.  Searches the namespace for all
 613  * devices that match the driver's criteria and binds.  Returns the
 614  * number of devices that were claimed by the driver, or a negative
 615  * error status for failure.
 616  */
 617 int acpi_bus_register_driver(struct acpi_driver *driver)
 618 {
 619         int count;
 620
 621         ACPI_FUNCTION_TRACE("acpi_bus_register_driver");
 622
 623         if (acpi_disabled)
 624                 return_VALUE(-ENODEV);
 625
 626         if (!driver)
 627                 return_VALUE(-EINVAL);
 628
 629         spin_lock(&acpi_device_lock);
 630         list_add_tail(&driver->node, &acpi_bus_drivers);
 631         spin_unlock(&acpi_device_lock);
 632         count = acpi_driver_attach(driver);
 633
 634         return_VALUE(count);
 635 }
 636
 637 EXPORT_SYMBOL(acpi_bus_register_driver);
 638
 639 /**
 640  * acpi_bus_unregister_driver - unregisters a driver with the APIC bus
 641  * @driver: driver to unregister
 642  *
 643  * Unregisters a driver with the ACPI bus.  Searches the namespace for all
 644  * devices that match the driver's criteria and unbinds.
 645  */
 646 int acpi_bus_unregister_driver(struct acpi_driver *driver)
 647 {
 648         int error = 0;
 649
 650         ACPI_FUNCTION_TRACE("acpi_bus_unregister_driver");
 651
 652         if (driver) {
 653                 acpi_driver_detach(driver);
 654
 655                 if (!atomic_read(&driver->references)) {
 656                         spin_lock(&acpi_device_lock);
 657                         list_del_init(&driver->node);
 658                         spin_unlock(&acpi_device_lock);
 659                 }
 660         } else
 661                 error = -EINVAL;
 662         return_VALUE(error);
 663 }
 664
 665 EXPORT_SYMBOL(acpi_bus_unregister_driver);
 666
 667 /**
 668  * acpi_bus_find_driver - check if there is a driver installed for the device
 669  * @device: device that we are trying to find a supporting driver for
 670  *
 671  * Parses the list of registered drivers looking for a driver applicable for
 672  * the specified device.
 673  */
 674 static int acpi_bus_find_driver(struct acpi_device *device)
 675 {
 676         int result = 0;
 677         struct list_head *node, *next;
 678
 679         ACPI_FUNCTION_TRACE("acpi_bus_find_driver");
 680
 681         spin_lock(&acpi_device_lock);
 682         list_for_each_safe(node, next, &acpi_bus_drivers) {
 683                 struct acpi_driver *driver =
 684                     container_of(node, struct acpi_driver, node);
 685
 686                 atomic_inc(&driver->references);
 687                 spin_unlock(&acpi_device_lock);
 688                 if (!acpi_bus_match(device, driver)) {
 689                         result = acpi_bus_driver_init(device, driver);
 690                         if (!result)
 691                                 goto Done;
 692                 }
 693                 atomic_dec(&driver->references);
 694                 spin_lock(&acpi_device_lock);
 695         }
 696         spin_unlock(&acpi_device_lock);
 697
 698       Done:
 699         return_VALUE(result);
 700 }
 701
 702 /* --------------------------------------------------------------------------
 703                                  Device Enumeration
 704    -------------------------------------------------------------------------- */
 705
 706 static int acpi_bus_get_flags(struct acpi_device *device)
 707 {
 708         acpi_status status = AE_OK;
 709         acpi_handle temp = NULL;
 710
 711         ACPI_FUNCTION_TRACE("acpi_bus_get_flags");
 712
 713         /* Presence of _STA indicates 'dynamic_status' */
 714         status = acpi_get_handle(device->handle, "_STA", &temp);
 715         if (ACPI_SUCCESS(status))
 716                 device->flags.dynamic_status = 1;
 717
 718         /* Presence of _CID indicates 'compatible_ids' */
 719         status = acpi_get_handle(device->handle, "_CID", &temp);
 720         if (ACPI_SUCCESS(status))
 721                 device->flags.compatible_ids = 1;
 722
 723         /* Presence of _RMV indicates 'removable' */
 724         status = acpi_get_handle(device->handle, "_RMV", &temp);
 725         if (ACPI_SUCCESS(status))
 726                 device->flags.removable = 1;
 727
 728         /* Presence of _EJD|_EJ0 indicates 'ejectable' */
 729         status = acpi_get_handle(device->handle, "_EJD", &temp);
 730         if (ACPI_SUCCESS(status))
 731                 device->flags.ejectable = 1;
 732         else {
 733                 status = acpi_get_handle(device->handle, "_EJ0", &temp);
 734                 if (ACPI_SUCCESS(status))
 735                         device->flags.ejectable = 1;
 736         }
 737
 738         /* Presence of _LCK indicates 'lockable' */
 739         status = acpi_get_handle(device->handle, "_LCK", &temp);
 740         if (ACPI_SUCCESS(status))
 741                 device->flags.lockable = 1;
 742
 743         /* Presence of _PS0|_PR0 indicates 'power manageable' */
 744         status = acpi_get_handle(device->handle, "_PS0", &temp);
 745         if (ACPI_FAILURE(status))
 746                 status = acpi_get_handle(device->handle, "_PR0", &temp);
 747         if (ACPI_SUCCESS(status))
 748                 device->flags.power_manageable = 1;
 749
 750         /* Presence of _PRW indicates wake capable */
 751         status = acpi_get_handle(device->handle, "_PRW", &temp);
 752         if (ACPI_SUCCESS(status))
 753                 device->flags.wake_capable = 1;
 754
 755         /* TBD: Peformance management */
 756
 757         return_VALUE(0);
 758 }
 759
 760 static void acpi_device_get_busid(struct acpi_device *device,
 761                                   acpi_handle handle, int type)
 762 {
 763         char bus_id[5] = { '?', 0 };
 764         struct acpi_buffer buffer = { sizeof(bus_id), bus_id };
 765         int i = 0;
 766
 767         /*
 768          * Bus ID
 769          * ------
 770          * The device's Bus ID is simply the object name.
 771          * TBD: Shouldn't this value be unique (within the ACPI namespace)?
 772          */
 773         switch (type) {
 774         case ACPI_BUS_TYPE_SYSTEM:
 775                 strcpy(device->pnp.bus_id, "ACPI");
 776                 break;
 777         case ACPI_BUS_TYPE_POWER_BUTTON:
 778                 strcpy(device->pnp.bus_id, "PWRF");
 779                 break;
 780         case ACPI_BUS_TYPE_SLEEP_BUTTON:
 781                 strcpy(device->pnp.bus_id, "SLPF");
 782                 break;
 783         default:
 784                 acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
 785                 /* Clean up trailing underscores (if any) */
 786                 for (i = 3; i > 1; i--) {
 787                         if (bus_id[i] == '_')
 788                                 bus_id[i] = '\0';
 789                         else
 790                                 break;
 791                 }
 792                 strcpy(device->pnp.bus_id, bus_id);
 793                 break;
 794         }
 795 }
 796
 797 static void acpi_device_set_id(struct acpi_device *device,
 798                                struct acpi_device *parent, acpi_handle handle,
 799                                int type)
 800 {
 801         struct acpi_device_info *info;
 802         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 803         char *hid = NULL;
 804         char *uid = NULL;
 805         struct acpi_compatible_id_list *cid_list = NULL;
 806         acpi_status status;
 807
 808         switch (type) {
 809         case ACPI_BUS_TYPE_DEVICE:
 810                 status = acpi_get_object_info(handle, &buffer);
 811                 if (ACPI_FAILURE(status)) {
 812                         printk("%s: Error reading device info\n", __FUNCTION__);
 813                         return;
 814                 }
 815
 816                 info = buffer.pointer;
 817                 if (info->valid & ACPI_VALID_HID)
 818                         hid = info->hardware_id.value;
 819                 if (info->valid & ACPI_VALID_UID)
 820                         uid = info->unique_id.value;
 821                 if (info->valid & ACPI_VALID_CID)
 822                         cid_list = &info->compatibility_id;
 823                 if (info->valid & ACPI_VALID_ADR) {
 824                         device->pnp.bus_address = info->address;
 825                         device->flags.bus_address = 1;
 826                 }
 827                 break;
 828         case ACPI_BUS_TYPE_POWER:
 829                 hid = ACPI_POWER_HID;
 830                 break;
 831         case ACPI_BUS_TYPE_PROCESSOR:
 832                 hid = ACPI_PROCESSOR_HID;
 833                 break;
 834         case ACPI_BUS_TYPE_SYSTEM:
 835                 hid = ACPI_SYSTEM_HID;
 836                 break;
 837         case ACPI_BUS_TYPE_THERMAL:
 838                 hid = ACPI_THERMAL_HID;
 839                 break;
 840         case ACPI_BUS_TYPE_POWER_BUTTON:
 841                 hid = ACPI_BUTTON_HID_POWERF;
 842                 break;
 843         case ACPI_BUS_TYPE_SLEEP_BUTTON:
 844                 hid = ACPI_BUTTON_HID_SLEEPF;
 845                 break;
 846         }
 847
 848         /*
 849          * \_SB
 850          * ----
 851          * Fix for the system root bus device -- the only root-level device.
 852          */
 853         if (((acpi_handle)parent == ACPI_ROOT_OBJECT) && (type == ACPI_BUS_TYPE_DEVICE)) {
 854                 hid = ACPI_BUS_HID;
 855                 strcpy(device->pnp.device_name, ACPI_BUS_DEVICE_NAME);
 856                 strcpy(device->pnp.device_class, ACPI_BUS_CLASS);
 857         }
 858
 859         if (hid) {
 860                 strcpy(device->pnp.hardware_id, hid);
 861                 device->flags.hardware_id = 1;
 862         }
 863         if (uid) {
 864                 strcpy(device->pnp.unique_id, uid);
 865                 device->flags.unique_id = 1;
 866         }
 867         if (cid_list) {
 868                 device->pnp.cid_list = kmalloc(cid_list->size, GFP_KERNEL);
 869                 if (device->pnp.cid_list)
 870                         memcpy(device->pnp.cid_list, cid_list, cid_list->size);
 871                 else
 872                         printk(KERN_ERR "Memory allocation error\n");
 873         }
 874
 875         acpi_os_free(buffer.pointer);
 876 }
 877
 878 static int acpi_device_set_context(struct acpi_device *device, int type)
 879 {
 880         acpi_status status = AE_OK;
 881         int result = 0;
 882         /*
 883          * Context
 884          * -------
 885          * Attach this 'struct acpi_device' to the ACPI object.  This makes
 886          * resolutions from handle->device very efficient.  Note that we need
 887          * to be careful with fixed-feature devices as they all attach to the
 888          * root object.
 889          */
 890         if (type != ACPI_BUS_TYPE_POWER_BUTTON &&
 891             type != ACPI_BUS_TYPE_SLEEP_BUTTON) {
 892                 status = acpi_attach_data(device->handle,
 893                                           acpi_bus_data_handler, device);
 894
 895                 if (ACPI_FAILURE(status)) {
 896                         printk("Error attaching device data\n");
 897                         result = -ENODEV;
 898                 }
 899         }
 900         return result;
 901 }
 902
 903 static void acpi_device_get_debug_info(struct acpi_device *device,
 904                                        acpi_handle handle, int type)
 905 {
 906 #ifdef CONFIG_ACPI_DEBUG_OUTPUT
 907         char *type_string = NULL;
 908         char name[80] = { '?', '\0' };
 909         struct acpi_buffer buffer = { sizeof(name), name };
 910
 911         switch (type) {
 912         case ACPI_BUS_TYPE_DEVICE:
 913                 type_string = "Device";
 914                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 915                 break;
 916         case ACPI_BUS_TYPE_POWER:
 917                 type_string = "Power Resource";
 918                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 919                 break;
 920         case ACPI_BUS_TYPE_PROCESSOR:
 921                 type_string = "Processor";
 922                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 923                 break;
 924         case ACPI_BUS_TYPE_SYSTEM:
 925                 type_string = "System";
 926                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 927                 break;
 928         case ACPI_BUS_TYPE_THERMAL:
 929                 type_string = "Thermal Zone";
 930                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 931                 break;
 932         case ACPI_BUS_TYPE_POWER_BUTTON:
 933                 type_string = "Power Button";
 934                 sprintf(name, "PWRB");
 935                 break;
 936         case ACPI_BUS_TYPE_SLEEP_BUTTON:
 937                 type_string = "Sleep Button";
 938                 sprintf(name, "SLPB");
 939                 break;
 940         }
 941
 942         printk(KERN_DEBUG "Found %s %s [%p]\n", type_string, name, handle);
 943 #endif                          /*CONFIG_ACPI_DEBUG_OUTPUT */
 944 }
 945
 946 static int acpi_bus_remove(struct acpi_device *dev, int rmdevice)
 947 {
 948         int result = 0;
 949         struct acpi_driver *driver;
 950
 951         ACPI_FUNCTION_TRACE("acpi_bus_remove");
 952
 953         if (!dev)
 954                 return_VALUE(-EINVAL);
 955
 956         driver = dev->driver;
 957
 958         if ((driver) && (driver->ops.remove)) {
 959
 960                 if (driver->ops.stop) {
 961                         result = driver->ops.stop(dev, ACPI_BUS_REMOVAL_EJECT);
 962                         if (result)
 963                                 return_VALUE(result);
 964                 }
 965
 966                 result = dev->driver->ops.remove(dev, ACPI_BUS_REMOVAL_EJECT);
 967                 if (result) {
 968                         return_VALUE(result);
 969                 }
 970
 971                 atomic_dec(&dev->driver->references);
 972                 dev->driver = NULL;
 973                 acpi_driver_data(dev) = NULL;
 974         }
 975
 976         if (!rmdevice)
 977                 return_VALUE(0);
 978
 979         if (dev->flags.bus_address) {
 980                 if ((dev->parent) && (dev->parent->ops.unbind))
 981                         dev->parent->ops.unbind(dev);
 982         }
 983
 984         acpi_device_unregister(dev, ACPI_BUS_REMOVAL_EJECT);
 985
 986         return_VALUE(0);
 987 }
 988
 989 static int
 990 acpi_add_single_object(struct acpi_device **child,
 991                        struct acpi_device *parent, acpi_handle handle, int type)
 992 {
 993         int result = 0;
 994         struct acpi_device *device = NULL;
 995
 996         ACPI_FUNCTION_TRACE("acpi_add_single_object");
 997
 998         if (!child)
 999                 return_VALUE(-EINVAL);
1000
1001         device = kmalloc(sizeof(struct acpi_device), GFP_KERNEL);
1002         if (!device) {
1003                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Memory allocation error\n"));
1004                 return_VALUE(-ENOMEM);
1005         }
1006         memset(device, 0, sizeof(struct acpi_device));
1007
1008         device->handle = handle;
1009         device->parent = parent;
1010
1011         acpi_device_get_busid(device, handle, type);
1012
1013         /*
1014          * Flags
1015          * -----
1016          * Get prior to calling acpi_bus_get_status() so we know whether
1017          * or not _STA is present.  Note that we only look for object
1018          * handles -- cannot evaluate objects until we know the device is
1019          * present and properly initialized.
1020          */
1021         result = acpi_bus_get_flags(device);
1022         if (result)
1023                 goto end;
1024
1025         /*
1026          * Status
1027          * ------
1028          * See if the device is present.  We always assume that non-Device
1029          * and non-Processor objects (e.g. thermal zones, power resources,
1030          * etc.) are present, functioning, etc. (at least when parent object
1031          * is present).  Note that _STA has a different meaning for some
1032          * objects (e.g. power resources) so we need to be careful how we use
1033          * it.
1034          */
1035         switch (type) {
1036         case ACPI_BUS_TYPE_PROCESSOR:
1037         case ACPI_BUS_TYPE_DEVICE:
1038                 result = acpi_bus_get_status(device);
1039                 if (ACPI_FAILURE(result) || !device->status.present) {
1040                         result = -ENOENT;
1041                         goto end;
1042                 }
1043                 break;
1044         default:
1045                 STRUCT_TO_INT(device->status) = 0x0F;
1046                 break;
1047         }
1048
1049         /*
1050          * Initialize Device
1051          * -----------------
1052          * TBD: Synch with Core's enumeration/initialization process.
1053          */
1054
1055         /*
1056          * Hardware ID, Unique ID, & Bus Address
1057          * -------------------------------------
1058          */
1059         acpi_device_set_id(device, parent, handle, type);
1060
1061         /*
1062          * Power Management
1063          * ----------------
1064          */
1065         if (device->flags.power_manageable) {
1066                 result = acpi_bus_get_power_flags(device);
1067                 if (result)
1068                         goto end;
1069         }
1070
1071         /*
1072          * Wakeup device management
1073          *-----------------------
1074          */
1075         if (device->flags.wake_capable) {
1076                 result = acpi_bus_get_wakeup_device_flags(device);
1077                 if (result)
1078                         goto end;
1079         }
1080
1081         /*
1082          * Performance Management
1083          * ----------------------
1084          */
1085         if (device->flags.performance_manageable) {
1086                 result = acpi_bus_get_perf_flags(device);
1087                 if (result)
1088                         goto end;
1089         }
1090
1091         if ((result = acpi_device_set_context(device, type)))
1092                 goto end;
1093
1094         acpi_device_get_debug_info(device, handle, type);
1095
1096         acpi_device_register(device, parent);
1097
1098         /*
1099          * Bind _ADR-Based Devices
1100          * -----------------------
1101          * If there's a a bus address (_ADR) then we utilize the parent's
1102          * 'bind' function (if exists) to bind the ACPI- and natively-
1103          * enumerated device representations.
1104          */
1105         if (device->flags.bus_address) {
1106                 if (device->parent && device->parent->ops.bind)
1107                         device->parent->ops.bind(device);
1108         }
1109
1110         /*
1111          * Locate & Attach Driver
1112          * ----------------------
1113          * If there's a hardware id (_HID) or compatible ids (_CID) we check
1114          * to see if there's a driver installed for this kind of device.  Note
1115          * that drivers can install before or after a device is enumerated.
1116          *
1117          * TBD: Assumes LDM provides driver hot-plug capability.
1118          */
1119         acpi_bus_find_driver(device);
1120
1121       end:
1122         if (!result)
1123                 *child = device;
1124         else {
1125                 kfree(device->pnp.cid_list);
1126                 kfree(device);
1127         }
1128
1129         return_VALUE(result);
1130 }
1131
1132 static int acpi_bus_scan(struct acpi_device *start, struct acpi_bus_ops *ops)
1133 {
1134         acpi_status status = AE_OK;
1135         struct acpi_device *parent = NULL;
1136         struct acpi_device *child = NULL;
1137         acpi_handle phandle = NULL;
1138         acpi_handle chandle = NULL;
1139         acpi_object_type type = 0;
1140         u32 level = 1;
1141
1142         ACPI_FUNCTION_TRACE("acpi_bus_scan");
1143
1144         if (!start)
1145                 return_VALUE(-EINVAL);
1146
1147         parent = start;
1148         phandle = start->handle;
1149
1150         /*
1151          * Parse through the ACPI namespace, identify all 'devices', and
1152          * create a new 'struct acpi_device' for each.
1153          */
1154         while ((level > 0) && parent) {
1155
1156                 status = acpi_get_next_object(ACPI_TYPE_ANY, phandle,
1157                                               chandle, &chandle);
1158
1159                 /*
1160                  * If this scope is exhausted then move our way back up.
1161                  */
1162                 if (ACPI_FAILURE(status)) {
1163                         level--;
1164                         chandle = phandle;
1165                         acpi_get_parent(phandle, &phandle);
1166                         if (parent->parent)
1167                                 parent = parent->parent;
1168                         continue;
1169                 }
1170
1171                 status = acpi_get_type(chandle, &type);
1172                 if (ACPI_FAILURE(status))
1173                         continue;
1174
1175                 /*
1176                  * If this is a scope object then parse it (depth-first).
1177                  */
1178                 if (type == ACPI_TYPE_LOCAL_SCOPE) {
1179                         level++;
1180                         phandle = chandle;
1181                         chandle = NULL;
1182                         continue;
1183                 }
1184
1185                 /*
1186                  * We're only interested in objects that we consider 'devices'.
1187                  */
1188                 switch (type) {
1189                 case ACPI_TYPE_DEVICE:
1190                         type = ACPI_BUS_TYPE_DEVICE;
1191                         break;
1192                 case ACPI_TYPE_PROCESSOR:
1193                         type = ACPI_BUS_TYPE_PROCESSOR;
1194                         break;
1195                 case ACPI_TYPE_THERMAL:
1196                         type = ACPI_BUS_TYPE_THERMAL;
1197                         break;
1198                 case ACPI_TYPE_POWER:
1199                         type = ACPI_BUS_TYPE_POWER;
1200                         break;
1201                 default:
1202                         continue;
1203                 }
1204
1205                 if (ops->acpi_op_add)
1206                         status = acpi_add_single_object(&child, parent,
1207                                                         chandle, type);
1208                 else
1209                         status = acpi_bus_get_device(chandle, &child);
1210
1211                 if (ACPI_FAILURE(status))
1212                         continue;
1213
1214                 if (ops->acpi_op_start) {
1215                         status = acpi_start_single_object(child);
1216                         if (ACPI_FAILURE(status))
1217                                 continue;
1218                 }
1219
1220                 /*
1221                  * If the device is present, enabled, and functioning then
1222                  * parse its scope (depth-first).  Note that we need to
1223                  * represent absent devices to facilitate PnP notifications
1224                  * -- but only the subtree head (not all of its children,
1225                  * which will be enumerated when the parent is inserted).
1226                  *
1227                  * TBD: Need notifications and other detection mechanisms
1228                  *      in place before we can fully implement this.
1229                  */
1230                 if (child->status.present) {
1231                         status = acpi_get_next_object(ACPI_TYPE_ANY, chandle,
1232                                                       NULL, NULL);
1233                         if (ACPI_SUCCESS(status)) {
1234                                 level++;
1235                                 phandle = chandle;
1236                                 chandle = NULL;
1237                                 parent = child;
1238                         }
1239                 }
1240         }
1241
1242         return_VALUE(0);
1243 }
1244
1245 int
1246 acpi_bus_add(struct acpi_device **child,
1247              struct acpi_device *parent, acpi_handle handle, int type)
1248 {
1249         int result;
1250         struct acpi_bus_ops ops;
1251
1252         ACPI_FUNCTION_TRACE("acpi_bus_add");
1253
1254         result = acpi_add_single_object(child, parent, handle, type);
1255         if (!result) {
1256                 memset(&ops, 0, sizeof(ops));
1257                 ops.acpi_op_add = 1;
1258                 result = acpi_bus_scan(*child, &ops);
1259         }
1260         return_VALUE(result);
1261 }
1262
1263 EXPORT_SYMBOL(acpi_bus_add);
1264
1265 int acpi_bus_start(struct acpi_device *device)
1266 {
1267         int result;
1268         struct acpi_bus_ops ops;
1269
1270         ACPI_FUNCTION_TRACE("acpi_bus_start");
1271
1272         if (!device)
1273                 return_VALUE(-EINVAL);
1274
1275         result = acpi_start_single_object(device);
1276         if (!result) {
1277                 memset(&ops, 0, sizeof(ops));
1278                 ops.acpi_op_start = 1;
1279                 result = acpi_bus_scan(device, &ops);
1280         }
1281         return_VALUE(result);
1282 }
1283
1284 EXPORT_SYMBOL(acpi_bus_start);
1285
1286 int acpi_bus_trim(struct acpi_device *start, int rmdevice)
1287 {
1288         acpi_status status;
1289         struct acpi_device *parent, *child;
1290         acpi_handle phandle, chandle;
1291         acpi_object_type type;
1292         u32 level = 1;
1293         int err = 0;
1294
1295         parent = start;
1296         phandle = start->handle;
1297         child = chandle = NULL;
1298
1299         while ((level > 0) && parent && (!err)) {
1300                 status = acpi_get_next_object(ACPI_TYPE_ANY, phandle,
1301                                               chandle, &chandle);
1302
1303                 /*
1304                  * If this scope is exhausted then move our way back up.
1305                  */
1306                 if (ACPI_FAILURE(status)) {
1307                         level--;
1308                         chandle = phandle;
1309                         acpi_get_parent(phandle, &phandle);
1310                         child = parent;
1311                         parent = parent->parent;
1312
1313                         if (level == 0)
1314                                 err = acpi_bus_remove(child, rmdevice);
1315                         else
1316                                 err = acpi_bus_remove(child, 1);
1317
1318                         continue;
1319                 }
1320
1321                 status = acpi_get_type(chandle, &type);
1322                 if (ACPI_FAILURE(status)) {
1323                         continue;
1324                 }
1325                 /*
1326                  * If there is a device corresponding to chandle then
1327                  * parse it (depth-first).
1328                  */
1329                 if (acpi_bus_get_device(chandle, &child) == 0) {
1330                         level++;
1331                         phandle = chandle;
1332                         chandle = NULL;
1333                         parent = child;
1334                 }
1335                 continue;
1336         }
1337         return err;
1338 }
1339 EXPORT_SYMBOL_GPL(acpi_bus_trim);
1340
1341
1342 static int acpi_bus_scan_fixed(struct acpi_device *root)
1343 {
1344         int result = 0;
1345         struct acpi_device *device = NULL;
1346
1347         ACPI_FUNCTION_TRACE("acpi_bus_scan_fixed");
1348
1349         if (!root)
1350                 return_VALUE(-ENODEV);
1351
1352         /*
1353          * Enumerate all fixed-feature devices.
1354          */
1355         if (acpi_fadt.pwr_button == 0) {
1356                 result = acpi_add_single_object(&device, acpi_root,
1357                                                 NULL,
1358                                                 ACPI_BUS_TYPE_POWER_BUTTON);
1359                 if (!result)
1360                         result = acpi_start_single_object(device);
1361         }
1362
1363         if (acpi_fadt.sleep_button == 0) {
1364                 result = acpi_add_single_object(&device, acpi_root,
1365                                                 NULL,
1366                                                 ACPI_BUS_TYPE_SLEEP_BUTTON);
1367                 if (!result)
1368                         result = acpi_start_single_object(device);
1369         }
1370
1371         return_VALUE(result);
1372 }
1373
1374 static int __init acpi_scan_init(void)
1375 {
1376         int result;
1377         struct acpi_bus_ops ops;
1378
1379         ACPI_FUNCTION_TRACE("acpi_scan_init");
1380
1381         if (acpi_disabled)
1382                 return_VALUE(0);
1383
1384         kset_register(&acpi_namespace_kset);
1385
1386         /*
1387          * Create the root device in the bus's device tree
1388          */
1389         result = acpi_add_single_object(&acpi_root, NULL, ACPI_ROOT_OBJECT,
1390                                         ACPI_BUS_TYPE_SYSTEM);
1391         if (result)
1392                 goto Done;
1393
1394         result = acpi_start_single_object(acpi_root);
1395
1396         /*
1397          * Enumerate devices in the ACPI namespace.
1398          */
1399         result = acpi_bus_scan_fixed(acpi_root);
1400         if (!result) {
1401                 memset(&ops, 0, sizeof(ops));
1402                 ops.acpi_op_add = 1;
1403                 ops.acpi_op_start = 1;
1404                 result = acpi_bus_scan(acpi_root, &ops);
1405         }
1406
1407         if (result)
1408                 acpi_device_unregister(acpi_root, ACPI_BUS_REMOVAL_NORMAL);
1409
1410       Done:
1411         return_VALUE(result);
1412 }
1413
1414 subsys_initcall(acpi_scan_init);