text: /*
   * scan.c - support for transforming the ACPI namespace into individual objects
   */
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/kernel.h>
  #include <linux/acpi.h>
  #include <linux/signal.h>
  #include <linux/kthread.h>
  #include <linux/dmi.h>
  
  #include <acpi/acpi_drivers.h>
  
  #include "internal.h"
  
  #define _COMPONENT		ACPI_BUS_COMPONENT
  ACPI_MODULE_NAME("scan");
  #define STRUCT_TO_INT(s)	(*((int*)&s))
  extern struct acpi_device *acpi_root;
  
  #define ACPI_BUS_CLASS			"system_bus"
  #define ACPI_BUS_HID			"LNXSYBUS"
  #define ACPI_BUS_DEVICE_NAME		"System Bus"
  
  #define ACPI_IS_ROOT_DEVICE(device)    (!(device)->parent)
  
  static const char *dummy_hid = "device";
  
  static LIST_HEAD(acpi_device_list);
  static LIST_HEAD(acpi_bus_id_list);
  DEFINE_MUTEX(acpi_device_lock);
  LIST_HEAD(acpi_wakeup_device_list);
  
  struct acpi_device_bus_id{
  	char bus_id[15];
  	unsigned int instance_no;
  	struct list_head node;
  };
  
  /*
   * Creates hid/cid(s) string needed for modalias and uevent
   * e.g. on a device with hid:IBM0001 and cid:ACPI0001 you get:
   * char *modalias: "acpi:IBM0001:ACPI0001"
  */
  static int create_modalias(struct acpi_device *acpi_dev, char *modalias,
  			   int size)
  {
  	int len;
  	int count;
  	struct acpi_hardware_id *id;
  
  	if (list_empty(&acpi_dev->pnp.ids))
  		return 0;
  
  	len = snprintf(modalias, size, "acpi:");
  	size -= len;
  
  	list_for_each_entry(id, &acpi_dev->pnp.ids, list) {
  		count = snprintf(&modalias[len], size, "%s:", id->id);
  		if (count < 0 || count >= size)
  			return -EINVAL;
  		len += count;
  		size -= count;
  	}
  
  	modalias[len] = '\0';
  	return len;
  }
  
  static ssize_t
  acpi_device_modalias_show(struct device *dev, struct device_attribute *attr, char *buf) {
  	struct acpi_device *acpi_dev = to_acpi_device(dev);
  	int len;
  
  	/* Device has no HID and no CID or string is >1024 */
  	len = create_modalias(acpi_dev, buf, 1024);
  	if (len <= 0)
  		return 0;
  	buf[len++] = '\n';
  	return len;
  }
  static DEVICE_ATTR(modalias, 0444, acpi_device_modalias_show, NULL);
  
  static void acpi_bus_hot_remove_device(void *context)
  {
  	struct acpi_device *device;
  	acpi_handle handle = context;
  	struct acpi_object_list arg_list;
  	union acpi_object arg;
  	acpi_status status = AE_OK;
  
  	if (acpi_bus_get_device(handle, &device))
  		return;
  
  	if (!device)
  		return;
  
  	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  		"Hot-removing device %s...\n", dev_name(&device->dev)));
  
  	if (acpi_bus_trim(device, 1)) {
  		printk(KERN_ERR PREFIX
  				"Removing device failed\n");
  		return;
  	}
  
  	/* power off device */
  	status = acpi_evaluate_object(handle, "_PS3", NULL, NULL);
  	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND)
  		printk(KERN_WARNING PREFIX
  				"Power-off device failed\n");
  
  	if (device->flags.lockable) {
  		arg_list.count = 1;
  		arg_list.pointer = &arg;
  		arg.type = ACPI_TYPE_INTEGER;
  		arg.integer.value = 0;
  		acpi_evaluate_object(handle, "_LCK", &arg_list, NULL);
  	}
  
  	arg_list.count = 1;
  	arg_list.pointer = &arg;
  	arg.type = ACPI_TYPE_INTEGER;
  	arg.integer.value = 1;
  
  	/*
  	 * TBD: _EJD support.
  	 */
  	status = acpi_evaluate_object(handle, "_EJ0", &arg_list, NULL);
  	if (ACPI_FAILURE(status))
  		printk(KERN_WARNING PREFIX
  				"Eject device failed\n");
  
  	return;
  }
  
  static ssize_t
  acpi_eject_store(struct device *d, struct device_attribute *attr,
  		const char *buf, size_t count)
  {
  	int ret = count;
  	acpi_status status;
  	acpi_object_type type = 0;
  	struct acpi_device *acpi_device = to_acpi_device(d);
  
  	if ((!count) || (buf[0] != '1')) {
  		return -EINVAL;
  	}
  #ifndef FORCE_EJECT
  	if (acpi_device->driver == NULL) {
  		ret = -ENODEV;
  		goto err;
  	}
  #endif
  	status = acpi_get_type(acpi_device->handle, &type);
  	if (ACPI_FAILURE(status) || (!acpi_device->flags.ejectable)) {
  		ret = -ENODEV;
  		goto err;
  	}
  
  	acpi_os_hotplug_execute(acpi_bus_hot_remove_device, acpi_device->handle);
  err:
  	return ret;
  }
  
  static DEVICE_ATTR(eject, 0200, NULL, acpi_eject_store);
  
  static ssize_t
  acpi_device_hid_show(struct device *dev, struct device_attribute *attr, char *buf) {
  	struct acpi_device *acpi_dev = to_acpi_device(dev);
  
  	return sprintf(buf, "%s\n", acpi_device_hid(acpi_dev));
  }
  static DEVICE_ATTR(hid, 0444, acpi_device_hid_show, NULL);
  
  static ssize_t
  acpi_device_path_show(struct device *dev, struct device_attribute *attr, char *buf) {
  	struct acpi_device *acpi_dev = to_acpi_device(dev);
  	struct acpi_buffer path = {ACPI_ALLOCATE_BUFFER, NULL};
  	int result;
  
  	result = acpi_get_name(acpi_dev->handle, ACPI_FULL_PATHNAME, &path);
  	if (result)
  		goto end;
  
  	result = sprintf(buf, "%s\n", (char*)path.pointer);
  	kfree(path.pointer);
  end:
  	return result;
  }
  static DEVICE_ATTR(path, 0444, acpi_device_path_show, NULL);
  
  static int acpi_device_setup_files(struct acpi_device *dev)
  {
  	acpi_status status;
  	acpi_handle temp;
  	int result = 0;
  
  	/*
  	 * Devices gotten from FADT don't have a "path" attribute
  	 */
  	if (dev->handle) {
  		result = device_create_file(&dev->dev, &dev_attr_path);
  		if (result)
  			goto end;
  	}
  
  	if (!list_empty(&dev->pnp.ids)) {
  		result = device_create_file(&dev->dev, &dev_attr_hid);
  		if (result)
  			goto end;
  
  		result = device_create_file(&dev->dev, &dev_attr_modalias);
  		if (result)
  			goto end;
  	}
  
          /*
           * If device has _EJ0, 'eject' file is created that is used to trigger
           * hot-removal function from userland.
           */
  	status = acpi_get_handle(dev->handle, "_EJ0", &temp);
  	if (ACPI_SUCCESS(status))
  		result = device_create_file(&dev->dev, &dev_attr_eject);
  end:
  	return result;
  }
  
  static void acpi_device_remove_files(struct acpi_device *dev)
  {
  	acpi_status status;
  	acpi_handle temp;
  
  	/*
  	 * If device has _EJ0, 'eject' file is created that is used to trigger
  	 * hot-removal function from userland.
  	 */
  	status = acpi_get_handle(dev->handle, "_EJ0", &temp);
  	if (ACPI_SUCCESS(status))
  		device_remove_file(&dev->dev, &dev_attr_eject);
  
  	device_remove_file(&dev->dev, &dev_attr_modalias);
  	device_remove_file(&dev->dev, &dev_attr_hid);
  	if (dev->handle)
  		device_remove_file(&dev->dev, &dev_attr_path);
  }
  /* --------------------------------------------------------------------------
  			ACPI Bus operations
     -------------------------------------------------------------------------- */
  
  int acpi_match_device_ids(struct acpi_device *device,
  			  const struct acpi_device_id *ids)
  {
  	const struct acpi_device_id *id;
  	struct acpi_hardware_id *hwid;
  
  	/*
  	 * If the device is not present, it is unnecessary to load device
  	 * driver for it.
  	 */
  	if (!device->status.present)
  		return -ENODEV;
  
  	for (id = ids; id->id[0]; id++)
  		list_for_each_entry(hwid, &device->pnp.ids, list)
  			if (!strcmp((char *) id->id, hwid->id))
  				return 0;
  
  	return -ENOENT;
  }
  EXPORT_SYMBOL(acpi_match_device_ids);
  
  static void acpi_free_ids(struct acpi_device *device)
  {
  	struct acpi_hardware_id *id, *tmp;
  
  	list_for_each_entry_safe(id, tmp, &device->pnp.ids, list) {
  		kfree(id->id);
  		kfree(id);
  	}
  }
  
  static void acpi_device_release(struct device *dev)
  {
  	struct acpi_device *acpi_dev = to_acpi_device(dev);
  
  	acpi_free_ids(acpi_dev);
  	kfree(acpi_dev);
  }
  
  static int acpi_device_suspend(struct device *dev, pm_message_t state)
  {
  	struct acpi_device *acpi_dev = to_acpi_device(dev);
  	struct acpi_driver *acpi_drv = acpi_dev->driver;
  
  	if (acpi_drv && acpi_drv->ops.suspend)
  		return acpi_drv->ops.suspend(acpi_dev, state);
  	return 0;
  }
  
  static int acpi_device_resume(struct device *dev)
  {
  	struct acpi_device *acpi_dev = to_acpi_device(dev);
  	struct acpi_driver *acpi_drv = acpi_dev->driver;
  
  	if (acpi_drv && acpi_drv->ops.resume)
  		return acpi_drv->ops.resume(acpi_dev);
  	return 0;
  }
  
  static int acpi_bus_match(struct device *dev, struct device_driver *drv)
  {
  	struct acpi_device *acpi_dev = to_acpi_device(dev);
  	struct acpi_driver *acpi_drv = to_acpi_driver(drv);
  
  	return !acpi_match_device_ids(acpi_dev, acpi_drv->ids);
  }
  
  static int acpi_device_uevent(struct device *dev, struct kobj_uevent_env *env)
  {
  	struct acpi_device *acpi_dev = to_acpi_device(dev);
  	int len;
  
  	if (list_empty(&acpi_dev->pnp.ids))
  		return 0;
  
  	if (add_uevent_var(env, "MODALIAS="))
  		return -ENOMEM;
  	len = create_modalias(acpi_dev, &env->buf[env->buflen - 1],
  			      sizeof(env->buf) - env->buflen);
  	if (len >= (sizeof(env->buf) - env->buflen))
  		return -ENOMEM;
  	env->buflen += len;
  	return 0;
  }
  
  static void acpi_device_notify(acpi_handle handle, u32 event, void *data)
  {
  	struct acpi_device *device = data;
  
  	device->driver->ops.notify(device, event);
  }
  
  static acpi_status acpi_device_notify_fixed(void *data)
  {
  	struct acpi_device *device = data;
  
  	/* Fixed hardware devices have no handles */
  	acpi_device_notify(NULL, ACPI_FIXED_HARDWARE_EVENT, device);
  	return AE_OK;
  }
  
  static int acpi_device_install_notify_handler(struct acpi_device *device)
  {
  	acpi_status status;
  
  	if (device->device_type == ACPI_BUS_TYPE_POWER_BUTTON)
  		status =
  		    acpi_install_fixed_event_handler(ACPI_EVENT_POWER_BUTTON,
  						     acpi_device_notify_fixed,
  						     device);
  	else if (device->device_type == ACPI_BUS_TYPE_SLEEP_BUTTON)
  		status =
  		    acpi_install_fixed_event_handler(ACPI_EVENT_SLEEP_BUTTON,
  						     acpi_device_notify_fixed,
  						     device);
  	else
  		status = acpi_install_notify_handler(device->handle,
  						     ACPI_DEVICE_NOTIFY,
  						     acpi_device_notify,
  						     device);
  
  	if (ACPI_FAILURE(status))
  		return -EINVAL;
  	return 0;
  }
  
  static void acpi_device_remove_notify_handler(struct acpi_device *device)
  {
  	if (device->device_type == ACPI_BUS_TYPE_POWER_BUTTON)
  		acpi_remove_fixed_event_handler(ACPI_EVENT_POWER_BUTTON,
  						acpi_device_notify_fixed);
  	else if (device->device_type == ACPI_BUS_TYPE_SLEEP_BUTTON)
  		acpi_remove_fixed_event_handler(ACPI_EVENT_SLEEP_BUTTON,
  						acpi_device_notify_fixed);
  	else
  		acpi_remove_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
  					   acpi_device_notify);
  }
  
  static int acpi_bus_driver_init(struct acpi_device *, struct acpi_driver *);
  static int acpi_start_single_object(struct acpi_device *);
  static int acpi_device_probe(struct device * dev)
  {
  	struct acpi_device *acpi_dev = to_acpi_device(dev);
  	struct acpi_driver *acpi_drv = to_acpi_driver(dev->driver);
  	int ret;
  
  	ret = acpi_bus_driver_init(acpi_dev, acpi_drv);
  	if (!ret) {
  		if (acpi_dev->bus_ops.acpi_op_start)
  			acpi_start_single_object(acpi_dev);
  
  		if (acpi_drv->ops.notify) {
  			ret = acpi_device_install_notify_handler(acpi_dev);
  			if (ret) {
  				if (acpi_drv->ops.remove)
  					acpi_drv->ops.remove(acpi_dev,
  						     acpi_dev->removal_type);
  				return ret;
  			}
  		}
  
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  			"Found driver [%s] for device [%s]\n",
  			acpi_drv->name, acpi_dev->pnp.bus_id));
  		get_device(dev);
  	}
  	return ret;
  }
  
  static int acpi_device_remove(struct device * dev)
  {
  	struct acpi_device *acpi_dev = to_acpi_device(dev);
  	struct acpi_driver *acpi_drv = acpi_dev->driver;
  
  	if (acpi_drv) {
  		if (acpi_drv->ops.notify)
  			acpi_device_remove_notify_handler(acpi_dev);
  		if (acpi_drv->ops.remove)
  			acpi_drv->ops.remove(acpi_dev, acpi_dev->removal_type);
  	}
  	acpi_dev->driver = NULL;
  	acpi_dev->driver_data = NULL;
  
  	put_device(dev);
  	return 0;
  }
  
  struct bus_type acpi_bus_type = {
  	.name		= "acpi",
  	.suspend	= acpi_device_suspend,
  	.resume		= acpi_device_resume,
  	.match		= acpi_bus_match,
  	.probe		= acpi_device_probe,
  	.remove		= acpi_device_remove,
  	.uevent		= acpi_device_uevent,
  };
  
  static int acpi_device_register(struct acpi_device *device)
  {
  	int result;
  	struct acpi_device_bus_id *acpi_device_bus_id, *new_bus_id;
  	int found = 0;
  
  	/*
  	 * Linkage
  	 * -------
  	 * Link this device to its parent and siblings.
  	 */
  	INIT_LIST_HEAD(&device->children);
  	INIT_LIST_HEAD(&device->node);
  	INIT_LIST_HEAD(&device->wakeup_list);
  
  	new_bus_id = kzalloc(sizeof(struct acpi_device_bus_id), GFP_KERNEL);
  	if (!new_bus_id) {
  		printk(KERN_ERR PREFIX "Memory allocation error\n");
  		return -ENOMEM;
  	}
  
  	mutex_lock(&acpi_device_lock);
  	/*
  	 * Find suitable bus_id and instance number in acpi_bus_id_list
  	 * If failed, create one and link it into acpi_bus_id_list
  	 */
  	list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node) {
  		if (!strcmp(acpi_device_bus_id->bus_id,
  			    acpi_device_hid(device))) {
  			acpi_device_bus_id->instance_no++;
  			found = 1;
  			kfree(new_bus_id);
  			break;
  		}
  	}
  	if (!found) {
  		acpi_device_bus_id = new_bus_id;
  		strcpy(acpi_device_bus_id->bus_id, acpi_device_hid(device));
  		acpi_device_bus_id->instance_no = 0;
  		list_add_tail(&acpi_device_bus_id->node, &acpi_bus_id_list);
  	}
  	dev_set_name(&device->dev, "%s:%02x", acpi_device_bus_id->bus_id, acpi_device_bus_id->instance_no);
  
  	if (device->parent)
  		list_add_tail(&device->node, &device->parent->children);
  
  	if (device->wakeup.flags.valid)
  		list_add_tail(&device->wakeup_list, &acpi_wakeup_device_list);
  	mutex_unlock(&acpi_device_lock);
  
  	if (device->parent)
  		device->dev.parent = &device->parent->dev;
  	device->dev.bus = &acpi_bus_type;
  	device->dev.release = &acpi_device_release;
  	result = device_register(&device->dev);
  	if (result) {
  		dev_err(&device->dev, "Error registering device\n");
  		goto end;
  	}
  
  	result = acpi_device_setup_files(device);
  	if (result)
  		printk(KERN_ERR PREFIX "Error creating sysfs interface for device %s\n",
  		       dev_name(&device->dev));
  
  	device->removal_type = ACPI_BUS_REMOVAL_NORMAL;
  	return 0;
  end:
  	mutex_lock(&acpi_device_lock);
  	if (device->parent)
  		list_del(&device->node);
  	list_del(&device->wakeup_list);
  	mutex_unlock(&acpi_device_lock);
  	return result;
  }
  
  static void acpi_device_unregister(struct acpi_device *device, int type)
  {
  	mutex_lock(&acpi_device_lock);
  	if (device->parent)
  		list_del(&device->node);
  
  	list_del(&device->wakeup_list);
  	mutex_unlock(&acpi_device_lock);
  
  	acpi_detach_data(device->handle, acpi_bus_data_handler);
  
  	acpi_device_remove_files(device);
  	device_unregister(&device->dev);
  }
  
  /* --------------------------------------------------------------------------
                                   Driver Management
     -------------------------------------------------------------------------- */
  /**
   * acpi_bus_driver_init - add a device to a driver
   * @device: the device to add and initialize
   * @driver: driver for the device
   *
   * Used to initialize a device via its device driver.  Called whenever a
   * driver is bound to a device.  Invokes the driver's add() ops.
   */
  static int
  acpi_bus_driver_init(struct acpi_device *device, struct acpi_driver *driver)
  {
  	int result = 0;
  
  	if (!device || !driver)
  		return -EINVAL;
  
  	if (!driver->ops.add)
  		return -ENOSYS;
  
  	result = driver->ops.add(device);
  	if (result) {
  		device->driver = NULL;
  		device->driver_data = NULL;
  		return result;
  	}
  
  	device->driver = driver;
  
  	/*
  	 * TBD - Configuration Management: Assign resources to device based
  	 * upon possible configuration and currently allocated resources.
  	 */
  
  	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  			  "Driver successfully bound to device\n"));
  	return 0;
  }
  
  static int acpi_start_single_object(struct acpi_device *device)
  {
  	int result = 0;
  	struct acpi_driver *driver;
  
  
  	if (!(driver = device->driver))
  		return 0;
  
  	if (driver->ops.start) {
  		result = driver->ops.start(device);
  		if (result && driver->ops.remove)
  			driver->ops.remove(device, ACPI_BUS_REMOVAL_NORMAL);
  	}
  
  	return result;
  }
  
  /**
   * acpi_bus_register_driver - register a driver with the ACPI bus
   * @driver: driver being registered
   *
   * Registers a driver with the ACPI bus.  Searches the namespace for all
   * devices that match the driver's criteria and binds.  Returns zero for
   * success or a negative error status for failure.
   */
  int acpi_bus_register_driver(struct acpi_driver *driver)
  {
  	int ret;
  
  	if (acpi_disabled)
  		return -ENODEV;
  	driver->drv.name = driver->name;
  	driver->drv.bus = &acpi_bus_type;
  	driver->drv.owner = driver->owner;
  
  	ret = driver_register(&driver->drv);
  	return ret;
  }
  
  EXPORT_SYMBOL(acpi_bus_register_driver);
  
  /**
   * acpi_bus_unregister_driver - unregisters a driver with the APIC bus
   * @driver: driver to unregister
   *
   * Unregisters a driver with the ACPI bus.  Searches the namespace for all
   * devices that match the driver's criteria and unbinds.
   */
  void acpi_bus_unregister_driver(struct acpi_driver *driver)
  {
  	driver_unregister(&driver->drv);
  }
  
  EXPORT_SYMBOL(acpi_bus_unregister_driver);
  
  /* --------------------------------------------------------------------------
                                   Device Enumeration
     -------------------------------------------------------------------------- */
  static struct acpi_device *acpi_bus_get_parent(acpi_handle handle)
  {
  	acpi_status status;
  	int ret;
  	struct acpi_device *device;
  
  	/*
  	 * Fixed hardware devices do not appear in the namespace and do not
  	 * have handles, but we fabricate acpi_devices for them, so we have
  	 * to deal with them specially.
  	 */
  	if (handle == NULL)
  		return acpi_root;
  
  	do {
  		status = acpi_get_parent(handle, &handle);
  		if (status == AE_NULL_ENTRY)
  			return NULL;
  		if (ACPI_FAILURE(status))
  			return acpi_root;
  
  		ret = acpi_bus_get_device(handle, &device);
  		if (ret == 0)
  			return device;
  	} while (1);
  }
  
  acpi_status
  acpi_bus_get_ejd(acpi_handle handle, acpi_handle *ejd)
  {
  	acpi_status status;
  	acpi_handle tmp;
  	struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
  	union acpi_object *obj;
  
  	status = acpi_get_handle(handle, "_EJD", &tmp);
  	if (ACPI_FAILURE(status))
  		return status;
  
  	status = acpi_evaluate_object(handle, "_EJD", NULL, &buffer);
  	if (ACPI_SUCCESS(status)) {
  		obj = buffer.pointer;
  		status = acpi_get_handle(ACPI_ROOT_OBJECT, obj->string.pointer,
  					 ejd);
  		kfree(buffer.pointer);
  	}
  	return status;
  }
  EXPORT_SYMBOL_GPL(acpi_bus_get_ejd);
  
  void acpi_bus_data_handler(acpi_handle handle, void *context)
  {
  
  	/* TBD */
  
  	return;
  }
  
  static int acpi_bus_get_perf_flags(struct acpi_device *device)
  {
  	device->performance.state = ACPI_STATE_UNKNOWN;
  	return 0;
  }
  
  static acpi_status
  acpi_bus_extract_wakeup_device_power_package(acpi_handle handle,
  					     struct acpi_device_wakeup *wakeup)
  {
  	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
  	union acpi_object *package = NULL;
  	union acpi_object *element = NULL;
  	acpi_status status;
  	int i = 0;
  
  	if (!wakeup)
  		return AE_BAD_PARAMETER;
  
  	/* _PRW */
  	status = acpi_evaluate_object(handle, "_PRW", NULL, &buffer);
  	if (ACPI_FAILURE(status)) {
  		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRW"));
  		return status;
  	}
  
  	package = (union acpi_object *)buffer.pointer;
  
  	if (!package || (package->package.count < 2)) {
  		status = AE_BAD_DATA;
  		goto out;
  	}
  
  	element = &(package->package.elements[0]);
  	if (!element) {
  		status = AE_BAD_DATA;
  		goto out;
  	}
  	if (element->type == ACPI_TYPE_PACKAGE) {
  		if ((element->package.count < 2) ||
  		    (element->package.elements[0].type !=
  		     ACPI_TYPE_LOCAL_REFERENCE)
  		    || (element->package.elements[1].type != ACPI_TYPE_INTEGER)) {
  			status = AE_BAD_DATA;
  			goto out;
  		}
  		wakeup->gpe_device =
  		    element->package.elements[0].reference.handle;
  		wakeup->gpe_number =
  		    (u32) element->package.elements[1].integer.value;
  	} else if (element->type == ACPI_TYPE_INTEGER) {
  		wakeup->gpe_device = NULL;
  		wakeup->gpe_number = element->integer.value;
  	} else {
  		status = AE_BAD_DATA;
  		goto out;
  	}
  
  	element = &(package->package.elements[1]);
  	if (element->type != ACPI_TYPE_INTEGER) {
  		status = AE_BAD_DATA;
  		goto out;
  	}
  	wakeup->sleep_state = element->integer.value;
  
  	if ((package->package.count - 2) > ACPI_MAX_HANDLES) {
  		status = AE_NO_MEMORY;
  		goto out;
  	}
  	wakeup->resources.count = package->package.count - 2;
  	for (i = 0; i < wakeup->resources.count; i++) {
  		element = &(package->package.elements[i + 2]);
  		if (element->type != ACPI_TYPE_LOCAL_REFERENCE) {
  			status = AE_BAD_DATA;
  			goto out;
  		}
  
  		wakeup->resources.handles[i] = element->reference.handle;
  	}
  
  	acpi_setup_gpe_for_wake(handle, wakeup->gpe_device, wakeup->gpe_number);
  
   out:
  	kfree(buffer.pointer);
  
  	return status;
  }
  
  static void acpi_bus_set_run_wake_flags(struct acpi_device *device)
  {
  	struct acpi_device_id button_device_ids[] = {
  		{"PNP0C0D", 0},
  		{"PNP0C0C", 0},
  		{"PNP0C0E", 0},
  		{"", 0},
  	};
  	acpi_status status;
  	acpi_event_status event_status;
  
  	device->wakeup.flags.notifier_present = 0;
  
  	/* Power button, Lid switch always enable wakeup */
  	if (!acpi_match_device_ids(device, button_device_ids)) {
  		device->wakeup.flags.run_wake = 1;
  		device_set_wakeup_capable(&device->dev, true);
  		return;
  	}
  
  	status = acpi_get_gpe_status(device->wakeup.gpe_device,
  					device->wakeup.gpe_number,
  						&event_status);
  	if (status == AE_OK)
  		device->wakeup.flags.run_wake =
  				!!(event_status & ACPI_EVENT_FLAG_HANDLE);
  }
  
  static void acpi_bus_get_wakeup_device_flags(struct acpi_device *device)
  {
  	acpi_handle temp;
  	acpi_status status = 0;
  	int psw_error;
  
  	/* Presence of _PRW indicates wake capable */
  	status = acpi_get_handle(device->handle, "_PRW", &temp);
  	if (ACPI_FAILURE(status))
  		return;
  
  	status = acpi_bus_extract_wakeup_device_power_package(device->handle,
  							      &device->wakeup);
  	if (ACPI_FAILURE(status)) {
  		ACPI_EXCEPTION((AE_INFO, status, "Extracting _PRW package"));
  		return;
  	}
  
  	device->wakeup.flags.valid = 1;
  	device->wakeup.prepare_count = 0;
  	acpi_bus_set_run_wake_flags(device);
  	/* Call _PSW/_DSW object to disable its ability to wake the sleeping
  	 * system for the ACPI device with the _PRW object.
  	 * The _PSW object is depreciated in ACPI 3.0 and is replaced by _DSW.
  	 * So it is necessary to call _DSW object first. Only when it is not
  	 * present will the _PSW object used.
  	 */
  	psw_error = acpi_device_sleep_wake(device, 0, 0, 0);
  	if (psw_error)
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  				"error in _DSW or _PSW evaluation\n"));
  }
  
  static void acpi_bus_add_power_resource(acpi_handle handle);
  
  static int acpi_bus_get_power_flags(struct acpi_device *device)
  {
  	acpi_status status = 0;
  	acpi_handle handle = NULL;
  	u32 i = 0;
  
  
  	/*
  	 * Power Management Flags
  	 */
  	status = acpi_get_handle(device->handle, "_PSC", &handle);
  	if (ACPI_SUCCESS(status))
  		device->power.flags.explicit_get = 1;
  	status = acpi_get_handle(device->handle, "_IRC", &handle);
  	if (ACPI_SUCCESS(status))
  		device->power.flags.inrush_current = 1;
  
  	/*
  	 * Enumerate supported power management states
  	 */
  	for (i = ACPI_STATE_D0; i <= ACPI_STATE_D3; i++) {
  		struct acpi_device_power_state *ps = &device->power.states[i];
  		char object_name[5] = { '_', 'P', 'R', '0' + i, '\0' };
  
  		/* Evaluate "_PRx" to se if power resources are referenced */
  		acpi_evaluate_reference(device->handle, object_name, NULL,
  					&ps->resources);
  		if (ps->resources.count) {
  			int j;
  
  			device->power.flags.power_resources = 1;
  			ps->flags.valid = 1;
  			for (j = 0; j < ps->resources.count; j++)
  				acpi_bus_add_power_resource(ps->resources.handles[j]);
  		}
  
  		/* Evaluate "_PSx" to see if we can do explicit sets */
  		object_name[2] = 'S';
  		status = acpi_get_handle(device->handle, object_name, &handle);
  		if (ACPI_SUCCESS(status)) {
  			ps->flags.explicit_set = 1;
  			ps->flags.valid = 1;
  		}
  
  		/* State is valid if we have some power control */
  		if (ps->resources.count || ps->flags.explicit_set)
  			ps->flags.valid = 1;
  
  		ps->power = -1;	/* Unknown - driver assigned */
  		ps->latency = -1;	/* Unknown - driver assigned */
  	}
  
  	/* Set defaults for D0 and D3 states (always valid) */
  	device->power.states[ACPI_STATE_D0].flags.valid = 1;
  	device->power.states[ACPI_STATE_D0].power = 100;
  	device->power.states[ACPI_STATE_D3].flags.valid = 1;
  	device->power.states[ACPI_STATE_D3].power = 0;
  
  	acpi_bus_init_power(device);
  
  	return 0;
  }
  
  static int acpi_bus_get_flags(struct acpi_device *device)
  {
  	acpi_status status = AE_OK;
  	acpi_handle temp = NULL;
  
  
  	/* Presence of _STA indicates 'dynamic_status' */
  	status = acpi_get_handle(device->handle, "_STA", &temp);
  	if (ACPI_SUCCESS(status))
  		device->flags.dynamic_status = 1;
  
  	/* Presence of _RMV indicates 'removable' */
  	status = acpi_get_handle(device->handle, "_RMV", &temp);
  	if (ACPI_SUCCESS(status))
  		device->flags.removable = 1;
  
  	/* Presence of _EJD|_EJ0 indicates 'ejectable' */
  	status = acpi_get_handle(device->handle, "_EJD", &temp);
  	if (ACPI_SUCCESS(status))
  		device->flags.ejectable = 1;
  	else {
  		status = acpi_get_handle(device->handle, "_EJ0", &temp);
  		if (ACPI_SUCCESS(status))
  			device->flags.ejectable = 1;
  	}
  
  	/* Presence of _LCK indicates 'lockable' */
  	status = acpi_get_handle(device->handle, "_LCK", &temp);
  	if (ACPI_SUCCESS(status))
  		device->flags.lockable = 1;
  
  	/* Power resources cannot be power manageable. */
  	if (device->device_type == ACPI_BUS_TYPE_POWER)
  		return 0;
  
  	/* Presence of _PS0|_PR0 indicates 'power manageable' */
  	status = acpi_get_handle(device->handle, "_PS0", &temp);
  	if (ACPI_FAILURE(status))
  		status = acpi_get_handle(device->handle, "_PR0", &temp);
  	if (ACPI_SUCCESS(status))
  		device->flags.power_manageable = 1;
  
  	/* TBD: Performance management */
  
  	return 0;
  }
  
  static void acpi_device_get_busid(struct acpi_device *device)
  {
  	char bus_id[5] = { '?', 0 };
  	struct acpi_buffer buffer = { sizeof(bus_id), bus_id };
  	int i = 0;
  
  	/*
  	 * Bus ID
  	 * ------
  	 * The device's Bus ID is simply the object name.
  	 * TBD: Shouldn't this value be unique (within the ACPI namespace)?
  	 */
  	if (ACPI_IS_ROOT_DEVICE(device)) {
  		strcpy(device->pnp.bus_id, "ACPI");
  		return;
  	}
  
  	switch (device->device_type) {
  	case ACPI_BUS_TYPE_POWER_BUTTON:
  		strcpy(device->pnp.bus_id, "PWRF");
  		break;
  	case ACPI_BUS_TYPE_SLEEP_BUTTON:
  		strcpy(device->pnp.bus_id, "SLPF");
  		break;
  	default:
  		acpi_get_name(device->handle, ACPI_SINGLE_NAME, &buffer);
  		/* Clean up trailing underscores (if any) */
  		for (i = 3; i > 1; i--) {
  			if (bus_id[i] == '_')
  				bus_id[i] = '\0';
  			else
  				break;
  		}
  		strcpy(device->pnp.bus_id, bus_id);
  		break;
  	}
  }
  
  /*
   * acpi_bay_match - see if a device is an ejectable driver bay
   *
   * If an acpi object is ejectable and has one of the ACPI ATA methods defined,
   * then we can safely call it an ejectable drive bay
   */
  static int acpi_bay_match(struct acpi_device *device){
  	acpi_status status;
  	acpi_handle handle;
  	acpi_handle tmp;
  	acpi_handle phandle;
  
  	handle = device->handle;
  
  	status = acpi_get_handle(handle, "_EJ0", &tmp);
  	if (ACPI_FAILURE(status))
  		return -ENODEV;
  
  	if ((ACPI_SUCCESS(acpi_get_handle(handle, "_GTF", &tmp))) ||
  		(ACPI_SUCCESS(acpi_get_handle(handle, "_GTM", &tmp))) ||
  		(ACPI_SUCCESS(acpi_get_handle(handle, "_STM", &tmp))) ||
  		(ACPI_SUCCESS(acpi_get_handle(handle, "_SDD", &tmp))))
  		return 0;
  
  	if (acpi_get_parent(handle, &phandle))
  		return -ENODEV;
  
          if ((ACPI_SUCCESS(acpi_get_handle(phandle, "_GTF", &tmp))) ||
                  (ACPI_SUCCESS(acpi_get_handle(phandle, "_GTM", &tmp))) ||
                  (ACPI_SUCCESS(acpi_get_handle(phandle, "_STM", &tmp))) ||
                  (ACPI_SUCCESS(acpi_get_handle(phandle, "_SDD", &tmp))))
                  return 0;
  
  	return -ENODEV;
  }
  
  /*
   * acpi_dock_match - see if a device has a _DCK method
   */
  static int acpi_dock_match(struct acpi_device *device)
  {
  	acpi_handle tmp;
  	return acpi_get_handle(device->handle, "_DCK", &tmp);
  }
  
  const char *acpi_device_hid(struct acpi_device *device)
  {
  	struct acpi_hardware_id *hid;
  
  	if (list_empty(&device->pnp.ids))
  		return dummy_hid;
  
  	hid = list_first_entry(&device->pnp.ids, struct acpi_hardware_id, list);
  	return hid->id;
  }
  EXPORT_SYMBOL(acpi_device_hid);
  
  static void acpi_add_id(struct acpi_device *device, const char *dev_id)
  {
  	struct acpi_hardware_id *id;
  
  	id = kmalloc(sizeof(*id), GFP_KERNEL);
  	if (!id)
  		return;
  
  	id->id = kmalloc(strlen(dev_id) + 1, GFP_KERNEL);
  	if (!id->id) {
  		kfree(id);
  		return;
  	}
  
  	strcpy(id->id, dev_id);
  	list_add_tail(&id->list, &device->pnp.ids);
  }
  
  /*
   * Old IBM workstations have a DSDT bug wherein the SMBus object
   * lacks the SMBUS01 HID and the methods do not have the necessary "_"
   * prefix.  Work around this.
   */
  static int acpi_ibm_smbus_match(struct acpi_device *device)
  {
  	acpi_handle h_dummy;
  	struct acpi_buffer path = {ACPI_ALLOCATE_BUFFER, NULL};
  	int result;
  
  	if (!dmi_name_in_vendors("IBM"))
  		return -ENODEV;
  
  	/* Look for SMBS object */
  	result = acpi_get_name(device->handle, ACPI_SINGLE_NAME, &path);
  	if (result)
  		return result;
  
  	if (strcmp("SMBS", path.pointer)) {
  		result = -ENODEV;
  		goto out;
  	}
  
  	/* Does it have the necessary (but misnamed) methods? */
  	result = -ENODEV;
  	if (ACPI_SUCCESS(acpi_get_handle(device->handle, "SBI", &h_dummy)) &&
  	    ACPI_SUCCESS(acpi_get_handle(device->handle, "SBR", &h_dummy)) &&
  	    ACPI_SUCCESS(acpi_get_handle(device->handle, "SBW", &h_dummy)))
  		result = 0;
  out:
  	kfree(path.pointer);
  	return result;
  }
  
  static void acpi_device_set_id(struct acpi_device *device)
  {
  	acpi_status status;
  	struct acpi_device_info *info;
  	struct acpica_device_id_list *cid_list;
  	int i;
  
  	switch (device->device_type) {
  	case ACPI_BUS_TYPE_DEVICE:
  		if (ACPI_IS_ROOT_DEVICE(device)) {
  			acpi_add_id(device, ACPI_SYSTEM_HID);
  			break;
  		}
  
  		status = acpi_get_object_info(device->handle, &info);
  		if (ACPI_FAILURE(status)) {
  			printk(KERN_ERR PREFIX "%s: Error reading device info\n", __func__);
  			return;
  		}
  
  		if (info->valid & ACPI_VALID_HID)
  			acpi_add_id(device, info->hardware_id.string);
  		if (info->valid & ACPI_VALID_CID) {
  			cid_list = &info->compatible_id_list;
  			for (i = 0; i < cid_list->count; i++)
  				acpi_add_id(device, cid_list->ids[i].string);
  		}
  		if (info->valid & ACPI_VALID_ADR) {
  			device->pnp.bus_address = info->address;
  			device->flags.bus_address = 1;
  		}
  
  		kfree(info);
  
  		/*
  		 * Some devices don't reliably have _HIDs & _CIDs, so add
  		 * synthetic HIDs to make sure drivers can find them.
  		 */
  		if (acpi_is_video_device(device))
  			acpi_add_id(device, ACPI_VIDEO_HID);
  		else if (ACPI_SUCCESS(acpi_bay_match(device)))
  			acpi_add_id(device, ACPI_BAY_HID);
  		else if (ACPI_SUCCESS(acpi_dock_match(device)))
  			acpi_add_id(device, ACPI_DOCK_HID);
  		else if (!acpi_ibm_smbus_match(device))
  			acpi_add_id(device, ACPI_SMBUS_IBM_HID);
  		else if (!acpi_device_hid(device) &&
  			 ACPI_IS_ROOT_DEVICE(device->parent)) {
  			acpi_add_id(device, ACPI_BUS_HID); /* \_SB, LNXSYBUS */
  			strcpy(device->pnp.device_name, ACPI_BUS_DEVICE_NAME);
  			strcpy(device->pnp.device_class, ACPI_BUS_CLASS);
  		}
  
  		break;
  	case ACPI_BUS_TYPE_POWER:
  		acpi_add_id(device, ACPI_POWER_HID);
  		break;
  	case ACPI_BUS_TYPE_PROCESSOR:
  		acpi_add_id(device, ACPI_PROCESSOR_OBJECT_HID);
  		break;
  	case ACPI_BUS_TYPE_THERMAL:
  		acpi_add_id(device, ACPI_THERMAL_HID);
  		break;
  	case ACPI_BUS_TYPE_POWER_BUTTON:
  		acpi_add_id(device, ACPI_BUTTON_HID_POWERF);
  		break;
  	case ACPI_BUS_TYPE_SLEEP_BUTTON:
  		acpi_add_id(device, ACPI_BUTTON_HID_SLEEPF);
  		break;
  	}
  }
  
  static int acpi_device_set_context(struct acpi_device *device)
  {
  	acpi_status status;
  
  	/*
  	 * Context
  	 * -------
  	 * Attach this 'struct acpi_device' to the ACPI object.  This makes
  	 * resolutions from handle->device very efficient.  Fixed hardware
  	 * devices have no handles, so we skip them.
  	 */
  	if (!device->handle)
  		return 0;
  
  	status = acpi_attach_data(device->handle,
  				  acpi_bus_data_handler, device);
  	if (ACPI_SUCCESS(status))
  		return 0;
  
  	printk(KERN_ERR PREFIX "Error attaching device data\n");
  	return -ENODEV;
  }
  
  static int acpi_bus_remove(struct acpi_device *dev, int rmdevice)
  {
  	if (!dev)
  		return -EINVAL;
  
  	dev->removal_type = ACPI_BUS_REMOVAL_EJECT;
  	device_release_driver(&dev->dev);
  
  	if (!rmdevice)
  		return 0;
  
  	/*
  	 * unbind _ADR-Based Devices when hot removal
  	 */
  	if (dev->flags.bus_address) {
  		if ((dev->parent) && (dev->parent->ops.unbind))
  			dev->parent->ops.unbind(dev);
  	}
  	acpi_device_unregister(dev, ACPI_BUS_REMOVAL_EJECT);
  
  	return 0;
  }
  
  static int acpi_add_single_object(struct acpi_device **child,
  				  acpi_handle handle, int type,
  				  unsigned long long sta,
  				  struct acpi_bus_ops *ops)
  {
  	int result;
  	struct acpi_device *device;
  	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
  
  	device = kzalloc(sizeof(struct acpi_device), GFP_KERNEL);
  	if (!device) {
  		printk(KERN_ERR PREFIX "Memory allocation error\n");
  		return -ENOMEM;
  	}
  
  	INIT_LIST_HEAD(&device->pnp.ids);
  	device->device_type = type;
  	device->handle = handle;
  	device->parent = acpi_bus_get_parent(handle);
  	device->bus_ops = *ops; /* workround for not call .start */
  	STRUCT_TO_INT(device->status) = sta;
  
  	acpi_device_get_busid(device);
  
  	/*
  	 * Flags
  	 * -----
  	 * Note that we only look for object handles -- cannot evaluate objects
  	 * until we know the device is present and properly initialized.
  	 */
  	result = acpi_bus_get_flags(device);
  	if (result)
  		goto end;
  
  	/*
  	 * Initialize Device
  	 * -----------------
  	 * TBD: Synch with Core's enumeration/initialization process.
  	 */
  	acpi_device_set_id(device);
  
  	/*
  	 * Power Management
  	 * ----------------
  	 */
  	if (device->flags.power_manageable) {
  		result = acpi_bus_get_power_flags(device);
  		if (result)
  			goto end;
  	}
  
  	/*
  	 * Wakeup device management
  	 *-----------------------
  	 */
  	acpi_bus_get_wakeup_device_flags(device);
  
  	/*
  	 * Performance Management
  	 * ----------------------
  	 */
  	if (device->flags.performance_manageable) {
  		result = acpi_bus_get_perf_flags(device);
  		if (result)
  			goto end;
  	}
  
  	if ((result = acpi_device_set_context(device)))
  		goto end;
  
  	result = acpi_device_register(device);
  
  	/*
  	 * Bind _ADR-Based Devices when hot add
  	 */
  	if (device->flags.bus_address) {
  		if (device->parent && device->parent->ops.bind)
  			device->parent->ops.bind(device);
  	}
  
  end:
  	if (!result) {
  		acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  			"Adding %s [%s] parent %s\n", dev_name(&device->dev),
  			 (char *) buffer.pointer,
  			 device->parent ? dev_name(&device->parent->dev) :
  					  "(null)"));
  		kfree(buffer.pointer);
  		*child = device;
  	} else
  		acpi_device_release(&device->dev);
  
  	return result;
  }
  
  #define ACPI_STA_DEFAULT (ACPI_STA_DEVICE_PRESENT | ACPI_STA_DEVICE_ENABLED | \
  			  ACPI_STA_DEVICE_UI      | ACPI_STA_DEVICE_FUNCTIONING)
  
  static void acpi_bus_add_power_resource(acpi_handle handle)
  {
  	struct acpi_bus_ops ops = {
  		.acpi_op_add = 1,
  		.acpi_op_start = 1,
  	};
  	struct acpi_device *device = NULL;
  
  	acpi_bus_get_device(handle, &device);
  	if (!device)
  		acpi_add_single_object(&device, handle, ACPI_BUS_TYPE_POWER,
  					ACPI_STA_DEFAULT, &ops);
  }
  
  static int acpi_bus_type_and_status(acpi_handle handle, int *type,
  				    unsigned long long *sta)
  {
  	acpi_status status;
  	acpi_object_type acpi_type;
  
  	status = acpi_get_type(handle, &acpi_type);
  	if (ACPI_FAILURE(status))
  		return -ENODEV;
  
  	switch (acpi_type) {
  	case ACPI_TYPE_ANY:		/* for ACPI_ROOT_OBJECT */
  	case ACPI_TYPE_DEVICE:
  		*type = ACPI_BUS_TYPE_DEVICE;
  		status = acpi_bus_get_status_handle(handle, sta);
  		if (ACPI_FAILURE(status))
  			return -ENODEV;
  		break;
  	case ACPI_TYPE_PROCESSOR:
  		*type = ACPI_BUS_TYPE_PROCESSOR;
  		status = acpi_bus_get_status_handle(handle, sta);
  		if (ACPI_FAILURE(status))
  			return -ENODEV;
  		break;
  	case ACPI_TYPE_THERMAL:
  		*type = ACPI_BUS_TYPE_THERMAL;
  		*sta = ACPI_STA_DEFAULT;
  		break;
  	case ACPI_TYPE_POWER:
  		*type = ACPI_BUS_TYPE_POWER;
  		*sta = ACPI_STA_DEFAULT;
  		break;
  	default:
  		return -ENODEV;
  	}
  
  	return 0;
  }
  
  static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl,
  				      void *context, void **return_value)
  {
  	struct acpi_bus_ops *ops = context;
  	int type;
  	unsigned long long sta;
  	struct acpi_device *device;
  	acpi_status status;
  	int result;
  
  	result = acpi_bus_type_and_status(handle, &type, &sta);
  	if (result)
  		return AE_OK;
  
  	if (!(sta & ACPI_STA_DEVICE_PRESENT) &&
  	    !(sta & ACPI_STA_DEVICE_FUNCTIONING)) {
  		struct acpi_device_wakeup wakeup;
  		acpi_handle temp;
  
  		status = acpi_get_handle(handle, "_PRW", &temp);
  		if (ACPI_SUCCESS(status))
  			acpi_bus_extract_wakeup_device_power_package(handle,
  								     &wakeup);
  		return AE_CTRL_DEPTH;
  	}
  
  	/*
  	 * We may already have an acpi_device from a previous enumeration.  If
  	 * so, we needn't add it again, but we may still have to start it.
  	 */
  	device = NULL;
  	acpi_bus_get_device(handle, &device);
  	if (ops->acpi_op_add && !device)
  		acpi_add_single_object(&device, handle, type, sta, ops);
  
  	if (!device)
  		return AE_CTRL_DEPTH;
  
  	if (ops->acpi_op_start && !(ops->acpi_op_add)) {
  		status = acpi_start_single_object(device);
  		if (ACPI_FAILURE(status))
  			return AE_CTRL_DEPTH;
  	}
  
  	if (!*return_value)
  		*return_value = device;
  	return AE_OK;
  }
  
  static int acpi_bus_scan(acpi_handle handle, struct acpi_bus_ops *ops,
  			 struct acpi_device **child)
  {
  	acpi_status status;
  	void *device = NULL;
  
  	status = acpi_bus_check_add(handle, 0, ops, &device);
  	if (ACPI_SUCCESS(status))
  		acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
  				    acpi_bus_check_add, NULL, ops, &device);
  
  	if (child)
  		*child = device;
  
  	if (device)
  		return 0;
  	else
  		return -ENODEV;
  }
  
  /*
   * acpi_bus_add and acpi_bus_start
   *
   * scan a given ACPI tree and (probably recently hot-plugged)
   * create and add or starts found devices.
   *
   * If no devices were found -ENODEV is returned which does not
   * mean that this is a real error, there just have been no suitable
   * ACPI objects in the table trunk from which the kernel could create
   * a device and add/start an appropriate driver.
   */
  
  int
  acpi_bus_add(struct acpi_device **child,
  	     struct acpi_device *parent, acpi_handle handle, int type)
  {
  	struct acpi_bus_ops ops;
  
  	memset(&ops, 0, sizeof(ops));
  	ops.acpi_op_add = 1;
  
  	return acpi_bus_scan(handle, &ops, child);
  }
  EXPORT_SYMBOL(acpi_bus_add);
  
  int acpi_bus_start(struct acpi_device *device)
  {
  	struct acpi_bus_ops ops;
  	int result;
  
  	if (!device)
  		return -EINVAL;
  
  	memset(&ops, 0, sizeof(ops));
  	ops.acpi_op_start = 1;
  
  	result = acpi_bus_scan(device->handle, &ops, NULL);
  
  	acpi_update_all_gpes();
  
  	return result;
  }
  EXPORT_SYMBOL(acpi_bus_start);
  
  int acpi_bus_trim(struct acpi_device *start, int rmdevice)
  {
  	acpi_status status;
  	struct acpi_device *parent, *child;
  	acpi_handle phandle, chandle;
  	acpi_object_type type;
  	u32 level = 1;
  	int err = 0;
  
  	parent = start;
  	phandle = start->handle;
  	child = chandle = NULL;
  
  	while ((level > 0) && parent && (!err)) {
  		status = acpi_get_next_object(ACPI_TYPE_ANY, phandle,
  					      chandle, &chandle);
  
  		/*
  		 * If this scope is exhausted then move our way back up.
  		 */
  		if (ACPI_FAILURE(status)) {
  			level--;
  			chandle = phandle;
  			acpi_get_parent(phandle, &phandle);
  			child = parent;
  			parent = parent->parent;
  
  			if (level == 0)
  				err = acpi_bus_remove(child, rmdevice);
  			else
  				err = acpi_bus_remove(child, 1);
  
  			continue;
  		}
  
  		status = acpi_get_type(chandle, &type);
  		if (ACPI_FAILURE(status)) {
  			continue;
  		}
  		/*
  		 * If there is a device corresponding to chandle then
  		 * parse it (depth-first).
  		 */
  		if (acpi_bus_get_device(chandle, &child) == 0) {
  			level++;
  			phandle = chandle;
  			chandle = NULL;
  			parent = child;
  		}
  		continue;
  	}
  	return err;
  }
  EXPORT_SYMBOL_GPL(acpi_bus_trim);
  
  static int acpi_bus_scan_fixed(void)
  {
  	int result = 0;
  	struct acpi_device *device = NULL;
  	struct acpi_bus_ops ops;
  
  	memset(&ops, 0, sizeof(ops));
  	ops.acpi_op_add = 1;
  	ops.acpi_op_start = 1;
  
  	/*
  	 * Enumerate all fixed-feature devices.
  	 */
  	if ((acpi_gbl_FADT.flags & ACPI_FADT_POWER_BUTTON) == 0) {
  		result = acpi_add_single_object(&device, NULL,
  						ACPI_BUS_TYPE_POWER_BUTTON,
  						ACPI_STA_DEFAULT,
  						&ops);
  	}
  
  	if ((acpi_gbl_FADT.flags & ACPI_FADT_SLEEP_BUTTON) == 0) {
  		result = acpi_add_single_object(&device, NULL,
  						ACPI_BUS_TYPE_SLEEP_BUTTON,
  						ACPI_STA_DEFAULT,
  						&ops);
  	}
  
  	return result;
  }
  
  int __init acpi_scan_init(void)
  {
  	int result;
  	struct acpi_bus_ops ops;
  
  	memset(&ops, 0, sizeof(ops));
  	ops.acpi_op_add = 1;
  	ops.acpi_op_start = 1;
  
  	result = bus_register(&acpi_bus_type);
  	if (result) {
  		/* We don't want to quit even if we failed to add suspend/resume */
  		printk(KERN_ERR PREFIX "Could not register bus type\n");
  	}
  
  	acpi_power_init();
  
  	/*
  	 * Enumerate devices in the ACPI namespace.
  	 */
  	result = acpi_bus_scan(ACPI_ROOT_OBJECT, &ops, &acpi_root);
  
  	if (!result)
  		result = acpi_bus_scan_fixed();
  
  	if (result)
  		acpi_device_unregister(acpi_root, ACPI_BUS_REMOVAL_NORMAL);
  	else
  		acpi_update_all_gpes();
  
  	return result;
  }
  