nsxfobj.c

这个linux源代码是很全面的~基本完整了~使用c编译的~由于时间问题我没有亲自测试~但就算用来做参考资料也是非常好的

/*******************************************************************************
 *
 * FUNCTION:    Acpi_get_type
 *
 * PARAMETERS:  Handle          - Handle of object whose type is desired
 *              *Ret_type       - Where the type will be placed
 *
 * RETURN:      Status
 *
 * DESCRIPTION: This routine returns the type associatd with a particular handle
 *
 ******************************************************************************/

acpi_status
acpi_get_type (
	acpi_handle             handle,
	acpi_object_type        *ret_type)
{
	acpi_namespace_node     *node;


	/* Parameter Validation */

	if (!ret_type) {
		return (AE_BAD_PARAMETER);
	}

	/*
	 * Special case for the predefined Root Node
	 * (return type ANY)
	 */
	if (handle == ACPI_ROOT_OBJECT) {
		*ret_type = ACPI_TYPE_ANY;
		return (AE_OK);
	}

	acpi_ut_acquire_mutex (ACPI_MTX_NAMESPACE);

	/* Convert and validate the handle */

	node = acpi_ns_map_handle_to_node (handle);
	if (!node) {
		acpi_ut_release_mutex (ACPI_MTX_NAMESPACE);
		return (AE_BAD_PARAMETER);
	}

	*ret_type = node->type;


	acpi_ut_release_mutex (ACPI_MTX_NAMESPACE);
	return (AE_OK);
}


/*******************************************************************************
 *
 * FUNCTION:    Acpi_get_parent
 *
 * PARAMETERS:  Handle          - Handle of object whose parent is desired
 *              Ret_handle      - Where the parent handle will be placed
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Returns a handle to the parent of the object represented by
 *              Handle.
 *
 ******************************************************************************/

acpi_status
acpi_get_parent (
	acpi_handle             handle,
	acpi_handle             *ret_handle)
{
	acpi_namespace_node     *node;
	acpi_status             status = AE_OK;


	if (!ret_handle) {
		return (AE_BAD_PARAMETER);
	}

	/* Special case for the predefined Root Node (no parent) */

	if (handle == ACPI_ROOT_OBJECT) {
		return (AE_NULL_ENTRY);
	}


	acpi_ut_acquire_mutex (ACPI_MTX_NAMESPACE);

	/* Convert and validate the handle */

	node = acpi_ns_map_handle_to_node (handle);
	if (!node) {
		status = AE_BAD_PARAMETER;
		goto unlock_and_exit;
	}


	/* Get the parent entry */

	*ret_handle =
		acpi_ns_convert_entry_to_handle (acpi_ns_get_parent_object (node));

	/* Return exeption if parent is null */

	if (!acpi_ns_get_parent_object (node)) {
		status = AE_NULL_ENTRY;
	}


unlock_and_exit:

	acpi_ut_release_mutex (ACPI_MTX_NAMESPACE);
	return (status);
}


/*******************************************************************************
 *
 * FUNCTION:    Acpi_walk_namespace
 *
 * PARAMETERS:  Type                - acpi_object_type to search for
 *              Start_object        - Handle in namespace where search begins
 *              Max_depth           - Depth to which search is to reach
 *              User_function       - Called when an object of "Type" is found
 *              Context             - Passed to user function
 *              Return_value        - Location where return value of
 *                                    User_function is put if terminated early
 *
 * RETURNS      Return value from the User_function if terminated early.
 *              Otherwise, returns NULL.
 *
 * DESCRIPTION: Performs a modified depth-first walk of the namespace tree,
 *              starting (and ending) at the object specified by Start_handle.
 *              The User_function is called whenever an object that matches
 *              the type parameter is found.  If the user function returns
 *              a non-zero value, the search is terminated immediately and this
 *              value is returned to the caller.
 *
 *              The point of this procedure is to provide a generic namespace
 *              walk routine that can be called from multiple places to
 *              provide multiple services;  the User Function can be tailored
 *              to each task, whether it is a print function, a compare
 *              function, etc.
 *
 ******************************************************************************/

acpi_status
acpi_walk_namespace (
	acpi_object_type        type,
	acpi_handle             start_object,
	u32                     max_depth,
	acpi_walk_callback      user_function,
	void                    *context,
	void                    **return_value)
{
	acpi_status             status;


	FUNCTION_TRACE ("Acpi_walk_namespace");


	/* Parameter validation */

	if ((type > ACPI_TYPE_MAX)  ||
		(!max_depth)            ||
		(!user_function)) {
		return_ACPI_STATUS (AE_BAD_PARAMETER);
	}

	/*
	 * Lock the namespace around the walk.
	 * The namespace will be unlocked/locked around each call
	 * to the user function - since this function
	 * must be allowed to make Acpi calls itself.
	 */
	acpi_ut_acquire_mutex (ACPI_MTX_NAMESPACE);
	status = acpi_ns_walk_namespace ((acpi_object_type8) type, start_object,
			  max_depth, NS_WALK_UNLOCK, user_function, context,
			  return_value);

	acpi_ut_release_mutex (ACPI_MTX_NAMESPACE);

	return_ACPI_STATUS (status);
}


/*******************************************************************************
 *
 * FUNCTION:    Acpi_ns_get_device_callback
 *
 * PARAMETERS:  Callback from Acpi_get_device
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Takes callbacks from Walk_namespace and filters out all non-
 *              present devices, or if they specified a HID, it filters based
 *              on that.
 *
 ******************************************************************************/

static acpi_status
acpi_ns_get_device_callback (
	acpi_handle             obj_handle,
	u32                     nesting_level,
	void                    *context,
	void                    **return_value)
{
	acpi_status             status;
	acpi_namespace_node     *node;
	u32                     flags;
	acpi_device_id          device_id;
	acpi_get_devices_info   *info;


	info = context;

	acpi_ut_acquire_mutex (ACPI_MTX_NAMESPACE);
	node = acpi_ns_map_handle_to_node (obj_handle);
	acpi_ut_release_mutex (ACPI_MTX_NAMESPACE);

	if (!node) {
		return (AE_BAD_PARAMETER);
	}

	/*
	 * Run _STA to determine if device is present
	 */
	status = acpi_ut_execute_STA (node, &flags);
	if (ACPI_FAILURE (status)) {
		return (AE_CTRL_DEPTH);
	}

	if (!(flags & 0x01)) {
		/* don't return at the device or children of the device if not there */
		return (AE_CTRL_DEPTH);
	}

	/*
	 * Filter based on device HID
	 */
	if (info->hid != NULL) {
		status = acpi_ut_execute_HID (node, &device_id);
		if (status == AE_NOT_FOUND) {
			return (AE_OK);
		}

		else if (ACPI_FAILURE (status)) {
			return (AE_CTRL_DEPTH);
		}

		if (STRNCMP (device_id.buffer, info->hid, sizeof (device_id.buffer)) != 0) {
			return (AE_OK);
		}
	}

	info->user_function (obj_handle, nesting_level, info->context, return_value);
	return (AE_OK);
}


/*******************************************************************************
 *
 * FUNCTION:    Acpi_get_devices
 *
 * PARAMETERS:  HID                 - HID to search for. Can be NULL.
 *              User_function       - Called when a matching object is found
 *              Context             - Passed to user function
 *              Return_value        - Location where return value of
 *                                    User_function is put if terminated early
 *
 * RETURNS      Return value from the User_function if terminated early.
 *              Otherwise, returns NULL.
 *
 * DESCRIPTION: Performs a modified depth-first walk of the namespace tree,
 *              starting (and ending) at the object specified by Start_handle.
 *              The User_function is called whenever an object that matches
 *              the type parameter is found.  If the user function returns
 *              a non-zero value, the search is terminated immediately and this
 *              value is returned to the caller.
 *
 *              This is a wrapper for Walk_namespace, but the callback performs
 *              additional filtering. Please see Acpi_get_device_callback.
 *
 ******************************************************************************/

acpi_status
acpi_get_devices (
	NATIVE_CHAR             *HID,
	acpi_walk_callback      user_function,
	void                    *context,
	void                    **return_value)
{
	acpi_status             status;
	acpi_get_devices_info   info;


	FUNCTION_TRACE ("Acpi_get_devices");


	/* Parameter validation */

	if (!user_function) {
		return_ACPI_STATUS (AE_BAD_PARAMETER);
	}

	/*
	 * We're going to call their callback from OUR callback, so we need
	 * to know what it is, and their context parameter.
	 */
	info.context      = context;
	info.user_function = user_function;
	info.hid          = HID;

	/*
	 * Lock the namespace around the walk.
	 * The namespace will be unlocked/locked around each call
	 * to the user function - since this function
	 * must be allowed to make Acpi calls itself.
	 */
	acpi_ut_acquire_mutex (ACPI_MTX_NAMESPACE);
	status = acpi_ns_walk_namespace (ACPI_TYPE_DEVICE,
			   ACPI_ROOT_OBJECT, ACPI_UINT32_MAX,
			   NS_WALK_UNLOCK,
			   acpi_ns_get_device_callback, &info,
			   return_value);

	acpi_ut_release_mutex (ACPI_MTX_NAMESPACE);

	return_ACPI_STATUS (status);
}