Fixed MTP to work with TWRP

drivers/acpi/acpica/nsxfeval.c

@@ -0,0 +1,996 @@
+/*******************************************************************************
+ *
+ * Module Name: nsxfeval - Public interfaces to the ACPI subsystem
+ *                         ACPI Object evaluation interfaces
+ *
+ ******************************************************************************/
+
+/*
+ * Copyright (C) 2000 - 2014, Intel Corp.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions, and the following disclaimer,
+ *    without modification.
+ * 2. Redistributions in binary form must reproduce at minimum a disclaimer
+ *    substantially similar to the "NO WARRANTY" disclaimer below
+ *    ("Disclaimer") and any redistribution must be conditioned upon
+ *    including a substantially similar Disclaimer requirement for further
+ *    binary redistribution.
+ * 3. Neither the names of the above-listed copyright holders nor the names
+ *    of any contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * NO WARRANTY
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGES.
+ */
+
+#define EXPORT_ACPI_INTERFACES
+
+#include <acpi/acpi.h>
+#include "accommon.h"
+#include "acnamesp.h"
+#include "acinterp.h"
+
+#define _COMPONENT          ACPI_NAMESPACE
+ACPI_MODULE_NAME("nsxfeval")
+
+/* Local prototypes */
+static void acpi_ns_resolve_references(struct acpi_evaluate_info *info);
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_evaluate_object_typed
+ *
+ * PARAMETERS:  handle              - Object handle (optional)
+ *              pathname            - Object pathname (optional)
+ *              external_params     - List of parameters to pass to method,
+ *                                    terminated by NULL. May be NULL
+ *                                    if no parameters are being passed.
+ *              return_buffer       - Where to put method's return value (if
+ *                                    any). If NULL, no value is returned.
+ *              return_type         - Expected type of return object
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Find and evaluate the given object, passing the given
+ *              parameters if necessary. One of "Handle" or "Pathname" must
+ *              be valid (non-null)
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_evaluate_object_typed(acpi_handle handle,
+			   acpi_string pathname,
+			   struct acpi_object_list *external_params,
+			   struct acpi_buffer *return_buffer,
+			   acpi_object_type return_type)
+{
+	acpi_status status;
+	u8 free_buffer_on_error = FALSE;
+
+	ACPI_FUNCTION_TRACE(acpi_evaluate_object_typed);
+
+	/* Return buffer must be valid */
+
+	if (!return_buffer) {
+		return_ACPI_STATUS(AE_BAD_PARAMETER);
+	}
+
+	if (return_buffer->length == ACPI_ALLOCATE_BUFFER) {
+		free_buffer_on_error = TRUE;
+	}
+
+	/* Evaluate the object */
+
+	status = acpi_evaluate_object(handle, pathname,
+				      external_params, return_buffer);
+	if (ACPI_FAILURE(status)) {
+		return_ACPI_STATUS(status);
+	}
+
+	/* Type ANY means "don't care" */
+
+	if (return_type == ACPI_TYPE_ANY) {
+		return_ACPI_STATUS(AE_OK);
+	}
+
+	if (return_buffer->length == 0) {
+
+		/* Error because caller specifically asked for a return value */
+
+		ACPI_ERROR((AE_INFO, "No return value"));
+		return_ACPI_STATUS(AE_NULL_OBJECT);
+	}
+
+	/* Examine the object type returned from evaluate_object */
+
+	if (((union acpi_object *)return_buffer->pointer)->type == return_type) {
+		return_ACPI_STATUS(AE_OK);
+	}
+
+	/* Return object type does not match requested type */
+
+	ACPI_ERROR((AE_INFO,
+		    "Incorrect return type [%s] requested [%s]",
+		    acpi_ut_get_type_name(((union acpi_object *)return_buffer->
+					   pointer)->type),
+		    acpi_ut_get_type_name(return_type)));
+
+	if (free_buffer_on_error) {
+		/*
+		 * Free a buffer created via ACPI_ALLOCATE_BUFFER.
+		 * Note: We use acpi_os_free here because acpi_os_allocate was used
+		 * to allocate the buffer. This purposefully bypasses the
+		 * (optionally enabled) allocation tracking mechanism since we
+		 * only want to track internal allocations.
+		 */
+		acpi_os_free(return_buffer->pointer);
+		return_buffer->pointer = NULL;
+	}
+
+	return_buffer->length = 0;
+	return_ACPI_STATUS(AE_TYPE);
+}
+
+ACPI_EXPORT_SYMBOL(acpi_evaluate_object_typed)
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_evaluate_object
+ *
+ * PARAMETERS:  handle              - Object handle (optional)
+ *              pathname            - Object pathname (optional)
+ *              external_params     - List of parameters to pass to method,
+ *                                    terminated by NULL. May be NULL
+ *                                    if no parameters are being passed.
+ *              return_buffer       - Where to put method's return value (if
+ *                                    any). If NULL, no value is returned.
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Find and evaluate the given object, passing the given
+ *              parameters if necessary. One of "Handle" or "Pathname" must
+ *              be valid (non-null)
+ *
+ ******************************************************************************/
+acpi_status
+acpi_evaluate_object(acpi_handle handle,
+		     acpi_string pathname,
+		     struct acpi_object_list *external_params,
+		     struct acpi_buffer *return_buffer)
+{
+	acpi_status status;
+	struct acpi_evaluate_info *info;
+	acpi_size buffer_space_needed;
+	u32 i;
+
+	ACPI_FUNCTION_TRACE(acpi_evaluate_object);
+
+	/* Allocate and initialize the evaluation information block */
+
+	info = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_evaluate_info));
+	if (!info) {
+		return_ACPI_STATUS(AE_NO_MEMORY);
+	}
+
+	/* Convert and validate the device handle */
+
+	info->prefix_node = acpi_ns_validate_handle(handle);
+	if (!info->prefix_node) {
+		status = AE_BAD_PARAMETER;
+		goto cleanup;
+	}
+
+	/*
+	 * Get the actual namespace node for the target object.
+	 * Handles these cases:
+	 *
+	 * 1) Null node, valid pathname from root (absolute path)
+	 * 2) Node and valid pathname (path relative to Node)
+	 * 3) Node, Null pathname
+	 */
+	if ((pathname) && (ACPI_IS_ROOT_PREFIX(pathname[0]))) {
+
+		/* The path is fully qualified, just evaluate by name */
+
+		info->prefix_node = NULL;
+	} else if (!handle) {
+		/*
+		 * A handle is optional iff a fully qualified pathname is specified.
+		 * Since we've already handled fully qualified names above, this is
+		 * an error.
+		 */
+		if (!pathname) {
+			ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+					  "Both Handle and Pathname are NULL"));
+		} else {
+			ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+					  "Null Handle with relative pathname [%s]",
+					  pathname));
+		}
+
+		status = AE_BAD_PARAMETER;
+		goto cleanup;
+	}
+
+	info->relative_pathname = pathname;
+
+	/*
+	 * Convert all external objects passed as arguments to the
+	 * internal version(s).
+	 */
+	if (external_params && external_params->count) {
+		info->param_count = (u16)external_params->count;
+
+		/* Warn on impossible argument count */
+
+		if (info->param_count > ACPI_METHOD_NUM_ARGS) {
+			ACPI_WARN_PREDEFINED((AE_INFO, pathname,
+					      ACPI_WARN_ALWAYS,
+					      "Excess arguments (%u) - using only %u",
+					      info->param_count,
+					      ACPI_METHOD_NUM_ARGS));
+
+			info->param_count = ACPI_METHOD_NUM_ARGS;
+		}
+
+		/*
+		 * Allocate a new parameter block for the internal objects
+		 * Add 1 to count to allow for null terminated internal list
+		 */
+		info->parameters = ACPI_ALLOCATE_ZEROED(((acpi_size) info->
+							 param_count +
+							 1) * sizeof(void *));
+		if (!info->parameters) {
+			status = AE_NO_MEMORY;
+			goto cleanup;
+		}
+
+		/* Convert each external object in the list to an internal object */
+
+		for (i = 0; i < info->param_count; i++) {
+			status =
+			    acpi_ut_copy_eobject_to_iobject(&external_params->
+							    pointer[i],
+							    &info->
+							    parameters[i]);
+			if (ACPI_FAILURE(status)) {
+				goto cleanup;
+			}
+		}
+
+		info->parameters[info->param_count] = NULL;
+	}
+
+#if 0
+
+	/*
+	 * Begin incoming argument count analysis. Check for too few args
+	 * and too many args.
+	 */
+
+	switch (acpi_ns_get_type(info->node)) {
+	case ACPI_TYPE_METHOD:
+
+		/* Check incoming argument count against the method definition */
+
+		if (info->obj_desc->method.param_count > info->param_count) {
+			ACPI_ERROR((AE_INFO,
+				    "Insufficient arguments (%u) - %u are required",
+				    info->param_count,
+				    info->obj_desc->method.param_count));
+
+			status = AE_MISSING_ARGUMENTS;
+			goto cleanup;
+		}
+
+		else if (info->obj_desc->method.param_count < info->param_count) {
+			ACPI_WARNING((AE_INFO,
+				      "Excess arguments (%u) - only %u are required",
+				      info->param_count,
+				      info->obj_desc->method.param_count));
+
+			/* Just pass the required number of arguments */
+
+			info->param_count = info->obj_desc->method.param_count;
+		}
+
+		/*
+		 * Any incoming external objects to be passed as arguments to the
+		 * method must be converted to internal objects
+		 */
+		if (info->param_count) {
+			/*
+			 * Allocate a new parameter block for the internal objects
+			 * Add 1 to count to allow for null terminated internal list
+			 */
+			info->parameters = ACPI_ALLOCATE_ZEROED(((acpi_size)
+								 info->
+								 param_count +
+								 1) *
+								sizeof(void *));
+			if (!info->parameters) {
+				status = AE_NO_MEMORY;
+				goto cleanup;
+			}
+
+			/* Convert each external object in the list to an internal object */
+
+			for (i = 0; i < info->param_count; i++) {
+				status =
+				    acpi_ut_copy_eobject_to_iobject
+				    (&external_params->pointer[i],
+				     &info->parameters[i]);
+				if (ACPI_FAILURE(status)) {
+					goto cleanup;
+				}
+			}
+
+			info->parameters[info->param_count] = NULL;
+		}
+		break;
+
+	default:
+
+		/* Warn if arguments passed to an object that is not a method */
+
+		if (info->param_count) {
+			ACPI_WARNING((AE_INFO,
+				      "%u arguments were passed to a non-method ACPI object",
+				      info->param_count));
+		}
+		break;
+	}
+
+#endif
+
+	/* Now we can evaluate the object */
+
+	status = acpi_ns_evaluate(info);
+
+	/*
+	 * If we are expecting a return value, and all went well above,
+	 * copy the return value to an external object.
+	 */
+	if (return_buffer) {
+		if (!info->return_object) {
+			return_buffer->length = 0;
+		} else {
+			if (ACPI_GET_DESCRIPTOR_TYPE(info->return_object) ==
+			    ACPI_DESC_TYPE_NAMED) {
+				/*
+				 * If we received a NS Node as a return object, this means that
+				 * the object we are evaluating has nothing interesting to
+				 * return (such as a mutex, etc.)  We return an error because
+				 * these types are essentially unsupported by this interface.
+				 * We don't check up front because this makes it easier to add
+				 * support for various types at a later date if necessary.
+				 */
+				status = AE_TYPE;
+				info->return_object = NULL;	/* No need to delete a NS Node */
+				return_buffer->length = 0;
+			}
+
+			if (ACPI_SUCCESS(status)) {
+
+				/* Dereference Index and ref_of references */
+
+				acpi_ns_resolve_references(info);
+
+				/* Get the size of the returned object */
+
+				status =
+				    acpi_ut_get_object_size(info->return_object,
+							    &buffer_space_needed);
+				if (ACPI_SUCCESS(status)) {
+
+					/* Validate/Allocate/Clear caller buffer */
+
+					status =
+					    acpi_ut_initialize_buffer
+					    (return_buffer,
+					     buffer_space_needed);
+					if (ACPI_FAILURE(status)) {
+						/*
+						 * Caller's buffer is too small or a new one can't
+						 * be allocated
+						 */
+						ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+								  "Needed buffer size %X, %s\n",
+								  (u32)
+								  buffer_space_needed,
+								  acpi_format_exception
+								  (status)));
+					} else {
+						/* We have enough space for the object, build it */
+
+						status =
+						    acpi_ut_copy_iobject_to_eobject
+						    (info->return_object,
+						     return_buffer);
+					}
+				}
+			}
+		}
+	}
+
+	if (info->return_object) {
+		/*
+		 * Delete the internal return object. NOTE: Interpreter must be
+		 * locked to avoid race condition.
+		 */
+		acpi_ex_enter_interpreter();
+
+		/* Remove one reference on the return object (should delete it) */
+
+		acpi_ut_remove_reference(info->return_object);
+		acpi_ex_exit_interpreter();
+	}
+
+cleanup:
+
+	/* Free the input parameter list (if we created one) */
+
+	if (info->parameters) {
+
+		/* Free the allocated parameter block */
+
+		acpi_ut_delete_internal_object_list(info->parameters);
+	}
+
+	ACPI_FREE(info);
+	return_ACPI_STATUS(status);
+}
+
+ACPI_EXPORT_SYMBOL(acpi_evaluate_object)
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ns_resolve_references
+ *
+ * PARAMETERS:  info                    - Evaluation info block
+ *
+ * RETURN:      Info->return_object is replaced with the dereferenced object
+ *
+ * DESCRIPTION: Dereference certain reference objects. Called before an
+ *              internal return object is converted to an external union acpi_object.
+ *
+ * Performs an automatic dereference of Index and ref_of reference objects.
+ * These reference objects are not supported by the union acpi_object, so this is a
+ * last resort effort to return something useful. Also, provides compatibility
+ * with other ACPI implementations.
+ *
+ * NOTE: does not handle references within returned package objects or nested
+ * references, but this support could be added later if found to be necessary.
+ *
+ ******************************************************************************/
+static void acpi_ns_resolve_references(struct acpi_evaluate_info *info)
+{
+	union acpi_operand_object *obj_desc = NULL;
+	struct acpi_namespace_node *node;
+
+	/* We are interested in reference objects only */
+
+	if ((info->return_object)->common.type != ACPI_TYPE_LOCAL_REFERENCE) {
+		return;
+	}
+
+	/*
+	 * Two types of references are supported - those created by Index and
+	 * ref_of operators. A name reference (AML_NAMEPATH_OP) can be converted
+	 * to an union acpi_object, so it is not dereferenced here. A ddb_handle
+	 * (AML_LOAD_OP) cannot be dereferenced, nor can it be converted to
+	 * an union acpi_object.
+	 */
+	switch (info->return_object->reference.class) {
+	case ACPI_REFCLASS_INDEX:
+
+		obj_desc = *(info->return_object->reference.where);
+		break;
+
+	case ACPI_REFCLASS_REFOF:
+
+		node = info->return_object->reference.object;
+		if (node) {
+			obj_desc = node->object;
+		}
+		break;
+
+	default:
+
+		return;
+	}
+
+	/* Replace the existing reference object */
+
+	if (obj_desc) {
+		acpi_ut_add_reference(obj_desc);
+		acpi_ut_remove_reference(info->return_object);
+		info->return_object = obj_desc;
+	}
+
+	return;
+}
+
+/*******************************************************************************
+ *
+ * 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
+ *              descending_callback - Called during tree descent
+ *                                    when an object of "Type" is found
+ *              ascending_callback  - Called during tree ascent
+ *                                    when an object of "Type" is found
+ *              context             - Passed to user function(s) above
+ *              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 callback function is called whenever an object that matches
+ *              the type parameter is found. If the callback 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 callback function(s) 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 descending_callback,
+		    acpi_walk_callback ascending_callback,
+		    void *context, void **return_value)
+{
+	acpi_status status;
+
+	ACPI_FUNCTION_TRACE(acpi_walk_namespace);
+
+	/* Parameter validation */
+
+	if ((type > ACPI_TYPE_LOCAL_MAX) ||
+	    (!max_depth) || (!descending_callback && !ascending_callback)) {
+		return_ACPI_STATUS(AE_BAD_PARAMETER);
+	}
+
+	/*
+	 * Need to acquire the namespace reader lock to prevent interference
+	 * with any concurrent table unloads (which causes the deletion of
+	 * namespace objects). We cannot allow the deletion of a namespace node
+	 * while the user function is using it. The exception to this are the
+	 * nodes created and deleted during control method execution -- these
+	 * nodes are marked as temporary nodes and are ignored by the namespace
+	 * walk. Thus, control methods can be executed while holding the
+	 * namespace deletion lock (and the user function can execute control
+	 * methods.)
+	 */
+	status = acpi_ut_acquire_read_lock(&acpi_gbl_namespace_rw_lock);
+	if (ACPI_FAILURE(status)) {
+		return_ACPI_STATUS(status);
+	}
+
+	/*
+	 * Lock the namespace around the walk. The namespace will be
+	 * unlocked/locked around each call to the user function - since the user
+	 * function must be allowed to make ACPICA calls itself (for example, it
+	 * will typically execute control methods during device enumeration.)
+	 */
+	status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
+	if (ACPI_FAILURE(status)) {
+		goto unlock_and_exit;
+	}
+
+	/* Now we can validate the starting node */
+
+	if (!acpi_ns_validate_handle(start_object)) {
+		status = AE_BAD_PARAMETER;
+		goto unlock_and_exit2;
+	}
+
+	status = acpi_ns_walk_namespace(type, start_object, max_depth,
+					ACPI_NS_WALK_UNLOCK,
+					descending_callback, ascending_callback,
+					context, return_value);
+
+unlock_and_exit2:
+	(void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
+
+unlock_and_exit:
+	(void)acpi_ut_release_read_lock(&acpi_gbl_namespace_rw_lock);
+	return_ACPI_STATUS(status);
+}
+
+ACPI_EXPORT_SYMBOL(acpi_walk_namespace)
+
+/*******************************************************************************
+ *
+ * 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)
+{
+	struct acpi_get_devices_info *info = context;
+	acpi_status status;
+	struct acpi_namespace_node *node;
+	u32 flags;
+	struct acpi_pnp_device_id *hid;
+	struct acpi_pnp_device_id_list *cid;
+	u32 i;
+	u8 found;
+	int no_match;
+
+	status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
+	if (ACPI_FAILURE(status)) {
+		return (status);
+	}
+
+	node = acpi_ns_validate_handle(obj_handle);
+	status = acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
+	if (ACPI_FAILURE(status)) {
+		return (status);
+	}
+
+	if (!node) {
+		return (AE_BAD_PARAMETER);
+	}
+
+	/*
+	 * First, filter based on the device HID and CID.
+	 *
+	 * 01/2010: For this case where a specific HID is requested, we don't
+	 * want to run _STA until we have an actual HID match. Thus, we will
+	 * not unnecessarily execute _STA on devices for which the caller
+	 * doesn't care about. Previously, _STA was executed unconditionally
+	 * on all devices found here.
+	 *
+	 * A side-effect of this change is that now we will continue to search
+	 * for a matching HID even under device trees where the parent device
+	 * would have returned a _STA that indicates it is not present or
+	 * not functioning (thus aborting the search on that branch).
+	 */
+	if (info->hid != NULL) {
+		status = acpi_ut_execute_HID(node, &hid);
+		if (status == AE_NOT_FOUND) {
+			return (AE_OK);
+		} else if (ACPI_FAILURE(status)) {
+			return (AE_CTRL_DEPTH);
+		}
+
+		no_match = ACPI_STRCMP(hid->string, info->hid);
+		ACPI_FREE(hid);
+
+		if (no_match) {
+			/*
+			 * HID does not match, attempt match within the
+			 * list of Compatible IDs (CIDs)
+			 */
+			status = acpi_ut_execute_CID(node, &cid);
+			if (status == AE_NOT_FOUND) {
+				return (AE_OK);
+			} else if (ACPI_FAILURE(status)) {
+				return (AE_CTRL_DEPTH);
+			}
+
+			/* Walk the CID list */
+
+			found = FALSE;
+			for (i = 0; i < cid->count; i++) {
+				if (ACPI_STRCMP(cid->ids[i].string, info->hid)
+				    == 0) {
+
+					/* Found a matching CID */
+
+					found = TRUE;
+					break;
+				}
+			}
+
+			ACPI_FREE(cid);
+			if (!found) {
+				return (AE_OK);
+			}
+		}
+	}
+
+	/* 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 & ACPI_STA_DEVICE_PRESENT) &&
+	    !(flags & ACPI_STA_DEVICE_FUNCTIONING)) {
+		/*
+		 * Don't examine the children of the device only when the
+		 * device is neither present nor functional. See ACPI spec,
+		 * description of _STA for more information.
+		 */
+		return (AE_CTRL_DEPTH);
+	}
+
+	/* We have a valid device, invoke the user function */
+
+	status = info->user_function(obj_handle, nesting_level, info->context,
+				     return_value);
+	return (status);
+}
+
+/*******************************************************************************
+ *
+ * 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 of type
+ *              Device 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_ns_get_device_callback.
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_get_devices(const char *HID,
+		 acpi_walk_callback user_function,
+		 void *context, void **return_value)
+{
+	acpi_status status;
+	struct acpi_get_devices_info info;
+
+	ACPI_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.hid = HID;
+	info.context = context;
+	info.user_function = user_function;
+
+	/*
+	 * 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.
+	 */
+	status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
+	if (ACPI_FAILURE(status)) {
+		return_ACPI_STATUS(status);
+	}
+
+	status = acpi_ns_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
+					ACPI_UINT32_MAX, ACPI_NS_WALK_UNLOCK,
+					acpi_ns_get_device_callback, NULL,
+					&info, return_value);
+
+	(void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
+	return_ACPI_STATUS(status);
+}
+
+ACPI_EXPORT_SYMBOL(acpi_get_devices)
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_attach_data
+ *
+ * PARAMETERS:  obj_handle          - Namespace node
+ *              handler             - Handler for this attachment
+ *              data                - Pointer to data to be attached
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Attach arbitrary data and handler to a namespace node.
+ *
+ ******************************************************************************/
+acpi_status
+acpi_attach_data(acpi_handle obj_handle,
+		 acpi_object_handler handler, void *data)
+{
+	struct acpi_namespace_node *node;
+	acpi_status status;
+
+	/* Parameter validation */
+
+	if (!obj_handle || !handler || !data) {
+		return (AE_BAD_PARAMETER);
+	}
+
+	status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
+	if (ACPI_FAILURE(status)) {
+		return (status);
+	}
+
+	/* Convert and validate the handle */
+
+	node = acpi_ns_validate_handle(obj_handle);
+	if (!node) {
+		status = AE_BAD_PARAMETER;
+		goto unlock_and_exit;
+	}
+
+	status = acpi_ns_attach_data(node, handler, data);
+
+unlock_and_exit:
+	(void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
+	return (status);
+}
+
+ACPI_EXPORT_SYMBOL(acpi_attach_data)
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_detach_data
+ *
+ * PARAMETERS:  obj_handle          - Namespace node handle
+ *              handler             - Handler used in call to acpi_attach_data
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Remove data that was previously attached to a node.
+ *
+ ******************************************************************************/
+acpi_status
+acpi_detach_data(acpi_handle obj_handle, acpi_object_handler handler)
+{
+	struct acpi_namespace_node *node;
+	acpi_status status;
+
+	/* Parameter validation */
+
+	if (!obj_handle || !handler) {
+		return (AE_BAD_PARAMETER);
+	}
+
+	status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
+	if (ACPI_FAILURE(status)) {
+		return (status);
+	}
+
+	/* Convert and validate the handle */
+
+	node = acpi_ns_validate_handle(obj_handle);
+	if (!node) {
+		status = AE_BAD_PARAMETER;
+		goto unlock_and_exit;
+	}
+
+	status = acpi_ns_detach_data(node, handler);
+
+unlock_and_exit:
+	(void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
+	return (status);
+}
+
+ACPI_EXPORT_SYMBOL(acpi_detach_data)
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_get_data_full
+ *
+ * PARAMETERS:  obj_handle          - Namespace node
+ *              handler             - Handler used in call to attach_data
+ *              data                - Where the data is returned
+ *              callback            - function to execute before returning
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Retrieve data that was previously attached to a namespace node
+ *              and execute a callback before returning.
+ *
+ ******************************************************************************/
+acpi_status
+acpi_get_data_full(acpi_handle obj_handle, acpi_object_handler handler,
+		   void **data, void (*callback)(void *))
+{
+	struct acpi_namespace_node *node;
+	acpi_status status;
+
+	/* Parameter validation */
+
+	if (!obj_handle || !handler || !data) {
+		return (AE_BAD_PARAMETER);
+	}
+
+	status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
+	if (ACPI_FAILURE(status)) {
+		return (status);
+	}
+
+	/* Convert and validate the handle */
+
+	node = acpi_ns_validate_handle(obj_handle);
+	if (!node) {
+		status = AE_BAD_PARAMETER;
+		goto unlock_and_exit;
+	}
+
+	status = acpi_ns_get_attached_data(node, handler, data);
+	if (ACPI_SUCCESS(status) && callback) {
+		callback(*data);
+	}
+
+unlock_and_exit:
+	(void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
+	return (status);
+}
+
+ACPI_EXPORT_SYMBOL(acpi_get_data_full)
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_get_data
+ *
+ * PARAMETERS:  obj_handle          - Namespace node
+ *              handler             - Handler used in call to attach_data
+ *              data                - Where the data is returned
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Retrieve data that was previously attached to a namespace node.
+ *
+ ******************************************************************************/
+acpi_status
+acpi_get_data(acpi_handle obj_handle, acpi_object_handler handler, void **data)
+{
+	return acpi_get_data_full(obj_handle, handler, data, NULL);
+}
+
+ACPI_EXPORT_SYMBOL(acpi_get_data)