Initial import

1 files changed, 795 insertions, 0 deletions

diff --git a/drivers/acpi/acpica/evregion.c b/drivers/acpi/acpica/evregion.c
new file mode 100644
index 000000000..2ba28a63f
--- /dev/null
+++ b/drivers/acpi/acpica/evregion.c
@@ -0,0 +1,795 @@
+/******************************************************************************
+ *
+ * Module Name: evregion - Operation Region support
+ *
+ *****************************************************************************/
+
+/*
+ * Copyright (C) 2000 - 2015, 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.
+ */
+
+#include <acpi/acpi.h>
+#include "accommon.h"
+#include "acevents.h"
+#include "acnamesp.h"
+#include "acinterp.h"
+
+#define _COMPONENT          ACPI_EVENTS
+ACPI_MODULE_NAME("evregion")
+
+extern u8 acpi_gbl_default_address_spaces[];
+
+/* Local prototypes */
+
+static void
+acpi_ev_orphan_ec_reg_method(struct acpi_namespace_node *ec_device_node);
+
+static acpi_status
+acpi_ev_reg_run(acpi_handle obj_handle,
+		u32 level, void *context, void **return_value);
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ev_initialize_op_regions
+ *
+ * PARAMETERS:  None
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Execute _REG methods for all Operation Regions that have
+ *              an installed default region handler.
+ *
+ ******************************************************************************/
+
+acpi_status acpi_ev_initialize_op_regions(void)
+{
+	acpi_status status;
+	u32 i;
+
+	ACPI_FUNCTION_TRACE(ev_initialize_op_regions);
+
+	status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
+	if (ACPI_FAILURE(status)) {
+		return_ACPI_STATUS(status);
+	}
+
+	/* Run the _REG methods for op_regions in each default address space */
+
+	for (i = 0; i < ACPI_NUM_DEFAULT_SPACES; i++) {
+		/*
+		 * Make sure the installed handler is the DEFAULT handler. If not the
+		 * default, the _REG methods will have already been run (when the
+		 * handler was installed)
+		 */
+		if (acpi_ev_has_default_handler(acpi_gbl_root_node,
+						acpi_gbl_default_address_spaces
+						[i])) {
+			status =
+			    acpi_ev_execute_reg_methods(acpi_gbl_root_node,
+							acpi_gbl_default_address_spaces
+							[i]);
+		}
+	}
+
+	acpi_gbl_reg_methods_executed = TRUE;
+
+	(void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
+	return_ACPI_STATUS(status);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ev_address_space_dispatch
+ *
+ * PARAMETERS:  region_obj          - Internal region object
+ *              field_obj           - Corresponding field. Can be NULL.
+ *              function            - Read or Write operation
+ *              region_offset       - Where in the region to read or write
+ *              bit_width           - Field width in bits (8, 16, 32, or 64)
+ *              value               - Pointer to in or out value, must be
+ *                                    a full 64-bit integer
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Dispatch an address space or operation region access to
+ *              a previously installed handler.
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_ev_address_space_dispatch(union acpi_operand_object *region_obj,
+			       union acpi_operand_object *field_obj,
+			       u32 function,
+			       u32 region_offset, u32 bit_width, u64 *value)
+{
+	acpi_status status;
+	acpi_adr_space_handler handler;
+	acpi_adr_space_setup region_setup;
+	union acpi_operand_object *handler_desc;
+	union acpi_operand_object *region_obj2;
+	void *region_context = NULL;
+	struct acpi_connection_info *context;
+	acpi_physical_address address;
+
+	ACPI_FUNCTION_TRACE(ev_address_space_dispatch);
+
+	region_obj2 = acpi_ns_get_secondary_object(region_obj);
+	if (!region_obj2) {
+		return_ACPI_STATUS(AE_NOT_EXIST);
+	}
+
+	/* Ensure that there is a handler associated with this region */
+
+	handler_desc = region_obj->region.handler;
+	if (!handler_desc) {
+		ACPI_ERROR((AE_INFO,
+			    "No handler for Region [%4.4s] (%p) [%s]",
+			    acpi_ut_get_node_name(region_obj->region.node),
+			    region_obj,
+			    acpi_ut_get_region_name(region_obj->region.
+						    space_id)));
+
+		return_ACPI_STATUS(AE_NOT_EXIST);
+	}
+
+	context = handler_desc->address_space.context;
+
+	/*
+	 * It may be the case that the region has never been initialized.
+	 * Some types of regions require special init code
+	 */
+	if (!(region_obj->region.flags & AOPOBJ_SETUP_COMPLETE)) {
+
+		/* This region has not been initialized yet, do it */
+
+		region_setup = handler_desc->address_space.setup;
+		if (!region_setup) {
+
+			/* No initialization routine, exit with error */
+
+			ACPI_ERROR((AE_INFO,
+				    "No init routine for region(%p) [%s]",
+				    region_obj,
+				    acpi_ut_get_region_name(region_obj->region.
+							    space_id)));
+			return_ACPI_STATUS(AE_NOT_EXIST);
+		}
+
+		/*
+		 * We must exit the interpreter because the region setup will
+		 * potentially execute control methods (for example, the _REG method
+		 * for this region)
+		 */
+		acpi_ex_exit_interpreter();
+
+		status = region_setup(region_obj, ACPI_REGION_ACTIVATE,
+				      context, &region_context);
+
+		/* Re-enter the interpreter */
+
+		acpi_ex_enter_interpreter();
+
+		/* Check for failure of the Region Setup */
+
+		if (ACPI_FAILURE(status)) {
+			ACPI_EXCEPTION((AE_INFO, status,
+					"During region initialization: [%s]",
+					acpi_ut_get_region_name(region_obj->
+								region.
+								space_id)));
+			return_ACPI_STATUS(status);
+		}
+
+		/* Region initialization may have been completed by region_setup */
+
+		if (!(region_obj->region.flags & AOPOBJ_SETUP_COMPLETE)) {
+			region_obj->region.flags |= AOPOBJ_SETUP_COMPLETE;
+
+			/*
+			 * Save the returned context for use in all accesses to
+			 * the handler for this particular region
+			 */
+			if (!(region_obj2->extra.region_context)) {
+				region_obj2->extra.region_context =
+				    region_context;
+			}
+		}
+	}
+
+	/* We have everything we need, we can invoke the address space handler */
+
+	handler = handler_desc->address_space.handler;
+	address = (region_obj->region.address + region_offset);
+
+	/*
+	 * Special handling for generic_serial_bus and general_purpose_io:
+	 * There are three extra parameters that must be passed to the
+	 * handler via the context:
+	 *   1) Connection buffer, a resource template from Connection() op
+	 *   2) Length of the above buffer
+	 *   3) Actual access length from the access_as() op
+	 *
+	 * In addition, for general_purpose_io, the Address and bit_width fields
+	 * are defined as follows:
+	 *   1) Address is the pin number index of the field (bit offset from
+	 *      the previous Connection)
+	 *   2) bit_width is the actual bit length of the field (number of pins)
+	 */
+	if ((region_obj->region.space_id == ACPI_ADR_SPACE_GSBUS) &&
+	    context && field_obj) {
+
+		/* Get the Connection (resource_template) buffer */
+
+		context->connection = field_obj->field.resource_buffer;
+		context->length = field_obj->field.resource_length;
+		context->access_length = field_obj->field.access_length;
+	}
+	if ((region_obj->region.space_id == ACPI_ADR_SPACE_GPIO) &&
+	    context && field_obj) {
+
+		/* Get the Connection (resource_template) buffer */
+
+		context->connection = field_obj->field.resource_buffer;
+		context->length = field_obj->field.resource_length;
+		context->access_length = field_obj->field.access_length;
+		address = field_obj->field.pin_number_index;
+		bit_width = field_obj->field.bit_length;
+	}
+
+	ACPI_DEBUG_PRINT((ACPI_DB_OPREGION,
+			  "Handler %p (@%p) Address %8.8X%8.8X [%s]\n",
+			  &region_obj->region.handler->address_space, handler,
+			  ACPI_FORMAT_UINT64(address),
+			  acpi_ut_get_region_name(region_obj->region.
+						  space_id)));
+
+	if (!(handler_desc->address_space.handler_flags &
+	      ACPI_ADDR_HANDLER_DEFAULT_INSTALLED)) {
+		/*
+		 * For handlers other than the default (supplied) handlers, we must
+		 * exit the interpreter because the handler *might* block -- we don't
+		 * know what it will do, so we can't hold the lock on the intepreter.
+		 */
+		acpi_ex_exit_interpreter();
+	}
+
+	/* Call the handler */
+
+	status = handler(function, address, bit_width, value, context,
+			 region_obj2->extra.region_context);
+
+	if (ACPI_FAILURE(status)) {
+		ACPI_EXCEPTION((AE_INFO, status, "Returned by Handler for [%s]",
+				acpi_ut_get_region_name(region_obj->region.
+							space_id)));
+	}
+
+	if (!(handler_desc->address_space.handler_flags &
+	      ACPI_ADDR_HANDLER_DEFAULT_INSTALLED)) {
+		/*
+		 * We just returned from a non-default handler, we must re-enter the
+		 * interpreter
+		 */
+		acpi_ex_enter_interpreter();
+	}
+
+	return_ACPI_STATUS(status);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ev_detach_region
+ *
+ * PARAMETERS:  region_obj          - Region Object
+ *              acpi_ns_is_locked   - Namespace Region Already Locked?
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Break the association between the handler and the region
+ *              this is a two way association.
+ *
+ ******************************************************************************/
+
+void
+acpi_ev_detach_region(union acpi_operand_object *region_obj,
+		      u8 acpi_ns_is_locked)
+{
+	union acpi_operand_object *handler_obj;
+	union acpi_operand_object *obj_desc;
+	union acpi_operand_object *start_desc;
+	union acpi_operand_object **last_obj_ptr;
+	acpi_adr_space_setup region_setup;
+	void **region_context;
+	union acpi_operand_object *region_obj2;
+	acpi_status status;
+
+	ACPI_FUNCTION_TRACE(ev_detach_region);
+
+	region_obj2 = acpi_ns_get_secondary_object(region_obj);
+	if (!region_obj2) {
+		return_VOID;
+	}
+	region_context = &region_obj2->extra.region_context;
+
+	/* Get the address handler from the region object */
+
+	handler_obj = region_obj->region.handler;
+	if (!handler_obj) {
+
+		/* This region has no handler, all done */
+
+		return_VOID;
+	}
+
+	/* Find this region in the handler's list */
+
+	obj_desc = handler_obj->address_space.region_list;
+	start_desc = obj_desc;
+	last_obj_ptr = &handler_obj->address_space.region_list;
+
+	while (obj_desc) {
+
+		/* Is this the correct Region? */
+
+		if (obj_desc == region_obj) {
+			ACPI_DEBUG_PRINT((ACPI_DB_OPREGION,
+					  "Removing Region %p from address handler %p\n",
+					  region_obj, handler_obj));
+
+			/* This is it, remove it from the handler's list */
+
+			*last_obj_ptr = obj_desc->region.next;
+			obj_desc->region.next = NULL;	/* Must clear field */
+
+			if (acpi_ns_is_locked) {
+				status =
+				    acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
+				if (ACPI_FAILURE(status)) {
+					return_VOID;
+				}
+			}
+
+			/* Now stop region accesses by executing the _REG method */
+
+			status =
+			    acpi_ev_execute_reg_method(region_obj,
+						       ACPI_REG_DISCONNECT);
+			if (ACPI_FAILURE(status)) {
+				ACPI_EXCEPTION((AE_INFO, status,
+						"from region _REG, [%s]",
+						acpi_ut_get_region_name
+						(region_obj->region.space_id)));
+			}
+
+			if (acpi_ns_is_locked) {
+				status =
+				    acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
+				if (ACPI_FAILURE(status)) {
+					return_VOID;
+				}
+			}
+
+			/*
+			 * If the region has been activated, call the setup handler with
+			 * the deactivate notification
+			 */
+			if (region_obj->region.flags & AOPOBJ_SETUP_COMPLETE) {
+				region_setup = handler_obj->address_space.setup;
+				status =
+				    region_setup(region_obj,
+						 ACPI_REGION_DEACTIVATE,
+						 handler_obj->address_space.
+						 context, region_context);
+
+				/*
+				 * region_context should have been released by the deactivate
+				 * operation. We don't need access to it anymore here.
+				 */
+				if (region_context) {
+					*region_context = NULL;
+				}
+
+				/* Init routine may fail, Just ignore errors */
+
+				if (ACPI_FAILURE(status)) {
+					ACPI_EXCEPTION((AE_INFO, status,
+							"from region handler - deactivate, [%s]",
+							acpi_ut_get_region_name
+							(region_obj->region.
+							 space_id)));
+				}
+
+				region_obj->region.flags &=
+				    ~(AOPOBJ_SETUP_COMPLETE);
+			}
+
+			/*
+			 * Remove handler reference in the region
+			 *
+			 * NOTE: this doesn't mean that the region goes away, the region
+			 * is just inaccessible as indicated to the _REG method
+			 *
+			 * If the region is on the handler's list, this must be the
+			 * region's handler
+			 */
+			region_obj->region.handler = NULL;
+			acpi_ut_remove_reference(handler_obj);
+
+			return_VOID;
+		}
+
+		/* Walk the linked list of handlers */
+
+		last_obj_ptr = &obj_desc->region.next;
+		obj_desc = obj_desc->region.next;
+
+		/* Prevent infinite loop if list is corrupted */
+
+		if (obj_desc == start_desc) {
+			ACPI_ERROR((AE_INFO,
+				    "Circular handler list in region object %p",
+				    region_obj));
+			return_VOID;
+		}
+	}
+
+	/* If we get here, the region was not in the handler's region list */
+
+	ACPI_DEBUG_PRINT((ACPI_DB_OPREGION,
+			  "Cannot remove region %p from address handler %p\n",
+			  region_obj, handler_obj));
+
+	return_VOID;
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ev_attach_region
+ *
+ * PARAMETERS:  handler_obj         - Handler Object
+ *              region_obj          - Region Object
+ *              acpi_ns_is_locked   - Namespace Region Already Locked?
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Create the association between the handler and the region
+ *              this is a two way association.
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_ev_attach_region(union acpi_operand_object *handler_obj,
+		      union acpi_operand_object *region_obj,
+		      u8 acpi_ns_is_locked)
+{
+
+	ACPI_FUNCTION_TRACE(ev_attach_region);
+
+	ACPI_DEBUG_PRINT((ACPI_DB_OPREGION,
+			  "Adding Region [%4.4s] %p to address handler %p [%s]\n",
+			  acpi_ut_get_node_name(region_obj->region.node),
+			  region_obj, handler_obj,
+			  acpi_ut_get_region_name(region_obj->region.
+						  space_id)));
+
+	/* Link this region to the front of the handler's list */
+
+	region_obj->region.next = handler_obj->address_space.region_list;
+	handler_obj->address_space.region_list = region_obj;
+
+	/* Install the region's handler */
+
+	if (region_obj->region.handler) {
+		return_ACPI_STATUS(AE_ALREADY_EXISTS);
+	}
+
+	region_obj->region.handler = handler_obj;
+	acpi_ut_add_reference(handler_obj);
+
+	return_ACPI_STATUS(AE_OK);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ev_execute_reg_method
+ *
+ * PARAMETERS:  region_obj          - Region object
+ *              function            - Passed to _REG: On (1) or Off (0)
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Execute _REG method for a region
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_ev_execute_reg_method(union acpi_operand_object *region_obj, u32 function)
+{
+	struct acpi_evaluate_info *info;
+	union acpi_operand_object *args[3];
+	union acpi_operand_object *region_obj2;
+	acpi_status status;
+
+	ACPI_FUNCTION_TRACE(ev_execute_reg_method);
+
+	region_obj2 = acpi_ns_get_secondary_object(region_obj);
+	if (!region_obj2) {
+		return_ACPI_STATUS(AE_NOT_EXIST);
+	}
+
+	if (region_obj2->extra.method_REG == NULL) {
+		return_ACPI_STATUS(AE_OK);
+	}
+
+	/* Allocate and initialize the evaluation information block */
+
+	info = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_evaluate_info));
+	if (!info) {
+		return_ACPI_STATUS(AE_NO_MEMORY);
+	}
+
+	info->prefix_node = region_obj2->extra.method_REG;
+	info->relative_pathname = NULL;
+	info->parameters = args;
+	info->flags = ACPI_IGNORE_RETURN_VALUE;
+
+	/*
+	 * The _REG method has two arguments:
+	 *
+	 * arg0 - Integer:
+	 *  Operation region space ID Same value as region_obj->Region.space_id
+	 *
+	 * arg1 - Integer:
+	 *  connection status 1 for connecting the handler, 0 for disconnecting
+	 *  the handler (Passed as a parameter)
+	 */
+	args[0] =
+	    acpi_ut_create_integer_object((u64)region_obj->region.space_id);
+	if (!args[0]) {
+		status = AE_NO_MEMORY;
+		goto cleanup1;
+	}
+
+	args[1] = acpi_ut_create_integer_object((u64)function);
+	if (!args[1]) {
+		status = AE_NO_MEMORY;
+		goto cleanup2;
+	}
+
+	args[2] = NULL;		/* Terminate list */
+
+	/* Execute the method, no return value */
+
+	ACPI_DEBUG_EXEC(acpi_ut_display_init_pathname
+			(ACPI_TYPE_METHOD, info->prefix_node, NULL));
+
+	status = acpi_ns_evaluate(info);
+	acpi_ut_remove_reference(args[1]);
+
+cleanup2:
+	acpi_ut_remove_reference(args[0]);
+
+cleanup1:
+	ACPI_FREE(info);
+	return_ACPI_STATUS(status);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ev_execute_reg_methods
+ *
+ * PARAMETERS:  node            - Namespace node for the device
+ *              space_id        - The address space ID
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Run all _REG methods for the input Space ID;
+ *              Note: assumes namespace is locked, or system init time.
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_ev_execute_reg_methods(struct acpi_namespace_node *node,
+			    acpi_adr_space_type space_id)
+{
+	acpi_status status;
+
+	ACPI_FUNCTION_TRACE(ev_execute_reg_methods);
+
+	/*
+	 * Run all _REG methods for all Operation Regions for this space ID. This
+	 * is a separate walk in order to handle any interdependencies between
+	 * regions and _REG methods. (i.e. handlers must be installed for all
+	 * regions of this Space ID before we can run any _REG methods)
+	 */
+	status = acpi_ns_walk_namespace(ACPI_TYPE_ANY, node, ACPI_UINT32_MAX,
+					ACPI_NS_WALK_UNLOCK, acpi_ev_reg_run,
+					NULL, &space_id, NULL);
+
+	/* Special case for EC: handle "orphan" _REG methods with no region */
+
+	if (space_id == ACPI_ADR_SPACE_EC) {
+		acpi_ev_orphan_ec_reg_method(node);
+	}
+
+	return_ACPI_STATUS(status);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ev_reg_run
+ *
+ * PARAMETERS:  walk_namespace callback
+ *
+ * DESCRIPTION: Run _REG method for region objects of the requested spaceID
+ *
+ ******************************************************************************/
+
+static acpi_status
+acpi_ev_reg_run(acpi_handle obj_handle,
+		u32 level, void *context, void **return_value)
+{
+	union acpi_operand_object *obj_desc;
+	struct acpi_namespace_node *node;
+	acpi_adr_space_type space_id;
+	acpi_status status;
+
+	space_id = *ACPI_CAST_PTR(acpi_adr_space_type, context);
+
+	/* Convert and validate the device handle */
+
+	node = acpi_ns_validate_handle(obj_handle);
+	if (!node) {
+		return (AE_BAD_PARAMETER);
+	}
+
+	/*
+	 * We only care about regions.and objects that are allowed to have address
+	 * space handlers
+	 */
+	if ((node->type != ACPI_TYPE_REGION) && (node != acpi_gbl_root_node)) {
+		return (AE_OK);
+	}
+
+	/* Check for an existing internal object */
+
+	obj_desc = acpi_ns_get_attached_object(node);
+	if (!obj_desc) {
+
+		/* No object, just exit */
+
+		return (AE_OK);
+	}
+
+	/* Object is a Region */
+
+	if (obj_desc->region.space_id != space_id) {
+
+		/* This region is for a different address space, just ignore it */
+
+		return (AE_OK);
+	}
+
+	status = acpi_ev_execute_reg_method(obj_desc, ACPI_REG_CONNECT);
+	return (status);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ev_orphan_ec_reg_method
+ *
+ * PARAMETERS:  ec_device_node      - Namespace node for an EC device
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Execute an "orphan" _REG method that appears under the EC
+ *              device. This is a _REG method that has no corresponding region
+ *              within the EC device scope. The orphan _REG method appears to
+ *              have been enabled by the description of the ECDT in the ACPI
+ *              specification: "The availability of the region space can be
+ *              detected by providing a _REG method object underneath the
+ *              Embedded Controller device."
+ *
+ *              To quickly access the EC device, we use the ec_device_node used
+ *              during EC handler installation. Otherwise, we would need to
+ *              perform a time consuming namespace walk, executing _HID
+ *              methods to find the EC device.
+ *
+ *  MUTEX:      Assumes the namespace is locked
+ *
+ ******************************************************************************/
+
+static void
+acpi_ev_orphan_ec_reg_method(struct acpi_namespace_node *ec_device_node)
+{
+	acpi_handle reg_method;
+	struct acpi_namespace_node *next_node;
+	acpi_status status;
+	struct acpi_object_list args;
+	union acpi_object objects[2];
+
+	ACPI_FUNCTION_TRACE(ev_orphan_ec_reg_method);
+
+	if (!ec_device_node) {
+		return_VOID;
+	}
+
+	/* Namespace is currently locked, must release */
+
+	(void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
+
+	/* Get a handle to a _REG method immediately under the EC device */
+
+	status = acpi_get_handle(ec_device_node, METHOD_NAME__REG, &reg_method);
+	if (ACPI_FAILURE(status)) {
+		goto exit;	/* There is no _REG method present */
+	}
+
+	/*
+	 * Execute the _REG method only if there is no Operation Region in
+	 * this scope with the Embedded Controller space ID. Otherwise, it
+	 * will already have been executed. Note, this allows for Regions
+	 * with other space IDs to be present; but the code below will then
+	 * execute the _REG method with the embedded_control space_ID argument.
+	 */
+	next_node = acpi_ns_get_next_node(ec_device_node, NULL);
+	while (next_node) {
+		if ((next_node->type == ACPI_TYPE_REGION) &&
+		    (next_node->object) &&
+		    (next_node->object->region.space_id == ACPI_ADR_SPACE_EC)) {
+			goto exit;	/* Do not execute the _REG */
+		}
+
+		next_node = acpi_ns_get_next_node(ec_device_node, next_node);
+	}
+
+	/* Evaluate the _REG(embedded_control,Connect) method */
+
+	args.count = 2;
+	args.pointer = objects;
+	objects[0].type = ACPI_TYPE_INTEGER;
+	objects[0].integer.value = ACPI_ADR_SPACE_EC;
+	objects[1].type = ACPI_TYPE_INTEGER;
+	objects[1].integer.value = ACPI_REG_CONNECT;
+
+	status = acpi_evaluate_object(reg_method, NULL, &args, NULL);
+
+exit:
+	/* We ignore all errors from above, don't care */
+
+	status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
+	return_VOID;
+}