[PATCH] fix semaphore handling in __unregister_chrdev_region

[linux/fpc-iii.git] / drivers / acpi / events / evregion.c

/******************************************************************************
 *
 * Module Name: evregion - ACPI address_space (op_region) handler dispatch
 *
 *****************************************************************************/

/*
 * Copyright (C) 2000 - 2005, R. Byron Moore
 * 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 <acpi/acevents.h>
#include <acpi/acnamesp.h>
#include <acpi/acinterp.h>

#define _COMPONENT          ACPI_EVENTS
         ACPI_MODULE_NAME    ("evregion")

#define ACPI_NUM_DEFAULT_SPACES     4

static u8                   acpi_gbl_default_address_spaces[ACPI_NUM_DEFAULT_SPACES] = {
                         ACPI_ADR_SPACE_SYSTEM_MEMORY,
                         ACPI_ADR_SPACE_SYSTEM_IO,
                         ACPI_ADR_SPACE_PCI_CONFIG,
                         ACPI_ADR_SPACE_DATA_TABLE};


/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_install_region_handlers
 *
 * PARAMETERS:  None
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Installs the core subsystem default address space handlers.
 *
 ******************************************************************************/

acpi_status
acpi_ev_install_region_handlers (
        void) {
        acpi_status                     status;
        acpi_native_uint                i;


        ACPI_FUNCTION_TRACE ("ev_install_region_handlers");


        status = acpi_ut_acquire_mutex (ACPI_MTX_NAMESPACE);
        if (ACPI_FAILURE (status)) {
                return_ACPI_STATUS (status);
        }

        /*
         * All address spaces (PCI Config, EC, SMBus) are scope dependent
         * and registration must occur for a specific device.
         *
         * In the case of the system memory and IO address spaces there is currently
         * no device associated with the address space.  For these we use the root.
         *
         * We install the default PCI config space handler at the root so
         * that this space is immediately available even though the we have
         * not enumerated all the PCI Root Buses yet.  This is to conform
         * to the ACPI specification which states that the PCI config
         * space must be always available -- even though we are nowhere
         * near ready to find the PCI root buses at this point.
         *
         * NOTE: We ignore AE_ALREADY_EXISTS because this means that a handler
         * has already been installed (via acpi_install_address_space_handler).
         * Similar for AE_SAME_HANDLER.
         */
        for (i = 0; i < ACPI_NUM_DEFAULT_SPACES; i++) {
                status = acpi_ev_install_space_handler (acpi_gbl_root_node,
                                  acpi_gbl_default_address_spaces[i],
                                  ACPI_DEFAULT_HANDLER, NULL, NULL);
                switch (status) {
                case AE_OK:
                case AE_SAME_HANDLER:
                case AE_ALREADY_EXISTS:

                        /* These exceptions are all OK */

                        status = AE_OK;
                        break;

                default:

                        goto unlock_and_exit;
                }
        }

unlock_and_exit:
        (void) acpi_ut_release_mutex (ACPI_MTX_NAMESPACE);
        return_ACPI_STATUS (status);
}


/*******************************************************************************
 *
 * 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;
        acpi_native_uint                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++) {
                /* TBD: Make sure handler is the DEFAULT handler, otherwise
                 * _REG will have already been run.
                 */
                status = acpi_ev_execute_reg_methods (acpi_gbl_root_node,
                                  acpi_gbl_default_address_spaces[i]);
        }

        (void) acpi_ut_release_mutex (ACPI_MTX_NAMESPACE);
        return_ACPI_STATUS (status);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_execute_reg_method
 *
 * PARAMETERS:  region_obj          - Object structure
 *              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_parameter_info      info;
        union acpi_operand_object       *params[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);
        }

        /*
         * 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
         */
        params[0] = acpi_ut_create_internal_object (ACPI_TYPE_INTEGER);
        if (!params[0]) {
                return_ACPI_STATUS (AE_NO_MEMORY);
        }

        params[1] = acpi_ut_create_internal_object (ACPI_TYPE_INTEGER);
        if (!params[1]) {
                status = AE_NO_MEMORY;
                goto cleanup;
        }

        /* Setup the parameter objects */

        params[0]->integer.value = region_obj->region.space_id;
        params[1]->integer.value = function;
        params[2] = NULL;

        info.node = region_obj2->extra.method_REG;
        info.parameters = params;
        info.parameter_type = ACPI_PARAM_ARGS;

        /* Execute the method, no return value */

        ACPI_DEBUG_EXEC (acpi_ut_display_init_pathname (
                           ACPI_TYPE_METHOD, info.node, NULL));
        status = acpi_ns_evaluate_by_handle (&info);

        acpi_ut_remove_reference (params[1]);

cleanup:
        acpi_ut_remove_reference (params[0]);

        return_ACPI_STATUS (status);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_address_space_dispatch
 *
 * PARAMETERS:  region_obj          - Internal region object
 *              Function            - Read or Write operation
 *              Address             - Where in the space to read or write
 *              bit_width           - Field width in bits (8, 16, 32, or 64)
 *              Value               - Pointer to in or out value
 *
 * 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,
        u32                             function,
        acpi_physical_address           address,
        u32                             bit_width,
        void                            *value)
{
        acpi_status                     status;
        acpi_status                     status2;
        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;


        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_DEBUG_PRINT ((ACPI_DB_ERROR,
                        "No handler for Region [%4.4s] (%p) [%s]\n",
                        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);
        }

        /*
         * 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_DEBUG_PRINT ((ACPI_DB_ERROR, "No init routine for region(%p) [%s]\n",
                                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 (e.g., _REG method for this region)
                 */
                acpi_ex_exit_interpreter ();

                status = region_setup (region_obj, ACPI_REGION_ACTIVATE,
                                  handler_desc->address_space.context, &region_context);

                /* Re-enter the interpreter */

                status2 = acpi_ex_enter_interpreter ();
                if (ACPI_FAILURE (status2)) {
                        return_ACPI_STATUS (status2);
                }

                /* Check for failure of the Region Setup */

                if (ACPI_FAILURE (status)) {
                        ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "Region Init: %s [%s]\n",
                                acpi_format_exception (status),
                                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;

                        if (region_obj2->extra.region_context) {
                                /* The handler for this region was already installed */

                                ACPI_MEM_FREE (region_context);
                        }
                        else {
                                /*
                                 * Save the returned context for use in all accesses to
                                 * this particular region
                                 */
                                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;

        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.hflags & 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,
                         handler_desc->address_space.context,
                         region_obj2->extra.region_context);

        if (ACPI_FAILURE (status)) {
                ACPI_REPORT_ERROR (("Handler for [%s] returned %s\n",
                        acpi_ut_get_region_name (region_obj->region.space_id),
                        acpi_format_exception (status)));
        }

        if (!(handler_desc->address_space.hflags & ACPI_ADDR_HANDLER_DEFAULT_INSTALLED)) {
                /*
                 * We just returned from a non-default handler, we must re-enter the
                 * interpreter
                 */
                status2 = acpi_ex_enter_interpreter ();
                if (ACPI_FAILURE (status2)) {
                        return_ACPI_STATUS (status2);
                }
        }

        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       **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;
        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, 0);
                        if (ACPI_FAILURE (status)) {
                                ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "%s from region _REG, [%s]\n",
                                        acpi_format_exception (status),
                                        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;
                                }
                        }

                        /* Call the setup handler with the deactivate notification */

                        region_setup = handler_obj->address_space.setup;
                        status = region_setup (region_obj, ACPI_REGION_DEACTIVATE,
                                          handler_obj->address_space.context, region_context);

                        /* Init routine may fail, Just ignore errors */

                        if (ACPI_FAILURE (status)) {
                                ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "%s from region init, [%s]\n",
                                        acpi_format_exception (status),
                                        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 better 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;
        }

        /* 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_install_handler
 *
 * PARAMETERS:  walk_namespace callback
 *
 * DESCRIPTION: This routine installs an address handler into objects that are
 *              of type Region or Device.
 *
 *              If the Object is a Device, and the device has a handler of
 *              the same type then the search is terminated in that branch.
 *
 *              This is because the existing handler is closer in proximity
 *              to any more regions than the one we are trying to install.
 *
 ******************************************************************************/

acpi_status
acpi_ev_install_handler (
        acpi_handle                     obj_handle,
        u32                             level,
        void                            *context,
        void                            **return_value)
{
        union acpi_operand_object       *handler_obj;
        union acpi_operand_object       *next_handler_obj;
        union acpi_operand_object       *obj_desc;
        struct acpi_namespace_node      *node;
        acpi_status                     status;


        ACPI_FUNCTION_NAME ("ev_install_handler");


        handler_obj = (union acpi_operand_object   *) context;

        /* Parameter validation */

        if (!handler_obj) {
                return (AE_OK);
        }

        /* Convert and validate the device handle */

        node = acpi_ns_map_handle_to_node (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_DEVICE) &&
                (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);
        }

        /* Devices are handled different than regions */

        if (ACPI_GET_OBJECT_TYPE (obj_desc) == ACPI_TYPE_DEVICE) {
                /* Check if this Device already has a handler for this address space */

                next_handler_obj = obj_desc->device.handler;
                while (next_handler_obj) {
                        /* Found a handler, is it for the same address space? */

                        if (next_handler_obj->address_space.space_id == handler_obj->address_space.space_id) {
                                ACPI_DEBUG_PRINT ((ACPI_DB_OPREGION,
                                        "Found handler for region [%s] in device %p(%p) handler %p\n",
                                        acpi_ut_get_region_name (handler_obj->address_space.space_id),
                                        obj_desc, next_handler_obj, handler_obj));

                                /*
                                 * Since the object we found it on was a device, then it
                                 * means that someone has already installed a handler for
                                 * the branch of the namespace from this device on.  Just
                                 * bail out telling the walk routine to not traverse this
                                 * branch.  This preserves the scoping rule for handlers.
                                 */
                                return (AE_CTRL_DEPTH);
                        }

                        /* Walk the linked list of handlers attached to this device */

                        next_handler_obj = next_handler_obj->address_space.next;
                }

                /*
                 * As long as the device didn't have a handler for this
                 * space we don't care about it.  We just ignore it and
                 * proceed.
                 */
                return (AE_OK);
        }

        /* Object is a Region */

        if (obj_desc->region.space_id != handler_obj->address_space.space_id) {
                /*
                 * This region is for a different address space
                 * -- just ignore it
                 */
                return (AE_OK);
        }

        /*
         * Now we have a region and it is for the handler's address
         * space type.
         *
         * First disconnect region for any previous handler (if any)
         */
        acpi_ev_detach_region (obj_desc, FALSE);

        /* Connect the region to the new handler */

        status = acpi_ev_attach_region (handler_obj, obj_desc, FALSE);
        return (status);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_install_space_handler
 *
 * PARAMETERS:  Node            - Namespace node for the device
 *              space_id        - The address space ID
 *              Handler         - Address of the handler
 *              Setup           - Address of the setup function
 *              Context         - Value passed to the handler on each access
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Install a handler for all op_regions of a given space_id.
 *              Assumes namespace is locked
 *
 ******************************************************************************/

acpi_status
acpi_ev_install_space_handler (
        struct acpi_namespace_node      *node,
        acpi_adr_space_type             space_id,
        acpi_adr_space_handler          handler,
        acpi_adr_space_setup            setup,
        void                            *context)
{
        union acpi_operand_object       *obj_desc;
        union acpi_operand_object       *handler_obj;
        acpi_status                     status;
        acpi_object_type                type;
        u16                             flags = 0;


        ACPI_FUNCTION_TRACE ("ev_install_space_handler");


        /*
         * This registration is valid for only the types below
         * and the root.  This is where the default handlers
         * get placed.
         */
        if ((node->type != ACPI_TYPE_DEVICE)     &&
                (node->type != ACPI_TYPE_PROCESSOR)  &&
                (node->type != ACPI_TYPE_THERMAL)    &&
                (node != acpi_gbl_root_node)) {
                status = AE_BAD_PARAMETER;
                goto unlock_and_exit;
        }

        if (handler == ACPI_DEFAULT_HANDLER) {
                flags = ACPI_ADDR_HANDLER_DEFAULT_INSTALLED;

                switch (space_id) {
                case ACPI_ADR_SPACE_SYSTEM_MEMORY:
                        handler = acpi_ex_system_memory_space_handler;
                        setup   = acpi_ev_system_memory_region_setup;
                        break;

                case ACPI_ADR_SPACE_SYSTEM_IO:
                        handler = acpi_ex_system_io_space_handler;
                        setup   = acpi_ev_io_space_region_setup;
                        break;

                case ACPI_ADR_SPACE_PCI_CONFIG:
                        handler = acpi_ex_pci_config_space_handler;
                        setup   = acpi_ev_pci_config_region_setup;
                        break;

                case ACPI_ADR_SPACE_CMOS:
                        handler = acpi_ex_cmos_space_handler;
                        setup   = acpi_ev_cmos_region_setup;
                        break;

                case ACPI_ADR_SPACE_PCI_BAR_TARGET:
                        handler = acpi_ex_pci_bar_space_handler;
                        setup   = acpi_ev_pci_bar_region_setup;
                        break;

                case ACPI_ADR_SPACE_DATA_TABLE:
                        handler = acpi_ex_data_table_space_handler;
                        setup   = NULL;
                        break;

                default:
                        status = AE_BAD_PARAMETER;
                        goto unlock_and_exit;
                }
        }

        /* If the caller hasn't specified a setup routine, use the default */

        if (!setup) {
                setup = acpi_ev_default_region_setup;
        }

        /* Check for an existing internal object */

        obj_desc = acpi_ns_get_attached_object (node);
        if (obj_desc) {
                /*
                 * The attached device object already exists.
                 * Make sure the handler is not already installed.
                 */
                handler_obj = obj_desc->device.handler;

                /* Walk the handler list for this device */

                while (handler_obj) {
                        /* Same space_id indicates a handler already installed */

                        if (handler_obj->address_space.space_id == space_id) {
                                if (handler_obj->address_space.handler == handler) {
                                        /*
                                         * It is (relatively) OK to attempt to install the SAME
                                         * handler twice. This can easily happen with PCI_Config space.
                                         */
                                        status = AE_SAME_HANDLER;
                                        goto unlock_and_exit;
                                }
                                else {
                                        /* A handler is already installed */

                                        status = AE_ALREADY_EXISTS;
                                }
                                goto unlock_and_exit;
                        }

                        /* Walk the linked list of handlers */

                        handler_obj = handler_obj->address_space.next;
                }
        }
        else {
                ACPI_DEBUG_PRINT ((ACPI_DB_OPREGION,
                        "Creating object on Device %p while installing handler\n", node));

                /* obj_desc does not exist, create one */

                if (node->type == ACPI_TYPE_ANY) {
                        type = ACPI_TYPE_DEVICE;
                }
                else {
                        type = node->type;
                }

                obj_desc = acpi_ut_create_internal_object (type);
                if (!obj_desc) {
                        status = AE_NO_MEMORY;
                        goto unlock_and_exit;
                }

                /* Init new descriptor */

                obj_desc->common.type = (u8) type;

                /* Attach the new object to the Node */

                status = acpi_ns_attach_object (node, obj_desc, type);

                /* Remove local reference to the object */

                acpi_ut_remove_reference (obj_desc);

                if (ACPI_FAILURE (status)) {
                        goto unlock_and_exit;
                }
        }

        ACPI_DEBUG_PRINT ((ACPI_DB_OPREGION,
                "Installing address handler for region %s(%X) on Device %4.4s %p(%p)\n",
                acpi_ut_get_region_name (space_id), space_id,
                acpi_ut_get_node_name (node), node, obj_desc));

        /*
         * Install the handler
         *
         * At this point there is no existing handler.
         * Just allocate the object for the handler and link it
         * into the list.
         */
        handler_obj = acpi_ut_create_internal_object (ACPI_TYPE_LOCAL_ADDRESS_HANDLER);
        if (!handler_obj) {
                status = AE_NO_MEMORY;
                goto unlock_and_exit;
        }

        /* Init handler obj */

        handler_obj->address_space.space_id  = (u8) space_id;
        handler_obj->address_space.hflags    = flags;
        handler_obj->address_space.region_list = NULL;
        handler_obj->address_space.node      = node;
        handler_obj->address_space.handler   = handler;
        handler_obj->address_space.context   = context;
        handler_obj->address_space.setup     = setup;

        /* Install at head of Device.address_space list */

        handler_obj->address_space.next      = obj_desc->device.handler;

        /*
         * The Device object is the first reference on the handler_obj.
         * Each region that uses the handler adds a reference.
         */
        obj_desc->device.handler = handler_obj;

        /*
         * Walk the namespace finding all of the regions this
         * handler will manage.
         *
         * Start at the device and search the branch toward
         * the leaf nodes until either the leaf is encountered or
         * a device is detected that has an address handler of the
         * same type.
         *
         * In either case, back up and search down the remainder
         * of the branch
         */
        status = acpi_ns_walk_namespace (ACPI_TYPE_ANY, node, ACPI_UINT32_MAX,
                          ACPI_NS_WALK_UNLOCK, acpi_ev_install_handler,
                          handler_obj, NULL);

unlock_and_exit:
        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,
                          &space_id, NULL);

        return_ACPI_STATUS (status);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_reg_run
 *
 * PARAMETERS:  walk_namespace callback
 *
 * DESCRIPTION: Run _REg method for region objects of the requested space_iD
 *
 ******************************************************************************/

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_map_handle_to_node (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, 1);
        return (status);
}