evregion.c

Go to the documentation of this file.

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

/*
 * Copyright (C) 2000 - 2012, 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")

/* Local prototypes */
static u8
acpi_ev_has_default_handler(struct acpi_namespace_node *node,
                acpi_adr_space_type space_id);

static void acpi_ev_orphan_ec_reg_method(void);

static acpi_status
acpi_ev_reg_run(acpi_handle obj_handle,
        u32 level, void *context, void **return_value);

static acpi_status
acpi_ev_install_handler(acpi_handle obj_handle,
            u32 level, void *context, void **return_value);

/* These are the address spaces that will get default handlers */

#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;
    u32 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_has_default_handler
 *
 * PARAMETERS:  node                - Namespace node for the device
 *              space_id            - The address space ID
 *
 * RETURN:      TRUE if default handler is installed, FALSE otherwise
 *
 * DESCRIPTION: Check if the default handler is installed for the requested
 *              space ID.
 *
 ******************************************************************************/

static u8
acpi_ev_has_default_handler(struct acpi_namespace_node *node,
                acpi_adr_space_type space_id)
{
    union acpi_operand_object *obj_desc;
    union acpi_operand_object *handler_obj;

    /* Must have an existing internal object */

    obj_desc = acpi_ns_get_attached_object(node);
    if (obj_desc) {
        handler_obj = obj_desc->device.handler;

        /* Walk the linked list of handlers for this object */

        while (handler_obj) {
            if (handler_obj->address_space.space_id == space_id) {
                if (handler_obj->address_space.handler_flags &
                    ACPI_ADDR_HANDLER_DEFAULT_INSTALLED) {
                    return (TRUE);
                }
            }

            handler_obj = handler_obj->address_space.next;
        }
    }

    return (FALSE);
}

/*******************************************************************************
 *
 * 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_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->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_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_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;

            if (region_obj2->extra.region_context) {

                /* The handler for this region was already installed */

                ACPI_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_NATIVE_UINT(region_obj->region.address +
                          region_offset),
              acpi_ut_get_region_name(region_obj->region.
                          space_id)));

    /*
     * 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.
     */
    if (((region_obj->region.space_id == ACPI_ADR_SPACE_GSBUS) ||
         (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;
    }

    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,
             (region_obj->region.address + region_offset),
             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 **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,
                               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);

                /* 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;
    }

    /* 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.
 *
 ******************************************************************************/

static 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_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_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 (obj_desc->common.type == 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;
    u8 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 the
                     * 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.handler_flags = 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, NULL,
                    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,
                    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();
    }

    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:  None
 *
 * 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_ID that appears
 *              within the ECDT. Otherwise, we would need to perform a time-
 *              consuming namespace walk, executing _HID methods to find the
 *              EC device.
 *
 ******************************************************************************/

static void acpi_ev_orphan_ec_reg_method(void)
{
    struct acpi_table_ecdt *table;
    acpi_status status;
    struct acpi_object_list args;
    union acpi_object objects[2];
    struct acpi_namespace_node *ec_device_node;
    struct acpi_namespace_node *reg_method;
    struct acpi_namespace_node *next_node;

    ACPI_FUNCTION_TRACE(ev_orphan_ec_reg_method);

    /* Get the ECDT (if present in system) */

    status = acpi_get_table(ACPI_SIG_ECDT, 0,
                ACPI_CAST_INDIRECT_PTR(struct acpi_table_header,
                               &table));
    if (ACPI_FAILURE(status)) {
        return_VOID;
    }

    /* We need a valid EC_ID string */

    if (!(*table->id)) {
        return_VOID;
    }

    /* Namespace is currently locked, must release */

    (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);

    /* Get a handle to the EC device referenced in the ECDT */

    status = acpi_get_handle(NULL,
                 ACPI_CAST_PTR(char, table->id),
                 ACPI_CAST_PTR(acpi_handle, &ec_device_node));
    if (ACPI_FAILURE(status)) {
        goto exit;
    }

    /* Get a handle to a _REG method immediately under the EC device */

    status = acpi_get_handle(ec_device_node,
                 METHOD_NAME__REG, ACPI_CAST_PTR(acpi_handle,
                                 &reg_method));
    if (ACPI_FAILURE(status)) {
        goto exit;
    }

    /*
     * 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 EC 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 _REG */
        }
        next_node = acpi_ns_get_next_node(ec_device_node, next_node);
    }

    /* Evaluate the _REG(EC,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;
}