/******************************************************************************
 *
 * Module Name: evgpe - General Purpose Event handling and dispatch
 *
 *****************************************************************************/

/*
 * Copyright (C) 2000 - 2014, Intel Corp.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    substantially similar to the "NO WARRANTY" disclaimer below
 *    ("Disclaimer") and any redistribution must be conditioned upon
 *    including a substantially similar Disclaimer requirement for further
 *    binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * NO WARRANTY
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 */

#include <acpi/acpi.h>
#include "accommon.h"
#include "acevents.h"
#include "acnamesp.h"

#define _COMPONENT          ACPI_EVENTS
ACPI_MODULE_NAME("evgpe")
#if (!ACPI_REDUCED_HARDWARE)    /* Entire module */
/* Local prototypes */
static void ACPI_SYSTEM_XFACE acpi_ev_asynch_execute_gpe_method(void *context);

static void ACPI_SYSTEM_XFACE acpi_ev_asynch_enable_gpe(void *context);

/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_update_gpe_enable_mask
 *
 * PARAMETERS:  gpe_event_info          - GPE to update
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Updates GPE register enable mask based upon whether there are
 *              runtime references to this GPE
 *
 ******************************************************************************/

acpi_status
acpi_ev_update_gpe_enable_mask(struct acpi_gpe_event_info *gpe_event_info)
{
        struct acpi_gpe_register_info *gpe_register_info;
        u32 register_bit;

        ACPI_FUNCTION_TRACE(ev_update_gpe_enable_mask);

        gpe_register_info = gpe_event_info->register_info;
        if (!gpe_register_info) {
                return_ACPI_STATUS(AE_NOT_EXIST);
        }

        register_bit = acpi_hw_get_gpe_register_bit(gpe_event_info);

        /* Clear the run bit up front */

        ACPI_CLEAR_BIT(gpe_register_info->enable_for_run, register_bit);

        /* Set the mask bit only if there are references to this GPE */

        if (gpe_event_info->runtime_count) {
                ACPI_SET_BIT(gpe_register_info->enable_for_run,
                             (u8)register_bit);
        }

        return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_enable_gpe
 *
 * PARAMETERS:  gpe_event_info  - GPE to enable
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Clear a GPE of stale events and enable it.
 *
 ******************************************************************************/
acpi_status acpi_ev_enable_gpe(struct acpi_gpe_event_info *gpe_event_info)
{
        acpi_status status;

        ACPI_FUNCTION_TRACE(ev_enable_gpe);

        /*
         * We will only allow a GPE to be enabled if it has either an associated
         * method (_Lxx/_Exx) or a handler, or is using the implicit notify
         * feature. Otherwise, the GPE will be immediately disabled by
         * acpi_ev_gpe_dispatch the first time it fires.
         */
        if ((gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) ==
            ACPI_GPE_DISPATCH_NONE) {
                return_ACPI_STATUS(AE_NO_HANDLER);
        }

        /* Clear the GPE (of stale events) */
        status = acpi_hw_clear_gpe(gpe_event_info);
        if (ACPI_FAILURE(status)) {
                return_ACPI_STATUS(status);
        }

        /* Enable the requested GPE */

        status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_ENABLE);
        return_ACPI_STATUS(status);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_add_gpe_reference
 *
 * PARAMETERS:  gpe_event_info          - Add a reference to this GPE
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Add a reference to a GPE. On the first reference, the GPE is
 *              hardware-enabled.
 *
 ******************************************************************************/

acpi_status
acpi_ev_add_gpe_reference(struct acpi_gpe_event_info *gpe_event_info)
{
        acpi_status status = AE_OK;

        ACPI_FUNCTION_TRACE(ev_add_gpe_reference);

        if (gpe_event_info->runtime_count == ACPI_UINT8_MAX) {
                return_ACPI_STATUS(AE_LIMIT);
        }

        gpe_event_info->runtime_count++;
        if (gpe_event_info->runtime_count == 1) {

                /* Enable on first reference */

                status = acpi_ev_update_gpe_enable_mask(gpe_event_info);
                if (ACPI_SUCCESS(status)) {
                        status = acpi_ev_enable_gpe(gpe_event_info);
                }

                if (ACPI_FAILURE(status)) {
                        gpe_event_info->runtime_count--;
                }
        }

        return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_remove_gpe_reference
 *
 * PARAMETERS:  gpe_event_info          - Remove a reference to this GPE
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Remove a reference to a GPE. When the last reference is
 *              removed, the GPE is hardware-disabled.
 *
 ******************************************************************************/

acpi_status
acpi_ev_remove_gpe_reference(struct acpi_gpe_event_info *gpe_event_info)
{
        acpi_status status = AE_OK;

        ACPI_FUNCTION_TRACE(ev_remove_gpe_reference);

        if (!gpe_event_info->runtime_count) {
                return_ACPI_STATUS(AE_LIMIT);
        }

        gpe_event_info->runtime_count--;
        if (!gpe_event_info->runtime_count) {

                /* Disable on last reference */

                status = acpi_ev_update_gpe_enable_mask(gpe_event_info);
                if (ACPI_SUCCESS(status)) {
                        status =
                            acpi_hw_low_set_gpe(gpe_event_info,
                                                     ACPI_GPE_DISABLE);
                }

                if (ACPI_FAILURE(status)) {
                        gpe_event_info->runtime_count++;
                }
        }

        return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_low_get_gpe_info
 *
 * PARAMETERS:  gpe_number          - Raw GPE number
 *              gpe_block           - A GPE info block
 *
 * RETURN:      A GPE event_info struct. NULL if not a valid GPE (The gpe_number
 *              is not within the specified GPE block)
 *
 * DESCRIPTION: Returns the event_info struct associated with this GPE. This is
 *              the low-level implementation of ev_get_gpe_event_info.
 *
 ******************************************************************************/

struct acpi_gpe_event_info *acpi_ev_low_get_gpe_info(u32 gpe_number,
                                                     struct acpi_gpe_block_info
                                                     *gpe_block)
{
        u32 gpe_index;

        /*
         * Validate that the gpe_number is within the specified gpe_block.
         * (Two steps)
         */
        if (!gpe_block || (gpe_number < gpe_block->block_base_number)) {
                return (NULL);
        }

        gpe_index = gpe_number - gpe_block->block_base_number;
        if (gpe_index >= gpe_block->gpe_count) {
                return (NULL);
        }

        return (&gpe_block->event_info[gpe_index]);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_get_gpe_event_info
 *
 * PARAMETERS:  gpe_device          - Device node. NULL for GPE0/GPE1
 *              gpe_number          - Raw GPE number
 *
 * RETURN:      A GPE event_info struct. NULL if not a valid GPE
 *
 * DESCRIPTION: Returns the event_info struct associated with this GPE.
 *              Validates the gpe_block and the gpe_number
 *
 *              Should be called only when the GPE lists are semaphore locked
 *              and not subject to change.
 *
 ******************************************************************************/

struct acpi_gpe_event_info *acpi_ev_get_gpe_event_info(acpi_handle gpe_device,
                                                       u32 gpe_number)
{
        union acpi_operand_object *obj_desc;
        struct acpi_gpe_event_info *gpe_info;
        u32 i;

        ACPI_FUNCTION_ENTRY();

        /* A NULL gpe_device means use the FADT-defined GPE block(s) */

        if (!gpe_device) {

                /* Examine GPE Block 0 and 1 (These blocks are permanent) */

                for (i = 0; i < ACPI_MAX_GPE_BLOCKS; i++) {
                        gpe_info = acpi_ev_low_get_gpe_info(gpe_number,
                                                            acpi_gbl_gpe_fadt_blocks
                                                            [i]);
                        if (gpe_info) {
                                return (gpe_info);
                        }
                }

                /* The gpe_number was not in the range of either FADT GPE block */

                return (NULL);
        }

        /* A Non-NULL gpe_device means this is a GPE Block Device */

        obj_desc =
            acpi_ns_get_attached_object((struct acpi_namespace_node *)
                                               gpe_device);
        if (!obj_desc || !obj_desc->device.gpe_block) {
                return (NULL);
        }

        return (acpi_ev_low_get_gpe_info
                (gpe_number, obj_desc->device.gpe_block));
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_gpe_detect
 *
 * PARAMETERS:  gpe_xrupt_list      - Interrupt block for this interrupt.
 *                                    Can have multiple GPE blocks attached.
 *
 * RETURN:      INTERRUPT_HANDLED or INTERRUPT_NOT_HANDLED
 *
 * DESCRIPTION: Detect if any GP events have occurred. This function is
 *              executed at interrupt level.
 *
 ******************************************************************************/

u32 acpi_ev_gpe_detect(struct acpi_gpe_xrupt_info * gpe_xrupt_list)
{
        acpi_status status;
        struct acpi_gpe_block_info *gpe_block;
        struct acpi_gpe_register_info *gpe_register_info;
        u32 int_status = ACPI_INTERRUPT_NOT_HANDLED;
        u8 enabled_status_byte;
        u32 status_reg;
        u32 enable_reg;
        acpi_cpu_flags flags;
        u32 i;
        u32 j;

        ACPI_FUNCTION_NAME(ev_gpe_detect);

        /* Check for the case where there are no GPEs */

        if (!gpe_xrupt_list) {
                return (int_status);
        }

        /*
         * We need to obtain the GPE lock for both the data structs and registers
         * Note: Not necessary to obtain the hardware lock, since the GPE
         * registers are owned by the gpe_lock.
         */
        flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);

        /* Examine all GPE blocks attached to this interrupt level */

        gpe_block = gpe_xrupt_list->gpe_block_list_head;
        while (gpe_block) {
                /*
                 * Read all of the 8-bit GPE status and enable registers in this GPE
                 * block, saving all of them. Find all currently active GP events.
                 */
                for (i = 0; i < gpe_block->register_count; i++) {

                        /* Get the next status/enable pair */

                        gpe_register_info = &gpe_block->register_info[i];

                        /*
                         * Optimization: If there are no GPEs enabled within this
                         * register, we can safely ignore the entire register.
                         */
                        if (!(gpe_register_info->enable_for_run |
                              gpe_register_info->enable_for_wake)) {
                                ACPI_DEBUG_PRINT((ACPI_DB_INTERRUPTS,
                                                  "Ignore disabled registers for GPE %02X-%02X: "
                                                  "RunEnable=%02X, WakeEnable=%02X\n",
                                                  gpe_register_info->
                                                  base_gpe_number,
                                                  gpe_register_info->
                                                  base_gpe_number +
                                                  (ACPI_GPE_REGISTER_WIDTH - 1),
                                                  gpe_register_info->
                                                  enable_for_run,
                                                  gpe_register_info->
                                                  enable_for_wake));
                                continue;
                        }

                        /* Read the Status Register */

                        status =
                            acpi_hw_read(&status_reg,
                                         &gpe_register_info->status_address);
                        if (ACPI_FAILURE(status)) {
                                goto unlock_and_exit;
                        }

                        /* Read the Enable Register */

                        status =
                            acpi_hw_read(&enable_reg,
                                         &gpe_register_info->enable_address);
                        if (ACPI_FAILURE(status)) {
                                goto unlock_and_exit;
                        }

                        ACPI_DEBUG_PRINT((ACPI_DB_INTERRUPTS,
                                          "Read registers for GPE %02X-%02X: Status=%02X, Enable=%02X, "
                                          "RunEnable=%02X, WakeEnable=%02X\n",
                                          gpe_register_info->base_gpe_number,
                                          gpe_register_info->base_gpe_number +
                                          (ACPI_GPE_REGISTER_WIDTH - 1),
                                          status_reg, enable_reg,
                                          gpe_register_info->enable_for_run,
                                          gpe_register_info->enable_for_wake));

                        /* Check if there is anything active at all in this register */

                        enabled_status_byte = (u8) (status_reg & enable_reg);
                        if (!enabled_status_byte) {

                                /* No active GPEs in this register, move on */

                                continue;
                        }

                        /* Now look at the individual GPEs in this byte register */

                        for (j = 0; j < ACPI_GPE_REGISTER_WIDTH; j++) {

                                /* Examine one GPE bit */

                                if (enabled_status_byte & (1 << j)) {
                                        /*
                                         * Found an active GPE. Dispatch the event to a handler
                                         * or method.
                                         */
                                        int_status |=
                                            acpi_ev_gpe_dispatch(gpe_block->
                                                                 node,
                                                                 &gpe_block->
                                                event_info[((acpi_size) i * ACPI_GPE_REGISTER_WIDTH) + j], j + gpe_register_info->base_gpe_number);
                                }
                        }
                }

                gpe_block = gpe_block->next;
        }

unlock_and_exit:

        acpi_os_release_lock(acpi_gbl_gpe_lock, flags);
        return (int_status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_asynch_execute_gpe_method
 *
 * PARAMETERS:  Context (gpe_event_info) - Info for this GPE
 *
 * RETURN:      None
 *
 * DESCRIPTION: Perform the actual execution of a GPE control method. This
 *              function is called from an invocation of acpi_os_execute and
 *              therefore does NOT execute at interrupt level - so that
 *              the control method itself is not executed in the context of
 *              an interrupt handler.
 *
 ******************************************************************************/

static void ACPI_SYSTEM_XFACE acpi_ev_asynch_execute_gpe_method(void *context)
{
        struct acpi_gpe_event_info *gpe_event_info = context;
        acpi_status status;
        struct acpi_gpe_event_info *local_gpe_event_info;
        struct acpi_evaluate_info *info;
        struct acpi_gpe_notify_info *notify;

        ACPI_FUNCTION_TRACE(ev_asynch_execute_gpe_method);

        /* Allocate a local GPE block */

        local_gpe_event_info =
            ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_gpe_event_info));
        if (!local_gpe_event_info) {
                ACPI_EXCEPTION((AE_INFO, AE_NO_MEMORY, "while handling a GPE"));
                return_VOID;
        }

        status = acpi_ut_acquire_mutex(ACPI_MTX_EVENTS);
        if (ACPI_FAILURE(status)) {
                ACPI_FREE(local_gpe_event_info);
                return_VOID;
        }

        /* Must revalidate the gpe_number/gpe_block */

        if (!acpi_ev_valid_gpe_event(gpe_event_info)) {
                status = acpi_ut_release_mutex(ACPI_MTX_EVENTS);
                ACPI_FREE(local_gpe_event_info);
                return_VOID;
        }

        /*
         * Take a snapshot of the GPE info for this level - we copy the info to
         * prevent a race condition with remove_handler/remove_block.
         */
        ACPI_MEMCPY(local_gpe_event_info, gpe_event_info,
                    sizeof(struct acpi_gpe_event_info));

        status = acpi_ut_release_mutex(ACPI_MTX_EVENTS);
        if (ACPI_FAILURE(status)) {
                ACPI_FREE(local_gpe_event_info);
                return_VOID;
        }

        /* Do the correct dispatch - normal method or implicit notify */

        switch (local_gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) {
        case ACPI_GPE_DISPATCH_NOTIFY:
                /*
                 * Implicit notify.
                 * Dispatch a DEVICE_WAKE notify to the appropriate handler.
                 * NOTE: the request is queued for execution after this method
                 * completes. The notify handlers are NOT invoked synchronously
                 * from this thread -- because handlers may in turn run other
                 * control methods.
                 *
                 * June 2012: Expand implicit notify mechanism to support
                 * notifies on multiple device objects.
                 */
                notify = local_gpe_event_info->dispatch.notify_list;
                while (ACPI_SUCCESS(status) && notify) {
                        status =
                            acpi_ev_queue_notify_request(notify->device_node,
                                                         ACPI_NOTIFY_DEVICE_WAKE);

                        notify = notify->next;
                }

                break;

        case ACPI_GPE_DISPATCH_METHOD:

                /* Allocate the evaluation information block */

                info = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_evaluate_info));
                if (!info) {
                        status = AE_NO_MEMORY;
                } else {
                        /*
                         * Invoke the GPE Method (_Lxx, _Exx) i.e., evaluate the
                         * _Lxx/_Exx control method that corresponds to this GPE
                         */
                        info->prefix_node =
                            local_gpe_event_info->dispatch.method_node;
                        info->flags = ACPI_IGNORE_RETURN_VALUE;

                        status = acpi_ns_evaluate(info);
                        ACPI_FREE(info);
                }

                if (ACPI_FAILURE(status)) {
                        ACPI_EXCEPTION((AE_INFO, status,
                                        "while evaluating GPE method [%4.4s]",
                                        acpi_ut_get_node_name
                                        (local_gpe_event_info->dispatch.
                                         method_node)));
                }
                break;

        default:

                return_VOID;    /* Should never happen */
        }

        /* Defer enabling of GPE until all notify handlers are done */

        status = acpi_os_execute(OSL_NOTIFY_HANDLER,
                                 acpi_ev_asynch_enable_gpe,
                                 local_gpe_event_info);
        if (ACPI_FAILURE(status)) {
                ACPI_FREE(local_gpe_event_info);
        }
        return_VOID;
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_asynch_enable_gpe
 *
 * PARAMETERS:  Context (gpe_event_info) - Info for this GPE
 *              Callback from acpi_os_execute
 *
 * RETURN:      None
 *
 * DESCRIPTION: Asynchronous clear/enable for GPE. This allows the GPE to
 *              complete (i.e., finish execution of Notify)
 *
 ******************************************************************************/

static void ACPI_SYSTEM_XFACE acpi_ev_asynch_enable_gpe(void *context)
{
        struct acpi_gpe_event_info *gpe_event_info = context;

        (void)acpi_ev_finish_gpe(gpe_event_info);

        ACPI_FREE(gpe_event_info);
        return;
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_finish_gpe
 *
 * PARAMETERS:  gpe_event_info      - Info for this GPE
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Clear/Enable a GPE. Common code that is used after execution
 *              of a GPE method or a synchronous or asynchronous GPE handler.
 *
 ******************************************************************************/

acpi_status acpi_ev_finish_gpe(struct acpi_gpe_event_info *gpe_event_info)
{
        acpi_status status;

        if ((gpe_event_info->flags & ACPI_GPE_XRUPT_TYPE_MASK) ==
            ACPI_GPE_LEVEL_TRIGGERED) {
                /*
                 * GPE is level-triggered, we clear the GPE status bit after
                 * handling the event.
                 */
                status = acpi_hw_clear_gpe(gpe_event_info);
                if (ACPI_FAILURE(status)) {
                        return (status);
                }
        }

        /*
         * Enable this GPE, conditionally. This means that the GPE will
         * only be physically enabled if the enable_for_run bit is set
         * in the event_info.
         */
        (void)acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_CONDITIONAL_ENABLE);
        return (AE_OK);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_gpe_dispatch
 *
 * PARAMETERS:  gpe_device      - Device node. NULL for GPE0/GPE1
 *              gpe_event_info  - Info for this GPE
 *              gpe_number      - Number relative to the parent GPE block
 *
 * RETURN:      INTERRUPT_HANDLED or INTERRUPT_NOT_HANDLED
 *
 * DESCRIPTION: Dispatch a General Purpose Event to either a function (e.g. EC)
 *              or method (e.g. _Lxx/_Exx) handler.
 *
 *              This function executes at interrupt level.
 *
 ******************************************************************************/

u32
acpi_ev_gpe_dispatch(struct acpi_namespace_node *gpe_device,
                    struct acpi_gpe_event_info *gpe_event_info, u32 gpe_number)
{
        acpi_status status;
        u32 return_value;

        ACPI_FUNCTION_TRACE(ev_gpe_dispatch);

        /* Invoke global event handler if present */

        acpi_gpe_count++;
        if (acpi_gbl_global_event_handler) {
                acpi_gbl_global_event_handler(ACPI_EVENT_TYPE_GPE, gpe_device,
                                              gpe_number,
                                              acpi_gbl_global_event_handler_context);
        }

        /*
         * Always disable the GPE so that it does not keep firing before
         * any asynchronous activity completes (either from the execution
         * of a GPE method or an asynchronous GPE handler.)
         *
         * If there is no handler or method to run, just disable the
         * GPE and leave it disabled permanently to prevent further such
         * pointless events from firing.
         */
        status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_DISABLE);
        if (ACPI_FAILURE(status)) {
                ACPI_EXCEPTION((AE_INFO, status,
                                "Unable to disable GPE %02X", gpe_number));
                return_UINT32(ACPI_INTERRUPT_NOT_HANDLED);
        }

        /*
         * If edge-triggered, clear the GPE status bit now. Note that
         * level-triggered events are cleared after the GPE is serviced.
         */
        if ((gpe_event_info->flags & ACPI_GPE_XRUPT_TYPE_MASK) ==
            ACPI_GPE_EDGE_TRIGGERED) {
                status = acpi_hw_clear_gpe(gpe_event_info);
                if (ACPI_FAILURE(status)) {
                        ACPI_EXCEPTION((AE_INFO, status,
                                        "Unable to clear GPE %02X",
                                        gpe_number));
                        (void)acpi_hw_low_set_gpe(gpe_event_info,
                                                  ACPI_GPE_CONDITIONAL_ENABLE);
                        return_UINT32(ACPI_INTERRUPT_NOT_HANDLED);
                }
        }

        /*
         * Dispatch the GPE to either an installed handler or the control
         * method associated with this GPE (_Lxx or _Exx). If a handler
         * exists, we invoke it and do not attempt to run the method.
         * If there is neither a handler nor a method, leave the GPE
         * disabled.
         */
        switch (gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) {
        case ACPI_GPE_DISPATCH_HANDLER:

                /* Invoke the installed handler (at interrupt level) */

                return_value =
                    gpe_event_info->dispatch.handler->address(gpe_device,
                                                              gpe_number,
                                                              gpe_event_info->
                                                              dispatch.handler->
                                                              context);

                /* If requested, clear (if level-triggered) and reenable the GPE */

                if (return_value & ACPI_REENABLE_GPE) {
                        (void)acpi_ev_finish_gpe(gpe_event_info);
                }
                break;

        case ACPI_GPE_DISPATCH_METHOD:
        case ACPI_GPE_DISPATCH_NOTIFY:
                /*
                 * Execute the method associated with the GPE
                 * NOTE: Level-triggered GPEs are cleared after the method completes.
                 */
                status = acpi_os_execute(OSL_GPE_HANDLER,
                                         acpi_ev_asynch_execute_gpe_method,
                                         gpe_event_info);
                if (ACPI_FAILURE(status)) {
                        ACPI_EXCEPTION((AE_INFO, status,
                                        "Unable to queue handler for GPE %02X - event disabled",
                                        gpe_number));
                }
                break;

        default:
                /*
                 * No handler or method to run!
                 * 03/2010: This case should no longer be possible. We will not allow
                 * a GPE to be enabled if it has no handler or method.
                 */
                ACPI_ERROR((AE_INFO,
                            "No handler or method for GPE %02X, disabling event",
                            gpe_number));

                break;
        }

        return_UINT32(ACPI_INTERRUPT_HANDLED);
}

#endif                          /* !ACPI_REDUCED_HARDWARE */