ACPICA: New: acpi_read and acpi_write public interfaces

[linux-2.6/mini2440.git] / drivers / acpi / events / evgpeblk.c

/******************************************************************************
 *
 * Module Name: evgpeblk - GPE block creation and initialization.
 *
 *****************************************************************************/

/*
 * Copyright (C) 2000 - 2008, 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 <acpi/acevents.h>
#include <acpi/acnamesp.h>

#define _COMPONENT          ACPI_EVENTS
ACPI_MODULE_NAME("evgpeblk")

/* Local prototypes */
static acpi_status
acpi_ev_save_method_info(acpi_handle obj_handle,
                         u32 level, void *obj_desc, void **return_value);

static acpi_status
acpi_ev_match_prw_and_gpe(acpi_handle obj_handle,
                          u32 level, void *info, void **return_value);

static struct acpi_gpe_xrupt_info *acpi_ev_get_gpe_xrupt_block(u32
                                                               interrupt_number);

static acpi_status
acpi_ev_delete_gpe_xrupt(struct acpi_gpe_xrupt_info *gpe_xrupt);

static acpi_status
acpi_ev_install_gpe_block(struct acpi_gpe_block_info *gpe_block,
                          u32 interrupt_number);

static acpi_status
acpi_ev_create_gpe_info_blocks(struct acpi_gpe_block_info *gpe_block);

/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_valid_gpe_event
 *
 * PARAMETERS:  gpe_event_info              - Info for this GPE
 *
 * RETURN:      TRUE if the gpe_event is valid
 *
 * DESCRIPTION: Validate a GPE event. DO NOT CALL FROM INTERRUPT LEVEL.
 *              Should be called only when the GPE lists are semaphore locked
 *              and not subject to change.
 *
 ******************************************************************************/

u8 acpi_ev_valid_gpe_event(struct acpi_gpe_event_info *gpe_event_info)
{
        struct acpi_gpe_xrupt_info *gpe_xrupt_block;
        struct acpi_gpe_block_info *gpe_block;

        ACPI_FUNCTION_ENTRY();

        /* No need for spin lock since we are not changing any list elements */

        /* Walk the GPE interrupt levels */

        gpe_xrupt_block = acpi_gbl_gpe_xrupt_list_head;
        while (gpe_xrupt_block) {
                gpe_block = gpe_xrupt_block->gpe_block_list_head;

                /* Walk the GPE blocks on this interrupt level */

                while (gpe_block) {
                        if ((&gpe_block->event_info[0] <= gpe_event_info) &&
                            (&gpe_block->
                             event_info[((acpi_size) gpe_block->
                                         register_count) * 8] >
                             gpe_event_info)) {
                                return (TRUE);
                        }

                        gpe_block = gpe_block->next;
                }

                gpe_xrupt_block = gpe_xrupt_block->next;
        }

        return (FALSE);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_walk_gpe_list
 *
 * PARAMETERS:  gpe_walk_callback   - Routine called for each GPE block
 *              Context             - Value passed to callback
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Walk the GPE lists.
 *
 ******************************************************************************/

acpi_status
acpi_ev_walk_gpe_list(acpi_gpe_callback gpe_walk_callback, void *context)
{
        struct acpi_gpe_block_info *gpe_block;
        struct acpi_gpe_xrupt_info *gpe_xrupt_info;
        acpi_status status = AE_OK;
        acpi_cpu_flags flags;

        ACPI_FUNCTION_TRACE(ev_walk_gpe_list);

        flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);

        /* Walk the interrupt level descriptor list */

        gpe_xrupt_info = acpi_gbl_gpe_xrupt_list_head;
        while (gpe_xrupt_info) {

                /* Walk all Gpe Blocks attached to this interrupt level */

                gpe_block = gpe_xrupt_info->gpe_block_list_head;
                while (gpe_block) {

                        /* One callback per GPE block */

                        status =
                            gpe_walk_callback(gpe_xrupt_info, gpe_block,
                                              context);
                        if (ACPI_FAILURE(status)) {
                                if (status == AE_CTRL_END) {    /* Callback abort */
                                        status = AE_OK;
                                }
                                goto unlock_and_exit;
                        }

                        gpe_block = gpe_block->next;
                }

                gpe_xrupt_info = gpe_xrupt_info->next;
        }

      unlock_and_exit:
        acpi_os_release_lock(acpi_gbl_gpe_lock, flags);
        return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_delete_gpe_handlers
 *
 * PARAMETERS:  gpe_xrupt_info      - GPE Interrupt info
 *              gpe_block           - Gpe Block info
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Delete all Handler objects found in the GPE data structs.
 *              Used only prior to termination.
 *
 ******************************************************************************/

acpi_status
acpi_ev_delete_gpe_handlers(struct acpi_gpe_xrupt_info *gpe_xrupt_info,
                            struct acpi_gpe_block_info *gpe_block,
                            void *context)
{
        struct acpi_gpe_event_info *gpe_event_info;
        u32 i;
        u32 j;

        ACPI_FUNCTION_TRACE(ev_delete_gpe_handlers);

        /* Examine each GPE Register within the block */

        for (i = 0; i < gpe_block->register_count; i++) {

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

                for (j = 0; j < ACPI_GPE_REGISTER_WIDTH; j++) {
                        gpe_event_info =
                            &gpe_block->
                            event_info[((acpi_size) i *
                                        ACPI_GPE_REGISTER_WIDTH) + j];

                        if ((gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) ==
                            ACPI_GPE_DISPATCH_HANDLER) {
                                ACPI_FREE(gpe_event_info->dispatch.handler);
                                gpe_event_info->dispatch.handler = NULL;
                                gpe_event_info->flags &=
                                    ~ACPI_GPE_DISPATCH_MASK;
                        }
                }
        }

        return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_save_method_info
 *
 * PARAMETERS:  Callback from walk_namespace
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Called from acpi_walk_namespace. Expects each object to be a
 *              control method under the _GPE portion of the namespace.
 *              Extract the name and GPE type from the object, saving this
 *              information for quick lookup during GPE dispatch
 *
 *              The name of each GPE control method is of the form:
 *              "_Lxx" or "_Exx"
 *              Where:
 *                  L      - means that the GPE is level triggered
 *                  E      - means that the GPE is edge triggered
 *                  xx     - is the GPE number [in HEX]
 *
 ******************************************************************************/

static acpi_status
acpi_ev_save_method_info(acpi_handle obj_handle,
                         u32 level, void *obj_desc, void **return_value)
{
        struct acpi_gpe_block_info *gpe_block = (void *)obj_desc;
        struct acpi_gpe_event_info *gpe_event_info;
        u32 gpe_number;
        char name[ACPI_NAME_SIZE + 1];
        u8 type;
        acpi_status status;

        ACPI_FUNCTION_TRACE(ev_save_method_info);

        /*
         * _Lxx and _Exx GPE method support
         *
         * 1) Extract the name from the object and convert to a string
         */
        ACPI_MOVE_32_TO_32(name,
                           &((struct acpi_namespace_node *)obj_handle)->name.
                           integer);
        name[ACPI_NAME_SIZE] = 0;

        /*
         * 2) Edge/Level determination is based on the 2nd character
         *    of the method name
         *
         * NOTE: Default GPE type is RUNTIME. May be changed later to WAKE
         * if a _PRW object is found that points to this GPE.
         */
        switch (name[1]) {
        case 'L':
                type = ACPI_GPE_LEVEL_TRIGGERED;
                break;

        case 'E':
                type = ACPI_GPE_EDGE_TRIGGERED;
                break;

        default:
                /* Unknown method type, just ignore it! */

                ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
                                  "Ignoring unknown GPE method type: %s (name not of form _Lxx or _Exx)",
                                  name));
                return_ACPI_STATUS(AE_OK);
        }

        /* Convert the last two characters of the name to the GPE Number */

        gpe_number = ACPI_STRTOUL(&name[2], NULL, 16);
        if (gpe_number == ACPI_UINT32_MAX) {

                /* Conversion failed; invalid method, just ignore it */

                ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
                                  "Could not extract GPE number from name: %s (name is not of form _Lxx or _Exx)",
                                  name));
                return_ACPI_STATUS(AE_OK);
        }

        /* Ensure that we have a valid GPE number for this GPE block */

        if ((gpe_number < gpe_block->block_base_number) ||
            (gpe_number >=
             (gpe_block->block_base_number +
              (gpe_block->register_count * 8)))) {
                /*
                 * Not valid for this GPE block, just ignore it. However, it may be
                 * valid for a different GPE block, since GPE0 and GPE1 methods both
                 * appear under \_GPE.
                 */
                return_ACPI_STATUS(AE_OK);
        }

        /*
         * Now we can add this information to the gpe_event_info block for use
         * during dispatch of this GPE. Default type is RUNTIME, although this may
         * change when the _PRW methods are executed later.
         */
        gpe_event_info =
            &gpe_block->event_info[gpe_number - gpe_block->block_base_number];

        gpe_event_info->flags = (u8)
            (type | ACPI_GPE_DISPATCH_METHOD | ACPI_GPE_TYPE_RUNTIME);

        gpe_event_info->dispatch.method_node =
            (struct acpi_namespace_node *)obj_handle;

        /* Update enable mask, but don't enable the HW GPE as of yet */

        status = acpi_ev_enable_gpe(gpe_event_info, FALSE);

        ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
                          "Registered GPE method %s as GPE number 0x%.2X\n",
                          name, gpe_number));
        return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_match_prw_and_gpe
 *
 * PARAMETERS:  Callback from walk_namespace
 *
 * RETURN:      Status. NOTE: We ignore errors so that the _PRW walk is
 *              not aborted on a single _PRW failure.
 *
 * DESCRIPTION: Called from acpi_walk_namespace. Expects each object to be a
 *              Device. Run the _PRW method. If present, extract the GPE
 *              number and mark the GPE as a WAKE GPE.
 *
 ******************************************************************************/

static acpi_status
acpi_ev_match_prw_and_gpe(acpi_handle obj_handle,
                          u32 level, void *info, void **return_value)
{
        struct acpi_gpe_walk_info *gpe_info = (void *)info;
        struct acpi_namespace_node *gpe_device;
        struct acpi_gpe_block_info *gpe_block;
        struct acpi_namespace_node *target_gpe_device;
        struct acpi_gpe_event_info *gpe_event_info;
        union acpi_operand_object *pkg_desc;
        union acpi_operand_object *obj_desc;
        u32 gpe_number;
        acpi_status status;

        ACPI_FUNCTION_TRACE(ev_match_prw_and_gpe);

        /* Check for a _PRW method under this device */

        status = acpi_ut_evaluate_object(obj_handle, METHOD_NAME__PRW,
                                         ACPI_BTYPE_PACKAGE, &pkg_desc);
        if (ACPI_FAILURE(status)) {

                /* Ignore all errors from _PRW, we don't want to abort the subsystem */

                return_ACPI_STATUS(AE_OK);
        }

        /* The returned _PRW package must have at least two elements */

        if (pkg_desc->package.count < 2) {
                goto cleanup;
        }

        /* Extract pointers from the input context */

        gpe_device = gpe_info->gpe_device;
        gpe_block = gpe_info->gpe_block;

        /*
         * The _PRW object must return a package, we are only interested in the
         * first element
         */
        obj_desc = pkg_desc->package.elements[0];

        if (ACPI_GET_OBJECT_TYPE(obj_desc) == ACPI_TYPE_INTEGER) {

                /* Use FADT-defined GPE device (from definition of _PRW) */

                target_gpe_device = acpi_gbl_fadt_gpe_device;

                /* Integer is the GPE number in the FADT described GPE blocks */

                gpe_number = (u32) obj_desc->integer.value;
        } else if (ACPI_GET_OBJECT_TYPE(obj_desc) == ACPI_TYPE_PACKAGE) {

                /* Package contains a GPE reference and GPE number within a GPE block */

                if ((obj_desc->package.count < 2) ||
                    (ACPI_GET_OBJECT_TYPE(obj_desc->package.elements[0]) !=
                     ACPI_TYPE_LOCAL_REFERENCE)
                    || (ACPI_GET_OBJECT_TYPE(obj_desc->package.elements[1]) !=
                        ACPI_TYPE_INTEGER)) {
                        goto cleanup;
                }

                /* Get GPE block reference and decode */

                target_gpe_device =
                    obj_desc->package.elements[0]->reference.node;
                gpe_number = (u32) obj_desc->package.elements[1]->integer.value;
        } else {
                /* Unknown type, just ignore it */

                goto cleanup;
        }

        /*
         * Is this GPE within this block?
         *
         * TRUE if and only if these conditions are true:
         *     1) The GPE devices match.
         *     2) The GPE index(number) is within the range of the Gpe Block
         *          associated with the GPE device.
         */
        if ((gpe_device == target_gpe_device) &&
            (gpe_number >= gpe_block->block_base_number) &&
            (gpe_number <
             gpe_block->block_base_number + (gpe_block->register_count * 8))) {
                gpe_event_info =
                    &gpe_block->event_info[gpe_number -
                                           gpe_block->block_base_number];

                /* Mark GPE for WAKE-ONLY but WAKE_DISABLED */

                gpe_event_info->flags &=
                    ~(ACPI_GPE_WAKE_ENABLED | ACPI_GPE_RUN_ENABLED);

                status =
                    acpi_ev_set_gpe_type(gpe_event_info, ACPI_GPE_TYPE_WAKE);
                if (ACPI_FAILURE(status)) {
                        goto cleanup;
                }

                status =
                    acpi_ev_update_gpe_enable_masks(gpe_event_info,
                                                    ACPI_GPE_DISABLE);
        }

      cleanup:
        acpi_ut_remove_reference(pkg_desc);
        return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_get_gpe_xrupt_block
 *
 * PARAMETERS:  interrupt_number     - Interrupt for a GPE block
 *
 * RETURN:      A GPE interrupt block
 *
 * DESCRIPTION: Get or Create a GPE interrupt block. There is one interrupt
 *              block per unique interrupt level used for GPEs. Should be
 *              called only when the GPE lists are semaphore locked and not
 *              subject to change.
 *
 ******************************************************************************/

static struct acpi_gpe_xrupt_info *acpi_ev_get_gpe_xrupt_block(u32
                                                               interrupt_number)
{
        struct acpi_gpe_xrupt_info *next_gpe_xrupt;
        struct acpi_gpe_xrupt_info *gpe_xrupt;
        acpi_status status;
        acpi_cpu_flags flags;

        ACPI_FUNCTION_TRACE(ev_get_gpe_xrupt_block);

        /* No need for lock since we are not changing any list elements here */

        next_gpe_xrupt = acpi_gbl_gpe_xrupt_list_head;
        while (next_gpe_xrupt) {
                if (next_gpe_xrupt->interrupt_number == interrupt_number) {
                        return_PTR(next_gpe_xrupt);
                }

                next_gpe_xrupt = next_gpe_xrupt->next;
        }

        /* Not found, must allocate a new xrupt descriptor */

        gpe_xrupt = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_gpe_xrupt_info));
        if (!gpe_xrupt) {
                return_PTR(NULL);
        }

        gpe_xrupt->interrupt_number = interrupt_number;

        /* Install new interrupt descriptor with spin lock */

        flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);
        if (acpi_gbl_gpe_xrupt_list_head) {
                next_gpe_xrupt = acpi_gbl_gpe_xrupt_list_head;
                while (next_gpe_xrupt->next) {
                        next_gpe_xrupt = next_gpe_xrupt->next;
                }

                next_gpe_xrupt->next = gpe_xrupt;
                gpe_xrupt->previous = next_gpe_xrupt;
        } else {
                acpi_gbl_gpe_xrupt_list_head = gpe_xrupt;
        }
        acpi_os_release_lock(acpi_gbl_gpe_lock, flags);

        /* Install new interrupt handler if not SCI_INT */

        if (interrupt_number != acpi_gbl_FADT.sci_interrupt) {
                status = acpi_os_install_interrupt_handler(interrupt_number,
                                                           acpi_ev_gpe_xrupt_handler,
                                                           gpe_xrupt);
                if (ACPI_FAILURE(status)) {
                        ACPI_ERROR((AE_INFO,
                                    "Could not install GPE interrupt handler at level 0x%X",
                                    interrupt_number));
                        return_PTR(NULL);
                }
        }

        return_PTR(gpe_xrupt);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_delete_gpe_xrupt
 *
 * PARAMETERS:  gpe_xrupt       - A GPE interrupt info block
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Remove and free a gpe_xrupt block. Remove an associated
 *              interrupt handler if not the SCI interrupt.
 *
 ******************************************************************************/

static acpi_status
acpi_ev_delete_gpe_xrupt(struct acpi_gpe_xrupt_info *gpe_xrupt)
{
        acpi_status status;
        acpi_cpu_flags flags;

        ACPI_FUNCTION_TRACE(ev_delete_gpe_xrupt);

        /* We never want to remove the SCI interrupt handler */

        if (gpe_xrupt->interrupt_number == acpi_gbl_FADT.sci_interrupt) {
                gpe_xrupt->gpe_block_list_head = NULL;
                return_ACPI_STATUS(AE_OK);
        }

        /* Disable this interrupt */

        status =
            acpi_os_remove_interrupt_handler(gpe_xrupt->interrupt_number,
                                             acpi_ev_gpe_xrupt_handler);
        if (ACPI_FAILURE(status)) {
                return_ACPI_STATUS(status);
        }

        /* Unlink the interrupt block with lock */

        flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);
        if (gpe_xrupt->previous) {
                gpe_xrupt->previous->next = gpe_xrupt->next;
        } else {
                /* No previous, update list head */

                acpi_gbl_gpe_xrupt_list_head = gpe_xrupt->next;
        }

        if (gpe_xrupt->next) {
                gpe_xrupt->next->previous = gpe_xrupt->previous;
        }
        acpi_os_release_lock(acpi_gbl_gpe_lock, flags);

        /* Free the block */

        ACPI_FREE(gpe_xrupt);
        return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_install_gpe_block
 *
 * PARAMETERS:  gpe_block               - New GPE block
 *              interrupt_number        - Xrupt to be associated with this
 *                                        GPE block
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Install new GPE block with mutex support
 *
 ******************************************************************************/

static acpi_status
acpi_ev_install_gpe_block(struct acpi_gpe_block_info *gpe_block,
                          u32 interrupt_number)
{
        struct acpi_gpe_block_info *next_gpe_block;
        struct acpi_gpe_xrupt_info *gpe_xrupt_block;
        acpi_status status;
        acpi_cpu_flags flags;

        ACPI_FUNCTION_TRACE(ev_install_gpe_block);

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

        gpe_xrupt_block = acpi_ev_get_gpe_xrupt_block(interrupt_number);
        if (!gpe_xrupt_block) {
                status = AE_NO_MEMORY;
                goto unlock_and_exit;
        }

        /* Install the new block at the end of the list with lock */

        flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);
        if (gpe_xrupt_block->gpe_block_list_head) {
                next_gpe_block = gpe_xrupt_block->gpe_block_list_head;
                while (next_gpe_block->next) {
                        next_gpe_block = next_gpe_block->next;
                }

                next_gpe_block->next = gpe_block;
                gpe_block->previous = next_gpe_block;
        } else {
                gpe_xrupt_block->gpe_block_list_head = gpe_block;
        }

        gpe_block->xrupt_block = gpe_xrupt_block;
        acpi_os_release_lock(acpi_gbl_gpe_lock, flags);

      unlock_and_exit:
        status = acpi_ut_release_mutex(ACPI_MTX_EVENTS);
        return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_delete_gpe_block
 *
 * PARAMETERS:  gpe_block           - Existing GPE block
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Remove a GPE block
 *
 ******************************************************************************/

acpi_status acpi_ev_delete_gpe_block(struct acpi_gpe_block_info *gpe_block)
{
        acpi_status status;
        acpi_cpu_flags flags;

        ACPI_FUNCTION_TRACE(ev_install_gpe_block);

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

        /* Disable all GPEs in this block */

        status =
            acpi_hw_disable_gpe_block(gpe_block->xrupt_block, gpe_block, NULL);

        if (!gpe_block->previous && !gpe_block->next) {

                /* This is the last gpe_block on this interrupt */

                status = acpi_ev_delete_gpe_xrupt(gpe_block->xrupt_block);
                if (ACPI_FAILURE(status)) {
                        goto unlock_and_exit;
                }
        } else {
                /* Remove the block on this interrupt with lock */

                flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);
                if (gpe_block->previous) {
                        gpe_block->previous->next = gpe_block->next;
                } else {
                        gpe_block->xrupt_block->gpe_block_list_head =
                            gpe_block->next;
                }

                if (gpe_block->next) {
                        gpe_block->next->previous = gpe_block->previous;
                }
                acpi_os_release_lock(acpi_gbl_gpe_lock, flags);
        }

        acpi_current_gpe_count -=
            gpe_block->register_count * ACPI_GPE_REGISTER_WIDTH;

        /* Free the gpe_block */

        ACPI_FREE(gpe_block->register_info);
        ACPI_FREE(gpe_block->event_info);
        ACPI_FREE(gpe_block);

      unlock_and_exit:
        status = acpi_ut_release_mutex(ACPI_MTX_EVENTS);
        return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_create_gpe_info_blocks
 *
 * PARAMETERS:  gpe_block   - New GPE block
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Create the register_info and event_info blocks for this GPE block
 *
 ******************************************************************************/

static acpi_status
acpi_ev_create_gpe_info_blocks(struct acpi_gpe_block_info *gpe_block)
{
        struct acpi_gpe_register_info *gpe_register_info = NULL;
        struct acpi_gpe_event_info *gpe_event_info = NULL;
        struct acpi_gpe_event_info *this_event;
        struct acpi_gpe_register_info *this_register;
        u32 i;
        u32 j;
        acpi_status status;

        ACPI_FUNCTION_TRACE(ev_create_gpe_info_blocks);

        /* Allocate the GPE register information block */

        gpe_register_info = ACPI_ALLOCATE_ZEROED((acpi_size) gpe_block->
                                                 register_count *
                                                 sizeof(struct
                                                        acpi_gpe_register_info));
        if (!gpe_register_info) {
                ACPI_ERROR((AE_INFO,
                            "Could not allocate the GpeRegisterInfo table"));
                return_ACPI_STATUS(AE_NO_MEMORY);
        }

        /*
         * Allocate the GPE event_info block. There are eight distinct GPEs
         * per register. Initialization to zeros is sufficient.
         */
        gpe_event_info = ACPI_ALLOCATE_ZEROED(((acpi_size) gpe_block->
                                               register_count *
                                               ACPI_GPE_REGISTER_WIDTH) *
                                              sizeof(struct
                                                     acpi_gpe_event_info));
        if (!gpe_event_info) {
                ACPI_ERROR((AE_INFO,
                            "Could not allocate the GpeEventInfo table"));
                status = AE_NO_MEMORY;
                goto error_exit;
        }

        /* Save the new Info arrays in the GPE block */

        gpe_block->register_info = gpe_register_info;
        gpe_block->event_info = gpe_event_info;

        /*
         * Initialize the GPE Register and Event structures. A goal of these
         * tables is to hide the fact that there are two separate GPE register
         * sets in a given GPE hardware block, the status registers occupy the
         * first half, and the enable registers occupy the second half.
         */
        this_register = gpe_register_info;
        this_event = gpe_event_info;

        for (i = 0; i < gpe_block->register_count; i++) {

                /* Init the register_info for this GPE register (8 GPEs) */

                this_register->base_gpe_number =
                    (u8) (gpe_block->block_base_number +
                          (i * ACPI_GPE_REGISTER_WIDTH));

                this_register->status_address.address =
                    gpe_block->block_address.address + i;

                this_register->enable_address.address =
                    gpe_block->block_address.address + i +
                    gpe_block->register_count;

                this_register->status_address.space_id =
                    gpe_block->block_address.space_id;
                this_register->enable_address.space_id =
                    gpe_block->block_address.space_id;
                this_register->status_address.bit_width =
                    ACPI_GPE_REGISTER_WIDTH;
                this_register->enable_address.bit_width =
                    ACPI_GPE_REGISTER_WIDTH;
                this_register->status_address.bit_offset = 0;
                this_register->enable_address.bit_offset = 0;

                /* Init the event_info for each GPE within this register */

                for (j = 0; j < ACPI_GPE_REGISTER_WIDTH; j++) {
                        this_event->gpe_number =
                            (u8) (this_register->base_gpe_number + j);
                        this_event->register_info = this_register;
                        this_event++;
                }

                /* Disable all GPEs within this register */

                status = acpi_write(0x00, &this_register->enable_address);
                if (ACPI_FAILURE(status)) {
                        goto error_exit;
                }

                /* Clear any pending GPE events within this register */

                status = acpi_write(0xFF, &this_register->status_address);
                if (ACPI_FAILURE(status)) {
                        goto error_exit;
                }

                this_register++;
        }

        return_ACPI_STATUS(AE_OK);

      error_exit:
        if (gpe_register_info) {
                ACPI_FREE(gpe_register_info);
        }
        if (gpe_event_info) {
                ACPI_FREE(gpe_event_info);
        }

        return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_create_gpe_block
 *
 * PARAMETERS:  gpe_device          - Handle to the parent GPE block
 *              gpe_block_address   - Address and space_iD
 *              register_count      - Number of GPE register pairs in the block
 *              gpe_block_base_number - Starting GPE number for the block
 *              interrupt_number    - H/W interrupt for the block
 *              return_gpe_block    - Where the new block descriptor is returned
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Create and Install a block of GPE registers. All GPEs within
 *              the block are disabled at exit.
 *              Note: Assumes namespace is locked.
 *
 ******************************************************************************/

acpi_status
acpi_ev_create_gpe_block(struct acpi_namespace_node *gpe_device,
                         struct acpi_generic_address *gpe_block_address,
                         u32 register_count,
                         u8 gpe_block_base_number,
                         u32 interrupt_number,
                         struct acpi_gpe_block_info **return_gpe_block)
{
        acpi_status status;
        struct acpi_gpe_block_info *gpe_block;

        ACPI_FUNCTION_TRACE(ev_create_gpe_block);

        if (!register_count) {
                return_ACPI_STATUS(AE_OK);
        }

        /* Allocate a new GPE block */

        gpe_block = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_gpe_block_info));
        if (!gpe_block) {
                return_ACPI_STATUS(AE_NO_MEMORY);
        }

        /* Initialize the new GPE block */

        gpe_block->node = gpe_device;
        gpe_block->register_count = register_count;
        gpe_block->block_base_number = gpe_block_base_number;

        ACPI_MEMCPY(&gpe_block->block_address, gpe_block_address,
                    sizeof(struct acpi_generic_address));

        /*
         * Create the register_info and event_info sub-structures
         * Note: disables and clears all GPEs in the block
         */
        status = acpi_ev_create_gpe_info_blocks(gpe_block);
        if (ACPI_FAILURE(status)) {
                ACPI_FREE(gpe_block);
                return_ACPI_STATUS(status);
        }

        /* Install the new block in the global lists */

        status = acpi_ev_install_gpe_block(gpe_block, interrupt_number);
        if (ACPI_FAILURE(status)) {
                ACPI_FREE(gpe_block);
                return_ACPI_STATUS(status);
        }

        /* Find all GPE methods (_Lxx, _Exx) for this block */

        status = acpi_ns_walk_namespace(ACPI_TYPE_METHOD, gpe_device,
                                        ACPI_UINT32_MAX, ACPI_NS_WALK_NO_UNLOCK,
                                        acpi_ev_save_method_info, gpe_block,
                                        NULL);

        /* Return the new block */

        if (return_gpe_block) {
                (*return_gpe_block) = gpe_block;
        }

        ACPI_DEBUG_PRINT((ACPI_DB_INIT,
                          "GPE %02X to %02X [%4.4s] %u regs on int 0x%X\n",
                          (u32) gpe_block->block_base_number,
                          (u32) (gpe_block->block_base_number +
                                 ((gpe_block->register_count *
                                   ACPI_GPE_REGISTER_WIDTH) - 1)),
                          gpe_device->name.ascii, gpe_block->register_count,
                          interrupt_number));

        /* Update global count of currently available GPEs */

        acpi_current_gpe_count += register_count * ACPI_GPE_REGISTER_WIDTH;
        return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_initialize_gpe_block
 *
 * PARAMETERS:  gpe_device          - Handle to the parent GPE block
 *              gpe_block           - Gpe Block info
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Initialize and enable a GPE block. First find and run any
 *              _PRT methods associated with the block, then enable the
 *              appropriate GPEs.
 *              Note: Assumes namespace is locked.
 *
 ******************************************************************************/

acpi_status
acpi_ev_initialize_gpe_block(struct acpi_namespace_node *gpe_device,
                             struct acpi_gpe_block_info *gpe_block)
{
        acpi_status status;
        struct acpi_gpe_event_info *gpe_event_info;
        struct acpi_gpe_walk_info gpe_info;
        u32 wake_gpe_count;
        u32 gpe_enabled_count;
        u32 i;
        u32 j;

        ACPI_FUNCTION_TRACE(ev_initialize_gpe_block);

        /* Ignore a null GPE block (e.g., if no GPE block 1 exists) */

        if (!gpe_block) {
                return_ACPI_STATUS(AE_OK);
        }

        /*
         * Runtime option: Should wake GPEs be enabled at runtime?  The default
         * is no, they should only be enabled just as the machine goes to sleep.
         */
        if (acpi_gbl_leave_wake_gpes_disabled) {
                /*
                 * Differentiate runtime vs wake GPEs, via the _PRW control methods.
                 * Each GPE that has one or more _PRWs that reference it is by
                 * definition a wake GPE and will not be enabled while the machine
                 * is running.
                 */
                gpe_info.gpe_block = gpe_block;
                gpe_info.gpe_device = gpe_device;

                status =
                    acpi_ns_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
                                           ACPI_UINT32_MAX, ACPI_NS_WALK_UNLOCK,
                                           acpi_ev_match_prw_and_gpe, &gpe_info,
                                           NULL);
        }

        /*
         * Enable all GPEs in this block that have these attributes:
         * 1) are "runtime" or "run/wake" GPEs, and
         * 2) have a corresponding _Lxx or _Exx method
         *
         * Any other GPEs within this block must be enabled via the acpi_enable_gpe()
         * external interface.
         */
        wake_gpe_count = 0;
        gpe_enabled_count = 0;

        for (i = 0; i < gpe_block->register_count; i++) {
                for (j = 0; j < 8; j++) {

                        /* Get the info block for this particular GPE */

                        gpe_event_info =
                            &gpe_block->
                            event_info[((acpi_size) i *
                                        ACPI_GPE_REGISTER_WIDTH) + j];

                        if (((gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) ==
                             ACPI_GPE_DISPATCH_METHOD)
                            && (gpe_event_info->flags & ACPI_GPE_TYPE_RUNTIME)) {
                                gpe_enabled_count++;
                        }

                        if (gpe_event_info->flags & ACPI_GPE_TYPE_WAKE) {
                                wake_gpe_count++;
                        }
                }
        }

        ACPI_DEBUG_PRINT((ACPI_DB_INIT,
                          "Found %u Wake, Enabled %u Runtime GPEs in this block\n",
                          wake_gpe_count, gpe_enabled_count));

        /* Enable all valid runtime GPEs found above */

        status = acpi_hw_enable_runtime_gpe_block(NULL, gpe_block, NULL);
        if (ACPI_FAILURE(status)) {
                ACPI_ERROR((AE_INFO, "Could not enable GPEs in GpeBlock %p",
                            gpe_block));
        }

        return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ev_gpe_initialize
 *
 * PARAMETERS:  None
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Initialize the GPE data structures
 *
 ******************************************************************************/

acpi_status acpi_ev_gpe_initialize(void)
{
        u32 register_count0 = 0;
        u32 register_count1 = 0;
        u32 gpe_number_max = 0;
        acpi_status status;

        ACPI_FUNCTION_TRACE(ev_gpe_initialize);

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

        /*
         * Initialize the GPE Block(s) defined in the FADT
         *
         * Why the GPE register block lengths are divided by 2:  From the ACPI Spec,
         * section "General-Purpose Event Registers", we have:
         *
         * "Each register block contains two registers of equal length
         *  GPEx_STS and GPEx_EN (where x is 0 or 1). The length of the
         *  GPE0_STS and GPE0_EN registers is equal to half the GPE0_LEN
         *  The length of the GPE1_STS and GPE1_EN registers is equal to
         *  half the GPE1_LEN. If a generic register block is not supported
         *  then its respective block pointer and block length values in the
         *  FADT table contain zeros. The GPE0_LEN and GPE1_LEN do not need
         *  to be the same size."
         */

        /*
         * Determine the maximum GPE number for this machine.
         *
         * Note: both GPE0 and GPE1 are optional, and either can exist without
         * the other.
         *
         * If EITHER the register length OR the block address are zero, then that
         * particular block is not supported.
         */
        if (acpi_gbl_FADT.gpe0_block_length &&
            acpi_gbl_FADT.xgpe0_block.address) {

                /* GPE block 0 exists (has both length and address > 0) */

                register_count0 = (u16) (acpi_gbl_FADT.gpe0_block_length / 2);

                gpe_number_max =
                    (register_count0 * ACPI_GPE_REGISTER_WIDTH) - 1;

                /* Install GPE Block 0 */

                status = acpi_ev_create_gpe_block(acpi_gbl_fadt_gpe_device,
                                                  &acpi_gbl_FADT.xgpe0_block,
                                                  register_count0, 0,
                                                  acpi_gbl_FADT.sci_interrupt,
                                                  &acpi_gbl_gpe_fadt_blocks[0]);

                if (ACPI_FAILURE(status)) {
                        ACPI_EXCEPTION((AE_INFO, status,
                                        "Could not create GPE Block 0"));
                }
        }

        if (acpi_gbl_FADT.gpe1_block_length &&
            acpi_gbl_FADT.xgpe1_block.address) {

                /* GPE block 1 exists (has both length and address > 0) */

                register_count1 = (u16) (acpi_gbl_FADT.gpe1_block_length / 2);

                /* Check for GPE0/GPE1 overlap (if both banks exist) */

                if ((register_count0) &&
                    (gpe_number_max >= acpi_gbl_FADT.gpe1_base)) {
                        ACPI_ERROR((AE_INFO,
                                    "GPE0 block (GPE 0 to %d) overlaps the GPE1 block (GPE %d to %d) - Ignoring GPE1",
                                    gpe_number_max, acpi_gbl_FADT.gpe1_base,
                                    acpi_gbl_FADT.gpe1_base +
                                    ((register_count1 *
                                      ACPI_GPE_REGISTER_WIDTH) - 1)));

                        /* Ignore GPE1 block by setting the register count to zero */

                        register_count1 = 0;
                } else {
                        /* Install GPE Block 1 */

                        status =
                            acpi_ev_create_gpe_block(acpi_gbl_fadt_gpe_device,
                                                     &acpi_gbl_FADT.xgpe1_block,
                                                     register_count1,
                                                     acpi_gbl_FADT.gpe1_base,
                                                     acpi_gbl_FADT.
                                                     sci_interrupt,
                                                     &acpi_gbl_gpe_fadt_blocks
                                                     [1]);

                        if (ACPI_FAILURE(status)) {
                                ACPI_EXCEPTION((AE_INFO, status,
                                                "Could not create GPE Block 1"));
                        }

                        /*
                         * GPE0 and GPE1 do not have to be contiguous in the GPE number
                         * space. However, GPE0 always starts at GPE number zero.
                         */
                        gpe_number_max = acpi_gbl_FADT.gpe1_base +
                            ((register_count1 * ACPI_GPE_REGISTER_WIDTH) - 1);
                }
        }

        /* Exit if there are no GPE registers */

        if ((register_count0 + register_count1) == 0) {

                /* GPEs are not required by ACPI, this is OK */

                ACPI_DEBUG_PRINT((ACPI_DB_INIT,
                                  "There are no GPE blocks defined in the FADT\n"));
                status = AE_OK;
                goto cleanup;
        }

        /* Check for Max GPE number out-of-range */

        if (gpe_number_max > ACPI_GPE_MAX) {
                ACPI_ERROR((AE_INFO,
                            "Maximum GPE number from FADT is too large: 0x%X",
                            gpe_number_max));
                status = AE_BAD_VALUE;
                goto cleanup;
        }

      cleanup:
        (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
        return_ACPI_STATUS(AE_OK);
}