ACPICA 20050617-0624 from Bob Moore <robert.moore@intel.com>

[firewire-audio.git] / drivers / acpi / events / evgpeblk.c

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

/*
 * Copyright (C) 2000 - 2005, R. Byron Moore
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    substantially similar to the "NO WARRANTY" disclaimer below
 *    ("Disclaimer") and any redistribution must be conditioned upon
 *    including a substantially similar Disclaimer requirement for further
 *    binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * NO WARRANTY
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 */

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

#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
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Walk the GPE lists.
 *
 ******************************************************************************/

acpi_status
acpi_ev_walk_gpe_list (
        ACPI_GPE_CALLBACK       gpe_walk_callback)
{
        struct acpi_gpe_block_info      *gpe_block;
        struct acpi_gpe_xrupt_info      *gpe_xrupt_info;
        acpi_status                     status = AE_OK;
        u32                             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);
                        if (ACPI_FAILURE (status)) {
                                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)
{
        struct acpi_gpe_event_info      *gpe_event_info;
        acpi_native_uint                i;
        acpi_native_uint                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[(i * ACPI_GPE_REGISTER_WIDTH) + j];

                        if ((gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) ==
                                        ACPI_GPE_DISPATCH_HANDLER) {
                                ACPI_MEM_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_ERROR,
                        "Unknown GPE method type: %s (name not of form _Lxx or _Exx)\n",
                        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_ERROR,
                        "Could not extract GPE number from name: %s (name is not of form _Lxx or _Exx)\n",
                        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 iff 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;
        u32                             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_MEM_CALLOCATE (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_int) {
                status = acpi_os_install_interrupt_handler (interrupt_number,
                                 acpi_ev_gpe_xrupt_handler, gpe_xrupt);
                if (ACPI_FAILURE (status)) {
                        ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
                                "Could not install GPE interrupt handler at level 0x%X\n",
                                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;
        u32                             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_int) {
                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;
        }

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

        /* Free the block */

        ACPI_MEM_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;
        u32                             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;
        u32                             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);

        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);
        }

        /* Free the gpe_block */

        ACPI_MEM_FREE (gpe_block->register_info);
        ACPI_MEM_FREE (gpe_block->event_info);
        ACPI_MEM_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;
        acpi_native_uint                i;
        acpi_native_uint                j;
        acpi_status                     status;


        ACPI_FUNCTION_TRACE ("ev_create_gpe_info_blocks");


        /* Allocate the GPE register information block */

        gpe_register_info = ACPI_MEM_CALLOCATE (
                          (acpi_size) gpe_block->register_count *
                          sizeof (struct acpi_gpe_register_info));
        if (!gpe_register_info) {
                ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
                        "Could not allocate the gpe_register_info table\n"));
                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_MEM_CALLOCATE (
                           ((acpi_size) gpe_block->register_count *
                           ACPI_GPE_REGISTER_WIDTH) *
                           sizeof (struct acpi_gpe_event_info));
        if (!gpe_event_info) {
                ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
                        "Could not allocate the gpe_event_info table\n"));
                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));

                ACPI_STORE_ADDRESS (this_register->status_address.address,
                                 (gpe_block->block_address.address
                                 + i));

                ACPI_STORE_ADDRESS (this_register->enable_address.address,
                                 (gpe_block->block_address.address
                                 + i
                                 + gpe_block->register_count));

                this_register->status_address.address_space_id = gpe_block->block_address.address_space_id;
                this_register->enable_address.address_space_id = gpe_block->block_address.address_space_id;
                this_register->status_address.register_bit_width = ACPI_GPE_REGISTER_WIDTH;
                this_register->enable_address.register_bit_width = ACPI_GPE_REGISTER_WIDTH;
                this_register->status_address.register_bit_offset = ACPI_GPE_REGISTER_WIDTH;
                this_register->enable_address.register_bit_offset = ACPI_GPE_REGISTER_WIDTH;

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

                for (j = 0; j < ACPI_GPE_REGISTER_WIDTH; j++) {
                        this_event->register_bit = acpi_gbl_decode_to8bit[j];
                        this_event->register_info = this_register;
                        this_event++;
                }

                /*
                 * Clear the status/enable registers.  Note that status registers
                 * are cleared by writing a '1', while enable registers are cleared
                 * by writing a '0'.
                 */
                status = acpi_hw_low_level_write (ACPI_GPE_REGISTER_WIDTH, 0x00,
                                 &this_register->enable_address);
                if (ACPI_FAILURE (status)) {
                        goto error_exit;
                }

                status = acpi_hw_low_level_write (ACPI_GPE_REGISTER_WIDTH, 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_MEM_FREE (gpe_register_info);
        }
        if (gpe_event_info) {
                ACPI_MEM_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
 *
 ******************************************************************************/

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)
{
        struct acpi_gpe_block_info      *gpe_block;
        struct acpi_gpe_event_info      *gpe_event_info;
        acpi_native_uint                i;
        acpi_native_uint                j;
        u32                             wake_gpe_count;
        u32                             gpe_enabled_count;
        acpi_status                     status;
        struct acpi_gpe_walk_info       gpe_info;


        ACPI_FUNCTION_TRACE ("ev_create_gpe_block");


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

        /* Allocate a new GPE block */

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

        /* Initialize the new GPE block */

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

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

        /* Create the register_info and event_info sub-structures */

        status = acpi_ev_create_gpe_info_blocks (gpe_block);
        if (ACPI_FAILURE (status)) {
                ACPI_MEM_FREE (gpe_block);
                return_ACPI_STATUS (status);
        }

        /* Install the new block in the global list(s) */

        status = acpi_ev_install_gpe_block (gpe_block, interrupt_number);
        if (ACPI_FAILURE (status)) {
                ACPI_MEM_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);

        /*
         * 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 are 1) "runtime" or "run/wake" GPEs,
         * and 2) have a corresponding _Lxx or _Exx method.  All other GPEs 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[(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++;
                        }
                }
        }

        /* Dump info about this 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));

        /* Enable all valid GPEs found above */

        status = acpi_hw_enable_runtime_gpe_block (NULL, gpe_block);

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

        /* Return the new block */

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

        return_ACPI_STATUS (AE_OK);
}


/*******************************************************************************
 *
 * 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_blk_len &&
                acpi_gbl_FADT->xgpe0_blk.address) {
                /* GPE block 0 exists (has both length and address > 0) */

                register_count0 = (u16) (acpi_gbl_FADT->gpe0_blk_len / 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_blk, register_count0, 0,
                                 acpi_gbl_FADT->sci_int, &acpi_gbl_gpe_fadt_blocks[0]);

                if (ACPI_FAILURE (status)) {
                        ACPI_REPORT_ERROR ((
                                "Could not create GPE Block 0, %s\n",
                                acpi_format_exception (status)));
                }
        }

        if (acpi_gbl_FADT->gpe1_blk_len &&
                acpi_gbl_FADT->xgpe1_blk.address) {
                /* GPE block 1 exists (has both length and address > 0) */

                register_count1 = (u16) (acpi_gbl_FADT->gpe1_blk_len / 2);

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

                if ((register_count0) &&
                        (gpe_number_max >= acpi_gbl_FADT->gpe1_base)) {
                        ACPI_REPORT_ERROR ((
                                "GPE0 block (GPE 0 to %d) overlaps the GPE1 block (GPE %d to %d) - Ignoring GPE1\n",
                                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_blk, register_count1,
                                         acpi_gbl_FADT->gpe1_base,
                                         acpi_gbl_FADT->sci_int, &acpi_gbl_gpe_fadt_blocks[1]);

                        if (ACPI_FAILURE (status)) {
                                ACPI_REPORT_ERROR ((
                                        "Could not create GPE Block 1, %s\n",
                                        acpi_format_exception (status)));
                        }

                        /*
                         * 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_REPORT_ERROR (("Maximum GPE number from FADT is too large: 0x%X\n",
                        gpe_number_max));
                status = AE_BAD_VALUE;
                goto cleanup;
        }

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