linux/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
 *              Flags               - ACPI_NOT_ISR or ACPI_ISR
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Walk the GPE lists.
 *
 ******************************************************************************/

acpi_status
acpi_ev_walk_gpe_list (
	ACPI_GPE_CALLBACK       gpe_walk_callback,
	u32                             flags)
{
	struct acpi_gpe_block_info      *gpe_block;
	struct acpi_gpe_xrupt_info      *gpe_xrupt_info;
	acpi_status                     status = AE_OK;


	ACPI_FUNCTION_TRACE ("ev_walk_gpe_list");


	acpi_os_acquire_lock (acpi_gbl_gpe_lock, flags);

	/* 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;


	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 */

	acpi_os_acquire_lock (acpi_gbl_gpe_lock, ACPI_NOT_ISR);
	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, ACPI_NOT_ISR);

	/* 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;


	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 */

	acpi_os_acquire_lock (acpi_gbl_gpe_lock, ACPI_NOT_ISR);
	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, ACPI_NOT_ISR);

	/* 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;


	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 */

	acpi_os_acquire_lock (acpi_gbl_gpe_lock, ACPI_NOT_ISR);
	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, ACPI_NOT_ISR);

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_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 */

		acpi_os_acquire_lock (acpi_gbl_gpe_lock, ACPI_NOT_ISR);
		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, ACPI_NOT_ISR);
	}

	/* 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);
}