path: root/drivers/acpi/utilities/utresrc.c

/*******************************************************************************
 *
 * Module Name: utresrc - Resource managment utilities
 *
 ******************************************************************************/

/*
 * 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/amlresrc.h>

#define _COMPONENT          ACPI_UTILITIES
ACPI_MODULE_NAME("utmisc")

/*
 * Base sizes of the raw AML resource descriptors, indexed by resource type.
 * Zero indicates a reserved (and therefore invalid) resource type.
 */
const u8 acpi_gbl_resource_aml_sizes[] = {
	/* Small descriptors */

	0,
	0,
	0,
	0,
	ACPI_AML_SIZE_SMALL(struct aml_resource_irq),
	ACPI_AML_SIZE_SMALL(struct aml_resource_dma),
	ACPI_AML_SIZE_SMALL(struct aml_resource_start_dependent),
	ACPI_AML_SIZE_SMALL(struct aml_resource_end_dependent),
	ACPI_AML_SIZE_SMALL(struct aml_resource_io),
	ACPI_AML_SIZE_SMALL(struct aml_resource_fixed_io),
	0,
	0,
	0,
	0,
	ACPI_AML_SIZE_SMALL(struct aml_resource_vendor_small),
	ACPI_AML_SIZE_SMALL(struct aml_resource_end_tag),

	/* Large descriptors */

	0,
	ACPI_AML_SIZE_LARGE(struct aml_resource_memory24),
	ACPI_AML_SIZE_LARGE(struct aml_resource_generic_register),
	0,
	ACPI_AML_SIZE_LARGE(struct aml_resource_vendor_large),
	ACPI_AML_SIZE_LARGE(struct aml_resource_memory32),
	ACPI_AML_SIZE_LARGE(struct aml_resource_fixed_memory32),
	ACPI_AML_SIZE_LARGE(struct aml_resource_address32),
	ACPI_AML_SIZE_LARGE(struct aml_resource_address16),
	ACPI_AML_SIZE_LARGE(struct aml_resource_extended_irq),
	ACPI_AML_SIZE_LARGE(struct aml_resource_address64),
	ACPI_AML_SIZE_LARGE(struct aml_resource_extended_address64)
};

/*
 * Resource types, used to validate the resource length field.
 * The length of fixed-length types must match exactly, variable
 * lengths must meet the minimum required length, etc.
 * Zero indicates a reserved (and therefore invalid) resource type.
 */
static const u8 acpi_gbl_resource_types[] = {
	/* Small descriptors */

	0,
	0,
	0,
	0,
	ACPI_SMALL_VARIABLE_LENGTH,
	ACPI_FIXED_LENGTH,
	ACPI_SMALL_VARIABLE_LENGTH,
	ACPI_FIXED_LENGTH,
	ACPI_FIXED_LENGTH,
	ACPI_FIXED_LENGTH,
	0,
	0,
	0,
	0,
	ACPI_VARIABLE_LENGTH,
	ACPI_FIXED_LENGTH,

	/* Large descriptors */

	0,
	ACPI_FIXED_LENGTH,
	ACPI_FIXED_LENGTH,
	0,
	ACPI_VARIABLE_LENGTH,
	ACPI_FIXED_LENGTH,
	ACPI_FIXED_LENGTH,
	ACPI_VARIABLE_LENGTH,
	ACPI_VARIABLE_LENGTH,
	ACPI_VARIABLE_LENGTH,
	ACPI_VARIABLE_LENGTH,
	ACPI_FIXED_LENGTH
};

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_validate_resource
 *
 * PARAMETERS:  Aml             - Pointer to the raw AML resource descriptor
 *              return_index    - Where the resource index is returned. NULL
 *                                if the index is not required.
 *
 * RETURN:      Status, and optionally the Index into the global resource tables
 *
 * DESCRIPTION: Validate an AML resource descriptor by checking the Resource
 *              Type and Resource Length. Returns an index into the global
 *              resource information/dispatch tables for later use.
 *
 ******************************************************************************/

acpi_status acpi_ut_validate_resource(void *aml, u8 * return_index)
{
	u8 resource_type;
	u8 resource_index;
	acpi_rs_length resource_length;
	acpi_rs_length minimum_resource_length;

	ACPI_FUNCTION_ENTRY();

	/*
	 * 1) Validate the resource_type field (Byte 0)
	 */
	resource_type = *((u8 *) aml);

	/*
	 * Byte 0 contains the descriptor name (Resource Type)
	 * Examine the large/small bit in the resource header
	 */
	if (resource_type & ACPI_RESOURCE_NAME_LARGE) {
		/* Verify the large resource type (name) against the max */

		if (resource_type > ACPI_RESOURCE_NAME_LARGE_MAX) {
			return (AE_AML_INVALID_RESOURCE_TYPE);
		}

		/*
		 * Large Resource Type -- bits 6:0 contain the name
		 * Translate range 0x80-0x8B to index range 0x10-0x1B
		 */
		resource_index = (u8) (resource_type - 0x70);
	} else {
		/*
		 * Small Resource Type -- bits 6:3 contain the name
		 * Shift range to index range 0x00-0x0F
		 */
		resource_index = (u8)
		    ((resource_type & ACPI_RESOURCE_NAME_SMALL_MASK) >> 3);
	}

	/* Check validity of the resource type, zero indicates name is invalid */

	if (!acpi_gbl_resource_types[resource_index]) {
		return (AE_AML_INVALID_RESOURCE_TYPE);
	}

	/*
	 * 2) Validate the resource_length field. This ensures that the length
	 *    is at least reasonable, and guarantees that it is non-zero.
	 */
	resource_length = acpi_ut_get_resource_length(aml);
	minimum_resource_length = acpi_gbl_resource_aml_sizes[resource_index];

	/* Validate based upon the type of resource - fixed length or variable */

	switch (acpi_gbl_resource_types[resource_index]) {
	case ACPI_FIXED_LENGTH:

		/* Fixed length resource, length must match exactly */

		if (resource_length != minimum_resource_length) {
			return (AE_AML_BAD_RESOURCE_LENGTH);
		}
		break;

	case ACPI_VARIABLE_LENGTH:

		/* Variable length resource, length must be at least the minimum */

		if (resource_length < minimum_resource_length) {
			return (AE_AML_BAD_RESOURCE_LENGTH);
		}
		break;

	case ACPI_SMALL_VARIABLE_LENGTH:

		/* Small variable length resource, length can be (Min) or (Min-1) */

		if ((resource_length > minimum_resource_length) ||
		    (resource_length < (minimum_resource_length - 1))) {
			return (AE_AML_BAD_RESOURCE_LENGTH);
		}
		break;

	default:

		/* Shouldn't happen (because of validation earlier), but be sure */

		return (AE_AML_INVALID_RESOURCE_TYPE);
	}

	/* Optionally return the resource table index */

	if (return_index) {
		*return_index = resource_index;
	}

	return (AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_get_resource_type
 *
 * PARAMETERS:  Aml             - Pointer to the raw AML resource descriptor
 *
 * RETURN:      The Resource Type with no extraneous bits (except the
 *              Large/Small descriptor bit -- this is left alone)
 *
 * DESCRIPTION: Extract the Resource Type/Name from the first byte of
 *              a resource descriptor.
 *
 ******************************************************************************/

u8 acpi_ut_get_resource_type(void *aml)
{
	ACPI_FUNCTION_ENTRY();

	/*
	 * Byte 0 contains the descriptor name (Resource Type)
	 * Examine the large/small bit in the resource header
	 */
	if (*((u8 *) aml) & ACPI_RESOURCE_NAME_LARGE) {
		/* Large Resource Type -- bits 6:0 contain the name */

		return (*((u8 *) aml));
	} else {
		/* Small Resource Type -- bits 6:3 contain the name */

		return ((u8) (*((u8 *) aml) & ACPI_RESOURCE_NAME_SMALL_MASK));
	}
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_get_resource_length
 *
 * PARAMETERS:  Aml             - Pointer to the raw AML resource descriptor
 *
 * RETURN:      Byte Length
 *
 * DESCRIPTION: Get the "Resource Length" of a raw AML descriptor. By
 *              definition, this does not include the size of the descriptor
 *              header or the length field itself.
 *
 ******************************************************************************/

u16 acpi_ut_get_resource_length(void *aml)
{
	acpi_rs_length resource_length;

	ACPI_FUNCTION_ENTRY();

	/*
	 * Byte 0 contains the descriptor name (Resource Type)
	 * Examine the large/small bit in the resource header
	 */
	if (*((u8 *) aml) & ACPI_RESOURCE_NAME_LARGE) {
		/* Large Resource type -- bytes 1-2 contain the 16-bit length */

		ACPI_MOVE_16_TO_16(&resource_length, &((u8 *) aml)[1]);

	} else {
		/* Small Resource type -- bits 2:0 of byte 0 contain the length */

		resource_length = (u16) (*((u8 *) aml) &
					 ACPI_RESOURCE_NAME_SMALL_LENGTH_MASK);
	}

	return (resource_length);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_get_resource_header_length
 *
 * PARAMETERS:  Aml             - Pointer to the raw AML resource descriptor
 *
 * RETURN:      Length of the AML header (depends on large/small descriptor)
 *
 * DESCRIPTION: Get the length of the header for this resource.
 *
 ******************************************************************************/

u8 acpi_ut_get_resource_header_length(void *aml)
{
	ACPI_FUNCTION_ENTRY();

	/* Examine the large/small bit in the resource header */

	if (*((u8 *) aml) & ACPI_RESOURCE_NAME_LARGE) {
		return (sizeof(struct aml_resource_large_header));
	} else {
		return (sizeof(struct aml_resource_small_header));
	}
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_get_descriptor_length
 *
 * PARAMETERS:  Aml             - Pointer to the raw AML resource descriptor
 *
 * RETURN:      Byte length
 *
 * DESCRIPTION: Get the total byte length of a raw AML descriptor, including the
 *              length of the descriptor header and the length field itself.
 *              Used to walk descriptor lists.
 *
 ******************************************************************************/

u32 acpi_ut_get_descriptor_length(void *aml)
{
	ACPI_FUNCTION_ENTRY();

	/*
	 * Get the Resource Length (does not include header length) and add
	 * the header length (depends on if this is a small or large resource)
	 */
	return (acpi_ut_get_resource_length(aml) +
		acpi_ut_get_resource_header_length(aml));
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_get_resource_end_tag
 *
 * PARAMETERS:  obj_desc        - The resource template buffer object
 *
 * RETURN:      Pointer to the end tag
 *
 * DESCRIPTION: Find the end_tag resource descriptor in an AML resource template
 *
 ******************************************************************************/

acpi_status
acpi_ut_get_resource_end_tag(union acpi_operand_object * obj_desc,
			     u8 ** end_tag)
{
	acpi_status status;
	u8 *aml;
	u8 *end_aml;

	ACPI_FUNCTION_TRACE("ut_get_resource_end_tag");

	/* Get start and end pointers */

	aml = obj_desc->buffer.pointer;
	end_aml = aml + obj_desc->buffer.length;

	/* Walk the resource template, one descriptor per iteration */

	while (aml < end_aml) {
		/* Validate the Resource Type and Resource Length */

		status = acpi_ut_validate_resource(aml, NULL);
		if (ACPI_FAILURE(status)) {
			return_ACPI_STATUS(status);
		}

		/* end_tag resource indicates the end of the resource template */

		if (acpi_ut_get_resource_type(aml) ==
		    ACPI_RESOURCE_NAME_END_TAG) {
			/* Return the pointer to the end_tag */

			*end_tag = aml;
			return_ACPI_STATUS(AE_OK);
		}

		/*
		 * Point to the next resource descriptor in the AML buffer. The
		 * descriptor length is guaranteed to be non-zero by resource
		 * validation above.
		 */
		aml += acpi_ut_get_descriptor_length(aml);
	}

	/* Did not find an end_tag resource descriptor */

	return_ACPI_STATUS(AE_AML_NO_RESOURCE_END_TAG);
}