utresrc.c

来自「linux 内核源代码」· C语言 代码 · 共 616 行 · 第 1/2 页

		    ACPI_RESOURCE_NAME_END_TAG) {
			/*
			 * There must be at least one more byte in the buffer for
			 * the 2nd byte of the end_tag
			 */
			if ((aml + 1) >= end_aml) {
				return_ACPI_STATUS(AE_AML_NO_RESOURCE_END_TAG);
			}

			/* Return the pointer to the end_tag if requested */

			if (!user_function) {
				*context = aml;
			}

			/* Normal exit */

			return_ACPI_STATUS(AE_OK);
		}

		aml += length;
		offset += length;
	}

	/* Did not find an end_tag descriptor */

	return (AE_AML_NO_RESOURCE_END_TAG);
}

/*******************************************************************************
 *
 * 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 = ACPI_GET8(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 (ACPI_GET8(aml) & ACPI_RESOURCE_NAME_LARGE) {

		/* Large Resource Type -- bits 6:0 contain the name */

		return (ACPI_GET8(aml));
	} else {
		/* Small Resource Type -- bits 6:3 contain the name */

		return ((u8) (ACPI_GET8(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 (ACPI_GET8(aml) & ACPI_RESOURCE_NAME_LARGE) {

		/* Large Resource type -- bytes 1-2 contain the 16-bit length */

		ACPI_MOVE_16_TO_16(&resource_length, ACPI_ADD_PTR(u8, aml, 1));

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

		resource_length = (u16) (ACPI_GET8(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 (ACPI_GET8(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
 *              end_tag         - Where the pointer to the end_tag is returned
 *
 * RETURN:      Status, pointer to the end tag
 *
 * DESCRIPTION: Find the end_tag resource descriptor in an AML resource template
 *              Note: allows a buffer length of zero.
 *
 ******************************************************************************/

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

	ACPI_FUNCTION_TRACE(ut_get_resource_end_tag);

	/* Allow a buffer length of zero */

	if (!obj_desc->buffer.length) {
		*end_tag = obj_desc->buffer.pointer;
		return_ACPI_STATUS(AE_OK);
	}

	/* Validate the template and get a pointer to the end_tag */

	status = acpi_ut_walk_aml_resources(obj_desc->buffer.pointer,
					    obj_desc->buffer.length, NULL,
					    (void **)end_tag);

	return_ACPI_STATUS(status);
}