rscalc.c

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/*******************************************************************************
 *
 * Module Name: rscalc - Calculate stream and list lengths
 *
 ******************************************************************************/

/*
 * Copyright (C) 2000 - 2006, 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/acresrc.h>
#include <acpi/amlcode.h>
#include <acpi/acnamesp.h>

#define _COMPONENT          ACPI_RESOURCES
ACPI_MODULE_NAME("rscalc")

/* Local prototypes */
static u8 acpi_rs_count_set_bits(u16 bit_field);

static acpi_rs_length
acpi_rs_struct_option_length(struct acpi_resource_source *resource_source);

static u32
acpi_rs_stream_option_length(u32 resource_length, u32 minimum_total_length);

/*******************************************************************************
 *
 * FUNCTION:    acpi_rs_count_set_bits
 *
 * PARAMETERS:  bit_field       - Field in which to count bits
 *
 * RETURN:      Number of bits set within the field
 *
 * DESCRIPTION: Count the number of bits set in a resource field. Used for
 *              (Short descriptor) interrupt and DMA lists.
 *
 ******************************************************************************/

static u8 acpi_rs_count_set_bits(u16 bit_field)
{
	u8 bits_set;

	ACPI_FUNCTION_ENTRY();

	for (bits_set = 0; bit_field; bits_set++) {
		/* Zero the least significant bit that is set */

		bit_field &= (bit_field - 1);
	}

	return (bits_set);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_rs_struct_option_length
 *
 * PARAMETERS:  resource_source     - Pointer to optional descriptor field
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Common code to handle optional resource_source_index and
 *              resource_source fields in some Large descriptors. Used during
 *              list-to-stream conversion
 *
 ******************************************************************************/

static acpi_rs_length
acpi_rs_struct_option_length(struct acpi_resource_source *resource_source)
{
	ACPI_FUNCTION_ENTRY();

	/*
	 * If the resource_source string is valid, return the size of the string
	 * (string_length includes the NULL terminator) plus the size of the
	 * resource_source_index (1).
	 */
	if (resource_source->string_ptr) {
		return ((acpi_rs_length) (resource_source->string_length + 1));
	}

	return (0);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_rs_stream_option_length
 *
 * PARAMETERS:  resource_length     - Length from the resource header
 *              minimum_total_length - Minimum length of this resource, before
 *                                    any optional fields. Includes header size
 *
 * RETURN:      Length of optional string (0 if no string present)
 *
 * DESCRIPTION: Common code to handle optional resource_source_index and
 *              resource_source fields in some Large descriptors. Used during
 *              stream-to-list conversion
 *
 ******************************************************************************/

static u32
acpi_rs_stream_option_length(u32 resource_length,
			     u32 minimum_aml_resource_length)
{
	u32 string_length = 0;

	ACPI_FUNCTION_ENTRY();

	/*
	 * The resource_source_index and resource_source are optional elements of some
	 * Large-type resource descriptors.
	 */

	/*
	 * If the length of the actual resource descriptor is greater than the ACPI
	 * spec-defined minimum length, it means that a resource_source_index exists
	 * and is followed by a (required) null terminated string. The string length
	 * (including the null terminator) is the resource length minus the minimum
	 * length, minus one byte for the resource_source_index itself.
	 */
	if (resource_length > minimum_aml_resource_length) {
		/* Compute the length of the optional string */

		string_length =
		    resource_length - minimum_aml_resource_length - 1;
	}

	/* Round up length to 32 bits for internal structure alignment */

	return (ACPI_ROUND_UP_to_32_bITS(string_length));
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_rs_get_aml_length
 *
 * PARAMETERS:  Resource            - Pointer to the resource linked list
 *              size_needed         - Where the required size is returned
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Takes a linked list of internal resource descriptors and
 *              calculates the size buffer needed to hold the corresponding
 *              external resource byte stream.
 *
 ******************************************************************************/

acpi_status
acpi_rs_get_aml_length(struct acpi_resource * resource, acpi_size * size_needed)
{
	acpi_size aml_size_needed = 0;
	acpi_rs_length total_size;

	ACPI_FUNCTION_TRACE("rs_get_aml_length");

	/* Traverse entire list of internal resource descriptors */

	while (resource) {
		/* Validate the descriptor type */

		if (resource->type > ACPI_RESOURCE_TYPE_MAX) {
			return_ACPI_STATUS(AE_AML_INVALID_RESOURCE_TYPE);
		}

		/* Get the base size of the (external stream) resource descriptor */

		total_size = acpi_gbl_aml_resource_sizes[resource->type];

		/*
		 * Augment the base size for descriptors with optional and/or
		 * variable-length fields
		 */
		switch (resource->type) {
		case ACPI_RESOURCE_TYPE_VENDOR:
			/*
			 * Vendor Defined Resource:
			 * For a Vendor Specific resource, if the Length is between 1 and 7
			 * it will be created as a Small Resource data type, otherwise it
			 * is a Large Resource data type.
			 */
			if (resource->data.vendor.byte_length > 7) {
				/* Base size of a Large resource descriptor */

				total_size =
				    sizeof(struct aml_resource_large_header);
			}

			/* Add the size of the vendor-specific data */

			total_size = (acpi_rs_length)
			    (total_size + resource->data.vendor.byte_length);
			break;

		case ACPI_RESOURCE_TYPE_END_TAG:
			/*
			 * End Tag:
			 * We are done -- return the accumulated total size.
			 */
			*size_needed = aml_size_needed + total_size;

			/* Normal exit */

			return_ACPI_STATUS(AE_OK);

		case ACPI_RESOURCE_TYPE_ADDRESS16:
			/*
			 * 16-Bit Address Resource:
			 * Add the size of the optional resource_source info
			 */
			total_size = (acpi_rs_length)
			    (total_size +
			     acpi_rs_struct_option_length(&resource->data.
							  address16.
							  resource_source));
			break;

		case ACPI_RESOURCE_TYPE_ADDRESS32:
			/*
			 * 32-Bit Address Resource:
			 * Add the size of the optional resource_source info
			 */
			total_size = (acpi_rs_length)
			    (total_size +
			     acpi_rs_struct_option_length(&resource->data.
							  address32.
							  resource_source));
			break;

		case ACPI_RESOURCE_TYPE_ADDRESS64:
			/*
			 * 64-Bit Address Resource:
			 * Add the size of the optional resource_source info
			 */
			total_size = (acpi_rs_length)
			    (total_size +
			     acpi_rs_struct_option_length(&resource->data.
							  address64.
							  resource_source));
			break;

		case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
			/*
			 * Extended IRQ Resource:
			 * Add the size of each additional optional interrupt beyond the
			 * required 1 (4 bytes for each u32 interrupt number)
			 */
			total_size = (acpi_rs_length)
			    (total_size +
			     ((resource->data.extended_irq.interrupt_count -
			       1) * 4) +
			     /* Add the size of the optional resource_source info */
			     acpi_rs_struct_option_length(&resource->data.
							  extended_irq.
							  resource_source));
			break;

		default:
			break;
		}

		/* Update the total */

		aml_size_needed += total_size;

		/* Point to the next object */