exprep.c

acpi tools for linux include acpiexec and acpixtract

/******************************************************************************
 *
 * Module Name: exprep - ACPI AML (p-code) execution - field prep utilities
 *              $Revision: 1.144 $
 *
 *****************************************************************************/

/******************************************************************************
 *
 * 1. Copyright Notice
 *
 * Some or all of this work - Copyright (c) 1999 - 2008, Intel Corp.
 * All rights reserved.
 *
 * 2. License
 *
 * 2.1. This is your license from Intel Corp. under its intellectual property
 * rights.  You may have additional license terms from the party that provided
 * you this software, covering your right to use that party's intellectual
 * property rights.
 *
 * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
 * copy of the source code appearing in this file ("Covered Code") an
 * irrevocable, perpetual, worldwide license under Intel's copyrights in the
 * base code distributed originally by Intel ("Original Intel Code") to copy,
 * make derivatives, distribute, use and display any portion of the Covered
 * Code in any form, with the right to sublicense such rights; and
 *
 * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
 * license (with the right to sublicense), under only those claims of Intel
 * patents that are infringed by the Original Intel Code, to make, use, sell,
 * offer to sell, and import the Covered Code and derivative works thereof
 * solely to the minimum extent necessary to exercise the above copyright
 * license, and in no event shall the patent license extend to any additions
 * to or modifications of the Original Intel Code.  No other license or right
 * is granted directly or by implication, estoppel or otherwise;
 *
 * The above copyright and patent license is granted only if the following
 * conditions are met:
 *
 * 3. Conditions
 *
 * 3.1. Redistribution of Source with Rights to Further Distribute Source.
 * Redistribution of source code of any substantial portion of the Covered
 * Code or modification with rights to further distribute source must include
 * the above Copyright Notice, the above License, this list of Conditions,
 * and the following Disclaimer and Export Compliance provision.  In addition,
 * Licensee must cause all Covered Code to which Licensee contributes to
 * contain a file documenting the changes Licensee made to create that Covered
 * Code and the date of any change.  Licensee must include in that file the
 * documentation of any changes made by any predecessor Licensee.  Licensee
 * must include a prominent statement that the modification is derived,
 * directly or indirectly, from Original Intel Code.
 *
 * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
 * Redistribution of source code of any substantial portion of the Covered
 * Code or modification without rights to further distribute source must
 * include the following Disclaimer and Export Compliance provision in the
 * documentation and/or other materials provided with distribution.  In
 * addition, Licensee may not authorize further sublicense of source of any
 * portion of the Covered Code, and must include terms to the effect that the
 * license from Licensee to its licensee is limited to the intellectual
 * property embodied in the software Licensee provides to its licensee, and
 * not to intellectual property embodied in modifications its licensee may
 * make.
 *
 * 3.3. Redistribution of Executable. Redistribution in executable form of any
 * substantial portion of the Covered Code or modification must reproduce the
 * above Copyright Notice, and the following Disclaimer and Export Compliance
 * provision in the documentation and/or other materials provided with the
 * distribution.
 *
 * 3.4. Intel retains all right, title, and interest in and to the Original
 * Intel Code.
 *
 * 3.5. Neither the name Intel nor any other trademark owned or controlled by
 * Intel shall be used in advertising or otherwise to promote the sale, use or
 * other dealings in products derived from or relating to the Covered Code
 * without prior written authorization from Intel.
 *
 * 4. Disclaimer and Export Compliance
 *
 * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
 * HERE.  ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
 * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT,  ASSISTANCE,
 * INSTALLATION, TRAINING OR OTHER SERVICES.  INTEL WILL NOT PROVIDE ANY
 * UPDATES, ENHANCEMENTS OR EXTENSIONS.  INTEL SPECIFICALLY DISCLAIMS ANY
 * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
 * PARTICULAR PURPOSE.
 *
 * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
 * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
 * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
 * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
 * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
 * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.  THESE LIMITATIONS
 * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
 * LIMITED REMEDY.
 *
 * 4.3. Licensee shall not export, either directly or indirectly, any of this
 * software or system incorporating such software without first obtaining any
 * required license or other approval from the U. S. Department of Commerce or
 * any other agency or department of the United States Government.  In the
 * event Licensee exports any such software from the United States or
 * re-exports any such software from a foreign destination, Licensee shall
 * ensure that the distribution and export/re-export of the software is in
 * compliance with all laws, regulations, orders, or other restrictions of the
 * U.S. Export Administration Regulations. Licensee agrees that neither it nor
 * any of its subsidiaries will export/re-export any technical data, process,
 * software, or service, directly or indirectly, to any country for which the
 * United States government or any agency thereof requires an export license,
 * other governmental approval, or letter of assurance, without first obtaining
 * such license, approval or letter.
 *
 *****************************************************************************/

#define __EXPREP_C__

#include "acpi.h"
#include "acinterp.h"
#include "amlcode.h"
#include "acnamesp.h"


#define _COMPONENT          ACPI_EXECUTER
        ACPI_MODULE_NAME    ("exprep")

/* Local prototypes */

static UINT32
AcpiExDecodeFieldAccess (
    ACPI_OPERAND_OBJECT     *ObjDesc,
    UINT8                   FieldFlags,
    UINT32                  *ReturnByteAlignment);


#ifdef ACPI_UNDER_DEVELOPMENT

static UINT32
AcpiExGenerateAccess (
    UINT32                  FieldBitOffset,
    UINT32                  FieldBitLength,
    UINT32                  RegionLength);

/*******************************************************************************
 *
 * FUNCTION:    AcpiExGenerateAccess
 *
 * PARAMETERS:  FieldBitOffset      - Start of field within parent region/buffer
 *              FieldBitLength      - Length of field in bits
 *              RegionLength        - Length of parent in bytes
 *
 * RETURN:      Field granularity (8, 16, 32 or 64) and
 *              ByteAlignment (1, 2, 3, or 4)
 *
 * DESCRIPTION: Generate an optimal access width for fields defined with the
 *              AnyAcc keyword.
 *
 * NOTE: Need to have the RegionLength in order to check for boundary
 *       conditions (end-of-region).  However, the RegionLength is a deferred
 *       operation.  Therefore, to complete this implementation, the generation
 *       of this access width must be deferred until the region length has
 *       been evaluated.
 *
 ******************************************************************************/

static UINT32
AcpiExGenerateAccess (
    UINT32                  FieldBitOffset,
    UINT32                  FieldBitLength,
    UINT32                  RegionLength)
{
    UINT32                  FieldByteLength;
    UINT32                  FieldByteOffset;
    UINT32                  FieldByteEndOffset;
    UINT32                  AccessByteWidth;
    UINT32                  FieldStartOffset;
    UINT32                  FieldEndOffset;
    UINT32                  MinimumAccessWidth = 0xFFFFFFFF;
    UINT32                  MinimumAccesses = 0xFFFFFFFF;
    UINT32                  Accesses;


    ACPI_FUNCTION_TRACE (ExGenerateAccess);


    /* Round Field start offset and length to "minimal" byte boundaries */

    FieldByteOffset    = ACPI_DIV_8 (ACPI_ROUND_DOWN (FieldBitOffset, 8));
    FieldByteEndOffset = ACPI_DIV_8 (ACPI_ROUND_UP   (FieldBitLength +
                                                      FieldBitOffset, 8));
    FieldByteLength    = FieldByteEndOffset - FieldByteOffset;

    ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
            "Bit length %d, Bit offset %d\n",
            FieldBitLength, FieldBitOffset));

    ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
            "Byte Length %d, Byte Offset %d, End Offset %d\n",
            FieldByteLength, FieldByteOffset, FieldByteEndOffset));

    /*
     * Iterative search for the maximum access width that is both aligned
     * and does not go beyond the end of the region
     *
     * Start at ByteAcc and work upwards to QwordAcc max. (1,2,4,8 bytes)
     */
    for (AccessByteWidth = 1; AccessByteWidth <= 8; AccessByteWidth <<= 1)
    {
        /*
         * 1) Round end offset up to next access boundary and make sure that
         *    this does not go beyond the end of the parent region.
         * 2) When the Access width is greater than the FieldByteLength, we
         *    are done. (This does not optimize for the perfectly aligned
         *    case yet).
         */
        if (ACPI_ROUND_UP (FieldByteEndOffset, AccessByteWidth) <= RegionLength)
        {
            FieldStartOffset =
                ACPI_ROUND_DOWN (FieldByteOffset, AccessByteWidth) /
                AccessByteWidth;

            FieldEndOffset =
                ACPI_ROUND_UP ((FieldByteLength + FieldByteOffset),
                    AccessByteWidth) / AccessByteWidth;

            Accesses = FieldEndOffset - FieldStartOffset;

            ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
                    "AccessWidth %d end is within region\n", AccessByteWidth));

            ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
                    "Field Start %d, Field End %d -- requires %d accesses\n",
                    FieldStartOffset, FieldEndOffset, Accesses));

            /* Single access is optimal */

            if (Accesses <= 1)
            {
                ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
                    "Entire field can be accessed with one operation of size %d\n",
                    AccessByteWidth));
                return_VALUE (AccessByteWidth);
            }

            /*
             * Fits in the region, but requires more than one read/write.
             * try the next wider access on next iteration
             */
            if (Accesses < MinimumAccesses)
            {
                MinimumAccesses    = Accesses;
                MinimumAccessWidth = AccessByteWidth;
            }
        }
        else
        {
            ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
                "AccessWidth %d end is NOT within region\n", AccessByteWidth));
            if (AccessByteWidth == 1)
            {
                ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
                        "Field goes beyond end-of-region!\n"));

                /* Field does not fit in the region at all */

                return_VALUE (0);
            }

            /*
             * This width goes beyond the end-of-region, back off to
             * previous access
             */
            ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
                    "Backing off to previous optimal access width of %d\n",
                    MinimumAccessWidth));
            return_VALUE (MinimumAccessWidth);
        }
    }

    /*
     * Could not read/write field with one operation,
     * just use max access width
     */
    ACPI_DEBUG_PRINT ((ACPI_DB_BFIELD,
            "Cannot access field in one operation, using width 8\n"));
    return_VALUE (8);
}
#endif /* ACPI_UNDER_DEVELOPMENT */


/*******************************************************************************
 *
 * FUNCTION:    AcpiExDecodeFieldAccess
 *
 * PARAMETERS:  ObjDesc             - Field object
 *              FieldFlags          - Encoded fieldflags (contains access bits)
 *              ReturnByteAlignment - Where the byte alignment is returned
 *
 * RETURN:      Field granularity (8, 16, 32 or 64) and
 *              ByteAlignment (1, 2, 3, or 4)
 *
 * DESCRIPTION: Decode the AccessType bits of a field definition.
 *
 ******************************************************************************/

static UINT32
AcpiExDecodeFieldAccess (
    ACPI_OPERAND_OBJECT     *ObjDesc,
    UINT8                   FieldFlags,
    UINT32                  *ReturnByteAlignment)
{
    UINT32                  Access;
    UINT32                  ByteAlignment;
    UINT32                  BitLength;


    ACPI_FUNCTION_TRACE (ExDecodeFieldAccess);


    Access = (FieldFlags & AML_FIELD_ACCESS_TYPE_MASK);

    switch (Access)
    {
    case AML_FIELD_ACCESS_ANY:

#ifdef ACPI_UNDER_DEVELOPMENT
        ByteAlignment =
            AcpiExGenerateAccess (ObjDesc->CommonField.StartFieldBitOffset,
                ObjDesc->CommonField.BitLength,
                0xFFFFFFFF /* Temp until we pass RegionLength as parameter */);
        BitLength = ByteAlignment * 8;
#endif

        ByteAlignment = 1;
        BitLength = 8;
        break;

    case AML_FIELD_ACCESS_BYTE:
    case AML_FIELD_ACCESS_BUFFER:   /* ACPI 2.0 (SMBus Buffer) */
        ByteAlignment = 1;
        BitLength     = 8;
        break;