xref: /freebsd-src/sys/contrib/dev/acpica/components/utilities/utcksum.c (revision 804fe2660352e090f4481f2c1d646b508859e79a)
19a4bc520SJung-uk Kim /******************************************************************************
29a4bc520SJung-uk Kim  *
39a4bc520SJung-uk Kim  * Module Name: utcksum - Support generating table checksums
49a4bc520SJung-uk Kim  *
59a4bc520SJung-uk Kim  *****************************************************************************/
69a4bc520SJung-uk Kim 
79a4bc520SJung-uk Kim /******************************************************************************
89a4bc520SJung-uk Kim  *
99a4bc520SJung-uk Kim  * 1. Copyright Notice
109a4bc520SJung-uk Kim  *
11*804fe266SJung-uk Kim  * Some or all of this work - Copyright (c) 1999 - 2024, Intel Corp.
129a4bc520SJung-uk Kim  * All rights reserved.
139a4bc520SJung-uk Kim  *
149a4bc520SJung-uk Kim  * 2. License
159a4bc520SJung-uk Kim  *
169a4bc520SJung-uk Kim  * 2.1. This is your license from Intel Corp. under its intellectual property
179a4bc520SJung-uk Kim  * rights. You may have additional license terms from the party that provided
189a4bc520SJung-uk Kim  * you this software, covering your right to use that party's intellectual
199a4bc520SJung-uk Kim  * property rights.
209a4bc520SJung-uk Kim  *
219a4bc520SJung-uk Kim  * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
229a4bc520SJung-uk Kim  * copy of the source code appearing in this file ("Covered Code") an
239a4bc520SJung-uk Kim  * irrevocable, perpetual, worldwide license under Intel's copyrights in the
249a4bc520SJung-uk Kim  * base code distributed originally by Intel ("Original Intel Code") to copy,
259a4bc520SJung-uk Kim  * make derivatives, distribute, use and display any portion of the Covered
269a4bc520SJung-uk Kim  * Code in any form, with the right to sublicense such rights; and
279a4bc520SJung-uk Kim  *
289a4bc520SJung-uk Kim  * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
299a4bc520SJung-uk Kim  * license (with the right to sublicense), under only those claims of Intel
309a4bc520SJung-uk Kim  * patents that are infringed by the Original Intel Code, to make, use, sell,
319a4bc520SJung-uk Kim  * offer to sell, and import the Covered Code and derivative works thereof
329a4bc520SJung-uk Kim  * solely to the minimum extent necessary to exercise the above copyright
339a4bc520SJung-uk Kim  * license, and in no event shall the patent license extend to any additions
349a4bc520SJung-uk Kim  * to or modifications of the Original Intel Code. No other license or right
359a4bc520SJung-uk Kim  * is granted directly or by implication, estoppel or otherwise;
369a4bc520SJung-uk Kim  *
379a4bc520SJung-uk Kim  * The above copyright and patent license is granted only if the following
389a4bc520SJung-uk Kim  * conditions are met:
399a4bc520SJung-uk Kim  *
409a4bc520SJung-uk Kim  * 3. Conditions
419a4bc520SJung-uk Kim  *
429a4bc520SJung-uk Kim  * 3.1. Redistribution of Source with Rights to Further Distribute Source.
439a4bc520SJung-uk Kim  * Redistribution of source code of any substantial portion of the Covered
449a4bc520SJung-uk Kim  * Code or modification with rights to further distribute source must include
459a4bc520SJung-uk Kim  * the above Copyright Notice, the above License, this list of Conditions,
469a4bc520SJung-uk Kim  * and the following Disclaimer and Export Compliance provision. In addition,
479a4bc520SJung-uk Kim  * Licensee must cause all Covered Code to which Licensee contributes to
489a4bc520SJung-uk Kim  * contain a file documenting the changes Licensee made to create that Covered
499a4bc520SJung-uk Kim  * Code and the date of any change. Licensee must include in that file the
509a4bc520SJung-uk Kim  * documentation of any changes made by any predecessor Licensee. Licensee
519a4bc520SJung-uk Kim  * must include a prominent statement that the modification is derived,
529a4bc520SJung-uk Kim  * directly or indirectly, from Original Intel Code.
539a4bc520SJung-uk Kim  *
549a4bc520SJung-uk Kim  * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
559a4bc520SJung-uk Kim  * Redistribution of source code of any substantial portion of the Covered
569a4bc520SJung-uk Kim  * Code or modification without rights to further distribute source must
579a4bc520SJung-uk Kim  * include the following Disclaimer and Export Compliance provision in the
589a4bc520SJung-uk Kim  * documentation and/or other materials provided with distribution. In
599a4bc520SJung-uk Kim  * addition, Licensee may not authorize further sublicense of source of any
609a4bc520SJung-uk Kim  * portion of the Covered Code, and must include terms to the effect that the
619a4bc520SJung-uk Kim  * license from Licensee to its licensee is limited to the intellectual
629a4bc520SJung-uk Kim  * property embodied in the software Licensee provides to its licensee, and
639a4bc520SJung-uk Kim  * not to intellectual property embodied in modifications its licensee may
649a4bc520SJung-uk Kim  * make.
659a4bc520SJung-uk Kim  *
669a4bc520SJung-uk Kim  * 3.3. Redistribution of Executable. Redistribution in executable form of any
679a4bc520SJung-uk Kim  * substantial portion of the Covered Code or modification must reproduce the
689a4bc520SJung-uk Kim  * above Copyright Notice, and the following Disclaimer and Export Compliance
699a4bc520SJung-uk Kim  * provision in the documentation and/or other materials provided with the
709a4bc520SJung-uk Kim  * distribution.
719a4bc520SJung-uk Kim  *
729a4bc520SJung-uk Kim  * 3.4. Intel retains all right, title, and interest in and to the Original
739a4bc520SJung-uk Kim  * Intel Code.
749a4bc520SJung-uk Kim  *
759a4bc520SJung-uk Kim  * 3.5. Neither the name Intel nor any other trademark owned or controlled by
769a4bc520SJung-uk Kim  * Intel shall be used in advertising or otherwise to promote the sale, use or
779a4bc520SJung-uk Kim  * other dealings in products derived from or relating to the Covered Code
789a4bc520SJung-uk Kim  * without prior written authorization from Intel.
799a4bc520SJung-uk Kim  *
809a4bc520SJung-uk Kim  * 4. Disclaimer and Export Compliance
819a4bc520SJung-uk Kim  *
829a4bc520SJung-uk Kim  * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
839a4bc520SJung-uk Kim  * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
849a4bc520SJung-uk Kim  * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE,
859a4bc520SJung-uk Kim  * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY
869a4bc520SJung-uk Kim  * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY
879a4bc520SJung-uk Kim  * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
889a4bc520SJung-uk Kim  * PARTICULAR PURPOSE.
899a4bc520SJung-uk Kim  *
909a4bc520SJung-uk Kim  * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
919a4bc520SJung-uk Kim  * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
929a4bc520SJung-uk Kim  * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
939a4bc520SJung-uk Kim  * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
949a4bc520SJung-uk Kim  * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
959a4bc520SJung-uk Kim  * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS
969a4bc520SJung-uk Kim  * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
979a4bc520SJung-uk Kim  * LIMITED REMEDY.
989a4bc520SJung-uk Kim  *
999a4bc520SJung-uk Kim  * 4.3. Licensee shall not export, either directly or indirectly, any of this
1009a4bc520SJung-uk Kim  * software or system incorporating such software without first obtaining any
1019a4bc520SJung-uk Kim  * required license or other approval from the U. S. Department of Commerce or
1029a4bc520SJung-uk Kim  * any other agency or department of the United States Government. In the
1039a4bc520SJung-uk Kim  * event Licensee exports any such software from the United States or
1049a4bc520SJung-uk Kim  * re-exports any such software from a foreign destination, Licensee shall
1059a4bc520SJung-uk Kim  * ensure that the distribution and export/re-export of the software is in
1069a4bc520SJung-uk Kim  * compliance with all laws, regulations, orders, or other restrictions of the
1079a4bc520SJung-uk Kim  * U.S. Export Administration Regulations. Licensee agrees that neither it nor
1089a4bc520SJung-uk Kim  * any of its subsidiaries will export/re-export any technical data, process,
1099a4bc520SJung-uk Kim  * software, or service, directly or indirectly, to any country for which the
1109a4bc520SJung-uk Kim  * United States government or any agency thereof requires an export license,
1119a4bc520SJung-uk Kim  * other governmental approval, or letter of assurance, without first obtaining
1129a4bc520SJung-uk Kim  * such license, approval or letter.
1139a4bc520SJung-uk Kim  *
1149a4bc520SJung-uk Kim  *****************************************************************************
1159a4bc520SJung-uk Kim  *
1169a4bc520SJung-uk Kim  * Alternatively, you may choose to be licensed under the terms of the
1179a4bc520SJung-uk Kim  * following license:
1189a4bc520SJung-uk Kim  *
1199a4bc520SJung-uk Kim  * Redistribution and use in source and binary forms, with or without
1209a4bc520SJung-uk Kim  * modification, are permitted provided that the following conditions
1219a4bc520SJung-uk Kim  * are met:
1229a4bc520SJung-uk Kim  * 1. Redistributions of source code must retain the above copyright
1239a4bc520SJung-uk Kim  *    notice, this list of conditions, and the following disclaimer,
1249a4bc520SJung-uk Kim  *    without modification.
1259a4bc520SJung-uk Kim  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
1269a4bc520SJung-uk Kim  *    substantially similar to the "NO WARRANTY" disclaimer below
1279a4bc520SJung-uk Kim  *    ("Disclaimer") and any redistribution must be conditioned upon
1289a4bc520SJung-uk Kim  *    including a substantially similar Disclaimer requirement for further
1299a4bc520SJung-uk Kim  *    binary redistribution.
1309a4bc520SJung-uk Kim  * 3. Neither the names of the above-listed copyright holders nor the names
1319a4bc520SJung-uk Kim  *    of any contributors may be used to endorse or promote products derived
1329a4bc520SJung-uk Kim  *    from this software without specific prior written permission.
1339a4bc520SJung-uk Kim  *
1349a4bc520SJung-uk Kim  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
1359a4bc520SJung-uk Kim  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
1369a4bc520SJung-uk Kim  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
1379a4bc520SJung-uk Kim  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
1389a4bc520SJung-uk Kim  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
1399a4bc520SJung-uk Kim  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
1409a4bc520SJung-uk Kim  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
1419a4bc520SJung-uk Kim  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
1429a4bc520SJung-uk Kim  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
1439a4bc520SJung-uk Kim  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
1449a4bc520SJung-uk Kim  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1459a4bc520SJung-uk Kim  *
1469a4bc520SJung-uk Kim  * Alternatively, you may choose to be licensed under the terms of the
1479a4bc520SJung-uk Kim  * GNU General Public License ("GPL") version 2 as published by the Free
1489a4bc520SJung-uk Kim  * Software Foundation.
1499a4bc520SJung-uk Kim  *
1509a4bc520SJung-uk Kim  *****************************************************************************/
1519a4bc520SJung-uk Kim 
1529a4bc520SJung-uk Kim #include <contrib/dev/acpica/include/acpi.h>
1539a4bc520SJung-uk Kim #include <contrib/dev/acpica/include/accommon.h>
1549a4bc520SJung-uk Kim #include <contrib/dev/acpica/include/acdisasm.h>
1559a4bc520SJung-uk Kim #include <contrib/dev/acpica/include/acutils.h>
1569a4bc520SJung-uk Kim 
1579a4bc520SJung-uk Kim 
1589a4bc520SJung-uk Kim /* This module used for application-level code only */
1599a4bc520SJung-uk Kim 
1609a4bc520SJung-uk Kim #define _COMPONENT          ACPI_CA_DISASSEMBLER
1619a4bc520SJung-uk Kim         ACPI_MODULE_NAME    ("utcksum")
1629a4bc520SJung-uk Kim 
1639a4bc520SJung-uk Kim 
1649a4bc520SJung-uk Kim /*******************************************************************************
1659a4bc520SJung-uk Kim  *
1669a4bc520SJung-uk Kim  * FUNCTION:    AcpiUtVerifyChecksum
1679a4bc520SJung-uk Kim  *
1689a4bc520SJung-uk Kim  * PARAMETERS:  Table               - ACPI table to verify
1699a4bc520SJung-uk Kim  *              Length              - Length of entire table
1709a4bc520SJung-uk Kim  *
1719a4bc520SJung-uk Kim  * RETURN:      Status
1729a4bc520SJung-uk Kim  *
1739a4bc520SJung-uk Kim  * DESCRIPTION: Verifies that the table checksums to zero. Optionally returns
1749a4bc520SJung-uk Kim  *              exception on bad checksum.
1759a4bc520SJung-uk Kim  *              Note: We don't have to check for a CDAT here, since CDAT is
1769a4bc520SJung-uk Kim  *              not in the RSDT/XSDT, and the CDAT table is never installed
1779a4bc520SJung-uk Kim  *              via ACPICA.
1789a4bc520SJung-uk Kim  *
1799a4bc520SJung-uk Kim  ******************************************************************************/
1809a4bc520SJung-uk Kim 
1819a4bc520SJung-uk Kim ACPI_STATUS
1829a4bc520SJung-uk Kim AcpiUtVerifyChecksum (
1839a4bc520SJung-uk Kim     ACPI_TABLE_HEADER       *Table,
1849a4bc520SJung-uk Kim     UINT32                  Length)
1859a4bc520SJung-uk Kim {
1869a4bc520SJung-uk Kim     UINT8                   Checksum;
1879a4bc520SJung-uk Kim 
1889a4bc520SJung-uk Kim 
1899a4bc520SJung-uk Kim     /*
1909a4bc520SJung-uk Kim      * FACS/S3PT:
1919a4bc520SJung-uk Kim      * They are the odd tables, have no standard ACPI header and no checksum
1929a4bc520SJung-uk Kim      */
1939a4bc520SJung-uk Kim     if (ACPI_COMPARE_NAMESEG (Table->Signature, ACPI_SIG_S3PT) ||
1949a4bc520SJung-uk Kim         ACPI_COMPARE_NAMESEG (Table->Signature, ACPI_SIG_FACS))
1959a4bc520SJung-uk Kim     {
1969a4bc520SJung-uk Kim         return (AE_OK);
1979a4bc520SJung-uk Kim     }
1989a4bc520SJung-uk Kim 
1999a4bc520SJung-uk Kim     /* Compute the checksum on the table */
2009a4bc520SJung-uk Kim 
2019a4bc520SJung-uk Kim     Length = Table->Length;
2029a4bc520SJung-uk Kim     Checksum = AcpiUtGenerateChecksum (ACPI_CAST_PTR (UINT8, Table), Length, Table->Checksum);
2039a4bc520SJung-uk Kim 
2049a4bc520SJung-uk Kim     /* Computed checksum matches table? */
2059a4bc520SJung-uk Kim 
2069a4bc520SJung-uk Kim     if (Checksum != Table->Checksum)
2079a4bc520SJung-uk Kim     {
2089a4bc520SJung-uk Kim         ACPI_BIOS_WARNING ((AE_INFO,
2099a4bc520SJung-uk Kim             "Incorrect checksum in table [%4.4s] - 0x%2.2X, "
2109a4bc520SJung-uk Kim             "should be 0x%2.2X",
2119a4bc520SJung-uk Kim             Table->Signature, Table->Checksum,
2129a4bc520SJung-uk Kim             Table->Checksum - Checksum));
2139a4bc520SJung-uk Kim 
2149a4bc520SJung-uk Kim #if (ACPI_CHECKSUM_ABORT)
2159a4bc520SJung-uk Kim         return (AE_BAD_CHECKSUM);
2169a4bc520SJung-uk Kim #endif
2179a4bc520SJung-uk Kim     }
2189a4bc520SJung-uk Kim 
2199a4bc520SJung-uk Kim     return (AE_OK);
2209a4bc520SJung-uk Kim }
2219a4bc520SJung-uk Kim 
2229a4bc520SJung-uk Kim 
2239a4bc520SJung-uk Kim /*******************************************************************************
2249a4bc520SJung-uk Kim  *
2259a4bc520SJung-uk Kim  * FUNCTION:    AcpiUtVerifyCdatChecksum
2269a4bc520SJung-uk Kim  *
2279a4bc520SJung-uk Kim  * PARAMETERS:  Table               - CDAT ACPI table to verify
2289a4bc520SJung-uk Kim  *              Length              - Length of entire table
2299a4bc520SJung-uk Kim  *
2309a4bc520SJung-uk Kim  * RETURN:      Status
2319a4bc520SJung-uk Kim  *
2329a4bc520SJung-uk Kim  * DESCRIPTION: Verifies that the CDAT table checksums to zero. Optionally
2339a4bc520SJung-uk Kim  *              returns an exception on bad checksum.
2349a4bc520SJung-uk Kim  *
2359a4bc520SJung-uk Kim  ******************************************************************************/
2369a4bc520SJung-uk Kim 
2379a4bc520SJung-uk Kim ACPI_STATUS
2389a4bc520SJung-uk Kim AcpiUtVerifyCdatChecksum (
2399a4bc520SJung-uk Kim     ACPI_TABLE_CDAT         *CdatTable,
2409a4bc520SJung-uk Kim     UINT32                  Length)
2419a4bc520SJung-uk Kim {
2429a4bc520SJung-uk Kim     UINT8                   Checksum;
2439a4bc520SJung-uk Kim 
2449a4bc520SJung-uk Kim 
2459a4bc520SJung-uk Kim     /* Compute the checksum on the table */
2469a4bc520SJung-uk Kim 
2479a4bc520SJung-uk Kim     Checksum = AcpiUtGenerateChecksum (ACPI_CAST_PTR (UINT8, CdatTable),
2489a4bc520SJung-uk Kim                     CdatTable->Length, CdatTable->Checksum);
2499a4bc520SJung-uk Kim 
2509a4bc520SJung-uk Kim     /* Computed checksum matches table? */
2519a4bc520SJung-uk Kim 
2529a4bc520SJung-uk Kim     if (Checksum != CdatTable->Checksum)
2539a4bc520SJung-uk Kim     {
2549a4bc520SJung-uk Kim         ACPI_BIOS_WARNING ((AE_INFO,
2559a4bc520SJung-uk Kim             "Incorrect checksum in table [%4.4s] - 0x%2.2X, "
2569a4bc520SJung-uk Kim             "should be 0x%2.2X",
2579a4bc520SJung-uk Kim             AcpiGbl_CDAT, CdatTable->Checksum, Checksum));
2589a4bc520SJung-uk Kim 
2599a4bc520SJung-uk Kim #if (ACPI_CHECKSUM_ABORT)
2609a4bc520SJung-uk Kim         return (AE_BAD_CHECKSUM);
2619a4bc520SJung-uk Kim #endif
2629a4bc520SJung-uk Kim     }
2639a4bc520SJung-uk Kim 
2649a4bc520SJung-uk Kim     CdatTable->Checksum = Checksum;
2659a4bc520SJung-uk Kim     return (AE_OK);
2669a4bc520SJung-uk Kim }
2679a4bc520SJung-uk Kim 
2689a4bc520SJung-uk Kim 
2699a4bc520SJung-uk Kim /*******************************************************************************
2709a4bc520SJung-uk Kim  *
2719a4bc520SJung-uk Kim  * FUNCTION:    AcpiUtGenerateChecksum
2729a4bc520SJung-uk Kim  *
2739a4bc520SJung-uk Kim  * PARAMETERS:  Table               - Pointer to table to be checksummed
2749a4bc520SJung-uk Kim  *              Length              - Length of the table
2759a4bc520SJung-uk Kim  *              OriginalChecksum    - Value of the checksum field
2769a4bc520SJung-uk Kim  *
2779a4bc520SJung-uk Kim  * RETURN:      8 bit checksum of buffer
2789a4bc520SJung-uk Kim  *
2799a4bc520SJung-uk Kim  * DESCRIPTION: Computes an 8 bit checksum of the table.
2809a4bc520SJung-uk Kim  *
2819a4bc520SJung-uk Kim  ******************************************************************************/
2829a4bc520SJung-uk Kim 
2839a4bc520SJung-uk Kim UINT8
2849a4bc520SJung-uk Kim AcpiUtGenerateChecksum (
2859a4bc520SJung-uk Kim     void                    *Table,
2869a4bc520SJung-uk Kim     UINT32                  Length,
2879a4bc520SJung-uk Kim     UINT8                   OriginalChecksum)
2889a4bc520SJung-uk Kim {
2899a4bc520SJung-uk Kim     UINT8                   Checksum;
2909a4bc520SJung-uk Kim 
2919a4bc520SJung-uk Kim 
2929a4bc520SJung-uk Kim     /* Sum the entire table as-is */
2939a4bc520SJung-uk Kim 
2949a4bc520SJung-uk Kim     Checksum = AcpiUtChecksum ((UINT8 *) Table, Length);
2959a4bc520SJung-uk Kim 
2969a4bc520SJung-uk Kim     /* Subtract off the existing checksum value in the table */
2979a4bc520SJung-uk Kim 
2989a4bc520SJung-uk Kim     Checksum = (UINT8) (Checksum - OriginalChecksum);
2999a4bc520SJung-uk Kim 
3009a4bc520SJung-uk Kim     /* Compute and return the final checksum */
3019a4bc520SJung-uk Kim 
3029a4bc520SJung-uk Kim     Checksum = (UINT8) (0 - Checksum);
3039a4bc520SJung-uk Kim     return (Checksum);
3049a4bc520SJung-uk Kim }
3059a4bc520SJung-uk Kim 
3069a4bc520SJung-uk Kim 
3079a4bc520SJung-uk Kim /*******************************************************************************
3089a4bc520SJung-uk Kim  *
3099a4bc520SJung-uk Kim  * FUNCTION:    AcpiUtChecksum
3109a4bc520SJung-uk Kim  *
3119a4bc520SJung-uk Kim  * PARAMETERS:  Buffer          - Pointer to memory region to be checked
3129a4bc520SJung-uk Kim  *              Length          - Length of this memory region
3139a4bc520SJung-uk Kim  *
3149a4bc520SJung-uk Kim  * RETURN:      Checksum (UINT8)
3159a4bc520SJung-uk Kim  *
3169a4bc520SJung-uk Kim  * DESCRIPTION: Calculates circular checksum of memory region.
3179a4bc520SJung-uk Kim  *
3189a4bc520SJung-uk Kim  ******************************************************************************/
3199a4bc520SJung-uk Kim 
3209a4bc520SJung-uk Kim UINT8
3219a4bc520SJung-uk Kim AcpiUtChecksum (
3229a4bc520SJung-uk Kim     UINT8                   *Buffer,
3239a4bc520SJung-uk Kim     UINT32                  Length)
3249a4bc520SJung-uk Kim {
3259a4bc520SJung-uk Kim     UINT8                   Sum = 0;
3269a4bc520SJung-uk Kim     UINT8                   *End = Buffer + Length;
3279a4bc520SJung-uk Kim 
3289a4bc520SJung-uk Kim 
3299a4bc520SJung-uk Kim     while (Buffer < End)
3309a4bc520SJung-uk Kim     {
3319a4bc520SJung-uk Kim         Sum = (UINT8) (Sum + *(Buffer++));
3329a4bc520SJung-uk Kim     }
3339a4bc520SJung-uk Kim 
3349a4bc520SJung-uk Kim     return (Sum);
3359a4bc520SJung-uk Kim }
336