drivers/acpica/tbxfroot.c

0001 /******************************************************************************
0002  *
0003  * Module Name: tbxfroot - Find the root ACPI table (RSDT)
0004  *
0005  *****************************************************************************/
0006
0007 /******************************************************************************
0008  *
0009  * 1. Copyright Notice
0010  *
0011  * Some or all of this work - Copyright (c) 1999 - 2009, Intel Corp.
0012  * All rights reserved.
0013  *
0014  * 2. License
0015  *
0016  * 2.1. This is your license from Intel Corp. under its intellectual property
0017  * rights.  You may have additional license terms from the party that provided
0018  * you this software, covering your right to use that party's intellectual
0019  * property rights.
0020  *
0021  * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
0022  * copy of the source code appearing in this file ("Covered Code") an
0023  * irrevocable, perpetual, worldwide license under Intel's copyrights in the
0024  * base code distributed originally by Intel ("Original Intel Code") to copy,
0025  * make derivatives, distribute, use and display any portion of the Covered
0026  * Code in any form, with the right to sublicense such rights; and
0027  *
0028  * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
0029  * license (with the right to sublicense), under only those claims of Intel
0030  * patents that are infringed by the Original Intel Code, to make, use, sell,
0031  * offer to sell, and import the Covered Code and derivative works thereof
0032  * solely to the minimum extent necessary to exercise the above copyright
0033  * license, and in no event shall the patent license extend to any additions
0034  * to or modifications of the Original Intel Code.  No other license or right
0035  * is granted directly or by implication, estoppel or otherwise;
0036  *
0037  * The above copyright and patent license is granted only if the following
0038  * conditions are met:
0039  *
0040  * 3. Conditions
0041  *
0042  * 3.1. Redistribution of Source with Rights to Further Distribute Source.
0043  * Redistribution of source code of any substantial portion of the Covered
0044  * Code or modification with rights to further distribute source must include
0045  * the above Copyright Notice, the above License, this list of Conditions,
0046  * and the following Disclaimer and Export Compliance provision.  In addition,
0047  * Licensee must cause all Covered Code to which Licensee contributes to
0048  * contain a file documenting the changes Licensee made to create that Covered
0049  * Code and the date of any change.  Licensee must include in that file the
0050  * documentation of any changes made by any predecessor Licensee.  Licensee
0051  * must include a prominent statement that the modification is derived,
0052  * directly or indirectly, from Original Intel Code.
0053  *
0054  * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
0055  * Redistribution of source code of any substantial portion of the Covered
0056  * Code or modification without rights to further distribute source must
0057  * include the following Disclaimer and Export Compliance provision in the
0058  * documentation and/or other materials provided with distribution.  In
0059  * addition, Licensee may not authorize further sublicense of source of any
0060  * portion of the Covered Code, and must include terms to the effect that the
0061  * license from Licensee to its licensee is limited to the intellectual
0062  * property embodied in the software Licensee provides to its licensee, and
0063  * not to intellectual property embodied in modifications its licensee may
0064  * make.
0065  *
0066  * 3.3. Redistribution of Executable. Redistribution in executable form of any
0067  * substantial portion of the Covered Code or modification must reproduce the
0068  * above Copyright Notice, and the following Disclaimer and Export Compliance
0069  * provision in the documentation and/or other materials provided with the
0070  * distribution.
0071  *
0072  * 3.4. Intel retains all right, title, and interest in and to the Original
0073  * Intel Code.
0074  *
0075  * 3.5. Neither the name Intel nor any other trademark owned or controlled by
0076  * Intel shall be used in advertising or otherwise to promote the sale, use or
0077  * other dealings in products derived from or relating to the Covered Code
0078  * without prior written authorization from Intel.
0079  *
0080  * 4. Disclaimer and Export Compliance
0081  *
0082  * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
0083  * HERE.  ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
0084  * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT,  ASSISTANCE,
0085  * INSTALLATION, TRAINING OR OTHER SERVICES.  INTEL WILL NOT PROVIDE ANY
0086  * UPDATES, ENHANCEMENTS OR EXTENSIONS.  INTEL SPECIFICALLY DISCLAIMS ANY
0087  * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
0088  * PARTICULAR PURPOSE.
0089  *
0090  * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
0091  * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
0092  * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
0093  * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
0094  * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
0095  * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.  THESE LIMITATIONS
0096  * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
0097  * LIMITED REMEDY.
0098  *
0099  * 4.3. Licensee shall not export, either directly or indirectly, any of this
0100  * software or system incorporating such software without first obtaining any
0101  * required license or other approval from the U. S. Department of Commerce or
0102  * any other agency or department of the United States Government.  In the
0103  * event Licensee exports any such software from the United States or
0104  * re-exports any such software from a foreign destination, Licensee shall
0105  * ensure that the distribution and export/re-export of the software is in
0106  * compliance with all laws, regulations, orders, or other restrictions of the
0107  * U.S. Export Administration Regulations. Licensee agrees that neither it nor
0108  * any of its subsidiaries will export/re-export any technical data, process,
0109  * software, or service, directly or indirectly, to any country for which the
0110  * United States government or any agency thereof requires an export license,
0111  * other governmental approval, or letter of assurance, without first obtaining
0112  * such license, approval or letter.
0113  *
0114  *****************************************************************************/
0115
0116 #define __TBXFROOT_C__
0117
0118 #include "acpi.h"
0119 #include "accommon.h"
0120 #include "actables.h"
0121
0122
0123 #define _COMPONENT          ACPI_TABLES
0124         ACPI_MODULE_NAME    ("tbxfroot")
0125
0126 /* Local prototypes */
0127
0128 static UINT8 *
0129 AcpiTbScanMemoryForRsdp (
0130     UINT8                   *StartAddress,
0131     UINT32                  Length);
0132
0133 static ACPI_STATUS
0134 AcpiTbValidateRsdp (
0135     ACPI_TABLE_RSDP         *Rsdp);
0136
0137
0138 /*******************************************************************************
0139  *
0140  * FUNCTION:    AcpiTbValidateRsdp
0141  *
0142  * PARAMETERS:  Rsdp                - Pointer to unvalidated RSDP
0143  *
0144  * RETURN:      Status
0145  *
0146  * DESCRIPTION: Validate the RSDP (ptr)
0147  *
0148  ******************************************************************************/
0149
0150 static ACPI_STATUS
0151 AcpiTbValidateRsdp (
0152     ACPI_TABLE_RSDP         *Rsdp)
0153 {
0154     ACPI_FUNCTION_ENTRY ();
0155
0156
0157     /*
0158      * The signature and checksum must both be correct
0159      *
0160      * Note: Sometimes there exists more than one RSDP in memory; the valid
0161      * RSDP has a valid checksum, all others have an invalid checksum.
0162      */
0163     if (ACPI_STRNCMP ((char *) Rsdp, ACPI_SIG_RSDP,
0164             sizeof (ACPI_SIG_RSDP)-1) != 0)
0165     {
0166         /* Nope, BAD Signature */
0167
0168         return (AE_BAD_SIGNATURE);
0169     }
0170
0171     /* Check the standard checksum */
0172
0173     if (AcpiTbChecksum ((UINT8 *) Rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0)
0174     {
0175         return (AE_BAD_CHECKSUM);
0176     }
0177
0178     /* Check extended checksum if table version >= 2 */
0179
0180     if ((Rsdp->Revision >= 2) &&
0181         (AcpiTbChecksum ((UINT8 *) Rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) != 0))
0182     {
0183         return (AE_BAD_CHECKSUM);
0184     }
0185
0186     return (AE_OK);
0187 }
0188
0189
0190 /*******************************************************************************
0191  *
0192  * FUNCTION:    AcpiFindRootPointer
0193  *
0194  * PARAMETERS:  TableAddress            - Where the table pointer is returned
0195  *
0196  * RETURN:      Status, RSDP physical address
0197  *
0198  * DESCRIPTION: Search lower 1Mbyte of memory for the root system descriptor
0199  *              pointer structure.  If it is found, set *RSDP to point to it.
0200  *
0201  * NOTE1:       The RSDP must be either in the first 1K of the Extended
0202  *              BIOS Data Area or between E0000 and FFFFF (From ACPI Spec.)
0203  *              Only a 32-bit physical address is necessary.
0204  *
0205  * NOTE2:       This function is always available, regardless of the
0206  *              initialization state of the rest of ACPI.
0207  *
0208  ******************************************************************************/
0209
0210 ACPI_STATUS
0211 AcpiFindRootPointer (
0212     ACPI_SIZE               *TableAddress)
0213 {
0214     UINT8                   *TablePtr;
0215     UINT8                   *MemRover;
0216     UINT32                  PhysicalAddress;
0217
0218
0219     ACPI_FUNCTION_TRACE (AcpiFindRootPointer);
0220
0221
0222     /* 1a) Get the location of the Extended BIOS Data Area (EBDA) */
0223
0224     TablePtr = AcpiOsMapMemory (
0225                 (ACPI_PHYSICAL_ADDRESS) ACPI_EBDA_PTR_LOCATION,
0226                 ACPI_EBDA_PTR_LENGTH);
0227     if (!TablePtr)
0228     {
0229         ACPI_ERROR ((AE_INFO,
0230             "Could not map memory at %8.8X for length %X",
0231             ACPI_EBDA_PTR_LOCATION, ACPI_EBDA_PTR_LENGTH));
0232
0233         return_ACPI_STATUS (AE_NO_MEMORY);
0234     }
0235
0236     ACPI_MOVE_16_TO_32 (&PhysicalAddress, TablePtr);
0237
0238     /* Convert segment part to physical address */
0239
0240     PhysicalAddress <<= 4;
0241     AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_PTR_LENGTH);
0242
0243     /* EBDA present? */
0244
0245     if (PhysicalAddress > 0x400)
0246     {
0247         /*
0248          * 1b) Search EBDA paragraphs (EBDA is required to be a
0249          *     minimum of 1K length)
0250          */
0251         TablePtr = AcpiOsMapMemory (
0252                     (ACPI_PHYSICAL_ADDRESS) PhysicalAddress,
0253                     ACPI_EBDA_WINDOW_SIZE);
0254         if (!TablePtr)
0255         {
0256             ACPI_ERROR ((AE_INFO,
0257                 "Could not map memory at %8.8X for length %X",
0258                 PhysicalAddress, ACPI_EBDA_WINDOW_SIZE));
0259
0260             return_ACPI_STATUS (AE_NO_MEMORY);
0261         }
0262
0263         MemRover = AcpiTbScanMemoryForRsdp (TablePtr, ACPI_EBDA_WINDOW_SIZE);
0264         AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_WINDOW_SIZE);
0265
0266         if (MemRover)
0267         {
0268             /* Return the physical address */
0269
0270             PhysicalAddress += (UINT32) ACPI_PTR_DIFF (MemRover, TablePtr);
0271
0272             *TableAddress = PhysicalAddress;
0273             return_ACPI_STATUS (AE_OK);
0274         }
0275     }
0276
0277     /*
0278      * 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh
0279      */
0280     TablePtr = AcpiOsMapMemory (
0281                 (ACPI_PHYSICAL_ADDRESS) ACPI_HI_RSDP_WINDOW_BASE,
0282                 ACPI_HI_RSDP_WINDOW_SIZE);
0283
0284     if (!TablePtr)
0285     {
0286         ACPI_ERROR ((AE_INFO,
0287             "Could not map memory at %8.8X for length %X",
0288             ACPI_HI_RSDP_WINDOW_BASE, ACPI_HI_RSDP_WINDOW_SIZE));
0289
0290         return_ACPI_STATUS (AE_NO_MEMORY);
0291     }
0292
0293     MemRover = AcpiTbScanMemoryForRsdp (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE);
0294     AcpiOsUnmapMemory (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE);
0295
0296     if (MemRover)
0297     {
0298         /* Return the physical address */
0299
0300         PhysicalAddress = (UINT32)
0301             (ACPI_HI_RSDP_WINDOW_BASE + ACPI_PTR_DIFF (MemRover, TablePtr));
0302
0303         *TableAddress = PhysicalAddress;
0304         return_ACPI_STATUS (AE_OK);
0305     }
0306
0307     /* A valid RSDP was not found */
0308
0309     ACPI_ERROR ((AE_INFO, "A valid RSDP was not found"));
0310     return_ACPI_STATUS (AE_NOT_FOUND);
0311 }
0312
0313 ACPI_EXPORT_SYMBOL (AcpiFindRootPointer)
0314
0315
0316 /*******************************************************************************
0317  *
0318  * FUNCTION:    AcpiTbScanMemoryForRsdp
0319  *
0320  * PARAMETERS:  StartAddress        - Starting pointer for search
0321  *              Length              - Maximum length to search
0322  *
0323  * RETURN:      Pointer to the RSDP if found, otherwise NULL.
0324  *
0325  * DESCRIPTION: Search a block of memory for the RSDP signature
0326  *
0327  ******************************************************************************/
0328
0329 static UINT8 *
0330 AcpiTbScanMemoryForRsdp (
0331     UINT8                   *StartAddress,
0332     UINT32                  Length)
0333 {
0334     ACPI_STATUS             Status;
0335     UINT8                   *MemRover;
0336     UINT8                   *EndAddress;
0337
0338
0339     ACPI_FUNCTION_TRACE (TbScanMemoryForRsdp);
0340
0341
0342     EndAddress = StartAddress + Length;
0343
0344     /* Search from given start address for the requested length */
0345
0346     for (MemRover = StartAddress; MemRover < EndAddress;
0347          MemRover += ACPI_RSDP_SCAN_STEP)
0348     {
0349         /* The RSDP signature and checksum must both be correct */
0350
0351         Status = AcpiTbValidateRsdp (ACPI_CAST_PTR (ACPI_TABLE_RSDP, MemRover));
0352         if (ACPI_SUCCESS (Status))
0353         {
0354             /* Sig and checksum valid, we have found a real RSDP */
0355
0356             ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
0357                 "RSDP located at physical address %p\n", MemRover));
0358             return_PTR (MemRover);
0359         }
0360
0361         /* No sig match or bad checksum, keep searching */
0362     }
0363
0364     /* Searched entire block, no RSDP was found */
0365
0366     ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
0367         "Searched entire block from %p, valid RSDP was not found\n",
0368         StartAddress));
0369     return_PTR (NULL);
0370 }
0371