drivers/acpi/tables/tbxfroot.c

   1 /******************************************************************************
   2  *
   3  * Module Name: tbxfroot - Find the root ACPI table (RSDT)
   4  *
   5  *****************************************************************************/
   6
   7 /******************************************************************************
   8  *
   9  * 1. Copyright Notice
  10  *
  11  * Some or all of this work - Copyright (c) 1999 - 2010, Intel Corp.
  12  * All rights reserved.
  13  *
  14  * 2. License
  15  *
  16  * 2.1. This is your license from Intel Corp. under its intellectual property
  17  * rights.  You may have additional license terms from the party that provided
  18  * you this software, covering your right to use that party's intellectual
  19  * property rights.
  20  *
  21  * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
  22  * copy of the source code appearing in this file ("Covered Code") an
  23  * irrevocable, perpetual, worldwide license under Intel's copyrights in the
  24  * base code distributed originally by Intel ("Original Intel Code") to copy,
  25  * make derivatives, distribute, use and display any portion of the Covered
  26  * Code in any form, with the right to sublicense such rights; and
  27  *
  28  * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
  29  * license (with the right to sublicense), under only those claims of Intel
  30  * patents that are infringed by the Original Intel Code, to make, use, sell,
  31  * offer to sell, and import the Covered Code and derivative works thereof
  32  * solely to the minimum extent necessary to exercise the above copyright
  33  * license, and in no event shall the patent license extend to any additions
  34  * to or modifications of the Original Intel Code.  No other license or right
  35  * is granted directly or by implication, estoppel or otherwise;
  36  *
  37  * The above copyright and patent license is granted only if the following
  38  * conditions are met:
  39  *
  40  * 3. Conditions
  41  *
  42  * 3.1. Redistribution of Source with Rights to Further Distribute Source.
  43  * Redistribution of source code of any substantial portion of the Covered
  44  * Code or modification with rights to further distribute source must include
  45  * the above Copyright Notice, the above License, this list of Conditions,
  46  * and the following Disclaimer and Export Compliance provision.  In addition,
  47  * Licensee must cause all Covered Code to which Licensee contributes to
  48  * contain a file documenting the changes Licensee made to create that Covered
  49  * Code and the date of any change.  Licensee must include in that file the
  50  * documentation of any changes made by any predecessor Licensee.  Licensee
  51  * must include a prominent statement that the modification is derived,
  52  * directly or indirectly, from Original Intel Code.
  53  *
  54  * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
  55  * Redistribution of source code of any substantial portion of the Covered
  56  * Code or modification without rights to further distribute source must
  57  * include the following Disclaimer and Export Compliance provision in the
  58  * documentation and/or other materials provided with distribution.  In
  59  * addition, Licensee may not authorize further sublicense of source of any
  60  * portion of the Covered Code, and must include terms to the effect that the
  61  * license from Licensee to its licensee is limited to the intellectual
  62  * property embodied in the software Licensee provides to its licensee, and
  63  * not to intellectual property embodied in modifications its licensee may
  64  * make.
  65  *
  66  * 3.3. Redistribution of Executable. Redistribution in executable form of any
  67  * substantial portion of the Covered Code or modification must reproduce the
  68  * above Copyright Notice, and the following Disclaimer and Export Compliance
  69  * provision in the documentation and/or other materials provided with the
  70  * distribution.
  71  *
  72  * 3.4. Intel retains all right, title, and interest in and to the Original
  73  * Intel Code.
  74  *
  75  * 3.5. Neither the name Intel nor any other trademark owned or controlled by
  76  * Intel shall be used in advertising or otherwise to promote the sale, use or
  77  * other dealings in products derived from or relating to the Covered Code
  78  * without prior written authorization from Intel.
  79  *
  80  * 4. Disclaimer and Export Compliance
  81  *
  82  * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
  83  * HERE.  ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
  84  * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT,  ASSISTANCE,
  85  * INSTALLATION, TRAINING OR OTHER SERVICES.  INTEL WILL NOT PROVIDE ANY
  86  * UPDATES, ENHANCEMENTS OR EXTENSIONS.  INTEL SPECIFICALLY DISCLAIMS ANY
  87  * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
  88  * PARTICULAR PURPOSE.
  89  *
  90  * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
  91  * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
  92  * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
  93  * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
  94  * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
  95  * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.  THESE LIMITATIONS
  96  * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
  97  * LIMITED REMEDY.
  98  *
  99  * 4.3. Licensee shall not export, either directly or indirectly, any of this
 100  * software or system incorporating such software without first obtaining any
 101  * required license or other approval from the U. S. Department of Commerce or
 102  * any other agency or department of the United States Government.  In the
 103  * event Licensee exports any such software from the United States or
 104  * re-exports any such software from a foreign destination, Licensee shall
 105  * ensure that the distribution and export/re-export of the software is in
 106  * compliance with all laws, regulations, orders, or other restrictions of the
 107  * U.S. Export Administration Regulations. Licensee agrees that neither it nor
 108  * any of its subsidiaries will export/re-export any technical data, process,
 109  * software, or service, directly or indirectly, to any country for which the
 110  * United States government or any agency thereof requires an export license,
 111  * other governmental approval, or letter of assurance, without first obtaining
 112  * such license, approval or letter.
 113  *
 114  *****************************************************************************/
 115
 116 #define __TBXFROOT_C__
 117
 118 #include "acpi.h"
 119 #include "accommon.h"
 120 #include "actables.h"
 121
 122
 123 #define _COMPONENT          ACPI_TABLES
 124         ACPI_MODULE_NAME    ("tbxfroot")
 125
 126 /* Local prototypes */
 127
 128 static UINT8 *
 129 AcpiTbScanMemoryForRsdp (
 130     UINT8                   *StartAddress,
 131     UINT32                  Length);
 132
 133 static ACPI_STATUS
 134 AcpiTbValidateRsdp (
 135     ACPI_TABLE_RSDP         *Rsdp);
 136
 137
 138 /*******************************************************************************
 139  *
 140  * FUNCTION:    AcpiTbValidateRsdp
 141  *
 142  * PARAMETERS:  Rsdp                - Pointer to unvalidated RSDP
 143  *
 144  * RETURN:      Status
 145  *
 146  * DESCRIPTION: Validate the RSDP (ptr)
 147  *
 148  ******************************************************************************/
 149
 150 static ACPI_STATUS
 151 AcpiTbValidateRsdp (
 152     ACPI_TABLE_RSDP         *Rsdp)
 153 {
 154     ACPI_FUNCTION_ENTRY ();
 155
 156
 157     /*
 158      * The signature and checksum must both be correct
 159      *
 160      * Note: Sometimes there exists more than one RSDP in memory; the valid
 161      * RSDP has a valid checksum, all others have an invalid checksum.
 162      */
 163     if (ACPI_STRNCMP ((char *) Rsdp, ACPI_SIG_RSDP,
 164             sizeof (ACPI_SIG_RSDP)-1) != 0)
 165     {
 166         /* Nope, BAD Signature */
 167
 168         return (AE_BAD_SIGNATURE);
 169     }
 170
 171     /* Check the standard checksum */
 172
 173     if (AcpiTbChecksum ((UINT8 *) Rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0)
 174     {
 175         return (AE_BAD_CHECKSUM);
 176     }
 177
 178     /* Check extended checksum if table version >= 2 */
 179
 180     if ((Rsdp->Revision >= 2) &&
 181         (AcpiTbChecksum ((UINT8 *) Rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) != 0))
 182     {
 183         return (AE_BAD_CHECKSUM);
 184     }
 185
 186     return (AE_OK);
 187 }
 188
 189
 190 /*******************************************************************************
 191  *
 192  * FUNCTION:    AcpiFindRootPointer
 193  *
 194  * PARAMETERS:  TableAddress            - Where the table pointer is returned
 195  *
 196  * RETURN:      Status, RSDP physical address
 197  *
 198  * DESCRIPTION: Search lower 1Mbyte of memory for the root system descriptor
 199  *              pointer structure.  If it is found, set *RSDP to point to it.
 200  *
 201  * NOTE1:       The RSDP must be either in the first 1K of the Extended
 202  *              BIOS Data Area or between E0000 and FFFFF (From ACPI Spec.)
 203  *              Only a 32-bit physical address is necessary.
 204  *
 205  * NOTE2:       This function is always available, regardless of the
 206  *              initialization state of the rest of ACPI.
 207  *
 208  ******************************************************************************/
 209
 210 ACPI_STATUS
 211 AcpiFindRootPointer (
 212     ACPI_SIZE               *TableAddress)
 213 {
 214     UINT8                   *TablePtr;
 215     UINT8                   *MemRover;
 216     UINT32                  PhysicalAddress;
 217
 218
 219     ACPI_FUNCTION_TRACE (AcpiFindRootPointer);
 220
 221
 222     /* 1a) Get the location of the Extended BIOS Data Area (EBDA) */
 223
 224     TablePtr = AcpiOsMapMemory (
 225                 (ACPI_PHYSICAL_ADDRESS) ACPI_EBDA_PTR_LOCATION,
 226                 ACPI_EBDA_PTR_LENGTH);
 227     if (!TablePtr)
 228     {
 229         ACPI_ERROR ((AE_INFO,
 230             "Could not map memory at 0x%8.8X for length %u",
 231             ACPI_EBDA_PTR_LOCATION, ACPI_EBDA_PTR_LENGTH));
 232
 233         return_ACPI_STATUS (AE_NO_MEMORY);
 234     }
 235
 236     ACPI_MOVE_16_TO_32 (&PhysicalAddress, TablePtr);
 237
 238     /* Convert segment part to physical address */
 239
 240     PhysicalAddress <<= 4;
 241     AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_PTR_LENGTH);
 242
 243     /* EBDA present? */
 244
 245     if (PhysicalAddress > 0x400)
 246     {
 247         /*
 248          * 1b) Search EBDA paragraphs (EBDA is required to be a
 249          *     minimum of 1K length)
 250          */
 251         TablePtr = AcpiOsMapMemory (
 252                     (ACPI_PHYSICAL_ADDRESS) PhysicalAddress,
 253                     ACPI_EBDA_WINDOW_SIZE);
 254         if (!TablePtr)
 255         {
 256             ACPI_ERROR ((AE_INFO,
 257                 "Could not map memory at 0x%8.8X for length %u",
 258                 PhysicalAddress, ACPI_EBDA_WINDOW_SIZE));
 259
 260             return_ACPI_STATUS (AE_NO_MEMORY);
 261         }
 262
 263         MemRover = AcpiTbScanMemoryForRsdp (TablePtr, ACPI_EBDA_WINDOW_SIZE);
 264         AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_WINDOW_SIZE);
 265
 266         if (MemRover)
 267         {
 268             /* Return the physical address */
 269
 270             PhysicalAddress += (UINT32) ACPI_PTR_DIFF (MemRover, TablePtr);
 271
 272             *TableAddress = PhysicalAddress;
 273             return_ACPI_STATUS (AE_OK);
 274         }
 275     }
 276
 277     /*
 278      * 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh
 279      */
 280     TablePtr = AcpiOsMapMemory (
 281                 (ACPI_PHYSICAL_ADDRESS) ACPI_HI_RSDP_WINDOW_BASE,
 282                 ACPI_HI_RSDP_WINDOW_SIZE);
 283
 284     if (!TablePtr)
 285     {
 286         ACPI_ERROR ((AE_INFO,
 287             "Could not map memory at 0x%8.8X for length %u",
 288             ACPI_HI_RSDP_WINDOW_BASE, ACPI_HI_RSDP_WINDOW_SIZE));
 289
 290         return_ACPI_STATUS (AE_NO_MEMORY);
 291     }
 292
 293     MemRover = AcpiTbScanMemoryForRsdp (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE);
 294     AcpiOsUnmapMemory (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE);
 295
 296     if (MemRover)
 297     {
 298         /* Return the physical address */
 299
 300         PhysicalAddress = (UINT32)
 301             (ACPI_HI_RSDP_WINDOW_BASE + ACPI_PTR_DIFF (MemRover, TablePtr));
 302
 303         *TableAddress = PhysicalAddress;
 304         return_ACPI_STATUS (AE_OK);
 305     }
 306
 307     /* A valid RSDP was not found */
 308
 309     ACPI_ERROR ((AE_INFO, "A valid RSDP was not found"));
 310     return_ACPI_STATUS (AE_NOT_FOUND);
 311 }
 312
 313 ACPI_EXPORT_SYMBOL (AcpiFindRootPointer)
 314
 315
 316 /*******************************************************************************
 317  *
 318  * FUNCTION:    AcpiTbScanMemoryForRsdp
 319  *
 320  * PARAMETERS:  StartAddress        - Starting pointer for search
 321  *              Length              - Maximum length to search
 322  *
 323  * RETURN:      Pointer to the RSDP if found, otherwise NULL.
 324  *
 325  * DESCRIPTION: Search a block of memory for the RSDP signature
 326  *
 327  ******************************************************************************/
 328
 329 static UINT8 *
 330 AcpiTbScanMemoryForRsdp (
 331     UINT8                   *StartAddress,
 332     UINT32                  Length)
 333 {
 334     ACPI_STATUS             Status;
 335     UINT8                   *MemRover;
 336     UINT8                   *EndAddress;
 337
 338
 339     ACPI_FUNCTION_TRACE (TbScanMemoryForRsdp);
 340
 341
 342     EndAddress = StartAddress + Length;
 343
 344     /* Search from given start address for the requested length */
 345
 346     for (MemRover = StartAddress; MemRover < EndAddress;
 347          MemRover += ACPI_RSDP_SCAN_STEP)
 348     {
 349         /* The RSDP signature and checksum must both be correct */
 350
 351         Status = AcpiTbValidateRsdp (ACPI_CAST_PTR (ACPI_TABLE_RSDP, MemRover));
 352         if (ACPI_SUCCESS (Status))
 353         {
 354             /* Sig and checksum valid, we have found a real RSDP */
 355
 356             ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
 357                 "RSDP located at physical address %p\n", MemRover));
 358             return_PTR (MemRover);
 359         }
 360
 361         /* No sig match or bad checksum, keep searching */
 362     }
 363
 364     /* Searched entire block, no RSDP was found */
 365
 366     ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
 367         "Searched entire block from %p, valid RSDP was not found\n",
 368         StartAddress));
 369     return_PTR (NULL);
 370 }
 371