arch/all-pc/acpica/source/components/tables/tbxfroot.c

   1 /******************************************************************************
   2  *
   3  * Module Name: tbxfroot - Find the root ACPI table (RSDT)
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2013, Intel Corp.
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions, and the following disclaimer,
  16  *    without modification.
  17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  18  *    substantially similar to the "NO WARRANTY" disclaimer below
  19  *    ("Disclaimer") and any redistribution must be conditioned upon
  20  *    including a substantially similar Disclaimer requirement for further
  21  *    binary redistribution.
  22  * 3. Neither the names of the above-listed copyright holders nor the names
  23  *    of any contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * Alternatively, this software may be distributed under the terms of the
  27  * GNU General Public License ("GPL") version 2 as published by the Free
  28  * Software Foundation.
  29  *
  30  * NO WARRANTY
  31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  41  * POSSIBILITY OF SUCH DAMAGES.
  42  */
  43
  44 #define __TBXFROOT_C__
  45
  46 #include "acpi.h"
  47 #include "accommon.h"
  48 #include "actables.h"
  49
  50
  51 #define _COMPONENT          ACPI_TABLES
  52         ACPI_MODULE_NAME    ("tbxfroot")
  53
  54
  55 /*******************************************************************************
  56  *
  57  * FUNCTION:    AcpiTbValidateRsdp
  58  *
  59  * PARAMETERS:  Rsdp                - Pointer to unvalidated RSDP
  60  *
  61  * RETURN:      Status
  62  *
  63  * DESCRIPTION: Validate the RSDP (ptr)
  64  *
  65  ******************************************************************************/
  66
  67 ACPI_STATUS
  68 AcpiTbValidateRsdp (
  69     ACPI_TABLE_RSDP         *Rsdp)
  70 {
  71
  72     /*
  73      * The signature and checksum must both be correct
  74      *
  75      * Note: Sometimes there exists more than one RSDP in memory; the valid
  76      * RSDP has a valid checksum, all others have an invalid checksum.
  77      */
  78     if (!ACPI_VALIDATE_RSDP_SIG (Rsdp->Signature))
  79     {
  80         /* Nope, BAD Signature */
  81
  82         return (AE_BAD_SIGNATURE);
  83     }
  84
  85     /* Check the standard checksum */
  86
  87     if (AcpiTbChecksum ((UINT8 *) Rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0)
  88     {
  89         return (AE_BAD_CHECKSUM);
  90     }
  91
  92     /* Check extended checksum if table version >= 2 */
  93
  94     if ((Rsdp->Revision >= 2) &&
  95         (AcpiTbChecksum ((UINT8 *) Rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) != 0))
  96     {
  97         return (AE_BAD_CHECKSUM);
  98     }
  99
 100     return (AE_OK);
 101 }
 102
 103
 104 /*******************************************************************************
 105  *
 106  * FUNCTION:    AcpiFindRootPointer
 107  *
 108  * PARAMETERS:  TableAddress            - Where the table pointer is returned
 109  *
 110  * RETURN:      Status, RSDP physical address
 111  *
 112  * DESCRIPTION: Search lower 1Mbyte of memory for the root system descriptor
 113  *              pointer structure. If it is found, set *RSDP to point to it.
 114  *
 115  * NOTE1:       The RSDP must be either in the first 1K of the Extended
 116  *              BIOS Data Area or between E0000 and FFFFF (From ACPI Spec.)
 117  *              Only a 32-bit physical address is necessary.
 118  *
 119  * NOTE2:       This function is always available, regardless of the
 120  *              initialization state of the rest of ACPI.
 121  *
 122  ******************************************************************************/
 123
 124 ACPI_STATUS
 125 AcpiFindRootPointer (
 126     ACPI_SIZE               *TableAddress)
 127 {
 128     UINT8                   *TablePtr;
 129     UINT8                   *MemRover;
 130     UINT32                  PhysicalAddress;
 131
 132
 133     ACPI_FUNCTION_TRACE (AcpiFindRootPointer);
 134
 135
 136     /* 1a) Get the location of the Extended BIOS Data Area (EBDA) */
 137
 138     TablePtr = AcpiOsMapMemory (
 139                 (ACPI_PHYSICAL_ADDRESS) ACPI_EBDA_PTR_LOCATION,
 140                 ACPI_EBDA_PTR_LENGTH);
 141     if (!TablePtr)
 142     {
 143         ACPI_ERROR ((AE_INFO,
 144             "Could not map memory at 0x%8.8X for length %u",
 145             ACPI_EBDA_PTR_LOCATION, ACPI_EBDA_PTR_LENGTH));
 146
 147         return_ACPI_STATUS (AE_NO_MEMORY);
 148     }
 149
 150     ACPI_MOVE_16_TO_32 (&PhysicalAddress, TablePtr);
 151
 152     /* Convert segment part to physical address */
 153
 154     PhysicalAddress <<= 4;
 155     AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_PTR_LENGTH);
 156
 157     /* EBDA present? */
 158
 159     if (PhysicalAddress > 0x400)
 160     {
 161         /*
 162          * 1b) Search EBDA paragraphs (EBDA is required to be a
 163          *     minimum of 1K length)
 164          */
 165         TablePtr = AcpiOsMapMemory (
 166                     (ACPI_PHYSICAL_ADDRESS) PhysicalAddress,
 167                     ACPI_EBDA_WINDOW_SIZE);
 168         if (!TablePtr)
 169         {
 170             ACPI_ERROR ((AE_INFO,
 171                 "Could not map memory at 0x%8.8X for length %u",
 172                 PhysicalAddress, ACPI_EBDA_WINDOW_SIZE));
 173
 174             return_ACPI_STATUS (AE_NO_MEMORY);
 175         }
 176
 177         MemRover = AcpiTbScanMemoryForRsdp (TablePtr, ACPI_EBDA_WINDOW_SIZE);
 178         AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_WINDOW_SIZE);
 179
 180         if (MemRover)
 181         {
 182             /* Return the physical address */
 183
 184             PhysicalAddress += (UINT32) ACPI_PTR_DIFF (MemRover, TablePtr);
 185
 186             *TableAddress = PhysicalAddress;
 187             return_ACPI_STATUS (AE_OK);
 188         }
 189     }
 190
 191     /*
 192      * 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh
 193      */
 194     TablePtr = AcpiOsMapMemory (
 195                 (ACPI_PHYSICAL_ADDRESS) ACPI_HI_RSDP_WINDOW_BASE,
 196                 ACPI_HI_RSDP_WINDOW_SIZE);
 197
 198     if (!TablePtr)
 199     {
 200         ACPI_ERROR ((AE_INFO,
 201             "Could not map memory at 0x%8.8X for length %u",
 202             ACPI_HI_RSDP_WINDOW_BASE, ACPI_HI_RSDP_WINDOW_SIZE));
 203
 204         return_ACPI_STATUS (AE_NO_MEMORY);
 205     }
 206
 207     MemRover = AcpiTbScanMemoryForRsdp (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE);
 208     AcpiOsUnmapMemory (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE);
 209
 210     if (MemRover)
 211     {
 212         /* Return the physical address */
 213
 214         PhysicalAddress = (UINT32)
 215             (ACPI_HI_RSDP_WINDOW_BASE + ACPI_PTR_DIFF (MemRover, TablePtr));
 216
 217         *TableAddress = PhysicalAddress;
 218         return_ACPI_STATUS (AE_OK);
 219     }
 220
 221     /* A valid RSDP was not found */
 222
 223     ACPI_BIOS_ERROR ((AE_INFO, "A valid RSDP was not found"));
 224     return_ACPI_STATUS (AE_NOT_FOUND);
 225 }
 226
 227 ACPI_EXPORT_SYMBOL (AcpiFindRootPointer)
 228
 229
 230 /*******************************************************************************
 231  *
 232  * FUNCTION:    AcpiTbScanMemoryForRsdp
 233  *
 234  * PARAMETERS:  StartAddress        - Starting pointer for search
 235  *              Length              - Maximum length to search
 236  *
 237  * RETURN:      Pointer to the RSDP if found, otherwise NULL.
 238  *
 239  * DESCRIPTION: Search a block of memory for the RSDP signature
 240  *
 241  ******************************************************************************/
 242
 243 UINT8 *
 244 AcpiTbScanMemoryForRsdp (
 245     UINT8                   *StartAddress,
 246     UINT32                  Length)
 247 {
 248     ACPI_STATUS             Status;
 249     UINT8                   *MemRover;
 250     UINT8                   *EndAddress;
 251
 252
 253     ACPI_FUNCTION_TRACE (TbScanMemoryForRsdp);
 254
 255
 256     EndAddress = StartAddress + Length;
 257
 258     /* Search from given start address for the requested length */
 259
 260     for (MemRover = StartAddress; MemRover < EndAddress;
 261          MemRover += ACPI_RSDP_SCAN_STEP)
 262     {
 263         /* The RSDP signature and checksum must both be correct */
 264
 265         Status = AcpiTbValidateRsdp (ACPI_CAST_PTR (ACPI_TABLE_RSDP, MemRover));
 266         if (ACPI_SUCCESS (Status))
 267         {
 268             /* Sig and checksum valid, we have found a real RSDP */
 269
 270             ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
 271                 "RSDP located at physical address %p\n", MemRover));
 272             return_PTR (MemRover);
 273         }
 274
 275         /* No sig match or bad checksum, keep searching */
 276     }
 277
 278     /* Searched entire block, no RSDP was found */
 279
 280     ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
 281         "Searched entire block from %p, valid RSDP was not found\n",
 282         StartAddress));
 283     return_PTR (NULL);
 284 }