drivers/acpi/acpica/tbfind.c

   1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
   2 /******************************************************************************
   3  *
   4  * Module Name: tbfind   - find table
   5  *
   6  * Copyright (C) 2000 - 2020, Intel Corp.
   7  *
   8  *****************************************************************************/
   9
  10 #include <acpi/acpi.h>
  11 #include "accommon.h"
  12 #include "actables.h"
  13
  14 #define _COMPONENT          ACPI_TABLES
  15 ACPI_MODULE_NAME("tbfind")
  16
  17 /*******************************************************************************
  18  *
  19  * FUNCTION:    acpi_tb_find_table
  20  *
  21  * PARAMETERS:  signature           - String with ACPI table signature
  22  *              oem_id              - String with the table OEM ID
  23  *              oem_table_id        - String with the OEM Table ID
  24  *              table_index         - Where the table index is returned
  25  *
  26  * RETURN:      Status and table index
  27  *
  28  * DESCRIPTION: Find an ACPI table (in the RSDT/XSDT) that matches the
  29  *              Signature, OEM ID and OEM Table ID. Returns an index that can
  30  *              be used to get the table header or entire table.
  31  *
  32  ******************************************************************************/
  33 acpi_status
  34 acpi_tb_find_table(char *signature,
  35                    char *oem_id, char *oem_table_id, u32 *table_index)
  36 {
  37         acpi_status status = AE_OK;
  38         struct acpi_table_header header;
  39         u32 i;
  40
  41         ACPI_FUNCTION_TRACE(tb_find_table);
  42
  43         /* Validate the input table signature */
  44
  45         if (!acpi_ut_valid_nameseg(signature)) {
  46                 return_ACPI_STATUS(AE_BAD_SIGNATURE);
  47         }
  48
  49         /* Don't allow the OEM strings to be too long */
  50
  51         if ((strlen(oem_id) > ACPI_OEM_ID_SIZE) ||
  52             (strlen(oem_table_id) > ACPI_OEM_TABLE_ID_SIZE)) {
  53                 return_ACPI_STATUS(AE_AML_STRING_LIMIT);
  54         }
  55
  56         /* Normalize the input strings */
  57
  58         memset(&header, 0, sizeof(struct acpi_table_header));
  59         ACPI_COPY_NAMESEG(header.signature, signature);
  60         strncpy(header.oem_id, oem_id, ACPI_OEM_ID_SIZE);
  61         strncpy(header.oem_table_id, oem_table_id, ACPI_OEM_TABLE_ID_SIZE);
  62
  63         /* Search for the table */
  64
  65         (void)acpi_ut_acquire_mutex(ACPI_MTX_TABLES);
  66         for (i = 0; i < acpi_gbl_root_table_list.current_table_count; ++i) {
  67                 if (memcmp(&(acpi_gbl_root_table_list.tables[i].signature),
  68                            header.signature, ACPI_NAMESEG_SIZE)) {
  69
  70                         /* Not the requested table */
  71
  72                         continue;
  73                 }
  74
  75                 /* Table with matching signature has been found */
  76
  77                 if (!acpi_gbl_root_table_list.tables[i].pointer) {
  78
  79                         /* Table is not currently mapped, map it */
  80
  81                         status =
  82                             acpi_tb_validate_table(&acpi_gbl_root_table_list.
  83                                                    tables[i]);
  84                         if (ACPI_FAILURE(status)) {
  85                                 goto unlock_and_exit;
  86                         }
  87
  88                         if (!acpi_gbl_root_table_list.tables[i].pointer) {
  89                                 continue;
  90                         }
  91                 }
  92
  93                 /* Check for table match on all IDs */
  94
  95                 if (!memcmp
  96                     (acpi_gbl_root_table_list.tables[i].pointer->signature,
  97                      header.signature, ACPI_NAMESEG_SIZE) && (!oem_id[0]
  98                                                               ||
  99                                                               !memcmp
 100                                                               (acpi_gbl_root_table_list.
 101                                                                tables[i].
 102                                                                pointer->oem_id,
 103                                                                header.oem_id,
 104                                                                ACPI_OEM_ID_SIZE))
 105                     && (!oem_table_id[0]
 106                         || !memcmp(acpi_gbl_root_table_list.tables[i].pointer->
 107                                    oem_table_id, header.oem_table_id,
 108                                    ACPI_OEM_TABLE_ID_SIZE))) {
 109                         *table_index = i;
 110
 111                         ACPI_DEBUG_PRINT((ACPI_DB_TABLES,
 112                                           "Found table [%4.4s]\n",
 113                                           header.signature));
 114                         goto unlock_and_exit;
 115                 }
 116         }
 117         status = AE_NOT_FOUND;
 118
 119 unlock_and_exit:
 120         (void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
 121         return_ACPI_STATUS(status);
 122 }