LXR linux/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 - 2021, Intel Corp.
   7 *
   8 *****************************************************************************/
   9
  10#include <acpi/acpi.h>
  11#include "accommon.h"
  12#include "actables.h"
  13
  14#define _COMPONENT          ACPI_TABLES
  15ACPI_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 ******************************************************************************/
  33acpi_status
  34acpi_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
 119unlock_and_exit:
 120        (void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
 121        return_ACPI_STATUS(status);
 122}
 123