IntelFrameworkPkg/Library/FrameworkUefiLib/Acpi.c

   1 /** @file
   2   This module provides help function for finding ACPI table.
   3
   4   Copyright (c) 2018, Intel Corporation. All rights reserved.<BR>
   5   SPDX-License-Identifier: BSD-2-Clause-Patent
   6
   7 **/
   8
   9 #include "UefiLibInternal.h"
  10 #include <IndustryStandard/Acpi.h>
  11
  12 /**
  13   This function locates next ACPI table in XSDT/RSDT based on Signature and
  14   previous returned Table.
  15
  16   If PreviousTable is NULL:
  17   This function will locate the first ACPI table in XSDT/RSDT based on
  18   Signature in gEfiAcpi20TableGuid system configuration table first, and then
  19   gEfiAcpi10TableGuid system configuration table.
  20   This function will locate in XSDT first, and then RSDT.
  21   For DSDT, this function will locate XDsdt in FADT first, and then Dsdt in
  22   FADT.
  23   For FACS, this function will locate XFirmwareCtrl in FADT first, and then
  24   FirmwareCtrl in FADT.
  25
  26   If PreviousTable is not NULL:
  27   1. If it could be located in XSDT in gEfiAcpi20TableGuid system configuration
  28      table, then this function will just locate next table in XSDT in
  29      gEfiAcpi20TableGuid system configuration table.
  30   2. If it could be located in RSDT in gEfiAcpi20TableGuid system configuration
  31      table, then this function will just locate next table in RSDT in
  32      gEfiAcpi20TableGuid system configuration table.
  33   3. If it could be located in RSDT in gEfiAcpi10TableGuid system configuration
  34      table, then this function will just locate next table in RSDT in
  35      gEfiAcpi10TableGuid system configuration table.
  36
  37   It's not supported that PreviousTable is not NULL but PreviousTable->Signature
  38   is not same with Signature, NULL will be returned.
  39
  40   @param Signature          ACPI table signature.
  41   @param PreviousTable      Pointer to previous returned table to locate next
  42                             table, or NULL to locate first table.
  43
  44   @return Next ACPI table or NULL if not found.
  45
  46 **/
  47 EFI_ACPI_COMMON_HEADER *
  48 EFIAPI
  49 EfiLocateNextAcpiTable (
  50   IN UINT32                     Signature,
  51   IN EFI_ACPI_COMMON_HEADER     *PreviousTable OPTIONAL
  52   )
  53 {
  54   ASSERT (FALSE);
  55   return NULL;
  56 }
  57
  58 /**
  59   This function locates first ACPI table in XSDT/RSDT based on Signature.
  60
  61   This function will locate the first ACPI table in XSDT/RSDT based on
  62   Signature in gEfiAcpi20TableGuid system configuration table first, and then
  63   gEfiAcpi10TableGuid system configuration table.
  64   This function will locate in XSDT first, and then RSDT.
  65   For DSDT, this function will locate XDsdt in FADT first, and then Dsdt in
  66   FADT.
  67   For FACS, this function will locate XFirmwareCtrl in FADT first, and then
  68   FirmwareCtrl in FADT.
  69
  70   @param Signature          ACPI table signature.
  71
  72   @return First ACPI table or NULL if not found.
  73
  74 **/
  75 EFI_ACPI_COMMON_HEADER *
  76 EFIAPI
  77 EfiLocateFirstAcpiTable (
  78   IN UINT32                     Signature
  79   )
  80 {
  81   return EfiLocateNextAcpiTable (Signature, NULL);
  82 }