DynamicTablesPkg/Library/Common/AcpiHelperLib/AcpiHelper.c

   1 /** @file
   2   Acpi Helper
   3
   4   Copyright (c) 2017 - 2021, Arm Limited. All rights reserved.<BR>
   5
   6   SPDX-License-Identifier: BSD-2-Clause-Patent
   7 **/
   8
   9 #include <Library/BaseLib.h>
  10 #include <Library/DebugLib.h>
  11
  12 // Module specific include files.
  13 #include <Library/AcpiHelperLib.h>
  14
  15 /** Convert a hex number to its ASCII code.
  16
  17  @param [in]  x   Hex number to convert.
  18                   Must be 0 <= x < 16.
  19
  20  @return The ASCII code corresponding to x.
  21 **/
  22 UINT8
  23 EFIAPI
  24 AsciiFromHex (
  25   IN  UINT8   x
  26   )
  27 {
  28   if (x < 10) {
  29     return (UINT8)(x + '0');
  30   }
  31
  32   if (x < 16) {
  33     return (UINT8)(x - 10 + 'A');
  34   }
  35
  36   ASSERT (FALSE);
  37   return (UINT8)-1;
  38 }
  39
  40 /** Check if a HID is a valid PNP ID.
  41
  42   @param     [in] Hid     The Hid to validate.
  43
  44   @retval    TRUE         The Hid is a valid PNP ID.
  45   @retval    FALSE        The Hid is not a valid PNP ID.
  46 **/
  47 BOOLEAN
  48 IsValidPnpId (
  49   IN  CONST CHAR8  * Hid
  50   )
  51 {
  52   UINTN Index;
  53
  54   if (AsciiStrLen (Hid) != 7) {
  55     return FALSE;
  56   }
  57
  58   // A valid PNP ID must be of the form "AAA####"
  59   // where A is an uppercase letter and # is a hex digit.
  60   for (Index = 0; Index < 3; Index++) {
  61     if (!IS_UPPER_CHAR (Hid[Index])) {
  62       return FALSE;
  63     }
  64   }
  65
  66   for (Index = 3; Index < 7; Index++) {
  67     if (!IS_UPPER_HEX (Hid[Index])) {
  68       return FALSE;
  69     }
  70   }
  71
  72   return TRUE;
  73 }
  74
  75 /** Check if a HID is a valid ACPI ID.
  76
  77   @param     [in] Hid     The Hid to validate.
  78
  79   @retval    TRUE         The Hid is a valid ACPI ID.
  80   @retval    FALSE        The Hid is not a valid ACPI ID.
  81 **/
  82 BOOLEAN
  83 IsValidAcpiId (
  84   IN  CONST CHAR8  * Hid
  85   )
  86 {
  87   UINTN Index;
  88
  89   if (AsciiStrLen (Hid) != 8) {
  90     return FALSE;
  91   }
  92
  93   // A valid ACPI ID must be of the form "NNNN####"
  94   // where N is an uppercase letter or a digit ('0'-'9')
  95   // and # is a hex digit.
  96   for (Index = 0; Index < 4; Index++) {
  97     if (!(IS_UPPER_CHAR (Hid[Index]) || IS_DIGIT (Hid[Index]))) {
  98       return FALSE;
  99     }
 100   }
 101
 102   for (Index = 4; Index < 8; Index++) {
 103     if (!IS_UPPER_HEX (Hid[Index])) {
 104       return FALSE;
 105     }
 106   }
 107
 108   return TRUE;
 109 }