DynamicTablesPkg/Library/Common/AmlLib/ResourceData/AmlResourceData.c

   1 /** @file
   2   AML Resource Data.
   3
   4   Copyright (c) 2019 - 2020, Arm Limited. All rights reserved.<BR>
   5
   6   SPDX-License-Identifier: BSD-2-Clause-Patent
   7
   8   @par Glossary:
   9   - Rd or RD   - Resource Data
  10   - Rds or RDS - Resource Data Small
  11   - Rdl or RDL - Resource Data Large
  12 **/
  13
  14 #include <ResourceData/AmlResourceData.h>
  15
  16 /** Check whether the resource data has the input descriptor Id.
  17
  18   The small/large bit is included in the descriptor Id,
  19   but the size bits are not included for small resource data elements.
  20
  21   @param  [in]  Header        Pointer to the first byte of a resource data
  22                               element.
  23   @param  [in]  DescriptorId  The descriptor to check against.
  24
  25   @retval TRUE    The resource data has the descriptor Id.
  26   @retval FALSE   Otherwise.
  27 **/
  28 BOOLEAN
  29 EFIAPI
  30 AmlRdCompareDescId (
  31   IN  CONST AML_RD_HEADER  *Header,
  32   IN        AML_RD_HEADER  DescriptorId
  33   )
  34 {
  35   if (Header == NULL) {
  36     ASSERT (0);
  37     return FALSE;
  38   }
  39
  40   if (AML_RD_IS_LARGE (Header)) {
  41     return ((*Header ^ DescriptorId) == 0);
  42   } else {
  43     return (((*Header & AML_RD_SMALL_ID_MASK) ^ DescriptorId) == 0);
  44   }
  45 }
  46
  47 /** Get the descriptor Id of the resource data.
  48
  49   The small/large bit is included in the descriptor Id,
  50   but the size bits are not included for small resource data elements.
  51
  52   @param  [in]  Header  Pointer to the first byte of a resource data.
  53
  54   @return A descriptor Id.
  55 **/
  56 AML_RD_HEADER
  57 EFIAPI
  58 AmlRdGetDescId (
  59   IN  CONST AML_RD_HEADER  *Header
  60   )
  61 {
  62   if (Header == NULL) {
  63     ASSERT (0);
  64     return FALSE;
  65   }
  66
  67   if (AML_RD_IS_LARGE (Header)) {
  68     return *Header;
  69   }
  70
  71   // Header is a small resource data element.
  72   return *Header & AML_RD_SMALL_ID_MASK;
  73 }
  74
  75 /** Get the size of a resource data element.
  76
  77   If the resource data element is of the large type, the Header
  78   is expected to be at least 3 bytes long.
  79
  80   @param  [in]  Header  Pointer to the first byte of a resource data.
  81
  82   @return The size of the resource data element.
  83 **/
  84 UINT32
  85 EFIAPI
  86 AmlRdGetSize (
  87   IN  CONST AML_RD_HEADER  *Header
  88   )
  89 {
  90   if (Header == NULL) {
  91     ASSERT (0);
  92     return FALSE;
  93   }
  94
  95   if (AML_RD_IS_LARGE (Header)) {
  96     return ((ACPI_LARGE_RESOURCE_HEADER *)Header)->Length +
  97            sizeof (ACPI_LARGE_RESOURCE_HEADER);
  98   }
  99
 100   // Header is a small resource data element.
 101   return ((ACPI_SMALL_RESOURCE_HEADER *)Header)->Bits.Length +
 102          sizeof (ACPI_SMALL_RESOURCE_HEADER);
 103 }
 104
 105 /** Set the Checksum of an EndTag resource data.
 106
 107   ACPI 6.4, s6.4.2.9 "End Tag":
 108   "This checksum is generated such that adding it to the sum of all the data
 109   bytes will produce a zero sum."
 110   "If the checksum field is zero, the resource data is treated as if the
 111   checksum operation succeeded. Configuration proceeds normally."
 112
 113   @param  [in]  Header     Pointer to the first byte of a resource data.
 114   @param  [in]  CheckSum   Checksum value to set.
 115
 116   @retval EFI_SUCCESS             The function completed successfully.
 117   @retval EFI_INVALID_PARAMETER   Invalid parameter.
 118 **/
 119 EFI_STATUS
 120 EFIAPI
 121 AmlRdSetEndTagChecksum (
 122   IN  CONST AML_RD_HEADER  *Header,
 123   IN        UINT8          CheckSum
 124   )
 125 {
 126   if ((Header == NULL)  ||
 127       !AmlRdCompareDescId (
 128          Header,
 129          AML_RD_BUILD_SMALL_DESC_ID (ACPI_SMALL_END_TAG_DESCRIPTOR_NAME)
 130          ))
 131   {
 132     ASSERT (0);
 133     return EFI_INVALID_PARAMETER;
 134   }
 135
 136   ((EFI_ACPI_END_TAG_DESCRIPTOR *)Header)->Checksum = CheckSum;
 137   return EFI_SUCCESS;
 138 }