MdeModulePkg/Universal/Variable/Pei/Variable.h

   1 /** @file
   2
   3   The internal header file includes the common header files, defines
   4   internal structure and functions used by PeiVariable module.
   5
   6 Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
   7 This program and the accompanying materials
   8 are licensed and made available under the terms and conditions of the BSD License
   9 which accompanies this distribution.  The full text of the license may be found at
  10 http://opensource.org/licenses/bsd-license.php
  11
  12 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  13 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  14
  15 **/
  16
  17 #ifndef _PEI_VARIABLE_H_
  18 #define _PEI_VARIABLE_H_
  19
  20 #include <PiPei.h>
  21 #include <Ppi/ReadOnlyVariable2.h>
  22
  23 #include <Library/DebugLib.h>
  24 #include <Library/PeimEntryPoint.h>
  25 #include <Library/HobLib.h>
  26 #include <Library/PcdLib.h>
  27 #include <Library/BaseMemoryLib.h>
  28 #include <Library/PeiServicesTablePointerLib.h>
  29 #include <Library/PeiServicesLib.h>
  30
  31 #include <Guid/VariableFormat.h>
  32
  33 typedef struct {
  34   VARIABLE_HEADER *CurrPtr;
  35   VARIABLE_HEADER *EndPtr;
  36   VARIABLE_HEADER *StartPtr;
  37 } VARIABLE_POINTER_TRACK;
  38
  39 #define VARIABLE_INDEX_TABLE_VOLUME 122
  40
  41 #define EFI_VARIABLE_INDEX_TABLE_GUID \
  42   { 0x8cfdb8c8, 0xd6b2, 0x40f3, { 0x8e, 0x97, 0x02, 0x30, 0x7c, 0xc9, 0x8b, 0x7c } }
  43
  44 ///
  45 /// Use this data structure to store variable-related info, which can decrease
  46 /// the cost of access to NV.
  47 ///
  48 typedef struct {
  49   UINT16          Length;
  50   UINT16          GoneThrough;
  51   VARIABLE_HEADER *EndPtr;
  52   VARIABLE_HEADER *StartPtr;
  53   ///
  54   /// This field is used to store the distance of two neighbouring VAR_ADDED type variables.
  55   /// The meaning of the field is implement-dependent.
  56   UINT16          Index[VARIABLE_INDEX_TABLE_VOLUME];
  57 } VARIABLE_INDEX_TABLE;
  58
  59
  60 //
  61 // Functions
  62 //
  63 /**
  64   Provide the functionality of the variable services.
  65
  66   @param  FileHandle  Handle of the file being invoked.
  67                       Type EFI_PEI_FILE_HANDLE is defined in FfsFindNextFile().
  68   @param  PeiServices  General purpose services available to every PEIM.
  69
  70   @retval EFI_SUCCESS  If the interface could be successfully installed
  71   @retval Others       Returned from PeiServicesInstallPpi()
  72
  73 **/
  74 EFI_STATUS
  75 EFIAPI
  76 PeimInitializeVariableServices (
  77   IN       EFI_PEI_FILE_HANDLE       FileHandle,
  78   IN CONST EFI_PEI_SERVICES          **PeiServices
  79   );
  80
  81 /**
  82   This service retrieves a variable's value using its name and GUID.
  83
  84   Read the specified variable from the UEFI variable store. If the Data
  85   buffer is too small to hold the contents of the variable, the error
  86   EFI_BUFFER_TOO_SMALL is returned and DataSize is set to the required buffer
  87   size to obtain the data.
  88
  89   @param  This                  A pointer to this instance of the EFI_PEI_READ_ONLY_VARIABLE2_PPI.
  90   @param  VariableName          A pointer to a null-terminated string that is the variable's name.
  91   @param  VariableGuid          A pointer to an EFI_GUID that is the variable's GUID. The combination of
  92                                 VariableGuid and VariableName must be unique.
  93   @param  Attributes            If non-NULL, on return, points to the variable's attributes.
  94   @param  DataSize              On entry, points to the size in bytes of the Data buffer.
  95                                 On return, points to the size of the data returned in Data.
  96   @param  Data                  Points to the buffer which will hold the returned variable value.
  97
  98   @retval EFI_SUCCESS           The variable was read successfully.
  99   @retval EFI_NOT_FOUND         The variable could not be found.
 100   @retval EFI_BUFFER_TOO_SMALL  The DataSize is too small for the resulting data.
 101                                 DataSize is updated with the size required for
 102                                 the specified variable.
 103   @retval EFI_INVALID_PARAMETER VariableName, VariableGuid, DataSize or Data is NULL.
 104   @retval EFI_DEVICE_ERROR      The variable could not be retrieved because of a device error.
 105
 106 **/
 107 EFI_STATUS
 108 EFIAPI
 109 PeiGetVariable (
 110   IN CONST  EFI_PEI_READ_ONLY_VARIABLE2_PPI *This,
 111   IN CONST  CHAR16                          *VariableName,
 112   IN CONST  EFI_GUID                        *VariableGuid,
 113   OUT       UINT32                          *Attributes,
 114   IN OUT    UINTN                           *DataSize,
 115   OUT       VOID                            *Data
 116   );
 117
 118 /**
 119   Return the next variable name and GUID.
 120
 121   This function is called multiple times to retrieve the VariableName
 122   and VariableGuid of all variables currently available in the system.
 123   On each call, the previous results are passed into the interface,
 124   and, on return, the interface returns the data for the next
 125   interface. When the entire variable list has been returned,
 126   EFI_NOT_FOUND is returned.
 127
 128   @param  This              A pointer to this instance of the EFI_PEI_READ_ONLY_VARIABLE2_PPI.
 129
 130   @param  VariableNameSize  On entry, points to the size of the buffer pointed to by VariableName.
 131   @param  VariableName      On entry, a pointer to a null-terminated string that is the variable's name.
 132                             On return, points to the next variable's null-terminated name string.
 133
 134   @param  VariableGuid      On entry, a pointer to an UEFI _GUID that is the variable's GUID.
 135                             On return, a pointer to the next variable's GUID.
 136
 137   @retval EFI_SUCCESS           The variable was read successfully.
 138   @retval EFI_NOT_FOUND         The variable could not be found.
 139   @retval EFI_BUFFER_TOO_SMALL  The VariableNameSize is too small for the resulting
 140                                 data. VariableNameSize is updated with the size
 141                                 required for the specified variable.
 142   @retval EFI_INVALID_PARAMETER VariableName, VariableGuid or
 143                                 VariableNameSize is NULL.
 144   @retval EFI_DEVICE_ERROR      The variable could not be retrieved because of a device error.
 145
 146 **/
 147 EFI_STATUS
 148 EFIAPI
 149 PeiGetNextVariableName (
 150   IN CONST  EFI_PEI_READ_ONLY_VARIABLE2_PPI *This,
 151   IN OUT UINTN                              *VariableNameSize,
 152   IN OUT CHAR16                             *VariableName,
 153   IN OUT EFI_GUID                           *VariableGuid
 154   );
 155
 156 #endif