MdePkg/Include/Ppi/ReadOnlyVariable.h

   1 /** @file
   2   This file declares Read-only Variable Service PPI
   3
   4   Copyright (c) 2006, Intel Corporation
   5   All rights reserved. This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13   Module Name:  ReadOnlyVariable.h
  14
  15   @par Revision Reference:
  16   This PPI is defined in PEI CIS
  17   Version 0.91.
  18
  19 **/
  20
  21 #ifndef __PEI_READ_ONLY_VARIABLE_PPI_H__
  22 #define __PEI_READ_ONLY_VARIABLE_PPI_H__
  23
  24 #define EFI_PEI_READ_ONLY_VARIABLE_ACCESS_PPI_GUID \
  25   { \
  26     0x3cdc90c6, 0x13fb, 0x4a75, {0x9e, 0x79, 0x59, 0xe9, 0xdd, 0x78, 0xb9, 0xfa } \
  27   }
  28
  29 typedef struct _EFI_PEI_READ_ONLY_VARIABLE_PPI  EFI_PEI_READ_ONLY_VARIABLE_PPI;
  30
  31 //
  32 // Variable attributes
  33 //
  34 #define EFI_VARIABLE_NON_VOLATILE       0x00000001
  35 #define EFI_VARIABLE_BOOTSERVICE_ACCESS 0x00000002
  36 #define EFI_VARIABLE_RUNTIME_ACCESS     0x00000004
  37 #define EFI_VARIABLE_READ_ONLY          0x00000008
  38
  39 /**
  40   Get Variable value by Name and GUID pair
  41
  42   @param  PeiServices An indirect pointer to the PEI Services Table published by the PEI Foundation.
  43
  44   @param  VariableName A NULL-terminated Unicode string that is the name of the vendor¡¯s variable.
  45
  46   @param  VendorGuid A unique identifier for the vendor.
  47
  48   @param  Attributes If not NULL, a pointer to the memory location to return
  49   the attributes bitmask for the variable.
  50
  51   @param  DataSize On input, the size in bytes of the return Data buffer.
  52   On output, the size of data returned in Data.
  53
  54   @param  Data The buffer to return the contents of the variable.
  55
  56   @retval EFI_SUCCESS The function completed successfully.
  57
  58   @retval EFI_NOT_FOUND The variable was not found.
  59
  60   @retval EFI_BUFFER_TOO_SMALL The BufferSize is too small for the result.
  61
  62   @retval EFI_INVALID_PARAMETER One of the parameters has an invalid value.
  63
  64   @retval EFI_DEVICE_ERROR The variable could not be retrieved due to a hardware error.
  65
  66 **/
  67 typedef
  68 EFI_STATUS
  69 (EFIAPI *EFI_PEI_GET_VARIABLE) (
  70   IN EFI_PEI_SERVICES             **PeiServices,
  71   IN CHAR16                       *VariableName,
  72   IN EFI_GUID                     *VendorGuid,
  73   OUT UINT32                      *Attributes OPTIONAL,
  74   IN OUT UINTN                    *DataSize,
  75   OUT VOID                        *Data
  76   );
  77
  78 /**
  79   This function can be called multiple times to retrieve the VariableName
  80   and VendorGuid of all variables currently available in the system. On each call
  81   to GetNextVariableName() the previous results are passed into the interface,
  82   and on output the interface returns the next variable name data.  When the
  83   entire variable list has been returned, the error EFI_NOT_FOUND is returned.
  84
  85   @param  PeiServices An indirect pointer to the PEI Services Table published by the PEI Foundation.
  86
  87   @param  VariableNameSize The size of the VariableName buffer.
  88
  89   @param  VariableName On input, supplies the last VariableName that was
  90   returned by GetNextVariableName().  On output, returns the Null-terminated
  91   Unicode string of the current variable.
  92
  93   @param  VendorGuid On input, supplies the last VendorGuid that was
  94   returned by GetNextVariableName().  On output, returns the VendorGuid
  95   of the current variable.
  96
  97   @retval EFI_SUCCESS The function completed successfully.
  98
  99   @retval EFI_NOT_FOUND The next variable was not found.
 100
 101   @retval EFI_BUFFER_TOO_SMALL The VariableNameSize is too small for the result.
 102
 103   @retval EFI_INVALID_PARAMETER One of the parameters has an invalid value.
 104
 105   @retval EFI_DEVICE_ERROR The variable name could not be retrieved due to a hardware error.
 106
 107 **/
 108 typedef
 109 EFI_STATUS
 110 (EFIAPI *EFI_PEI_GET_NEXT_VARIABLE_NAME) (
 111   IN EFI_PEI_SERVICES             **PeiServices,
 112   IN OUT UINTN                    *VariableNameSize,
 113   IN OUT CHAR16                   *VariableName,
 114   IN OUT EFI_GUID                 *VendorGuid
 115   );
 116
 117 /**
 118   @par Ppi Description:
 119   This PPI provides a lightweight, read-only variant of the full EFI
 120   variable services.
 121
 122   @param GetVariable
 123   A service to ascertain a given variable name.
 124
 125   @param GetNextVariableName
 126   A service to ascertain a variable based upon a given, known variable
 127
 128 **/
 129 struct _EFI_PEI_READ_ONLY_VARIABLE_PPI {
 130   EFI_PEI_GET_VARIABLE            PeiGetVariable;
 131   EFI_PEI_GET_NEXT_VARIABLE_NAME  PeiGetNextVariableName;
 132 };
 133
 134 extern EFI_GUID gEfiPeiReadOnlyVariablePpiGuid;
 135
 136 #endif