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      1 /** @file
      2 Module produce EFI_PEI_READ_ONLY_VARIABLE2_PPI on top of EFI_PEI_READ_ONLY_VARIABLE_PPI.
      3 UEFI PI Spec supersedes Intel's Framework Specs.
      4 EFI_PEI_READ_ONLY_VARIABLE_PPI defined in Intel Framework Pkg is replaced by EFI_PEI_READ_ONLY_VARIABLE2_PPI
      5 in MdePkg.
      6 This module produces EFI_PEI_READ_ONLY_VARIABLE2_PPI on top of EFI_PEI_READ_ONLY_VARIABLE_PPI.
      7 This module is used on platform when both of these two conditions are true:
      8 1) Framework module produces EFI_PEI_READ_ONLY_VARIABLE_PPI is present.
      9 2) The platform has PI modules that only consumes EFI_PEI_READ_ONLY_VARIABLE2_PPI.
     10 
     11 This module can't be used together with ReadOnlyVariableToReadOnlyVariable2Thunk module.
     12 
     13 
     14 Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
     15 This program and the accompanying materials
     16 are licensed and made available under the terms and conditions of the BSD License
     17 which accompanies this distribution.  The full text of the license may be found at
     18 http://opensource.org/licenses/bsd-license.php
     19 
     20 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
     21 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
     22 Module Name:
     23 
     24 **/
     25 
     26 #include <PiPei.h>
     27 #include <Ppi/ReadOnlyVariable2.h>
     28 #include <Ppi/ReadOnlyVariable.h>
     29 #include <Library/DebugLib.h>
     30 #include <Library/PeiServicesTablePointerLib.h>
     31 #include <Library/PeiServicesLib.h>
     32 
     33 /**
     34   Provide the read variable functionality of the variable services.
     35 
     36   @param  This                  A pointer to this instance of the EFI_PEI_READ_ONLY_VARIABLE2_PPI.
     37   @param  VariableName          A pointer to a null-terminated string that is the variable's name.
     38   @param  VariableGuid          A pointer to an EFI_GUID that is the variable's GUID. The combination of
     39                                 VariableGuid and VariableName must be unique.
     40   @param  Attributes            If non-NULL, on return, points to the variable's attributes.
     41   @param  DataSize              On entry, points to the size in bytes of the Data buffer.
     42                                 On return, points to the size of the data returned in Data.
     43   @param  Data                  Points to the buffer which will hold the returned variable value.
     44 
     45   @retval EFI_SUCCESS           The interface could be successfully installed
     46   @retval EFI_NOT_FOUND         The variable could not be discovered
     47   @retval EFI_BUFFER_TOO_SMALL  The caller buffer is not large enough
     48 
     49 **/
     50 EFI_STATUS
     51 EFIAPI
     52 PeiGetVariable (
     53   IN CONST  EFI_PEI_READ_ONLY_VARIABLE2_PPI *This,
     54   IN CONST  CHAR16                          *VariableName,
     55   IN CONST  EFI_GUID                        *VariableGuid,
     56   OUT       UINT32                          *Attributes,
     57   IN OUT    UINTN                           *DataSize,
     58   OUT       VOID                            *Data
     59   )
     60 {
     61   EFI_STATUS                     Status;
     62   EFI_PEI_READ_ONLY_VARIABLE_PPI *ReadOnlyVariable;
     63 
     64   Status = PeiServicesLocatePpi (
     65              &gEfiPeiReadOnlyVariablePpiGuid,
     66              0,
     67              NULL,
     68              (VOID **)&ReadOnlyVariable
     69              );
     70   ASSERT_EFI_ERROR (Status);
     71 
     72   return ReadOnlyVariable->PeiGetVariable (
     73                              (EFI_PEI_SERVICES **) GetPeiServicesTablePointer (),
     74                              (CHAR16 *)VariableName,
     75                              (EFI_GUID *)VariableGuid,
     76                              Attributes,
     77                              DataSize,
     78                              Data
     79                              );
     80 }
     81 
     82 /**
     83   Provide the get next variable functionality of the variable services.
     84 
     85   @param  This              A pointer to this instance of the EFI_PEI_READ_ONLY_VARIABLE2_PPI.
     86 
     87   @param  VariableNameSize  On entry, points to the size of the buffer pointed to by VariableName.
     88   @param  VariableName      On entry, a pointer to a null-terminated string that is the variable's name.
     89                             On return, points to the next variable's null-terminated name string.
     90 
     91   @param  VariableGuid      On entry, a pointer to an EFI_GUID that is the variable's GUID.
     92                             On return, a pointer to the next variable's GUID.
     93 
     94   @retval EFI_SUCCESS       The interface could be successfully installed
     95   @retval EFI_NOT_FOUND     The variable could not be discovered
     96 
     97 **/
     98 EFI_STATUS
     99 EFIAPI
    100 PeiGetNextVariableName (
    101   IN CONST  EFI_PEI_READ_ONLY_VARIABLE2_PPI *This,
    102   IN OUT UINTN                              *VariableNameSize,
    103   IN OUT CHAR16                             *VariableName,
    104   IN OUT EFI_GUID                           *VariableGuid
    105   )
    106 {
    107   EFI_STATUS                     Status;
    108   EFI_PEI_READ_ONLY_VARIABLE_PPI *ReadOnlyVariable;
    109 
    110   Status = PeiServicesLocatePpi (
    111              &gEfiPeiReadOnlyVariablePpiGuid,
    112              0,
    113              NULL,
    114              (VOID **)&ReadOnlyVariable
    115              );
    116   ASSERT_EFI_ERROR (Status);
    117 
    118   return ReadOnlyVariable->PeiGetNextVariableName (
    119                              (EFI_PEI_SERVICES **) GetPeiServicesTablePointer (),
    120                              VariableNameSize,
    121                              VariableName,
    122                              VariableGuid
    123                              );
    124 }
    125 
    126 //
    127 // Module globals
    128 //
    129 EFI_PEI_READ_ONLY_VARIABLE2_PPI mVariablePpi = {
    130   PeiGetVariable,
    131   PeiGetNextVariableName
    132 };
    133 
    134 EFI_PEI_PPI_DESCRIPTOR     mPpiListVariable = {
    135   (EFI_PEI_PPI_DESCRIPTOR_PPI | EFI_PEI_PPI_DESCRIPTOR_TERMINATE_LIST),
    136   &gEfiPeiReadOnlyVariable2PpiGuid,
    137   &mVariablePpi
    138 };
    139 
    140 /**
    141   User entry for this PEIM driver.
    142 
    143   @param  FileHandle  Handle of the file being invoked.
    144   @param  PeiServices Describes the list of possible PEI Services.
    145 
    146   @retval EFI_SUCCESS ReadOnlyVariable2 PPI is successfully installed.
    147   @return Others      ReadOnlyVariable2 PPI is not successfully installed.
    148 
    149 **/
    150 EFI_STATUS
    151 EFIAPI
    152 PeimInitializeReadOnlyVariable2 (
    153   IN EFI_PEI_FILE_HANDLE       FileHandle,
    154   IN CONST EFI_PEI_SERVICES    **PeiServices
    155   )
    156 {
    157   //
    158   // This thunk module can only be used together with a PI PEI core, as we
    159   // assume PeiServices Pointer Table can be located in a standard way defined
    160   // in PI spec.
    161   //
    162   ASSERT ((*PeiServices)->Hdr.Revision >= 0x00010000);
    163 
    164   //
    165   // Developer should make sure ReadOnlyVariable2ToReadOnlyVariable module is not present. or else, the call chain will form a
    166   // infinite loop: ReadOnlyVariable2 -> ReadOnlyVariable -> ReadOnlyVariable2 -> .....
    167   //
    168   //
    169   // Publish the variable capability to other modules
    170   //
    171   return PeiServicesInstallPpi (&mPpiListVariable);
    172 }
    173