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/** @file
This file declares the Variable Storage PPI
This PPI abstracts read-only access to the UEFI variable store on a
NVM (Non-Volatile Memory) device during the PEI phase.
Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php.
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#ifndef _PEI_VARIABLE_STORAGE_PPI_H_
#define _PEI_VARIABLE_STORAGE_PPI_H_
extern EFI_GUID gVariableStoragePpiGuid;
///
/// Revision
///
#define PEI_VARIABLE_STORAGE_PPI_REVISION 1
typedef struct _VARIABLE_STORAGE_PPI VARIABLE_STORAGE_PPI;
/**
Retrieves a PPI instance-specific GUID.
Returns a unique GUID per VARIABLE_STORAGE_PPI instance.
@param[out] VariableGuid A pointer to an EFI_GUID that is this PPI instance's GUID.
@retval EFI_SUCCESS The data was returned successfully.
@retval EFI_INVALID_PARAMETER A required parameter is NULL.
**/
typedef
EFI_STATUS
(EFIAPI *PEI_VARIABLE_STORAGE_GET_ID)(
OUT EFI_GUID *InstanceGuid
);
/**
This service retrieves a variable's value using its name and GUID.
Read the specified variable from the UEFI variable store. If the Data
buffer is too small to hold the contents of the variable,
the error EFI_BUFFER_TOO_SMALL is returned and DataSize is set to the
required buffer size to obtain the data.
@param[in] This A pointer to this instance of the VARIABLE_STORAGE_PPI.
@param[in] VariableName A pointer to a null-terminated string that is the variable's name.
@param[in] VariableGuid A pointer to an EFI_GUID that is the variable's GUID. The combination of
VariableGuid and VariableName must be unique.
@param[out] Attributes If non-NULL, on return, points to the variable's attributes.
@param[in, out] DataSize On entry, points to the size in bytes of the Data buffer.
On return, points to the size of the data returned in Data.
@param[out] Data Points to the buffer which will hold the returned variable value.
@retval EFI_SUCCESS The variable was read successfully.
@retval EFI_NOT_FOUND The variable could not be found.
@retval EFI_BUFFER_TOO_SMALL The DataSize is too small for the resulting data.
DataSize is updated with the size required for
the specified variable.
@retval EFI_INVALID_PARAMETER VariableName, VariableGuid, DataSize or Data is NULL.
@retval EFI_DEVICE_ERROR The variable could not be retrieved because of a device error.
**/
typedef
EFI_STATUS
(EFIAPI *PEI_VARIABLE_STORAGE_GET_VARIABLE)(
IN CONST VARIABLE_STORAGE_PPI *This,
IN CONST CHAR16 *VariableName,
IN CONST EFI_GUID *VariableGuid,
OUT UINT32 *Attributes,
IN OUT UINTN *DataSize,
OUT VOID *Data
);
/**
Return the next variable name and GUID.
This function is called multiple times to retrieve the VariableName
and VariableGuid of all variables currently available in the system.
On each call, the previous results are passed into the interface,
and, on return, the interface returns the data for the next
interface. When the entire variable list has been returned,
EFI_NOT_FOUND is returned.
@param[in] This A pointer to this instance of the VARIABLE_STORAGE_PPI.
@param[in, out] VariableNameSize On entry, points to the size of the buffer pointed to by
VariableName. On return, the size of the variable name buffer.
@param[in, out] VariableName On entry, a pointer to a null-terminated string that is the
variable's name. On return, points to the next variable's
null-terminated name string.
@param[in, out] VariableGuid On entry, a pointer to an EFI_GUID that is the variable's GUID.
On return, a pointer to the next variable's GUID.
@param[out] VariableAttributes A pointer to the variable attributes.
@retval EFI_SUCCESS The variable was read successfully.
@retval EFI_NOT_FOUND The variable could not be found.
@retval EFI_BUFFER_TOO_SMALL The VariableNameSize is too small for the resulting
data. VariableNameSize is updated with the size
required for the specified variable.
@retval EFI_INVALID_PARAMETER VariableName, VariableGuid or
VariableNameSize is NULL.
@retval EFI_DEVICE_ERROR The variable could not be retrieved because of a device error.
**/
typedef
EFI_STATUS
(EFIAPI *PEI_VARIABLE_STORAGE_GET_NEXT_VARIABLE_NAME)(
IN CONST VARIABLE_STORAGE_PPI *This,
IN OUT UINTN *VariableNameSize,
IN OUT CHAR16 *VariableName,
IN OUT EFI_GUID *VariableGuid,
OUT UINT32 *VariableAttributes
);
///
/// Variable Storage PPI
/// Interface functions for variable NVM storage access in PEI phase.
///
struct _VARIABLE_STORAGE_PPI {
PEI_VARIABLE_STORAGE_GET_ID GetId; ///< Retrieves a PPI instance-specific GUID
PEI_VARIABLE_STORAGE_GET_VARIABLE GetVariable; ///< Retrieves a variable's value given its name and GUID
PEI_VARIABLE_STORAGE_GET_NEXT_VARIABLE_NAME GetNextVariableName; ///< Return the next variable name and GUID
};
#endif
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