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- /** @file
- This file declares the Read-only Variable Service PPI, which is required by the framework spec.
- These services provide a lightweight, read-only variant of the full EFI variable services. The
- reason that these services are read-only is to reduce the complexity of flash management. Also,
- some implementation of the PEI may use the same physical flash part for variable and PEIM
- storage. As such, a write command to certain technologies would alter the contents of the entire part,
- making the PEIM execution in the original position not follow the required flow.
- Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
- SPDX-License-Identifier: BSD-2-Clause-Patent
- @par Revision Reference:
- This PPI is defined in PEI CIS
- Version 0.91.
- **/
- #ifndef __PEI_READ_ONLY_VARIABLE_PPI_H__
- #define __PEI_READ_ONLY_VARIABLE_PPI_H__
- #define EFI_PEI_READ_ONLY_VARIABLE_ACCESS_PPI_GUID \
- { \
- 0x3cdc90c6, 0x13fb, 0x4a75, {0x9e, 0x79, 0x59, 0xe9, 0xdd, 0x78, 0xb9, 0xfa } \
- }
- typedef struct _EFI_PEI_READ_ONLY_VARIABLE_PPI EFI_PEI_READ_ONLY_VARIABLE_PPI;
- ///
- /// Variable attributes.
- ///@{
- #define EFI_VARIABLE_NON_VOLATILE 0x00000001
- #define EFI_VARIABLE_BOOTSERVICE_ACCESS 0x00000002
- #define EFI_VARIABLE_RUNTIME_ACCESS 0x00000004
- ///
- /// Inconsistent with specification here:
- /// In Framework Spec, PeiCis0.91, neither the macro or its value is defined.
- /// Keeping this inconsistancy for backward compatibility.
- ///
- #define EFI_VARIABLE_READ_ONLY 0x00000008
- ///@}
- /**
- Get Variable value by Name and GUID pair.
- @param[in] PeiServices An indirect pointer to the PEI Services Table published
- by the PEI Foundation.
- @param[in] VariableName A NULL-terminated Unicode string that is the name of the vendor's variable.
- @param[in] VendorGuid A unique identifier for the vendor.
- @param[out] Attributes This OPTIONAL parameter may be either NULL or
- a pointer to the location in which to return
- the attributes bitmask for the variable.
- @param[in,out] DataSize On input, the size in bytes of the return Data buffer.
- On output, the size of data returned in Data.
- @param[out] Data The buffer to return the contents of the variable.
- @retval EFI_SUCCESS The function completed successfully.
- @retval EFI_NOT_FOUND The variable was not found.
- @retval EFI_BUFFER_TOO_SMALL The BufferSize is too small for the result.
- @retval EFI_INVALID_PARAMETER One of the parameters has an invalid value.
- @retval EFI_DEVICE_ERROR The variable could not be retrieved due to a hardware error.
- **/
- typedef
- EFI_STATUS
- (EFIAPI *EFI_PEI_GET_VARIABLE)(
- IN EFI_PEI_SERVICES **PeiServices,
- IN CHAR16 *VariableName,
- IN EFI_GUID *VendorGuid,
- OUT UINT32 *Attributes OPTIONAL,
- IN OUT UINTN *DataSize,
- OUT VOID *Data
- );
- /**
- This function can be called multiple times to retrieve the VariableName
- and VendorGuid of all variables currently available in the system. On each call
- to GetNextVariableName(), the previous results are passed into the interface,
- and on output the interface returns the next variable name data. When the
- entire variable list has been returned, the error EFI_NOT_FOUND is returned.
- @param[in] PeiServices An indirect pointer to the PEI Services Table
- published by the PEI Foundation.
- @param[in] VariableNameSize The size of the VariableName buffer.
- @param[in] VariableName On input, supplies the last VariableName that was
- returned by GetNextVariableName(). On output,
- returns the Null-terminated Unicode string of the
- current variable.
- @param[in] VendorGuid On input, supplies the last VendorGuid that was
- returned by GetNextVariableName(). On output,
- returns the VendorGuid of the current variable.
- @retval EFI_SUCCESS The function completed successfully.
- @retval EFI_NOT_FOUND The next variable was not found.
- @retval EFI_BUFFER_TOO_SMALL The VariableNameSize is too small for the result.
- @retval EFI_INVALID_PARAMETER One of the parameters has an invalid value.
- @retval EFI_DEVICE_ERROR The variable name could not be retrieved due to
- a hardware error.
- **/
- typedef
- EFI_STATUS
- (EFIAPI *EFI_PEI_GET_NEXT_VARIABLE_NAME)(
- IN EFI_PEI_SERVICES **PeiServices,
- IN OUT UINTN *VariableNameSize,
- IN OUT CHAR16 *VariableName,
- IN OUT EFI_GUID *VendorGuid
- );
- ///
- /// This PPI provides a lightweight, read-only variant of the full EFI
- /// variable services.
- ///
- struct _EFI_PEI_READ_ONLY_VARIABLE_PPI {
- ///
- /// Inconsistent with specification here:
- /// In Framework Spec, PeiCis0.91, the field is named as GetVariable and GetNextVariableName.
- /// Keeping this inconsistancy for backward compatibility.
- ///
- EFI_PEI_GET_VARIABLE PeiGetVariable; ///< A service to ascertain a given variable name.
- EFI_PEI_GET_NEXT_VARIABLE_NAME PeiGetNextVariableName; ///< A service to ascertain a variable based upon a given, known variable
- };
- extern EFI_GUID gEfiPeiReadOnlyVariablePpiGuid;
- #endif /* __PEI_READ_ONLY_VARIABLE_PPI_H__ */
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