IntelFrameworkPkg/Include/Ppi/ReadOnlyVariable.h File Reference


Data Structures

struct  _EFI_PEI_READ_ONLY_VARIABLE_PPI

Defines

#define EFI_PEI_READ_ONLY_VARIABLE_ACCESS_PPI_GUID
#define EFI_VARIABLE_NON_VOLATILE   0x00000001
#define EFI_VARIABLE_BOOTSERVICE_ACCESS   0x00000002
#define EFI_VARIABLE_RUNTIME_ACCESS   0x00000004
#define EFI_VARIABLE_READ_ONLY   0x00000008

Typedefs

typedef struct
_EFI_PEI_READ_ONLY_VARIABLE_PPI 
EFI_PEI_READ_ONLY_VARIABLE_PPI
typedef EFI_STATUS(EFIAPI * EFI_PEI_GET_VARIABLE )(IN EFI_PEI_SERVICES **PeiServices, IN CHAR16 *VariableName, IN EFI_GUID *VendorGuid, OUT UINT32 *Attributes, IN OUT UINTN *DataSize, OUT VOID *Data)
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)

Variables

EFI_GUID gEfiPeiReadOnlyVariablePpiGuid

Detailed Description

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 - 2010, Intel Corporation. All rights reserved.
This program and the accompanying materials are licensed and made available under the terms and conditions of the BSD License that 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.

Revision Reference:
This PPI is defined in PEI CIS Version 0.91.

Define Documentation

#define EFI_PEI_READ_ONLY_VARIABLE_ACCESS_PPI_GUID

Value:

{ \
    0x3cdc90c6, 0x13fb, 0x4a75, {0x9e, 0x79, 0x59, 0xe9, 0xdd, 0x78, 0xb9, 0xfa } \
  }

#define EFI_VARIABLE_BOOTSERVICE_ACCESS   0x00000002

Variable attributes.

#define EFI_VARIABLE_NON_VOLATILE   0x00000001

Variable attributes.

#define EFI_VARIABLE_READ_ONLY   0x00000008

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_RUNTIME_ACCESS   0x00000004

Variable attributes.


Typedef Documentation

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 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.

Parameters:
[in] PeiServices An indirect pointer to the PEI Services Table published by the PEI Foundation.
[in] VariableNameSize The size of the VariableName buffer.
[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.
[in] VendorGuid On input, supplies the last VendorGuid that was returned by GetNextVariableName(). On output, returns the VendorGuid of the current variable.
Return values:
EFI_SUCCESS The function completed successfully.
EFI_NOT_FOUND The next variable was not found.
EFI_BUFFER_TOO_SMALL The VariableNameSize is too small for the result.
EFI_INVALID_PARAMETER One of the parameters has an invalid value.
EFI_DEVICE_ERROR The variable name 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, IN OUT UINTN *DataSize, OUT VOID *Data)

Get Variable value by Name and GUID pair.

Parameters:
[in] PeiServices An indirect pointer to the PEI Services Table published by the PEI Foundation.
[in] VariableName A NULL-terminated Unicode string that is the name of the vendor's variable.
[in] VendorGuid A unique identifier for the vendor.
[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.
[in,out] DataSize On input, the size in bytes of the return Data buffer. On output, the size of data returned in Data.
[out] Data The buffer to return the contents of the variable.
Return values:
EFI_SUCCESS The function completed successfully.
EFI_NOT_FOUND The variable was not found.
EFI_BUFFER_TOO_SMALL The BufferSize is too small for the result.
EFI_INVALID_PARAMETER One of the parameters has an invalid value.
EFI_DEVICE_ERROR The variable could not be retrieved due to a hardware error.


Variable Documentation


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