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/*++

Copyright (c) 1998  Intel Corporation

Module Name:

Abstract:

Revision History

--*/

//

// The variable store protocol interface is specific to the reference

// implementation.  The initialization code adds variable store devices

// to the system, and the FW connects to the devices to provide the

// variable store interfaces through these devices.

//

//

// Variable Store Device protocol

//

#define VARIABLE_STORE_PROTOCOL    \

    { 0xf088cd91, 0xa046, 0x11d2, {0x8e, 0x42, 0x0, 0xa0, 0xc9, 0x69, 0x72, 0x3b} }

INTERFACE_DECL(_EFI_VARIABLE_STORE);

typedef

EFI_STATUS

(EFIAPI *EFI_STORE_CLEAR) (

    IN struct _EFI_VARIABLE_STORE   *This,

    IN UINTN                        BankNo,

    IN OUT VOID                     *Scratch

    );

typedef

EFI_STATUS

(EFIAPI *EFI_STORE_READ) (

    IN struct _EFI_VARIABLE_STORE   *This,

    IN UINTN                        BankNo,

    IN UINTN                        Offset,

    IN UINTN                        BufferSize,

    OUT VOID                        *Buffer

    );

typedef

EFI_STATUS

(EFIAPI *EFI_STORE_UPDATE) (

    IN struct _EFI_VARIABLE_STORE   *This,

    IN UINTN                        BankNo,

    IN UINTN                        Offset,

    IN UINTN                        BufferSize,

    IN VOID                         *Buffer

    );

typedef

EFI_STATUS

(EFIAPI *EFI_STORE_SIZE) (

    IN struct _EFI_VARIABLE_STORE   *This,

    IN UINTN                        NoBanks

    );

typedef

EFI_STATUS

(EFIAPI *EFI_TRANSACTION_UPDATE) (

    IN struct _EFI_VARIABLE_STORE   *This,

    IN UINTN                        BankNo,

    IN VOID                         *NewContents

    );

typedef struct _EFI_VARIABLE_STORE {

    //

    // Number of banks and bank size

    //

    UINT32                      Attributes;

    UINT32                      BankSize;

    UINT32                      NoBanks;

    //

    // Functions to access the storage banks

    //

    EFI_STORE_CLEAR             ClearStore;

    EFI_STORE_READ              ReadStore;

    EFI_STORE_UPDATE            UpdateStore;

    EFI_STORE_SIZE              SizeStore OPTIONAL;

    EFI_TRANSACTION_UPDATE      TransactionUpdate OPTIONAL;

} EFI_VARIABLE_STORE;

//

//

// ClearStore()     - A function to clear the requested storage bank.  A cleared

//      bank contains all "on" bits.

//

// ReadStore()      - Read data from the requested store.

//

// UpdateStore()    - Updates data on the requested store. The FW will only

//      ever issue updates to clear bits in the store. Updates must be

//      performed in LSb to MSb order of the update buffer.

//

// SizeStore()      - An optional function for non-runtime stores that can be

//      dynamically sized.  The FW will only ever increase or decrease the store

//      by 1 banksize at a time, and it is always adding or removing a bank from 

//      the end of the store.

//

// By default the FW will update variables and storage banks in an

// "atomic" manner by keeping 1 old copy of the data during an update,

// and recovering appropiately if the power is lost during the middle

// of an operation.  To do this the FW needs to have multiple banks

// of storage dedicated to its use. If that's not possible, the driver 

// can implement an atomic bank update function and the FW will allow 

// 1 bank in this case.  (It will allow any number of banks,

// but it won't require an "extra" bank to provide its bank transaction 

// function).

//

// TransactionUpdate()  - An optional function that can clear & update an 

//      entire bank in an "atomic" fashion.  If the operation fails in the 

//      middle the driver is responsible for having either the previous copy 

//      of the bank's data or the new copy.  A copy that's partially written

//      is not valid as internal data settings may get lost.  Supply this

//      function only when needed.

//