efi64/include/efi/protocol/efivar.h

   1 /*++
   2
   3 Copyright (c) 1998  Intel Corporation
   4
   5 Module Name:
   6
   7 Abstract:
   8
   9
  10
  11 Revision History
  12
  13 --*/
  14
  15
  16
  17 //
  18 // The variable store protocol interface is specific to the reference
  19 // implementation.  The initialization code adds variable store devices
  20 // to the system, and the FW connects to the devices to provide the
  21 // variable store interfaces through these devices.
  22 //
  23
  24 //
  25 // Variable Store Device protocol
  26 //
  27
  28 #define VARIABLE_STORE_PROTOCOL    \
  29     { 0xf088cd91, 0xa046, 0x11d2, {0x8e, 0x42, 0x0, 0xa0, 0xc9, 0x69, 0x72, 0x3b} }
  30
  31 INTERFACE_DECL(_EFI_VARIABLE_STORE);
  32
  33 typedef
  34 EFI_STATUS
  35 (EFIAPI *EFI_STORE_CLEAR) (
  36     IN struct _EFI_VARIABLE_STORE   *This,
  37     IN UINTN                        BankNo,
  38     IN OUT VOID                     *Scratch
  39     );
  40
  41
  42 typedef
  43 EFI_STATUS
  44 (EFIAPI *EFI_STORE_READ) (
  45     IN struct _EFI_VARIABLE_STORE   *This,
  46     IN UINTN                        BankNo,
  47     IN UINTN                        Offset,
  48     IN UINTN                        BufferSize,
  49     OUT VOID                        *Buffer
  50     );
  51
  52 typedef
  53 EFI_STATUS
  54 (EFIAPI *EFI_STORE_UPDATE) (
  55     IN struct _EFI_VARIABLE_STORE   *This,
  56     IN UINTN                        BankNo,
  57     IN UINTN                        Offset,
  58     IN UINTN                        BufferSize,
  59     IN VOID                         *Buffer
  60     );
  61
  62 typedef
  63 EFI_STATUS
  64 (EFIAPI *EFI_STORE_SIZE) (
  65     IN struct _EFI_VARIABLE_STORE   *This,
  66     IN UINTN                        NoBanks
  67     );
  68
  69 typedef
  70 EFI_STATUS
  71 (EFIAPI *EFI_TRANSACTION_UPDATE) (
  72     IN struct _EFI_VARIABLE_STORE   *This,
  73     IN UINTN                        BankNo,
  74     IN VOID                         *NewContents
  75     );
  76
  77 typedef struct _EFI_VARIABLE_STORE {
  78
  79     //
  80     // Number of banks and bank size
  81     //
  82
  83     UINT32                      Attributes;
  84     UINT32                      BankSize;
  85     UINT32                      NoBanks;
  86
  87     //
  88     // Functions to access the storage banks
  89     //
  90
  91     EFI_STORE_CLEAR             ClearStore;
  92     EFI_STORE_READ              ReadStore;
  93     EFI_STORE_UPDATE            UpdateStore;
  94     EFI_STORE_SIZE              SizeStore OPTIONAL;
  95     EFI_TRANSACTION_UPDATE      TransactionUpdate OPTIONAL;
  96
  97 } EFI_VARIABLE_STORE;
  98
  99
 100 //
 101 //
 102 // ClearStore()     - A function to clear the requested storage bank.  A cleared
 103 //      bank contains all "on" bits.
 104 //
 105 // ReadStore()      - Read data from the requested store.
 106 //
 107 // UpdateStore()    - Updates data on the requested store. The FW will only
 108 //      ever issue updates to clear bits in the store. Updates must be
 109 //      performed in LSb to MSb order of the update buffer.
 110 //
 111 // SizeStore()      - An optional function for non-runtime stores that can be
 112 //      dynamically sized.  The FW will only ever increase or decrease the store
 113 //      by 1 banksize at a time, and it is always adding or removing a bank from
 114 //      the end of the store.
 115 //
 116 // By default the FW will update variables and storage banks in an
 117 // "atomic" manner by keeping 1 old copy of the data during an update,
 118 // and recovering appropiately if the power is lost during the middle
 119 // of an operation.  To do this the FW needs to have multiple banks
 120 // of storage dedicated to its use. If that's not possible, the driver
 121 // can implement an atomic bank update function and the FW will allow
 122 // 1 bank in this case.  (It will allow any number of banks,
 123 // but it won't require an "extra" bank to provide its bank transaction
 124 // function).
 125 //
 126 // TransactionUpdate()  - An optional function that can clear & update an
 127 //      entire bank in an "atomic" fashion.  If the operation fails in the
 128 //      middle the driver is responsible for having either the previous copy
 129 //      of the bank's data or the new copy.  A copy that's partially written
 130 //      is not valid as internal data settings may get lost.  Supply this
 131 //      function only when needed.
 132 //
 133