MdePkg/Include/Protocol/SmmAccess2.h

   1 /** @file
   2   EFI SMM Access2 Protocol as defined in the PI 1.2 specification.
   3
   4   This protocol is used to control the visibility of the SMRAM on the platform.
   5   It abstracts the location and characteristics of SMRAM.  The expectation is
   6   that the north bridge or memory controller would publish this protocol.
   7
   8   The principal functionality found in the memory controller includes the following:
   9   - Exposing the SMRAM to all non-SMM agents, or the "open" state
  10   - Shrouding the SMRAM to all but the SMM agents, or the "closed" state
  11   - Preserving the system integrity, or "locking" the SMRAM, such that the settings cannot be
  12     perturbed by either boot service or runtime agents
  13
  14   Copyright (c) 2009 - 2010, Intel Corporation. All rights reserved.<BR>
  15   This program and the accompanying materials
  16   are licensed and made available under the terms and conditions of the BSD License
  17   which accompanies this distribution.  The full text of the license may be found at
  18   http://opensource.org/licenses/bsd-license.php
  19
  20   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  21   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  22
  23 **/
  24
  25 #ifndef _SMM_ACCESS2_H_
  26 #define _SMM_ACCESS2_H_
  27
  28 #define EFI_SMM_ACCESS2_PROTOCOL_GUID \
  29   { \
  30      0xc2702b74, 0x800c, 0x4131, {0x87, 0x46, 0x8f, 0xb5, 0xb8, 0x9c, 0xe4, 0xac } \
  31   }
  32
  33
  34 typedef struct _EFI_SMM_ACCESS2_PROTOCOL  EFI_SMM_ACCESS2_PROTOCOL;
  35
  36 /**
  37   Opens the SMRAM area to be accessible by a boot-service driver.
  38
  39   This function "opens" SMRAM so that it is visible while not inside of SMM. The function should
  40   return EFI_UNSUPPORTED if the hardware does not support hiding of SMRAM. The function
  41   should return EFI_DEVICE_ERROR if the SMRAM configuration is locked.
  42
  43   @param[in] This           The EFI_SMM_ACCESS2_PROTOCOL instance.
  44
  45   @retval EFI_SUCCESS       The operation was successful.
  46   @retval EFI_UNSUPPORTED   The system does not support opening and closing of SMRAM.
  47   @retval EFI_DEVICE_ERROR  SMRAM cannot be opened, perhaps because it is locked.
  48 **/
  49 typedef
  50 EFI_STATUS
  51 (EFIAPI *EFI_SMM_OPEN2)(
  52   IN EFI_SMM_ACCESS2_PROTOCOL  *This
  53   );
  54
  55 /**
  56   Inhibits access to the SMRAM.
  57
  58   This function "closes" SMRAM so that it is not visible while outside of SMM. The function should
  59   return EFI_UNSUPPORTED if the hardware does not support hiding of SMRAM.
  60
  61   @param[in] This           The EFI_SMM_ACCESS2_PROTOCOL instance.
  62
  63   @retval EFI_SUCCESS       The operation was successful.
  64   @retval EFI_UNSUPPORTED   The system does not support opening and closing of SMRAM.
  65   @retval EFI_DEVICE_ERROR  SMRAM cannot be closed.
  66 **/
  67 typedef
  68 EFI_STATUS
  69 (EFIAPI *EFI_SMM_CLOSE2)(
  70   IN EFI_SMM_ACCESS2_PROTOCOL  *This
  71   );
  72
  73 /**
  74   Inhibits access to the SMRAM.
  75
  76   This function prohibits access to the SMRAM region.  This function is usually implemented such
  77   that it is a write-once operation.
  78
  79   @param[in] This          The EFI_SMM_ACCESS2_PROTOCOL instance.
  80
  81   @retval EFI_SUCCESS      The device was successfully locked.
  82   @retval EFI_UNSUPPORTED  The system does not support locking of SMRAM.
  83 **/
  84 typedef
  85 EFI_STATUS
  86 (EFIAPI *EFI_SMM_LOCK2)(
  87   IN EFI_SMM_ACCESS2_PROTOCOL  *This
  88   );
  89
  90 /**
  91   Queries the memory controller for the possible regions that will support SMRAM.
  92
  93   @param[in]     This           The EFI_SMM_ACCESS2_PROTOCOL instance.
  94   @param[in,out] SmramMapSize   A pointer to the size, in bytes, of the SmramMemoryMap buffer.
  95   @param[in,out] SmramMap       A pointer to the buffer in which firmware places the current memory map.
  96
  97   @retval EFI_SUCCESS           The chipset supported the given resource.
  98   @retval EFI_BUFFER_TOO_SMALL  The SmramMap parameter was too small.  The current buffer size
  99                                 needed to hold the memory map is returned in SmramMapSize.
 100 **/
 101 typedef
 102 EFI_STATUS
 103 (EFIAPI *EFI_SMM_CAPABILITIES2)(
 104   IN CONST EFI_SMM_ACCESS2_PROTOCOL  *This,
 105   IN OUT UINTN                       *SmramMapSize,
 106   IN OUT EFI_SMRAM_DESCRIPTOR        *SmramMap
 107   );
 108
 109 ///
 110 ///  EFI SMM Access2 Protocol is used to control the visibility of the SMRAM on the platform.
 111 ///  It abstracts the location and characteristics of SMRAM.  The expectation is
 112 ///  that the north bridge or memory controller would publish this protocol.
 113 ///
 114 struct _EFI_SMM_ACCESS2_PROTOCOL {
 115   EFI_SMM_OPEN2          Open;
 116   EFI_SMM_CLOSE2         Close;
 117   EFI_SMM_LOCK2          Lock;
 118   EFI_SMM_CAPABILITIES2  GetCapabilities;
 119   ///
 120   /// Indicates the current state of the SMRAM. Set to TRUE if SMRAM is locked.
 121   ///
 122   BOOLEAN               LockState;
 123   ///
 124   /// Indicates the current state of the SMRAM. Set to TRUE if SMRAM is open.
 125   ///
 126   BOOLEAN               OpenState;
 127 };
 128
 129 extern EFI_GUID gEfiSmmAccess2ProtocolGuid;
 130
 131 #endif
 132