| /** @file |
| EFI MM Access Protocol as defined in the PI 1.5 specification. |
| |
| This protocol is used to control the visibility of the MMRAM on the platform. |
| It abstracts the location and characteristics of MMRAM. The expectation is |
| that the north bridge or memory controller would publish this protocol. |
| |
| The principal functionality found in the memory controller includes the following: |
| - Exposing the MMRAM to all non-MM agents, or the "open" state |
| - Shrouding the MMRAM to all but the MM agents, or the "closed" state |
| - Preserving the system integrity, or "locking" the MMRAM, such that the settings cannot be |
| perturbed by either boot service or runtime agents |
| |
| Copyright (c) 2017, Intel Corporation. All rights reserved.<BR> |
| SPDX-License-Identifier: BSD-2-Clause-Patent |
| |
| **/ |
| |
| #ifndef _MM_ACCESS_H_ |
| #define _MM_ACCESS_H_ |
| |
| #define EFI_MM_ACCESS_PROTOCOL_GUID \ |
| { \ |
| 0xc2702b74, 0x800c, 0x4131, {0x87, 0x46, 0x8f, 0xb5, 0xb8, 0x9c, 0xe4, 0xac } \ |
| } |
| |
| |
| typedef struct _EFI_MM_ACCESS_PROTOCOL EFI_MM_ACCESS_PROTOCOL; |
| |
| /** |
| Opens the MMRAM area to be accessible by a boot-service driver. |
| |
| This function "opens" MMRAM so that it is visible while not inside of MM. The function should |
| return EFI_UNSUPPORTED if the hardware does not support hiding of MMRAM. The function |
| should return EFI_DEVICE_ERROR if the MMRAM configuration is locked. |
| |
| @param[in] This The EFI_MM_ACCESS_PROTOCOL instance. |
| |
| @retval EFI_SUCCESS The operation was successful. |
| @retval EFI_UNSUPPORTED The system does not support opening and closing of MMRAM. |
| @retval EFI_DEVICE_ERROR MMRAM cannot be opened, perhaps because it is locked. |
| **/ |
| typedef |
| EFI_STATUS |
| (EFIAPI *EFI_MM_OPEN)( |
| IN EFI_MM_ACCESS_PROTOCOL *This |
| ); |
| |
| /** |
| Inhibits access to the MMRAM. |
| |
| This function "closes" MMRAM so that it is not visible while outside of MM. The function should |
| return EFI_UNSUPPORTED if the hardware does not support hiding of MMRAM. |
| |
| @param[in] This The EFI_MM_ACCESS_PROTOCOL instance. |
| |
| @retval EFI_SUCCESS The operation was successful. |
| @retval EFI_UNSUPPORTED The system does not support opening and closing of MMRAM. |
| @retval EFI_DEVICE_ERROR MMRAM cannot be closed. |
| **/ |
| typedef |
| EFI_STATUS |
| (EFIAPI *EFI_MM_CLOSE)( |
| IN EFI_MM_ACCESS_PROTOCOL *This |
| ); |
| |
| /** |
| Inhibits access to the MMRAM. |
| |
| This function prohibits access to the MMRAM region. This function is usually implemented such |
| that it is a write-once operation. |
| |
| @param[in] This The EFI_MM_ACCESS_PROTOCOL instance. |
| |
| @retval EFI_SUCCESS The device was successfully locked. |
| @retval EFI_UNSUPPORTED The system does not support locking of MMRAM. |
| **/ |
| typedef |
| EFI_STATUS |
| (EFIAPI *EFI_MM_LOCK)( |
| IN EFI_MM_ACCESS_PROTOCOL *This |
| ); |
| |
| /** |
| Queries the memory controller for the possible regions that will support MMRAM. |
| |
| @param[in] This The EFI_MM_ACCESS_PROTOCOL instance. |
| @param[in,out] MmramMapSize A pointer to the size, in bytes, of the MmramMemoryMap buffer. |
| @param[in,out] MmramMap A pointer to the buffer in which firmware places the current memory map. |
| |
| @retval EFI_SUCCESS The chipset supported the given resource. |
| @retval EFI_BUFFER_TOO_SMALL The MmramMap parameter was too small. The current buffer size |
| needed to hold the memory map is returned in MmramMapSize. |
| **/ |
| typedef |
| EFI_STATUS |
| (EFIAPI *EFI_MM_CAPABILITIES)( |
| IN CONST EFI_MM_ACCESS_PROTOCOL *This, |
| IN OUT UINTN *MmramMapSize, |
| IN OUT EFI_MMRAM_DESCRIPTOR *MmramMap |
| ); |
| |
| /// |
| /// EFI MM Access Protocol is used to control the visibility of the MMRAM on the platform. |
| /// It abstracts the location and characteristics of MMRAM. The platform should report all |
| /// MMRAM via EFI_MM_ACCESS_PROTOCOL. The expectation is that the north bridge or memory |
| /// controller would publish this protocol. |
| /// |
| struct _EFI_MM_ACCESS_PROTOCOL { |
| EFI_MM_OPEN Open; |
| EFI_MM_CLOSE Close; |
| EFI_MM_LOCK Lock; |
| EFI_MM_CAPABILITIES GetCapabilities; |
| /// |
| /// Indicates the current state of the MMRAM. Set to TRUE if MMRAM is locked. |
| /// |
| BOOLEAN LockState; |
| /// |
| /// Indicates the current state of the MMRAM. Set to TRUE if MMRAM is open. |
| /// |
| BOOLEAN OpenState; |
| }; |
| |
| extern EFI_GUID gEfiMmAccessProtocolGuid; |
| |
| #endif |
| |