| /** @file |
| EFI Timestamp Protocol as defined in UEFI2.4 Specification. |
| Used to provide a platform independent interface for retrieving a high resolution timestamp counter. |
| |
| Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR> |
| SPDX-License-Identifier: BSD-2-Clause-Patent |
| |
| @par Revision Reference: |
| This Protocol is introduced in UEFI Specification 2.4 |
| |
| **/ |
| |
| #ifndef __EFI_TIME_STAMP_PROTOCOL_H__ |
| #define __EFI_TIME_STAMP_PROTOCOL_H__ |
| |
| |
| #define EFI_TIMESTAMP_PROTOCOL_GUID \ |
| { 0xafbfde41, 0x2e6e, 0x4262, {0xba, 0x65, 0x62, 0xb9, 0x23, 0x6e, 0x54, 0x95 } } |
| |
| /// |
| /// Declare forward reference for the Time Stamp Protocol |
| /// |
| typedef struct _EFI_TIMESTAMP_PROTOCOL EFI_TIMESTAMP_PROTOCOL; |
| |
| /// |
| /// EFI_TIMESTAMP_PROPERTIES |
| /// |
| typedef struct { |
| /// |
| /// The frequency of the timestamp counter in Hz. |
| /// |
| UINT64 Frequency; |
| /// |
| /// The value that the timestamp counter ends with immediately before it rolls over. |
| /// For example, a 64-bit free running counter would have an EndValue of 0xFFFFFFFFFFFFFFFF. |
| /// A 24-bit free running counter would have an EndValue of 0xFFFFFF. |
| /// |
| UINT64 EndValue; |
| } EFI_TIMESTAMP_PROPERTIES; |
| |
| /** |
| Retrieves the current value of a 64-bit free running timestamp counter. |
| |
| The counter shall count up in proportion to the amount of time that has passed. The counter value |
| will always roll over to zero. The properties of the counter can be retrieved from GetProperties(). |
| The caller should be prepared for the function to return the same value twice across successive calls. |
| The counter value will not go backwards other than when wrapping, as defined by EndValue in GetProperties(). |
| The frequency of the returned timestamp counter value must remain constant. Power management operations that |
| affect clocking must not change the returned counter frequency. The quantization of counter value updates may |
| vary as long as the value reflecting time passed remains consistent. |
| |
| @param None. |
| |
| @retval The current value of the free running timestamp counter. |
| |
| **/ |
| typedef |
| UINT64 |
| (EFIAPI *TIMESTAMP_GET)( |
| VOID |
| ); |
| |
| /** |
| Obtains timestamp counter properties including frequency and value limits. |
| |
| @param[out] Properties The properties of the timestamp counter. |
| |
| @retval EFI_SUCCESS The properties were successfully retrieved. |
| @retval EFI_DEVICE_ERROR An error occurred trying to retrieve the properties of the timestamp |
| counter subsystem. Properties is not pedated. |
| @retval EFI_INVALID_PARAMETER Properties is NULL. |
| |
| **/ |
| typedef |
| EFI_STATUS |
| (EFIAPI *TIMESTAMP_GET_PROPERTIES)( |
| OUT EFI_TIMESTAMP_PROPERTIES *Properties |
| ); |
| |
| |
| |
| /// |
| /// EFI_TIMESTAMP_PROTOCOL |
| /// The protocol provides a platform independent interface for retrieving a high resolution |
| /// timestamp counter. |
| /// |
| struct _EFI_TIMESTAMP_PROTOCOL { |
| TIMESTAMP_GET GetTimestamp; |
| TIMESTAMP_GET_PROPERTIES GetProperties; |
| }; |
| |
| extern EFI_GUID gEfiTimestampProtocolGuid; |
| |
| #endif |
| |