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/** @file
Metronome Architectural Protocol as defined in DXE CIS
This code abstracts the DXE core to provide delay services.
Copyright (c) 2006, Intel Corporation
All rights reserved. This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
Module Name: Metronome.h
@par Revision Reference:
Version 0.91B.
**/
#ifndef __ARCH_PROTOCOL_METRONOME_H__
#define __ARCH_PROTOCOL_METRONOME_H__
//
// Global ID for the Metronome Architectural Protocol
//
#define EFI_METRONOME_ARCH_PROTOCOL_GUID \
{ 0x26baccb2, 0x6f42, 0x11d4, {0xbc, 0xe7, 0x0, 0x80, 0xc7, 0x3c, 0x88, 0x81 } }
//
// Declare forward reference for the Metronome Architectural Protocol
//
typedef struct _EFI_METRONOME_ARCH_PROTOCOL EFI_METRONOME_ARCH_PROTOCOL;
/**
The WaitForTick() function waits for the number of ticks specified by
TickNumber from a known time source in the platform. If TickNumber of
ticks are detected, then EFI_SUCCESS is returned. The actual time passed
between entry of this function and the first tick is between 0 and
TickPeriod 100 nS units. If you want to guarantee that at least TickPeriod
time has elapsed, wait for two ticks. This function waits for a hardware
event to determine when a tick occurs. It is possible for interrupt
processing, or exception processing to interrupt the execution of the
WaitForTick() function. Depending on the hardware source for the ticks, it
is possible for a tick to be missed. This function cannot guarantee that
ticks will not be missed. If a timeout occurs waiting for the specified
number of ticks, then EFI_TIMEOUT is returned.
@param This The EFI_METRONOME_ARCH_PROTOCOL instance.
@param TickNumber Number of ticks to wait.
@retval EFI_SUCCESS The wait for the number of ticks specified by TickNumber
succeeded.
@retval EFI_TIMEOUT A timeout occurred waiting for the specified number of ticks.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_METRONOME_WAIT_FOR_TICK) (
IN EFI_METRONOME_ARCH_PROTOCOL *This,
IN UINT32 TickNumber
);
//
//
/**
Interface stucture for the Metronome Architectural Protocol.
@par Protocol Description:
This protocol provides access to a known time source in the platform to the
core. The core uses this known time source to produce core services that
require calibrated delays.
@param WaitForTick
Waits for a specified number of ticks from a known time source
in the platform. The actual time passed between entry of this
function and the first tick is between 0 and TickPeriod 100 nS
units. If you want to guarantee that at least TickPeriod time
has elapsed, wait for two ticks.
@param TickPeriod
The period of platform's known time source in 100 nS units.
This value on any platform must be at least 10 uS, and must not
exceed 200 uS. The value in this field is a constant that must
not be modified after the Metronome architectural protocol is
installed. All consumers must treat this as a read-only field.
**/
struct _EFI_METRONOME_ARCH_PROTOCOL {
EFI_METRONOME_WAIT_FOR_TICK WaitForTick;
UINT32 TickPeriod;
};
extern EFI_GUID gEfiMetronomeArchProtocolGuid;
#endif
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