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/** @file
Timer Architectural Protocol as defined in PI Specification VOLUME 2 DXE
This code is used to provide the timer tick for the DXE core.
Copyright (c) 2006 - 2008, 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.
**/
#ifndef __ARCH_PROTOCOL_TIMER_H__
#define __ARCH_PROTOCOL_TIMER_H__
//
// Global ID for the Timer Architectural Protocol
//
#define EFI_TIMER_ARCH_PROTOCOL_GUID \
{ 0x26baccb3, 0x6f42, 0x11d4, {0xbc, 0xe7, 0x0, 0x80, 0xc7, 0x3c, 0x88, 0x81 } }
//
// Declare forward reference for the Timer Architectural Protocol
//
typedef struct _EFI_TIMER_ARCH_PROTOCOL EFI_TIMER_ARCH_PROTOCOL;
/**
This function of this type is called when a timer interrupt fires. This
function executes at TPL_HIGH_LEVEL. The DXE Core will register a funtion
of tyis type to be called for the timer interrupt, so it can know how much
time has passed. This information is used to signal timer based events.
@param Time Time since the last timer interrupt in 100 ns units. This will
typically be TimerPeriod, but if a timer interrupt is missed, and the
EFI_TIMER_ARCH_PROTOCOL driver can detect missed interrupts, then Time
will contain the actual amount of time since the last interrupt.
None.
**/
typedef
VOID
(EFIAPI *EFI_TIMER_NOTIFY)(
IN UINT64 Time
);
/**
This function registers the handler NotifyFunction so it is called every time
the timer interrupt fires. It also passes the amount of time since the last
handler call to the NotifyFunction. If NotifyFunction is NULL, then the
handler is unregistered. If the handler is registered, then EFI_SUCCESS is
returned. If the CPU does not support registering a timer interrupt handler,
then EFI_UNSUPPORTED is returned. If an attempt is made to register a handler
when a handler is already registered, then EFI_ALREADY_STARTED is returned.
If an attempt is made to unregister a handler when a handler is not registered,
then EFI_INVALID_PARAMETER is returned. If an error occurs attempting to
register the NotifyFunction with the timer interrupt, then EFI_DEVICE_ERROR
is returned.
@param This The EFI_TIMER_ARCH_PROTOCOL instance.
@param NotifyFunction The function to call when a timer interrupt fires. This
function executes at TPL_HIGH_LEVEL. The DXE Core will
register a handler for the timer interrupt, so it can know
how much time has passed. This information is used to
signal timer based events. NULL will unregister the handler.
@retval EFI_SUCCESS The timer handler was registered.
@retval EFI_UNSUPPORTED The platform does not support timer interrupts.
@retval EFI_ALREADY_STARTED NotifyFunction is not NULL, and a handler is already
registered.
@retval EFI_INVALID_PARAMETER NotifyFunction is NULL, and a handler was not
previously registered.
@retval EFI_DEVICE_ERROR The timer handler could not be registered.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_TIMER_REGISTER_HANDLER)(
IN EFI_TIMER_ARCH_PROTOCOL *This,
IN EFI_TIMER_NOTIFY NotifyFunction
);
/**
This function adjusts the period of timer interrupts to the value specified
by TimerPeriod. If the timer period is updated, then the selected timer
period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned. If
the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
If an error occurs while attempting to update the timer period, then the
timer hardware will be put back in its state prior to this call, and
EFI_DEVICE_ERROR is returned. If TimerPeriod is 0, then the timer interrupt
is disabled. This is not the same as disabling the CPU's interrupts.
Instead, it must either turn off the timer hardware, or it must adjust the
interrupt controller so that a CPU interrupt is not generated when the timer
interrupt fires.
@param This The EFI_TIMER_ARCH_PROTOCOL instance.
@param TimerPeriod The rate to program the timer interrupt in 100 nS units. If
the timer hardware is not programmable, then EFI_UNSUPPORTED is
returned. If the timer is programmable, then the timer period
will be rounded up to the nearest timer period that is supported
by the timer hardware. If TimerPeriod is set to 0, then the
timer interrupts will be disabled.
@retval EFI_SUCCESS The timer period was changed.
@retval EFI_UNSUPPORTED The platform cannot change the period of the timer interrupt.
@retval EFI_DEVICE_ERROR The timer period could not be changed due to a device error.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_TIMER_SET_TIMER_PERIOD)(
IN EFI_TIMER_ARCH_PROTOCOL *This,
IN UINT64 TimerPeriod
);
/**
This function retrieves the period of timer interrupts in 100 ns units,
returns that value in TimerPeriod, and returns EFI_SUCCESS. If TimerPeriod
is NULL, then EFI_INVALID_PARAMETER is returned. If a TimerPeriod of 0 is
returned, then the timer is currently disabled.
@param This The EFI_TIMER_ARCH_PROTOCOL instance.
@param TimerPeriod A pointer to the timer period to retrieve in 100 ns units. If
0 is returned, then the timer is currently disabled.
@retval EFI_SUCCESS The timer period was returned in TimerPeriod.
@retval EFI_INVALID_PARAMETER TimerPeriod is NULL.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_TIMER_GET_TIMER_PERIOD)(
IN EFI_TIMER_ARCH_PROTOCOL *This,
OUT UINT64 *TimerPeriod
);
/**
This function generates a soft timer interrupt. If the platform does not support soft
timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned.
If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()
service, then a soft timer interrupt will be generated. If the timer interrupt is
enabled when this service is called, then the registered handler will be invoked. The
registered handler should not be able to distinguish a hardware-generated timer
interrupt from a software-generated timer interrupt.
@param This The EFI_TIMER_ARCH_PROTOCOL instance.
@retval EFI_SUCCESS The soft timer interrupt was generated.
@retval EFI_UNSUPPORTEDT The platform does not support the generation of soft timer interrupts.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_TIMER_GENERATE_SOFT_INTERRUPT)(
IN EFI_TIMER_ARCH_PROTOCOL *This
);
/**
Interface stucture for the Timer Architectural Protocol.
@par Protocol Description:
This protocol provides the services to initialize a periodic timer
interrupt, and to register a handler that is called each time the timer
interrupt fires. It may also provide a service to adjust the rate of the
periodic timer interrupt. When a timer interrupt occurs, the handler is
passed the amount of time that has passed since the previous timer
interrupt.
@param RegisterHandler
Registers a handler that will be called each time the
timer interrupt fires. TimerPeriod defines the minimum
time between timer interrupts, so TimerPeriod will also
be the minimum time between calls to the registered
handler.
@param SetTimerPeriod
Sets the period of the timer interrupt in 100 nS units.
This function is optional, and may return EFI_UNSUPPORTED.
If this function is supported, then the timer period will
be rounded up to the nearest supported timer period.
@param GetTimerPeriod
Retrieves the period of the timer interrupt in 100 nS units.
@param GenerateSoftInterrupt
Generates a soft timer interrupt that simulates the firing of
the timer interrupt. This service can be used to invoke the
registered handler if the timer interrupt has been masked for
a period of time.
**/
struct _EFI_TIMER_ARCH_PROTOCOL {
EFI_TIMER_REGISTER_HANDLER RegisterHandler;
EFI_TIMER_SET_TIMER_PERIOD SetTimerPeriod;
EFI_TIMER_GET_TIMER_PERIOD GetTimerPeriod;
EFI_TIMER_GENERATE_SOFT_INTERRUPT GenerateSoftInterrupt;
};
extern EFI_GUID gEfiTimerArchProtocolGuid;
#endif
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