LocalApicTimerDxe.c File Reference

#include <Library/NestedInterruptTplLib.h>
#include "LocalApicTimerDxe.h"

Go to the source code of this file.

Functions
VOID EFIAPI	TimerInterruptHandler (IN EFI_EXCEPTION_TYPE InterruptType, IN EFI_SYSTEM_CONTEXT SystemContext)
EFI_STATUS EFIAPI	TimerDriverRegisterHandler (IN EFI_TIMER_ARCH_PROTOCOL *This, IN EFI_TIMER_NOTIFY NotifyFunction)
EFI_STATUS EFIAPI	TimerDriverSetTimerPeriod (IN EFI_TIMER_ARCH_PROTOCOL *This, IN UINT64 TimerPeriod)
EFI_STATUS EFIAPI	TimerDriverGetTimerPeriod (IN EFI_TIMER_ARCH_PROTOCOL *This, OUT UINT64 *TimerPeriod)
EFI_STATUS EFIAPI	TimerDriverGenerateSoftInterrupt (IN EFI_TIMER_ARCH_PROTOCOL *This)
EFI_STATUS EFIAPI	TimerDriverInitialize (IN EFI_HANDLE ImageHandle, IN EFI_SYSTEM_TABLE *SystemTable)

Variables
EFI_HANDLE	mTimerHandle = NULL
EFI_TIMER_ARCH_PROTOCOL	mTimer
EFI_CPU_ARCH_PROTOCOL *	mCpu
EFI_TIMER_NOTIFY	mTimerNotifyFunction
volatile UINT64	mTimerPeriod = 0

Detailed Description

Timer Architectural Protocol as defined in the DXE CIS

Copyright (c) 2005 - 2018, Intel Corporation. All rights reserved.
Copyright (c) 2019, Citrix Systems, Inc.

SPDX-License-Identifier: BSD-2-Clause-Patent

Definition in file LocalApicTimerDxe.c.

Function Documentation

TimerDriverGenerateSoftInterrupt()

EFI_STATUS EFIAPI TimerDriverGenerateSoftInterrupt

(

IN EFI_TIMER_ARCH_PROTOCOL *

This

)

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.

Parameters

This	The EFI_TIMER_ARCH_PROTOCOL instance.

Return values

EFI_SUCCESS	The soft timer interrupt was generated.
EFI_UNSUPPORTED	The platform does not support the generation of soft timer interrupts.

Definition at line 268 of file LocalApicTimerDxe.c.

TimerDriverGetTimerPeriod()

EFI_STATUS EFIAPI TimerDriverGetTimerPeriod	(	IN EFI_TIMER_ARCH_PROTOCOL *	This,
		OUT 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.

Parameters

This	The EFI_TIMER_ARCH_PROTOCOL instance.
TimerPeriod	A pointer to the timer period to retrieve in 100 ns units. If 0 is returned, then the timer is currently disabled.

Return values

EFI_SUCCESS	The timer period was returned in TimerPeriod.
EFI_INVALID_PARAMETER	TimerPeriod is NULL.

Definition at line 235 of file LocalApicTimerDxe.c.

TimerDriverInitialize()

EFI_STATUS EFIAPI TimerDriverInitialize	(	IN EFI_HANDLE	ImageHandle,
		IN EFI_SYSTEM_TABLE *	SystemTable
	)

Initialize the Timer Architectural Protocol driver

Parameters

ImageHandle	ImageHandle of the loaded driver
SystemTable	Pointer to the System Table

Return values

EFI_SUCCESS	Timer Architectural Protocol created
EFI_OUT_OF_RESOURCES	Not enough resources available to initialize driver.
EFI_DEVICE_ERROR	A device error occurred attempting to initialize the driver.

Definition at line 308 of file LocalApicTimerDxe.c.

TimerDriverRegisterHandler()

EFI_STATUS EFIAPI TimerDriverRegisterHandler	(	IN EFI_TIMER_ARCH_PROTOCOL *	This,
		IN EFI_TIMER_NOTIFY	NotifyFunction
	)

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.

Parameters

This	The EFI_TIMER_ARCH_PROTOCOL instance.
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.

Return values

EFI_SUCCESS	The timer handler was registered.
EFI_UNSUPPORTED	The platform does not support timer interrupts.
EFI_ALREADY_STARTED	NotifyFunction is not NULL, and a handler is already registered.
EFI_INVALID_PARAMETER	NotifyFunction is NULL, and a handler was not previously registered.
EFI_DEVICE_ERROR	The timer handler could not be registered.

Definition at line 113 of file LocalApicTimerDxe.c.

TimerDriverSetTimerPeriod()

EFI_STATUS EFIAPI TimerDriverSetTimerPeriod	(	IN EFI_TIMER_ARCH_PROTOCOL *	This,
		IN UINT64	TimerPeriod
	)

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.

Parameters

This	The EFI_TIMER_ARCH_PROTOCOL instance.
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.

Return values

EFI_SUCCESS	The timer period was changed.
EFI_UNSUPPORTED	The platform cannot change the period of the timer interrupt.
EFI_DEVICE_ERROR	The timer period could not be changed due to a device error.

Definition at line 164 of file LocalApicTimerDxe.c.

TimerInterruptHandler()

VOID EFIAPI TimerInterruptHandler	(	IN EFI_EXCEPTION_TYPE	InterruptType,
		IN EFI_SYSTEM_CONTEXT	SystemContext
	)

Interrupt Handler.

Parameters

InterruptType	The type of interrupt that occurred
SystemContext	A pointer to the system context when the interrupt occurred

Definition at line 58 of file LocalApicTimerDxe.c.

Variable Documentation

mCpu

EFI_CPU_ARCH_PROTOCOL* mCpu

Definition at line 33 of file LocalApicTimerDxe.c.

mTimer

EFI_TIMER_ARCH_PROTOCOL mTimer

Initial value:

= {
  TimerDriverRegisterHandler,
  TimerDriverSetTimerPeriod,
  TimerDriverGetTimerPeriod,
  TimerDriverGenerateSoftInterrupt
}

Definition at line 23 of file LocalApicTimerDxe.c.

mTimerHandle

EFI_HANDLE mTimerHandle = NULL

Definition at line 18 of file LocalApicTimerDxe.c.

mTimerNotifyFunction

EFI_TIMER_NOTIFY mTimerNotifyFunction

Definition at line 39 of file LocalApicTimerDxe.c.

mTimerPeriod

volatile UINT64 mTimerPeriod = 0

Definition at line 44 of file LocalApicTimerDxe.c.