TimerDxe.c File Reference

#include <PiDxe.h>
#include <Library/ArmLib.h>
#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/UefiLib.h>
#include <Library/PcdLib.h>
#include <Library/IoLib.h>
#include <Library/ArmGenericTimerCounterLib.h>
#include <Protocol/Timer.h>
#include <Protocol/HardwareInterrupt.h>

Go to the source code of this file.

Functions
EFI_STATUS EFIAPI	TimerDriverRegisterHandler (IN EFI_TIMER_ARCH_PROTOCOL *This, IN EFI_TIMER_NOTIFY NotifyFunction)
VOID EFIAPI	ExitBootServicesEvent (IN EFI_EVENT Event, IN VOID *Context)
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)
VOID EFIAPI	TimerInterruptHandler (IN HARDWARE_INTERRUPT_SOURCE Source, IN EFI_SYSTEM_CONTEXT SystemContext)
EFI_STATUS EFIAPI	TimerInitialize (IN EFI_HANDLE ImageHandle, IN EFI_SYSTEM_TABLE *SystemTable)

Variables
EFI_TIMER_NOTIFY	mTimerNotifyFunction = (EFI_TIMER_NOTIFY)NULL
EFI_EVENT	EfiExitBootServicesEvent = (EFI_EVENT)NULL
UINT64	mTimerPeriod = 0
UINT64	mTimerTicks = 0
UINT64	mElapsedPeriod = 1
EFI_HARDWARE_INTERRUPT_PROTOCOL *	gInterrupt = NULL
EFI_TIMER_ARCH_PROTOCOL	gTimer

Detailed Description

Timer Architecture Protocol driver of the ARM flavor

Copyright (c) 2011-2021, Arm Limited. All rights reserved.

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

Definition in file TimerDxe.c.

Function Documentation

ExitBootServicesEvent()

VOID EFIAPI ExitBootServicesEvent	(	IN EFI_EVENT	Event,
		IN VOID *	Context
	)

Disable the timer

Definition at line 92 of file TimerDxe.c.

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 223 of file TimerDxe.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 193 of file TimerDxe.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 69 of file TimerDxe.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 130 of file TimerDxe.c.

TimerInitialize()

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

Initialize the state information for the Timer Architectural Protocol and the Timer Debug support protocol that allows the debugger to break into a running program.

Parameters

ImageHandle	of the loaded driver
SystemTable	Pointer to the System Table

Return values

EFI_SUCCESS	Protocol registered
EFI_OUT_OF_RESOURCES	Cannot allocate protocol data structure
EFI_DEVICE_ERROR	Hardware problems

Definition at line 354 of file TimerDxe.c.

TimerInterruptHandler()

VOID EFIAPI TimerInterruptHandler	(	IN HARDWARE_INTERRUPT_SOURCE	Source,
		IN EFI_SYSTEM_CONTEXT	SystemContext
	)

C Interrupt Handler called in the interrupt context when Source interrupt is active.

Parameters

Source	Source of the interrupt. Hardware routing off a specific platform defines what source means.
SystemContext	Pointer to system register context. Mostly used by debuggers and will update the system context after the return from the interrupt if modified. Don't change these values unless you know what you are doing

Definition at line 286 of file TimerDxe.c.

Variable Documentation

EfiExitBootServicesEvent

EFI_EVENT EfiExitBootServicesEvent = (EFI_EVENT)NULL

Definition at line 27 of file TimerDxe.c.

gInterrupt

EFI_HARDWARE_INTERRUPT_PROTOCOL* gInterrupt = NULL

Definition at line 37 of file TimerDxe.c.

gTimer

EFI_TIMER_ARCH_PROTOCOL gTimer

Initial value:

= {
  TimerDriverRegisterHandler,
  TimerDriverSetTimerPeriod,
  TimerDriverGetTimerPeriod,
  TimerDriverGenerateSoftInterrupt
}

Interface structure for the Timer Architectural Protocol.

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.

Parameters

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.
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.
GetTimerPeriod	Retrieves the period of the timer interrupt in 100 nS units.
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.

Definition at line 264 of file TimerDxe.c.

mElapsedPeriod

UINT64 mElapsedPeriod = 1

Definition at line 34 of file TimerDxe.c.

mTimerNotifyFunction

EFI_TIMER_NOTIFY mTimerNotifyFunction = (EFI_TIMER_NOTIFY)NULL

Definition at line 26 of file TimerDxe.c.

mTimerPeriod

UINT64 mTimerPeriod = 0

Definition at line 30 of file TimerDxe.c.

mTimerTicks

UINT64 mTimerTicks = 0

Definition at line 32 of file TimerDxe.c.