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EDK2 doxygen online documents - Firmware Encoding Index
Functions | Variables

PcAtChipsetPkg/8254TimerDxe/Timer.c File Reference

#include "Timer.h"

Go to the source code of this file.

Functions

VOID SetPitCount (IN UINT16 Count)
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_PROTOCOLmCpu
EFI_LEGACY_8259_PROTOCOLmLegacy8259
EFI_TIMER_NOTIFY mTimerNotifyFunction
volatile UINT64 mTimerPeriod = 0

Detailed Description

Timer Architectural Protocol as defined in the DXE CIS

Copyright (c) 2005 - 2010, 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.

Definition in file Timer.c.


Function Documentation

VOID SetPitCount ( IN UINT16  Count)

Sets the counter value for Timer #0 in a legacy 8254 timer.

Parameters:
CountThe 16-bit counter value to program into Timer #0 of the legacy 8254 timer.

Definition at line 62 of file Timer.c.

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:
ThisThe EFI_TIMER_ARCH_PROTOCOL instance.
Return values:
EFI_SUCCESSThe soft timer interrupt was generated.
EFI_UNSUPPORTEDTThe platform does not support the generation of soft timer interrupts.

Definition at line 295 of file Timer.c.

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:
ThisThe EFI_TIMER_ARCH_PROTOCOL instance.
TimerPeriodA pointer to the timer period to retrieve in 100 ns units. If 0 is returned, then the timer is currently disabled.
Return values:
EFI_SUCCESSThe timer period was returned in TimerPeriod.
EFI_INVALID_PARAMETERTimerPeriod is NULL.

Definition at line 262 of file Timer.c.

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

Initialize the Timer Architectural Protocol driver

Parameters:
ImageHandleImageHandle of the loaded driver
SystemTablePointer to the System Table
Return values:
EFI_SUCCESSTimer Architectural Protocol created
EFI_OUT_OF_RESOURCESNot enough resources available to initialize driver.
EFI_DEVICE_ERRORA device error occured attempting to initialize the driver.

Definition at line 342 of file Timer.c.

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:
ThisThe EFI_TIMER_ARCH_PROTOCOL instance.
NotifyFunctionThe 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_SUCCESSThe timer handler was registered.
EFI_UNSUPPORTEDThe platform does not support timer interrupts.
EFI_ALREADY_STARTEDNotifyFunction is not NULL, and a handler is already registered.
EFI_INVALID_PARAMETERNotifyFunction is NULL, and a handler was not previously registered.
EFI_DEVICE_ERRORThe timer handler could not be registered.

Definition at line 133 of file Timer.c.

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:
ThisThe EFI_TIMER_ARCH_PROTOCOL instance.
TimerPeriodThe 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_SUCCESSThe timer period was changed.
EFI_UNSUPPORTEDThe platform cannot change the period of the timer interrupt.
EFI_DEVICE_ERRORThe timer period could not be changed due to a device error.

Definition at line 184 of file Timer.c.

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

8254 Timer #0 Interrupt Handler.

Parameters:
InterruptTypeThe type of interrupt that occured
SystemContextA pointer to the system context when the interrupt occured

Definition at line 79 of file Timer.c.


Variable Documentation

Definition at line 35 of file Timer.c.

Definition at line 40 of file Timer.c.

Definition at line 20 of file Timer.c.

Definition at line 46 of file Timer.c.

volatile UINT64 mTimerPeriod = 0

Definition at line 51 of file Timer.c.

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