Timer Architectural Protocol as defined in the DXE CIS
Copyright (c) 2005 - 2018, Intel Corporation. All rights reserved.
SPDX-License-Identifier: BSD-2-Clause-Patent
Definition in file Timer.c.
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 292 of file Timer.c.
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 131 of file Timer.c.
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 182 of file Timer.c.
1.9.6