#include <PiDxe.h>
#include <Protocol/Cpu.h>
#include <Protocol/Timer.h>
#include <Library/IoLib.h>
#include <Library/PcdLib.h>
#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/LocalApicLib.h>
#include <Library/IoApicLib.h>
#include <Register/LocalApic.h>
#include <Register/IoApic.h>
#include <Register/Hpet.h>

Macros
#define	HPET_INVALID_TIMER_INDEX 0xff

Functions
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)

UINT64	HpetRead (IN UINTN Offset)

UINT64	HpetWrite (IN UINTN Offset, IN UINT64 Value)

VOID	HpetEnable (IN BOOLEAN Enable)

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

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 = NULL

EFI_TIMER_NOTIFY	mTimerNotifyFunction = NULL

UINT64	mTimerPeriod = 0

UINT64	mTimerCount

UINT64	mCounterMask

volatile UINT64	mPreviousMainCounter

volatile UINT64	mPreviousComparator

UINTN	mTimerIndex

UINT32	mTimerIrq

HPET_GENERAL_CAPABILITIES_ID_REGISTER	mHpetGeneralCapabilities

HPET_GENERAL_CONFIGURATION_REGISTER	mHpetGeneralConfiguration

HPET_TIMER_CONFIGURATION_REGISTER	mTimerConfiguration

volatile UINTN	mNumTicks

Detailed Description

Timer Architectural Protocol module using High Precision Event Timer (HPET)

Copyright (c) 2011 - 2018, Intel Corporation. All rights reserved.
SPDX-License-Identifier: BSD-2-Clause-Patent

Definition in file HpetTimer.c.

Macro Definition Documentation

◆ HPET_INVALID_TIMER_INDEX

#define HPET_INVALID_TIMER_INDEX 0xff

Define value for an invalid HPET Timer index.

Definition at line 29 of file HpetTimer.c.

Function Documentation

◆ HpetEnable()

VOID HpetEnable ( IN BOOLEAN Enable )

Enable or disable the main counter in the HPET Timer.

Parameters

Enable If TRUE, then enable the main counter in the HPET Timer. If FALSE, then disable the main counter in the HPET Timer.

Definition at line 270 of file HpetTimer.c.

◆ HpetRead()

UINT64 HpetRead ( IN UINTN Offset )

Read a 64-bit register from the HPET

Parameters

Offset Specifies the offset of the HPET register to read.

Returns: The 64-bit value read from the HPET register specified by Offset.

Definition at line 239 of file HpetTimer.c.

◆ HpetWrite()

UINT64 HpetWrite	(	IN UINTN	Offset,
		IN UINT64	Value
	)

Write a 64-bit HPET register.

Parameters

Offset	Specifies the offset of the HPET register to write.
Value	Specifies the value to write to the HPET register specified by Offset.

Returns: The 64-bit value written to HPET register specified by Offset.

Definition at line 255 of file HpetTimer.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 689 of file HpetTimer.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 657 of file HpetTimer.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 768 of file HpetTimer.c.

◆ TimerDriverRegisterHandler()

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

Timer Architectural Protocol function prototypes. 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.

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 442 of file HpetTimer.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 495 of file HpetTimer.c.

◆ TimerInterruptHandler()

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

The interrupt handler for the HPET timer. This handler clears the HPET interrupt and computes the amount of time that has passed since the last HPET timer interrupt. If a notification function is registered, then the amount of time since the last HPET interrupt is passed to that notification function in 100 ns units. The HPET time is updated to generate another interrupt in the required time period.

Parameters

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

Definition at line 290 of file HpetTimer.c.

Variable Documentation

◆ mCounterMask

UINT64 mCounterMask

Mask used for counter and comparator calculations to adjust for a 32-bit or 64-bit counter.

Definition at line 187 of file HpetTimer.c.

◆ mCpu

EFI_CPU_ARCH_PROTOCOL* mCpu = NULL

Pointer to the CPU Architectural Protocol instance.

Definition at line 167 of file HpetTimer.c.

◆ mHpetGeneralCapabilities

HPET_GENERAL_CAPABILITIES_ID_REGISTER mHpetGeneralCapabilities

Cached state of the HPET General Capabilities register managed by this driver. Caching the state reduces the number of times the configuration register is read.

Definition at line 210 of file HpetTimer.c.

◆ mHpetGeneralConfiguration

HPET_GENERAL_CONFIGURATION_REGISTER mHpetGeneralConfiguration

Cached state of the HPET General Configuration register managed by this driver. Caching the state reduces the number of times the configuration register is read.

Definition at line 216 of file HpetTimer.c.

◆ mNumTicks

volatile UINTN mNumTicks

Counts the number of HPET Timer interrupts processed by this driver. Only required for debug.

Definition at line 229 of file HpetTimer.c.

◆ mPreviousComparator

volatile UINT64 mPreviousComparator

Definition at line 194 of file HpetTimer.c.

◆ mPreviousMainCounter

volatile UINT64 mPreviousMainCounter

The HPET main counter value from the most recent HPET timer interrupt.

Definition at line 192 of file HpetTimer.c.

◆ mTimer

EFI_TIMER_ARCH_PROTOCOL mTimer

Initial value:

= {
  TimerDriverRegisterHandler,
  TimerDriverSetTimerPeriod,
  TimerDriverGetTimerPeriod,
  TimerDriverGenerateSoftInterrupt
}

The Timer Architectural Protocol that this driver produces.

Definition at line 157 of file HpetTimer.c.

◆ mTimerConfiguration

HPET_TIMER_CONFIGURATION_REGISTER mTimerConfiguration

Cached state of the Configuration register for the HPET Timer managed by this driver. Caching the state reduces the number of times the configuration register is read.

Definition at line 223 of file HpetTimer.c.

◆ mTimerCount

UINT64 mTimerCount

The number of HPET timer ticks required for the current HPET rate specified by mTimerPeriod.

Definition at line 182 of file HpetTimer.c.

◆ mTimerHandle

EFI_HANDLE mTimerHandle = NULL

The handle onto which the Timer Architectural Protocol will be installed.

Definition at line 152 of file HpetTimer.c.

◆ mTimerIndex

UINTN mTimerIndex

The index of the HPET timer being managed by this driver.

Definition at line 199 of file HpetTimer.c.

◆ mTimerIrq

UINT32 mTimerIrq

The I/O APIC IRQ that the HPET Timer is mapped if I/O APIC mode is used.

Definition at line 204 of file HpetTimer.c.

◆ mTimerNotifyFunction

EFI_TIMER_NOTIFY mTimerNotifyFunction = NULL

The notification function to call on every timer interrupt.

Definition at line 172 of file HpetTimer.c.

◆ mTimerPeriod

UINT64 mTimerPeriod = 0

The current period of the HPET timer interrupt in 100 ns units.

Definition at line 177 of file HpetTimer.c.

Macros

Functions

Variables

Detailed Description

Macro Definition Documentation

◆ HPET_INVALID_TIMER_INDEX

Function Documentation

◆ HpetEnable()

◆ HpetRead()

◆ HpetWrite()

◆ TimerDriverGenerateSoftInterrupt()

◆ TimerDriverGetTimerPeriod()

◆ TimerDriverInitialize()

◆ TimerDriverRegisterHandler()

◆ TimerDriverSetTimerPeriod()

◆ TimerInterruptHandler()

Variable Documentation

◆ mCounterMask

◆ mCpu

◆ mHpetGeneralCapabilities

◆ mHpetGeneralConfiguration

◆ mNumTicks

◆ mPreviousComparator

◆ mPreviousMainCounter

◆ mTimer

◆ mTimerConfiguration

◆ mTimerCount

◆ mTimerHandle

◆ mTimerIndex

◆ mTimerIrq

◆ mTimerNotifyFunction

◆ mTimerPeriod