CpuTimerLib.c File Reference

#include <Base.h>
#include <Library/TimerLib.h>
#include <Library/BaseLib.h>
#include <Library/PcdLib.h>
#include <Library/DebugLib.h>
#include <Register/Cpuid.h>

Go to the source code of this file.

Functions
UINT64	InternalGetPerformanceCounterFrequency (VOID)
UINT64	CpuidCoreClockCalculateTscFrequency (VOID)
VOID	InternalCpuDelay (IN UINT64 Delay)
UINTN EFIAPI	MicroSecondDelay (IN UINTN MicroSeconds)
UINTN EFIAPI	NanoSecondDelay (IN UINTN NanoSeconds)
UINT64 EFIAPI	GetPerformanceCounter (VOID)
UINT64 EFIAPI	GetPerformanceCounterProperties (OUT UINT64 *StartValue OPTIONAL, OUT UINT64 *EndValue OPTIONAL)
UINT64 EFIAPI	GetTimeInNanoSecond (IN UINT64 Ticks)

Variables
GUID	mCpuCrystalFrequencyHobGuid

Detailed Description

CPUID Leaf 0x15 for Core Crystal Clock frequency instance of Timer Library.

Copyright (c) 2019 Intel Corporation. All rights reserved.
SPDX-License-Identifier: BSD-2-Clause-Patent

Definition in file CpuTimerLib.c.

Function Documentation

CpuidCoreClockCalculateTscFrequency()

UINT64 CpuidCoreClockCalculateTscFrequency

(

VOID

)

CPUID Leaf 0x15 for Core Crystal Clock Frequency.

The TSC counting frequency is determined by using CPUID leaf 0x15. Frequency in MHz = Core XTAL frequency * EBX/EAX. In newer flavors of the CPU, core xtal frequency is returned in ECX or 0 if not supported.

Returns

The number of TSC counts per second.

Definition at line 42 of file CpuTimerLib.c.

GetPerformanceCounter()

UINT64 EFIAPI GetPerformanceCounter

(

VOID

)

Retrieves the current value of a 64-bit free running performance counter.

Retrieves the current value of a 64-bit free running performance counter. The counter can either count up by 1 or count down by 1. If the physical performance counter counts by a larger increment, then the counter values must be translated. The properties of the counter can be retrieved from GetPerformanceCounterProperties().

Returns

The current value of the free running performance counter.

Definition at line 190 of file CpuTimerLib.c.

GetPerformanceCounterProperties()

UINT64 EFIAPI GetPerformanceCounterProperties	(	OUT UINT64 *StartValue	OPTIONAL,
		OUT UINT64 *EndValue	OPTIONAL
	)

Retrieves the 64-bit frequency in Hz and the range of performance counter values.

If StartValue is not NULL, then the value that the performance counter starts with immediately after is it rolls over is returned in StartValue. If EndValue is not NULL, then the value that the performance counter end with immediately before it rolls over is returned in EndValue. The 64-bit frequency of the performance counter in Hz is always returned. If StartValue is less than EndValue, then the performance counter counts up. If StartValue is greater than EndValue, then the performance counter counts down. For example, a 64-bit free running counter that counts up would have a StartValue of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.

Parameters

StartValue	The value the performance counter starts with when it rolls over.
EndValue	The value that the performance counter ends with before it rolls over.

Returns

The frequency in Hz.

Definition at line 222 of file CpuTimerLib.c.

GetTimeInNanoSecond()

UINT64 EFIAPI GetTimeInNanoSecond

(

IN UINT64

Ticks

)

Converts elapsed ticks of performance counter to time in nanoseconds.

This function converts the elapsed ticks of running performance counter to time value in unit of nanoseconds.

Parameters

Ticks

The number of elapsed ticks of running performance counter.

Returns

The elapsed time in nanoseconds.

Definition at line 251 of file CpuTimerLib.c.

InternalCpuDelay()

VOID InternalCpuDelay

(

IN UINT64

Delay

)

Stalls the CPU for at least the given number of ticks.

Stalls the CPU for at least the given number of ticks. It's invoked by MicroSecondDelay() and NanoSecondDelay().

Parameters

Delay

A period of time to delay in ticks.

Definition at line 96 of file CpuTimerLib.c.

InternalGetPerformanceCounterFrequency()

UINT64 InternalGetPerformanceCounterFrequency

(

VOID

)

Internal function to retrieves the 64-bit frequency in Hz.

Internal function to retrieves the 64-bit frequency in Hz.

Returns

The frequency in Hz.

Definition at line 42 of file BaseAcpiTimerLib.c.

MicroSecondDelay()

UINTN EFIAPI MicroSecondDelay

(

IN UINTN

MicroSeconds

)

Stalls the CPU for at least the given number of microseconds.

Stalls the CPU for the number of microseconds specified by MicroSeconds.

Parameters

[in]

MicroSeconds

The minimum number of microseconds to delay.

Returns

MicroSeconds

Definition at line 130 of file CpuTimerLib.c.

NanoSecondDelay()

UINTN EFIAPI NanoSecondDelay

(

IN UINTN

NanoSeconds

)

Stalls the CPU for at least the given number of nanoseconds.

Stalls the CPU for the number of nanoseconds specified by NanoSeconds.

Parameters

NanoSeconds

The minimum number of nanoseconds to delay.

Returns

NanoSeconds

Definition at line 159 of file CpuTimerLib.c.

Variable Documentation

mCpuCrystalFrequencyHobGuid

GUID mCpuCrystalFrequencyHobGuid

Initial value:

= {
  0xe1ec5ad0, 0x8569, 0x46bd, { 0x8d, 0xcd, 0x3b, 0x9f, 0x6f, 0x45, 0x82, 0x7a }
}

Definition at line 16 of file CpuTimerLib.c.