EDK2 doxygen online documents - Firmware Encoding Index 1
EDK2 doxygen online documents - Firmware Encoding Index
Functions

MdePkg/Include/Library/TimerLib.h File Reference

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Functions

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)

Detailed Description

Provides calibrated delay and performance counter services.

Copyright (c) 2006 - 2011, 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 TimerLib.h.


Function Documentation

UINT64 EFIAPI GetPerformanceCounter ( VOID  )

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.

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.

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.

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.

Retrieves the current value of the 64-bit free running Time-Stamp counter.

The time-stamp counter (as implemented in the P6 family, Pentium, Pentium M, Pentium 4, Intel Xeon, Intel Core Solo and Intel Core Duo processors and later processors) is a 64-bit counter that is set to 0 following a RESET of the processor. Following a RESET, the counter increments even when the processor is halted by the HLT instruction or the external STPCLK# pin. Note that the assertion of the external DPSLP# pin may cause the time-stamp counter to stop.

The properties of the counter can be retrieved by the GetPerformanceCounterProperties() function.

Returns:
The current value of the free running performance counter.

Definition at line 142 of file ArmArchTimerLib.c.

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:
StartValueThe value the performance counter starts with when it rolls over.
EndValueThe value that the performance counter ends with before it rolls over.
Returns:
The frequency in Hz.

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, 0x0, is returned in StartValue. If EndValue is not NULL, then the value that the performance counter end with, 0xFFFFFFFFFFFFFFFF, is returned in EndValue.

The 64-bit frequency of the performance counter, in Hz, is always returned. To determine average processor clock frequency, Intel recommends the use of EMON logic to count processor core clocks over the period of time for which the average is required.

Parameters:
[out]StartValuePointer to where the performance counter's starting value is saved, or NULL.
[out]EndValuePointer to where the performance counter's ending value is saved, or NULL.
Returns:
The frequency in Hz.

Definition at line 175 of file ArmArchTimerLib.c.

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:
TicksThe number of elapsed ticks of running performance counter.
Returns:
The elapsed time in nanoseconds.

Definition at line 260 of file X86TimerLib.c.

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:
MicroSecondsThe minimum number of microseconds to delay.
Returns:
The value of MicroSeconds inputted.

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

Parameters:
MicroSecondsThe minimum number of microseconds to delay.
Returns:
The value of MicroSeconds inputted.

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

Stalls the CPU for the number of microseconds specified by MicroSeconds. The hardware timer is 32 bits. The maximum possible delay is (0xFFFFFFFF / TimerFrequencyMHz), i.e. ([32bits] / FreqInMHz) For example: +----------------+------------+----------+----------+ | TimerFrequency | MaxDelay | MaxDelay | MaxDelay | | (MHz) | (us) | (s) | (min) | +----------------+------------+----------+----------+ | 1 | 0xFFFFFFFF | 4294 | 71.5 | | 5 | 0x33333333 | 859 | 14.3 | | 10 | 0x19999999 | 429 | 7.2 | | 50 | 0x051EB851 | 86 | 1.4 | +----------------+------------+----------+----------+ If it becomes necessary to support higher delays, then consider using the real time clock.

During this delay, the cpu is not yielded to any other process, with one exception: events that are triggered off a timer and which execute at a higher TPL than this function. These events may call MicroSecondDelay (or NanoSecondDelay) to fulfil their own needs. Therefore, this function must be re-entrant, as it may be interrupted and re-started.

Parameters:
MicroSecondsThe minimum number of microseconds to delay.
Returns:
The value of MicroSeconds inputted.

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

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

Parameters:
MicroSecondsThe minimum number of microseconds to delay.
Returns:
MicroSeconds

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

This function wraps EsalStall function of Extended SAL Stall Services Class. It stalls the CPU for the number of microseconds specified by MicroSeconds.

Parameters:
MicroSecondsThe minimum number of microseconds to delay.
Returns:
MicroSeconds

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

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

Parameters:
MicroSecondsThe minimum number of microseconds to delay.
Returns:
MicroSeconds

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

Parameters:
MicroSecondsThe minimum number of microseconds to delay.
Returns:
The value of MicroSeconds inputted.

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

Stalls the CPU for the number of microseconds specified by MicroSeconds. The hardware timer is 32 bits. The maximum possible delay is (0xFFFFFFFF / TimerFrequencyMHz), i.e. ([32bits] / FreqInMHz) For example: +----------------+------------+----------+----------+ | TimerFrequency | MaxDelay | MaxDelay | MaxDelay | | (MHz) | (us) | (s) | (min) | +----------------+------------+----------+----------+ | 1 | 0xFFFFFFFF | 4294 | 71.5 | | 5 | 0x33333333 | 859 | 14.3 | | 10 | 0x19999999 | 429 | 7.2 | | 50 | 0x051EB851 | 86 | 1.4 | +----------------+------------+----------+----------+ If it becomes necessary to support higher delays, then consider using the real time clock.

During this delay, the cpu is not yielded to any other process, with one exception: events that are triggered off a timer and which execute at a higher TPL than this function. These events may call MicroSecondDelay (or NanoSecondDelay) to fulfil their own needs. Therefore, this function must be re-entrant, as it may be interrupted and re-started.

Parameters:
MicroSecondsThe minimum number of microseconds to delay.
Returns:
The value of MicroSeconds inputted.

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

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

Parameters:
MicroSecondsThe minimum number of microseconds to delay.
Returns:
The value of MicroSeconds inputted.

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

This function wraps EsalStall function of Extended SAL Stall Services Class. It stalls the CPU for the number of microseconds specified by MicroSeconds.

Parameters:
MicroSecondsThe minimum number of microseconds to delay.
Returns:
MicroSeconds

Stalls the CPU for at least the specified number of MicroSeconds.

Parameters:
[in]MicroSecondsThe minimum number of microseconds to delay.
Returns:
The value of MicroSeconds input.

Definition at line 75 of file ArmArchTimerLib.c.

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:
NanoSecondsThe minimum number of nanoseconds to delay.
Returns:
The value of NanoSeconds inputted.

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

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

When the timer frequency is 1MHz, each tick corresponds to 1 microsecond. Therefore, the nanosecond delay will be rounded up to the nearest 1 microsecond.

Parameters:
NanoSecondsThe minimum number of nanoseconds to delay.
Returns:
The value of NanoSeconds inputted.

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

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

Parameters:
NanoSecondsThe minimum number of nanoseconds to delay.
Returns:
NanoSeconds

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

This function wraps EsalStall function of Extended SAL Stall Services Class. It stalls the CPU for the number of nanoseconds specified by NanoSeconds.

Parameters:
NanoSecondsThe minimum number of nanoseconds to delay.
Returns:
NanoSeconds

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

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

Parameters:
NanoSecondsThe minimum number of nanoseconds to delay.
Returns:
NanoSeconds

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

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

When the timer frequency is 1MHz, each tick corresponds to 1 microsecond. Therefore, the nanosecond delay will be rounded up to the nearest 1 microsecond.

Parameters:
NanoSecondsThe minimum number of nanoseconds to delay.
Returns:
The value of NanoSeconds inputted.

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

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

Parameters:
NanoSecondsThe minimum number of nanoseconds to delay.
Returns:
The value of NanoSeconds inputted.

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

This function wraps EsalStall function of Extended SAL Stall Services Class. It stalls the CPU for the number of nanoseconds specified by NanoSeconds.

Parameters:
NanoSecondsThe minimum number of nanoseconds to delay.
Returns:
NanoSeconds

Stalls the CPU for at least the specified number of NanoSeconds.

Parameters:
[in]NanoSecondsThe minimum number of nanoseconds to delay.
Returns:
The value of NanoSeconds input.

Definition at line 114 of file ArmArchTimerLib.c.

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