EdkCompatibilityPkg/Foundation/Library/EdkIIGlueLib/Include/Library/EdkIIGlueTimerLib.h

   1 /*++
   2
   3 Copyright (c) 2004 - 2006, Intel Corporation
   4 All rights reserved. This program and the accompanying materials
   5 are licensed and made available under the terms and conditions of the BSD License
   6 which accompanies this distribution.  The full text of the license may be found at
   7 http://opensource.org/licenses/bsd-license.php
   8
   9 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11
  12
  13 Module Name:
  14
  15   EdkIIGlueTimerLib.h
  16
  17 Abstract:
  18
  19   Public header file for Timer Lib
  20
  21 --*/
  22
  23 #ifndef __EDKII_GLUE_TIMER_LIB_H__
  24 #define __EDKII_GLUE_TIMER_LIB_H__
  25
  26 /**
  27   Stalls the CPU for at least the given number of microseconds.
  28
  29   Stalls the CPU for the number of microseconds specified by MicroSeconds.
  30
  31   @param  MicroSeconds  The minimum number of microseconds to delay.
  32
  33   @return MicroSeconds
  34
  35 **/
  36 UINTN
  37 EFIAPI
  38 MicroSecondDelay (
  39   IN      UINTN                     MicroSeconds
  40   );
  41
  42 /**
  43   Stalls the CPU for at least the given number of nanoseconds.
  44
  45   Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
  46
  47   @param  NanoSeconds The minimum number of nanoseconds to delay.
  48
  49   @return NanoSeconds
  50
  51 **/
  52 UINTN
  53 EFIAPI
  54 NanoSecondDelay (
  55   IN      UINTN                     NanoSeconds
  56   );
  57
  58 /**
  59   Retrieves the current value of a 64-bit free running performance counter.
  60
  61   Retrieves the current value of a 64-bit free running performance counter. The
  62   counter can either count up by 1 or count down by 1. If the physical
  63   performance counter counts by a larger increment, then the counter values
  64   must be translated. The properties of the counter can be retrieved from
  65   GetPerformanceCounterProperties().
  66
  67   @return The current value of the free running performance counter.
  68
  69 **/
  70 UINT64
  71 EFIAPI
  72 GetPerformanceCounter (
  73   VOID
  74   );
  75
  76 /**
  77   Retrieves the 64-bit frequency in Hz and the range of performance counter
  78   values.
  79
  80   If StartValue is not NULL, then the value that the performance counter starts
  81   with immediately after is it rolls over is returned in StartValue. If
  82   EndValue is not NULL, then the value that the performance counter end with
  83   immediately before it rolls over is returned in EndValue. The 64-bit
  84   frequency of the performance counter in Hz is always returned. If StartValue
  85   is less than EndValue, then the performance counter counts up. If StartValue
  86   is greater than EndValue, then the performance counter counts down. For
  87   example, a 64-bit free running counter that counts up would have a StartValue
  88   of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
  89   that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
  90
  91   @param  StartValue  The value the performance counter starts with when it
  92                       rolls over.
  93   @param  EndValue    The value that the performance counter ends with before
  94                       it rolls over.
  95
  96   @return The frequency in Hz.
  97
  98 **/
  99 UINT64
 100 EFIAPI
 101 GetPerformanceCounterProperties (
 102   OUT      UINT64                    *StartValue,  OPTIONAL
 103   OUT      UINT64                    *EndValue     OPTIONAL
 104   );
 105
 106 #endif