1 /*++ 2 3 Copyright (c) 2004 - 2006, Intel Corporation. All rights reserved.<BR> 4 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 107