1 /** @file 2 Timer Library functions built upon ITC on IPF. 3 4 Copyright (c) 2006 - 2011, Intel Corporation. All rights reserved.<BR> 5 This program and the accompanying materials 6 are licensed and made available under the terms and conditions of the BSD License 7 which accompanies this distribution. The full text of the license may be found at 8 http://opensource.org/licenses/bsd-license.php. 9 10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 12 13 **/ 14 15 #include <Base.h> 16 #include <Library/TimerLib.h> 17 #include <Library/BaseLib.h> 18 #include <Library/PalLib.h> 19 20 21 /** 22 Performs a delay measured as number of ticks. 23 24 An internal function to perform a delay measured as number of ticks. It's 25 invoked by MicroSecondDelay() and NanoSecondDelay(). 26 27 @param Delay The number of ticks to delay. 28 29 **/ 30 VOID 31 EFIAPI 32 InternalIpfDelay ( 33 IN INT64 Delay 34 ) 35 { 36 INT64 Ticks; 37 38 // 39 // The target timer count is calculated here 40 // 41 Ticks = (INT64)AsmReadItc () + Delay; 42 43 // 44 // Wait until time out 45 // Delay > 2^63 could not be handled by this function 46 // Timer wrap-arounds are handled correctly by this function 47 // 48 while (Ticks - (INT64)AsmReadItc() >= 0); 49 } 50 51 /** 52 Stalls the CPU for at least the given number of microseconds. 53 54 Stalls the CPU for the number of microseconds specified by MicroSeconds. 55 56 @param MicroSeconds The minimum number of microseconds to delay. 57 58 @return The value of MicroSeconds inputted. 59 60 **/ 61 UINTN 62 EFIAPI 63 MicroSecondDelay ( 64 IN UINTN MicroSeconds 65 ) 66 { 67 InternalIpfDelay ( 68 GetPerformanceCounterProperties (NULL, NULL) * 69 MicroSeconds / 70 1000000 71 ); 72 return MicroSeconds; 73 } 74 75 /** 76 Stalls the CPU for at least the given number of nanoseconds. 77 78 Stalls the CPU for the number of nanoseconds specified by NanoSeconds. 79 80 @param NanoSeconds The minimum number of nanoseconds to delay. 81 82 @return The value of NanoSeconds inputted. 83 84 **/ 85 UINTN 86 EFIAPI 87 NanoSecondDelay ( 88 IN UINTN NanoSeconds 89 ) 90 { 91 InternalIpfDelay ( 92 GetPerformanceCounterProperties (NULL, NULL) * 93 NanoSeconds / 94 1000000000 95 ); 96 return NanoSeconds; 97 } 98 99 /** 100 Retrieves the current value of a 64-bit free running performance counter. 101 102 The counter can either count up by 1 or count down by 1. If the physical 103 performance counter counts by a larger increment, then the counter values 104 must be translated. The properties of the counter can be retrieved from 105 GetPerformanceCounterProperties(). 106 107 @return The current value of the free running performance counter. 108 109 **/ 110 UINT64 111 EFIAPI 112 GetPerformanceCounter ( 113 VOID 114 ) 115 { 116 return AsmReadItc (); 117 } 118 119 /** 120 Retrieves the 64-bit frequency in Hz and the range of performance counter 121 values. 122 123 If StartValue is not NULL, then the value that the performance counter starts 124 with immediately after is it rolls over is returned in StartValue. If 125 EndValue is not NULL, then the value that the performance counter end with 126 immediately before it rolls over is returned in EndValue. The 64-bit 127 frequency of the performance counter in Hz is always returned. If StartValue 128 is less than EndValue, then the performance counter counts up. If StartValue 129 is greater than EndValue, then the performance counter counts down. For 130 example, a 64-bit free running counter that counts up would have a StartValue 131 of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter 132 that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0. 133 134 @param StartValue The value the performance counter starts with when it 135 rolls over. 136 @param EndValue The value that the performance counter ends with before 137 it rolls over. 138 139 @return The frequency in Hz. 140 141 **/ 142 UINT64 143 EFIAPI 144 GetPerformanceCounterProperties ( 145 OUT UINT64 *StartValue, OPTIONAL 146 OUT UINT64 *EndValue OPTIONAL 147 ) 148 { 149 PAL_CALL_RETURN PalRet; 150 UINT64 BaseFrequence; 151 152 if (StartValue != NULL) { 153 *StartValue = 0; 154 } 155 156 if (EndValue != NULL) { 157 *EndValue = (UINT64)(-1); 158 } 159 160 PalRet = PalCall (PAL_FREQ_BASE, 0, 0, 0); 161 if (PalRet.Status != 0) { 162 return 1000000; 163 } 164 BaseFrequence = PalRet.r9; 165 166 PalRet = PalCall (PAL_FREQ_RATIOS, 0, 0, 0); 167 if (PalRet.Status != 0) { 168 return 1000000; 169 } 170 171 return BaseFrequence * (PalRet.r11 >> 32) / (UINT32)PalRet.r11; 172 } 173 174 /** 175 Converts elapsed ticks of performance counter to time in nanoseconds. 176 177 This function converts the elapsed ticks of running performance counter to 178 time value in unit of nanoseconds. 179 180 @param Ticks The number of elapsed ticks of running performance counter. 181 182 @return The elapsed time in nanoseconds. 183 184 **/ 185 UINT64 186 EFIAPI 187 GetTimeInNanoSecond ( 188 IN UINT64 Ticks 189 ) 190 { 191 UINT64 Frequency; 192 UINT64 NanoSeconds; 193 UINT64 Remainder; 194 INTN Shift; 195 196 Frequency = GetPerformanceCounterProperties (NULL, NULL); 197 198 // 199 // Ticks 200 // Time = --------- x 1,000,000,000 201 // Frequency 202 // 203 NanoSeconds = MultU64x32 (DivU64x64Remainder (Ticks, Frequency, &Remainder), 1000000000u); 204 205 // 206 // Ensure (Remainder * 1,000,000,000) will not overflow 64-bit. 207 // Since 2^29 < 1,000,000,000 = 0x3B9ACA00 < 2^30, Remainder should < 2^(64-30) = 2^34, 208 // i.e. highest bit set in Remainder should <= 33. 209 // 210 Shift = MAX (0, HighBitSet64 (Remainder) - 33); 211 Remainder = RShiftU64 (Remainder, (UINTN) Shift); 212 Frequency = RShiftU64 (Frequency, (UINTN) Shift); 213 NanoSeconds += DivU64x64Remainder (MultU64x32 (Remainder, 1000000000u), Frequency, NULL); 214 215 return NanoSeconds; 216 } 217
