1 /****************************************************************************** 2 * 3 * Name: hwtimer.c - ACPI Power Management Timer Interface 4 * 5 *****************************************************************************/ 6 7 /* 8 * Copyright (C) 2000 - 2016, Intel Corp. 9 * All rights reserved. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions, and the following disclaimer, 16 * without modification. 17 * 2. Redistributions in binary form must reproduce at minimum a disclaimer 18 * substantially similar to the "NO WARRANTY" disclaimer below 19 * ("Disclaimer") and any redistribution must be conditioned upon 20 * including a substantially similar Disclaimer requirement for further 21 * binary redistribution. 22 * 3. Neither the names of the above-listed copyright holders nor the names 23 * of any contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * Alternatively, this software may be distributed under the terms of the 27 * GNU General Public License ("GPL") version 2 as published by the Free 28 * Software Foundation. 29 * 30 * NO WARRANTY 31 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 32 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 33 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR 34 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 35 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 36 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 37 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 40 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 41 * POSSIBILITY OF SUCH DAMAGES. 42 */ 43 44 #define EXPORT_ACPI_INTERFACES 45 46 #include "acpi.h" 47 #include "accommon.h" 48 49 #define _COMPONENT ACPI_HARDWARE 50 ACPI_MODULE_NAME ("hwtimer") 51 52 53 #if (!ACPI_REDUCED_HARDWARE) /* Entire module */ 54 /****************************************************************************** 55 * 56 * FUNCTION: AcpiGetTimerResolution 57 * 58 * PARAMETERS: Resolution - Where the resolution is returned 59 * 60 * RETURN: Status and timer resolution 61 * 62 * DESCRIPTION: Obtains resolution of the ACPI PM Timer (24 or 32 bits). 63 * 64 ******************************************************************************/ 65 66 ACPI_STATUS 67 AcpiGetTimerResolution ( 68 UINT32 *Resolution) 69 { 70 ACPI_FUNCTION_TRACE (AcpiGetTimerResolution); 71 72 73 if (!Resolution) 74 { 75 return_ACPI_STATUS (AE_BAD_PARAMETER); 76 } 77 78 if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) == 0) 79 { 80 *Resolution = 24; 81 } 82 else 83 { 84 *Resolution = 32; 85 } 86 87 return_ACPI_STATUS (AE_OK); 88 } 89 90 ACPI_EXPORT_SYMBOL (AcpiGetTimerResolution) 91 92 93 /****************************************************************************** 94 * 95 * FUNCTION: AcpiGetTimer 96 * 97 * PARAMETERS: Ticks - Where the timer value is returned 98 * 99 * RETURN: Status and current timer value (ticks) 100 * 101 * DESCRIPTION: Obtains current value of ACPI PM Timer (in ticks). 102 * 103 ******************************************************************************/ 104 105 ACPI_STATUS 106 AcpiGetTimer ( 107 UINT32 *Ticks) 108 { 109 ACPI_STATUS Status; 110 111 112 ACPI_FUNCTION_TRACE (AcpiGetTimer); 113 114 115 if (!Ticks) 116 { 117 return_ACPI_STATUS (AE_BAD_PARAMETER); 118 } 119 120 /* ACPI 5.0A: PM Timer is optional */ 121 122 if (!AcpiGbl_FADT.XPmTimerBlock.Address) 123 { 124 return_ACPI_STATUS (AE_SUPPORT); 125 } 126 127 Status = AcpiHwRead (Ticks, &AcpiGbl_FADT.XPmTimerBlock); 128 return_ACPI_STATUS (Status); 129 } 130 131 ACPI_EXPORT_SYMBOL (AcpiGetTimer) 132 133 134 /****************************************************************************** 135 * 136 * FUNCTION: AcpiGetTimerDuration 137 * 138 * PARAMETERS: StartTicks - Starting timestamp 139 * EndTicks - End timestamp 140 * TimeElapsed - Where the elapsed time is returned 141 * 142 * RETURN: Status and TimeElapsed 143 * 144 * DESCRIPTION: Computes the time elapsed (in microseconds) between two 145 * PM Timer time stamps, taking into account the possibility of 146 * rollovers, the timer resolution, and timer frequency. 147 * 148 * The PM Timer's clock ticks at roughly 3.6 times per 149 * _microsecond_, and its clock continues through Cx state 150 * transitions (unlike many CPU timestamp counters) -- making it 151 * a versatile and accurate timer. 152 * 153 * Note that this function accommodates only a single timer 154 * rollover. Thus for 24-bit timers, this function should only 155 * be used for calculating durations less than ~4.6 seconds 156 * (~20 minutes for 32-bit timers) -- calculations below: 157 * 158 * 2**24 Ticks / 3,600,000 Ticks/Sec = 4.66 sec 159 * 2**32 Ticks / 3,600,000 Ticks/Sec = 1193 sec or 19.88 minutes 160 * 161 ******************************************************************************/ 162 163 ACPI_STATUS 164 AcpiGetTimerDuration ( 165 UINT32 StartTicks, 166 UINT32 EndTicks, 167 UINT32 *TimeElapsed) 168 { 169 ACPI_STATUS Status; 170 UINT32 DeltaTicks; 171 UINT64 Quotient; 172 173 174 ACPI_FUNCTION_TRACE (AcpiGetTimerDuration); 175 176 177 if (!TimeElapsed) 178 { 179 return_ACPI_STATUS (AE_BAD_PARAMETER); 180 } 181 182 /* ACPI 5.0A: PM Timer is optional */ 183 184 if (!AcpiGbl_FADT.XPmTimerBlock.Address) 185 { 186 return_ACPI_STATUS (AE_SUPPORT); 187 } 188 189 /* 190 * Compute Tick Delta: 191 * Handle (max one) timer rollovers on 24-bit versus 32-bit timers. 192 */ 193 if (StartTicks < EndTicks) 194 { 195 DeltaTicks = EndTicks - StartTicks; 196 } 197 else if (StartTicks > EndTicks) 198 { 199 if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) == 0) 200 { 201 /* 24-bit Timer */ 202 203 DeltaTicks = (((0x00FFFFFF - StartTicks) + EndTicks) & 0x00FFFFFF); 204 } 205 else 206 { 207 /* 32-bit Timer */ 208 209 DeltaTicks = (0xFFFFFFFF - StartTicks) + EndTicks; 210 } 211 } 212 else /* StartTicks == EndTicks */ 213 { 214 *TimeElapsed = 0; 215 return_ACPI_STATUS (AE_OK); 216 } 217 218 /* 219 * Compute Duration (Requires a 64-bit multiply and divide): 220 * 221 * TimeElapsed (microseconds) = 222 * (DeltaTicks * ACPI_USEC_PER_SEC) / ACPI_PM_TIMER_FREQUENCY; 223 */ 224 Status = AcpiUtShortDivide (((UINT64) DeltaTicks) * ACPI_USEC_PER_SEC, 225 ACPI_PM_TIMER_FREQUENCY, &Quotient, NULL); 226 227 *TimeElapsed = (UINT32) Quotient; 228 return_ACPI_STATUS (Status); 229 } 230 231 ACPI_EXPORT_SYMBOL (AcpiGetTimerDuration) 232 233 #endif /* !ACPI_REDUCED_HARDWARE */ 234