1 /****************************************************************************** 2 * 3 * Name: hwtimer.c - ACPI Power Management Timer Interface 4 * 5 *****************************************************************************/ 6 7 /* 8 * Copyright (C) 2000 - 2012, 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 #include <contrib/dev/acpica/include/acpi.h> 45 #include <contrib/dev/acpica/include/accommon.h> 46 47 #define _COMPONENT ACPI_HARDWARE 48 ACPI_MODULE_NAME ("hwtimer") 49 50 51 #if (!ACPI_REDUCED_HARDWARE) /* Entire module */ 52 /****************************************************************************** 53 * 54 * FUNCTION: AcpiGetTimerResolution 55 * 56 * PARAMETERS: Resolution - Where the resolution is returned 57 * 58 * RETURN: Status and timer resolution 59 * 60 * DESCRIPTION: Obtains resolution of the ACPI PM Timer (24 or 32 bits). 61 * 62 ******************************************************************************/ 63 64 ACPI_STATUS 65 AcpiGetTimerResolution ( 66 UINT32 *Resolution) 67 { 68 ACPI_FUNCTION_TRACE (AcpiGetTimerResolution); 69 70 71 if (!Resolution) 72 { 73 return_ACPI_STATUS (AE_BAD_PARAMETER); 74 } 75 76 if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) == 0) 77 { 78 *Resolution = 24; 79 } 80 else 81 { 82 *Resolution = 32; 83 } 84 85 return_ACPI_STATUS (AE_OK); 86 } 87 88 ACPI_EXPORT_SYMBOL (AcpiGetTimerResolution) 89 90 91 /****************************************************************************** 92 * 93 * FUNCTION: AcpiGetTimer 94 * 95 * PARAMETERS: Ticks - Where the timer value is returned 96 * 97 * RETURN: Status and current timer value (ticks) 98 * 99 * DESCRIPTION: Obtains current value of ACPI PM Timer (in ticks). 100 * 101 ******************************************************************************/ 102 103 ACPI_STATUS 104 AcpiGetTimer ( 105 UINT32 *Ticks) 106 { 107 ACPI_STATUS Status; 108 109 110 ACPI_FUNCTION_TRACE (AcpiGetTimer); 111 112 113 if (!Ticks) 114 { 115 return_ACPI_STATUS (AE_BAD_PARAMETER); 116 } 117 118 Status = AcpiHwRead (Ticks, &AcpiGbl_FADT.XPmTimerBlock); 119 120 return_ACPI_STATUS (Status); 121 } 122 123 ACPI_EXPORT_SYMBOL (AcpiGetTimer) 124 125 126 /****************************************************************************** 127 * 128 * FUNCTION: AcpiGetTimerDuration 129 * 130 * PARAMETERS: StartTicks - Starting timestamp 131 * EndTicks - End timestamp 132 * TimeElapsed - Where the elapsed time is returned 133 * 134 * RETURN: Status and TimeElapsed 135 * 136 * DESCRIPTION: Computes the time elapsed (in microseconds) between two 137 * PM Timer time stamps, taking into account the possibility of 138 * rollovers, the timer resolution, and timer frequency. 139 * 140 * The PM Timer's clock ticks at roughly 3.6 times per 141 * _microsecond_, and its clock continues through Cx state 142 * transitions (unlike many CPU timestamp counters) -- making it 143 * a versatile and accurate timer. 144 * 145 * Note that this function accommodates only a single timer 146 * rollover. Thus for 24-bit timers, this function should only 147 * be used for calculating durations less than ~4.6 seconds 148 * (~20 minutes for 32-bit timers) -- calculations below: 149 * 150 * 2**24 Ticks / 3,600,000 Ticks/Sec = 4.66 sec 151 * 2**32 Ticks / 3,600,000 Ticks/Sec = 1193 sec or 19.88 minutes 152 * 153 ******************************************************************************/ 154 155 ACPI_STATUS 156 AcpiGetTimerDuration ( 157 UINT32 StartTicks, 158 UINT32 EndTicks, 159 UINT32 *TimeElapsed) 160 { 161 ACPI_STATUS Status; 162 UINT32 DeltaTicks; 163 UINT64 Quotient; 164 165 166 ACPI_FUNCTION_TRACE (AcpiGetTimerDuration); 167 168 169 if (!TimeElapsed) 170 { 171 return_ACPI_STATUS (AE_BAD_PARAMETER); 172 } 173 174 /* 175 * Compute Tick Delta: 176 * Handle (max one) timer rollovers on 24-bit versus 32-bit timers. 177 */ 178 if (StartTicks < EndTicks) 179 { 180 DeltaTicks = EndTicks - StartTicks; 181 } 182 else if (StartTicks > EndTicks) 183 { 184 if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) == 0) 185 { 186 /* 24-bit Timer */ 187 188 DeltaTicks = (((0x00FFFFFF - StartTicks) + EndTicks) & 0x00FFFFFF); 189 } 190 else 191 { 192 /* 32-bit Timer */ 193 194 DeltaTicks = (0xFFFFFFFF - StartTicks) + EndTicks; 195 } 196 } 197 else /* StartTicks == EndTicks */ 198 { 199 *TimeElapsed = 0; 200 return_ACPI_STATUS (AE_OK); 201 } 202 203 /* 204 * Compute Duration (Requires a 64-bit multiply and divide): 205 * 206 * TimeElapsed = (DeltaTicks * 1000000) / PM_TIMER_FREQUENCY; 207 */ 208 Status = AcpiUtShortDivide (((UINT64) DeltaTicks) * 1000000, 209 PM_TIMER_FREQUENCY, &Quotient, NULL); 210 211 *TimeElapsed = (UINT32) Quotient; 212 return_ACPI_STATUS (Status); 213 } 214 215 ACPI_EXPORT_SYMBOL (AcpiGetTimerDuration) 216 217 #endif /* !ACPI_REDUCED_HARDWARE */ 218