1 /****************************************************************************** 2 * 3 * Name: hwtimer.c - ACPI Power Management Timer Interface 4 * 5 *****************************************************************************/ 6 7 /* 8 * Copyright (C) 2000 - 2018, 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/acpi.h> 47 #include "accommon.h" 48 49 #define _COMPONENT ACPI_HARDWARE 50 ACPI_MODULE_NAME("hwtimer") 51 52 #if (!ACPI_REDUCED_HARDWARE) /* Entire module */ 53 /****************************************************************************** 54 * 55 * FUNCTION: acpi_get_timer_resolution 56 * 57 * PARAMETERS: resolution - Where the resolution is returned 58 * 59 * RETURN: Status and timer resolution 60 * 61 * DESCRIPTION: Obtains resolution of the ACPI PM Timer (24 or 32 bits). 62 * 63 ******************************************************************************/ 64 acpi_status acpi_get_timer_resolution(u32 * resolution) 65 { 66 ACPI_FUNCTION_TRACE(acpi_get_timer_resolution); 67 68 if (!resolution) { 69 return_ACPI_STATUS(AE_BAD_PARAMETER); 70 } 71 72 if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) { 73 *resolution = 24; 74 } else { 75 *resolution = 32; 76 } 77 78 return_ACPI_STATUS(AE_OK); 79 } 80 81 ACPI_EXPORT_SYMBOL(acpi_get_timer_resolution) 82 83 /****************************************************************************** 84 * 85 * FUNCTION: acpi_get_timer 86 * 87 * PARAMETERS: ticks - Where the timer value is returned 88 * 89 * RETURN: Status and current timer value (ticks) 90 * 91 * DESCRIPTION: Obtains current value of ACPI PM Timer (in ticks). 92 * 93 ******************************************************************************/ 94 acpi_status acpi_get_timer(u32 * ticks) 95 { 96 acpi_status status; 97 u64 timer_value; 98 99 ACPI_FUNCTION_TRACE(acpi_get_timer); 100 101 if (!ticks) { 102 return_ACPI_STATUS(AE_BAD_PARAMETER); 103 } 104 105 /* ACPI 5.0A: PM Timer is optional */ 106 107 if (!acpi_gbl_FADT.xpm_timer_block.address) { 108 return_ACPI_STATUS(AE_SUPPORT); 109 } 110 111 status = acpi_hw_read(&timer_value, &acpi_gbl_FADT.xpm_timer_block); 112 if (ACPI_SUCCESS(status)) { 113 114 /* ACPI PM Timer is defined to be 32 bits (PM_TMR_LEN) */ 115 116 *ticks = (u32)timer_value; 117 } 118 119 return_ACPI_STATUS(status); 120 } 121 122 ACPI_EXPORT_SYMBOL(acpi_get_timer) 123 124 /****************************************************************************** 125 * 126 * FUNCTION: acpi_get_timer_duration 127 * 128 * PARAMETERS: start_ticks - Starting timestamp 129 * end_ticks - End timestamp 130 * time_elapsed - Where the elapsed time is returned 131 * 132 * RETURN: Status and time_elapsed 133 * 134 * DESCRIPTION: Computes the time elapsed (in microseconds) between two 135 * PM Timer time stamps, taking into account the possibility of 136 * rollovers, the timer resolution, and timer frequency. 137 * 138 * The PM Timer's clock ticks at roughly 3.6 times per 139 * _microsecond_, and its clock continues through Cx state 140 * transitions (unlike many CPU timestamp counters) -- making it 141 * a versatile and accurate timer. 142 * 143 * Note that this function accommodates only a single timer 144 * rollover. Thus for 24-bit timers, this function should only 145 * be used for calculating durations less than ~4.6 seconds 146 * (~20 minutes for 32-bit timers) -- calculations below: 147 * 148 * 2**24 Ticks / 3,600,000 Ticks/Sec = 4.66 sec 149 * 2**32 Ticks / 3,600,000 Ticks/Sec = 1193 sec or 19.88 minutes 150 * 151 ******************************************************************************/ 152 acpi_status 153 acpi_get_timer_duration(u32 start_ticks, u32 end_ticks, u32 *time_elapsed) 154 { 155 acpi_status status; 156 u64 delta_ticks; 157 u64 quotient; 158 159 ACPI_FUNCTION_TRACE(acpi_get_timer_duration); 160 161 if (!time_elapsed) { 162 return_ACPI_STATUS(AE_BAD_PARAMETER); 163 } 164 165 /* ACPI 5.0A: PM Timer is optional */ 166 167 if (!acpi_gbl_FADT.xpm_timer_block.address) { 168 return_ACPI_STATUS(AE_SUPPORT); 169 } 170 171 if (start_ticks == end_ticks) { 172 *time_elapsed = 0; 173 return_ACPI_STATUS(AE_OK); 174 } 175 176 /* 177 * Compute Tick Delta: 178 * Handle (max one) timer rollovers on 24-bit versus 32-bit timers. 179 */ 180 delta_ticks = end_ticks; 181 if (start_ticks > end_ticks) { 182 if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) { 183 184 /* 24-bit Timer */ 185 186 delta_ticks |= (u64)1 << 24; 187 } else { 188 /* 32-bit Timer */ 189 190 delta_ticks |= (u64)1 << 32; 191 } 192 } 193 delta_ticks -= start_ticks; 194 195 /* 196 * Compute Duration (Requires a 64-bit multiply and divide): 197 * 198 * time_elapsed (microseconds) = 199 * (delta_ticks * ACPI_USEC_PER_SEC) / ACPI_PM_TIMER_FREQUENCY; 200 */ 201 status = acpi_ut_short_divide(delta_ticks * ACPI_USEC_PER_SEC, 202 ACPI_PM_TIMER_FREQUENCY, "ient, NULL); 203 204 *time_elapsed = (u32)quotient; 205 return_ACPI_STATUS(status); 206 } 207 208 ACPI_EXPORT_SYMBOL(acpi_get_timer_duration) 209 #endif /* !ACPI_REDUCED_HARDWARE */ 210