hwtimer.c revision 99146
1 2/****************************************************************************** 3 * 4 * Name: hwtimer.c - ACPI Power Management Timer Interface 5 * $Revision: 20 $ 6 * 7 *****************************************************************************/ 8 9/****************************************************************************** 10 * 11 * 1. Copyright Notice 12 * 13 * Some or all of this work - Copyright (c) 1999 - 2002, Intel Corp. 14 * All rights reserved. 15 * 16 * 2. License 17 * 18 * 2.1. This is your license from Intel Corp. under its intellectual property 19 * rights. You may have additional license terms from the party that provided 20 * you this software, covering your right to use that party's intellectual 21 * property rights. 22 * 23 * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a 24 * copy of the source code appearing in this file ("Covered Code") an 25 * irrevocable, perpetual, worldwide license under Intel's copyrights in the 26 * base code distributed originally by Intel ("Original Intel Code") to copy, 27 * make derivatives, distribute, use and display any portion of the Covered 28 * Code in any form, with the right to sublicense such rights; and 29 * 30 * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent 31 * license (with the right to sublicense), under only those claims of Intel 32 * patents that are infringed by the Original Intel Code, to make, use, sell, 33 * offer to sell, and import the Covered Code and derivative works thereof 34 * solely to the minimum extent necessary to exercise the above copyright 35 * license, and in no event shall the patent license extend to any additions 36 * to or modifications of the Original Intel Code. No other license or right 37 * is granted directly or by implication, estoppel or otherwise; 38 * 39 * The above copyright and patent license is granted only if the following 40 * conditions are met: 41 * 42 * 3. Conditions 43 * 44 * 3.1. Redistribution of Source with Rights to Further Distribute Source. 45 * Redistribution of source code of any substantial portion of the Covered 46 * Code or modification with rights to further distribute source must include 47 * the above Copyright Notice, the above License, this list of Conditions, 48 * and the following Disclaimer and Export Compliance provision. In addition, 49 * Licensee must cause all Covered Code to which Licensee contributes to 50 * contain a file documenting the changes Licensee made to create that Covered 51 * Code and the date of any change. Licensee must include in that file the 52 * documentation of any changes made by any predecessor Licensee. Licensee 53 * must include a prominent statement that the modification is derived, 54 * directly or indirectly, from Original Intel Code. 55 * 56 * 3.2. Redistribution of Source with no Rights to Further Distribute Source. 57 * Redistribution of source code of any substantial portion of the Covered 58 * Code or modification without rights to further distribute source must 59 * include the following Disclaimer and Export Compliance provision in the 60 * documentation and/or other materials provided with distribution. In 61 * addition, Licensee may not authorize further sublicense of source of any 62 * portion of the Covered Code, and must include terms to the effect that the 63 * license from Licensee to its licensee is limited to the intellectual 64 * property embodied in the software Licensee provides to its licensee, and 65 * not to intellectual property embodied in modifications its licensee may 66 * make. 67 * 68 * 3.3. Redistribution of Executable. Redistribution in executable form of any 69 * substantial portion of the Covered Code or modification must reproduce the 70 * above Copyright Notice, and the following Disclaimer and Export Compliance 71 * provision in the documentation and/or other materials provided with the 72 * distribution. 73 * 74 * 3.4. Intel retains all right, title, and interest in and to the Original 75 * Intel Code. 76 * 77 * 3.5. Neither the name Intel nor any other trademark owned or controlled by 78 * Intel shall be used in advertising or otherwise to promote the sale, use or 79 * other dealings in products derived from or relating to the Covered Code 80 * without prior written authorization from Intel. 81 * 82 * 4. Disclaimer and Export Compliance 83 * 84 * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED 85 * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE 86 * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE, 87 * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY 88 * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY 89 * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A 90 * PARTICULAR PURPOSE. 91 * 92 * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES 93 * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR 94 * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT, 95 * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY 96 * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL 97 * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS 98 * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY 99 * LIMITED REMEDY. 100 * 101 * 4.3. Licensee shall not export, either directly or indirectly, any of this 102 * software or system incorporating such software without first obtaining any 103 * required license or other approval from the U. S. Department of Commerce or 104 * any other agency or department of the United States Government. In the 105 * event Licensee exports any such software from the United States or 106 * re-exports any such software from a foreign destination, Licensee shall 107 * ensure that the distribution and export/re-export of the software is in 108 * compliance with all laws, regulations, orders, or other restrictions of the 109 * U.S. Export Administration Regulations. Licensee agrees that neither it nor 110 * any of its subsidiaries will export/re-export any technical data, process, 111 * software, or service, directly or indirectly, to any country for which the 112 * United States government or any agency thereof requires an export license, 113 * other governmental approval, or letter of assurance, without first obtaining 114 * such license, approval or letter. 115 * 116 *****************************************************************************/ 117 118#include "acpi.h" 119#include "achware.h" 120 121#define _COMPONENT ACPI_HARDWARE 122 ACPI_MODULE_NAME ("hwtimer") 123 124 125/****************************************************************************** 126 * 127 * FUNCTION: AcpiGetTimerResolution 128 * 129 * PARAMETERS: none 130 * 131 * RETURN: Number of bits of resolution in the PM Timer (24 or 32). 132 * 133 * DESCRIPTION: Obtains resolution of the ACPI PM Timer. 134 * 135 ******************************************************************************/ 136 137ACPI_STATUS 138AcpiGetTimerResolution ( 139 UINT32 *Resolution) 140{ 141 ACPI_FUNCTION_TRACE ("AcpiGetTimerResolution"); 142 143 144 if (!Resolution) 145 { 146 return_ACPI_STATUS (AE_BAD_PARAMETER); 147 } 148 149 if (0 == AcpiGbl_FADT->TmrValExt) 150 { 151 *Resolution = 24; 152 } 153 else 154 { 155 *Resolution = 32; 156 } 157 158 return_ACPI_STATUS (AE_OK); 159} 160 161 162/****************************************************************************** 163 * 164 * FUNCTION: AcpiGetTimer 165 * 166 * PARAMETERS: none 167 * 168 * RETURN: Current value of the ACPI PM Timer (in ticks). 169 * 170 * DESCRIPTION: Obtains current value of ACPI PM Timer. 171 * 172 ******************************************************************************/ 173 174ACPI_STATUS 175AcpiGetTimer ( 176 UINT32 *Ticks) 177{ 178 ACPI_FUNCTION_TRACE ("AcpiGetTimer"); 179 180 181 if (!Ticks) 182 { 183 return_ACPI_STATUS (AE_BAD_PARAMETER); 184 } 185 186 *Ticks = AcpiHwLowLevelRead (32, &AcpiGbl_FADT->XPmTmrBlk, 0); 187 188 return_ACPI_STATUS (AE_OK); 189} 190 191 192/****************************************************************************** 193 * 194 * FUNCTION: AcpiGetTimerDuration 195 * 196 * PARAMETERS: StartTicks 197 * EndTicks 198 * TimeElapsed 199 * 200 * RETURN: TimeElapsed 201 * 202 * DESCRIPTION: Computes the time elapsed (in microseconds) between two 203 * PM Timer time stamps, taking into account the possibility of 204 * rollovers, the timer resolution, and timer frequency. 205 * 206 * The PM Timer's clock ticks at roughly 3.6 times per 207 * _microsecond_, and its clock continues through Cx state 208 * transitions (unlike many CPU timestamp counters) -- making it 209 * a versatile and accurate timer. 210 * 211 * Note that this function accomodates only a single timer 212 * rollover. Thus for 24-bit timers, this function should only 213 * be used for calculating durations less than ~4.6 seconds 214 * (~20 hours for 32-bit timers). 215 * 216 ******************************************************************************/ 217 218ACPI_STATUS 219AcpiGetTimerDuration ( 220 UINT32 StartTicks, 221 UINT32 EndTicks, 222 UINT32 *TimeElapsed) 223{ 224 UINT32 DeltaTicks = 0; 225 UINT64_OVERLAY NormalizedTicks; 226 ACPI_STATUS Status; 227 ACPI_INTEGER OutQuotient; 228 229 230 ACPI_FUNCTION_TRACE ("AcpiGetTimerDuration"); 231 232 233 if (!TimeElapsed) 234 { 235 return_ACPI_STATUS (AE_BAD_PARAMETER); 236 } 237 238 /* 239 * Compute Tick Delta: 240 * ------------------- 241 * Handle (max one) timer rollovers on 24- versus 32-bit timers. 242 */ 243 if (StartTicks < EndTicks) 244 { 245 DeltaTicks = EndTicks - StartTicks; 246 } 247 else if (StartTicks > EndTicks) 248 { 249 if (0 == AcpiGbl_FADT->TmrValExt) 250 { 251 /* 24-bit Timer */ 252 253 DeltaTicks = (((0x00FFFFFF - StartTicks) + EndTicks) & 0x00FFFFFF); 254 } 255 else 256 { 257 /* 32-bit Timer */ 258 259 DeltaTicks = (0xFFFFFFFF - StartTicks) + EndTicks; 260 } 261 } 262 else 263 { 264 *TimeElapsed = 0; 265 return_ACPI_STATUS (AE_OK); 266 } 267 268 /* 269 * Compute Duration: 270 * ----------------- 271 * 272 * Requires a 64-bit divide: 273 * 274 * TimeElapsed = (DeltaTicks * 1000000) / PM_TIMER_FREQUENCY; 275 */ 276 NormalizedTicks.Full = ((UINT64) DeltaTicks) * 1000000; 277 278 Status = AcpiUtShortDivide (&NormalizedTicks.Full, PM_TIMER_FREQUENCY, 279 &OutQuotient, NULL); 280 281 *TimeElapsed = (UINT32) OutQuotient; 282 return_ACPI_STATUS (Status); 283} 284 285 286