hwtimer.c revision 78986
1 2/****************************************************************************** 3 * 4 * Name: hwtimer.c - ACPI Power Management Timer Interface 5 * $Revision: 10 $ 6 * 7 *****************************************************************************/ 8 9/****************************************************************************** 10 * 11 * 1. Copyright Notice 12 * 13 * Some or all of this work - Copyright (c) 1999, 2000, 2001, 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 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_STATUS Status; 142 143 144 FUNCTION_TRACE ("AcpiGetTimerResolution"); 145 146 147 /* Ensure that ACPI has been initialized */ 148 149 ACPI_IS_INITIALIZATION_COMPLETE (Status); 150 if (ACPI_FAILURE (Status)) 151 { 152 return_ACPI_STATUS (Status); 153 } 154 155 if (!Resolution) 156 { 157 return_ACPI_STATUS (AE_BAD_PARAMETER); 158 } 159 160 if (0 == AcpiGbl_FADT->TmrValExt) 161 { 162 *Resolution = 24; 163 } 164 else 165 { 166 *Resolution = 32; 167 } 168 169 return_ACPI_STATUS (AE_OK); 170} 171 172 173/****************************************************************************** 174 * 175 * FUNCTION: AcpiGetTimer 176 * 177 * PARAMETERS: none 178 * 179 * RETURN: Current value of the ACPI PM Timer (in ticks). 180 * 181 * DESCRIPTION: Obtains current value of ACPI PM Timer. 182 * 183 ******************************************************************************/ 184 185ACPI_STATUS 186AcpiGetTimer ( 187 UINT32 *Ticks) 188{ 189 ACPI_STATUS Status; 190 191 192 FUNCTION_TRACE ("AcpiGetTimer"); 193 194 195 /* Ensure that ACPI has been initialized */ 196 197 ACPI_IS_INITIALIZATION_COMPLETE (Status); 198 if (ACPI_FAILURE (Status)) 199 { 200 return_ACPI_STATUS (Status); 201 } 202 203 if (!Ticks) 204 { 205 return_ACPI_STATUS (AE_BAD_PARAMETER); 206 } 207 208 *Ticks = AcpiOsIn32 ((ACPI_IO_ADDRESS) ACPI_GET_ADDRESS (AcpiGbl_FADT->XPmTmrBlk.Address)); 209 210 return_ACPI_STATUS (AE_OK); 211} 212 213 214/****************************************************************************** 215 * 216 * FUNCTION: AcpiGetTimerDuration 217 * 218 * PARAMETERS: StartTicks 219 * EndTicks 220 * TimeElapsed 221 * 222 * RETURN: TimeElapsed 223 * 224 * DESCRIPTION: Computes the time elapsed (in microseconds) between two 225 * PM Timer time stamps, taking into account the possibility of 226 * rollovers, the timer resolution, and timer frequency. 227 * 228 * The PM Timer's clock ticks at roughly 3.6 times per 229 * _microsecond_, and its clock continues through Cx state 230 * transitions (unlike many CPU timestamp counters) -- making it 231 * a versatile and accurate timer. 232 * 233 * Note that this function accomodates only a single timer 234 * rollover. Thus for 24-bit timers, this function should only 235 * be used for calculating durations less than ~4.6 seconds 236 * (~20 hours for 32-bit timers). 237 * 238 ******************************************************************************/ 239 240ACPI_STATUS 241AcpiGetTimerDuration ( 242 UINT32 StartTicks, 243 UINT32 EndTicks, 244 UINT32 *TimeElapsed) 245{ 246 UINT32 DeltaTicks = 0; 247 UINT32 Seconds = 0; 248 UINT32 Milliseconds = 0; 249 UINT32 Microseconds = 0; 250 UINT32 Remainder = 0; 251 252 253 FUNCTION_TRACE ("AcpiGetTimerDuration"); 254 255 if (!TimeElapsed) 256 { 257 return_ACPI_STATUS (AE_BAD_PARAMETER); 258 } 259 260 /* 261 * Compute Tick Delta: 262 * ------------------- 263 * Handle (max one) timer rollovers on 24- versus 32-bit timers. 264 */ 265 if (StartTicks < EndTicks) 266 { 267 DeltaTicks = EndTicks - StartTicks; 268 } 269 else if (StartTicks > EndTicks) 270 { 271 /* 24-bit Timer */ 272 if (0 == AcpiGbl_FADT->TmrValExt) 273 { 274 DeltaTicks = (((0x00FFFFFF - StartTicks) + EndTicks) & 0x00FFFFFF); 275 } 276 /* 32-bit Timer */ 277 else 278 { 279 DeltaTicks = (0xFFFFFFFF - StartTicks) + EndTicks; 280 } 281 } 282 else 283 { 284 *TimeElapsed = 0; 285 return_ACPI_STATUS (AE_OK); 286 } 287 288 /* 289 * Compute Duration: 290 * ----------------- 291 * Since certain compilers (gcc/Linux, argh!) don't support 64-bit 292 * divides in kernel-space we have to do some trickery to preserve 293 * accuracy while using 32-bit math. 294 * 295 * TBD: Change to use 64-bit math when supported. 296 * 297 * The process is as follows: 298 * 1. Compute the number of seconds by dividing Delta Ticks by 299 * the timer frequency. 300 * 2. Compute the number of milliseconds in the remainder from step #1 301 * by multiplying by 1000 and then dividing by the timer frequency. 302 * 3. Compute the number of microseconds in the remainder from step #2 303 * by multiplying by 1000 and then dividing by the timer frequency. 304 * 4. Add the results from steps 1, 2, and 3 to get the total duration. 305 * 306 * Example: The time elapsed for DeltaTicks = 0xFFFFFFFF should be 307 * 1199864031 microseconds. This is computed as follows: 308 * Step #1: Seconds = 1199; Remainder = 3092840 309 * Step #2: Milliseconds = 864; Remainder = 113120 310 * Step #3: Microseconds = 31; Remainder = <don't care!> 311 */ 312 313 /* Step #1 */ 314 Seconds = DeltaTicks / PM_TIMER_FREQUENCY; 315 Remainder = DeltaTicks % PM_TIMER_FREQUENCY; 316 317 /* Step #2 */ 318 Milliseconds = (Remainder * 1000) / PM_TIMER_FREQUENCY; 319 Remainder = (Remainder * 1000) % PM_TIMER_FREQUENCY; 320 321 /* Step #3 */ 322 Microseconds = (Remainder * 1000) / PM_TIMER_FREQUENCY; 323 324 /* Step #4 */ 325 *TimeElapsed = Seconds * 1000000; 326 *TimeElapsed += Milliseconds * 1000; 327 *TimeElapsed += Microseconds; 328 329 return_ACPI_STATUS (AE_OK); 330} 331 332 333