drivers/acpi/hardware/hwtimer.c

   1
   2 /******************************************************************************
   3  *
   4  * Name: hwtimer.c - ACPI Power Management Timer Interface
   5  *
   6  *****************************************************************************/
   7
   8 /******************************************************************************
   9  *
  10  * 1. Copyright Notice
  11  *
  12  * Some or all of this work - Copyright (c) 1999 - 2010, Intel Corp.
  13  * All rights reserved.
  14  *
  15  * 2. License
  16  *
  17  * 2.1. This is your license from Intel Corp. under its intellectual property
  18  * rights.  You may have additional license terms from the party that provided
  19  * you this software, covering your right to use that party's intellectual
  20  * property rights.
  21  *
  22  * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
  23  * copy of the source code appearing in this file ("Covered Code") an
  24  * irrevocable, perpetual, worldwide license under Intel's copyrights in the
  25  * base code distributed originally by Intel ("Original Intel Code") to copy,
  26  * make derivatives, distribute, use and display any portion of the Covered
  27  * Code in any form, with the right to sublicense such rights; and
  28  *
  29  * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
  30  * license (with the right to sublicense), under only those claims of Intel
  31  * patents that are infringed by the Original Intel Code, to make, use, sell,
  32  * offer to sell, and import the Covered Code and derivative works thereof
  33  * solely to the minimum extent necessary to exercise the above copyright
  34  * license, and in no event shall the patent license extend to any additions
  35  * to or modifications of the Original Intel Code.  No other license or right
  36  * is granted directly or by implication, estoppel or otherwise;
  37  *
  38  * The above copyright and patent license is granted only if the following
  39  * conditions are met:
  40  *
  41  * 3. Conditions
  42  *
  43  * 3.1. Redistribution of Source with Rights to Further Distribute Source.
  44  * Redistribution of source code of any substantial portion of the Covered
  45  * Code or modification with rights to further distribute source must include
  46  * the above Copyright Notice, the above License, this list of Conditions,
  47  * and the following Disclaimer and Export Compliance provision.  In addition,
  48  * Licensee must cause all Covered Code to which Licensee contributes to
  49  * contain a file documenting the changes Licensee made to create that Covered
  50  * Code and the date of any change.  Licensee must include in that file the
  51  * documentation of any changes made by any predecessor Licensee.  Licensee
  52  * must include a prominent statement that the modification is derived,
  53  * directly or indirectly, from Original Intel Code.
  54  *
  55  * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
  56  * Redistribution of source code of any substantial portion of the Covered
  57  * Code or modification without rights to further distribute source must
  58  * include the following Disclaimer and Export Compliance provision in the
  59  * documentation and/or other materials provided with distribution.  In
  60  * addition, Licensee may not authorize further sublicense of source of any
  61  * portion of the Covered Code, and must include terms to the effect that the
  62  * license from Licensee to its licensee is limited to the intellectual
  63  * property embodied in the software Licensee provides to its licensee, and
  64  * not to intellectual property embodied in modifications its licensee may
  65  * make.
  66  *
  67  * 3.3. Redistribution of Executable. Redistribution in executable form of any
  68  * substantial portion of the Covered Code or modification must reproduce the
  69  * above Copyright Notice, and the following Disclaimer and Export Compliance
  70  * provision in the documentation and/or other materials provided with the
  71  * distribution.
  72  *
  73  * 3.4. Intel retains all right, title, and interest in and to the Original
  74  * Intel Code.
  75  *
  76  * 3.5. Neither the name Intel nor any other trademark owned or controlled by
  77  * Intel shall be used in advertising or otherwise to promote the sale, use or
  78  * other dealings in products derived from or relating to the Covered Code
  79  * without prior written authorization from Intel.
  80  *
  81  * 4. Disclaimer and Export Compliance
  82  *
  83  * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
  84  * HERE.  ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
  85  * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT,  ASSISTANCE,
  86  * INSTALLATION, TRAINING OR OTHER SERVICES.  INTEL WILL NOT PROVIDE ANY
  87  * UPDATES, ENHANCEMENTS OR EXTENSIONS.  INTEL SPECIFICALLY DISCLAIMS ANY
  88  * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
  89  * PARTICULAR PURPOSE.
  90  *
  91  * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
  92  * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
  93  * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
  94  * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
  95  * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
  96  * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.  THESE LIMITATIONS
  97  * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
  98  * LIMITED REMEDY.
  99  *
 100  * 4.3. Licensee shall not export, either directly or indirectly, any of this
 101  * software or system incorporating such software without first obtaining any
 102  * required license or other approval from the U. S. Department of Commerce or
 103  * any other agency or department of the United States Government.  In the
 104  * event Licensee exports any such software from the United States or
 105  * re-exports any such software from a foreign destination, Licensee shall
 106  * ensure that the distribution and export/re-export of the software is in
 107  * compliance with all laws, regulations, orders, or other restrictions of the
 108  * U.S. Export Administration Regulations. Licensee agrees that neither it nor
 109  * any of its subsidiaries will export/re-export any technical data, process,
 110  * software, or service, directly or indirectly, to any country for which the
 111  * United States government or any agency thereof requires an export license,
 112  * other governmental approval, or letter of assurance, without first obtaining
 113  * such license, approval or letter.
 114  *
 115  *****************************************************************************/
 116
 117 #include "acpi.h"
 118 #include "accommon.h"
 119
 120 #define _COMPONENT          ACPI_HARDWARE
 121         ACPI_MODULE_NAME    ("hwtimer")
 122
 123
 124 /******************************************************************************
 125  *
 126  * FUNCTION:    AcpiGetTimerResolution
 127  *
 128  * PARAMETERS:  Resolution          - Where the resolution is returned
 129  *
 130  * RETURN:      Status and timer resolution
 131  *
 132  * DESCRIPTION: Obtains resolution of the ACPI PM Timer (24 or 32 bits).
 133  *
 134  ******************************************************************************/
 135
 136 ACPI_STATUS
 137 AcpiGetTimerResolution (
 138     UINT32                  *Resolution)
 139 {
 140     ACPI_FUNCTION_TRACE (AcpiGetTimerResolution);
 141
 142
 143     if (!Resolution)
 144     {
 145         return_ACPI_STATUS (AE_BAD_PARAMETER);
 146     }
 147
 148     if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) == 0)
 149     {
 150         *Resolution = 24;
 151     }
 152     else
 153     {
 154         *Resolution = 32;
 155     }
 156
 157     return_ACPI_STATUS (AE_OK);
 158 }
 159
 160 ACPI_EXPORT_SYMBOL (AcpiGetTimerResolution)
 161
 162
 163 /******************************************************************************
 164  *
 165  * FUNCTION:    AcpiGetTimer
 166  *
 167  * PARAMETERS:  Ticks               - Where the timer value is returned
 168  *
 169  * RETURN:      Status and current timer value (ticks)
 170  *
 171  * DESCRIPTION: Obtains current value of ACPI PM Timer (in ticks).
 172  *
 173  ******************************************************************************/
 174
 175 ACPI_STATUS
 176 AcpiGetTimer (
 177     UINT32                  *Ticks)
 178 {
 179     ACPI_STATUS             Status;
 180
 181
 182     ACPI_FUNCTION_TRACE (AcpiGetTimer);
 183
 184
 185     if (!Ticks)
 186     {
 187         return_ACPI_STATUS (AE_BAD_PARAMETER);
 188     }
 189
 190     Status = AcpiHwRead (Ticks, &AcpiGbl_FADT.XPmTimerBlock);
 191
 192     return_ACPI_STATUS (Status);
 193 }
 194
 195 ACPI_EXPORT_SYMBOL (AcpiGetTimer)
 196
 197
 198 /******************************************************************************
 199  *
 200  * FUNCTION:    AcpiGetTimerDuration
 201  *
 202  * PARAMETERS:  StartTicks          - Starting timestamp
 203  *              EndTicks            - End timestamp
 204  *              TimeElapsed         - Where the elapsed time is returned
 205  *
 206  * RETURN:      Status and TimeElapsed
 207  *
 208  * DESCRIPTION: Computes the time elapsed (in microseconds) between two
 209  *              PM Timer time stamps, taking into account the possibility of
 210  *              rollovers, the timer resolution, and timer frequency.
 211  *
 212  *              The PM Timer's clock ticks at roughly 3.6 times per
 213  *              _microsecond_, and its clock continues through Cx state
 214  *              transitions (unlike many CPU timestamp counters) -- making it
 215  *              a versatile and accurate timer.
 216  *
 217  *              Note that this function accommodates only a single timer
 218  *              rollover.  Thus for 24-bit timers, this function should only
 219  *              be used for calculating durations less than ~4.6 seconds
 220  *              (~20 minutes for 32-bit timers) -- calculations below:
 221  *
 222  *              2**24 Ticks / 3,600,000 Ticks/Sec = 4.66 sec
 223  *              2**32 Ticks / 3,600,000 Ticks/Sec = 1193 sec or 19.88 minutes
 224  *
 225  ******************************************************************************/
 226
 227 ACPI_STATUS
 228 AcpiGetTimerDuration (
 229     UINT32                  StartTicks,
 230     UINT32                  EndTicks,
 231     UINT32                  *TimeElapsed)
 232 {
 233     ACPI_STATUS             Status;
 234     UINT32                  DeltaTicks;
 235     UINT64                  Quotient;
 236
 237
 238     ACPI_FUNCTION_TRACE (AcpiGetTimerDuration);
 239
 240
 241     if (!TimeElapsed)
 242     {
 243         return_ACPI_STATUS (AE_BAD_PARAMETER);
 244     }
 245
 246     /*
 247      * Compute Tick Delta:
 248      * Handle (max one) timer rollovers on 24-bit versus 32-bit timers.
 249      */
 250     if (StartTicks < EndTicks)
 251     {
 252         DeltaTicks = EndTicks - StartTicks;
 253     }
 254     else if (StartTicks > EndTicks)
 255     {
 256         if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) == 0)
 257         {
 258             /* 24-bit Timer */
 259
 260             DeltaTicks = (((0x00FFFFFF - StartTicks) + EndTicks) & 0x00FFFFFF);
 261         }
 262         else
 263         {
 264             /* 32-bit Timer */
 265
 266             DeltaTicks = (0xFFFFFFFF - StartTicks) + EndTicks;
 267         }
 268     }
 269     else /* StartTicks == EndTicks */
 270     {
 271         *TimeElapsed = 0;
 272         return_ACPI_STATUS (AE_OK);
 273     }
 274
 275     /*
 276      * Compute Duration (Requires a 64-bit multiply and divide):
 277      *
 278      * TimeElapsed = (DeltaTicks * 1000000) / PM_TIMER_FREQUENCY;
 279      */
 280     Status = AcpiUtShortDivide (((UINT64) DeltaTicks) * 1000000,
 281                 PM_TIMER_FREQUENCY, &Quotient, NULL);
 282
 283     *TimeElapsed = (UINT32) Quotient;
 284     return_ACPI_STATUS (Status);
 285 }
 286
 287 ACPI_EXPORT_SYMBOL (AcpiGetTimerDuration)
 288