drivers/bus/acpi/acpica/hardware/hwtimer.c

   1 /******************************************************************************
   2  *
   3  * Name: hwtimer.c - ACPI Power Management Timer Interface
   4  *
   5  *****************************************************************************/
   6
   7 /******************************************************************************
   8  *
   9  * 1. Copyright Notice
  10  *
  11  * Some or all of this work - Copyright (c) 1999 - 2014, Intel Corp.
  12  * All rights reserved.
  13  *
  14  * 2. License
  15  *
  16  * 2.1. This is your license from Intel Corp. under its intellectual property
  17  * rights. You may have additional license terms from the party that provided
  18  * you this software, covering your right to use that party's intellectual
  19  * property rights.
  20  *
  21  * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
  22  * copy of the source code appearing in this file ("Covered Code") an
  23  * irrevocable, perpetual, worldwide license under Intel's copyrights in the
  24  * base code distributed originally by Intel ("Original Intel Code") to copy,
  25  * make derivatives, distribute, use and display any portion of the Covered
  26  * Code in any form, with the right to sublicense such rights; and
  27  *
  28  * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
  29  * license (with the right to sublicense), under only those claims of Intel
  30  * patents that are infringed by the Original Intel Code, to make, use, sell,
  31  * offer to sell, and import the Covered Code and derivative works thereof
  32  * solely to the minimum extent necessary to exercise the above copyright
  33  * license, and in no event shall the patent license extend to any additions
  34  * to or modifications of the Original Intel Code. No other license or right
  35  * is granted directly or by implication, estoppel or otherwise;
  36  *
  37  * The above copyright and patent license is granted only if the following
  38  * conditions are met:
  39  *
  40  * 3. Conditions
  41  *
  42  * 3.1. Redistribution of Source with Rights to Further Distribute Source.
  43  * Redistribution of source code of any substantial portion of the Covered
  44  * Code or modification with rights to further distribute source must include
  45  * the above Copyright Notice, the above License, this list of Conditions,
  46  * and the following Disclaimer and Export Compliance provision. In addition,
  47  * Licensee must cause all Covered Code to which Licensee contributes to
  48  * contain a file documenting the changes Licensee made to create that Covered
  49  * Code and the date of any change. Licensee must include in that file the
  50  * documentation of any changes made by any predecessor Licensee. Licensee
  51  * must include a prominent statement that the modification is derived,
  52  * directly or indirectly, from Original Intel Code.
  53  *
  54  * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
  55  * Redistribution of source code of any substantial portion of the Covered
  56  * Code or modification without rights to further distribute source must
  57  * include the following Disclaimer and Export Compliance provision in the
  58  * documentation and/or other materials provided with distribution. In
  59  * addition, Licensee may not authorize further sublicense of source of any
  60  * portion of the Covered Code, and must include terms to the effect that the
  61  * license from Licensee to its licensee is limited to the intellectual
  62  * property embodied in the software Licensee provides to its licensee, and
  63  * not to intellectual property embodied in modifications its licensee may
  64  * make.
  65  *
  66  * 3.3. Redistribution of Executable. Redistribution in executable form of any
  67  * substantial portion of the Covered Code or modification must reproduce the
  68  * above Copyright Notice, and the following Disclaimer and Export Compliance
  69  * provision in the documentation and/or other materials provided with the
  70  * distribution.
  71  *
  72  * 3.4. Intel retains all right, title, and interest in and to the Original
  73  * Intel Code.
  74  *
  75  * 3.5. Neither the name Intel nor any other trademark owned or controlled by
  76  * Intel shall be used in advertising or otherwise to promote the sale, use or
  77  * other dealings in products derived from or relating to the Covered Code
  78  * without prior written authorization from Intel.
  79  *
  80  * 4. Disclaimer and Export Compliance
  81  *
  82  * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
  83  * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
  84  * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE,
  85  * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY
  86  * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY
  87  * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
  88  * PARTICULAR PURPOSE.
  89  *
  90  * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
  91  * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
  92  * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
  93  * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
  94  * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
  95  * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS
  96  * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
  97  * LIMITED REMEDY.
  98  *
  99  * 4.3. Licensee shall not export, either directly or indirectly, any of this
 100  * software or system incorporating such software without first obtaining any
 101  * required license or other approval from the U. S. Department of Commerce or
 102  * any other agency or department of the United States Government. In the
 103  * event Licensee exports any such software from the United States or
 104  * re-exports any such software from a foreign destination, Licensee shall
 105  * ensure that the distribution and export/re-export of the software is in
 106  * compliance with all laws, regulations, orders, or other restrictions of the
 107  * U.S. Export Administration Regulations. Licensee agrees that neither it nor
 108  * any of its subsidiaries will export/re-export any technical data, process,
 109  * software, or service, directly or indirectly, to any country for which the
 110  * United States government or any agency thereof requires an export license,
 111  * other governmental approval, or letter of assurance, without first obtaining
 112  * such license, approval or letter.
 113  *
 114  *****************************************************************************/
 115
 116 #define EXPORT_ACPI_INTERFACES
 117
 118 #include "acpi.h"
 119 #include "accommon.h"
 120
 121 #define _COMPONENT          ACPI_HARDWARE
 122         ACPI_MODULE_NAME    ("hwtimer")
 123
 124
 125 #if (!ACPI_REDUCED_HARDWARE) /* Entire module */
 126 /******************************************************************************
 127  *
 128  * FUNCTION:    AcpiGetTimerResolution
 129  *
 130  * PARAMETERS:  Resolution          - Where the resolution is returned
 131  *
 132  * RETURN:      Status and timer resolution
 133  *
 134  * DESCRIPTION: Obtains resolution of the ACPI PM Timer (24 or 32 bits).
 135  *
 136  ******************************************************************************/
 137
 138 ACPI_STATUS
 139 AcpiGetTimerResolution (
 140     UINT32                  *Resolution)
 141 {
 142     ACPI_FUNCTION_TRACE (AcpiGetTimerResolution);
 143
 144
 145     if (!Resolution)
 146     {
 147         return_ACPI_STATUS (AE_BAD_PARAMETER);
 148     }
 149
 150     if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) == 0)
 151     {
 152         *Resolution = 24;
 153     }
 154     else
 155     {
 156         *Resolution = 32;
 157     }
 158
 159     return_ACPI_STATUS (AE_OK);
 160 }
 161
 162 ACPI_EXPORT_SYMBOL (AcpiGetTimerResolution)
 163
 164
 165 /******************************************************************************
 166  *
 167  * FUNCTION:    AcpiGetTimer
 168  *
 169  * PARAMETERS:  Ticks               - Where the timer value is returned
 170  *
 171  * RETURN:      Status and current timer value (ticks)
 172  *
 173  * DESCRIPTION: Obtains current value of ACPI PM Timer (in ticks).
 174  *
 175  ******************************************************************************/
 176
 177 ACPI_STATUS
 178 AcpiGetTimer (
 179     UINT32                  *Ticks)
 180 {
 181     ACPI_STATUS             Status;
 182
 183
 184     ACPI_FUNCTION_TRACE (AcpiGetTimer);
 185
 186
 187     if (!Ticks)
 188     {
 189         return_ACPI_STATUS (AE_BAD_PARAMETER);
 190     }
 191
 192     /* ACPI 5.0A: PM Timer is optional */
 193
 194     if (!AcpiGbl_FADT.XPmTimerBlock.Address)
 195     {
 196         return_ACPI_STATUS (AE_SUPPORT);
 197     }
 198
 199     Status = AcpiHwRead (Ticks, &AcpiGbl_FADT.XPmTimerBlock);
 200     return_ACPI_STATUS (Status);
 201 }
 202
 203 ACPI_EXPORT_SYMBOL (AcpiGetTimer)
 204
 205
 206 /******************************************************************************
 207  *
 208  * FUNCTION:    AcpiGetTimerDuration
 209  *
 210  * PARAMETERS:  StartTicks          - Starting timestamp
 211  *              EndTicks            - End timestamp
 212  *              TimeElapsed         - Where the elapsed time is returned
 213  *
 214  * RETURN:      Status and TimeElapsed
 215  *
 216  * DESCRIPTION: Computes the time elapsed (in microseconds) between two
 217  *              PM Timer time stamps, taking into account the possibility of
 218  *              rollovers, the timer resolution, and timer frequency.
 219  *
 220  *              The PM Timer's clock ticks at roughly 3.6 times per
 221  *              _microsecond_, and its clock continues through Cx state
 222  *              transitions (unlike many CPU timestamp counters) -- making it
 223  *              a versatile and accurate timer.
 224  *
 225  *              Note that this function accommodates only a single timer
 226  *              rollover. Thus for 24-bit timers, this function should only
 227  *              be used for calculating durations less than ~4.6 seconds
 228  *              (~20 minutes for 32-bit timers) -- calculations below:
 229  *
 230  *              2**24 Ticks / 3,600,000 Ticks/Sec = 4.66 sec
 231  *              2**32 Ticks / 3,600,000 Ticks/Sec = 1193 sec or 19.88 minutes
 232  *
 233  ******************************************************************************/
 234
 235 ACPI_STATUS
 236 AcpiGetTimerDuration (
 237     UINT32                  StartTicks,
 238     UINT32                  EndTicks,
 239     UINT32                  *TimeElapsed)
 240 {
 241     ACPI_STATUS             Status;
 242     UINT32                  DeltaTicks;
 243     UINT64                  Quotient;
 244
 245
 246     ACPI_FUNCTION_TRACE (AcpiGetTimerDuration);
 247
 248
 249     if (!TimeElapsed)
 250     {
 251         return_ACPI_STATUS (AE_BAD_PARAMETER);
 252     }
 253
 254     /* ACPI 5.0A: PM Timer is optional */
 255
 256     if (!AcpiGbl_FADT.XPmTimerBlock.Address)
 257     {
 258         return_ACPI_STATUS (AE_SUPPORT);
 259     }
 260
 261     /*
 262      * Compute Tick Delta:
 263      * Handle (max one) timer rollovers on 24-bit versus 32-bit timers.
 264      */
 265     if (StartTicks < EndTicks)
 266     {
 267         DeltaTicks = EndTicks - StartTicks;
 268     }
 269     else if (StartTicks > EndTicks)
 270     {
 271         if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) == 0)
 272         {
 273             /* 24-bit Timer */
 274
 275             DeltaTicks = (((0x00FFFFFF - StartTicks) + EndTicks) & 0x00FFFFFF);
 276         }
 277         else
 278         {
 279             /* 32-bit Timer */
 280
 281             DeltaTicks = (0xFFFFFFFF - StartTicks) + EndTicks;
 282         }
 283     }
 284     else /* StartTicks == EndTicks */
 285     {
 286         *TimeElapsed = 0;
 287         return_ACPI_STATUS (AE_OK);
 288     }
 289
 290     /*
 291      * Compute Duration (Requires a 64-bit multiply and divide):
 292      *
 293      * TimeElapsed (microseconds) =
 294      *  (DeltaTicks * ACPI_USEC_PER_SEC) / ACPI_PM_TIMER_FREQUENCY;
 295      */
 296     Status = AcpiUtShortDivide (((UINT64) DeltaTicks) * ACPI_USEC_PER_SEC,
 297                 ACPI_PM_TIMER_FREQUENCY, &Quotient, NULL);
 298
 299     *TimeElapsed = (UINT32) Quotient;
 300     return_ACPI_STATUS (Status);
 301 }
 302
 303 ACPI_EXPORT_SYMBOL (AcpiGetTimerDuration)
 304
 305 #endif /* !ACPI_REDUCED_HARDWARE */