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

   1 /******************************************************************************
   2  *
   3  * Name: hwtimer.c - ACPI Power Management Timer Interface
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2022, 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 MERCHANTABILITY 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.h"
  47 #include "accommon.h"
  48
  49 #define _COMPONENT          ACPI_HARDWARE
  50         ACPI_MODULE_NAME    ("hwtimer")
  51
  52
  53 #if (!ACPI_REDUCED_HARDWARE) /* Entire module */
  54 /******************************************************************************
  55  *
  56  * FUNCTION:    AcpiGetTimerResolution
  57  *
  58  * PARAMETERS:  Resolution          - Where the resolution is returned
  59  *
  60  * RETURN:      Status and timer resolution
  61  *
  62  * DESCRIPTION: Obtains resolution of the ACPI PM Timer (24 or 32 bits).
  63  *
  64  ******************************************************************************/
  65
  66 ACPI_STATUS
  67 AcpiGetTimerResolution (
  68     UINT32                  *Resolution)
  69 {
  70     ACPI_FUNCTION_TRACE (AcpiGetTimerResolution);
  71
  72
  73     if (!Resolution)
  74     {
  75         return_ACPI_STATUS (AE_BAD_PARAMETER);
  76     }
  77
  78     if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) == 0)
  79     {
  80         *Resolution = 24;
  81     }
  82     else
  83     {
  84         *Resolution = 32;
  85     }
  86
  87     return_ACPI_STATUS (AE_OK);
  88 }
  89
  90 ACPI_EXPORT_SYMBOL (AcpiGetTimerResolution)
  91
  92
  93 /******************************************************************************
  94  *
  95  * FUNCTION:    AcpiGetTimer
  96  *
  97  * PARAMETERS:  Ticks               - Where the timer value is returned
  98  *
  99  * RETURN:      Status and current timer value (ticks)
 100  *
 101  * DESCRIPTION: Obtains current value of ACPI PM Timer (in ticks).
 102  *
 103  ******************************************************************************/
 104
 105 ACPI_STATUS
 106 AcpiGetTimer (
 107     UINT32                  *Ticks)
 108 {
 109     ACPI_STATUS             Status;
 110     UINT64                  TimerValue;
 111
 112
 113     ACPI_FUNCTION_TRACE (AcpiGetTimer);
 114
 115
 116     if (!Ticks)
 117     {
 118         return_ACPI_STATUS (AE_BAD_PARAMETER);
 119     }
 120
 121     /* ACPI 5.0A: PM Timer is optional */
 122
 123     if (!AcpiGbl_FADT.XPmTimerBlock.Address)
 124     {
 125         return_ACPI_STATUS (AE_SUPPORT);
 126     }
 127
 128     Status = AcpiHwRead (&TimerValue, &AcpiGbl_FADT.XPmTimerBlock);
 129     if (ACPI_SUCCESS (Status))
 130     {
 131         /* ACPI PM Timer is defined to be 32 bits (PM_TMR_LEN) */
 132
 133         *Ticks = (UINT32) TimerValue;
 134     }
 135
 136     return_ACPI_STATUS (Status);
 137 }
 138
 139 ACPI_EXPORT_SYMBOL (AcpiGetTimer)
 140
 141
 142 /******************************************************************************
 143  *
 144  * FUNCTION:    AcpiGetTimerDuration
 145  *
 146  * PARAMETERS:  StartTicks          - Starting timestamp
 147  *              EndTicks            - End timestamp
 148  *              TimeElapsed         - Where the elapsed time is returned
 149  *
 150  * RETURN:      Status and TimeElapsed
 151  *
 152  * DESCRIPTION: Computes the time elapsed (in microseconds) between two
 153  *              PM Timer time stamps, taking into account the possibility of
 154  *              rollovers, the timer resolution, and timer frequency.
 155  *
 156  *              The PM Timer's clock ticks at roughly 3.6 times per
 157  *              _microsecond_, and its clock continues through Cx state
 158  *              transitions (unlike many CPU timestamp counters) -- making it
 159  *              a versatile and accurate timer.
 160  *
 161  *              Note that this function accommodates only a single timer
 162  *              rollover. Thus for 24-bit timers, this function should only
 163  *              be used for calculating durations less than ~4.6 seconds
 164  *              (~20 minutes for 32-bit timers) -- calculations below:
 165  *
 166  *              2**24 Ticks / 3,600,000 Ticks/Sec = 4.66 sec
 167  *              2**32 Ticks / 3,600,000 Ticks/Sec = 1193 sec or 19.88 minutes
 168  *
 169  ******************************************************************************/
 170
 171 ACPI_STATUS
 172 AcpiGetTimerDuration (
 173     UINT32                  StartTicks,
 174     UINT32                  EndTicks,
 175     UINT32                  *TimeElapsed)
 176 {
 177     ACPI_STATUS             Status;
 178     UINT64                  DeltaTicks;
 179     UINT64                  Quotient;
 180
 181
 182     ACPI_FUNCTION_TRACE (AcpiGetTimerDuration);
 183
 184
 185     if (!TimeElapsed)
 186     {
 187         return_ACPI_STATUS (AE_BAD_PARAMETER);
 188     }
 189
 190     /* ACPI 5.0A: PM Timer is optional */
 191
 192     if (!AcpiGbl_FADT.XPmTimerBlock.Address)
 193     {
 194         return_ACPI_STATUS (AE_SUPPORT);
 195     }
 196
 197     if (StartTicks == EndTicks)
 198     {
 199         *TimeElapsed = 0;
 200         return_ACPI_STATUS (AE_OK);
 201     }
 202
 203     /*
 204      * Compute Tick Delta:
 205      * Handle (max one) timer rollovers on 24-bit versus 32-bit timers.
 206      */
 207     DeltaTicks = EndTicks;
 208     if (StartTicks > EndTicks)
 209     {
 210         if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) == 0)
 211         {
 212             /* 24-bit Timer */
 213
 214             DeltaTicks |= (UINT64) 1 << 24;
 215         }
 216         else
 217         {
 218             /* 32-bit Timer */
 219
 220             DeltaTicks |= (UINT64) 1 << 32;
 221         }
 222     }
 223     DeltaTicks -= StartTicks;
 224
 225     /*
 226      * Compute Duration (Requires a 64-bit multiply and divide):
 227      *
 228      * TimeElapsed (microseconds) =
 229      *  (DeltaTicks * ACPI_USEC_PER_SEC) / ACPI_PM_TIMER_FREQUENCY;
 230      */
 231     Status = AcpiUtShortDivide (DeltaTicks * ACPI_USEC_PER_SEC,
 232                 ACPI_PM_TIMER_FREQUENCY, &Quotient, NULL);
 233
 234     *TimeElapsed = (UINT32) Quotient;
 235     return_ACPI_STATUS (Status);
 236 }
 237
 238 ACPI_EXPORT_SYMBOL (AcpiGetTimerDuration)
 239
 240 #endif /* !ACPI_REDUCED_HARDWARE */