/******************************************************************************
*
* Name: hwtimer.c - ACPI Power Management Timer Interface
*
*****************************************************************************/
/*
* Copyright (C) 2000 - 2014, Intel Corp.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions, and the following disclaimer,
* without modification.
* 2. Redistributions in binary form must reproduce at minimum a disclaimer
* substantially similar to the "NO WARRANTY" disclaimer below
* ("Disclaimer") and any redistribution must be conditioned upon
* including a substantially similar Disclaimer requirement for further
* binary redistribution.
* 3. Neither the names of the above-listed copyright holders nor the names
* of any contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* NO WARRANTY
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*/
#define EXPORT_ACPI_INTERFACES
#include "acpi.h"
#include "accommon.h"
#define _COMPONENT ACPI_HARDWARE
ACPI_MODULE_NAME ("hwtimer")
#if (!ACPI_REDUCED_HARDWARE) /* Entire module */
/******************************************************************************
*
* FUNCTION: AcpiGetTimerResolution
*
* PARAMETERS: Resolution - Where the resolution is returned
*
* RETURN: Status and timer resolution
*
* DESCRIPTION: Obtains resolution of the ACPI PM Timer (24 or 32 bits).
*
******************************************************************************/
ACPI_STATUS
AcpiGetTimerResolution (
UINT32 *Resolution)
{
ACPI_FUNCTION_TRACE (AcpiGetTimerResolution);
if (!Resolution)
{
return_ACPI_STATUS (AE_BAD_PARAMETER);
}
if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) == 0)
{
*Resolution = 24;
}
else
{
*Resolution = 32;
}
return_ACPI_STATUS (AE_OK);
}
ACPI_EXPORT_SYMBOL (AcpiGetTimerResolution)
/******************************************************************************
*
* FUNCTION: AcpiGetTimer
*
* PARAMETERS: Ticks - Where the timer value is returned
*
* RETURN: Status and current timer value (ticks)
*
* DESCRIPTION: Obtains current value of ACPI PM Timer (in ticks).
*
******************************************************************************/
ACPI_STATUS
AcpiGetTimer (
UINT32 *Ticks)
{
ACPI_STATUS Status;
ACPI_FUNCTION_TRACE (AcpiGetTimer);
if (!Ticks)
{
return_ACPI_STATUS (AE_BAD_PARAMETER);
}
/* ACPI 5.0A: PM Timer is optional */
if (!AcpiGbl_FADT.XPmTimerBlock.Address)
{
return_ACPI_STATUS (AE_SUPPORT);
}
Status = AcpiHwRead (Ticks, &AcpiGbl_FADT.XPmTimerBlock);
return_ACPI_STATUS (Status);
}
ACPI_EXPORT_SYMBOL (AcpiGetTimer)
/******************************************************************************
*
* FUNCTION: AcpiGetTimerDuration
*
* PARAMETERS: StartTicks - Starting timestamp
* EndTicks - End timestamp
* TimeElapsed - Where the elapsed time is returned
*
* RETURN: Status and TimeElapsed
*
* DESCRIPTION: Computes the time elapsed (in microseconds) between two
* PM Timer time stamps, taking into account the possibility of
* rollovers, the timer resolution, and timer frequency.
*
* The PM Timer's clock ticks at roughly 3.6 times per
* _microsecond_, and its clock continues through Cx state
* transitions (unlike many CPU timestamp counters) -- making it
* a versatile and accurate timer.
*
* Note that this function accommodates only a single timer
* rollover. Thus for 24-bit timers, this function should only
* be used for calculating durations less than ~4.6 seconds
* (~20 minutes for 32-bit timers) -- calculations below:
*
* 2**24 Ticks / 3,600,000 Ticks/Sec = 4.66 sec
* 2**32 Ticks / 3,600,000 Ticks/Sec = 1193 sec or 19.88 minutes
*
******************************************************************************/
ACPI_STATUS
AcpiGetTimerDuration (
UINT32 StartTicks,
UINT32 EndTicks,
UINT32 *TimeElapsed)
{
ACPI_STATUS Status;
UINT32 DeltaTicks;
UINT64 Quotient;
ACPI_FUNCTION_TRACE (AcpiGetTimerDuration);
if (!TimeElapsed)
{
return_ACPI_STATUS (AE_BAD_PARAMETER);
}
/* ACPI 5.0A: PM Timer is optional */
if (!AcpiGbl_FADT.XPmTimerBlock.Address)
{
return_ACPI_STATUS (AE_SUPPORT);
}
/*
* Compute Tick Delta:
* Handle (max one) timer rollovers on 24-bit versus 32-bit timers.
*/
if (StartTicks < EndTicks)
{
DeltaTicks = EndTicks - StartTicks;
}
else if (StartTicks > EndTicks)
{
if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) == 0)
{
/* 24-bit Timer */
DeltaTicks = (((0x00FFFFFF - StartTicks) + EndTicks) & 0x00FFFFFF);
}
else
{
/* 32-bit Timer */
DeltaTicks = (0xFFFFFFFF - StartTicks) + EndTicks;
}
}
else /* StartTicks == EndTicks */
{
*TimeElapsed = 0;
return_ACPI_STATUS (AE_OK);
}
/*
* Compute Duration (Requires a 64-bit multiply and divide):
*
* TimeElapsed (microseconds) =
* (DeltaTicks * ACPI_USEC_PER_SEC) / ACPI_PM_TIMER_FREQUENCY;
*/
Status = AcpiUtShortDivide (((UINT64) DeltaTicks) * ACPI_USEC_PER_SEC,
ACPI_PM_TIMER_FREQUENCY, &Quotient, NULL);
*TimeElapsed = (UINT32) Quotient;
return_ACPI_STATUS (Status);
}
ACPI_EXPORT_SYMBOL (AcpiGetTimerDuration)
#endif /* !ACPI_REDUCED_HARDWARE */
