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Diffstat (limited to 'source/components/hardware/hwtimer.c')
| -rw-r--r-- | source/components/hardware/hwtimer.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/source/components/hardware/hwtimer.c b/source/components/hardware/hwtimer.c new file mode 100644 index 000000000000..15dc58f0bffe --- /dev/null +++ b/source/components/hardware/hwtimer.c @@ -0,0 +1,218 @@ + +/****************************************************************************** + * + * Name: hwtimer.c - ACPI Power Management Timer Interface + * + *****************************************************************************/ + +/* + * Copyright (C) 2000 - 2012, 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. + */ + +#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); + } + + 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); + } + + /* + * 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 = (DeltaTicks * 1000000) / PM_TIMER_FREQUENCY; + */ + Status = AcpiUtShortDivide (((UINT64) DeltaTicks) * 1000000, + PM_TIMER_FREQUENCY, &Quotient, NULL); + + *TimeElapsed = (UINT32) Quotient; + return_ACPI_STATUS (Status); +} + +ACPI_EXPORT_SYMBOL (AcpiGetTimerDuration) + +#endif /* !ACPI_REDUCED_HARDWARE */ |