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/****************************************************************************** |
* |
* Name: hwtimer.c - ACPI Power Management Timer Interface |
* |
*****************************************************************************/ |
|
/* |
* Copyright (C) 2000 - 2015, 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. |
*/ |
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#define EXPORT_ACPI_INTERFACES |
|
#include <acpi/acpi.h> |
#include "accommon.h" |
|
#define _COMPONENT ACPI_HARDWARE |
ACPI_MODULE_NAME("hwtimer") |
|
#if (!ACPI_REDUCED_HARDWARE) /* Entire module */ |
/****************************************************************************** |
* |
* FUNCTION: acpi_get_timer_resolution |
* |
* 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 acpi_get_timer_resolution(u32 * resolution) |
{ |
ACPI_FUNCTION_TRACE(acpi_get_timer_resolution); |
|
if (!resolution) { |
return_ACPI_STATUS(AE_BAD_PARAMETER); |
} |
|
if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) { |
*resolution = 24; |
} else { |
*resolution = 32; |
} |
|
return_ACPI_STATUS(AE_OK); |
} |
|
ACPI_EXPORT_SYMBOL(acpi_get_timer_resolution) |
|
/****************************************************************************** |
* |
* FUNCTION: acpi_get_timer |
* |
* 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 acpi_get_timer(u32 * ticks) |
{ |
acpi_status status; |
|
ACPI_FUNCTION_TRACE(acpi_get_timer); |
|
if (!ticks) { |
return_ACPI_STATUS(AE_BAD_PARAMETER); |
} |
|
/* ACPI 5.0A: PM Timer is optional */ |
|
if (!acpi_gbl_FADT.xpm_timer_block.address) { |
return_ACPI_STATUS(AE_SUPPORT); |
} |
|
status = acpi_hw_read(ticks, &acpi_gbl_FADT.xpm_timer_block); |
return_ACPI_STATUS(status); |
} |
|
ACPI_EXPORT_SYMBOL(acpi_get_timer) |
|
/****************************************************************************** |
* |
* FUNCTION: acpi_get_timer_duration |
* |
* PARAMETERS: start_ticks - Starting timestamp |
* end_ticks - End timestamp |
* time_elapsed - Where the elapsed time is returned |
* |
* RETURN: Status and time_elapsed |
* |
* 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 |
acpi_get_timer_duration(u32 start_ticks, u32 end_ticks, u32 * time_elapsed) |
{ |
acpi_status status; |
u32 delta_ticks; |
u64 quotient; |
|
ACPI_FUNCTION_TRACE(acpi_get_timer_duration); |
|
if (!time_elapsed) { |
return_ACPI_STATUS(AE_BAD_PARAMETER); |
} |
|
/* ACPI 5.0A: PM Timer is optional */ |
|
if (!acpi_gbl_FADT.xpm_timer_block.address) { |
return_ACPI_STATUS(AE_SUPPORT); |
} |
|
/* |
* Compute Tick Delta: |
* Handle (max one) timer rollovers on 24-bit versus 32-bit timers. |
*/ |
if (start_ticks < end_ticks) { |
delta_ticks = end_ticks - start_ticks; |
} else if (start_ticks > end_ticks) { |
if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) { |
|
/* 24-bit Timer */ |
|
delta_ticks = |
(((0x00FFFFFF - start_ticks) + |
end_ticks) & 0x00FFFFFF); |
} else { |
/* 32-bit Timer */ |
|
delta_ticks = (0xFFFFFFFF - start_ticks) + end_ticks; |
} |
} else { /* start_ticks == end_ticks */ |
|
*time_elapsed = 0; |
return_ACPI_STATUS(AE_OK); |
} |
|
/* |
* Compute Duration (Requires a 64-bit multiply and divide): |
* |
* time_elapsed (microseconds) = |
* (delta_ticks * ACPI_USEC_PER_SEC) / ACPI_PM_TIMER_FREQUENCY; |
*/ |
status = acpi_ut_short_divide(((u64)delta_ticks) * ACPI_USEC_PER_SEC, |
ACPI_PM_TIMER_FREQUENCY, "ient, NULL); |
|
*time_elapsed = (u32) quotient; |
return_ACPI_STATUS(status); |
} |
|
ACPI_EXPORT_SYMBOL(acpi_get_timer_duration) |
#endif /* !ACPI_REDUCED_HARDWARE */ |