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// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
/******************************************************************************
*
* Name: hwtimer.c - ACPI Power Management Timer Interface
*
* Copyright (C) 2000 - 2020, Intel Corp.
*
*****************************************************************************/
#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;
u64 timer_value;
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(&timer_value, &acpi_gbl_FADT.xpm_timer_block);
if (ACPI_SUCCESS(status)) {
/* ACPI PM Timer is defined to be 32 bits (PM_TMR_LEN) */
*ticks = (u32)timer_value;
}
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;
u64 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);
}
if (start_ticks == end_ticks) {
*time_elapsed = 0;
return_ACPI_STATUS(AE_OK);
}
/*
* Compute Tick Delta:
* Handle (max one) timer rollovers on 24-bit versus 32-bit timers.
*/
delta_ticks = end_ticks;
if (start_ticks > end_ticks) {
if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) {
/* 24-bit Timer */
delta_ticks |= (u64)1 << 24;
} else {
/* 32-bit Timer */
delta_ticks |= (u64)1 << 32;
}
}
delta_ticks -= start_ticks;
/*
* 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(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 */
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