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175 lines
4.8 KiB
175 lines
4.8 KiB
// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 |
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/****************************************************************************** |
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* |
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* Name: hwtimer.c - ACPI Power Management Timer Interface |
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* |
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* Copyright (C) 2000 - 2021, Intel Corp. |
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* |
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*****************************************************************************/ |
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#define EXPORT_ACPI_INTERFACES |
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#include <acpi/acpi.h> |
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#include "accommon.h" |
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#define _COMPONENT ACPI_HARDWARE |
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ACPI_MODULE_NAME("hwtimer") |
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#if (!ACPI_REDUCED_HARDWARE) /* Entire module */ |
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/****************************************************************************** |
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* |
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* FUNCTION: acpi_get_timer_resolution |
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* |
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* PARAMETERS: resolution - Where the resolution is returned |
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* |
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* RETURN: Status and timer resolution |
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* |
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* DESCRIPTION: Obtains resolution of the ACPI PM Timer (24 or 32 bits). |
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* |
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******************************************************************************/ |
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acpi_status acpi_get_timer_resolution(u32 * resolution) |
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{ |
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ACPI_FUNCTION_TRACE(acpi_get_timer_resolution); |
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if (!resolution) { |
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return_ACPI_STATUS(AE_BAD_PARAMETER); |
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} |
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if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) { |
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*resolution = 24; |
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} else { |
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*resolution = 32; |
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} |
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return_ACPI_STATUS(AE_OK); |
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} |
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ACPI_EXPORT_SYMBOL(acpi_get_timer_resolution) |
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/****************************************************************************** |
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* |
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* FUNCTION: acpi_get_timer |
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* |
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* PARAMETERS: ticks - Where the timer value is returned |
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* |
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* RETURN: Status and current timer value (ticks) |
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* |
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* DESCRIPTION: Obtains current value of ACPI PM Timer (in ticks). |
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* |
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******************************************************************************/ |
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acpi_status acpi_get_timer(u32 * ticks) |
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{ |
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acpi_status status; |
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u64 timer_value; |
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ACPI_FUNCTION_TRACE(acpi_get_timer); |
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if (!ticks) { |
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return_ACPI_STATUS(AE_BAD_PARAMETER); |
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} |
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/* ACPI 5.0A: PM Timer is optional */ |
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if (!acpi_gbl_FADT.xpm_timer_block.address) { |
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return_ACPI_STATUS(AE_SUPPORT); |
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} |
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status = acpi_hw_read(&timer_value, &acpi_gbl_FADT.xpm_timer_block); |
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if (ACPI_SUCCESS(status)) { |
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/* ACPI PM Timer is defined to be 32 bits (PM_TMR_LEN) */ |
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*ticks = (u32)timer_value; |
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} |
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return_ACPI_STATUS(status); |
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} |
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ACPI_EXPORT_SYMBOL(acpi_get_timer) |
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/****************************************************************************** |
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* |
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* FUNCTION: acpi_get_timer_duration |
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* |
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* PARAMETERS: start_ticks - Starting timestamp |
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* end_ticks - End timestamp |
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* time_elapsed - Where the elapsed time is returned |
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* |
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* RETURN: Status and time_elapsed |
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* |
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* DESCRIPTION: Computes the time elapsed (in microseconds) between two |
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* PM Timer time stamps, taking into account the possibility of |
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* rollovers, the timer resolution, and timer frequency. |
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* |
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* The PM Timer's clock ticks at roughly 3.6 times per |
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* _microsecond_, and its clock continues through Cx state |
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* transitions (unlike many CPU timestamp counters) -- making it |
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* a versatile and accurate timer. |
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* |
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* Note that this function accommodates only a single timer |
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* rollover. Thus for 24-bit timers, this function should only |
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* be used for calculating durations less than ~4.6 seconds |
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* (~20 minutes for 32-bit timers) -- calculations below: |
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* |
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* 2**24 Ticks / 3,600,000 Ticks/Sec = 4.66 sec |
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* 2**32 Ticks / 3,600,000 Ticks/Sec = 1193 sec or 19.88 minutes |
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* |
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******************************************************************************/ |
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acpi_status |
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acpi_get_timer_duration(u32 start_ticks, u32 end_ticks, u32 *time_elapsed) |
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{ |
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acpi_status status; |
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u64 delta_ticks; |
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u64 quotient; |
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ACPI_FUNCTION_TRACE(acpi_get_timer_duration); |
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if (!time_elapsed) { |
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return_ACPI_STATUS(AE_BAD_PARAMETER); |
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} |
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/* ACPI 5.0A: PM Timer is optional */ |
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if (!acpi_gbl_FADT.xpm_timer_block.address) { |
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return_ACPI_STATUS(AE_SUPPORT); |
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} |
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if (start_ticks == end_ticks) { |
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*time_elapsed = 0; |
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return_ACPI_STATUS(AE_OK); |
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} |
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/* |
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* Compute Tick Delta: |
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* Handle (max one) timer rollovers on 24-bit versus 32-bit timers. |
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*/ |
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delta_ticks = end_ticks; |
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if (start_ticks > end_ticks) { |
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if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) { |
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/* 24-bit Timer */ |
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delta_ticks |= (u64)1 << 24; |
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} else { |
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/* 32-bit Timer */ |
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delta_ticks |= (u64)1 << 32; |
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} |
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} |
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delta_ticks -= start_ticks; |
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/* |
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* Compute Duration (Requires a 64-bit multiply and divide): |
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* |
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* time_elapsed (microseconds) = |
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* (delta_ticks * ACPI_USEC_PER_SEC) / ACPI_PM_TIMER_FREQUENCY; |
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*/ |
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status = acpi_ut_short_divide(delta_ticks * ACPI_USEC_PER_SEC, |
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ACPI_PM_TIMER_FREQUENCY, "ient, NULL); |
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*time_elapsed = (u32)quotient; |
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return_ACPI_STATUS(status); |
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} |
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ACPI_EXPORT_SYMBOL(acpi_get_timer_duration) |
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#endif /* !ACPI_REDUCED_HARDWARE */
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