// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 /****************************************************************************** * * Name: hwtimer.c - ACPI Power Management Timer Interface * * Copyright (C) 2000 - 2022, 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 */