# Kconfig - timer driver configuration options # # Copyright (c) 2014-2015 Wind River Systems, Inc. # Copyright (c) 2016 Cadence Design Systems, Inc. # # SPDX-License-Identifier: Apache-2.0 # menu "Timer Drivers" config HPET_TIMER bool "HPET timer" depends on X86 select IOAPIC select LOAPIC select TIMER_READS_ITS_FREQUENCY_AT_RUNTIME select TICKLESS_CAPABLE help This option selects High Precision Event Timer (HPET) as a system timer. config HPET_TIMER_LEGACY_EMULATION bool "HPET timer legacy emulation mode" depends on HPET_TIMER help This option switches HPET to legacy emulation mode. In this mode 8254 PIT is disabled, HPET timer0 is connected to IOAPIC IRQ2, timer1 -- to IOAPIC IRQ8. config HPET_TIMER_DEBUG bool "Enable HPET debug output" depends on HPET_TIMER && PRINTK help This option enables HPET debugging output. config HPET_TIMER_BASE_ADDRESS hex "HPET Base Address" default 0xFED00000 depends on HPET_TIMER help This options specifies the base address of the HPET timer device. config HPET_TIMER_IRQ int "HPET Timer IRQ" default 20 depends on HPET_TIMER help This option specifies the IRQ used by the HPET timer. config HPET_TIMER_IRQ_PRIORITY int "HPET Timer IRQ Priority" default 4 depends on HPET_TIMER help This option specifies the IRQ priority used by the HPET timer. choice depends on HPET_TIMER prompt "HPET Interrupt Trigger Condition" default HPET_TIMER_FALLING_EDGE config HPET_TIMER_FALLING_EDGE bool "Falling Edge" help This option signifies that the HPET timer uses falling edge interrupts. config HPET_TIMER_RISING_EDGE bool "Rising Edge" help This option signifies that the HPET timer uses rising edge interrupts. config HPET_TIMER_LEVEL_HIGH bool "Level High" help This option signifies that the HPET timer uses level high interrupts. config HPET_TIMER_LEVEL_LOW bool "Level Low" help This option signifies that the HPET timer uses level low interrupts. endchoice config LOAPIC_TIMER bool "LOAPIC timer" depends on (LOAPIC || MVIC) && X86 help This option selects LOAPIC timer as a system timer. config LOAPIC_TIMER_IRQ int "Local APIC Timer IRQ" default 24 depends on LOAPIC_TIMER help This option specifies the IRQ used by the LOAPIC timer. config LOAPIC_TIMER_IRQ_PRIORITY int "Local APIC Timer IRQ Priority" default 2 depends on LOAPIC_TIMER help This options specifies the IRQ priority used by the LOAPIC timer. config TSC_CYCLES_PER_SEC int "Frequency of x86 CPU timestamp counter" default 0 depends on LOAPIC_TIMER help The x86 implementation of LOAPIC k_cycle_get_32() relies on the x86 TSC. This runs at the CPU speed and not the bus speed. If set to 0, the value of CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC will be used instead; many MCUs these values are the same. config ARCV2_TIMER bool "ARC Timer" default y depends on ARC select TICKLESS_CAPABLE help This module implements a kernel device driver for the ARCv2 processor timer 0 and provides the standard "system clock driver" interfaces. config ARCV2_TIMER_IRQ_PRIORITY int "ARC timer interrupt priority" default 0 depends on ARCV2_TIMER help This option specifies the IRQ priority used by the ARC timer. Lower values have higher priority. config CORTEX_M_SYSTICK bool "Cortex-M SYSTICK timer" default y depends on CPU_HAS_SYSTICK select TICKLESS_CAPABLE help This module implements a kernel device driver for the Cortex-M processor SYSTICK timer and provides the standard "system clock driver" interfaces. config ALTERA_AVALON_TIMER bool "Altera Avalon Interval Timer" default y depends on NIOS2 help This module implements a kernel device driver for the Altera Avalon Interval Timer as described in the Embedded IP documentation, for use with Nios II and possibly other Altera soft CPUs. It provides the standard "system clock driver" interfaces. config NRF_RTC_TIMER bool "nRF Real Time Counter (NRF_RTC1) Timer" default y depends on CLOCK_CONTROL_NRF5 select TICKLESS_CAPABLE help This module implements a kernel device driver for the nRF Real Time Counter NRF_RTC1 and provides the standard "system clock driver" interfaces. config PULPINO_TIMER bool "pulpino Timer" default y depends on SOC_RISCV32_PULPINO help This module implements a kernel device driver for the pulpino processor timer driver. It provides the standard "system clock driver" interfaces. config RISCV_MACHINE_TIMER bool "RISCV Machine Timer" depends on SOC_FAMILY_RISCV_PRIVILEGE select TICKLESS_CAPABLE help This module implements a kernel device driver for the generic RISCV machine timer driver. It provides the standard "system clock driver" interfaces. config NATIVE_POSIX_TIMER bool "(POSIX) native_posix timer driver" default y depends on BOARD_NATIVE_POSIX help This module implements a kernel device driver for the native_posix HW timer model config XTENSA_TIMER bool "Xtensa timer support" depends on XTENSA default y select TICKLESS_CAPABLE help Enables a system timer driver for Xtensa based on the CCOUNT and CCOMPARE special registers. config XTENSA_TIMER_ID int "System timer CCOMPAREn register index" default 1 depends on XTENSA_TIMER help Index of the CCOMPARE register (and associated interrupt) used for the system timer. Xtensa CPUs have hard-configured interrupt priorities associated with each timer, and some of them can be unmaskable (and thus not usable by OS code that need synchronization, like the timer subsystem!). Choose carefully. Generally you want the timer with the highest priority maskable interrupt. config SYSTEM_CLOCK_DISABLE bool "API to disable system clock" help This option enables the sys_clock_disable() API in the kernel. It is needed by some subsystems (which will automatically select it), but is rarely needed by applications. config TIMER_READS_ITS_FREQUENCY_AT_RUNTIME bool "Timer queries its hardware to find its frequency at runtime" help The drivers select this option automatically when needed. Do not modify this unless you have a very good reason for it. config SYSTEM_CLOCK_INIT_PRIORITY int "System clock driver initialization priority" default 0 help This options can be used to set a specific initialization priority value for the system clock driver. As driver initialization might need the clock to be running already, you should let the default value as it is (0). config TICKLESS_CAPABLE bool "Timer driver supports tickless operation" help Timer drivers should select this flag if they are capable of supporting tickless operation. That is, a call to z_clock_set_timeout() with a number of ticks greater than one should be expected not to produce a call to z_clock_announce() (really, not to produce an interrupt at all) until the specified expiration. config QEMU_TICKLESS_WORKAROUND bool "Disable tickless on qemu due to asynchrony bug" depends on QEMU_TARGET && TICKLESS_KERNEL help Qemu (without -icount) has trouble keeping time when the host process needs to timeshare. The host OS will routinely schedule out a process at timescales equivalent to the guest tick rate. With traditional ticks delivered regularly by the hardware, that's mostly OK as it looks like a late interrupt. But in tickless mode, the driver needs some CPU in order to schedule the tick in the first place. If that gets delayed across a tick boundary, time gets wonky. This tunable is a hint to the driver to disable tickless accounting on qemu. Use it only on tests that are known to have problems. endmenu