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# Copyright (c) 2014-2015 Wind River Systems, Inc.
# Copyright (c) 2016 Cadence Design Systems, Inc.
# Copyright (c) 2019 Intel Corp.
# SPDX-License-Identifier: Apache-2.0
config RISCV_MACHINE_TIMER
bool "RISCV Machine Timer"
default y
depends on DT_HAS_ANDESTECH_MACHINE_TIMER_ENABLED || \
DT_HAS_NEORV32_MACHINE_TIMER_ENABLED || \
DT_HAS_NUCLEI_SYSTIMER_ENABLED || \
DT_HAS_SIFIVE_CLINT0_ENABLED || \
DT_HAS_TELINK_MACHINE_TIMER_ENABLED
select TICKLESS_CAPABLE
select TIMER_HAS_64BIT_CYCLE_COUNTER
help
This module implements a kernel device driver for the generic RISCV machine
timer driver. It provides the standard "system clock driver" interfaces.
config RISCV_MACHINE_TIMER_SYSTEM_CLOCK_DIVIDER
int
default 0
help
Specifies the division ratio of the system clock supplied to the Machine Timer.
A clock obtained by dividing the system clock by a value of [2^N] is
supplied to the timer. Where N is this parameter's value.
When N=2, it is divided by 4, and when N=5, it is divided by 32.
Default case is N=0, this means use system clock as machine timer clock.
It is normal configuration for RISC-V machine clock.
This parameter usually depends on the hardware configuration.
The division ratio should define in devicetree,
and it is desirable usage that references it with using a function such as
dt_node_int_prop_int from Kconfig. (Tune in the conf file is not preferable.)
config RISCV_MACHINE_TIMER_MIN_DELAY
int
default 100
help
Specifies the minimum number of machine cycles before the RISC-V machine
time compare register is allowed to be updated by the RISC-V machine timer
driver.