Commit 92e0d143 authored by Anup Patel's avatar Anup Patel Committed by Daniel Lezcano
Browse files

clocksource/drivers/riscv_timer: Provide the sched_clock 



Currently, we don't have a sched_clock registered for RISC-V systems.
This means Linux time keeping will use jiffies (running at HZ) as the
default sched_clock.

To avoid this, we explicity provide sched_clock using RISC-V rdtime
instruction (similar to riscv_timer clocksource).

Signed-off-by: default avatarAnup Patel <anup@brainfault.org>
Reviewed-by: default avatarPalmer Dabbelt <palmer@sifive.com>
Signed-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
parent 4f352d1f

drivers/clocksource/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -599,7 +599,7 @@ config ATCPIT100_TIMER 


config RISCV_TIMER

	bool "Timer for the RISC-V platform"

	depends on RISCV

	depends on GENERIC_SCHED_CLOCK && RISCV

	default y

	select TIMER_PROBE

	select TIMER_OF

drivers/clocksource/riscv_timer.c

+9 −0
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
#include <linux/cpu.h>

#include <linux/delay.h>

#include <linux/irq.h>

#include <linux/sched_clock.h>

#include <asm/smp.h>

#include <asm/sbi.h>
@@ -49,6 +50,11 @@ static unsigned long long riscv_clocksource_rdtime(struct clocksource *cs) 
	return get_cycles64();

}



static u64 riscv_sched_clock(void)

{

	return get_cycles64();

}



static DEFINE_PER_CPU(struct clocksource, riscv_clocksource) = {

	.name		= "riscv_clocksource",

	.rating		= 300,
@@ -97,6 +103,9 @@ static int __init riscv_timer_init_dt(struct device_node *n) 
	cs = per_cpu_ptr(&riscv_clocksource, cpuid);

	clocksource_register_hz(cs, riscv_timebase);



	sched_clock_register(riscv_sched_clock,

			BITS_PER_LONG, riscv_timebase);



	error = cpuhp_setup_state(CPUHP_AP_RISCV_TIMER_STARTING,

			 "clockevents/riscv/timer:starting",

			 riscv_timer_starting_cpu, riscv_timer_dying_cpu);

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