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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: Anup Patel <anup@brainfault.org>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
This commit is contained in:
Anup Patel 2018-12-04 15:59:52 +05:30 committed by Daniel Lezcano
parent 4f352d1fc5
commit 92e0d143fd
2 changed files with 10 additions and 1 deletions
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2
drivers/clocksource/Kconfig
View File

@ -599,7 +599,7 @@ config ATCPIT100_TIMER
config RISCV_TIMER config RISCV_TIMER
bool "Timer for the RISC-V platform" bool "Timer for the RISC-V platform"
depends on RISCV depends on GENERIC_SCHED_CLOCK && RISCV
default y default y
select TIMER_PROBE select TIMER_PROBE
select TIMER_OF select TIMER_OF

9
drivers/clocksource/riscv_timer.c
View File

@ -8,6 +8,7 @@
#include <linux/cpu.h> #include <linux/cpu.h>
#include <linux/delay.h> #include <linux/delay.h>
#include <linux/irq.h> #include <linux/irq.h>
#include <linux/sched_clock.h>
#include <asm/smp.h> #include <asm/smp.h>
#include <asm/sbi.h> #include <asm/sbi.h>
@ -49,6 +50,11 @@ static unsigned long long riscv_clocksource_rdtime(struct clocksource *cs)
return get_cycles64(); return get_cycles64();
} }
static u64 riscv_sched_clock(void)
{
return get_cycles64();
}
static DEFINE_PER_CPU(struct clocksource, riscv_clocksource) = { static DEFINE_PER_CPU(struct clocksource, riscv_clocksource) = {
.name = "riscv_clocksource", .name = "riscv_clocksource",
.rating = 300, .rating = 300,
@ -97,6 +103,9 @@ static int __init riscv_timer_init_dt(struct device_node *n)
cs = per_cpu_ptr(&riscv_clocksource, cpuid); cs = per_cpu_ptr(&riscv_clocksource, cpuid);
clocksource_register_hz(cs, riscv_timebase); 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, error = cpuhp_setup_state(CPUHP_AP_RISCV_TIMER_STARTING,
"clockevents/riscv/timer:starting", "clockevents/riscv/timer:starting",
riscv_timer_starting_cpu, riscv_timer_dying_cpu); riscv_timer_starting_cpu, riscv_timer_dying_cpu);