| Message ID | 20181204102952.21297-3-anup@brainfault.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Provide sched_clock for riscv_timer | expand |
On Tue, 04 Dec 2018 02:29:52 PST (-0800), anup@brainfault.org wrote: > 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> > --- > drivers/clocksource/Kconfig | 2 +- > drivers/clocksource/riscv_timer.c | 9 +++++++++ > 2 files changed, 10 insertions(+), 1 deletion(-) > > diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig > index 55c77e44bb2d..19649abd7c75 100644 > --- a/drivers/clocksource/Kconfig > +++ b/drivers/clocksource/Kconfig > @@ -611,7 +611,7 @@ 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 > diff --git a/drivers/clocksource/riscv_timer.c b/drivers/clocksource/riscv_timer.c > index 084e97dc10ed..431892200a08 100644 > --- a/drivers/clocksource/riscv_timer.c > +++ b/drivers/clocksource/riscv_timer.c > @@ -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); Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index 55c77e44bb2d..19649abd7c75 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -611,7 +611,7 @@ 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 diff --git a/drivers/clocksource/riscv_timer.c b/drivers/clocksource/riscv_timer.c index 084e97dc10ed..431892200a08 100644 --- a/drivers/clocksource/riscv_timer.c +++ b/drivers/clocksource/riscv_timer.c @@ -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);
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> --- drivers/clocksource/Kconfig | 2 +- drivers/clocksource/riscv_timer.c | 9 +++++++++ 2 files changed, 10 insertions(+), 1 deletion(-)