diff options
| author | Marc Zyngier <marc.zyngier@arm.com> | 2011-01-14 15:32:36 +0000 |
|---|---|---|
| committer | Marc Zyngier <marc.zyngier@arm.com> | 2012-04-20 14:55:09 +0100 |
| commit | cb50ff7cceecd998e864167b1dcaddc3aa05e18a (patch) | |
| tree | 331673bf9bd2636ce351cddb91a3300132d93bd9 | |
| parent | 97926c194bc6d0c55ca5119ba38ba69bc9006ffb (diff) | |
ARM: architected timers: Add A15 specific sched_clock implementation
Provide an A15 sched_clock implementation using the virtual counter,
which is thought to be more useful than the physical one in a
virtualised environment, as it can offset the time spent in another
VM or the hypervisor.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
| -rw-r--r-- | arch/arm/include/asm/arch_timer.h | 6 | ||||
| -rw-r--r-- | arch/arm/kernel/arch_timer.c | 25 |
2 files changed, 31 insertions, 0 deletions
diff --git a/arch/arm/include/asm/arch_timer.h b/arch/arm/include/asm/arch_timer.h index 827305d77b3e..dc008c696b5a 100644 --- a/arch/arm/include/asm/arch_timer.h +++ b/arch/arm/include/asm/arch_timer.h @@ -9,11 +9,17 @@ struct arch_timer { #ifdef CONFIG_ARM_ARCH_TIMER int arch_timer_register(struct arch_timer *); +int arch_timer_sched_clock_init(void); #else static inline int arch_timer_register(struct arch_timer *at) { return -ENXIO; } + +static inline int arch_timer_sched_clock_init(void) +{ + return -ENXIO; +} #endif #endif diff --git a/arch/arm/kernel/arch_timer.c b/arch/arm/kernel/arch_timer.c index ce8c7eda31c2..611859a2d901 100644 --- a/arch/arm/kernel/arch_timer.c +++ b/arch/arm/kernel/arch_timer.c @@ -22,6 +22,7 @@ #include <asm/cputype.h> #include <asm/localtimer.h> #include <asm/arch_timer.h> +#include <asm/sched_clock.h> static unsigned long arch_timer_rate; static int arch_timer_ppi; @@ -203,6 +204,18 @@ static inline cycle_t arch_counter_get_cntvct(void) return ((cycle_t) cvalh << 32) | cvall; } +static u32 notrace arch_counter_get_cntvct32(void) +{ + cycle_t cntvct = arch_counter_get_cntvct(); + + /* + * The sched_clock infrastructure only knows about counters + * with at most 32bits. Forget about the upper 24 bits for the + * time being... + */ + return (u32)(cntvct & (u32)~0); +} + static cycle_t arch_counter_read(struct clocksource *cs) { return arch_counter_get_cntpct(); @@ -285,3 +298,15 @@ out_free: return err; } + +int __init arch_timer_sched_clock_init(void) +{ + int err; + + err = arch_timer_available(); + if (err) + return err; + + setup_sched_clock(arch_counter_get_cntvct32, 32, arch_timer_rate); + return 0; +} |