diff options
Diffstat (limited to 'arch/arm/plat-omap/common.c')
| -rw-r--r-- | arch/arm/plat-omap/common.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/arch/arm/plat-omap/common.c b/arch/arm/plat-omap/common.c index bf1eaf3a27d4..dddc0273bc8b 100644 --- a/arch/arm/plat-omap/common.c +++ b/arch/arm/plat-omap/common.c @@ -172,6 +172,32 @@ unsigned long long sched_clock(void) clocksource_32k.mult, clocksource_32k.shift); } +/** + * read_persistent_clock - Return time from a persistent clock. + * + * Reads the time from a source which isn't disabled during PM, the + * 32k sync timer. Convert the cycles elapsed since last read into + * nsecs and adds to a monotonically increasing timespec. + */ +static struct timespec persistent_ts; +static cycles_t cycles, last_cycles; +void read_persistent_clock(struct timespec *ts) +{ + unsigned long long nsecs; + cycles_t delta; + struct timespec *tsp = &persistent_ts; + + last_cycles = cycles; + cycles = clocksource_32k.read(&clocksource_32k); + delta = cycles - last_cycles; + + nsecs = clocksource_cyc2ns(delta, + clocksource_32k.mult, clocksource_32k.shift); + + timespec_add_ns(tsp, nsecs); + *ts = *tsp; +} + static int __init omap_init_clocksource_32k(void) { static char err[] __initdata = KERN_ERR |