diff options
| author |   Andreas Gaeer <Andreas.Gaer@baslerweb.com> | 2010-10-06 10:38:55 +0200 |
|---|---|---|
| committer |   Kevin Hilman <khilman@deeprootsystems.com> | 2010-12-10 07:33:49 -0800 |
| commit | 6d1c57c84cc474a0fa63aadaa260b13dc5c7d68b (patch) | |
| tree | 5ce151dd60a963883ff738132e30c9adf590030c /arch/arm/mach-davinci | |
| parent | Linux 2.6.37-rc5 (diff) | |
| download | linux-dev-6d1c57c84cc474a0fa63aadaa260b13dc5c7d68b.tar.xz linux-dev-6d1c57c84cc474a0fa63aadaa260b13dc5c7d68b.zip | |
davinci: Implement sched_clock()
Overwrite the default implementation of sched_clock that is based on
jiffies by something more precise. This improves timestamps in ftrace.
Implementation is copied from OMAP platform code.
Signed-off-by: Andreas Gaeer <Andreas.Gaer@baslerweb.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Diffstat (limited to 'arch/arm/mach-davinci')
| -rw-r--r-- | arch/arm/mach-davinci/time.c | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/arch/arm/mach-davinci/time.c b/arch/arm/mach-davinci/time.c index 0f21c36e65dd..5d1eea026635 100644 --- a/arch/arm/mach-davinci/time.c +++ b/arch/arm/mach-davinci/time.c @@ -272,15 +272,36 @@ static cycle_t read_cycles(struct clocksource *cs) return (cycles_t)timer32_read(t); } +/* + * Kernel assumes that sched_clock can be called early but may not have + * things ready yet. + */ +static cycle_t read_dummy(struct clocksource *cs) +{ + return 0; +} + + static struct clocksource clocksource_davinci = { .rating = 300, - .read = read_cycles, + .read = read_dummy, .mask = CLOCKSOURCE_MASK(32), .shift = 24, .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; /* + * Overwrite weak default sched_clock with something more precise + */ +unsigned long long notrace sched_clock(void) +{ + const cycle_t cyc = clocksource_davinci.read(&clocksource_davinci); + + return clocksource_cyc2ns(cyc, clocksource_davinci.mult, + clocksource_davinci.shift); +} + +/* * clockevent */ static int davinci_set_next_event(unsigned long cycles, @@ -377,6 +398,7 @@ static void __init davinci_timer_init(void) davinci_clock_tick_rate = clk_get_rate(timer_clk); /* setup clocksource */ + clocksource_davinci.read = read_cycles; clocksource_davinci.name = id_to_name[clocksource_id]; clocksource_davinci.mult = clocksource_khz2mult(davinci_clock_tick_rate/1000, |