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authorStanislav Meduna <stano@meduna.org>2012-11-09 02:39:14 +0400
committerShawn Guo <shawn.guo@linaro.org>2012-11-12 05:27:30 +0400
commit67948adad178a041cd545c3f9b2bd077b1c5d7a1 (patch)
tree6511c3bd9c432b40d2b398b1a72663fced360cbf /arch/arm/mach-mxs
parent24196d5c597272b1e5c57903f2e3c7996e607117 (diff)
downloadlinux-67948adad178a041cd545c3f9b2bd077b1c5d7a1.tar.xz
ARM: mxs: Setup scheduler clock
Setup scheduler clock on ARM MXS platforms with a 32-bit timrot such as i.MX28. This allows the scheduler to use sub-jiffy resolution. The corresponding change for 16-bit v1 timrots is not possible at the moment due to rounding issues with clock values wrapping faster than once per several seconds in the common ARM platform code. Signed-off-by: Stanislav Meduna <stano@meduna.org> Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Diffstat (limited to 'arch/arm/mach-mxs')
-rw-r--r--arch/arm/mach-mxs/timer.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/arch/arm/mach-mxs/timer.c b/arch/arm/mach-mxs/timer.c
index 7c3792613392..856f4c796061 100644
--- a/arch/arm/mach-mxs/timer.c
+++ b/arch/arm/mach-mxs/timer.c
@@ -29,6 +29,7 @@
#include <linux/of_irq.h>
#include <asm/mach/time.h>
+#include <asm/sched_clock.h>
#include <mach/mxs.h>
#include <mach/common.h>
@@ -233,15 +234,22 @@ static struct clocksource clocksource_mxs = {
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
+static u32 notrace mxs_read_sched_clock_v2(void)
+{
+ return ~readl_relaxed(mxs_timrot_base + HW_TIMROT_RUNNING_COUNTn(1));
+}
+
static int __init mxs_clocksource_init(struct clk *timer_clk)
{
unsigned int c = clk_get_rate(timer_clk);
if (timrot_is_v1())
clocksource_register_hz(&clocksource_mxs, c);
- else
+ else {
clocksource_mmio_init(mxs_timrot_base + HW_TIMROT_RUNNING_COUNTn(1),
"mxs_timer", c, 200, 32, clocksource_mmio_readl_down);
+ setup_sched_clock(mxs_read_sched_clock_v2, 32, c);
+ }
return 0;
}