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Commit 67948ada authored by Stanislav Meduna's avatar Stanislav Meduna Committed by Shawn Guo
Browse files

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: default avatarStanislav Meduna <stano@meduna.org>
Signed-off-by: default avatarShawn Guo <shawn.guo@linaro.org>
parent 24196d5c

arch/arm/mach-mxs/timer.c

+9 −1
Original line number Diff line number Diff line
@@ -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;

}