[PATCH 1/1] ARM: imx: Add sched_clock support to i.mx platform

[jamie@jamieiles.com (Jamie Iles)]

Hi,

On Wed, Mar 30, 2011 at 04:07:51PM +0800, Frank Li wrote:
> From: Xinyu Chen <xinyu.chen@freescale.com>
> 
> Add sched_clock() implement for i.mx platform to support nanosecond
> resolution time for sched clock used by scheduler.
> 
> Signed-off-by: Xinyu Chen <xinyu.chen@freescale.com>
> Signed-off-by: Frank Li <Frank.Li@freescale.com>
> ---
>  arch/arm/plat-mxc/time.c |    9 +++++++++
>  1 files changed, 9 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/plat-mxc/time.c b/arch/arm/plat-mxc/time.c
> index 9f0c261..de8a04f 100644
> --- a/arch/arm/plat-mxc/time.c
> +++ b/arch/arm/plat-mxc/time.c
> @@ -123,6 +123,15 @@ static struct clocksource clocksource_mxc = {
>  	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
>  };
>  
> +unsigned long long sched_clock(void)
> +{
> +	if (!timer_base)
> +		return 0;
> +
> +	return clocksource_cyc2ns(clocksource_mxc.read(&clocksource_mxc),
> +			clocksource_mxc.mult, clocksource_mxc.shift);
> +}

sched_clock() should be marked "notrace".  Also, this should use the 
sched_clock support in arch/arm/include/asm/sched_clock.h that takes 
care of wrapping and making it monotonic.

Jamie