[PATCH 2/3] ARM: smp_scu: enable SCU standby support
Will Deacon
will.deacon at arm.com
Mon Jul 21 01:51:50 PDT 2014
On Mon, Jul 21, 2014 at 08:45:54AM +0100, Shawn Guo wrote:
> With SCU standby enabled, SCU CLK will be turned off when all processors
> are in WFI mode. And the clock will be turned on when any processor
> leaves WFI mode.
>
> This behavior should be preferable in terms of power efficiency of
> system idle. So let's set the SCU standby bit to enable the support in
> function scu_enable().
>
> Signed-off-by: Shawn Guo <shawn.guo at freescale.com>
> ---
> arch/arm/kernel/smp_scu.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/kernel/smp_scu.c b/arch/arm/kernel/smp_scu.c
> index c947508f84e6..9f29d167d02c 100644
> --- a/arch/arm/kernel/smp_scu.c
> +++ b/arch/arm/kernel/smp_scu.c
> @@ -18,6 +18,7 @@
>
> #define SCU_CTRL 0x00
> #define SCU_ENABLE (1 << 0)
> +#define SCU_STANDBY_ENABLE (1 << 5)
> #define SCU_CONFIG 0x04
> #define SCU_CPU_STATUS 0x08
> #define SCU_INVALIDATE 0x0c
> @@ -54,7 +55,7 @@ void scu_enable(void __iomem *scu_base)
> if (scu_ctrl & SCU_ENABLE)
> return;
>
> - scu_ctrl |= SCU_ENABLE;
> + scu_ctrl |= SCU_ENABLE | SCU_STANDBY_ENABLE;
I don't think this bit exists on all revisions of the A9.
Will
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