[PATCH 1/1] ARM: Add API to detect SCU base address from CP15

[Santosh Shilimkar]

On Friday 18 January 2013 04:29 PM, Hiroshi Doyu wrote:
> Add API to detect SCU base address from CP15.
>
> Signed-off-by: Hiroshi Doyu <hdoyu at nvidia.com>
> ---
> NOTE:
> This wasn't delivered to linux-arm-kernel at lists.infradead.org, resending....
>
> For usage: http://patchwork.ozlabs.org/patch/212013/
> ---
>   arch/arm/include/asm/smp_scu.h |   17 +++++++++++++++++
>   1 file changed, 17 insertions(+)
>
> diff --git a/arch/arm/include/asm/smp_scu.h b/arch/arm/include/asm/smp_scu.h
> index 4eb6d00..f619eef 100644
> --- a/arch/arm/include/asm/smp_scu.h
> +++ b/arch/arm/include/asm/smp_scu.h
> @@ -6,6 +6,23 @@
>   #define SCU_PM_POWEROFF	3
>
>   #ifndef __ASSEMBLER__
> +
> +#include <asm/cputype.h>
> +
> +static inline phys_addr_t scu_get_base(void)
> +{
> +	phys_addr_t pa;
> +	unsigned long part_number = read_cpuid_part_number();
> +
> +	switch (part_number) {
> +	case ARM_CPU_PART_CORTEX_A9:
> +		/* Get SCU physical base */
> +		asm("mrc p15, 4, %0, c15, c0, 0" : "=r" (pa));
> +		return pa;
> +	default:
> +		return 0;
> +	}
> +}
You may not need the switch case considering peripheral SCU is
specific to A9 SOCs. Would just if like below is better ?

phys_addr_t pa = 0;

if (ARM_CPU_PART_CORTEX_A9 == read_cpuid_part_number())
	asm("mrc p15, 4, %0, c15, c0, 0" : "=r" (pa));
return pa;

Regards,
Santosh