[PATCHv2 02/12] arm64: smp_plat: add get_logical_index

[Catalin Marinas]

On Mon, May 18, 2015 at 11:38:13AM +0100, Mark Rutland wrote:
> The PSCI MIGRATE_INFO_UP_CPU call returns a physical ID, which we will
> need to map back to a Linux logical ID.
> 
> Implement a reusable get_logical_index to map from a physical ID to a
> logical ID.
> 
> Signed-off-by: Mark Rutland <mark.rutland at arm.com>
> Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi at arm.com>
> Cc: Catalin Marinas <catalin.marinas at arm.com>
> Cc: Will Deacon <will.deacon at arm.com>
> ---
>  arch/arm64/include/asm/smp_plat.h | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/arch/arm64/include/asm/smp_plat.h b/arch/arm64/include/asm/smp_plat.h
> index 8dcd61e..7abf757 100644
> --- a/arch/arm64/include/asm/smp_plat.h
> +++ b/arch/arm64/include/asm/smp_plat.h
> @@ -19,6 +19,8 @@
>  #ifndef __ASM_SMP_PLAT_H
>  #define __ASM_SMP_PLAT_H
>  
> +#include <linux/cpumask.h>
> +
>  #include <asm/types.h>
>  
>  struct mpidr_hash {
> @@ -39,6 +41,20 @@ static inline u32 mpidr_hash_size(void)
>   */
>  extern u64 __cpu_logical_map[NR_CPUS];
>  #define cpu_logical_map(cpu)    __cpu_logical_map[cpu]
> +/*
> + * Retrieve logical cpu index corresponding to a given MPIDR.Aff*
> + *  - mpidr: MPIDR.Aff* bits to be used for the look-up
> + *
> + * Returns the cpu logical index or -EINVAL on look-up error
> + */
> +static inline int get_logical_index(u64 mpidr)
> +{
> +	int cpu;
> +	for (cpu = 0; cpu < nr_cpu_ids; cpu++)
> +		if (cpu_logical_map(cpu) == mpidr)
> +			return cpu;
> +	return -EINVAL;
> +}

Do we guarantee that mpidr here only contains the affinity bits (i.e. no
masking)? If yes:

Acked-by: Catalin Marinas <catalin.marinas at arm.com>