[U-Boot] [PATCH v4 02/14] ARM: Factor out armv7_get_cpu_id macro

[Marc Zyngier <marc.zyngier@arm.com>]

On Fri, 27 Feb 2015 13:28:01 +0000
Jan Kiszka <jan.kiszka@siemens.com> wrote:

> Handy for obtaining the ID of the current CPU. We will have more use
> cases.
> 
> CC: Marc Zyngier <marc.zyngier@arm.com>
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> ---
>  arch/arm/cpu/armv7/sunxi/psci.S | 4 ++--
>  arch/arm/include/asm/macro.h    | 7 +++++++
>  2 files changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/cpu/armv7/sunxi/psci.S
> b/arch/arm/cpu/armv7/sunxi/psci.S index 9e898f2..0523217 100644
> --- a/arch/arm/cpu/armv7/sunxi/psci.S
> +++ b/arch/arm/cpu/armv7/sunxi/psci.S
> @@ -19,6 +19,7 @@
>  
>  #include <config.h>
>  #include <asm/gic.h>
> +#include <asm/macro.h>
>  #include <asm/psci.h>
>  #include <asm/arch/cpu.h>
>  
> @@ -315,8 +316,7 @@ psci_arch_init:
>  	mcr	p15, 0, r5, c1, c1, 0	@ Write SCR
>  	isb
>  
> -	mrc	p15, 0, r4, c0, c0, 5	@ MPIDR
> -	and	r4, r4, #3		@ cpu number in cluster
> +	armv7_get_cpu_id r4
>  	mov	r5, #0x400		@ 1kB of stack per CPU
>  	mul	r4, r4, r5
>  
> diff --git a/arch/arm/include/asm/macro.h
> b/arch/arm/include/asm/macro.h index 1c8c425..0bc925a 100644
> --- a/arch/arm/include/asm/macro.h
> +++ b/arch/arm/include/asm/macro.h
> @@ -198,6 +198,13 @@ lr	.req	x30
>  .endm
>  #endif
>  
> +#else /* !CONFIG_ARM64 */
> +
> +.macro armv7_get_cpu_id rn
> +	mrc	p15, 0, \rn, c0, c0, 5	/* read MPIDR */
> +	and	\rn, \rn, #0xff		/* return CPU ID
> in cluster */
> +.endm
> +

How does this work in a multi-cluster situation? Or when you have
sparse MPIDRs?

Thanks,

	M.

>  #endif /* CONFIG_ARM64 */
>  
>  #endif /* __ASSEMBLY__ */



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