On Fri, 27 Feb 2015 13:28:01 +0000
Jan Kiszka <jan.kis...@siemens.com> wrote:
> Handy for obtaining the ID of the current CPU. We will have more use
> cases.
>
> CC: Marc Zyngier <marc.zyng...@arm.com>
> Signed-off-by: Jan Kiszka <jan.kis...@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__ */
--
Jazz is not dead. It just smells funny.
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