On 2015-02-28 14:56, Marc Zyngier wrote: > 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?
I have no idea. That masking was stolen from your code. The model we assume for PSCI is that there is no cluster and that we have enough per-cpu space for up to the maximum cpu ID obtained that way. If you are concerned about signaling a false general applicability of that macro, I can fold it back into the callers or add some comments about restrictions. My plan was just to make the caller site a bit more readable. Jan -- Siemens AG, Corporate Technology, CT RTC ITP SES-DE Corporate Competence Center Embedded Linux _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
