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| author | Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> | 2011-11-17 17:36:24 (GMT) |
|---|---|---|
| committer | Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> | 2012-11-19 15:44:34 (GMT) |
| commit | 7f124aaf01439d2fa54283f3c375ce3b9fc776d4 (patch) | |
| tree | 6779f47914253478511d85d7aa544b911c1f0ddc /arch/arm | |
| parent | 5587164eea4aad88fcb79d9b21dc8f14fea598cd (diff) | |
| download | linux-fsl-qoriq-7f124aaf01439d2fa54283f3c375ce3b9fc776d4.tar.xz | |
ARM: kernel: add logical mappings look-up
In ARM SMP systems the MPIDR register ([23:0] bits) is used to uniquely
identify CPUs.
In order to retrieve the logical CPU index corresponding to a given
MPIDR value and guarantee a consistent translation throughout the kernel,
this patch adds a look-up based on the MPIDR[23:0] so that kernel subsystems
can use it whenever the logical cpu index corresponding to a given MPIDR
value is needed.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/include/asm/smp_plat.h | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/arch/arm/include/asm/smp_plat.h b/arch/arm/include/asm/smp_plat.h index 558d6c8..aaa61b6 100644 --- a/arch/arm/include/asm/smp_plat.h +++ b/arch/arm/include/asm/smp_plat.h @@ -5,6 +5,9 @@ #ifndef __ASMARM_SMP_PLAT_H #define __ASMARM_SMP_PLAT_H +#include <linux/cpumask.h> +#include <linux/err.h> + #include <asm/cputype.h> /* @@ -48,5 +51,19 @@ static inline int cache_ops_need_broadcast(void) */ extern int __cpu_logical_map[]; #define cpu_logical_map(cpu) __cpu_logical_map[cpu] +/* + * Retrieve logical cpu index corresponding to a given MPIDR[23:0] + * - mpidr: MPIDR[23:0] to be used for the look-up + * + * Returns the cpu logical index or -EINVAL on look-up error + */ +static inline int get_logical_index(u32 mpidr) +{ + int cpu; + for (cpu = 0; cpu < nr_cpu_ids; cpu++) + if (cpu_logical_map(cpu) == mpidr) + return cpu; + return -EINVAL; +} #endif |