From 7f124aaf01439d2fa54283f3c375ce3b9fc776d4 Mon Sep 17 00:00:00 2001 From: Lorenzo Pieralisi Date: Thu, 17 Nov 2011 17:36:24 +0000 Subject: [PATCH] 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 Acked-by: Will Deacon Acked-by: Nicolas Pitre --- arch/arm/include/asm/smp_plat.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/arch/arm/include/asm/smp_plat.h b/arch/arm/include/asm/smp_plat.h index 558d6c80aca9..aaa61b6f50ff 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 +#include + #include /* @@ -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