path: root/arch/arm/include
diff options
authorLorenzo Pieralisi <lorenzo.pieralisi@arm.com>2011-11-17 17:36:24 +0000
committerLorenzo Pieralisi <lorenzo.pieralisi@arm.com>2012-11-19 15:44:34 +0000
commit7f124aaf01439d2fa54283f3c375ce3b9fc776d4 (patch)
tree6779f47914253478511d85d7aa544b911c1f0ddc /arch/arm/include
parent5587164eea4aad88fcb79d9b21dc8f14fea598cd (diff)
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/include')
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 558d6c80aca..aaa61b6f50f 100644
--- a/arch/arm/include/asm/smp_plat.h
+++ b/arch/arm/include/asm/smp_plat.h
@@ -5,6 +5,9 @@
+#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;