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authorDave Martin <dave.martin@linaro.org>2013-02-13 16:20:44 +0000
committerNicolas Pitre <nicolas.pitre@linaro.org>2013-09-23 18:47:31 -0400
commitd08e2e09042bd3f7ef66a35cb4bb92794ab26bb2 (patch)
treee34b0ae05a946887e11432db8f09d0110c9d6077
parent29064b88466ee725613db16d8c05b0ec5443a309 (diff)
downloadlinux-d08e2e09042bd3f7ef66a35cb4bb92794ab26bb2.tar.bz2
ARM: bL_switcher: Add query interface to discover CPU affinities
When the switcher is active, there is no straightforward way to figure out which logical CPU a given physical CPU maps to. This patch provides a function bL_switcher_get_logical_index(mpidr), which is analogous to get_logical_index(). This function returns the logical CPU on which the specified physical CPU is grouped (or -EINVAL if unknown). If the switcher is inactive or not present, -EUNATCH is returned instead. Signed-off-by: Dave Martin <dave.martin@linaro.org> Signed-off-by: Nicolas Pitre <nico@linaro.org>
-rw-r--r--arch/arm/common/bL_switcher.c20
-rw-r--r--arch/arm/include/asm/bL_switcher.h2
2 files changed, 22 insertions, 0 deletions
diff --git a/arch/arm/common/bL_switcher.c b/arch/arm/common/bL_switcher.c
index f4878a36047a..63bbc4f70564 100644
--- a/arch/arm/common/bL_switcher.c
+++ b/arch/arm/common/bL_switcher.c
@@ -532,6 +532,26 @@ static int bL_switcher_halve_cpus(void)
return 0;
}
+/* Determine the logical CPU a given physical CPU is grouped on. */
+int bL_switcher_get_logical_index(u32 mpidr)
+{
+ int cpu;
+
+ if (!bL_switcher_active)
+ return -EUNATCH;
+
+ mpidr &= MPIDR_HWID_BITMASK;
+ for_each_online_cpu(cpu) {
+ int pairing = bL_switcher_cpu_pairing[cpu];
+ if (pairing == -1)
+ continue;
+ if ((mpidr == cpu_logical_map(cpu)) ||
+ (mpidr == cpu_logical_map(pairing)))
+ return cpu;
+ }
+ return -EINVAL;
+}
+
static void bL_switcher_trace_trigger_cpu(void *__always_unused info)
{
trace_cpu_migrate_current(get_ns(), read_mpidr());
diff --git a/arch/arm/include/asm/bL_switcher.h b/arch/arm/include/asm/bL_switcher.h
index 8ada5a885c70..1714800fa113 100644
--- a/arch/arm/include/asm/bL_switcher.h
+++ b/arch/arm/include/asm/bL_switcher.h
@@ -55,6 +55,7 @@ bool bL_switcher_get_enabled(void);
void bL_switcher_put_enabled(void);
int bL_switcher_trace_trigger(void);
+int bL_switcher_get_logical_index(u32 mpidr);
#else
static inline int bL_switcher_register_notifier(struct notifier_block *nb)
@@ -70,6 +71,7 @@ static inline int bL_switcher_unregister_notifier(struct notifier_block *nb)
static inline bool bL_switcher_get_enabled(void) { return false; }
static inline void bL_switcher_put_enabled(void) { }
static inline int bL_switcher_trace_trigger(void) { return 0; }
+static inline int bL_switcher_get_logical_index(u32 mpidr) { return -EUNATCH; }
#endif /* CONFIG_BL_SWITCHER */
#endif