ARM: 6071/1: perf-events: allow modules to query the number of hardware counters

For OProfile to initialise oprofilefs correctly, it needs to know
the number of counters it can represent.

This patch adds a function to the ARM perf-events backend to return
the number of hardware counters available for the current PMU.

Cc: Jamie Iles <jamie.iles@picochip.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 15 insertions, 0 deletions

diff --git a/arch/arm/include/asm/perf_event.h b/arch/arm/include/asm/perf_event.h
index fa4b32625d37..48837e6d8887 100644
--- a/arch/arm/include/asm/perf_event.h
+++ b/arch/arm/include/asm/perf_event.h
@@ -42,4 +42,7 @@ enum arm_perf_pmu_ids {
 extern enum arm_perf_pmu_ids
 armpmu_get_pmu_id(void);
 
+extern int
+armpmu_get_max_events(void);
+
 #endif /* __ARM_PERF_EVENT_H__ */
diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index 381f1211233e..c45768614c8a 100644
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -111,6 +111,18 @@ armpmu_get_pmu_id(void)
 }
 EXPORT_SYMBOL_GPL(armpmu_get_pmu_id);
 
+int
+armpmu_get_max_events(void)
+{
+        int max_events = 0;
+
+        if (armpmu != NULL)
+                max_events = armpmu->num_events;
+
+        return max_events;
+}
+EXPORT_SYMBOL_GPL(armpmu_get_max_events);
+
 #define HW_OP_UNSUPPORTED               0xFFFF
 
 #define C(_x) \