[PATCH 1/3] drivers/perf: arm_pmu: Add platform hardware setup hooks.

From: Sebastian Reichel
Date: Thu Jan 18 2018 - 12:43:57 EST


Allow platform specific code to be called when enabling or
disabling the hardware.

Signed-off-by: Martin Fuzzey <mfuzzey@xxxxxxxxxxx>
Signed-off-by: Peter Senna Tschudin <peter.senna@xxxxxxxxxxxxx>
[rebased to v4.12]
Signed-off-by: Nandor Han <nandor.han@xxxxxx>
[Simplify and cleanup for upstreaming]
Signed-off-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxxxx>
---
drivers/perf/arm_pmu.c | 13 +++++++++++++
include/linux/perf/arm_pmu.h | 5 +++++
2 files changed, 18 insertions(+)

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 7bc5eee96b31..165006b9a00d 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -452,8 +452,10 @@ static int armpmu_event_init(struct perf_event *event)
static void armpmu_enable(struct pmu *pmu)
{
struct arm_pmu *armpmu = to_arm_pmu(pmu);
+ struct arm_pmu_platdata *platdata = armpmu_get_platdata(armpmu);
struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events);
int enabled = bitmap_weight(hw_events->used_mask, armpmu->num_events);
+ int err;

/* For task-bound events we may be called on other CPUs */
if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus))
@@ -461,17 +463,28 @@ static void armpmu_enable(struct pmu *pmu)

if (enabled)
armpmu->start(armpmu);
+
+ if (platdata && platdata->reserve_hardware) {
+ err = platdata->reserve_hardware(armpmu);
+ if (err)
+ dev_warn(&armpmu->plat_device->dev, "Could not reserve PMU hardware!\n");
+ }
+
}

static void armpmu_disable(struct pmu *pmu)
{
struct arm_pmu *armpmu = to_arm_pmu(pmu);
+ struct arm_pmu_platdata *platdata = armpmu_get_platdata(armpmu);

/* For task-bound events we may be called on other CPUs */
if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus))
return;

armpmu->stop(armpmu);
+
+ if (platdata && platdata->release_hardware)
+ platdata->release_hardware(armpmu);
}

/*
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index af0f44effd44..942ae9bfe971 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -17,6 +17,8 @@
#include <linux/sysfs.h>
#include <asm/cputype.h>

+struct arm_pmu;
+
/*
* struct arm_pmu_platdata - ARM PMU platform data
*
@@ -31,6 +33,8 @@
struct arm_pmu_platdata {
irqreturn_t (*handle_irq)(int irq, void *dev,
irq_handler_t pmu_handler);
+ int (*reserve_hardware)(struct arm_pmu *arm_pmu);
+ void (*release_hardware)(struct arm_pmu *arm_pmu);
unsigned long irq_flags;
};

@@ -112,6 +116,7 @@ struct arm_pmu {
int (*map_event)(struct perf_event *event);
int num_events;
u64 max_period;
+ bool reserved_hardware;
bool secure_access; /* 32-bit ARM only */
#define ARMV8_PMUV3_MAX_COMMON_EVENTS 0x40
DECLARE_BITMAP(pmceid_bitmap, ARMV8_PMUV3_MAX_COMMON_EVENTS);
--
2.15.1