[PATCH 4/4] perf: nvidia_t410_c2c: handle PERF_EF_UPDATE in stop

[Saurav Sachidanand]

nv_c2c_pmu_stop() does not read the final counter value when called
with PERF_EF_UPDATE. The last counter delta is lost when perf core
removes the event.

Add the standard PMU stop pattern: bail out if already stopped, call
nv_c2c_pmu_event_update() when PERF_EF_UPDATE is requested, then mark
the event stopped.

Fixes: 2f89b7f78c50 ("perf: add NVIDIA Tegra410 C2C PMU")
Signed-off-by: Saurav Sachidanand <sauravsc@xxxxxxxxxx>
---
 drivers/perf/nvidia_t410_c2c_pmu.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/perf/nvidia_t410_c2c_pmu.c b/drivers/perf/nvidia_t410_c2c_pmu.c
index 662fa1bc833a5..39d0e661e4c5c 100644
--- a/drivers/perf/nvidia_t410_c2c_pmu.c
+++ b/drivers/perf/nvidia_t410_c2c_pmu.c
@@ -394,6 +394,12 @@ static void nv_c2c_pmu_start(struct perf_event *event, int pmu_flags)
 
 static void nv_c2c_pmu_stop(struct perf_event *event, int pmu_flags)
 {
+	if (event->hw.state & PERF_HES_STOPPED)
+		return;
+
+	if (pmu_flags & PERF_EF_UPDATE)
+		nv_c2c_pmu_event_update(event);
+
 	event->hw.state |= PERF_HES_STOPPED;
 }
 
-- 
2.47.3