[PATCHv2 2/4] coresight: tmc-etr: Track perf handler.

[Daniel Kiss]

Keep track of the perf handler that is registred by the first tracer.
This will be used by the update call from polling.

Signed-off-by: Daniel Kiss <daniel.kiss at arm.com>
Signed-off-by: Branislav Rankov <Branislav.Rankov at arm.com>
---
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 6 ++++--
 drivers/hwtracing/coresight/coresight-tmc.h     | 2 ++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 589bb2d56e802..55c9b5fd9f832 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -1503,8 +1503,8 @@ tmc_update_etr_buffer(struct coresight_device *csdev,
 
 	spin_lock_irqsave(&drvdata->spinlock, flags);
 
-	/* Don't do anything if another tracer is using this sink */
-	if (atomic_read(csdev->refcnt) != 1) {
+	/* Serve only the tracer with the leading perf handler */
+	if (drvdata->perf_handle != handle) {
 		spin_unlock_irqrestore(&drvdata->spinlock, flags);
 		goto out;
 	}
@@ -1619,6 +1619,7 @@ static int tmc_enable_etr_sink_perf(struct coresight_device *csdev, void *data)
 		drvdata->pid = pid;
 		drvdata->mode = CS_MODE_PERF;
 		drvdata->perf_buf = etr_perf->etr_buf;
+		drvdata->perf_handle = handle;
 		atomic_inc(csdev->refcnt);
 	}
 
@@ -1666,6 +1667,7 @@ static int tmc_disable_etr_sink(struct coresight_device *csdev)
 	drvdata->mode = CS_MODE_DISABLED;
 	/* Reset perf specific data */
 	drvdata->perf_buf = NULL;
+	drvdata->perf_handle = NULL;
 
 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index b91ec7dde7bc9..81583ffb973dc 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -184,6 +184,7 @@ struct etr_buf {
  * @idr_mutex:	Access serialisation for idr.
  * @sysfs_buf:	SYSFS buffer for ETR.
  * @perf_buf:	PERF buffer for ETR.
+ * @perf_handle: PERF handle for ETR.
  */
 struct tmc_drvdata {
 	void __iomem		*base;
@@ -207,6 +208,7 @@ struct tmc_drvdata {
 	struct mutex		idr_mutex;
 	struct etr_buf		*sysfs_buf;
 	struct etr_buf		*perf_buf;
+	struct perf_output_handle *perf_handle;
 };
 
 struct etr_buf_operations {
-- 
2.25.1