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

Daniel Kiss
2021-07-13T12:18:02Z

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@arm.com>
Signed-off-by: Branislav Rankov <Branislav.Rankov@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