[PATCH v6 08/19] coresight: Introduce coresight_enable_source() helper

[Leo Yan]

Introduce the coresight_enable_source() helper for enabling source
device, refine the comment for the imbalance between enable and disable
pair functions.

Reviewed-by: James Clark <james.clark at linaro.org>
Tested-by: James Clark <james.clark at linaro.org>
Signed-off-by: Leo Yan <leo.yan at arm.com>
---
 drivers/hwtracing/coresight/coresight-core.c     | 15 ++++++++++++---
 drivers/hwtracing/coresight/coresight-etm-perf.c |  2 +-
 drivers/hwtracing/coresight/coresight-priv.h     |  3 +++
 drivers/hwtracing/coresight/coresight-sysfs.c    |  2 +-
 4 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 6956429ca507d850c8b8c62c65de4b6fe1a1740c..8e22f0993631fa3749437175ecc984ccb1cffc13 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -437,15 +437,24 @@ static void coresight_disable_helpers(struct coresight_device *csdev,
 }
 
 /*
- * Helper function to call source_ops(csdev)->disable and also disable the
- * helpers.
+ * coresight_enable_source() only enables the source but does nothing for the
+ * associated helpers. In contrast, coresight_disable_source() calls
+ * source_ops(csdev)->disable() and also disables the helpers.
  *
  * There is an imbalance between coresight_enable_path() and
  * coresight_disable_path(). Enabling also enables the source's helpers as part
  * of the path, but disabling always skips the first item in the path (which is
  * the source), so sources and their helpers don't get disabled as part of that
- * function and we need the extra step here.
+ * function and we need the extra step in coresight_disable_source().
  */
+int coresight_enable_source(struct coresight_device *csdev,
+			    struct perf_event *event, enum cs_mode mode,
+			    struct coresight_path *path)
+{
+	return source_ops(csdev)->enable(csdev, event, mode, path);
+}
+EXPORT_SYMBOL_GPL(coresight_enable_source);
+
 void coresight_disable_source(struct coresight_device *csdev, void *data)
 {
 	source_ops(csdev)->disable(csdev, data);
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index f85dedf89a3f9e85d568ca4c320fa6fa6d9059ff..11c529fd4f3df973e5be9de2a7686163c1abceca 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -533,7 +533,7 @@ static void etm_event_start(struct perf_event *event, int flags)
 		goto fail_end_stop;
 
 	/* Finally enable the tracer */
-	if (source_ops(csdev)->enable(csdev, event, CS_MODE_PERF, path))
+	if (coresight_enable_source(csdev, event, CS_MODE_PERF, path))
 		goto fail_disable_path;
 
 	/*
diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
index 1ea882dffd703b2873e41b4ce0c2564d2ce9bbad..22fb6c5bffbf714bdbe2f4dcbfe66e453c2d1f4f 100644
--- a/drivers/hwtracing/coresight/coresight-priv.h
+++ b/drivers/hwtracing/coresight/coresight-priv.h
@@ -248,6 +248,9 @@ void coresight_add_helper(struct coresight_device *csdev,
 
 void coresight_set_percpu_sink(int cpu, struct coresight_device *csdev);
 struct coresight_device *coresight_get_percpu_sink(int cpu);
+int coresight_enable_source(struct coresight_device *csdev,
+			    struct perf_event *event, enum cs_mode mode,
+			    struct coresight_path *path);
 void coresight_disable_source(struct coresight_device *csdev, void *data);
 void coresight_pause_source(struct coresight_device *csdev);
 int coresight_resume_source(struct coresight_device *csdev);
diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c b/drivers/hwtracing/coresight/coresight-sysfs.c
index 7c7d3a3cb9f18a9dfa78eb5c19dda43fa6656271..cb1d4f90a9c245b2c2f6e818c0f4d905b86477db 100644
--- a/drivers/hwtracing/coresight/coresight-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-sysfs.c
@@ -66,7 +66,7 @@ static int coresight_enable_source_sysfs(struct coresight_device *csdev,
 	 */
 	lockdep_assert_held(&coresight_mutex);
 	if (coresight_get_mode(csdev) != CS_MODE_SYSFS) {
-		ret = source_ops(csdev)->enable(csdev, NULL, mode, path);
+		ret = coresight_enable_source(csdev, NULL, mode, path);
 		if (ret)
 			return ret;
 	}

-- 
2.34.1