coresight: Introduce pause and resume APIs for source

Introduce APIs for pausing and resuming trace source and export as GPL
symbols.

Signed-off-by: Leo Yan <leo.yan@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20250401180708.385396-3-leo.yan@arm.com

drivers/hwtracing/coresight/coresight-core.c

@@ -392,6 +392,28 @@ void coresight_disable_source(struct coresight_device *csdev, void *data)
 }
 EXPORT_SYMBOL_GPL(coresight_disable_source);
 
+void coresight_pause_source(struct coresight_device *csdev)
+{
+	if (!coresight_is_percpu_source(csdev))
+		return;
+
+	if (source_ops(csdev)->pause_perf)
+		source_ops(csdev)->pause_perf(csdev);
+}
+EXPORT_SYMBOL_GPL(coresight_pause_source);
+
+int coresight_resume_source(struct coresight_device *csdev)
+{
+	if (!coresight_is_percpu_source(csdev))
+		return -EOPNOTSUPP;
+
+	if (!source_ops(csdev)->resume_perf)
+		return -EOPNOTSUPP;
+
+	return source_ops(csdev)->resume_perf(csdev);
+}
+EXPORT_SYMBOL_GPL(coresight_resume_source);
+
 /*
  * coresight_disable_path_from : Disable components in the given path beyond
  * @nd in the list. If @nd is NULL, all the components, except the SOURCE are

drivers/hwtracing/coresight/coresight-priv.h

@@ -251,5 +251,7 @@ 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);
 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);
 
 #endif

include/linux/coresight.h

@@ -398,6 +398,8 @@ struct coresight_ops_link {
  *		is associated to.
  * @enable:	enables tracing for a source.
  * @disable:	disables tracing for a source.
+ * @resume_perf: resumes tracing for a source in perf session.
+ * @pause_perf:	pauses tracing for a source in perf session.
  */
 struct coresight_ops_source {
 	int (*cpu_id)(struct coresight_device *csdev);
@@ -405,6 +407,8 @@ struct coresight_ops_source {
 		      enum cs_mode mode, struct coresight_path *path);
 	void (*disable)(struct coresight_device *csdev,
 			struct perf_event *event);
+	int (*resume_perf)(struct coresight_device *csdev);
+	void (*pause_perf)(struct coresight_device *csdev);
 };
 
 /**