[PATCH v2 04/12] rvtrace: Add functions to start/stop tracing on a component path

[Anup Patel]

From: Mayuresh Chitale <mchitale at ventanamicro.com>

The perf driver framework needs to be able to start / stop all components
in a trace component path during its operation. Add rvtrace_path_start()
and rvtrace_path_stop() functions for this purpose.

Co-developed-by: Anup Patel <apatel at ventanamicro.com>
Signed-off-by: Anup Patel <apatel at ventanamicro.com>
Signed-off-by: Mayuresh Chitale <mchitale at ventanamicro.com>
---
 drivers/hwtracing/rvtrace/rvtrace-core.c | 44 ++++++++++++++++++++++++
 include/linux/rvtrace.h                  |  6 ++++
 2 files changed, 50 insertions(+)

diff --git a/drivers/hwtracing/rvtrace/rvtrace-core.c b/drivers/hwtracing/rvtrace/rvtrace-core.c
index 7006a4469d62..35bd77d6880a 100644
--- a/drivers/hwtracing/rvtrace/rvtrace-core.c
+++ b/drivers/hwtracing/rvtrace/rvtrace-core.c
@@ -631,6 +631,50 @@ static void rvtrace_release_path_nodes(struct rvtrace_path *path)
 	}
 }
 
+int rvtrace_path_start(struct rvtrace_path *path)
+{
+	const struct rvtrace_driver *rtdrv;
+	struct rvtrace_component *comp;
+	struct rvtrace_path_node *node;
+	int ret;
+
+	list_for_each_entry(node, &path->comp_list, head) {
+		comp = node->comp;
+		rtdrv = to_rvtrace_driver(comp->dev.driver);
+		if (!rtdrv->start)
+			continue;
+
+		ret = rtdrv->start(comp);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(rvtrace_path_start);
+
+int rvtrace_path_stop(struct rvtrace_path *path)
+{
+	const struct rvtrace_driver *rtdrv;
+	struct rvtrace_component *comp;
+	struct rvtrace_path_node *node;
+	int ret;
+
+	list_for_each_entry(node, &path->comp_list, head) {
+		comp = node->comp;
+		rtdrv = to_rvtrace_driver(comp->dev.driver);
+		if (!rtdrv->stop)
+			continue;
+
+		ret = rtdrv->stop(comp);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(rvtrace_path_stop);
+
 struct rvtrace_path *rvtrace_create_path(struct rvtrace_component *source,
 					 struct rvtrace_component *sink,
 					 enum rvtrace_component_mode mode)
diff --git a/include/linux/rvtrace.h b/include/linux/rvtrace.h
index 4b31ab96e721..e2842e8728d4 100644
--- a/include/linux/rvtrace.h
+++ b/include/linux/rvtrace.h
@@ -274,10 +274,14 @@ struct rvtrace_path *rvtrace_create_path(struct rvtrace_component *source,
 					 struct rvtrace_component *sink,
 					 enum rvtrace_component_mode mode);
 void rvtrace_destroy_path(struct rvtrace_path *path);
+int rvtrace_path_start(struct rvtrace_path *path);
+int rvtrace_path_stop(struct rvtrace_path *path);
 
 /**
  * struct rvtrace_driver - Representation of a RISC-V trace driver
  * id_table: Table to match components handled by the driver
+ * start:        Callback to start tracing
+ * stop:         Callback to stop tracing
  * probe:        Driver probe() function
  * remove:       Driver remove() function
  * get_trace_id: Get/allocate a trace ID
@@ -286,6 +290,8 @@ void rvtrace_destroy_path(struct rvtrace_path *path);
  */
 struct rvtrace_driver {
 	const struct rvtrace_component_id *id_table;
+	int			(*start)(struct rvtrace_component *comp);
+	int			(*stop)(struct rvtrace_component *comp);
 	int			(*probe)(struct rvtrace_component *comp);
 	void			(*remove)(struct rvtrace_component *comp);
 	int			(*get_trace_id)(struct rvtrace_component *comp,
-- 
2.43.0