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

From: Anup Patel <apatel@ventanamicro.com>
To: Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Greg KH <gregkh@linuxfoundation.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
	devicetree@vger.kernel.org, Alexandre Ghiti <alex@ghiti.fr>,
	Atish Patra <atish.patra@linux.dev>,
	Peter Zijlstra <peterz@infradead.org>,
	Anup Patel <anup@brainfault.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	linux-kernel@vger.kernel.org,
	Mayuresh Chitale <mchitale@ventanamicro.com>,
	Ingo Molnar <mingo@redhat.com>, Jiri Olsa <jolsa@kernel.org>,
	Anup Patel <apatel@ventanamicro.com>,
	Mayuresh Chitale <mchitale@gmail.com>,
	Namhyung Kim <namhyung@kernel.org>,
	linux-riscv@lists.infradead.org,
	Andrew Jones <ajones@ventanamicro.com>,
	Liang Kan <kan.liang@linux.intel.com>
Subject: [PATCH v2 04/12] rvtrace: Add functions to start/stop tracing on a component path
Date: Sat,  1 Nov 2025 21:12:37 +0530	[thread overview]
Message-ID: <20251101154245.162492-5-apatel@ventanamicro.com> (raw)
In-Reply-To: <20251101154245.162492-1-apatel@ventanamicro.com>

From: Mayuresh Chitale <mchitale@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@ventanamicro.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Mayuresh Chitale <mchitale@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


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