From: Leo Yan <leo.yan@arm.com>
Date: Fri, 15 May 2026 20:08:25 +0000 (+0100)
Subject: coresight: Introduce coresight_enable_source() helper
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=a18e877b0491ad21b24d6f1fe2afb854990e031d;p=thirdparty%2Flinux.git

coresight: Introduce coresight_enable_source() helper

Introduce the coresight_enable_source() helper for enabling source
device.

Add validation to ensure the device is a source before proceeding with
further operations.

Reviewed-by: James Clark <james.clark@linaro.org>
Tested-by: James Clark <james.clark@linaro.org>
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Tested-by: Jie Gan <jie.gan@oss.qualcomm.com>
Signed-off-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20260515-arm_coresight_path_power_management_improvement-v14-18-f88c4a3ecfe9@arm.com
---

diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 61ae7b6c7a836..f833b73ebc168 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -479,11 +479,25 @@ static void coresight_disable_helpers(struct coresight_device *csdev,
 }
 
 /*
- * coresight_disable_source() only disables the source, but do nothing for
- * the associated helpers, which are controlled as part of the path.
+ * coresight_enable_source() and coresight_disable_source() only enable and
+ * disable the source, but do nothing for the associated helpers, which are
+ * controlled as part of the path.
  */
+int coresight_enable_source(struct coresight_device *csdev,
+			    struct perf_event *event, enum cs_mode mode,
+			    struct coresight_path *path)
+{
+	if (!coresight_is_device_source(csdev))
+		return -EINVAL;
+
+	return source_ops(csdev)->enable(csdev, event, mode, path);
+}
+
 void coresight_disable_source(struct coresight_device *csdev, void *data)
 {
+	if (!coresight_is_device_source(csdev))
+		return;
+
 	source_ops(csdev)->disable(csdev, data);
 }
 EXPORT_SYMBOL_GPL(coresight_disable_source);
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index 89b99c3caedbc..09b21a711a876 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -593,7 +593,7 @@ static void etm_event_start(struct perf_event *event, int flags)
 		goto fail_end_stop;
 
 	/* Finally enable the tracer */
-	if (source_ops(source)->enable(source, event, CS_MODE_PERF, path))
+	if (coresight_enable_source(source, 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 808d1546f5682..dddac946659fc 100644
--- a/drivers/hwtracing/coresight/coresight-priv.h
+++ b/drivers/hwtracing/coresight/coresight-priv.h
@@ -251,6 +251,9 @@ struct coresight_device *coresight_get_percpu_sink(int cpu);
 struct coresight_device *coresight_get_source(struct coresight_path *path);
 struct coresight_device *coresight_get_percpu_source_ref(int cpu);
 void coresight_put_percpu_source_ref(struct coresight_device *csdev);
+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 682500b7296c2..9ec112b457bbd 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;
 	}