On 11/12/2025 06:10, Jie Gan wrote:

Retrieving the helper device of the specific coresight device based on its helper_subtype because a single coresight device may has multiple types of the helper devices.

Reviewed-by: Mike Leach mike.leach@linaro.org Signed-off-by: Jie Gan jie.gan@oss.qualcomm.com

---

drivers/hwtracing/coresight/coresight-core.c | 35 ++++++++++++++++++++++++++++ drivers/hwtracing/coresight/coresight-priv.h | 2 ++ 2 files changed, 37 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c index 0e8448784c62..667883ccb4b7 100644 --- a/drivers/hwtracing/coresight/coresight-core.c +++ b/drivers/hwtracing/coresight/coresight-core.c @@ -585,6 +585,41 @@ struct coresight_device *coresight_get_sink(struct coresight_path *path) } EXPORT_SYMBOL_GPL(coresight_get_sink); +/**

• • coresight_get_helper: find the helper device of the assigned csdev.
• • @csdev: The csdev the helper device is conntected to.
• • @type: helper_subtype of the expected helper device.
• • Retrieve the helper device for the specific csdev based on its
• • helper_subtype.
• • Return: the helper's csdev upon success or NULL for fail.
• */

+struct coresight_device *coresight_get_helper(struct coresight_device *csdev,

• 			      enum coresight_dev_subtype_helper subtype)
  

We have almost a similar function in coresight-core.c :

coresight_find_output_type(pdata, type, subtype).

Please could we reuse that, instead of adding similar funcitons ?

Please be careful about the mutex.

Suzuki

+{

• int i;
• struct coresight_device *helper;
• /* protect the connections */
• mutex_lock(&coresight_mutex);
• for (i = 0; i < csdev->pdata->nr_outconns; ++i) {

• helper = csdev->pdata->out_conns[i]->dest_dev;
  

• if (!helper || !coresight_is_helper(helper))
  

• 	continue;
  

• if (helper->subtype.helper_subtype == subtype) {
  

• 	mutex_unlock(&coresight_mutex);
  

• 	return helper;
  

• }
  

• }
• mutex_unlock(&coresight_mutex);
• return NULL;

+} +EXPORT_SYMBOL_GPL(coresight_get_helper);

• /**
  • coresight_get_in_port: Find the input port number at @csdev where a @remote
  • device is connected to.

diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h index cbf80b83e5ce..8e39a4dc7256 100644 --- a/drivers/hwtracing/coresight/coresight-priv.h +++ b/drivers/hwtracing/coresight/coresight-priv.h @@ -157,6 +157,8 @@ void coresight_path_assign_trace_id(struct coresight_path *path, enum cs_mode mode); int coresight_get_in_port(struct coresight_device *csdev, struct coresight_device *remote); +struct coresight_device *coresight_get_helper(struct coresight_device *csdev,

• 			      enum coresight_dev_subtype_helper subtype);
  

#if IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM3X) int etm_readl_cp14(u32 off, unsigned int *val);