[PATCH] coresight: tpdm: add traceid_show for checking traceid

[Jie Gan]

Save the trace ID in drvdata during TPDM enablement and expose it
to userspace to support trace data parsing.

The TPDM device’s trace ID corresponds to the trace ID allocated
to the connected TPDA device.

Signed-off-by: Jie Gan <jie.gan@xxxxxxxxxxxxxxxx>
---
 drivers/hwtracing/coresight/coresight-tpdm.c | 31 +++++++++++++++++++++++++++-
 drivers/hwtracing/coresight/coresight-tpdm.h |  2 ++
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
index da77bdaad0a4..c0c9d2a7ac61 100644
--- a/drivers/hwtracing/coresight/coresight-tpdm.c
+++ b/drivers/hwtracing/coresight/coresight-tpdm.c
@@ -481,7 +481,7 @@ static void __tpdm_enable(struct tpdm_drvdata *drvdata)
 
 static int tpdm_enable(struct coresight_device *csdev, struct perf_event *event,
 		       enum cs_mode mode,
-		       __maybe_unused struct coresight_path *path)
+		       struct coresight_path *path)
 {
 	struct tpdm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
 
@@ -497,6 +497,7 @@ static int tpdm_enable(struct coresight_device *csdev, struct perf_event *event,
 	}
 
 	__tpdm_enable(drvdata);
+	drvdata->traceid = path->trace_id;
 	drvdata->enable = true;
 	spin_unlock(&drvdata->spinlock);
 
@@ -693,6 +694,26 @@ static struct attribute_group tpdm_attr_grp = {
 	.attrs = tpdm_attrs,
 };
 
+static ssize_t traceid_show(struct device *dev,
+			    struct device_attribute *attr, char *buf)
+{
+	unsigned long val;
+	struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
+
+	val = drvdata->traceid;
+	return sprintf(buf, "%#lx\n", val);
+}
+static DEVICE_ATTR_RO(traceid);
+
+static struct attribute *traceid_attrs[] = {
+	&dev_attr_traceid.attr,
+	NULL,
+};
+
+static struct attribute_group traceid_attr_grp = {
+	.attrs = traceid_attrs,
+};
+
 static ssize_t dsb_mode_show(struct device *dev,
 			     struct device_attribute *attr,
 			     char *buf)
@@ -1367,6 +1388,12 @@ static const struct attribute_group *tpdm_attr_grps[] = {
 	&tpdm_cmb_patt_grp,
 	&tpdm_cmb_msr_grp,
 	&tpdm_mcmb_attr_grp,
+	&traceid_attr_grp,
+	NULL,
+};
+
+static const struct attribute_group *static_tpdm_attr_grps[] = {
+	&traceid_attr_grp,
 	NULL,
 };
 
@@ -1425,6 +1452,8 @@ static int tpdm_probe(struct device *dev, struct resource *res)
 	desc.access = CSDEV_ACCESS_IOMEM(base);
 	if (res)
 		desc.groups = tpdm_attr_grps;
+	else
+		desc.groups = static_tpdm_attr_grps;
 	drvdata->csdev = coresight_register(&desc);
 	if (IS_ERR(drvdata->csdev))
 		return PTR_ERR(drvdata->csdev);
diff --git a/drivers/hwtracing/coresight/coresight-tpdm.h b/drivers/hwtracing/coresight/coresight-tpdm.h
index 2867f3ab8186..befecbb896f4 100644
--- a/drivers/hwtracing/coresight/coresight-tpdm.h
+++ b/drivers/hwtracing/coresight/coresight-tpdm.h
@@ -300,6 +300,7 @@ struct cmb_dataset {
  * @cmb         Specifics associated to TPDM CMB.
  * @dsb_msr_num Number of MSR supported by DSB TPDM
  * @cmb_msr_num Number of MSR supported by CMB TPDM
+ * @traceid	trace ID of the path.
  */
 
 struct tpdm_drvdata {
@@ -313,6 +314,7 @@ struct tpdm_drvdata {
 	struct cmb_dataset	*cmb;
 	u32			dsb_msr_num;
 	u32			cmb_msr_num;
+	u8			traceid;
 };
 
 /* Enumerate members of various datasets */

---
base-commit: 3f9cd19e764b782706dbaacc69e502099cb014ba
change-id: 20260306-add-traceid-show-for-tpdm-7402100afada

Best regards,
-- 
Jie Gan <jie.gan@xxxxxxxxxxxxxxxx>