Commit ec687ba8 authored by Jie Gan's avatar Jie Gan Committed by Suzuki K Poulose
Browse files

coresight: tpdm: add traceid_show for checking traceid 



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: default avatarJie Gan <jie.gan@oss.qualcomm.com>
Reviewed-by: default avatarJames Clark <james.clark@linaro.org>
Signed-off-by: default avatarSuzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20260331-add-traceid-show-for-tpdm-v4-1-ed3dda24a562@oss.qualcomm.com
parent ada42808

Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm

+10 −0
Original line number Diff line number Diff line
@@ -278,3 +278,13 @@ Date: Aug 2025 
KernelVersion   6.18

Contact:        Mao Jinlong <quic_jinlmao@quicinc.com>

Description:    (Read) Show hardware context information of device.



What:		/sys/bus/coresight/devices/<tpdm-name>/traceid

Date:		March 2026

KernelVersion:	7.1

Contact:	Jie Gan <jie.gan@oss.qualcomm.com>

Description:

		(R) Show the trace ID that will appear in the trace stream

		coming from this TPDM. The trace ID is inherited from the

		connected TPDA device and is fixed for the lifetime of the

		device. Returns -EINVAL if the device has not been enabled yet.

drivers/hwtracing/coresight/coresight-tpdm.c

+33 −1
Original line number Diff line number Diff line
@@ -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 +694,29 @@ 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;

	if (!val)

		return -EINVAL;



	return sysfs_emit(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 +1391,12 @@ 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 +1455,8 @@ 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);

drivers/hwtracing/coresight/coresight-tpdm.h

+2 −0
Original line number Diff line number Diff line
@@ -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 */