Adds in sysfs links for connections where the connected device is another
coresight device. This allows examination of the coresight topology.

Non-coresight connections remain just as a reference name.

Signed-off-by: Mike Leach <redacted>
---
 drivers/hwtracing/coresight/coresight-cti.c | 41 ++++++++++++++++++++-
 1 file changed, 40 insertions(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-cti.c b/drivers/hwtracing/coresight/coresight-cti.c
index 9e18e176831c..f620e9460e7d 100644
--- a/drivers/hwtracing/coresight/coresight-cti.c
+++ b/drivers/hwtracing/coresight/coresight-cti.c

@@ -441,6 +441,37 @@ int cti_channel_setop(struct device *dev, enum cti_chan_set_op op,
 	return err;
 }
 
+static void cti_add_sysfs_link(struct cti_drvdata *drvdata,
+			       struct cti_trig_con *tc)
+{
+	struct coresight_sysfs_link link_info;
+
+	link_info.orig = drvdata->csdev;
+	link_info.orig_name = tc->con_dev_name;
+	link_info.target = tc->con_dev;
+	link_info.target_name = dev_name(&drvdata->csdev->dev);
+	coresight_add_sysfs_link(&link_info);

+}
+
+static void cti_remove_all_sysfs_links(struct cti_drvdata *drvdata)
+{
+	struct cti_trig_con *tc;
+	struct cti_device *ctidev = &drvdata->ctidev;
+	struct coresight_sysfs_link link_info;
+
+	/* origin device and target link name constant for this cti */
+	link_info.orig = drvdata->csdev;
+	link_info.target_name = dev_name(&drvdata->csdev->dev);
+
+	list_for_each_entry(tc, &ctidev->trig_cons, node) {
+		if (tc->con_dev) {
+			link_info.target = tc->con_dev;
+			link_info.orig_name = tc->con_dev_name;
+			coresight_remove_sysfs_link(&link_info);
+		}
+	}
+}
+
 /*
  * Look for a matching connection device name in the list of connections.
  * If found then swap in the csdev name, set trig con association pointer

@@ -452,6 +483,8 @@ cti_match_fixup_csdev(struct cti_device *ctidev, const char *node_name,
 {
 	struct cti_trig_con *tc;
 	const char *csdev_name;
+	struct cti_drvdata *drvdata = container_of(ctidev, struct cti_drvdata,
+						   ctidev);
 
 	list_for_each_entry(tc, &ctidev->trig_cons, node) {
 		if (tc->con_dev_name) {

@@ -462,6 +495,7 @@ cti_match_fixup_csdev(struct cti_device *ctidev, const char *node_name,
 					devm_kstrdup(&csdev->dev, csdev_name,
 						     GFP_KERNEL);
 				tc->con_dev = csdev;
+				cti_add_sysfs_link(drvdata, tc);
 				return true;
 			}
 		}

@@ -546,10 +580,12 @@ static void cti_update_conn_xrefs(struct cti_drvdata *drvdata)
 	struct cti_device *ctidev = &drvdata->ctidev;
 
 	list_for_each_entry(tc, &ctidev->trig_cons, node) {
-		if (tc->con_dev)
+		if (tc->con_dev) {
 			/* set tc->con_dev->ect_dev */
 			coresight_set_assoc_ectdev_mutex(tc->con_dev,
 							 drvdata->csdev);
+			cti_add_sysfs_link(drvdata, tc);
+		}
 	}
 }
 

@@ -602,6 +638,9 @@ static void cti_device_release(struct device *dev)
 	mutex_lock(&ect_mutex);
 	cti_remove_conn_xrefs(drvdata);
 
+	/* clear the dynamic sysfs associate with connections */