4 files changed, 49 insertions, 17 deletions

diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c
index 4394095ad224..49112a58478e 100644
--- a/drivers/hwtracing/coresight/coresight-platform.c
+++ b/drivers/hwtracing/coresight/coresight-platform.c
@@ -36,7 +36,7 @@ static int coresight_alloc_conns(struct device *dev,
 	return 0;
 }
 
-static int coresight_device_fwnode_match(struct device *dev, void *fwnode)
+int coresight_device_fwnode_match(struct device *dev, void *fwnode)
 {
 	return dev_fwnode(dev) == fwnode;
 }
@@ -219,9 +219,15 @@ static int of_coresight_parse_endpoint(struct device *dev,
 		}
 
 		conn->outport = endpoint.port;
-		conn->child_name = devm_kstrdup(dev,
-						dev_name(rdev),
-						GFP_KERNEL);
+		/*
+		 * Hold the refcount to the target device. This could be
+		 * released via:
+		 * 1) coresight_release_platform_data() if the probe fails or
+		 *    this device is unregistered.
+		 * 2) While removing the target device via
+		 *    coresight_remove_match()
+		 */
+		conn->child_fwnode = fwnode_handle_get(rdev_fwnode);
 		conn->child_port = rendpoint.port;
 		/* Connection record updated */
 		ret = 1;
diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
index c21642114fc3..8b07fe55395a 100644
--- a/drivers/hwtracing/coresight/coresight-priv.h
+++ b/drivers/hwtracing/coresight/coresight-priv.h
@@ -200,8 +200,8 @@ static inline void *coresight_get_uci_data(const struct amba_id *id)
 	return 0;
 }
 
-static inline void
-coresight_release_platform_data(struct coresight_platform_data *pdata)
-{}
+void coresight_release_platform_data(struct coresight_platform_data *pdata);
+
+int coresight_device_fwnode_match(struct device *dev, void *fwnode);
 
 #endif
diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index 526141c2f876..1287778c3be5 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -978,6 +978,7 @@ static void coresight_device_release(struct device *dev)
 {
 	struct coresight_device *csdev = to_coresight_device(dev);
 
+	fwnode_handle_put(csdev->dev.fwnode);
 	kfree(csdev->refcnt);
 	kfree(csdev);
 }
@@ -1009,13 +1010,11 @@ static int coresight_orphan_match(struct device *dev, void *data)
 		/* We have found at least one orphan connection */
 		if (conn->child_dev == NULL) {
 			/* Does it match this newly added device? */
-			if (conn->child_name &&
-			    !strcmp(dev_name(&csdev->dev), conn->child_name)) {
+			if (conn->child_fwnode == csdev->dev.fwnode)
 				conn->child_dev = csdev;
-			} else {
+			else
 				/* This component still has an orphan */
 				still_orphan = true;
-			}
 		}
 	}
 
@@ -1047,9 +1046,9 @@ static void coresight_fixup_device_conns(struct coresight_device *csdev)
 		struct coresight_connection *conn = &csdev->pdata->conns[i];
 		struct device *dev = NULL;
 
-		if (conn->child_name)
-			dev = bus_find_device_by_name(&coresight_bustype, NULL,
-						      conn->child_name);
+		dev = bus_find_device(&coresight_bustype, NULL,
+				      (void *)conn->child_fwnode,
+				      coresight_device_fwnode_match);
 		if (dev) {
 			conn->child_dev = to_coresight_device(dev);
 			/* and put reference from 'bus_find_device()' */
@@ -1084,9 +1083,15 @@ static int coresight_remove_match(struct device *dev, void *data)
 		if (conn->child_dev == NULL)
 			continue;
 
-		if (!strcmp(dev_name(&csdev->dev), conn->child_name)) {
+		if (csdev->dev.fwnode == conn->child_fwnode) {
 			iterator->orphan = true;
 			conn->child_dev = NULL;
+			/*
+			 * Drop the reference to the handle for the remote
+			 * device acquired in parsing the connections from
+			 * platform data.
+			 */
+			fwnode_handle_put(conn->child_fwnode);
 			/* No need to continue */
 			break;
 		}
@@ -1166,6 +1171,22 @@ static int __init coresight_init(void)
 }
 postcore_initcall(coresight_init);
 
+/*
+ * coresight_release_platform_data: Release references to the devices connected
+ * to the output port of this device.
+ */
+void coresight_release_platform_data(struct coresight_platform_data *pdata)
+{
+	int i;
+
+	for (i = 0; i < pdata->nr_outport; i++) {
+		if (pdata->conns[i].child_fwnode) {
+			fwnode_handle_put(pdata->conns[i].child_fwnode);
+			pdata->conns[i].child_fwnode = NULL;
+		}
+	}
+}
+
 struct coresight_device *coresight_register(struct coresight_desc *desc)
 {
 	int ret;
@@ -1210,6 +1231,11 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
 	csdev->dev.parent = desc->dev;
 	csdev->dev.release = coresight_device_release;
 	csdev->dev.bus = &coresight_bustype;
+	/*
+	 * Hold the reference to our parent device. This will be
+	 * dropped only in coresight_device_release().
+	 */
+	csdev->dev.fwnode = fwnode_handle_get(dev_fwnode(desc->dev));
 	dev_set_name(&csdev->dev, "%s", desc->name);
 
 	ret = device_register(&csdev->dev);
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index b67d5074ece0..b40544bc06fe 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -126,15 +126,15 @@ struct coresight_desc {
 /**
  * struct coresight_connection - representation of a single connection
  * @outport:	a connection's output port number.
- * @chid_name:	remote component's name.
  * @child_port:	remote component's port number @output is connected to.
+ * @chid_fwnode: remote component's fwnode handle.
  * @child_dev:	a @coresight_device representation of the component
 		connected to @outport.
  */
 struct coresight_connection {
 	int outport;
-	const char *child_name;
 	int child_port;
+	struct fwnode_handle *child_fwnode;
 	struct coresight_device *child_dev;
 };