coresight: Use fwnode handle instead of device names

We rely on the device names to find a CoreSight device on the
coresight bus. The device name however is obtained from the platform,
which is bound to the real platform/amba device. As we are about
to use different naming scheme for the coresight devices, we can't
rely on the platform device name to find the corresponding
coresight device. Instead we use the platform agnostic
"fwnode handle" of the parent device to find the devices.
We also reuse the same fwnode as the parent for the Coresight
device we create.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 34 insertions, 8 deletions

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);