of: improve reporting invalid overlay target path

Errors while developing the patch to create of_overlay_fdt_apply()
exposed inadequate error messages to debug problems when overlay
devicetree fragment nodes contain an invalid target path.  Improve
the messages in find_target_node() to remedy this.

Signed-off-by: Frank Rowand <frank.rowand@sony.com>

diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
index e3d7f69..b930e05 100644 (file)
--- a/drivers/of/overlay.c
+++ b/drivers/of/overlay.c
@@ -488,20 +488,30 @@ static int build_changeset(struct overlay_changeset *ovcs)
  */
 static struct device_node *find_target_node(struct device_node *info_node)
 {
+       struct device_node *node;
        const char *path;
        u32 val;
        int ret;
 
        ret = of_property_read_u32(info_node, "target", &val);
-       if (!ret)
-               return of_find_node_by_phandle(val);
+       if (!ret) {
+               node = of_find_node_by_phandle(val);
+               if (!node)
+                       pr_err("find target, node: %pOF, phandle 0x%x not found\n",
+                              info_node, val);
+               return node;
+       }
 
        ret = of_property_read_string(info_node, "target-path", &path);
-       if (!ret)
-               return of_find_node_by_path(path);
+       if (!ret) {
+               node =  of_find_node_by_path(path);
+               if (!node)
+                       pr_err("find target, node: %pOF, path '%s' not found\n",
+                              info_node, path);
+               return node;
+       }
 
-       pr_err("Failed to find target for node %p (%s)\n",
-               info_node, info_node->name);
+       pr_err("find target, node: %pOF, no target property\n", info_node);
 
        return NULL;
 }