The future introduction of orphan nodes for addons device-tree will lead
to more than one tree in the addons data. Those trees will be:
  - the classical root tree starting at the root node
  - trees related to orphan nodes

Also, an addon device-tree can have only trees based on orphan nodes. In
other words an addon device-tree is valid without having the classical
'root' tree.

To prepare this change, introduce and use dti_get_node_by_label().

dti_get_node_by_label() retrieves a node by its label like
get_node_by_label() but it works at the struct dt_info level.

It handles the case where a 'root' device-tree is not present and will
handle orphan nodes trees as soon as they will be introduced.

This introduction doesn't lead to any functional changes.

Signed-off-by: Herve Codina <herve.codina@bootlin.com>
---
 checks.c   |  2 +-
 dtc.h      |  2 +-
 livetree.c | 15 ++++++++++++++-
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/checks.c b/checks.c
index b2b1bf7..a76e96a 100644
--- a/checks.c
+++ b/checks.c
@@ -444,7 +444,7 @@ static void check_duplicate_label(struct check *c, struct dt_info *dti,
 	struct property *otherprop = NULL;
 	struct marker *othermark = NULL;
 
-	othernode = get_node_by_label(dt, label);
+	othernode = dti_get_node_by_label(dti, label);
 
 	if (!othernode)
 		otherprop = get_property_by_label(dt, label, &othernode);
diff --git a/dtc.h b/dtc.h
index 8ba093f..3dce237 100644
--- a/dtc.h
+++ b/dtc.h
@@ -323,7 +323,6 @@ struct property *get_property_by_label(struct node *tree, const char *label,
 struct marker *get_marker_label(struct node *tree, const char *label,
 				struct node **node, struct property **prop);
 struct node *get_subnode(struct node *node, const char *nodename);
-struct node *get_node_by_label(struct node *tree, const char *label);
 struct node *get_node_by_phandle(struct node *tree, cell_t phandle);
 struct node *get_node_by_ref(struct node *tree, const char *ref);
 cell_t get_node_phandle(struct node *root, struct node *node);
@@ -357,6 +356,7 @@ struct dt_info {
 };
 
 struct node *dti_get_node_by_path(struct dt_info *dti, const char *path);
+struct node *dti_get_node_by_label(struct dt_info *dti, const char *label);
 
 /* DTS version flags definitions */
 #define DTSF_V1		0x0001	/* /dts-v1/ */
diff --git a/livetree.c b/livetree.c
index 23ba957..771ff3d 100644
--- a/livetree.c
+++ b/livetree.c
@@ -685,7 +685,7 @@ static struct node *get_node_by_path(struct node *tree, const char *path)
 	return NULL;
 }
 
-struct node *get_node_by_label(struct node *tree, const char *label)
+static struct node *get_node_by_label(struct node *tree, const char *label)
 {
 	struct node *child, *node;
 	struct label *l;
@@ -798,6 +798,19 @@ struct node *dti_get_node_by_path(struct dt_info *dti, const char *path)
 	return NULL;
 }
 
+struct node *dti_get_node_by_label(struct dt_info *dti, const char *label)
+{
+	struct node *node;
+
+	if (dti->dt) {
+		node = get_node_by_label(dti->dt, label);
+		if (node)
+			return node;
+	}
+
+	return NULL;
+}
+
 static void add_phandle_property(struct node *node,
 				 const char *name, int format)
 {
-- 
2.52.0