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_path().

dti_get_node_by_path() retrieves a node by its path like
get_node_by_path() 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      |  3 ++-
 livetree.c | 15 ++++++++++++++-
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/checks.c b/checks.c
index 9744431..b2b1bf7 100644
--- a/checks.c
+++ b/checks.c

@@ -740,7 +740,7 @@ static void check_alias_paths(struct check *c, struct dt_info *dti,
 
 		/* This check does not work for overlays nor addons with external paths */
 		if (!(dti->dtsflags & (DTSF_PLUGIN | DTSF_ADDON)) &&
-		    (!prop->val.val || !get_node_by_path(dti->dt, prop->val.val))) {
+		    (!prop->val.val || !dti_get_node_by_path(dti, prop->val.val))) {
 			FAIL_PROP(c, dti, node, prop, "aliases property is not a valid node (%s)",
 				  prop->val.val);
 			continue;

diff --git a/dtc.h b/dtc.h
index 4ebe576..8ba093f 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_path(struct node *tree, const char *path);
 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);

@@ -357,6 +356,8 @@ struct dt_info {
 	const char *outname;		/* filename being written to, "-" for stdout */
 };
 
+struct node *dti_get_node_by_path(struct dt_info *dti, const char *path);
+
 /* DTS version flags definitions */
 #define DTSF_V1		0x0001	/* /dts-v1/ */
 #define DTSF_PLUGIN	0x0002	/* /plugin/ */

diff --git a/livetree.c b/livetree.c
index 285f6e1..23ba957 100644
--- a/livetree.c
+++ b/livetree.c

@@ -659,7 +659,7 @@ struct node *get_subnode(struct node *node, const char *nodename)
 	return NULL;
 }
 
-struct node *get_node_by_path(struct node *tree, const char *path)
+static struct node *get_node_by_path(struct node *tree, const char *path)
 {
 	const char *p;
 	struct node *child;

@@ -785,6 +785,19 @@ struct node *get_node_by_ref(struct node *tree, const char *ref)
 	return target;
 }
 
+struct node *dti_get_node_by_path(struct dt_info *dti, const char *path)
+{
+	struct node *node;
+
+	if (dti->dt) {
+		node = get_node_by_path(dti->dt, path);
+		if (node)
+			return node;
+	}
+
+	return NULL;
+}
+
 static void add_phandle_property(struct node *node,
 				 const char *name, int format)
 {

-- 
2.52.0