dtc: introduce label relative path references

Since introduction of OF_UPSTREAM flag, U-Boot's dtc must be able
to compile Kernel's device tree.

Since kernel commit 7de129f5389b ("ARM: dts: stm32: stm32mp151a-prtt1l:
Fix QSPI configuration"), label relative path references has been
introduced. These label relative path references is not supported
by current U-Boot dtc version 1.5.0: (see mailing list discussion [1]).

In order to support such label relative patch references
adds following commit from upstream DTC tree:

commit 651410e54cb9 ("util: introduce xstrndup helper")
commit ec7986e682cf ("dtc: introduce label relative path references")

[1] https://lore.kernel.org/all/20250115144428.GZ3476@bill-the-cat/T/

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Cc: Tom Rini <trini@konsulko.com>
Cc: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

1 files changed, 30 insertions, 3 deletions

diff --git a/scripts/dtc/livetree.c b/scripts/dtc/livetree.c
index ba06ef348be..4cfc2adccdd 100644
--- a/scripts/dtc/livetree.c
+++ b/scripts/dtc/livetree.c
@@ -583,12 +583,39 @@ struct node *get_node_by_phandle(struct node *tree, cell_t phandle)
 
 struct node *get_node_by_ref(struct node *tree, const char *ref)
 {
+	struct node *target = tree;
+	const char *label = NULL, *path = NULL;
+
 	if (streq(ref, "/"))
 		return tree;
-	else if (ref[0] == '/')
-		return get_node_by_path(tree, ref);
+
+	if (ref[0] == '/')
+		path = ref;
 	else
-		return get_node_by_label(tree, ref);
+		label = ref;
+
+	if (label) {
+		const char *slash = strchr(label, '/');
+		char *buf = NULL;
+
+		if (slash) {
+			buf = xstrndup(label, slash - label);
+			label = buf;
+			path = slash + 1;
+		}
+
+		target = get_node_by_label(tree, label);
+
+		free(buf);
+
+		if (!target)
+			return NULL;
+	}
+
+	if (path)
+		target = get_node_by_path(target, path);
+
+	return target;
 }
 
 cell_t get_node_phandle(struct node *root, struct node *node)