Function dt_import_fragment

src/commonlib/device_tree.c:2024–2067

* Apply an overlay /fragment@X node to a base device tree. * * @param tree Base device tree. * @param fragment /fragment@X node. * @params overlay_symbols /__symbols__ node of the overlay. * * @return 0 on success, -1 on error. */

 * @return		0 on success, -1 on error.
 */
static int dt_import_fragment(struct device_tree *tree,
			      struct device_tree_node *fragment,
			      struct device_tree_node *overlay_symbols)
{
	/* The actual overlaid nodes/props are in an __overlay__ child node. */
	static const char *overlay_path[] = { "__overlay__", NULL };
	struct device_tree_node *overlay = dt_find_node(fragment, overlay_path,
							NULL, NULL, 0);

	/* If it doesn't have an __overlay__ child, it's not a fragment. */
	if (!overlay)
		return 0;

	/* Target node of the fragment can be given by path or by phandle. */
	struct device_tree_property *prop;
	struct device_tree_property *phandle = NULL;
	struct device_tree_property *path = NULL;
	list_for_each(prop, fragment->properties, list_node) {
		if (!strcmp(prop->prop.name, "target")) {
			phandle = prop;
			break; /* phandle target has priority, stop looking */
		}
		if (!strcmp(prop->prop.name, "target-path"))
			path = prop;
	}

	struct device_tree_node *target = NULL;
	if (phandle) {
		if (phandle->prop.size != sizeof(uint32_t))
			return -1;
		target = dt_find_node_by_phandle(tree->root,
						 be32dec(phandle->prop.data));
		/* Symbols already updated as part of dt_fixup_external(). */
	} else if (path) {
		target = dt_find_node_by_path(tree, path->prop.data,
					      NULL, NULL, 0);
		dt_fix_symbols(overlay_symbols, fragment, path->prop.data);
	}
	if (!target)
		return -1;

	dt_copy_subtree(target, overlay, 1);
	return 0;
}

/*
 * Apply a device tree overlay to a base device tree. This will