/**
* add_changeset_node() - add @node (and children) to overlay changeset
* @ovcs: overlay changeset
* @target_node: where to place @node in live tree
* @node: node from within overlay device tree fragment
*
* If @node does not already exist in @target_node, add changeset entry
* to add @node in @target_node.
*
* If @node already exists in @target_node, and the existing node has
* a phandle, the overlay node is not allowed to have a phandle.
*
* If @node has child nodes, add the children recursively via
* build_changeset_next_level().
*
* NOTE_1: A live devicetree created from a flattened device tree (FDT) will
* not contain the full path in node->full_name. Thus an overlay
* created from an FDT also will not contain the full path in
* node->full_name. However, a live devicetree created from Open
* Firmware may have the full path in node->full_name.
*
* add_changeset_node() follows the FDT convention and does not include
* the full path in node->full_name. Even though it expects the overlay
* to not contain the full path, it uses kbasename() to remove the
* full path should it exist. It also uses kbasename() in comparisons
* to nodes in the live devicetree so that it can apply an overlay to
* a live devicetree created from Open Firmware.
*
* NOTE_2: Multiple mods of created nodes not supported.
* If more than one fragment contains a node that does not already exist
* in the live tree, then for each fragment of_changeset_attach_node()
* will add a changeset entry to add the node. When the changeset is
* applied, __of_attach_node() will attach the node twice (once for
* each fragment). At this point the device tree will be corrupted.
*
* TODO: add integrity check to ensure that multiple fragments do not
* create the same node.
*
* Returns 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if
* invalid @overlay.
*/
static int add_changeset_node(struct overlay_changeset *ovcs,
struct device_node *target_node, struct device_node *node)
{
const char *node_kbasename;
struct device_node *tchild;
int ret = 0;
node_kbasename = kbasename(node->full_name);
for_each_child_of_node(target_node, tchild)
if (!of_node_cmp(node_kbasename, kbasename(tchild->full_name)))
break;
if (!tchild) {
tchild = __of_node_dup(node, node_kbasename);
if (!tchild)
return -ENOMEM;
tchild->parent = target_node;
ret = of_changeset_attach_node(&ovcs->cset, tchild);
if (ret)
return ret;
return build_changeset_next_level(ovcs, tchild, node);
}
if (node->phandle && tchild->phandle)
ret = -EINVAL;
else
ret = build_changeset_next_level(ovcs, tchild, node);
of_node_put(tchild);
return ret;
}
static int of_overlay_apply_single_device_node(struct of_overlay *ov,
struct device_node *target, struct device_node *child)
{
const char *cname;
struct device_node *tchild;
int ret = 0;
cname = kbasename(child->full_name);
if (cname == NULL)
return -ENOMEM;
/* NOTE: Multiple mods of created nodes not supported */
tchild = of_get_child_by_name(target, cname);
if (tchild != NULL) {
/* apply overlay recursively */
ret = of_overlay_apply_one(ov, tchild, child);
of_node_put(tchild);
} else {
/* create empty tree as a target */
tchild = __of_node_dup(child, "%s/%s", target->full_name, cname);
if (!tchild)
return -ENOMEM;
/* point to parent */
tchild->parent = target;
ret = of_changeset_attach_node(&ov->cset, tchild);
if (ret)
return ret;
ret = of_overlay_apply_one(ov, tchild, child);
if (ret)
return ret;
}
return ret;
}
