1 files changed, 71 insertions, 0 deletions

diff --git a/drivers/of/base.c b/drivers/of/base.c
index cf89ee6253f3..2ce58be314af 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -870,3 +870,74 @@ int prom_update_property(struct device_node *np,
 
         return 0;
 }
+
+#if defined(CONFIG_OF_DYNAMIC)
+/*
+ * Support for dynamic device trees.
+ *
+ * On some platforms, the device tree can be manipulated at runtime.
+ * The routines in this section support adding, removing and changing
+ * device tree nodes.
+ */
+
+/**
+ * of_attach_node - Plug a device node into the tree and global list.
+ */
+void of_attach_node(struct device_node *np)
+{
+        unsigned long flags;
+
+        write_lock_irqsave(&devtree_lock, flags);
+        np->sibling = np->parent->child;
+        np->allnext = allnodes;
+        np->parent->child = np;
+        allnodes = np;
+        write_unlock_irqrestore(&devtree_lock, flags);
+}
+
+/**
+ * of_detach_node - "Unplug" a node from the device tree.
+ *
+ * The caller must hold a reference to the node.  The memory associated with
+ * the node is not freed until its refcount goes to zero.
+ */
+void of_detach_node(struct device_node *np)
+{
+        struct device_node *parent;
+        unsigned long flags;
+
+        write_lock_irqsave(&devtree_lock, flags);
+
+        parent = np->parent;
+        if (!parent)
+                goto out_unlock;
+
+        if (allnodes == np)
+                allnodes = np->allnext;
+        else {
+                struct device_node *prev;
+                for (prev = allnodes;
+                     prev->allnext != np;
+                     prev = prev->allnext)
+                        ;
+                prev->allnext = np->allnext;
+        }
+
+        if (parent->child == np)
+                parent->child = np->sibling;
+        else {
+                struct device_node *prevsib;
+                for (prevsib = np->parent->child;
+                     prevsib->sibling != np;
+                     prevsib = prevsib->sibling)
+                        ;
+                prevsib->sibling = np->sibling;
+        }
+
+        of_node_set_flag(np, OF_DETACHED);
+
+out_unlock:
+        write_unlock_irqrestore(&devtree_lock, flags);
+}
+#endif /* defined(CONFIG_OF_DYNAMIC) */
+