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+.. _OPAL_GET_DEVICE_TREE:
+
+OPAL_GET_DEVICE_TREE
+====================
+
+.. code-block:: c
+
+   #define OPAL_GET_DEVICE_TREE			118
+
+   int64_t opal_get_device_tree(uint32_t phandle, uint64_t buf, uint64_t len);
+
+Get device sub-tree.
+
+``uint32_t phandle``
+  root device node phandle of the device sub-tree
+``uint64_t buf``
+  FDT blob buffer or NULL
+``uint64_t len``
+  length of the FDT blob buffer
+
+
+Retrieve device sub-tree. The root node's phandle is identified by @phandle.
+The typical use is for the kernel to update its device tree following a change
+in hardware (e.g. PCI hotplug).
+
+Return Codes
+^^^^^^^^^^^^
+
+FDT blob size
+  returned FDT blob buffer size when ``buf`` is NULL
+
+:ref:`OPAL_SUCCESS`
+  FDT blob is created successfully
+:ref:`OPAL_PARAMETER`
+  invalid argument @phandle or @len
+:ref:`OPAL_INTERNAL_ERROR`
+  failure creating FDT blob when calculating its size
+:ref:`OPAL_NO_MEM`
+  not enough room in buffer for device sub-tree
+:ref:`OPAL_EMPTY`
+  failure creating FDT blob