pylibfdt: Support device-tree creation/expansion
Add support for fdt_open_into() and fdt_create_empty_tree() from the
Python library. The former is named resize() since it better fits with
what the Python binding actually does.
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
diff --git a/pylibfdt/libfdt.i b/pylibfdt/libfdt.i
index 2074e9b..da32148 100644
--- a/pylibfdt/libfdt.i
+++ b/pylibfdt/libfdt.i
@@ -434,6 +434,39 @@
return pdata
return Property(pdata[0], pdata[1])
+ @staticmethod
+ def create_empty_tree(size, quiet=()):
+ """Create an empty device tree ready for use
+
+ Args:
+ size: Size of device tree in bytes
+
+ Returns:
+ Fdt object containing the device tree
+ """
+ data = bytearray(size)
+ err = check_err(fdt_create_empty_tree(data, size), quiet)
+ if err:
+ return err
+ return Fdt(data)
+
+ def resize(self, size, quiet=()):
+ """Move the device tree into a larger or smaller space
+
+ This creates a new device tree of size @size and moves the existing
+ device tree contents over to that. It can be used to create more space
+ in a device tree. Note that the Fdt object remains the same, but it
+ now has a new bytearray holding the contents.
+
+ Args:
+ size: Required new size of device tree in bytes
+ """
+ fdt = bytearray(size)
+ err = check_err(fdt_open_into(self._fdt, fdt, size), quiet)
+ if err:
+ return err
+ self._fdt = fdt
+
def pack(self, quiet=()):
"""Pack the device tree to remove unused space
diff --git a/tests/pylibfdt_tests.py b/tests/pylibfdt_tests.py
index b624f7b..ea38b78 100644
--- a/tests/pylibfdt_tests.py
+++ b/tests/pylibfdt_tests.py
@@ -55,7 +55,7 @@
sys.path.insert(0, '../pylibfdt')
import libfdt
-from libfdt import FdtException, QUIET_NOTFOUND, QUIET_ALL
+from libfdt import Fdt, FdtException, QUIET_NOTFOUND, QUIET_ALL
def get_err(err_code):
"""Convert an error code into an error message
@@ -364,6 +364,22 @@
self.fdt.get_mem_rsv(0))
self.assertEquals([123456789, 010000], self.fdt.get_mem_rsv(1))
+ def testEmpty(self):
+ """Test that we can create an empty tree"""
+ self.assertEquals(-libfdt.NOSPACE,
+ Fdt.create_empty_tree(1, (libfdt.NOSPACE,)))
+ fdt = Fdt.create_empty_tree(128)
+ self.assertEquals(128, fdt.totalsize())
+
+ def testOpenInto(self):
+ """Test that we can resize a tree"""
+ fdt = Fdt.create_empty_tree(128)
+ self.assertEquals(128, fdt.totalsize())
+ fdt.resize(256)
+ self.assertEquals(256, fdt.totalsize())
+ fdt.pack()
+ self.assertTrue(fdt.totalsize() < 128)
+
if __name__ == "__main__":
unittest.main()
