[PATCH v3 1/4] pylibfdt: Add a method to access the device tree directly

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When calling libfdt functions which are not supported by the Fdt class it
is necessary to get direct access to the device tree data. At present this
requries using the internal _fdt member. Add a new method to provide
public access to this, without allowing the data to be changed.

Note that a bytearray type is returned rather than str, since the swig
types are set up for bytearray to map correctly to const void *.

Signed-off-by: Simon Glass <sjg@xxxxxxxxxxxx>
---

Changes in v3:
- Copy the bytearray before returning it, so the data cannot be changed

Changes in v2:
- Change from get_fdt() to as_bytearray()

 pylibfdt/libfdt.i       | 11 +++++++++++
 tests/pylibfdt_tests.py |  5 +++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/pylibfdt/libfdt.i b/pylibfdt/libfdt.i
index 415820d..29695bb 100644
--- a/pylibfdt/libfdt.i
+++ b/pylibfdt/libfdt.i
@@ -174,6 +174,17 @@ class Fdt:
         self._fdt = bytearray(data)
         check_err(fdt_check_header(self._fdt));
 
+    def as_bytearray(self):
+        """Get the device tree contents as a bytearray
+
+        This can be passed directly to libfdt functions that access a
+        const void * for the device tree.
+
+        Returns:
+            bytearray containing the device tree
+        """
+        return bytearray(self._fdt)
+
     def subnode_offset(self, parentoffset, name, quiet=()):
         """Get the offset of a named subnode
 
diff --git a/tests/pylibfdt_tests.py b/tests/pylibfdt_tests.py
index 95d911a..0ec0f38 100644
--- a/tests/pylibfdt_tests.py
+++ b/tests/pylibfdt_tests.py
@@ -297,9 +297,10 @@ class PyLibfdtTests(unittest.TestCase):
 
     def testIntegers(self):
         """Check that integers can be passed and returned"""
-        self.assertEquals(0, libfdt.fdt_get_phandle(self.fdt._fdt, 0))
+        self.assertEquals(0, libfdt.fdt_get_phandle(self.fdt.as_bytearray(), 0))
         node2 = self.fdt.path_offset('/subnode@2')
-        self.assertEquals(0x2000, libfdt.fdt_get_phandle(self.fdt._fdt, node2))
+        self.assertEquals(
+                0x2000, libfdt.fdt_get_phandle(self.fdt.as_bytearray(), node2))
 
     def testGetPhandle(self):
         """Test for the get_phandle() method"""
-- 
2.17.0.441.gb46fe60e1d-goog

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