dtoc: Create a base class for Fdt

At present we have two separate implementations of the Fdt library, one which
uses fdtget/fdtput and one which uses libfdt (via swig).

Before adding more functionality it makes sense to create a base class for
these. This will allow common functions to be shared, and make the Fdt API
a little clearer.

Create a new fdt.py file with the base class, and adjust fdt_normal.py and
fdt_fallback.py to use it.

Signed-off-by: Simon Glass <sjg@chromium.org>

1 files changed, 37 insertions, 24 deletions

diff --git a/tools/dtoc/fdt_fallback.py b/tools/dtoc/fdt_fallback.py
index 9ed11e4cbf..be3b5badc9 100644
--- a/tools/dtoc/fdt_fallback.py
+++ b/tools/dtoc/fdt_fallback.py
@@ -7,6 +7,8 @@
 #
 
 import command
+import fdt
+from fdt import Fdt, NodeBase, PropBase
 import fdt_util
 import sys
 
@@ -17,7 +19,7 @@ import sys
 # is not very efficient for larger trees. The tool is called once for each
 # node and property in the tree.
 
-class Prop:
+class Prop(PropBase):
     """A device tree property
 
     Properties:
@@ -26,14 +28,14 @@ class Prop:
             bytes
         type: Value type
     """
-    def __init__(self, name, byte_list_str):
-        self.name = name
-        self.value = None
+    def __init__(self, node, name, byte_list_str):
+        PropBase.__init__(self, node, 0, name)
         if not byte_list_str.strip():
             self.type = fdt_util.TYPE_BOOL
             return
-        bytes = [chr(int(byte, 16)) for byte in byte_list_str.strip().split(' ')]
-        self.type, self.value = fdt_util.BytesToValue(''.join(bytes))
+        self.bytes = [chr(int(byte, 16))
+                      for byte in byte_list_str.strip().split(' ')]
+        self.type, self.value = fdt_util.BytesToValue(''.join(self.bytes))
 
     def GetPhandle(self):
         """Get a (single) phandle value from a property
@@ -77,7 +79,7 @@ class Prop:
                 self.value.append(val)
 
 
-class Node:
+class Node(NodeBase):
     """A device tree node
 
     Properties:
@@ -88,12 +90,8 @@ class Node:
         props: A dict of properties for this node, each a Prop object.
             Keyed by property name
     """
-    def __init__(self, fdt, name, path):
-        self.name = name
-        self.path = path
-        self._fdt = fdt
-        self.subnodes = []
-        self.props = {}
+    def __init__(self, fdt, offset, name, path):
+        NodeBase.__init__(self, fdt, offset, name, path)
 
     def Scan(self):
         """Scan a node's properties and subnodes
@@ -102,35 +100,34 @@ class Node:
         searching into subnodes so that the entire tree is built.
         """
         for name, byte_list_str in self._fdt.GetProps(self.path).iteritems():
-            prop = Prop(name, byte_list_str)
+            prop = Prop(self, name, byte_list_str)
             self.props[name] = prop
 
         for name in self._fdt.GetSubNodes(self.path):
             sep = '' if self.path[-1] == '/' else '/'
             path = self.path + sep + name
-            node = Node(self._fdt, name, path)
+            node = Node(self._fdt, 0, name, path)
             self.subnodes.append(node)
 
             node.Scan()
 
 
-class Fdt:
-    """Provides simple access to a flat device tree blob.
+class FdtFallback(Fdt):
+    """Provides simple access to a flat device tree blob using fdtget/fdtput
 
     Properties:
-      fname: Filename of fdt
-      _root: Root of device tree (a Node object)
+        See superclass
     """
 
     def __init__(self, fname):
-        self.fname = fname
+        Fdt.__init__(self, fname)
 
     def Scan(self):
         """Scan a device tree, building up a tree of Node objects
 
         This fills in the self._root property
         """
-        self._root = Node(self, '/', '/')
+        self._root = Node(self, 0, '/', '/')
         self._root.Scan()
 
     def GetRoot(self):
@@ -153,7 +150,7 @@ class Fdt:
         Raises:
             CmdError: if the node does not exist.
         """
-        out = command.Output('fdtget', self.fname, '-l', node)
+        out = command.Output('fdtget', self._fname, '-l', node)
         return out.strip().splitlines()
 
     def GetProps(self, node, convert_dashes=False):
@@ -171,7 +168,7 @@ class Fdt:
         Raises:
             CmdError: if the node does not exist.
         """
-        out = command.Output('fdtget', self.fname, node, '-p')
+        out = command.Output('fdtget', self._fname, node, '-p')
         props = out.strip().splitlines()
         props_dict = {}
         for prop in props:
@@ -204,10 +201,26 @@ class Fdt:
         Raises:
             CmdError: if the property does not exist and no default is provided.
         """
-        args = [self.fname, node, prop, '-t', 'bx']
+        args = [self._fname, node, prop, '-t', 'bx']
         if default is not None:
           args += ['-d', str(default)]
         if typespec is not None:
           args += ['-t%s' % typespec]
         out = command.Output('fdtget', *args)
         return out.strip()
+
+    @classmethod
+    def Node(self, fdt, offset, name, path):
+        """Create a new node
+
+        This is used by Fdt.Scan() to create a new node using the correct
+        class.
+
+        Args:
+            fdt: Fdt object
+            offset: Offset of node
+            name: Node name
+            path: Full path to node
+        """
+        node = Node(fdt, offset, name, path)
+        return node