binman: Centralise device-tree updates within binman

At present we have a few calls to device-tree functions in binman and plan
to add more as we add new entry types which need to report their results.

It makes sense to put this code in a central place so that we can make
sure all device trees are updated. At present we only have U-Boot proper,
but plan to add SPL and TPL too.

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

tools/binman/state.py

@@ -118,3 +118,38 @@ def GetFdts():
     """
     yield main_dtb
 
+def GetUpdateNodes(node):
+    """Yield all the nodes that need to be updated in all device trees
+
+    The property referenced by this node is added to any device trees which
+    have the given node. Due to removable of unwanted notes, SPL and TPL may
+    not have this node.
+
+    Args:
+        node: Node object in the main device tree to look up
+
+    Yields:
+        Node objects in each device tree that is in use (U-Boot proper, which
+            is node, SPL and TPL)
+    """
+    yield node
+
+def AddZeroProp(node, prop):
+    """Add a new property to affected device trees with an integer value of 0.
+
+    Args:
+        prop_name: Name of property
+    """
+    for n in GetUpdateNodes(node):
+        n.AddZeroProp(prop)
+
+def SetInt(node, prop, value):
+    """Update an integer property in affected device trees with an integer value
+
+    This is not allowed to change the size of the FDT.
+
+    Args:
+        prop_name: Name of property
+    """
+    for n in GetUpdateNodes(node):
+        n.SetInt(prop, value)