binman: Rename 'position' to 'offset'

After some thought, I believe there is an unfortunate naming flaw in
binman. Entries have a position and size, but now that we support
hierarchical sections it is unclear whether a position should be an
absolute position within the image, or a relative position within its
parent section.

At present 'position' actually means the relative position. This indicates
a need for an 'image position' for code that wants to find the location of
an entry without having to do calculations back through parents to
discover this image position.

A better name for the current 'position' or 'pos' is 'offset'. It is not
always an absolute position, but it is always an offset from its parent
offset.

It is unfortunate to rename this concept now, 18 months after binman was
introduced. However I believe it is the right thing to do. The impact is
mostly limited to binman itself and a few changes to in-tree users to
binman:

   tegra
   sunxi
   x86

The change makes old binman definitions (e.g. downstream or out-of-tree)
incompatible if they use the 'pos = <...>' property. Later work will
adjust binman to generate an error when it is used.

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

tools/binman/image.py

@@ -57,7 +57,7 @@ class Image:
     def AddMissingProperties(self):
         """Add properties that are not present in the device tree
 
-        When binman has completed packing the entries the position and size of
+        When binman has completed packing the entries the offset and size of
         each entry are known. But before this the device tree may not specify
         these. Add any missing properties, with a dummy value, so that the
         size of the entry is correct. That way we can insert the correct values
@@ -73,13 +73,13 @@ class Image:
         """
         self._section.GetEntryContents()
 
-    def GetEntryPositions(self):
-        """Handle entries that want to set the position/size of other entries
+    def GetEntryOffsets(self):
+        """Handle entries that want to set the offset/size of other entries
 
-        This calls each entry's GetPositions() method. If it returns a list
+        This calls each entry's GetOffsets() method. If it returns a list
         of entries to update, it updates them.
         """
-        self._section.GetEntryPositions()
+        self._section.GetEntryOffsets()
 
     def PackEntries(self):
         """Pack all entries into the image"""
@@ -121,5 +121,5 @@ class Image:
         filename = '%s.map' % self._name
         fname = tools.GetOutputFilename(filename)
         with open(fname, 'w') as fd:
-            print('%8s  %8s  %s' % ('Position', 'Size', 'Name'), file=fd)
+            print('%8s  %8s  %s' % ('Offset', 'Size', 'Name'), file=fd)
             self._section.WriteMap(fd, 0)