binman: Adjust fmap to ignore CBFS files

The FMAP is not intended to show the files inside a CBFS. The FMAP can be
used to locate the CBFS itself, but then the CBFS must be read to find out
what is in it.

Update the FMAP to work this way and add some debugging while we are here.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/binman/README.entries b/tools/binman/README.entries
index 37b8b4c..0f0e367 100644
--- a/tools/binman/README.entries
+++ b/tools/binman/README.entries
@@ -314,7 +314,8 @@
 
 When used, this entry will be populated with an FMAP which reflects the
 entries in the current image. Note that any hierarchy is squashed, since
-FMAP does not support this.
+FMAP does not support this. Also, CBFS entries appear as a single entry -
+the sub-entries are ignored.
 
 
 
diff --git a/tools/binman/etype/fmap.py b/tools/binman/etype/fmap.py
index 56677cb..835ba50 100644
--- a/tools/binman/etype/fmap.py
+++ b/tools/binman/etype/fmap.py
@@ -8,6 +8,8 @@
 from entry import Entry
 import fmap_util
 import tools
+from tools import ToHexSize
+import tout
 
 
 class Entry_fmap(Entry):
@@ -26,7 +28,8 @@
 
     When used, this entry will be populated with an FMAP which reflects the
     entries in the current image. Note that any hierarchy is squashed, since
-    FMAP does not support this.
+    FMAP does not support this. Also, CBFS entries appear as a single entry -
+    the sub-entries are ignored.
     """
     def __init__(self, section, etype, node):
         Entry.__init__(self, section, etype, node)
@@ -39,7 +42,9 @@
         """
         def _AddEntries(areas, entry):
             entries = entry.GetEntries()
-            if entries:
+            tout.Debug("fmap: Add entry '%s' type '%s' (%s subentries)" %
+                       (entry.GetPath(), entry.etype, ToHexSize(entries)))
+            if entries and entry.etype != 'cbfs':
                 for subentry in entries.values():
                     _AddEntries(areas, subentry)
             else: