binman: Support reading an image into an Image object

It is possible to read an Image, locate its FDT map and then read it into
the binman data structures. This allows full access to the entries that
were written to the image. Add support for this.

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

1 files changed, 38 insertions, 0 deletions

diff --git a/tools/binman/image.py b/tools/binman/image.py
index 6f4bd5d..f890350 100644
--- a/tools/binman/image.py
+++ b/tools/binman/image.py
@@ -12,6 +12,9 @@ from operator import attrgetter
 import re
 import sys
 
+from etype import fdtmap
+from etype import image_header
+import fdt
 import fdt_util
 import bsection
 import tools
@@ -47,6 +50,41 @@ class Image:
         else:
             self._ReadNode()
 
+    @classmethod
+    def FromFile(cls, fname):
+        """Convert an image file into an Image for use in binman
+
+        Args:
+            fname: Filename of image file to read
+
+        Returns:
+            Image object on success
+
+        Raises:
+            ValueError if something goes wrong
+        """
+        data = tools.ReadFile(fname)
+        size = len(data)
+
+        # First look for an image header
+        pos = image_header.LocateHeaderOffset(data)
+        if pos is None:
+            # Look for the FDT map
+            pos = fdtmap.LocateFdtmap(data)
+        if pos is None:
+            raise ValueError('Cannot find FDT map in image')
+
+        # We don't know the FDT size, so check its header first
+        probe_dtb = fdt.Fdt.FromData(
+            data[pos + fdtmap.FDTMAP_HDR_LEN:pos + 256])
+        dtb_size = probe_dtb.GetFdtObj().totalsize()
+        fdtmap_data = data[pos:pos + dtb_size + fdtmap.FDTMAP_HDR_LEN]
+        dtb = fdt.Fdt.FromData(fdtmap_data[fdtmap.FDTMAP_HDR_LEN:])
+        dtb.Scan()
+
+        # Return an Image with the associated nodes
+        return Image('image', dtb.GetRoot())
+
     def _ReadNode(self):
         """Read properties from the image node"""
         self._size = fdt_util.GetInt(self._node, 'size')