binman: Support finding symbols in sub-sections

At present binman only supports resolving symbols in the same section as
the binary that uses it. This is quite limited because we often need to
group entries into different sections.

Enhance the algorithm to search the entire image for symbols.

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

tools/binman/image.py

@@ -324,3 +324,48 @@ class Image(section.Entry_section):
             _DoLine(lines, _EntryToStrings(entry))
             selected_entries.append(entry)
         return selected_entries, lines, widths
+
+    def LookupImageSymbol(self, sym_name, optional, msg, base_addr):
+        """Look up a symbol in an ELF file
+
+        Looks up a symbol in an ELF file. Only entry types which come from an
+        ELF image can be used by this function.
+
+        This searches through this image including all of its subsections.
+
+        At present the only entry properties supported are:
+            offset
+            image_pos - 'base_addr' is added if this is not an end-at-4gb image
+            size
+
+        Args:
+            sym_name: Symbol name in the ELF file to look up in the format
+                _binman_<entry>_prop_<property> where <entry> is the name of
+                the entry and <property> is the property to find (e.g.
+                _binman_u_boot_prop_offset). As a special case, you can append
+                _any to <entry> to have it search for any matching entry. E.g.
+                _binman_u_boot_any_prop_offset will match entries called u-boot,
+                u-boot-img and u-boot-nodtb)
+            optional: True if the symbol is optional. If False this function
+                will raise if the symbol is not found
+            msg: Message to display if an error occurs
+            base_addr: Base address of image. This is added to the returned
+                image_pos in most cases so that the returned position indicates
+                where the targeted entry/binary has actually been loaded. But
+                if end-at-4gb is used, this is not done, since the binary is
+                already assumed to be linked to the ROM position and using
+                execute-in-place (XIP).
+
+        Returns:
+            Value that should be assigned to that symbol, or None if it was
+                optional and not found
+
+        Raises:
+            ValueError if the symbol is invalid or not found, or references a
+                property which is not supported
+        """
+        entries = OrderedDict()
+        entries_by_name = {}
+        self._CollectEntries(entries, entries_by_name, self)
+        return self.LookupSymbol(sym_name, optional, msg, base_addr,
+                                 entries_by_name)