binman: Allow disabling symbol writing

Some boards don't use symbol writing but do access the symbols in SPL.
Provide an option to work around this.

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

tools/binman/binman.rst

@@ -831,6 +831,13 @@ write-symbols:
     binman. This is automatic for certain entry types, e.g. `u-boot-spl`. See
     binman_syms_ for more information.
 
+no-write-symbols:
+    Disables symbol writing for this entry. This can be used in entry types
+    where symbol writing is automatic. For example, if `u-boot-spl` refers to
+    the `u_boot_any_image_pos` symbol but U-Boot is not available in the image
+    containing SPL, this can be used to disable the writing. Quite likely this
+    indicates a bug in your setup.
+
 elf-filename:
     Sets the file name of a blob's associated ELF file. For example, if the
     blob is `zephyr.bin` then the ELF file may be `zephyr.elf`. This allows

tools/binman/entry.py

@@ -158,6 +158,7 @@ class Entry(object):
         self.offset_from_elf = None
         self.preserve = False
         self.build_done = False
+        self.no_write_symbols = False
 
     @staticmethod
     def FindEntryClass(etype, expanded):
@@ -321,6 +322,7 @@ class Entry(object):
                                                              'offset-from-elf')
 
         self.preserve = fdt_util.GetBool(self._node, 'preserve')
+        self.no_write_symbols = fdt_util.GetBool(self._node, 'no-write-symbols')
 
     def GetDefaultFilename(self):
         return None
@@ -695,7 +697,7 @@ class Entry(object):
         Args:
           section: Section containing the entry
         """
-        if self.auto_write_symbols:
+        if self.auto_write_symbols and not self.no_write_symbols:
             # Check if we are writing symbols into an ELF file
             is_elf = self.GetDefaultFilename() == self.elf_fname
             elf.LookupAndWriteSymbols(self.elf_fname, self, section.GetImage(),

tools/binman/etype/blob_phase.py

@@ -52,3 +52,8 @@ class Entry_blob_phase(Entry_section):
 
         # Read entries again, now that we have some
         self.ReadEntries()
+
+        # Propagate the no-write-symbols property
+        if self.no_write_symbols:
+            for entry in self._entries.values():
+                entry.no_write_symbols = True

tools/binman/ftest.py

@@ -1452,7 +1452,7 @@ class TestFunctional(unittest.TestCase):
         self.assertEqual(U_BOOT_SPL_NODTB_DATA, data[:len(U_BOOT_SPL_NODTB_DATA)])
 
     def checkSymbols(self, dts, base_data, u_boot_offset, entry_args=None,
-                     use_expanded=False):
+                     use_expanded=False, no_write_symbols=False):
         """Check the image contains the expected symbol values
 
         Args:
@@ -1481,6 +1481,11 @@ class TestFunctional(unittest.TestCase):
         sym_values = struct.pack('<LLQLL', elf.BINMAN_SYM_MAGIC_VALUE,
                                  0x00, u_boot_offset + len(U_BOOT_DATA),
                                  0x10 + u_boot_offset, 0x04)
+        if no_write_symbols:
+            expected = (base_data +
+                        tools.get_bytes(0xff, 0x38 - len(base_data)) +
+                        U_BOOT_DATA + base_data)
+        else:
             expected = (sym_values + base_data[24:] +
                         tools.get_bytes(0xff, 1) + U_BOOT_DATA + sym_values +
                         base_data[24:])
@@ -6676,6 +6681,21 @@ fdt         fdtmap                Extract the devicetree blob from the fdtmap
                                 ['fit'])
         self.assertIn("Node '/fit': Missing tool: 'mkimage'", str(e.exception))
 
+    def testSymbolNoWrite(self):
+        """Test disabling of symbol writing"""
+        self.checkSymbols('282_symbols_disable.dts', U_BOOT_SPL_DATA, 0x1c,
+                          no_write_symbols=True)
+
+    def testSymbolNoWriteExpanded(self):
+        """Test disabling of symbol writing in expanded entries"""
+        entry_args = {
+            'spl-dtb': '1',
+        }
+        self.checkSymbols('282_symbols_disable.dts', U_BOOT_SPL_NODTB_DATA +
+                          U_BOOT_SPL_DTB_DATA, 0x38,
+                          entry_args=entry_args, use_expanded=True,
+                          no_write_symbols=True)
+
 
 if __name__ == "__main__":
     unittest.main()

tools/binman/test/282_symbols_disable.dts

@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/dts-v1/;
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	binman {
+		pad-byte = <0xff>;
+		u-boot-spl {
+			no-write-symbols;
+		};
+
+		u-boot {
+			offset = <0x38>;
+			no-expanded;
+		};
+
+		u-boot-spl2 {
+			type = "u-boot-spl";
+			no-write-symbols;
+		};
+	};
+};