binman: Support default alignment for sections

Sometimes it is useful to specify the default alignment for all entries
in a section, such as when word-alignment is necessary, for example. It
is tedious and error-prone to specify this individually for each section.

Add a property to control this for a section.

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

tools/binman/binman.rst

@@ -562,6 +562,13 @@ skip-at-start:
     'end-at-4gb' property is not applicable where CONFIG_SYS_TEXT_BASE +
     Image size != 4gb.
 
+align-default:
+    Specifies the default alignment for entries in this section, if they do
+    not specify an alignment. Note that this only applies to top-level entries
+    in the section (direct subentries), not any subentries of those entries.
+    This means that each section must specify its own default alignment, if
+    required.
+
 Examples of the above options can be found in the tests. See the
 tools/binman/test directory.
 

tools/binman/entries.rst

@@ -796,6 +796,8 @@ Properties / Entry arguments: (see binman README for more information):
         file, since the first 16 bytes are skipped when writing.
     name-prefix: Adds a prefix to the name of every entry in the section
         when writing out the map
+    align_default: Default alignment for this section, if no alignment is
+        given in the entry
 
 Properties:
     allow_missing: True if this section permits external blobs to be

tools/binman/entry.py

@@ -201,6 +201,8 @@ class Entry(object):
         if tools.NotPowerOfTwo(self.align):
             raise ValueError("Node '%s': Alignment %s must be a power of two" %
                              (self._node.path, self.align))
+        if self.section and self.align is None:
+            self.align = self.section.align_default
         self.pad_before = fdt_util.GetInt(self._node, 'pad-before', 0)
         self.pad_after = fdt_util.GetInt(self._node, 'pad-after', 0)
         self.align_size = fdt_util.GetInt(self._node, 'align-size')

tools/binman/etype/cbfs.py

@@ -169,6 +169,7 @@ class Entry_cbfs(Entry):
 
         super().__init__(section, etype, node)
         self._cbfs_arg = fdt_util.GetString(node, 'cbfs-arch', 'x86')
+        self.align_default = None
         self._cbfs_entries = OrderedDict()
         self._ReadSubnodes()
         self.reader = None

tools/binman/etype/mkimage.py

@@ -36,6 +36,7 @@ class Entry_mkimage(Entry):
         super().__init__(section, etype, node)
         self._args = fdt_util.GetString(self._node, 'args').split(' ')
         self._mkimage_entries = OrderedDict()
+        self.align_default = None
         self._ReadSubnodes()
 
     def ObtainContents(self):

tools/binman/etype/section.py

@@ -36,6 +36,8 @@ class Entry_section(Entry):
             file, since the first 16 bytes are skipped when writing.
         name-prefix: Adds a prefix to the name of every entry in the section
             when writing out the map
+        align_default: Default alignment for this section, if no alignment is
+            given in the entry
 
     Properties:
         allow_missing: True if this section permits external blobs to be
@@ -76,6 +78,7 @@ class Entry_section(Entry):
             if self._skip_at_start is None:
                 self._skip_at_start = 0
         self._name_prefix = fdt_util.GetString(self._node, 'name-prefix')
+        self.align_default = fdt_util.GetInt(self._node, 'align-default', 0)
         filename = fdt_util.GetString(self._node, 'filename')
         if filename:
             self._filename = filename

tools/binman/ftest.py

@@ -4496,6 +4496,18 @@ class TestFunctional(unittest.TestCase):
                          section + tools.GetBytes(0xfe, 3) + U_BOOT_DATA,
                          data)
 
+    def testAlignDefault(self):
+        """Test that default alignment works on sections"""
+        data = self._DoReadFile('200_align_default.dts')
+        expected = (U_BOOT_DATA + tools.GetBytes(0, 8 - len(U_BOOT_DATA)) +
+                    U_BOOT_DATA)
+        # Special alignment for section
+        expected += tools.GetBytes(0, 32 - len(expected))
+        # No alignment within the nested section
+        expected += U_BOOT_DATA + U_BOOT_NODTB_DATA;
+        # Now the final piece, which should be default-aligned
+        expected += tools.GetBytes(0, 88 - len(expected)) + U_BOOT_NODTB_DATA
+        self.assertEqual(expected, data)
 
 if __name__ == "__main__":
     unittest.main()

tools/binman/test/200_align_default.dts

@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/dts-v1/;
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	binman {
+		align-default = <8>;
+		u-boot {
+		};
+
+		u-boot-align {
+			type = "u-boot";
+		};
+
+		section {
+			align = <32>;
+			u-boot {
+			};
+
+			u-boot-nodtb {
+			};
+		};
+
+		u-boot-nodtb {
+		};
+	};
+};