binman: Add 'min-size' entry property

This property sets the minimum size of an entry, including padding but
not alignment. It can be used to reserve space for growth of an entry,
or to enforce a minimum offset for later entries in the section.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Simon Glass <sjg@chromium.org>

tools/binman/binman.rst

@@ -615,6 +615,14 @@ size:
     this size. If this is not provided, it will be set to the size of the
     contents.
 
+min-size:
+    Sets the minimum size of the entry. This size includes explicit padding
+    ('pad-before' and 'pad-after'), but not padding added to meet alignment
+    requirements. While this does not affect the contents of the entry within
+    binman itself (the padding is performed only when its parent section is
+    assembled), the end result will be that the entry ends with the padding
+    bytes, so may grow. Defaults to 0.
+
 pad-before:
     Padding before the contents of the entry. Normally this is 0, meaning
     that the contents start at the beginning of the entry. This can be used

tools/binman/entry.py

@@ -49,6 +49,7 @@ class Entry(object):
         offset: Offset of entry within the section, None if not known yet (in
             which case it will be calculated by Pack())
         size: Entry size in bytes, None if not known
+        min_size: Minimum entry size in bytes
         pre_reset_size: size as it was before ResetForPack(). This allows us to
             keep track of the size we started with and detect size changes
         uncomp_size: Size of uncompressed data in bytes, if the entry is
@@ -114,6 +115,7 @@ class Entry(object):
         self.name = node and (name_prefix + node.name) or 'none'
         self.offset = None
         self.size = None
+        self.min_size = 0
         self.pre_reset_size = None
         self.uncomp_size = None
         self.data = None
@@ -270,6 +272,7 @@ class Entry(object):
             self.Raise("Please use 'extend-size' instead of 'expand-size'")
         self.offset = fdt_util.GetInt(self._node, 'offset')
         self.size = fdt_util.GetInt(self._node, 'size')
+        self.min_size = fdt_util.GetInt(self._node, 'min-size', 0)
         self.orig_offset = fdt_util.GetInt(self._node, 'orig-offset')
         self.orig_size = fdt_util.GetInt(self._node, 'orig-size')
         if self.GetImage().copy_to_orig:
@@ -507,6 +510,7 @@ class Entry(object):
             else:
                 self.offset = tools.align(offset, self.align)
         needed = self.pad_before + self.contents_size + self.pad_after
+        needed = max(needed, self.min_size)
         needed = tools.align(needed, self.align_size)
         size = self.size
         if not size:

tools/binman/ftest.py

@@ -883,9 +883,9 @@ class TestFunctional(unittest.TestCase):
         self.assertIn('image', control.images)
         image = control.images['image']
         entries = image.GetEntries()
-        self.assertEqual(5, len(entries))
+        self.assertEqual(6, len(entries))
 
-        # First u-boot with padding before and after
+        # First u-boot with padding before and after (included in minimum size)
         self.assertIn('u-boot', entries)
         entry = entries['u-boot']
         self.assertEqual(0, entry.offset)
@@ -934,8 +934,17 @@ class TestFunctional(unittest.TestCase):
         self.assertEqual(U_BOOT_DATA + tools.get_bytes(0, 64 - len(U_BOOT_DATA)),
                          data[pos:pos + entry.size])
 
+        # Sixth u-boot with both minimum size and aligned size
+        self.assertIn('u-boot-min-size', entries)
+        entry = entries['u-boot-min-size']
+        self.assertEqual(128, entry.offset)
+        self.assertEqual(32, entry.size)
+        self.assertEqual(U_BOOT_DATA, entry.data[:len(U_BOOT_DATA)])
+        self.assertEqual(U_BOOT_DATA + tools.get_bytes(0, 32 - len(U_BOOT_DATA)),
+                         data[pos:pos + entry.size])
+
         self.CheckNoGaps(entries)
-        self.assertEqual(128, image.size)
+        self.assertEqual(160, image.size)
 
         dtb = fdt.Fdt(out_dtb_fname)
         dtb.Scan()
@@ -943,7 +952,7 @@ class TestFunctional(unittest.TestCase):
         expected = {
             'image-pos': 0,
             'offset': 0,
-            'size': 128,
+            'size': 160,
 
             'u-boot:image-pos': 0,
             'u-boot:offset': 0,
@@ -964,6 +973,10 @@ class TestFunctional(unittest.TestCase):
             'u-boot-align-both:image-pos': 64,
             'u-boot-align-both:offset': 64,
             'u-boot-align-both:size': 64,
+
+            'u-boot-min-size:image-pos': 128,
+            'u-boot-min-size:offset': 128,
+            'u-boot-min-size:size': 32,
             }
         self.assertEqual(expected, props)
 

tools/binman/test/009_pack_extra.dts

@@ -6,6 +6,7 @@
 
 	binman {
 		u-boot {
+			min-size = <12>;
 			pad-before = <3>;
 			pad-after = <5>;
 		};
@@ -31,5 +32,11 @@
 			align = <64>;
 			align-end = <128>;
 		};
+
+		u-boot-min-size {
+			type = "u-boot";
+			min-size = <24>;
+			align-size = <16>;
+		};
 	};
 };