binman: Add an entry filled with a repeating byte

It is sometimes useful to have an area of the image which is all zeroes,
or all 0xff. This can often be achieved by padding the size of an an
existing entry and setting the pad byte for an entry or image.

But it is useful to have an explicit means of adding blocks of repeating
data to the image. Add a 'fill' entry type to handle this.

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

tools/binman/README.entries

@@ -55,6 +55,22 @@ updating the EC on startup via software sync.
 
 
 
+Entry: fill: An entry which is filled to a particular byte value
+----------------------------------------------------------------
+
+Properties / Entry arguments:
+    - fill-byte: Byte to use to fill the entry
+
+Note that the size property must be set since otherwise this entry does not
+know how large it should be.
+
+You can often achieve the same effect using the pad-byte property of the
+overall image, in that the space between entries will then be padded with
+that byte. But this entry is sometimes useful for explicitly setting the
+byte value of a region.
+
+
+
 Entry: fmap: An entry which contains an Fmap section
 ----------------------------------------------------
 

tools/binman/etype/fill.py

@@ -0,0 +1,32 @@
+# SPDX-License-Identifier: GPL-2.0+
+# Copyright (c) 2018 Google, Inc
+# Written by Simon Glass <sjg@chromium.org>
+#
+
+from entry import Entry
+import fdt_util
+
+
+class Entry_fill(Entry):
+    """An entry which is filled to a particular byte value
+
+    Properties / Entry arguments:
+        - fill-byte: Byte to use to fill the entry
+
+    Note that the size property must be set since otherwise this entry does not
+    know how large it should be.
+
+    You can often achieve the same effect using the pad-byte property of the
+    overall image, in that the space between entries will then be padded with
+    that byte. But this entry is sometimes useful for explicitly setting the
+    byte value of a region.
+    """
+    def __init__(self, section, etype, node):
+        Entry.__init__(self, section, etype, node)
+        if not self.size:
+            self.Raise("'fill' entry must have a size property")
+        self.fill_value = fdt_util.GetByte(self._node, 'fill-byte', 0)
+
+    def ObtainContents(self):
+        self.SetContents(chr(self.fill_value) * self.size)
+        return True

tools/binman/ftest.py

@@ -1235,6 +1235,19 @@ class TestFunctional(unittest.TestCase):
         data, _, _, _ = self._DoReadFileDtb('68_blob_named_by_arg.dts',
                                             entry_args=entry_args)
 
+    def testFill(self):
+        """Test for an fill entry type"""
+        data = self._DoReadFile('69_fill.dts')
+        expected = 8 * chr(0xff) + 8 * chr(0)
+        self.assertEqual(expected, data)
+
+    def testFillNoSize(self):
+        """Test for an fill entry type with no size"""
+        with self.assertRaises(ValueError) as e:
+            self._DoReadFile('70_fill_no_size.dts')
+        self.assertIn("'fill' entry must have a size property",
+                      str(e.exception))
+
 
 if __name__ == "__main__":
     unittest.main()

tools/binman/test/69_fill.dts

@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0+
+/dts-v1/;
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	binman {
+		size = <16>;
+		fill {
+			size = <8>;
+			fill-byte = [ff];
+		};
+	};
+};

tools/binman/test/70_fill_no_size.dts

@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0+
+/dts-v1/;
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	binman {
+		size = <16>;
+		fill {
+			fill-byte = [ff];
+		};
+	};
+};

tools/dtoc/fdt_util.py

@@ -148,6 +148,29 @@ def GetBool(node, propname, default=False):
         return True
     return default
 
+def GetByte(node, propname, default=None):
+    """Get an byte from a property
+
+    Args:
+        node: Node object to read from
+        propname: property name to read
+        default: Default value to use if the node/property do not exist
+
+    Returns:
+        Byte value read, or default if none
+    """
+    prop = node.props.get(propname)
+    if not prop:
+        return default
+    value = prop.value
+    if isinstance(value, list):
+        raise ValueError("Node '%s' property '%s' has list value: expecting "
+                         "a single byte" % (node.name, propname))
+    if len(value) != 1:
+        raise ValueError("Node '%s' property '%s' has length %d, expecting %d" %
+                         (node.name, propname, len(value), 1))
+    return ord(value[0])
+
 def GetDatatype(node, propname, datatype):
     """Get a value of a given type from a property
 

tools/dtoc/test_fdt.py

@@ -380,6 +380,20 @@ class TestFdtUtil(unittest.TestCase):
         self.assertEqual(True, fdt_util.GetBool(self.node, 'missing', True))
         self.assertEqual(False, fdt_util.GetBool(self.node, 'missing', False))
 
+    def testGetByte(self):
+        self.assertEqual(5, fdt_util.GetByte(self.node, 'byteval'))
+        self.assertEqual(3, fdt_util.GetByte(self.node, 'missing', 3))
+
+        with self.assertRaises(ValueError) as e:
+            fdt_util.GetByte(self.node, 'longbytearray')
+        self.assertIn("property 'longbytearray' has list value: expecting a "
+                      'single byte', str(e.exception))
+
+        with self.assertRaises(ValueError) as e:
+            fdt_util.GetByte(self.node, 'intval')
+        self.assertIn("property 'intval' has length 4, expecting 1",
+                      str(e.exception))
+
     def testGetDataType(self):
         self.assertEqual(1, fdt_util.GetDatatype(self.node, 'intval', int))
         self.assertEqual('message', fdt_util.GetDatatype(self.node, 'stringval',
@@ -387,7 +401,6 @@ class TestFdtUtil(unittest.TestCase):
         with self.assertRaises(ValueError) as e:
             self.assertEqual(3, fdt_util.GetDatatype(self.node, 'boolval',
                                                      bool))
-
     def testFdtCellsToCpu(self):
         val = self.node.props['intarray'].value
         self.assertEqual(0, fdt_util.fdt_cells_to_cpu(val, 0))