dtoc: Support reading a list of arguments

It is helpful to support a string or stringlist containing a list of
space-separated arguments, for example:

   args = "-n fred", "-a", "123";

This resolves to the list:

   -n fred -a 123

which can be passed to a program as arguments.

Add a helper to do the required processing.

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

tools/dtoc/fdt_util.py

@@ -184,6 +184,18 @@ def GetStringList(node, propname, default=None):
         return [strval]
     return value
 
+def GetArgs(node, propname):
+    prop = node.props.get(propname)
+    if not prop:
+        raise ValueError(f"Node '{node.path}': Expected property '{propname}'")
+    if prop.bytes:
+        value = GetStringList(node, propname)
+    else:
+        value = []
+    lists = [v.split() for v in value]
+    args = [x for l in lists for x in l]
+    return args
+
 def GetBool(node, propname, default=False):
     """Get an boolean from a property
 

tools/dtoc/test/dtoc_test_simple.dts

@@ -62,5 +62,6 @@
 
 	orig-node {
 		orig = <1 23 4>;
+		args = "-n first", "second", "-p", "123,456", "-x";
 	};
 };

tools/dtoc/test_fdt.py

@@ -652,6 +652,21 @@ class TestFdtUtil(unittest.TestCase):
         self.assertEqual(['test'],
                          fdt_util.GetStringList(self.node, 'missing', ['test']))
 
+    def testGetArgs(self):
+        node = self.dtb.GetNode('/orig-node')
+        self.assertEqual(['message'], fdt_util.GetArgs(self.node, 'stringval'))
+        self.assertEqual(
+            ['multi-word', 'message'],
+            fdt_util.GetArgs(self.node, 'stringarray'))
+        self.assertEqual([], fdt_util.GetArgs(self.node, 'boolval'))
+        self.assertEqual(['-n', 'first', 'second', '-p', '123,456', '-x'],
+                         fdt_util.GetArgs(node, 'args'))
+        with self.assertRaises(ValueError) as exc:
+            fdt_util.GetArgs(self.node, 'missing')
+        self.assertIn(
+            "Node '/spl-test': Expected property 'missing'",
+            str(exc.exception))
+
     def testGetBool(self):
         self.assertEqual(True, fdt_util.GetBool(self.node, 'boolval'))
         self.assertEqual(False, fdt_util.GetBool(self.node, 'missing'))