binman: Support reading an image with entry args

Normally when an entry is created, any entry arguments it has are required
to be provided, so it can actually generate its contents correctly.

However when an existing image is read, Entry objects are created for each
of the entries in the image. This happens as part of the process of
reading the image into binman.

In this case we don't need the entry arguments, since we do not intend to
regenerate the entries, or at least not unless requested. So there is no
sense in reporting an error for missing entry arguments.

Add a new property for the Image to handle this case. Update the error
reporting to be conditional on this property.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/binman/entry.py b/tools/binman/entry.py
index 2be0d8e..d58a730 100644
--- a/tools/binman/entry.py
+++ b/tools/binman/entry.py
@@ -434,8 +434,7 @@
                 missing.append(prop.name)
             values.append(value)
         if missing:
-            self.Raise('Missing required properties/entry args: %s' %
-                       (', '.join(missing)))
+            self.GetImage().MissingArgs(self, missing)
         return values
 
     def GetPath(self):
diff --git a/tools/binman/etype/section.py b/tools/binman/etype/section.py
index 9c6334c..28a8887 100644
--- a/tools/binman/etype/section.py
+++ b/tools/binman/etype/section.py
@@ -679,3 +679,18 @@
             for entry in to_add.values():
                 self._CollectEntries(entries, entries_by_name, entry)
         entries_by_name[add_entry.name] = add_entry
+
+    def MissingArgs(self, entry, missing):
+        """Report a missing argument, if enabled
+
+        For entries which require arguments, this reports an error if some are
+        missing. If missing entries are being ignored (e.g. because we read the
+        entry from an image rather than creating it), this function does
+        nothing.
+
+        Args:
+            missing: List of missing properties / entry args, each a string
+        """
+        if not self._ignore_missing:
+            entry.Raise('Missing required properties/entry args: %s' %
+                       (', '.join(missing)))
diff --git a/tools/binman/ftest.py b/tools/binman/ftest.py
index 5016060..8b928eb 100644
--- a/tools/binman/ftest.py
+++ b/tools/binman/ftest.py
@@ -4154,6 +4154,25 @@
                     U_BOOT_SPL_DATA[20:])
         self.assertEqual(expected, data)
 
+    def testReadImageEntryArg(self):
+        """Test reading an image that would need an entry arg to generate"""
+        entry_args = {
+            'cros-ec-rw-path': 'ecrw.bin',
+        }
+        data = self.data = self._DoReadFileDtb(
+            '188_image_entryarg.dts',use_real_dtb=True, update_dtb=True,
+            entry_args=entry_args)
+
+        image_fname = tools.GetOutputFilename('image.bin')
+        orig_image = control.images['image']
+
+        # This should not generate an error about the missing 'cros-ec-rw-path'
+        # since we are reading the image from a file. Compare with
+        # testEntryArgsRequired()
+        image = Image.FromFile(image_fname)
+        self.assertEqual(orig_image.GetEntries().keys(),
+                         image.GetEntries().keys())
+
 
 if __name__ == "__main__":
     unittest.main()
diff --git a/tools/binman/image.py b/tools/binman/image.py
index 3622efc..3c2fe5e 100644
--- a/tools/binman/image.py
+++ b/tools/binman/image.py
@@ -43,8 +43,13 @@
         test: True if this is being called from a test of Images. This this case
             there is no device tree defining the structure of the section, so
             we create a section manually.
+        ignore_missing: Ignore any missing entry arguments (i.e. don't raise an
+            exception). This should be used if the Image is being loaded from
+            a file rather than generated. In that case we obviously don't need
+            the entry arguments since the contents already exists.
     """
-    def __init__(self, name, node, copy_to_orig=True, test=False):
+    def __init__(self, name, node, copy_to_orig=True, test=False,
+                 ignore_missing=False):
         super().__init__(None, 'section', node, test=test)
         self.copy_to_orig = copy_to_orig
         self.name = 'main-section'
@@ -53,6 +58,7 @@
         self.fdtmap_dtb = None
         self.fdtmap_data = None
         self.allow_repack = False
+        self._ignore_missing = ignore_missing
         if not test:
             self.ReadNode()
 
@@ -100,7 +106,7 @@
 
         # Return an Image with the associated nodes
         root = dtb.GetRoot()
-        image = Image('image', root, copy_to_orig=False)
+        image = Image('image', root, copy_to_orig=False, ignore_missing=True)
 
         image.image_node = fdt_util.GetString(root, 'image-node', 'image')
         image.fdtmap_dtb = dtb
diff --git a/tools/binman/test/188_image_entryarg.dts b/tools/binman/test/188_image_entryarg.dts
new file mode 100644
index 0000000..29d8149
--- /dev/null
+++ b/tools/binman/test/188_image_entryarg.dts
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/dts-v1/;
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	binman {
+		size = <0xc00>;
+		u-boot {
+		};
+		cros-ec-rw {
+		};
+		fdtmap {
+		};
+		image-header {
+			location = "end";
+		};
+	};
+};