binman: Support building a selection of images

Sometimes it is useful to build only a subset of the images provided by
the binman configuration. Add a -i option for this. It can be given
multiple times to build several images. If the option is not given, all
images are built.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/binman/cmdline.py b/tools/binman/cmdline.py
index f0de4de..4ce8bc6 100644
--- a/tools/binman/cmdline.py
+++ b/tools/binman/cmdline.py
@@ -30,6 +30,8 @@
             help='Enabling debugging (provides a full traceback on error)')
     parser.add_option('-E', '--entry-docs', action='store_true',
             help='Write out entry documentation (see README.entries)')
+    parser.add_option('-i', '--image', type='string', action='append',
+            help='Image filename to build (if not specified, build all)')
     parser.add_option('-I', '--indir', action='append',
             help='Add a path to a directory to use for input files')
     parser.add_option('-H', '--full-help', action='store_true',
diff --git a/tools/binman/control.py b/tools/binman/control.py
index 2de1c86..8c48008 100644
--- a/tools/binman/control.py
+++ b/tools/binman/control.py
@@ -162,6 +162,15 @@
 
             images = _ReadImageDesc(node)
 
+            if options.image:
+                skip = []
+                for name, image in images.iteritems():
+                    if name not in options.image:
+                        del images[name]
+                        skip.append(name)
+                if skip:
+                    print 'Skipping images: %s\n' % ', '.join(skip)
+
             # Prepare the device tree by making sure that any missing
             # properties are added (e.g. 'pos' and 'size'). The values of these
             # may not be correct yet, but we add placeholders so that the
diff --git a/tools/binman/ftest.py b/tools/binman/ftest.py
index c406555..290e9ae 100644
--- a/tools/binman/ftest.py
+++ b/tools/binman/ftest.py
@@ -171,7 +171,7 @@
         return control.Binman(options, args)
 
     def _DoTestFile(self, fname, debug=False, map=False, update_dtb=False,
-                    entry_args=None):
+                    entry_args=None, images=None):
         """Run binman with a given test file
 
         Args:
@@ -180,6 +180,10 @@
             map: True to output map files for the images
             update_dtb: Update the offset and size of each entry in the device
                 tree before packing it into the image
+            entry_args: Dict of entry args to supply to binman
+                key: arg name
+                value: value of that arg
+            images: List of image names to build
         """
         args = ['-p', '-I', self._indir, '-d', self.TestFile(fname)]
         if debug:
@@ -191,6 +195,9 @@
         if entry_args:
             for arg, value in entry_args.iteritems():
                 args.append('-a%s=%s' % (arg, value))
+        if images:
+            for image in images:
+                args += ['-i', image]
         return self._DoBinman(*args)
 
     def _SetupDtb(self, fname, outfile='u-boot.dtb'):
@@ -1384,6 +1391,16 @@
         data = self._DoReadFile('81_x86-start16-tpl.dts')
         self.assertEqual(X86_START16_TPL_DATA, data[:len(X86_START16_TPL_DATA)])
 
+    def testSelectImage(self):
+        """Test that we can select which images to build"""
+        with test_util.capture_sys_output() as (stdout, stderr):
+            retcode = self._DoTestFile('06_dual_image.dts', images=['image2'])
+        self.assertEqual(0, retcode)
+        self.assertIn('Skipping images: image1', stdout.getvalue())
+
+        self.assertFalse(os.path.exists(tools.GetOutputFilename('image1.bin')))
+        self.assertTrue(os.path.exists(tools.GetOutputFilename('image2.bin')))
+
 
 if __name__ == "__main__":
     unittest.main()