bbu: Allow to refresh/repair images

Some SoCs allow to store multiple boot images on a device in order to
improve robustness. This adds a -r option to barebox_update to indicate
we do not want to make an update but instead repair/refresh an existing
image. Handlers which want to support this feature must set the
BBU_HANDLER_CAN_REFRESH flag during registration.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Documentation/user/updating.rst

@@ -30,3 +30,11 @@ commands. The exact commands are board specific.
 
 **NOTE** barebox images can be enriched with metadata which can be used to check
 if a given image is suitable for updating barebox, see :ref:`imd`.
+
+Repairing existing boot images
+------------------------------
+
+Some SoCs allow to store multiple boot images on a device in order to
+improve robustness. When an update handler supports it the handler can
+repair and/or refresh an image from this redundant information. This is
+done with the '-r' option to :ref:`command_barebox_update`.

commands/barebox-update.c

@@ -26,10 +26,10 @@
 
 static int do_barebox_update(int argc, char *argv[])
 {
-	int opt, ret;
+	int opt, ret, repair = 0;
 	struct bbu_data data = {};
 
-	while ((opt = getopt(argc, argv, "t:yf:ld:")) > 0) {
+	while ((opt = getopt(argc, argv, "t:yf:ld:r")) > 0) {
 		switch (opt) {
 		case 'd':
 			data.devicefile = optarg;
@@ -48,19 +48,24 @@ static int do_barebox_update(int argc, char *argv[])
 			printf("registered update handlers:\n");
 			bbu_handlers_list();
 			return 0;
+		case 'r':
+			repair = 1;
+			break;
 		default:
 			return COMMAND_ERROR_USAGE;
 		}
 	}
 
-	if (!(argc - optind))
-		return COMMAND_ERROR_USAGE;
+	if (argc - optind > 0) {
+		data.imagefile = argv[optind];
 
-	data.imagefile = argv[optind];
-
-	data.image = read_file(data.imagefile, &data.len);
-	if (!data.image)
-		return -errno;
+		data.image = read_file(data.imagefile, &data.len);
+		if (!data.image)
+			return -errno;
+	} else {
+		if (!repair)
+			return COMMAND_ERROR_USAGE;
+	}
 
 	ret = barebox_update(&data);
 
@@ -74,6 +79,7 @@ BAREBOX_CMD_HELP_TEXT("Options:")
 BAREBOX_CMD_HELP_OPT("-l\t", "list registered targets")
 BAREBOX_CMD_HELP_OPT("-t TARGET", "specify data target handler name")
 BAREBOX_CMD_HELP_OPT("-d DEVICE", "write image to DEVICE")
+BAREBOX_CMD_HELP_OPT("-r\t", "refresh or repair. Do not update, but repair an existing image")
 BAREBOX_CMD_HELP_OPT("-y\t", "autom. use 'yes' when asking confirmations")
 BAREBOX_CMD_HELP_OPT("-f LEVEL", "set force level")
 BAREBOX_CMD_HELP_END
@@ -81,7 +87,7 @@ BAREBOX_CMD_HELP_END
 BAREBOX_CMD_START(barebox_update)
 	.cmd		= do_barebox_update,
 	BAREBOX_CMD_DESC("update barebox to persistent media")
-	BAREBOX_CMD_OPTS("[-ltdyf] [IMAGE]")
+	BAREBOX_CMD_OPTS("[-ltdyfr] [IMAGE]")
 	BAREBOX_CMD_GROUP(CMD_GRP_MISC)
 	BAREBOX_CMD_HELP(cmd_barebox_update_help)
 BAREBOX_CMD_END

common/bbu.c

@@ -65,9 +65,13 @@ int bbu_confirm(struct bbu_data *data)
 	if (data->flags & BBU_FLAG_YES)
 		return 0;
 
-	printf("update barebox from %s using handler %s to %s (y/n)?\n",
+	if (data->imagefile)
+		printf("update barebox from %s using handler %s to %s (y/n)?\n",
 			data->imagefile, data->handler_name,
 			data->devicefile);
+	else
+		printf("Refresh barebox on %s using handler %s (y/n)?\n",
+			data->devicefile, data->handler_name);
 
 	key = read_key();
 
@@ -141,6 +145,12 @@ int barebox_update(struct bbu_data *data)
 	if (!handler)
 		return -ENODEV;
 
+	if (!data->image && !data->imagefile &&
+	    !(handler->flags & BBU_HANDLER_CAN_REFRESH)) {
+		pr_err("No Image file given\n");
+		return -EINVAL;
+	}
+
 	if (!data->handler_name)
 		data->handler_name = handler->name;
 

include/bbu.h

@@ -23,6 +23,7 @@ struct bbu_handler {
 	const char *name;
 	struct list_head list;
 #define BBU_HANDLER_FLAG_DEFAULT	(1 << 0)
+#define BBU_HANDLER_CAN_REFRESH		(1 << 1)
 	unsigned long flags;
 
 	/* default device file, can be overwritten on the command line */