fs: ubifs: Implement Linux rootarg

Add the parameter to boot from ubifs fileystems. This assumes that
there will be only one UBI device registered in the kernel, otherwise
there is no way to predict the ubi number.

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

1 files changed, 23 insertions, 0 deletions

diff --git a/fs/ubifs/ubifs.c b/fs/ubifs/ubifs.c
index 68d90b36e7..a9189f76b5 100644
--- a/fs/ubifs/ubifs.c
+++ b/fs/ubifs/ubifs.c
@@ -36,6 +36,7 @@
 #include <linux/zlib.h>
 #include <xfuncs.h>
 #include <fcntl.h>
+#include <linux/mtd/mtd.h>
 
 #include "ubifs.h"
 
@@ -584,6 +585,26 @@ static int ubifs_readlink(struct device_d *dev, const char *pathname, char *buf,
 	return 0;
 }
 
+static void ubifs_set_rootarg(struct ubifs_priv *priv, struct fs_device_d *fsdev)
+{
+	struct ubi_volume_info vi = {};
+	struct ubi_device_info di = {};
+	struct mtd_info *mtd;
+	char *str;
+
+	ubi_get_volume_info(priv->ubi, &vi);
+	ubi_get_device_info(vi.ubi_num, &di);
+
+	mtd = di.mtd;
+
+	str = asprintf("root=ubi0:%s ubi.mtd=%s rootfstype=ubifs",
+			vi.name, mtd->cdev.partname);
+
+	fsdev_set_linux_rootarg(fsdev, str);
+
+	free(str);
+}
+
 static int ubifs_probe(struct device_d *dev)
 {
 	struct fs_device_d *fsdev = dev_to_fs_device(dev);
@@ -612,6 +633,8 @@ static int ubifs_probe(struct device_d *dev)
 		goto err;
 	}
 
+	ubifs_set_rootarg(priv, fsdev);
+
 	return 0;
 err:
 	ubi_close_volume(priv->ubi);