[PATCH 5/6] fs: squashfs: append linux rootarg for ubi volume

[Sascha Hauer]

From: Enrico Jorns <ejo at pengutronix.de>

If squashfs runs from an ubi volume, append appropriate root kernel
options.

Note that ubiblock support is required in the kernel for that.

Signed-off-by: Enrico Jorns <ejo at pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 fs/squashfs/squashfs.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/fs/squashfs/squashfs.c b/fs/squashfs/squashfs.c
index 6d04681..c4d0bac 100644
--- a/fs/squashfs/squashfs.c
+++ b/fs/squashfs/squashfs.c
@@ -9,12 +9,16 @@
 #include <linux/fs.h>
 #include <linux/stat.h>
 #include <linux/pagemap.h>
+#include <linux/mtd/ubi.h>
+#include <linux/mtd/mtd.h>
 
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"
 #include "squashfs_fs_i.h"
 #include "squashfs.h"
 
+struct ubi_volume_desc;
+
 char *squashfs_devread(struct squashfs_sb_info *fs, int byte_offset,
 		int byte_len)
 {
@@ -108,6 +112,31 @@ static struct inode *squashfs_findfile(struct super_block *sb,
 	return NULL;
 }
 
+void squashfs_set_rootarg(struct squashfs_priv *priv, struct fs_device_d *fsdev)
+{
+	struct ubi_volume_desc *ubi_vol;
+	struct ubi_volume_info vi = {};
+	struct ubi_device_info di = {};
+	struct mtd_info *mtd;
+	char *str;
+
+	ubi_vol = ubi_open_volume_cdev(fsdev->cdev, UBI_READONLY);
+
+	if (IS_ERR(ubi_vol))
+		return;
+
+	ubi_get_volume_info(ubi_vol, &vi);
+	ubi_get_device_info(vi.ubi_num, &di);
+	mtd = di.mtd;
+
+	str = basprintf("root=/dev/ubiblock%d_%d ubi.mtd=%s ubi.block=%d,%d rootfstype=squashfs",
+			vi.ubi_num, vi.vol_id, mtd->cdev.partname, vi.ubi_num, vi.vol_id);
+
+	fsdev_set_linux_rootarg(fsdev, str);
+
+	free(str);
+}
+
 static int squashfs_probe(struct device_d *dev)
 {
 	struct fs_device_d *fsdev;
@@ -130,6 +159,8 @@ static int squashfs_probe(struct device_d *dev)
 		goto err_out;
 	}
 
+	squashfs_set_rootarg(priv, fsdev);
+
 	return 0;
 
 err_out:
-- 
2.9.3