commit 9fb70b5f568815cc8057112eb7fda17d7adeda81
author Denton Gentry <dgentry@google.com> Wed Dec 21 21:02:05 2011 -0800
committer Allan Zhang <allanzhang@google.com> Mon May 18 17:01:56 2015 -0700
tree ecddfcb8b484113b20d00e2d093cb6543e7f9853
parent f3e12ff88d79eb7cda67521764b21436ab43b3b5

Allow cmdline root= parameter to take partition names like mtdblock:rootfs

Adapted from http://lists.infradead.org/pipermail/linux-mtd/2010-October/032579.html

Change-Id: Id359d227e5b63a0b25119b5b2180b9384b4fa38c

init/do_mounts.c

diff --git a/init/do_mounts.c b/init/do_mounts.c
index bf6edbf..b2f42b5 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -20,6 +20,7 @@
 #include <linux/nfs_fs.h>
 #include <linux/nfs_fs_sb.h>
 #include <linux/nfs_mount.h>
+#include <linux/mtd/mtd.h>
 
 #include "do_mounts.h"
 
@@ -524,8 +525,18 @@
 
 	if (saved_root_name[0]) {
 		root_device_name = saved_root_name;
-		if (!strncmp(root_device_name, "mtd", 3) ||
-		    !strncmp(root_device_name, "ubi", 3)) {
+		if (!strncmp(root_device_name, "mtdblock:", 9)) {
+			struct mtd_info *mtd = get_mtd_device_nm(root_device_name + 9);
+			if (!IS_ERR(mtd))
+				sprintf(root_device_name, "/dev/mtdblock%d", mtd->index);
+			else {
+				printk(KERN_ERR "VFS: Unable to find mtd \"%s\"\n", root_device_name + 9);
+				printk("List of all partitions:\n");
+				printk_all_partitions();
+				panic("VFS: Unable to mount root fs");
+			}
+		} else if (!strncmp(root_device_name, "mtd", 3) ||
+		           !strncmp(root_device_name, "ubi", 3)) {
 			mount_block_root(root_device_name, root_mountflags);
 			goto out;
 		}