1 files changed, 116 insertions, 0 deletions
diff --git a/target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit.c b/target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit.c
new file mode 100644
index 0000000..162739f
--- /dev/null
+++ b/target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit.c
@@ -0,0 +1,116 @@
+/*
+ * Copyright (C) 2009-2013 Felix Fietkau <nbd@openwrt.org>
+ * Copyright (C) 2009-2013 Gabor Juhos <juhosg@openwrt.org>
+ * Copyright (C) 2012 Jonas Gorski <jogo@openwrt.org>
+ * Copyright (C) 2013 Hauke Mehrtens <hauke@hauke-m.de>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ */
+
+#define pr_fmt(fmt)	"mtdsplit: " fmt
+
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/magic.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/byteorder/generic.h>
+
+#include "mtdsplit.h"
+
+struct squashfs_super_block {
+	__le32 s_magic;
+	__le32 pad0[9];
+	__le64 bytes_used;
+};
+
+int mtd_get_squashfs_len(struct mtd_info *master,
+			 size_t offset,
+			 size_t *squashfs_len)
+{
+	struct squashfs_super_block sb;
+	size_t retlen;
+	int err;
+
+	err = mtd_read(master, offset, sizeof(sb), &retlen, (void *)&sb);
+	if (err || (retlen != sizeof(sb))) {
+		pr_alert("error occured while reading from \"%s\"\n",
+			 master->name);
+		return -EIO;
+	}
+
+	if (le32_to_cpu(sb.s_magic) != SQUASHFS_MAGIC) {
+		pr_alert("no squashfs found in \"%s\"\n", master->name);
+		return -EINVAL;
+	}
+
+	retlen = le64_to_cpu(sb.bytes_used);
+	if (retlen <= 0) {
+		pr_alert("squashfs is empty in \"%s\"\n", master->name);
+		return -ENODEV;
+	}
+
+	if (offset + retlen > master->size) {
+		pr_alert("squashfs has invalid size in \"%s\"\n",
+			 master->name);
+		return -EINVAL;
+	}
+
+	*squashfs_len = retlen;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mtd_get_squashfs_len);
+
+static ssize_t mtd_next_eb(struct mtd_info *mtd, size_t offset)
+{
+	return mtd_rounddown_to_eb(offset, mtd) + mtd->erasesize;
+}
+
+int mtd_check_rootfs_magic(struct mtd_info *mtd, size_t offset)
+{
+	u32 magic;
+	size_t retlen;
+	int ret;
+
+	ret = mtd_read(mtd, offset, sizeof(magic), &retlen,
+		       (unsigned char *) &magic);
+	if (ret)
+		return ret;
+
+	if (retlen != sizeof(magic))
+		return -EIO;
+
+	if (le32_to_cpu(magic) != SQUASHFS_MAGIC &&
+	    magic != 0x19852003)
+		return -EINVAL;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mtd_check_rootfs_magic);
+
+int mtd_find_rootfs_from(struct mtd_info *mtd,
+			 size_t from,
+			 size_t limit,
+			 size_t *ret_offset)
+{
+	size_t offset;
+	int err;
+
+	for (offset = from; offset < limit;
+	     offset = mtd_next_eb(mtd, offset)) {
+		err = mtd_check_rootfs_magic(mtd, offset);
+		if (err)
+			continue;
+
+		*ret_offset = offset;
+		return 0;
+	}
+
+	return -ENODEV;
+}
+EXPORT_SYMBOL_GPL(mtd_find_rootfs_from);
+