Initial commit

target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_brnimage.c

@@ -0,0 +1,104 @@
+/*
+ *  Copyright (C) 2012 John Crispin <blogic@openwrt.org>
+ *  Copyright (C) 2015 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
+ *
+ *  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.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/byteorder/generic.h>
+
+#include "mtdsplit.h"
+
+#define BRNIMAGE_NR_PARTS	2
+
+#define BRNIMAGE_ALIGN_BYTES	0x400
+#define BRNIMAGE_FOOTER_SIZE	12
+
+#define BRNIMAGE_MIN_OVERHEAD	(BRNIMAGE_FOOTER_SIZE)
+#define BRNIMAGE_MAX_OVERHEAD	(BRNIMAGE_ALIGN_BYTES + BRNIMAGE_FOOTER_SIZE)
+
+static int mtdsplit_parse_brnimage(struct mtd_info *master,
+				const struct mtd_partition **pparts,
+				struct mtd_part_parser_data *data)
+{
+	struct mtd_partition *parts;
+	uint32_t buf;
+	unsigned long rootfs_offset, rootfs_size, kernel_size;
+	size_t len;
+	int ret = 0;
+
+	for (rootfs_offset = 0; rootfs_offset < master->size;
+	     rootfs_offset += BRNIMAGE_ALIGN_BYTES) {
+		ret = mtd_check_rootfs_magic(master, rootfs_offset, NULL);
+		if (!ret)
+			break;
+	}
+
+	if (ret)
+		return ret;
+
+	if (rootfs_offset >= master->size)
+		return -EINVAL;
+
+	ret = mtd_read(master, rootfs_offset - BRNIMAGE_FOOTER_SIZE, 4, &len,
+			(void *)&buf);
+	if (ret)
+		return ret;
+
+	if (len != 4)
+		return -EIO;
+
+	kernel_size = le32_to_cpu(buf);
+
+	if (kernel_size > (rootfs_offset - BRNIMAGE_MIN_OVERHEAD))
+		return -EINVAL;
+
+	if (kernel_size < (rootfs_offset - BRNIMAGE_MAX_OVERHEAD))
+		return -EINVAL;
+
+	/*
+	 * The footer must be untouched as it contains the checksum of the
+	 * original brnImage (kernel + squashfs)!
+	 */
+	rootfs_size = master->size - rootfs_offset - BRNIMAGE_FOOTER_SIZE;
+
+	parts = kzalloc(BRNIMAGE_NR_PARTS * sizeof(*parts), GFP_KERNEL);
+	if (!parts)
+		return -ENOMEM;
+
+	parts[0].name = KERNEL_PART_NAME;
+	parts[0].offset = 0;
+	parts[0].size = kernel_size;
+
+	parts[1].name = ROOTFS_PART_NAME;
+	parts[1].offset = rootfs_offset;
+	parts[1].size = rootfs_size;
+
+	*pparts = parts;
+	return BRNIMAGE_NR_PARTS;
+}
+
+static struct mtd_part_parser mtdsplit_brnimage_parser = {
+	.owner = THIS_MODULE,
+	.name = "brnimage-fw",
+	.parse_fn = mtdsplit_parse_brnimage,
+	.type = MTD_PARSER_TYPE_FIRMWARE,
+};
+
+static int __init mtdsplit_brnimage_init(void)
+{
+	register_mtd_parser(&mtdsplit_brnimage_parser);
+
+	return 0;
+}
+
+subsys_initcall(mtdsplit_brnimage_init);