| /* |
| * 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); |