/* * 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, 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; 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);