| b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame^] | 1 | #!/usr/bin/env python3 |
| 2 | """ |
| 3 | # SPDX-License-Identifier: GPL-2.0-or-later |
| 4 | # |
| 5 | # sercomm-kernel-header.py: Creates Sercomm kernel header |
| 6 | # |
| 7 | # Copyright © 2022 Mikhail Zhilkin |
| 8 | """ |
| 9 | |
| 10 | import argparse |
| 11 | import binascii |
| 12 | import os |
| 13 | import struct |
| 14 | |
| 15 | KERNEL_HEADER_SIZE = 0x100 |
| 16 | PADDING = 0xff |
| 17 | ROOTFS_FAKE_HEADER = "UBI#" |
| 18 | |
| 19 | def auto_int(x): |
| 20 | return int(x, 0) |
| 21 | |
| 22 | def create_kernel_header(args): |
| 23 | out_file = open(args.header_file, "wb") |
| 24 | header = get_kernel_header(args) |
| 25 | out_file.write(header) |
| 26 | out_file.close() |
| 27 | |
| 28 | def get_kernel_header(args): |
| 29 | header = bytearray([PADDING] * KERNEL_HEADER_SIZE) |
| 30 | |
| 31 | struct.pack_into('<L', header, 0xc, 0xffffff02) |
| 32 | struct.pack_into('<L', header, 0x1c, 0x0) |
| 33 | struct.pack_into('<L', header, 0x34, 0x0) |
| 34 | struct.pack_into('<L', header, 0x10, args.kernel_offset) |
| 35 | struct.pack_into('<L', header, 0x28, args.rootfs_offset) |
| 36 | |
| 37 | if (args.rootfs_file): |
| 38 | if (args.rootfs_checking_size): |
| 39 | rootfs_size = args.rootfs_checking_size |
| 40 | else: |
| 41 | rootfs_size = os.path.getsize(args.rootfs_file) |
| 42 | buf = open(args.rootfs_file,'rb').read(rootfs_size) |
| 43 | crc = binascii.crc32(buf) & 0xffffffff |
| 44 | else: |
| 45 | rootfs_size = len(ROOTFS_FAKE_HEADER) |
| 46 | crc = binascii.crc32(str.encode(ROOTFS_FAKE_HEADER)) & \ |
| 47 | 0xffffffff |
| 48 | struct.pack_into('<L', header, 0x2c, rootfs_size) |
| 49 | struct.pack_into('<L', header, 0x30, crc) |
| 50 | |
| 51 | kernel_size = os.path.getsize(args.kernel_file) |
| 52 | struct.pack_into('<L', header, 0x14, kernel_size) |
| 53 | |
| 54 | kernel_end_offset = args.kernel_offset + kernel_size |
| 55 | struct.pack_into('<L', header, 0x4, kernel_end_offset) |
| 56 | |
| 57 | buf = open(args.kernel_file,'rb').read() |
| 58 | crc = binascii.crc32(buf) & 0xffffffff |
| 59 | struct.pack_into('<L', header, 0x18, crc) |
| 60 | |
| 61 | crc = binascii.crc32(header) & 0xffffffff |
| 62 | struct.pack_into('<L', header, 0x8, crc) |
| 63 | |
| 64 | struct.pack_into('<L', header, 0x0, 0x726553) |
| 65 | |
| 66 | return header |
| 67 | |
| 68 | def main(): |
| 69 | global args |
| 70 | |
| 71 | parser = argparse.ArgumentParser(description='This script generates \ |
| 72 | a kernel header for the Sercomm mt7621 devices') |
| 73 | |
| 74 | parser.add_argument('--kernel-image', |
| 75 | dest='kernel_file', |
| 76 | action='store', |
| 77 | type=str, |
| 78 | help='Path to a Kernel binary image') |
| 79 | |
| 80 | parser.add_argument('--kernel-offset', |
| 81 | dest='kernel_offset', |
| 82 | action='store', |
| 83 | type=auto_int, |
| 84 | help='Kernel offset') |
| 85 | |
| 86 | parser.add_argument('--rootfs-offset', |
| 87 | dest='rootfs_offset', |
| 88 | action='store', |
| 89 | type=auto_int, |
| 90 | help='RootFS offset') |
| 91 | |
| 92 | parser.add_argument('--output-header', |
| 93 | dest='header_file', |
| 94 | action='store', |
| 95 | type=str, |
| 96 | help='Output kernel header file') |
| 97 | |
| 98 | parser.add_argument('--rootfs-image', |
| 99 | dest='rootfs_file', |
| 100 | action='store', |
| 101 | type=str, |
| 102 | help='Path to RootFS binary image (optional)') |
| 103 | |
| 104 | parser.add_argument('--rootfs-checking-size', |
| 105 | dest='rootfs_checking_size', |
| 106 | action='store', |
| 107 | type=auto_int, |
| 108 | help='Bytes count for CRC calculation (optional)') |
| 109 | |
| 110 | args = parser.parse_args() |
| 111 | |
| 112 | if ((not args.kernel_file) or |
| 113 | (not args.kernel_offset) or |
| 114 | (not args.rootfs_offset) or |
| 115 | (not args.header_file)): |
| 116 | parser.print_help() |
| 117 | exit() |
| 118 | |
| 119 | create_kernel_header(args) |
| 120 | |
| 121 | main() |