openwrt/target/linux/mediatek/image/gen_mtk_mmc_img.sh

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#!/bin/sh
#
# Copyright © 2019 Alexey Loukianov <lx2@lexa2.ru>
# Copyright © 2020 David Woodhouse <dwmw2@infradead.org>
#
# This is free software, licensed under the GNU General Public License v2.
# See /LICENSE for more information.
#
# Generates a bootable SD card image for Banana Pi R2 (and probably
# other similar boards) as documented at
# http://www.fw-web.de/dokuwiki/doku.php?id=en:bpi-r2:storage
#
# The first sector must contain the SDMMC_BOOT header shown
# below, and also contains the MBR partition table in the end
# of the sector. The partition table must contain no active
# partitions.
#
# The second sector must contain the BRLYT header, and the
# special preloader image goes in sector 4; 2KiB into the image.
#
# The preloader loads U-Boot from sector 640; 320KiB into the image.
# The location and the size (512KiB) are fixed and not read from
# the partition table. We set up a partition for it merely for
# our own convenience for upgrades, etc.
#
# The second partition is a FAT file system containing the kernel
# image and a uboot.env file, which is provided to this script as
# $4 (bootfs image). Its size is configurable with the
# CONFIG_MTK_BOOT_PARTSIZE option; by default 32MiB.
#
# The root filesystem comes next in the third partition.
#
#
# ------------------------ Sector Offset
# | MBR + SDMMC_BOOT | 0 0x0
# |----------------------|
# | BRLYT header | 1 0x200
# |----------------------|
# . .
# . .
# |----------------------|
# | | 4 0x800
# | |
# | Preloader |
# . .
# . .
# | | 639
# |----------------------|
# | MBR partition #1 | 640 0x50000
# | |
# | U-Boot |
# . .
# . .
# | | 1663
# |----------------------|
# | MBR partition #2 |
# | |
# | FAT partition | ( MTK_BOOT_PARTSIZE
# . . default 32MiB )
# . (kernel, uEnv) .
# | |
# |----------------------|
# | MBR partition #3 |
# | |
# | Root partition |
# | | ( TARGET_ROOTFS_PARTSIZE
# | (squashfs+overlay | default 104MiB )
# . or ext4, etc.) .
# . .
# | |
# ------------------------
#
# For eMMC boot, everything up to and including the preloader must be
# written to /dev/mmcblk0boot0, with the SDMMC_BOOT header changed to
# read EMMC_BOOT\0 instead.
#
# The contents of the main eMMC are identical to the SD card layout,
# with the preloader loading 512KiB of U-Boot starting at 0x50000.
usage() {
echo "SYNTAX: $0 sd <file> <preloader image> <u-boot image> <u-boot offset> <bootfs image> <rootfs image> <bootfs size> <rootfs size>"
echo " OR: $0 emmc <file> <preloader image>"
exit 1
}
set -e
PRELOADER_OFFSET=2 # 2KiB
SDMMC_BOOT="SDMMC_BOOT\x00\x00\x01\x00\x00\x00\x00\x02\x00\x00"
EMMC_BOOT="EMMC_BOOT\x00\x00\x00\x01\x00\x00\x00\x00\x02\x00\x00"
BRLYT="BRLYT\x00\x00\x00\x01\x00\x00\x00\x00\x08\x00\x00\
\x00\x08\x00\x00\x42\x42\x42\x42\x08\x00\x01\x00\x00\x08\x00\x00\
\x00\x08\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
case $1 in
sd)
[ $# -eq 9 ] || usage
OUTPUT="$2"
PRELOADER="$3"
UBOOT="$4"
UBOOTOFS="$5"
BOOTFS="$6"
ROOTFS="$7"
BOOTFSSIZE="$8"
ROOTFSSIZE="$9"
head=4
sect=63
set $(ptgen -o $OUTPUT -h $head -s $sect -a 0 -l 1024 \
-t 41 -p 512k@${UBOOTOFS} \
-t c -p ${BOOTFSSIZE}M \
-t 83 -p ${ROOTFSSIZE}M )
UBOOT_OFFSET="$(($1 / 512))"
UBOOT_SIZE="$(($2 / 512))"
BOOTFS_OFFSET="$(($3 / 512))"
BOOTFS_SIZE="$(($4 / 512))"
ROOTFS_OFFSET="$(($5 / 512))"
ROOTFS_SIZE="$(($6 / 512))"
echo -en "${SDMMC_BOOT}" | dd bs=1 of="${OUTPUT}" seek=0 conv=notrunc
echo -en "${BRLYT}" | dd bs=1 of="${OUTPUT}" seek=512 conv=notrunc
# For eMMC-only boards like U7623 the preloader doesn't need to be included in the
# main image as it's only ever needed in the eMMC boot partition.
if [ -r ${PRELOADER} ]; then
dd bs=1024 if="${PRELOADER}" of="${OUTPUT}" seek="${PRELOADER_OFFSET}" conv=notrunc
fi
dd bs=512 if="${UBOOT}" of="${OUTPUT}" seek="${UBOOT_OFFSET}" conv=notrunc
dd bs=512 if="${BOOTFS}" of="${OUTPUT}" seek="${BOOTFS_OFFSET}" conv=notrunc
dd bs=512 if="${ROOTFS}" of="${OUTPUT}" seek="${ROOTFS_OFFSET}" conv=notrunc
dd bs=128k if=/dev/zero of="${OUTPUT}" count=1 oflag=append conv=notrunc
;;
emmc)
[ $# -eq 3 ] || usage
OUTPUT="$2"
PRELOADER="$3"
echo -en "${EMMC_BOOT}" | dd bs=1 of="${OUTPUT}" seek=0
echo -en "${BRLYT}" | dd bs=1 of="${OUTPUT}" seek=512 conv=notrunc
dd bs=1024 if="${PRELOADER}" of="${OUTPUT}" seek="${PRELOADER_OFFSET}" conv=notrunc
;;
*)
usage
;;
esac