#!/bin/sh
# Build SD card image

IMAGE="${1}" # For example "boot-bananapi.bin"
DEFCONFIG="${2}" # For example "Bananapi_defconfig"
TUPLE="${3}" # For example "arm-linux-gnueabihf"

set -e

# Create fresh empty directory
TMP=$(mktemp -d tmp.XXXXXX)
cd "${TMP}"

build-image tmp.img
build-u_boot u-boot "${DEFCONFIG}" "${TUPLE}"

# Write Raspberry Pi boot config
cat << EOF > config.txt
kernel=u-boot.bin
boot_delay=0
boot_delay_ms=100
gpu_mem=16
enable_uart=1
EOF

if [ "${TUPLE}" = "aarch64-linux-gnu" ]
then
    echo "arm_64bit=1" >> config.txt
fi

# Download Raspberry Pi boot files
FIRMWARE="https://github.com/raspberrypi/firmware/raw/stable"
wget -nv "${FIRMWARE}/boot/fixup.dat" \
         "${FIRMWARE}/boot/fixup_x.dat" \
         "${FIRMWARE}/boot/fixup_cd.dat" \
         "${FIRMWARE}/boot/fixup_db.dat" \
         "${FIRMWARE}/boot/start.elf" \
         "${FIRMWARE}/boot/start_x.elf" \
         "${FIRMWARE}/boot/start_cd.elf" \
         "${FIRMWARE}/boot/start_db.elf" \
         "${FIRMWARE}/boot/bootcode.bin"

# Magic thing to get debug output
sed -i -e "s/BOOT_UART=0/BOOT_UART=1/" bootcode.bin

# Create empty FAT partition
rm -f vfat.img
fallocate -l 31MiB vfat.img
mkfs.vfat vfat.img

# Copy boot files to FAT partition
mcopy -v -i vfat.img u-boot/u-boot.bin config.txt fixup*.dat start*.elf bootcode.bin ::

# Copy FAT partition to image
dd if=vfat.img of=tmp.img bs=1K seek=1K

truncate -s 32M tmp.img
gzip tmp.img
cp tmp.img.gz "${IMAGE}.bin.gz"