#
# Build and Setup RPi2 Kernel
#

# Load utility functions
. ./functions.sh

# Fetch and build latest raspberry kernel
if [ "$BUILD_KERNEL" = true ] ; then
  # Setup source directory
  mkdir -p "$R/usr/src"

  # Copy existing kernel sources into chroot directory
  if [ -n "$KERNELSRC_DIR" ] && [ -d "$KERNELSRC_DIR" ] ; then
    # Copy kernel sources
    cp -r "${KERNELSRC_DIR}" "${R}/usr/src"

    # Clean the kernel sources
    if [ "$KERNELSRC_CLEAN" = true ] && [ "$KERNELSRC_PREBUILT" = false ] ; then
      make -C "$R/usr/src/linux" ARCH="${KERNEL_ARCH}" CROSS_COMPILE="${CROSS_COMPILE}" mrproper
    fi
  else # KERNELSRC_DIR=""
    # Fetch current raspberrypi kernel sources
    git -C "$R/usr/src" clone --depth=1 https://github.com/raspberrypi/linux
  fi

  # Calculate optimal number of kernel building threads
  if [ "$KERNEL_THREADS" = "1" ] && [ -r /proc/cpuinfo ] ; then
    KERNEL_THREADS=$(grep -c processor /proc/cpuinfo)
  fi

  # Configure and build kernel
  if [ "$KERNELSRC_PREBUILT" = false ] ; then
    # Remove device, network and filesystem drivers from kernel configuration
    if [ "$KERNEL_REDUCE" = true ] ; then
      make -C "$R/usr/src/linux" ARCH="${KERNEL_ARCH}" CROSS_COMPILE="${CROSS_COMPILE}" "${KERNEL_DEFCONFIG}"
      sed -i\
      -e "s/\(^CONFIG_SND.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_SOUND.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_AC97.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_VIDEO_.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_MEDIA_TUNER.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_DVB.*\=\)[ym]/\1n/"\
      -e "s/\(^CONFIG_REISERFS.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_JFS.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_XFS.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_GFS2.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_OCFS2.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_BTRFS.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_HFS.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_JFFS2.*\=\)[ym]/\1n/"\
      -e "s/\(^CONFIG_UBIFS.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_SQUASHFS.*\=\)[ym]/\1n/"\
      -e "s/\(^CONFIG_W1.*\=\)[ym]/\1n/"\
      -e "s/\(^CONFIG_HAMRADIO.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_CAN.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_IRDA.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_BT_.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_WIMAX.*\=\)[ym]/\1n/"\
      -e "s/\(^CONFIG_6LOWPAN.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_IEEE802154.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_NFC.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_FB_TFT=.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_TOUCHSCREEN.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_USB_GSPCA_.*\=\).*/\1n/"\
      -e "s/\(^CONFIG_DRM.*\=\).*/\1n/"\
      "$R/usr/src/linux/.config"
    fi

    if [ "$KERNELSRC_CONFIG" = true ] ; then
      # Load default raspberry kernel configuration
      make -C "$R/usr/src/linux" ARCH="${KERNEL_ARCH}" CROSS_COMPILE="${CROSS_COMPILE}" "${KERNEL_DEFCONFIG}"

      # Start menu-driven kernel configuration (interactive)
      if [ "$KERNEL_MENUCONFIG" = true ] ; then
        make -C "$R/usr/src/linux" ARCH="${KERNEL_ARCH}" CROSS_COMPILE="${CROSS_COMPILE}" menuconfig
      fi
    fi

    # Cross compile kernel and modules
    make -C "$R/usr/src/linux" -j${KERNEL_THREADS} ARCH="${KERNEL_ARCH}" CROSS_COMPILE="${CROSS_COMPILE}" zImage modules dtbs
  fi

  # Check if kernel compilation was successful
  if [ ! -r "$R/usr/src/linux/arch/${KERNEL_ARCH}/boot/zImage" ] ; then
    echo "error: kernel compilation failed! (zImage not found)"
    cleanup
    exit 1
  fi

  # Install kernel modules
  if [ "$ENABLE_REDUCE" = true ] ; then
    make -C "$R/usr/src/linux" ARCH="${KERNEL_ARCH}" CROSS_COMPILE="${CROSS_COMPILE}" INSTALL_MOD_STRIP=1 INSTALL_MOD_PATH=../../.. modules_install
  else
    make -C "$R/usr/src/linux" ARCH="${KERNEL_ARCH}" CROSS_COMPILE="${CROSS_COMPILE}" INSTALL_MOD_PATH=../../.. modules_install

    # Install kernel firmware
    make -C "$R/usr/src/linux" ARCH="${KERNEL_ARCH}" CROSS_COMPILE="${CROSS_COMPILE}" INSTALL_FW_PATH=../../../lib firmware_install
  fi

  # Install kernel headers
  if [ "$KERNEL_HEADERS" = true ] && [ "$KERNEL_REDUCE" = false ] ; then
    make -C "$R/usr/src/linux" ARCH="${KERNEL_ARCH}" CROSS_COMPILE="${CROSS_COMPILE}" INSTALL_HDR_PATH=../.. headers_install
  fi

  # Prepare boot (firmware) directory
  mkdir "$R/boot/firmware/"

  # Get kernel release version
  KERNEL_VERSION=`cat "$R/usr/src/linux/include/config/kernel.release"`

  # Copy kernel configuration file to the boot directory
  install_readonly "$R/usr/src/linux/.config" "$R/boot/config-${KERNEL_VERSION}"

  # Copy dts and dtb device tree sources and binaries
  mkdir "$R/boot/firmware/overlays/"
  install_readonly "$R/usr/src/linux/arch/${KERNEL_ARCH}/boot/dts/"*.dtb "$R/boot/firmware/"
  install_readonly "$R/usr/src/linux/arch/${KERNEL_ARCH}/boot/dts/overlays/"*.dtb* "$R/boot/firmware/overlays/"
  install_readonly "$R/usr/src/linux/arch/${KERNEL_ARCH}/boot/dts/overlays/README" "$R/boot/firmware/overlays/README"

  # Copy zImage kernel to the boot directory
  install_readonly "$R/usr/src/linux/arch/${KERNEL_ARCH}/boot/zImage" "$R/boot/firmware/kernel7.img"

  # Remove kernel sources
  if [ "$KERNEL_REMOVESRC" = true ] ; then
    rm -fr "$R/usr/src/linux"
  fi

  # Install latest boot binaries from raspberry/firmware github
  wget -q -O "$R/boot/firmware/bootcode.bin" https://github.com/raspberrypi/firmware/raw/master/boot/bootcode.bin
  wget -q -O "$R/boot/firmware/fixup_cd.dat" https://github.com/raspberrypi/firmware/raw/master/boot/fixup_cd.dat
  wget -q -O "$R/boot/firmware/fixup.dat" https://github.com/raspberrypi/firmware/raw/master/boot/fixup.dat
  wget -q -O "$R/boot/firmware/fixup_x.dat" https://github.com/raspberrypi/firmware/raw/master/boot/fixup_x.dat
  wget -q -O "$R/boot/firmware/start_cd.elf" https://github.com/raspberrypi/firmware/raw/master/boot/start_cd.elf
  wget -q -O "$R/boot/firmware/start.elf" https://github.com/raspberrypi/firmware/raw/master/boot/start.elf
  wget -q -O "$R/boot/firmware/start_x.elf" https://github.com/raspberrypi/firmware/raw/master/boot/start_x.elf

else # BUILD_KERNEL=false
  # Kernel installation
  chroot_exec apt-get -qq -y --no-install-recommends install linux-image-"${COLLABORA_KERNEL}" raspberrypi-bootloader-nokernel

  # Install flash-kernel last so it doesn't try (and fail) to detect the platform in the chroot
  chroot_exec apt-get -qq -y install flash-kernel

  # Check if kernel installation was successful
  VMLINUZ="$(ls -1 $R/boot/vmlinuz-* | sort | tail -n 1)"
  if [ -z "$VMLINUZ" ] ; then
    echo "error: kernel installation failed! (/boot/vmlinuz-* not found)"
    cleanup
    exit 1
  fi
  # Copy vmlinuz kernel to the boot directory
  install_readonly "$VMLINUZ" "$R/boot/firmware/kernel7.img"
fi

# Setup firmware boot cmdline
if [ "$ENABLE_SPLITFS" = true ] ; then
  CMDLINE="dwc_otg.lpm_enable=0 root=/dev/sda1 rootfstype=ext4 rootflags=commit=100,data=writeback elevator=deadline rootwait net.ifnames=1 console=tty1 ${CMDLINE}"
else
  CMDLINE="dwc_otg.lpm_enable=0 root=/dev/mmcblk0p2 rootfstype=ext4 rootflags=commit=100,data=writeback elevator=deadline rootwait net.ifnames=1 console=tty1 ${CMDLINE}"
fi

# Add serial console support
if [ "$ENABLE_CONSOLE" = true ] ; then
  CMDLINE="${CMDLINE} console=ttyAMA0,115200 kgdboc=ttyAMA0,115200"
fi

# Remove IPv6 networking support
if [ "$ENABLE_IPV6" = false ] ; then
  CMDLINE="${CMDLINE} ipv6.disable=1"
fi

# Install firmware boot cmdline
echo "${CMDLINE}" > "$R/boot/firmware/cmdline.txt"

# Add encrypted root partition to cmdline.txt
if [ "$ENABLE_CRYPTFS" = true ] ; then
    sed -i "s/mmcblk0p2/mapper\/${CRYPTFS_MAPPING} cryptdevice=\/dev\/mmcblk0p2:${CRYPTFS_MAPPING}/" "$R/boot/firmware/cmdline.txt"
fi

# Install firmware config
install_readonly files/boot/config.txt "$R/boot/firmware/config.txt"

# Setup minimal GPU memory allocation size: 16MB (no X)
if [ "$ENABLE_MINGPU" = true ] ; then
  echo "gpu_mem=16" >> "$R/boot/firmware/config.txt"
fi

# Setup boot with initramfs
if [ "$ENABLE_INITRAMFS" = true ] ; then
  echo "initramfs initramfs-${KERNEL_VERSION} followkernel" >> "$R/boot/firmware/config.txt"
fi

# Create firmware configuration and cmdline symlinks
ln -sf firmware/config.txt "$R/boot/config.txt"
ln -sf firmware/cmdline.txt "$R/boot/cmdline.txt"

# Install and setup kernel modules to load at boot
mkdir -p "$R/lib/modules-load.d/"
install_readonly files/modules/rpi2.conf "$R/lib/modules-load.d/rpi2.conf"

# Load hardware random module at boot
if [ "$ENABLE_HWRANDOM" = true ] ; then
  sed -i "s/^# bcm2708_rng/bcm2708_rng/" "$R/lib/modules-load.d/rpi2.conf"
fi

# Load sound module at boot
if [ "$ENABLE_SOUND" = true ] ; then
  sed -i "s/^# snd_bcm2835/snd_bcm2835/" "$R/lib/modules-load.d/rpi2.conf"
fi

# Install kernel modules blacklist
mkdir -p "$R/etc/modprobe.d/"
install_readonly files/modules/raspi-blacklist.conf "$R/etc/modprobe.d/raspi-blacklist.conf"

# Install and setup fstab
install_readonly files/mount/fstab "$R/etc/fstab"

# Add usb/sda disk root partition to fstab
if [ "$ENABLE_SPLITFS" = true ] ; then
  sed -i "s/mmcblk0p2/sda1/" "$R/etc/fstab"
fi

# Add encrypted root partition to fstab and crypttab
if [ "$ENABLE_CRYPTFS" = true ] ; then
  # Replace fstab root partition with encrypted partition mapping
  sed -i "s/mmcblk0p2/mapper\/${CRYPTFS_MAPPING}/" "$R/etc/fstab"

  # Add encrypted partition to crypttab and fstab
  install_readonly files/mount/crypttab "$R/etc/crypttab"
  echo "${CRYPTFS_MAPPING} /dev/mmcblk0p2 none luks" >> "$R/etc/crypttab"
fi

# Generate initramfs file
if [ "$ENABLE_INITRAMFS" = true ] ; then
  if [ "$ENABLE_CRYPTFS" = true ] ; then
    # Dummy mapping required by mkinitramfs
    echo "0 1 crypt $(echo ${CRYPTFS_CIPHER} | cut -d ':' -f 1) ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff 0 7:0 4096" | chroot_exec dmsetup create "${CRYPTFS_MAPPING}"

    # Generate initramfs with encrypted root partition support
    chroot_exec mkinitramfs -o "/boot/firmware/initramfs-${KERNEL_VERSION}" "${KERNEL_VERSION}"

    # Remove dummy mapping
    chroot_exec cryptsetup close "${CRYPTFS_MAPPING}"
  else
    # Generate initramfs without encrypted root partition support
    chroot_exec mkinitramfs -o "/boot/firmware/initramfs-${KERNEL_VERSION}" "${KERNEL_VERSION}"
  fi
fi

# Install sysctl.d configuration files
install_readonly files/sysctl.d/81-rpi-vm.conf "$R/etc/sysctl.d/81-rpi-vm.conf"