#!/bin/sh

# installer.SlackBuild
# Build a Raspberry Pi installer image
#
# Copyright 2012 David Spencer, Baildon, West Yorkshire, U.K.
# All rights reserved.
#
# Redistribution and use of this script, with or without modification, is
# permitted provided that the following conditions are met:
#
# 1. Redistributions of this script must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
#
#  THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR IMPLIED
#  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
#  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
#  EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
#  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
#  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
#  OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
#  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
#  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
#  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#------------------------------------------------------------------------------
#
# To run this script you will need:
#   * initrd-versatile.img in this directory, possibly as a symlink to your
#     armedslack-current tree (it's in armedslack-current/isolinux)
#   * A recently built kernel tree with 'Image' and modules in
#     '../kernel_raspi/linux'
#   * The firmware folder in '../raspi-boot/firmware'
#   * 'Extra' packages already built in $OUTPUT
#
#------------------------------------------------------------------------------

TMP=${TMP:-/tmp}
OUTPUT=${OUTPUT:-/tmp}

MYTMP=$TMP/installer
IMAGE=raspi-slack-installer_$(date '+%d%b%y').img

CWD=$(pwd)

rm -rf $MYTMP
mkdir -p $MYTMP

set -e

#------------------------------------------------------------------------------
# (0) Extract the installer tree from the upstream initrd

rm -rf $MYTMP/initrd-tree
mkdir -p $MYTMP/initrd-tree
cd $MYTMP/initrd-tree
zcat $CWD/initrd-versatile.img | cpio -iv

#------------------------------------------------------------------------------
# (1) Add raspi device nodes (maybe not needed -- to be checked)
#
# cd $MYTMP/initrd-tree/
# tar xvf $CWD/../raspi-devs/_devs.tar.xz
#
#------------------------------------------------------------------------------
# (2) Add README and raspi-extra to the installer tree

cat $CWD/README.installer > $MYTMP/initrd-tree/README

mkdir -p $MYTMP/initrd-tree/raspi-extra
for pkgbase in \
  raspi-boot \
  raspi-hacks \
  kernel_raspi \
  kernel-modules-raspi
do
  pkg=$(ls -t $OUTPUT/$pkgbase-*.t?z | head -1)
  cp -a -v \
    $pkg \
    $MYTMP/initrd-tree/raspi-extra/
done

#------------------------------------------------------------------------------
# (3) Add kernel modules to the installer tree

# Remove the versatile modules
# (it might be helpful to qemu users to keep them, but they're just too big)
rm -rf $MYTMP/initrd-tree/lib/modules/*

cd $CWD/../kernel_raspi/linux
make modules_install INSTALL_MOD_PATH=$MYTMP/initrd-tree

#------------------------------------------------------------------------------
# (4) Roll the initrd.  We name it 'install.gz' so it's recognisable and
# can be removed after installation.

cd $MYTMP/initrd-tree
find . | cpio -o -v -H newc | gzip -9c > $MYTMP/install.gz

#------------------------------------------------------------------------------
# (5) Make an empty image and format it

rm -f $MYTMP/$IMAGE
echo "Making $MYTMP/$IMAGE"

# Let's work in 512B sectors.
# 128 "heads" and 32 "sectors" => 2MiB "cylinders",
# That's 4096 sectors per "cylinder".
# 4 "cylinders" = 8MiB erase block boundary (or 2*4MiB boundaries).
# So keep partition boundaries at 4-cyl multiples for best results.
# That's 16384 sectors per erase block.
# 944 "cylinders" = 1979711488B, which is < 2MB, so fits on a "2Mb" card.
dd if=/dev/zero of=$MYTMP/$IMAGE bs=512 count=$(( 128 * 32 * 944 ))

# Drop in the prepared MBR.
# Partition 1 start       1 end  180223 type 0c
# Partition 2 start  180224 end 1032191 type 82
# Partition 3 start 1032192 end 3866623 type 83
dd if=$CWD/mbr of=$MYTMP/$IMAGE bs=512 count=1 conv=notrunc

LOOPDEV=$(losetup -f --show $MYTMP/$IMAGE)
mdadm --build --force raspimg --level linear --raid-devices 1 $LOOPDEV
# It takes a few secs to ready /dev/md/* apparently
sleep 5

mkdosfs -I /dev/md/raspimg1
mkswap /dev/md/raspimg2
mkfs -t ext4 -O ^has_journal -E stride=2,stripe-width=1024 -b 4096 /dev/md/raspimg3

# Save the empty SD card image as a useful by-product.
# (Very time consuming, so only do this if needed.)
EMPTY=raspi-empty-sdcard.img
if [ ! -f $OUTPUT/$EMPTY.gz ]; then
  echo "Compressing image to $OUTPUT/$EMPTY.gz"
  gzip -c $MYTMP/$IMAGE     > $OUTPUT/$EMPTY.gz
  sha1sum $OUTPUT/$EMPTY.gz > $OUTPUT/$EMPTY.gz.sha1
fi

#------------------------------------------------------------------------------
# (6) Copy everything onto image partition 1

mkdir -p $MYTMP/mnt
mount -t vfat /dev/md/raspimg1 $MYTMP/mnt

# Get the boot firmware and default config
cd $CWD/../raspi-boot/firmware
cp -v \
  boot/bootcode.bin \
  boot/LICENCE.broadcom \
  $MYTMP/mnt
cp -v \
  boot/start*.elf \
  boot/fixup*.dat \
  $MYTMP/mnt/
# Use 16 Mb of the memory for the graphics,
# so we have the rest for the installer
sed "s|@GPUMEM@|16|" $CWD/../raspi-boot/config.txt > $MYTMP/mnt/config.txt

# Kernel
cp -v \
  $CWD/../kernel_raspi/linux/arch/arm/boot/zImage \
  $MYTMP/mnt/kernel.img
# Pass a simplified command line
echo "dwc_otg.lpm_enable=0 console=tty1" > $MYTMP/mnt/cmdline.txt

# Get install.gz
cp -v \
  $MYTMP/install.gz \
  $MYTMP/mnt/

# Add initrd stuff for install.gz to /boot/config.txt and /boot/cmdline.txt
LOADADDR="0xa00000"
SIZE="0x$(printf '%x' $(stat --format='%s' $MYTMP/mnt/install.gz))"
echo "initramfs install.gz $LOADADDR" >> $MYTMP/mnt/config.txt
sed -i -e "s/\$/ initrd=$LOADADDR,$SIZE/" $MYTMP/mnt/cmdline.txt

# Assemble the README
cat $CWD/README.installer                   > $MYTMP/mnt/README
echo ""                                    >> $MYTMP/mnt/README
echo ""                                    >> $MYTMP/mnt/README
cat $MYTMP/initrd-tree/.installer-version  >> $MYTMP/mnt/README
echo "Raspberry Pi:"                       >> $MYTMP/mnt/README
echo "-------------"                       >> $MYTMP/mnt/README
KREV=$(echo $CWD/../kernel_raspi/raspberrypi-linux-*.tar.gz | sed -e "s|.*raspberrypi-linux-||" -e "s|\.tar\.gz||")
echo "Kernel git rev.......: $KREV"        >> $MYTMP/mnt/README
BREV=$(echo $CWD/../raspi-boot/raspberrypi-firmware-*.tar.gz | sed -e "s|.*raspberrypi-firmware-||" -e "s|\.tar\.gz||")
echo "Boot fw git rev......: $BREV"        >> $MYTMP/mnt/README
echo "Build host...........: $(uname -a)"  >> $MYTMP/mnt/README
echo "Build date...........: $(date)"      >> $MYTMP/mnt/README

#------------------------------------------------------------------------------
# (7) Compress and do a checksum

umount -v $MYTMP/mnt
mdadm --stop /dev/md/raspimg
losetup -d $LOOPDEV

echo "Compressing image to $OUTPUT/$IMAGE.gz"
gzip -c $MYTMP/$IMAGE     > $OUTPUT/$IMAGE.gz
sha1sum $OUTPUT/$IMAGE.gz > $OUTPUT/$IMAGE.gz.sha1

rm $MYTMP/$IMAGE

#------------------------------------------------------------------------------

exit 0