#!/bin/sh

# kernel_raspi.SlackBuild
# Build the kernel for Raspberry Pi
#
# 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.

#------------------------------------------------------------------------------
#
# Before running this SlackBuild you must get a tarball of the kernel
# source from the 3.6.y branch of the raspberrypi's repository: a script
# is here to help that
#
#  sh get_kernel_source.sh
#
#------------------------------------------------------------------------------

FLAVOUR=raspi
PRGNAM=kernel_$FLAVOUR

# If not set in the environment, MYVER will be set from today's date
MYVER=${VERSION:-$(date '+%Y%m%d')}
BUILD=${BUILD:-1}
TAG=${TAG:-_dbs}

KNLARCH=${ARCH:-arm}
unset ARCH

CONFIG=${CONFIG:-config-$FLAVOUR}

CWD=$(pwd)
TMP=${TMP:-/tmp}
PKG=$TMP/package-$PRGNAM
OUTPUT=${OUTPUT:-/tmp}

set -e

rm -rf $PKG
mkdir -p $PKG

GITREV=${GITREV:-$(echo raspberrypi-linux-*.tar.gz | sed -e "s|raspberrypi-linux-||" -e "s|\.tar\.gz||")}

rm -fr linux
echo "Uncompressing the kernel silently to avoid spamming the console too much."
echo "It can take a while..."
echo "tar xf $CWD/raspberrypi-linux-$GITREV.tar.gz"
tar xf $CWD/raspberrypi-linux-$GITREV.tar.gz
mv raspberrypi-linux-$GITREV linux
# Uncompress also aufs3 sources
tar xf $CWD/aufs3-3.6.tar.gz

cd $CWD/linux

if [ -d $CWD/patches/ ]; then
  git checkout -f
  for pf in $CWD/patches/*; do
    patch --verbose -p1 <$pf
  done
fi

cat $CWD/$CONFIG > .config

# Add the bfq patches
patch -p1 < $CWD/0001-block-cgroups-kconfig-build-bits-for-BFQ-v6r1-3.6.patch
patch -p1 < $CWD/0002-block-introduce-the-BFQ-v6r1-I-O-sched-for-3.6.patch
patch -p1 < $CWD/0003-block-bfq-add-Early-Queue-Merge-EQM-to-BFQ-v6r1-for-3.6.0.patch

# Add aufs3 stuff
cp -a $CWD/aufs3-3.6/Documentation/ABI/testing/* Documentation/ABI/testing/
cp -a $CWD/aufs3-3.6/Documentation/filesystems/aufs Documentation/filesystems/
cp -a $CWD/aufs3-3.6/fs/aufs fs/
cp -a $CWD/aufs3-3.6/include/linux/aufs_type.h include/linux/
patch -p1 < $CWD/aufs3-3.6/aufs3-kbuild.patch
patch -p1 < $CWD/aufs3-3.6/aufs3-base.patch
patch -p1 < $CWD/aufs3-3.6/aufs3-proc_map.patch

make silentoldconfig LOCALVERSION="-$MYVER"

head -4 Makefile | sed 's/ *= */=/' > $TMP/versionvars
. $TMP/versionvars
rm $TMP/versionvars
KNLVER="${VERSION}.${PATCHLEVEL}.${SUBLEVEL}${EXTRAVERSION}-${MYVER}"
PKGVER=$(echo "$KNLVER" | tr - _)

make zImage $NUMJOBS LOCALVERSION="-$MYVER"

mkdir -p $PKG/boot

cp arch/arm/boot/zImage $PKG/boot/kernel.img
cp System.map $PKG/boot/System.map

# Put this in /usr/doc to avoid confusion with Pi-specific /boot/config.txt
mkdir -p $PKG/usr/doc/$PRGNAM-$PKGVER
cat .config > $PKG/usr/doc/$PRGNAM-$PKGVER/config

# Create /boot/cmdline.txt copied from kernel config
# Install as .new even though it's not in /etc
# Root device will be filled in by doinst.sh
grep 'CONFIG_CMDLINE=' .config | \
  sed -e 's/CONFIG_CMDLINE="//' -e 's/"$//' -e 's:root=/dev/mmcblk0p[0-7]:root=@ROOTDEV@:' \
  > $PKG/boot/cmdline.txt.new

mkdir -p $PKG/install
cat $CWD/slack-desc > $PKG/install/slack-desc
cat $CWD/doinst.sh > $PKG/install/doinst.sh

# Add version stamp into /boot and /usr/doc
echo "Package: $PRGNAM-$PKGVER-$KNLARCH-$BUILD$TAG" \
  >  $PKG/boot/version-$PRGNAM.txt
echo "Build date: $(date -u '+%F %T')" \
  >> $PKG/boot/version-$PRGNAM.txt
echo "Git revision: $GITREV" \
  >> $PKG/boot/version-$PRGNAM.txt
cp \
  $PKG/boot/version-$PRGNAM.txt \
  $PKG/usr/doc/$PRGNAM-$PKGVER/version.txt

cd $PKG
/sbin/makepkg -l y -c n $OUTPUT/$PRGNAM-$PKGVER-$KNLARCH-$BUILD$TAG.${PKGTYPE:-tgz}

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

# Prepare and install the modules.  The kernel-modules SlackBuild traditionally
# just picks them up from the running system.
cd $CWD/linux
make modules $NUMJOBS LOCALVERSION="-$MYVER"
make modules_install

# Link the source for the modules & source SlackBuilds
rm -rf /usr/src/linux; ln -s $CWD/linux /usr/src/linux
( cd /lib/modules/$KNLVER
  rm build;  ln -s /usr/src/linux build
  rm source; ln -s /usr/src/linux source
)

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

# Finished.
exit 0