#!/bin/bash

INST_DRIVER=0

PRJ_PATH=`pwd`

IMG_PATH=${PRJ_PATH}/../images/bin
  
BOARD=imx6ull
 
CROSS_TOOL=/opt/buildroot/cortexA7/bin/arm-linux-

# linux kernel tarball path and branch
TAR_PATH=${PRJ_PATH}/../tarball
BSP_BRANCH=lf-5.10.52-2.1.0

BOOT=emmc

LINUX_SRC=linux-imx

PATCH_FILE=${PRJ_PATH}/patch/${LINUX_SRC}-${BOARD}.patch

CONF_FILE=.cfg-${BOARD}

JOBS=`cat /proc/cpuinfo | grep processor | wc -l`

set -u
set -e

STAGE=0

function msg_banner()
{ 
	STAGE=`expr $STAGE + 1`
	
    echo ""
    echo "+---------------------------------------------+" 
    printf " Stage $STAGE: $1\n" 
    echo "+---------------------------------------------+"
    echo ""
}

function do_fetch()
{
    msg_banner "Fetch ${LINUX_SRC} source code"
    if [ -d ${LINUX_SRC} ] ; then 
        printf "\n\n -- ${LINUX_SRC} fetched already -- \n\n"
        return 0;
    fi

    printf "\n -- decompress ${LINUX_SRC}-${BSP_BRANCH}.tar.xz now ... -- \n\n"
    tar -xJf ${TAR_PATH}/${LINUX_SRC}-${BSP_BRANCH}.tar.xz
}

function do_patch()
{
    msg_banner "Patch for ${LINUX_SRC} source code"

    cd ${LINUX_SRC}

    if [ ! -s $CONF_FILE -a  -s $PATCH_FILE ] ; then
        patch -p1 < $PATCH_FILE
    fi

    printf "\n\nModify cross compiler in Makefile: $CROSS_TOOL\n\n"
    sed -i -e "s|^CROSS_COMPILE=.*|CROSS_COMPILE=${CROSS_TOOL}|g" Makefile

    cd ${PRJ_PATH}
}
  
function do_build()
{
    msg_banner "Build for ${LINUX_SRC} source code"

    cd ${LINUX_SRC}

    if [ ! -f .config ] ; then 
        cp $CONF_FILE .config
    fi

    make -j ${JOBS}


    cd ${PRJ_PATH}
}


function do_install()
{
    msg_banner "Install linux kernel image"

    cd ${LINUX_SRC}

    mkdir -p ${IMG_PATH}

    cp arch/arm/boot/zImage ${IMG_PATH}
    cp arch/arm/boot/dts/imx6ul-14x14-evk-emmc.dtb ${IMG_PATH}/${BOARD}-${BOOT}.dtb

    cp arch/arm/boot/zImage /tftp
    cp arch/arm/boot/dts/imx6ul-14x14-evk-emmc.dtb /tftp/${BOARD}-${BOOT}.dtb

    if [ $INST_DRIVER != 0 ]  ;then
        make modules_install INSTALL_MOD_PATH=${PRJ_PATH}/../rootfs INSTALL_MOD_STRIP=1
    fi

    cd ${PRJ_PATH}
}

function do_clean()
{
    msg_banner "Clean ${LINUX_SRC} source code"

    cd ${LINUX_SRC}

    cp .config $CONF_FILE
    make distclean

    cd ${PRJ_PATH}
}

function gen_patch()
{ 
    do_clean

    mv ${LINUX_SRC} ${LINUX_SRC}-${BOARD} 

    do_fetch

    msg_banner "Generate ${LINUX_SRC} patch file"

    set +e
    diff -Nuar ${LINUX_SRC} ${LINUX_SRC}-${BOARD} > ${LINUX_SRC}-${BOARD}.patch

    rm -rf ${LINUX_SRC}
    mv ${LINUX_SRC}-${BOARD} ${LINUX_SRC}
}

if [[ $# == 1 ]] && [[ $1 == "patch" ]] ; then
    gen_patch
    exit 0;
fi

do_fetch

do_patch

do_build

do_install