build_kernel

#!/bin/bash 

# RMIT USAP Assignment 2 build_kernel
# Author : Aldo Irvine
# Email : s3692192@student.rmit.edu.au
# Pi Version : 4


# Command list :
ECHO=/bin/echo
GIT=/usr/bin/git
LS=/bin/ls
CP=/bin/cp
MAKE=/usr/bin/make
TAR=/bin/tar
RM=/bin/rm
MONITOR=./performance_monitoring



# Install pre-requisites tools 
$ECHO "0. Installing pre-requisite package to compile"
$ECHO
sudo apt install raspberrypi-kernel-headers build-essential bc git wget bison flex libssl-dev make


# 1. Checkout private repo (https://github.com/AldoIrvine111/usapA3)

# Use if statement to check if repo is not existed, cloned else pull to update latest changes made in repo.


$ECHO
$ECHO "1. Checkout private repo"

if [ -d usapA3 ]
then
	cd usapA3 || exit
	# Pull any changes made
	$ECHO "Directory usapA3 exist, pulling latest master branch"
	$GIT pull
	cd ..	
else
	$ECHO "Directory usapA3 does not exist, cloning repo using SSH"
	$GIT clone git@github.com:AldoIrvine111/usapA3.git
	$LS -a 
	$ECHO "Complete cloning repo (usapA3)"
fi



# 2. Checkout raspberry pi kernel repository

# Use if statement to check if repo is not existed, cloned else pull to update latest changes made in repo.


$ECHO 
$ECHO "2. Checkout raspbbery pi kernel repository"

if [ -d linux ]
then
	cd linux || exit
	# Pull any changes made
	$ECHO "Directory linux exist" 
	cd ..
else
	$ECHO "Directory linux does not exist, cloning repo"
	$GIT clone --depth=1 https://github.com/raspberrypi/linux 
	$ECHO "Complete cloning repo (linux)"
fi

$ECHO 
$LS -a 
$ECHO



# 3. Copy your ".config" file into the right place

# Copy .config file from usapA3 to linux 

cd usapA3 || exit

if [ -e .config ] 
then 
	$ECHO "3. Copying .config to ../linux"
	$CP .config ../linux
else
	$ECHO ".config file does not exist"
	exit 1
fi
$ECHO


# 4. Build kernel

# Initiate performance_monitoring script
$ECHO "Starting performance script"
cd .. || exit
$MONITOR &

# Capture the ID of performance_monitoring script
SID=$(ps -A | awk '/performance_mon/{print $1}')
$ECHO "$SID"
sleep 5
cd linux/ || exit
# Compile kernel
# Set kernel based on Pi version 4
$ECHO "4. Compiling kernel"
KERNEL=kernel7l
$ECHO "Using $KERNEL for Pi4"
$MAKE -j4 zImage modules dtbs
$ECHO "Image is ready"
$ECHO
# Send USR1 signal to stop performance_monitoring through the ID
kill -USR1 "$SID"
cd .. || exit


# 5. Make backup for /boot before pasting new kernel

IMAGE_NAME=raspberry-pi-2020-backup.tar.gz
if [ -e "$IMAGE_NAME" ] 
then
	$ECHO "Deleting old backup and make new backup"
	$RM "$IMAGE_NAME"
	$TAR -zcvf "$IMAGE_NAME" /boot
else
	$ECHO "Backup"
	$TAR -zcvf "$IMAGE_NAME" /boot
fi
$ECHO
$ECHO "Backup complete"

# 6. Copy new kernel to /boot
cd linux/ || exit
sudo $MAKE modules_install
sudo $CP arch/arm/boot/dts/*.dtb /boot/
sudo $CP arch/arm/boot/dts/overlays/*.dtb* /boot/overlays/
sudo $CP arch/arm/boot/dts/overlays/README /boot/overlays/
sudo $CP arch/arm/boot/zImage /boot/$KERNEL.img