Complete fossbot project package.

How to

Use git submodules

https://git-scm.com/book/en/v2/Git-Tools-Submodules

Get cross-compiler

Download latest Linaro GCC

Example:

LINARO=gcc-linaro-7.5.0-2019.12-x86_64_arm-linux-gnueabihf
wget https://releases.linaro.org/components/toolchain/binaries/latest-7/arm-linux-gnueabihf/"$LINARO".tar.xz
tar -xf "$LINARO".tar.xz

export CROSS_COMPILE=$PWD/"$LINARO"/bin/arm-linux-gnueabihf-

Get rootfs

Get any debian-based built for arm half-precision target.

For example, here

Build kernel

Patch kernel with this or use pre-patched kernel from here.

Create default configuration, then run make ARCH=arm menuconfig

In General setup uncheck Automatically append version information to the version string for convenience. In Enable the block layer check Support for large (2TB+) block devices and files. If you want to use bluetooth, check all bluetooth-related options (you will probably need to check HID drivers and enable User-space I/O driver support for HID subsystem.

Example .config can be found in /kernel

Run make ARCH=arm LOCALVERSION= zImage to build kernel.

Build kernel modules

This will produce kernel object file(s) that can be insmoded:

cd kmod
# Change KDIR path to match your kernel root directory in Makefile, then run
make

Build disk image

# Create file
DISKFILE=disk.img
fallocate -l 4G $DISKFILE
DEV=$(losetup -f --show $DISKFILE)

# Partition
fdisk $DEV
# in fdisk:
	n
	p
	3
	<Return>
	+1M
	t
	a2
	n
	p
	2
	<Return>
	+256M
	n
	p
	1
	<Return>
	<Return>
	t
	1
	b
	w
	
# partition table should look like this:
# Device       Boot  Start     End Sectors  # Size Id Type
# /dev/loop0p1      528384 8388607 7860224  # 3.8G  b W95 FAT32
# /dev/loop0p2        4096  528383  524288  # 256M 83 Linux
# /dev/loop0p3        2048    4095    2048    # 1M a2 unknown

partprobe $DEV

# Format
mkfs -t vfat "$DEV"p1
mkfs.ext4 "$DEV"p2

# Copy preloader
PRELOADER=preloader-mkpimage.bin
cp $PRELOADER "$DEV"p3

# Copy fpga rom, device treem kernel and boot stuff
mkdir boot
mount "$DEV"p1 boot
UBOOT_IMG=u-boot.img
UBOOT_SCR=u-boot.scr
DEV_TREE=soc_system.dtb
FPGA_ROM=soc_system.rbf
KERNEL=zImage
cp UBOOT_IMG UBOOT_SCR DEV_TREE FPGA_ROM KERNEL boot && sync
unmount boot

# Copy rootfs
mkdir rootfs
mount "$DEV"p2 rootfs
ROOTFS=debian.tar
tar -xf ROOTFS -C rootfs && sync

# At this point you can copy anything you need, for example scripts and built kernel modules

unmount rootfs

losetup -d $DEV

Configure system

You may want to first configure SSH and network for convenience.

Assuming Debian 10:

Copy or clone contents of this repo, for example to /root.

In /etc/systemd/system/:

In dbus-org.bluez.service add --compat to ExecStart arguments.

Add reset-usb.service with the following content and modified paths if needed:

[Unit]
Description=Reset USB service
Before=bluetooth.service

[Service]
ExecStart=/root/scripts/reset-usb.sh

[Install]
WantedBy=multi-user.target

Add rfcomm-server.service with the following content and modified paths if needed:

[Unit]
Description=RFCOMM Server Setup
After=bluetooth.service
Requires=bluetooth.service

[Service]
ExecStart=/root/scripts/rfcomm-server.sh
Restart=on-failure

[Install]
WantedBy=multi-user.target

Execute

systemctl enable reset-usb.service
systemctl enable rfcomm-server.service

Kernel modules

You may want to load kernel modules on boot. A simple way to do this is to create a file yourmodule.conf in /lib/modprobe.d with the following content: install yourmodule insmod /path/to/yourmodule.ko.