TinaLinux on Nezha

 Generally I am happy with Debian as the OS on a microprocessor.  I am most familiar with it since it is installed on RPi and I use it regularly.

Allwinner have developed TinaLinux for thei embedded systems.  It is based on OpenWrt which was initially targetted as a Linux implementation for routers.  TinaLinux compressed images are upto 100MB in size compared with about 1GB for a Debian image including GUI.

Some Sipeed D1-Nezha boards apparenly had TinaLinux in flash memory when they were delivered but mine didn't and I wanted to find out more.  There wasn't a Tina image available for the Nezha, although there is one for the LicheeRV, and I successfully booted the LicheeRV Tina SD card on Nezha.

Allwinner provide an SDK for creating Tina builds - you can specify in great detail which Linux features and comands you want to include and use the Linux "make" command to compile the software and build the image.  Images can be burned to SD card or copied to Nand flash memory.  When you boot from an image you can test that the features and commands work as expected.

Setup SDK

There are various pre-requisites and requirements for the environment hosting Tina SDK.  In particular, you are advised to to use an old (v14 from 2014) version of Ubuntu.  Luckily a Virtualbox VM is available from Allwinner which has been setup with appropriate software.  I downloaded it (1.6GB) and started it up in the VirtualBox environment.  The VM supports shared folders and has a network connection so I am easily able to transfer files to / from the VM and download software from the internet.

The next step is to download the Tina SDK from Allwinner.  A user registration is required together with a public key from the recipient machine to obtain access to the download.  I created keys with  ssh-keygen on my Ubuntu VM and uploaded the public key to the Allwinner site.  Following their instructions I used the repo command to download the SDK from github.  The download took well over two hours and resulted in 11GB of software in the tina-d1-open folder.

Build an Image

Rather than doing any configuration I decided to build an image based on the configuration provided.  It took some time to compile everything, but after 8 hours I saw a message saying the build was successful.  I was then able to pack the image, copy it to Windows and use PhoenixCard to burn it to SD card.  Amazingly the SD card booted into linux (the first part of the boot is shown below) and I was able to sign on to TinaLinux on the serial console and have a look around.

Test the system

The first problem I had was that the filesystem has no spare space, and in fact it is read-only - which is appropriate for a nand flash load but doesnt help me.

It took me a while to work out where the system partition table is defined within the Tina SDK but once I had made it somewhat bigger and rebuilt the system I had some space available.  Of course the make utility only recompiles changes and the rebuild was complete in 10 minutes.  I couldn't find a place in the SDK to make the root filesystem read-write so I remounted the disk at first startup.

Now that we have a system we can configure I tried to get a network.  The ifconfig and udhcpc utility will start up ethernet but wifi would't work for me.  With ethernet working I rebuilt the system to include sshd-server and after booting I was able to start sshd and ssh into the system from a remote terminal.

For the moment I don't want to do too much configuration.  I contented myself with adding a small web server (uhttpd) and fdisk providing the ability to modify partitions.

Each time the system is rebuilt any tailoring is lost.  Luckily my Nezha has a USB stick plugged in and it is useable from Tina so I created a script on the stick which I can run on boot.  This mounts rootfs read-write, starts sshd and permits root to have ssh access locally.

In conclusion I am very pleased that I have been able to build a TinaLinux system and test it on the Nezha.