C-SKY – The Chinese CPU Architecture in Linux Mainline!


C-SKY is a CPU architecture that is designed to be used in DVB set-top TV boxes. In Late 2018 Linux was ported to the C-SKY Architecture and accepted into Mainline. This is likely the last CPU Architecture to be added to mainline Linux.

C-Sky Architecture

C-SKY was recently acquired by Alibaba and the CPU is likely to be used in IOT devices for the Alibaba Cloud. A such device is currently available but there is little to no information on this.

IOT Dev board that is undocumented and not available outside of China.

C-SKY Dev Board and Linux

My c-sky Dev board booted from USB with Ethernet provided from a cheap USB Adapter.

Back in November of 2018 I purchased a C-SKY dev board from Aliexpress for around £4. This board is powered by the C-Sky CK610 a ~500Mhz single core CPU and 64MB of DDR2 RAM. Linux Support was practically non existent back then so the Dev board was forgotten about until I stumbled across it a few weeks back. Linux support is better but still not suitable for a novice, the image provided by C-SKY contains nothing but a base install of busybox with no applications or binaries.

I built linux using build root found here with several packages including:
Ethernet drivers

CPU Architecture as detected by Linux

This took around 6 hours to compile on a 2017 i7 Macbook Pro.

Performance is as expected although I’m not going to run any benchmarks, its a single core SOC with 64MB RAM so performance is naturally poor although it is capable of hosting a small website – surprisingly well actually!

For anyone that is uninterested in using buildroot my image can be downloaded here

There is also a limited number of GPIO pins, 5 Input buttons and 4 GPIO LED’s.

There is a handy script in /python-gpio to test this:

Input shown from pressing the buttons on the SBC.

bash test-out.sh will flash the output LED’s one at a time.

LED’s Flashing using test-out.sh
htop showing the usage running nginx & php-fpm

Overall the Dev board is a great way to start development for the C-SKY Architecture and it likely only exists to gain a following and to get the community involved in maturing the Linux Support.

I still haven’t decided what to to with this although I am trying to gather some support do create a Debian port for C-SKY. I’m interested to see where this Architecture will go and wether or not a more capable SOC will be released but for a first attempt on a brand new Architecture its really not a bad effort!

The Dev-Board can be purchased here.

This has been shared a lot and I can’t keep up with the comments! Please let me know below if you have any questions.

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