Re: Add network device to L4Linux

Hello everyone,

Yesterday with Yang we found why adding the device tree caused the
L4linux boot to fail on Cubietruck with "failed to get physical address
for 2000000". I am sharing this here for future references in case
anyone needs it.

Yang was using the sun7i-a20-cubietruck.dts [1] device tree which is
normally supposed to be used by Linux running on bare-metal arm. In
L4Linux's case it's running on top of L4 which controls what L4linux can
see. As a result of using sun7i-a20-cubietruck.dts it tries to map a
physical address which it's not allowed to.

Using what Matthias described in [2], one needs to create a new device
tree based on the simple.dts inside l4linux-source/arch/l4/boot/dts/ and
add the information about the ethernet device and its dependencies
there. Also don't forget to write the io configuration for those devices.

Another mail from Matthias which serves as a really nice explanation of
the process is [3].

Thank you,
Manolis

[1]
http://elixir.free-electrons.com/u-boot/latest/source/arch/arm/dts/sun7i-a20-cubietruck.dts
[2] https://os.inf.tu-dresden.de/pipermail/l4-hackers/2016/007747.html
[3] https://os.inf.tu-dresden.de/pipermail/l4-hackers/2017/008069.html