How to run Genode with L4Linux having only one RS232 port

[Norman Feske]

Hello Evgeny,

> I am trying Genode on some different ARM platforms such as:
> a) Nvidia Tegra 250 (Development Kit board)
> b) Beagle board (www.beagleboard.org)
> I have no problem to build and run Genode having FOC kernel support for 
> these boards (working via UART terminal without graphics) But to run L4 
> Linux the Terminal session is needed, and that session can only be 
> provided via user (not kernel) UART. But there is no possibility to use 
> another UART, other than we have for kernel standard input/output (board 
> b without extentions has only one RS232) So, is there any possibility to 
> use only one terminal connection for kernel and l4linux simultaniously 
> (the same console for input/output)?  For example, a stub uart driver 
> that redirects uart IO&interrupts to standard IO?

currently there is no way to multiplex multiple terminal sessions over
one UART. For cases like this, you might instead opt for one of the
alternative terminal implementations, namely the framebuffer-based
terminal or the TCP terminal.

The framebuffer-based terminal located at 'gems/src/server/terminal'
provides the terminal service via an interactive on-screen console
using, in turn, the framebuffer and input services. It can be used
either directly with framebuffer and input drivers or by connecting it
to to a virtual framebuffer (e.g., liquid_fb or nit_fb, both in the 'os'
repository) running on the nitpicker GUI server.

For you, the TCP terminal may even be more handy. It provides the
terminal session interface over one TCP connection per terminal session
using the lwIP TCP/IP stack. You can find the code at
'gems/src/server/tcp_terminal'. There is also a simple run script for
trying it out quickly, see 'gems/run/tcp_terminal.run'. Of course, you
will need a NIC driver for using the TCP terminal

> 2) Have you intentions to add any of these ARM platform support in 
> Genode (drivers for uart,display etc.)? The platforms above I think, are 
> more avaliable than pbx-a9.

There are no concrete plans about these platforms, yet. We use to add
drivers as needed. The incentive for supporting PBX-A9 was its great
Qemu support. Our support for the Versatile-Express platform was
motivated by a paid-for project commissioned by a client of Genode Labs.
I think, adding UART and display drivers for the platforms mentioned by
you is not too hard. If you decide to look into this topic, the existing
pl11x, pl011, and lan9118 drivers will hopefully serve you well as blue
print for creating Genode framebuffer/uart/nic drivers for Tegra or
OMAP4. Alternatively, you are welcome to commission such work to Genode
Labs. :-)

Cheers and all the best!

Norman

-- 
Dr.-Ing. Norman Feske
Genode Labs

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