Re: EVL UART driver

[Philippe Gerum <rpm@xenomai.org>]

Pierre FICHEUX <pierre.ficheux@smile.fr> writes:

> Hi all,
>
> I'm looking for information about writing such a driver. Reading
> https://v4.xenomai.org/core/drivers/index.html leads me to think there
> is nothing available for UARTs.
>
> Is there any example of documentation anywhere ?
>
> I've read a post by a french developper (Clément Godbille) but it was
> in 2021, just a short discussion with Philippe.

There is indeed no support for driving uarts from the oob stage yet. As
the document you pointed out suggests, providing such support first
requires to figure out how to properly teach the tty layer about the oob
stage, IOW how to provide a functional subset which could work from an
NMI-like context, so that we don't have to fork off any random mainline
(uart) driver to adapt it specifically for oob, with all the bit rot
issues this caused to Xenomai3 over time.

Xenomai4 already does this for the DMA, GPIO, SPI and network
subsystems, I have no doubt this could be done for the tty layer the
same way.

-- 
Philippe.