[Xenomai] Xenomai-3: RTDM with Mercury?

[Jeff Webb <jeff.webb@nta-inc.net>]

 From the recent traffic on the mailing list, and the website makeover, it sounds like Xenomai 3 is close to maturity, so I am trying to become familiar with the new technology.  I am very interested in the idea of having one code base that can be used in Linux, PREEMPT-RT, and dual-kernel applications.  Even with Xenomai 2, I have moved close to this goal by using the POSIX skin and using compiler directives to build my code as a standard linux application, or a real-time Xenomai version.

The main thing I am missing now is a unified interface to hardware devices, and it sounds like Xenomai 3 might be able to provide that.  From the introduction on the web site ( http://xenomai.org/introducing-xenomai-3/ ), it sounds like I should be able to use RTDM drivers with the standard linux kernel through the Mercury core.  How does this work?  Figure 3 shows a "native RTDM" block.  Is this block a kernel module that translates RTDM-specific calls into standard linux calls?  Does the translation happen at compile time or run-time?  Is there documentation on how I can write an RTDM driver that will work with both the Cobalt and Mercury cores?  For starters, can I access the 16550 RTDM driver from mercury?

I apologize if all of this is documented, and I've just missed it.  I also realize that Xenomai 3 is a work in progress and you haven't gotten to everything yet.  The documentation you have is very good, and I appreciate all the work you have put into it.

Thanks,

Jeff