From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <438716acfb1172076225e9266fa98c04.squirrel@sourcetrek.com> In-Reply-To: <7296329D-54C3-446C-A206-956BCBAEE441@gmail.com> References: <4019d695cc8c27a13bd17adc951e3ade.squirrel@sourcetrek.com> <05AD097B-C2A0-4279-A170-79385AC005B1@gmail.com> <9c648f9ec1a5abf4d783d8f3a9ada651.squirrel@sourcetrek.com> <7296329D-54C3-446C-A206-956BCBAEE441@gmail.com> Date: Sun, 14 Jun 2015 10:46:26 +0200 From: "Gilles Chanteperdrix" MIME-Version: 1.0 Content-Type: text/plain;charset=utf-8 Content-Transfer-Encoding: 8bit Subject: Re: [Xenomai] RTDM-native mainlining - status? List-Id: Discussions about the Xenomai project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Michael Haberler Cc: xenomai Michael Haberler wrote: > >> Am 13.06.2015 um 09:19 schrieb Gilles Chanteperdrix >> : >> >> >> Michael Haberler wrote: >>> I hope I do not overlook some boundary condition - but assuming that >>> building out-of-tree RTDM support is significantly less invasive and >>> version-dependent than patching a kernel, that scheme could enormously >>> widen the range of platforms we could deploy with good results, and at >>> the >>> same time lower maintenance requirements. >> >> No, alas a Linux driver is always version-dependent, so, the driver >> would >> contain some wrappers to handle differences between version. But this is >> not something new, everybody maintaining out-of-tree Linux kernel code >> has >> been doing it for a very long time. We do it for Xenomai, even Linux >> developers are doing it for the driver backport project. > > certainly, but if the problem scope changes from "patch a specific kernel > version for full Xenomai support" to "maintain the API and support library > for a set of out-of-tree drivers on top of a stock kernel from elsewhere" > we're in a different (my guess: easier and more widely applicable) > ballgame There should not be a need for a support library, since RTDM uses the usual driver API open, read, write, ioctl, I would expect an RTDM native driver to work with the plain Linux version of these calls. > > I would really be interested in exploring this route with a simple > example, like this GPIO RTDM driver, and try to make this work with say a > vanilla or RT-PREEMPT kernel - if only to gauge feasibility, effort and > results > > what would you recommend as a starting point? Well, RTDM native is not part of Xenomai (yet), so, the first step would be to to try and compile it. The last commits in the git date back from 2007, so, some adaptation will be needed to get it running with the latest kernels. https://git.xenomai.org/rtdm-native.git/ -- Gilles. https://click-hack.org