From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: In-Reply-To: <557D40F6.9000105@xenomai.org> References: <4019d695cc8c27a13bd17adc951e3ade.squirrel@sourcetrek.com> <05AD097B-C2A0-4279-A170-79385AC005B1@gmail.com> <9c648f9ec1a5abf4d783d8f3a9ada651.squirrel@sourcetrek.com> <7296329D-54C3-446C-A206-956BCBAEE441@gmail.com> <438716acfb1172076225e9266fa98c04.squirrel@sourcetrek.com> <557D40F6.9000105@xenomai.org> Date: Sun, 14 Jun 2015 10:55:38 +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: Philippe Gerum Cc: xenomai Philippe Gerum wrote: > On 06/14/2015 10:46 AM, Gilles Chanteperdrix wrote: >> >> 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/ >> > > And changes to the RTDM API brought in by the transition to xenomai 3 too. > > Well, for a test run, as a first step, I guess Michael can ignore these changes. But ultimately, I agree, this would have to be tackled. -- Gilles. https://click-hack.org