From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4D3E5666.8040809@domain.hid> Date: Tue, 25 Jan 2011 05:49:42 +0100 From: Gilles Chanteperdrix MIME-Version: 1.0 References: <4D3E385A.5010209@domain.hid> <4D3E42BA.4000601@domain.hid> <4D3E4EBA.6050806@domain.hid> <4D3E5169.8050103@domain.hid> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-help] Segmentation Fault when writing in registers (AT91SAM - ARM9) List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: at91_enthus Cc: xenomai-help at91_enthus wrote: > On Mon, Jan 24, 2011 at 10:28 PM, Gilles Chanteperdrix < > gilles.chanteperdrix@xenomai.org> wrote: > >> at91_enthus wrote: >>> On Mon, Jan 24, 2011 at 10:16 PM, Gilles Chanteperdrix < >>> gilles.chanteperdrix@xenomai.org> wrote: >>> >>>> at91_enthus wrote: >>>>> On Mon, Jan 24, 2011 at 9:25 PM, Gilles Chanteperdrix < >>>>> gilles.chanteperdrix@xenomai.org> wrote: >>>>> >>>>>> at91_enthus wrote: >>>>>>> On Mon, Jan 24, 2011 at 8:41 PM, Gilles Chanteperdrix < >>>>>>> gilles.chanteperdrix@xenomai.org> wrote: >>>>>>> >>>>>>>> at91_enthus wrote: >>>>>>>>> Hi. >>>>>>>>> >>>>>>>>> I was testing Xenomai on my AT91SAM9G20-based board and tried to >>>> adapt >>>>>>>> the >>>>>>>>> code found here: >>>>>>>>> http://www.armadeus.com/wiki/index.php?title=Xenomai:Blinking_LEDs. >>>>>>>> By the way, this code is ridiculous. It creates a real-time task to >>>>>>>> write to some non real-time device, which makes the real-time task >>>>>> useless. >>>>>>> I know. >>>>>> Yes, but this example is bad in many ways: >>>>>> - first it uses xenomai api to create a real-time task, and uses write >>>>>> which causes the real-time task to switch to secondary domain; >>>>>> - the Makefile does not use xeno-config, which have been the >> recommended >>>>>> way of getting the compiler flags since day 1; >>>>>> - it nullifies SIGTERM and SIGINT, which is a dubious decision, and >>>>>> could lead people to believe that they should do the same when using >>>>>> Xenomai, whereas there is no such requirement. >>>>>> - the pointers point to outdated version of the documentation. >>>>>> - it uses runinfo/xeno-load, which are kind of outdated too, make >> things >>>>>> uselessly complicated, and in any case, tell you to type Ctrl-C to >>>>>> interrupt the program, which is bound to fail if anything goes wrong, >>>>>> since SIGINT is neutralized in the program. >>>>>> >>>>>>> That's why I went to mmap(). >>>>>> That is not really the right solution either. I admit that for driving >>>>>> leds, it may be a bit overkill, but anyway, what you should do is >> write >>>>>> an RTDM driver for driving the leds. Keeping the driver separated from >>>>>> the application will allow the same program to run on other platforms >>>>>> where driving the LEDS is done differently without changing much of >> the >>>>>> application code. In other word, the application/driver separation is >> a >>>>>> sane one. >>>>>> >>>>>> Anyway, mmap should work. >>>>>> >>>>>> (I chose that sample code because, for >>>>>>> now, I am only learning to use basic functions) >>>>>>>> Wrong test here. Should be "if (aic_base == MAP_FAILED)" >>>>>>> Indeed, my program fails miserably when I check the mapping of AIC, >> not >>>>>>> PIOB's. And yet, I just can't figure why in the non-Xenomai code, AIC >>>>>>> mmap-ing works fine. >>>>>> Well errno might give you a clue. Do you have FCSE enabled? >>>>>> >>>>>> Regards. >>>>>> >>>>>> -- >>>>>> >> Gilles. >>>>> FCSE is enabled. errno returns 22 (invalid argument). >>>> best effort or guaranteed? >>> >>> Best effort >>> >>> >>>> Please activate FCSE messages. >>> >>> ... compiling new kernel >>> >>> >>>> How big is >>>> MAP_SIZE? >>>> >>>> >>> 4096 >> Ok. Could you post your full kernel configuration, as well as the full >> program? >> > > I put the .config and the code in the attachments. > > >> Are you running this program as root? >> >> > I run it with sudo. Ok. Please make sure that you are not running with some funky ulimit settings then, I will try and compile it on at91sam9263. -- Gilles.