at91_enthus wrote:
> On Mon, Jan 24, 2011 at 10:16 PM, Gilles Chanteperdrix <
> [email protected]> wrote:
>
>> at91_enthus wrote:
>>> On Mon, Jan 24, 2011 at 9:25 PM, Gilles Chanteperdrix <
>>> [email protected]> wrote:
>>>
>>>> at91_enthus wrote:
>>>>> On Mon, Jan 24, 2011 at 8:41 PM, Gilles Chanteperdrix <
>>>>> [email protected]> 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 - the pointers point to outdated version of the documentation.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 - it uses runinfo/xeno-load, which are kind of outdated too, make things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?
Are you running this program as root?
--
Gilles.
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