[Xenomai] Send interrupt from RTDM kernel module to userspace app

[Xenomai] Send interrupt from RTDM kernel module to userspace app

[Umair Ali]

Hello, 

I need to send an interrupt from Rtdm kernel device to initiate the action in the userspace application. The interrupt will be send periodically by using kernel timers. Can someone give me the example how I can do send the interrupt from Rtdm module and read the interrupt in the userspace. I have read these articles
http://stackoverflow.com/questions/33041199/sending-realtime-signal-from-a-kernel-module-to-user-space-fails
Can anyone tell me how can I implement the above in rtdm modul. Give me example

Thanks & BR
Ali

Re: [Xenomai] Send interrupt from RTDM kernel module to userspace app

[Gilles Chanteperdrix]

On Tue, May 17, 2016 at 01:51:59PM +0000, Umair Ali wrote:
> Hello, 
> 
> I need to send an interrupt from Rtdm kernel device to initiate the action in the userspace application. The interrupt will be send periodically by using kernel timers. Can someone give me the example how I can do send the interrupt from Rtdm module and read the interrupt in the userspace. I have read these articles
> http://stackoverflow.com/questions/33041199/sending-realtime-signal-from-a-kernel-module-to-user-space-fails
> Can anyone tell me how can I implement the above in rtdm modul. Give me example

Xenomai 3 does not support asynchronous signals. You can use
synchronous signals with sigwait, but that is uselessly complicated.
What you want is probably to have the thread blocked on read() or
ioctl() and wake it up when the event you are interested in happens,
this is how drivers usually work.

-- 
					    Gilles.
https://click-hack.org

Re: [Xenomai] Send interrupt from RTDM kernel module to userspace app

[Gilles Chanteperdrix]

On Wed, May 18, 2016 at 08:45:54AM +0200, Gilles Chanteperdrix wrote:
> On Tue, May 17, 2016 at 01:51:59PM +0000, Umair Ali wrote:
> > Hello, 
> > 
> > I need to send an interrupt from Rtdm kernel device to initiate the action in the userspace application. The interrupt will be send periodically by using kernel timers. Can someone give me the example how I can do send the interrupt from Rtdm module and read the interrupt in the userspace. I have read these articles
> > http://stackoverflow.com/questions/33041199/sending-realtime-signal-from-a-kernel-module-to-user-space-fails
> > Can anyone tell me how can I implement the above in rtdm modul. Give me example
> 
> Xenomai 3 does not support asynchronous signals. You can use
> synchronous signals with sigwait, but that is uselessly complicated.
> What you want is probably to have the thread blocked on read() or
> ioctl() and wake it up when the event you are interested in happens,
> this is how drivers usually work.

You have examples in xenomai sources, see for instance ioctl
RTTST_RTIOC_INTERM_BENCH_RES in:
https://git.xenomai.org/xenomai-gch.git/tree/kernel/drivers/testing/timerbench.c?h=next

-- 
					    Gilles.
https://click-hack.org