Linux RTAI and Xillybus Module

Questions and discussions about the Xillybus IP core and drivers

Linux RTAI and Xillybus Module

Postby Guest » Thu Aug 10, 2017 11:53 am


i want to get a hard real time communication between FPGA and Linux Host through PCIe. I used the Xillybus example succsessfully. Now i want to upgrade to real time communication with the RTAI module. im new to this theme and maybe you can help me with some questions.

i have 3 ideas, but maybe some are rubbish.
1: Create a real time fifo from the RTAI Module to the /dev file of xillybus.
2: Create a real time fifo from the RTAI Module to the Xillyus_pcie Modul
3: Somehow insert the Xillybus_core and Xillybus_pcie code in a RTAI Module

Maybe someone can tell, what way i shoud focus on? Or maybe there is some better way to get it running?


Re: Linux RTAI and Xillybus Module

Postby support » Thu Aug 10, 2017 12:25 pm


I'm not familiar with RTAI, but I suppose that the name of the game is interrupt latency and the scheduling latency of the process that is woken up by the interrupt service routine.

So this boils down to how hard real-time constraints are enforced on these. If you need to make modifications Xillybus' driver for Linux, the sources are available of course.

Other than that, I can't comment much. But frankly, I would expect no software hacking required. I mean, enforcing the latency of an interrupt has nothing to do with the driver registered to it, and neither has enforcing scheduling of a process. But this is up to how RTAI is designed and used.

Hoped this helped a bit.
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