From: Søren S. C. <li...@ss...> - 2010-08-12 21:35:59
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Hi Benny, > The incoming RX frames is indicated the way you describe. Great :-) > I will try to figure out how and if I can change it to FIQ, but I'm quite new > to the "kernel Linux area" and don't know how it will work on a driver which > uses threaded interrupt (I'm using the mcp251x driver from 2.6.35). Hmm - I fear that you then won't gain anything in particular. The complete idea of using FIQ is to get priority. In case of just getting priority for scheduling some kind of DFC (thread) for doing the interesting time critical work (reading stuff from the SPI bus) with interrupts enabled later I think you might as well do nearly as good with just the current IRQ version. You would need to get the critical stuff done in the FIQ context as well as I see it, but this of cause might cause other interrupts to not be served within time - The beauty of having to serve hard real-time stuff... :-) > If I understand it correct FIQ will ensure that I arrive to my handler fast even > if the OMAP is processing a normal IRQ, but after that any IRQ will actually be > able to interrupt the handler. I'm not sure I follow you 100% on this. An FIQ can break in to a IRQ, but not the other way around. Running in FIQ context will be like running with "Interrupts off" for normal IRQs... > If thats what happens then I just have to be sure > that my handler will have priority above handlers from other IRQ's, but how or > am I way off here? I'm not sure I follow you on this either - Please try to elaborate a bit and I will try to comment I hope this helped you forward - Best regards - Good luck Søren --- SSC Solutions ApS - Denmark - www.ssc-solutions.dk |