On 07/24/2017 01:39 PM, Alexey Brodkin wrote: > Hi Alexandru, > >> I'm getting a storm of these messages when trying to boot an in-house >> ASIC with an ARC770. This only happens with an ethernet cable plugged >> in. I've learned that the actual interrupt number is 21. The issue is >> that the irq_find_mapping() in __handle_domain_irq() fails to find a >> mapping for vector 21, and the remaining logic will brainlessly print >> out '0' as the interrupt number (which is of course, bass-ackwards). [snip] > That's interesting! I saw exactly the same issue with one of our devboards. > What happens here is GMAC generates output interrupt because of some > condition(s), I'm seeing this when using U-boot to load the kernel over ethernet. I think it's enough to have the PHY link autonegotiated to get the problem, but I didn't verify this. > Answering your question why interrupt from GMAC happens before its driver > is probed: > 1) I need to look at my notes I made when was fighting with the same problem, > but for some reason DW GMAC seems to have interrupts enabled on reset > which is indeed a bit unexpected and might lead to a behavior you and I saw. I'm curious to know what your notes say. > 2) Historically we used to enable all possible core IRQ lines early on boot as opposed > to per-line init by request of each particular driver. We have this on our to-do list > as one of important improvements but that's not a short-term fix for sure. > > A work-around that I made and which may recommend to you is to figure out what > condition in GMAC leads to generation of interrupt on its out and then resetting it in > GMAC in your early platform boot code. I was afraid that might be the only way. I can keep the GMAC logic in reset, but that requires a custom platform early_init(), and a glue driver for snps,dwmac. > Let me know if it helps. Yes. I implemented the proof-of-concept today. It's a very "interesting" balancing act on when exactly to release the reset on the GMAC. I'm able to get to boot to a shell with ethernet plugged in. Alex
