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
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