[ofa-general] synchronize commands issued to MTHCA

[Roland Dreier]

 > Roland, do you think that the memcpy_toio() call might mess things up?

I wouldn't think so, although I don't have full details of how your
hardware behaves to know for sure.  I assume your PCI bus/memory
controller is already smart enough to deal with HCR writes being
interleaved with writes to a doorbell page from userspace, so it seems
that writes to locally attached memory should be OK too, as long as
the HCR writes are word-sized in the right order etc.

 > Maybe we need "wmb()" or "mmiowb()" here as well?

I don't see any reason, although I often miss things.  It seems that
the only thing that cares about the writes of the address info being
done would be posting a send WQE that uses it, and that should already
have sufficient ordering.  What would we be ordering things against?

 - R.