Hello, I have also a problem with kernel freeze on BananaPro (4.14.18-sunxi #24 SMP Fri Feb 9 16:24:32 CET 2018 armv7l GNU/Linux; Debian 9) after one day.
I found few kernel messages:
dmesg -w
...
[58771.275977] brcmfmac: brcmf_psm_watchdog_notify: PSM's watchdog has fired!
[67404.029617] brcmfmac: brcmf_psm_watchdog_notify: PSM's watchdog has fired!
...
from wifi driver: brcmfmac
Is this possibly the cause of the kernel freeze?