"/dev/hwrng: No such file or directory" on rk3399 chip

[ghost]

Hi! Any ideas about /dev/hwrng link to hardware random number generator? My environment: OrangePi 4+armbian buster+kernel 4.4.213

root@orangepi4:~# cat /dev/hwrng | rngtest -c 1000
cat: /dev/hwrng: No such device
rngtest 2-unofficial-mt.14
Copyright (c) 2004 by Henrique de Moraes Holschuh
This is free software; see the source for copying conditions.  There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

rngtest: starting FIPS tests...
rngtest: entropy source exhausted!

root@orangepi4:~# udevadm info -a -n /dev/hwrng

Udevadm info starts with the device specified by the devpath and then
walks up the chain of parent devices. It prints for every device
found, all possible attributes in the udev rules key format.
A rule to match, can be composed by the attributes of the device
and the attributes from one single parent device.

  looking at device '/devices/virtual/misc/hw_random':
    KERNEL=="hw_random"
    SUBSYSTEM=="misc"
    DRIVER==""
    ATTR{rng_available}=="tpm-rng "
    ATTR{rng_current}=="tpm-rng"