Reboot command not working

Hi,

Build u540 image using yocto, copied the image to SD card.

System booted successfully and when running reboot command, Hi-Five unleashed board is not rebooting.

Does latest Linux kernel has support for reboot driver

Does OpenSBI has support for reboot

Tried with kernel versions 5.4.27 and 5.6.2 still reboot command not working.

Can anyone help me

Thanks
Sadiq