[U-Boot] Periodic task

Hello,

I need to do some periodic very simple task during u-boot prompt (while u-boot wais for commands). The task is very simple, just writing into a watchdog refresh register. But it seems that it's very difficult to "hack" u-boot with such periodic task. I see that main loop is waiting in loop for characters in a call to getc, which is a blocking command. If it was non-blocking, it might have help me. I'm not sure if there is a way to replace the getc with a non-blocking call.

Does anyone have any idea if there is some simple way to do periodic task in u-boot ?

Regards,

Ran