How to disable the Linux console port?

I'd like to disable the linux console port when booting up Linux, such the port (/dev/ttymxc1) becomes available for regular serial communication with serial peripherals.

Thanks for your support,

Didier.

This doesn't seem to work:

1. setenv console=ttynull returns a syntax error (= is not allowed). setenv console ttynull is accepted.

2. but even after this change, the console is not disabled on /dev/ttyxmc1: the kernel boot messages still appear on that port and a console prompt to login is still shown.

Thanks again for the support.

Didier.