Console on IMX serial port

configname: CONFIG_SERIAL_IMX_CONSOLE

Linux Kernel Configuration
└─>Device Drivers
└─>Character devices
└─>Serial drivers
└─>Console on IMX serial port
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
If you have enabled the serial port on the Freescale IMX
CPU you can make it the console by answering Y to this option.

Even if you say Y here, the currently visible virtual console
(/dev/tty0) will still be used as the system console by default, but
you can alter that using a kernel command line option such as
"console=ttymxc0". (Try "man bootparam" or see the documentation of
your bootloader about how to pass options to the kernel at boot time.)