Console on RDA Micro serial port

configname: CONFIG_SERIAL_RDA_CONSOLE

Linux Kernel Configuration
└─>Device Drivers
└─>Character devices
└─>Serial drivers
└─>Console on RDA Micro serial port
In linux kernel since version 5 (release Date: 2019-03-03)  
Say 'Y' here if you wish to use the RDA8810PL UART as the system
console. Only earlycon is implemented currently.