SiFive UART support

modulename: sifive.ko

configname: CONFIG_SERIAL_SIFIVE

Linux Kernel Configuration
└─>Device Drivers
└─>Character devices
└─>Serial drivers
└─>Device Tree and Open Firmware support
└─>SiFive UART support
In linux kernel since version 5.1 (release Date: 2019-05-05)  
Select this option if you are building a kernel for a device that
contains a SiFive UART IP block. This type of UART is present on
SiFive FU540 SoCs, among others.

source code: