kernelconfig_penguin
CONFIG_DEBUG_AT91_UART is not available for the default architecture x86.
Result is shown for architecture arm

Kernel low-level debugging on Atmel SoCs

configname: CONFIG_DEBUG_AT91_UART

Kernel low-level debugging port
└─> Kernel low-level debugging on Atmel SoCs

Say Y here if you want the debug print routines to direct
their output to the serial port on atmel devices.

SOC DEBUG_UART_PHYS DEBUG_UART_VIRT PORT
rm9200, 9260/9g20, 0xfffff200 0xfefff200 DBGU
9261/9g10, 9rl
9263, 9g45, sama5d3 0xffffee00 0xfeffee00 DBGU
sama5d4 0xfc00c000 0xfb00c000 USART3
sama5d4 0xfc069000 0xfb069000 DBGU
sama5d2 0xf8020000 0xf7020000 UART1

Please adjust DEBUG_UART_PHYS configuration options based on
your needs.