QEMU m68k

QEMU for m68k supports a special ‘virt’ machine designed for emulation and virtualization purposes. This document describes how to run U-Boot under it.

The QEMU virt machine models a generic m68k virtual machine with Goldfish interfaces. It supports the Motorola 68040 CPU architecture.

Building U-Boot

Set the CROSS_COMPILE environment variable to your m68k toolchain, and run:

export CROSS_COMPILE=m68k-linux-gnu-
make qemu-m68k_defconfig
make

Running U-Boot

The minimal QEMU command line to get U-Boot up and running is:

qemu-system-m68k -M virt -cpu m68040 -nographic -kernel u-boot

Note that the -nographic option is used to redirect the console to stdio, which connects to the emulated Goldfish TTY device.

Debugging U-Boot

If you need early debugging output enable CONFIG_DEBUG_UART_GOLDFISH. The base address for the UART can be found by activating the QEMU monitor, running info qtree, and then looking for the goldfish tty device and taking the mmio address.

Baud rate doesn’t matter.

Hardware Support

The following QEMU virt peripherals are supported in U-Boot:

• Goldfish TTY (Serial Console)

• Goldfish RTC (Real Time Clock)