1# 2# Copyright (C) 2017, Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi> 3# 4# SPDX-License-Identifier: GPL-2.0+ 5# 6 7U-Boot on QEMU's 'virt' machine on ARM & AArch64 8================================================ 9 10QEMU for ARM supports a special 'virt' machine designed for emulation and 11virtualization purposes. This document describes how to run U-Boot under it. 12Both 32-bit ARM and AArch64 are supported. 13 14The 'virt' platform provides the following as the basic functionality: 15 16 - A freely configurable amount of CPU cores 17 - U-Boot loaded and executing in the emulated flash at address 0x0 18 - A generated device tree blob placed at the start of RAM 19 - A freely configurable amount of RAM, described by the DTB 20 - A PL011 serial port, discoverable via the DTB 21 - An ARMv7/ARMv8 architected timer 22 - PSCI for rebooting the system 23 - A generic ECAM-based PCI host controller, discoverable via the DTB 24 25Additionally, a number of optional peripherals can be added to the PCI bus. 26 27Building U-Boot 28--------------- 29Set the CROSS_COMPILE environment variable as usual, and run: 30 31- For ARM: 32 make qemu_arm_defconfig 33 make 34 35- For AArch64: 36 make qemu_arm64_defconfig 37 make 38 39Running U-Boot 40-------------- 41The minimal QEMU command line to get U-Boot up and running is: 42 43- For ARM: 44 qemu-system-arm -machine virt,highmem=off -bios u-boot.bin 45 46- For AArch64: 47 qemu-system-aarch64 -machine virt,highmem=off -cpu cortex-a57 -bios u-boot.bin 48 49The 'highmem=off' parameter to the 'virt' machine is required for PCI to work 50in U-Boot. Also, for some odd reason qemu-system-aarch64 needs to be explicitly 51told to use a 64-bit CPU or it will boot in 32-bit mode. 52 53Additional peripherals that have been tested to work in both U-Boot and Linux 54can be enabled with the following command line parameters: 55 56- To add a Serial ATA disk via an Intel ICH9 AHCI controller, pass e.g.: 57 -drive if=none,file=disk.img,id=mydisk -device ich9-ahci,id=ahci -device ide-drive,drive=mydisk,bus=ahci.0 58- To add an Intel E1000 network adapter, pass e.g.: 59 -netdev user,id=net0 -device e1000,netdev=net0 60- To add an EHCI-compliant USB host controller, pass e.g.: 61 -device usb-ehci,id=ehci 62- To add a NVMe disk, pass e.g.: 63 -drive if=none,file=disk.img,id=mydisk -device nvme,drive=mydisk,serial=foo 64 65These have been tested in QEMU 2.9.0 but should work in at least 2.5.0 as well. 66