xref: /openbmc/u-boot/doc/README.qemu-arm (revision 0bdea7c4) 
1# SPDX-License-Identifier: GPL-2.0+
2#
3# Copyright (C) 2017, Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
4
5U-Boot on QEMU's 'virt' machine on ARM & AArch64
6================================================
7
8QEMU for ARM supports a special 'virt' machine designed for emulation and
9virtualization purposes. This document describes how to run U-Boot under it.
10Both 32-bit ARM and AArch64 are supported.
11
12The 'virt' platform provides the following as the basic functionality:
13
14    - A freely configurable amount of CPU cores
15    - U-Boot loaded and executing in the emulated flash at address 0x0
16    - A generated device tree blob placed at the start of RAM
17    - A freely configurable amount of RAM, described by the DTB
18    - A PL011 serial port, discoverable via the DTB
19    - An ARMv7/ARMv8 architected timer
20    - PSCI for rebooting the system
21    - A generic ECAM-based PCI host controller, discoverable via the DTB
22
23Additionally, a number of optional peripherals can be added to the PCI bus.
24
25Building U-Boot
26---------------
27Set the CROSS_COMPILE environment variable as usual, and run:
28
29- For ARM:
30    make qemu_arm_defconfig
31    make
32
33- For AArch64:
34    make qemu_arm64_defconfig
35    make
36
37Running U-Boot
38--------------
39The minimal QEMU command line to get U-Boot up and running is:
40
41- For ARM:
42    qemu-system-arm -machine virt -bios u-boot.bin
43
44- For AArch64:
45    qemu-system-aarch64 -machine virt -cpu cortex-a57 -bios u-boot.bin
46
47Note that for some odd reason qemu-system-aarch64 needs to be explicitly
48told to use a 64-bit CPU or it will boot in 32-bit mode.
49
50Additional peripherals that have been tested to work in both U-Boot and Linux
51can be enabled with the following command line parameters:
52
53- To add a Serial ATA disk via an Intel ICH9 AHCI controller, pass e.g.:
54    -drive if=none,file=disk.img,id=mydisk -device ich9-ahci,id=ahci -device ide-drive,drive=mydisk,bus=ahci.0
55- To add an Intel E1000 network adapter, pass e.g.:
56    -netdev user,id=net0 -device e1000,netdev=net0
57- To add an EHCI-compliant USB host controller, pass e.g.:
58    -device usb-ehci,id=ehci
59- To add a NVMe disk, pass e.g.:
60    -drive if=none,file=disk.img,id=mydisk -device nvme,drive=mydisk,serial=foo
61
62These have been tested in QEMU 2.9.0 but should work in at least 2.5.0 as well.
63