xref: /openbmc/u-boot/doc/README.qemu-arm (revision 4e97e257)
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
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.
12
13The 'virt' platform provides the following as the basic functionality:
14
15    - A freely configurable amount of CPU cores
16    - U-Boot loaded and executing in the emulated flash at address 0x0
17    - A generated device tree blob placed at the start of RAM
18    - A freely configurable amount of RAM, described by the DTB
19    - A PL011 serial port, discoverable via the DTB
20    - An ARMv7 architected timer
21    - PSCI for rebooting the system
22    - A generic ECAM-based PCI host controller, discoverable via the DTB
23
24Additionally, a number of optional peripherals can be added to the PCI bus.
25
26Building U-Boot
27---------------
28Set the CROSS_COMPILE and ARCH=arm environment variables as usual, and run:
29
30    make qemu_arm_defconfig
31    make
32
33Running U-Boot
34--------------
35The minimal QEMU command line to get U-Boot up and running is:
36
37    qemu-system-arm -machine virt,highmem=off -bios u-boot.bin
38
39The 'highmem=off' parameter to the 'virt' machine is required for PCI to work
40in U-Boot.
41
42Additional peripherals that have been tested to work in both U-Boot and Linux
43can be enabled with the following command line parameters:
44
45- To add a Serial ATA disk via an Intel ICH9 AHCI controller, pass e.g.:
46    -drive if=none,file=disk.img,id=mydisk -device ich9-ahci,id=ahci -device ide-drive,drive=mydisk,bus=ahci.0
47- To add an Intel E1000 network adapter, pass e.g.:
48    -netdev user,id=net0 -device e1000,netdev=net0
49- To add an EHCI-compliant USB host controller, pass e.g.:
50    -device usb-ehci,id=ehci
51- To add a NVMe disk, pass e.g.:
52    -drive if=none,file=disk.img,id=mydisk -device nvme,drive=mydisk,serial=foo
53
54These have been tested in QEMU 2.9.0 but should work in at least 2.5.0 as well.
55