1.. SPDX-License-Identifier: GPL-2.0+
2.. Copyright (C) 2021, Bin Meng <bmeng.cn@gmail.com>
3
4QEMU PPC E500
5=============
6
7QEMU for PPC supports a special 'ppce500' machine designed for emulation and
8virtualization purposes. This document describes how to run U-Boot under it.
9
10The QEMU ppce500 machine models a generic PowerPC E500 virtual machine with
11support for the VirtIO standard networking device connected to the built-in
12PCI host controller. Some common devices in the CCSBAR space are modeled,
13including MPIC, 16550A UART devices, GPIO, I2C and PCI host controller with
14MSI delivery to MPIC. It uses device-tree to pass configuration information
15to guest software.
16
17Building U-Boot
18---------------
19Set the CROSS_COMPILE environment variable as usual, and run::
20
21    $ make qemu-ppce500_defconfig
22    $ make
23
24Running U-Boot
25--------------
26The minimal QEMU command line to get U-Boot up and running is::
27
28    $ qemu-system-ppc -nographic -machine ppce500 -bios u-boot
29
30You can also run U-Boot using 'qemu-system-ppc64'::
31
32    $ qemu-system-ppc64 -nographic -machine ppce500 -bios u-boot
33
34The commands above create a target with 128 MiB memory by default. A freely
35configurable amount of RAM can be created via the '-m' parameter. For example,
36'-m 2G' creates 2 GiB memory for the target, and the memory node in the
37embedded DTB created by QEMU reflects the new setting.
38
39Both qemu-system-ppc and qemu-system-ppc64 provide emulation for the following
4032-bit PowerPC CPUs:
41
42* e500v2
43* e500mc
44
45Additionally qemu-system-ppc64 provides support for the following 64-bit CPUs:
46
47* e5500
48* e6500
49
50The CPU type can be specified via the '-cpu' command line. If not specified,
51it creates a machine with e500v2 core. The following example shows an e6500
52based machine creation::
53
54    $ qemu-system-ppc64 -nographic -machine ppce500 -cpu e6500 -bios u-boot
55
56When U-Boot boots, you will notice the following::
57
58    CPU:   Unknown, Version: 0.0, (0x00000000)
59    Core:  e6500, Version: 2.0, (0x80400020)
60
61This is because we only specified a core name to QEMU and it does not have a
62meaningful SVR value which represents an actual SoC that integrates such core.
63You can specify a real world SoC device that QEMU has built-in support but all
64these SoCs are e500v2 based MPC85xx series, hence you cannot test anything
65built for P4080 (e500mc), P5020 (e5500) and T2080 (e6500).
66
67By default a VirtIO standard PCI networking device is connected as an ethernet
68interface at PCI address 0.1.0, but we can switch that to an e1000 NIC by::
69
70    $ qemu-system-ppc -nographic -machine ppce500 -bios u-boot \
71                      -nic tap,ifname=tap0,script=no,downscript=no,model=e1000
72
73VirtIO BLK driver is also enabled to support booting from a disk image where
74a kernel image is stored. Append the following to QEMU::
75
76    -drive file=disk.img,format=raw,id=disk0 -device virtio-blk-pci,drive=disk0
77
78Pericom pt7c4338 RTC is supported so we can use the 'date' command::
79
80    => date
81    Date: 2021-02-18 (Thursday)    Time: 15:33:20
82
83Additionally, 'poweroff' command is supported to shut down the QEMU session::
84
85    => poweroff
86    poweroff ...
87
88These have been tested in QEMU 5.2.0.
89