Emulate Raspberry Pi zero W with Qemu failed due to missing dtb

Question

I am trying to emulate a Raspberry Pi zero W with Qemu based on an image I used on a real Raspberry Pi zero W.

The command I am using is:

sudo qemu-system-arm \                                                                                                                                                       
-kernel ./qemu-rpi-kernel/kernel-qemu-4.9.59-stretch \
-append "root=/dev/sda2 panic=1 rootfstype=ext4 rw" \
-hda pi_zero_kinetic_raspbian.qcow \
-cpu arm1176 -m 512 \
-M versatilepb \
-no-reboot \
-serial stdio \
-net nic -net user \
-net tap,ifname=vnet0,script=no,downscript=no

But Qemu complain that Error: unrecognized/unsupported machine ID (r1 = 0x00000183)

So added this option:

-dtb linux/arch/arm/boot/dts/bcm2835-rpi-zero-w.dts

But In this case:

qemu-system-arm: Unable to copy device tree in memory
Couldn't open dtb file qemu-rpi-kernel/tools/linux/arch/arm/boot/dts/bcm2835-rpi-zero-w.dts

So I tried to compile the dts in order to get the dtb with:

dtc -O dtb -o bcm2835-rpi-zero-w.dtb bcm2835-rpi-zero-w.dts

But the compilation fail and I get:

Error: bcm2835-rpi-zero-w.dts:13.1-9 syntax error
FATAL ERROR: Unable to parse input tree

I couldn't find any tutorial about Pi zero and all the tutorial about the first Rapsberry Pi seems to be outdated. I am not sure that compiling the dtb on my own is the way to go. Any input would be appreciated, thanks!

Answer 1

This works for me on MacOS Mojave,

Create a file called qemu_script.sh and copy-paste the code below

nano qemu_script.sh

give execution perms and execute,

$ chmod +x qemu_script.sh
$ ./qemu_script.sh

Code:

#!/bin/sh

brew install qemu

export QEMU=$(which qemu-system-arm)
export TMP_DIR=~/tmp/qemu-rpi
export RPI_KERNEL=${TMP_DIR}/kernel-qemu-4.14.79-stretch
export RPI_FS=${TMP_DIR}/2018-11-13-raspbian-stretch-lite.img
export PTB_FILE=${TMP_DIR}/versatile-pb.dtb
export IMAGE_FILE=2018-11-13-raspbian-stretch-lite.zip
export IMAGE=http://downloads.raspberrypi.org/raspbian_lite/images/raspbian_lite-2018-11-15/${IMAGE_FILE}

mkdir -p $TMP_DIR; cd $TMP_DIR

wget https://github.com/dhruvvyas90/qemu-rpi-kernel/blob/master/kernel-qemu-4.14.79-stretch?raw=true \
        -O ${RPI_KERNEL}

wget https://github.com/dhruvvyas90/qemu-rpi-kernel/raw/master/versatile-pb.dtb \
        -O ${PTB_FILE}

wget $IMAGE
unzip $IMAGE_FILE


$QEMU -kernel ${RPI_KERNEL} \
    -cpu arm1176 -m 256 -M versatilepb \
    -dtb ${PTB_FILE} -no-reboot \
    -serial stdio -append "root=/dev/sda2 panic=1 rootfstype=ext4 rw" \
    -drive "file=${RPI_FS},index=0,media=disk,format=raw" \
    -net user,hostfwd=tcp::5022-:22 -net nic \

You should get:

Answer 2

1. You are still using "versatilepb". If you want to emulate a Raspberry Pi, use "raspi"
2. The precompiled DTB files can be downloaded from the foundation firmware github. Direct link for the Pi Zero DTB here.

Answer 3

I share my updated version of the script for Raspbian-buster-lite guest on Ubuntu host.

#!/bin/sh

QEMU=$(command -v qemu-system-arm)
TMP_DIR=qemu-rpi
RPI_KERNEL=kernel-qemu-4.19.50-buster
RPI_KERNEL_FILE=$TMP_DIR/$RPI_KERNEL
PTB=versatile-pb.dtb
PTB_FILE=$TMP_DIR/$PTB
IMAGE_BASE=2019-09-26-raspbian-buster-lite
IMAGE=$IMAGE_BASE.zip
IMAGE_FILE=$TMP_DIR/$IMAGE
RPI_FS=$TMP_DIR/$IMAGE_BASE.img

mkdir -p $TMP_DIR

wget https://github.com/dhruvvyas90/qemu-rpi-kernel/blob/master/${RPI_KERNEL}?raw=true \
        -O ${RPI_KERNEL_FILE}

wget https://github.com/dhruvvyas90/qemu-rpi-kernel/raw/master/$PTB \
        -O ${PTB_FILE}

wget http://downloads.raspberrypi.org/raspbian_lite/images/raspbian_lite-2019-09-30/$IMAGE \
        -O ${IMAGE_FILE}
unzip $IMAGE_FILE -d $TMP_DIR


$QEMU -kernel ${RPI_KERNEL_FILE} \
    -cpu arm1176 -m 256 -M versatilepb \
    -dtb ${PTB_FILE} -no-reboot \
    -serial stdio -append "root=/dev/sda2 panic=1 rootfstype=ext4 rw" \
    -drive "file=${RPI_FS},index=0,media=disk,format=raw" \
    -net user,hostfwd=tcp::5022-:22 -net nic

Answer 4

What I did was modify the QEMU source to add support for RPi Zero W recompile. https://github.com/igwtech/qemu