ruby-x.github.io/app/views/pages/arm/qemu.html.haml
Torsten Ruger 6b3fd1533f update qemu setup
old one was wheezy based, every thing outdated
stretch has ruby2.3 out of the box
2018-04-30 15:06:36 +03:00

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= render "pages/arm/menu"
%h1= title "How to configure Qemu"
%h2 Target Pi on Mac
%p So even the idea is to run software on the Pi, not everyone has a Pi (yet :-)
%p Others, like me, prefer to develop on a laptop and not carry the Pi around.
%p For all those, this here explains how to emulate the Pi on a Mac.
%p
Even if you have a Pi,
=link_to "this explains", "remote_pi.html"
a nice way to develop with it.
%p
We'll more or less follow a
=ext_link "blog post", "https://blog.agchapman.com/using-qemu-to-emulate-a-raspberry-pi/"
i found, with small additions.
%h3 Qemu
%p
Get the Qemu. There may be other emulators out there, and i have read of armulator,
but this is what i found described and it works and is “easy enough”.
%pre
%code
:preserve
brew install qemu
%h3 Pi images
%p
Create a directory for the stuff on your mac, ie pi.
%pre
%code
mkdir pi
pi is in the gitignore, and the scripts in bin, will assume pi.
%p
Get the latest Raspian image. The
=ext_link "lite version" "https://www.raspberrypi.org/downloads/raspbian/"
without Gui is fine, and smaller.
%p
Change the file format with something like:
%pre
%code
qemu-img convert -f raw -O qcow2 2017-08-16-raspbian-stretch-lite.img raspbian-stretch-lite.qcow
So we can then resize the file, without it taking extra space
%pre
%code
qemu-img resize raspbian-stretch-lite.qcow +6G
Put the resulting file into the pi directory.
%h3 Kernel
%p
One still needs a kernel (even there is one on the image?), and Druv kindly keeps a
repository of them. Since we downloaded the stretch image, grap the
=ext_link "stretch kernel" , "https://github.com/dhruvvyas90/qemu-rpi-kernel/raw/master/kernel-qemu-4.9.59-stretch"
and also the mysterious
=ext_link "tdb file." , "https://github.com/dhruvvyas90/qemu-rpi-kernel/raw/master/versatile-pb.dtb"
Both go into the pi directory.
%h3 Boot
%p
There is quite a bit to the command line to boot the pi. There is a script in the bin
directory, but here it is:
%pre
%code
:preserve
qemu-system-arm -kernel pi/kernel-qemu-4.9.59-stretch -dtb pi/versatile-pb.dtb -cpu arm1176 -m 256 -M versatilepb -no-reboot -serial stdio -append 'root=/dev/sda2 panic=1 rootfstype=ext4 rw' -hda pi/raspbian-stretch-lite.qcow -net nic -net user,hostfwd=tcp::2222-:22
%ul
%li the cpu is what broadcom specifies, ok
%li memory is unfortunately hardcoded in the versatilepb “machine”
%li the kernel is the file name of the kernel you downloaded (or extracted)
%li raspbian.img is the image you downloaded. Renamed as it probably had the datestamp on it
%li the "-net user,hostfwd=tcp::2222-:22" redircts the port 2222 to let you log into the pi
%p So
%pre
%code
:preserve
ssh -p 2222 -l pi localhost
%p will get you “in”. Ie username pi (password raspberry is the default) and port 2222
%p Qemu bridges the network (that it emulates), and so your pi is now as connected as your mac.
%h3 Working on the pi
%p
You'll probably want to log in by ssh at some point. If for no other reason than
Ctl-C will stop the emulator when you are logged in, and not the program you are
running on the emulator. This gets old _really_ quickly.
%p
To configure the ssh server on the pi, log in and run
%pre
%code
sudo raspi-config
and enable ssh in the interface options.
There is another text on how to
=link_to "work on" , "/arm/remote_pi.html"
the pi. Off course google is good , and raspian site can help too.
%h2#links Links
%ul#selector
%li=ext_link "Post used for instructions", "https://blog.agchapman.com/using-qemu-to-emulate-a-raspberry-pi/"
%li=ext_link "stretch kernel" , "https://github.com/dhruvvyas90/qemu-rpi-kernel/raw/master/kernel-qemu-4.9.59-stretch"
%li=ext_link "Rasbian image file", "http://www.raspberrypi.org/downloads/"