Getting started with Fedora on the 96boards Dragonboard

Support for this board has been a long time coming, it was originally announced in March 2015 and shipped later that summer. Two years on we can finally add support for it to Fedora. The enablement here will also assist us with supporting the newly announced 600c and 820c boards more quickly. We’re not all the way there yet, there’s still some firmwares that needs to go upstream into linux-firmware, but the improvement is fantastic and it’s been a pleasure working with the 96boards and Qualcomm teams getting to where we are today.

At the moment we support running Fedora off either an micro SD card or a USB stick. We don’t currently support running off the eMMC and currently basically treat that as the location of the firmware. Anyway lets get started!

Updating the firmware

You’ll want to update to the latest firmwares, my board originally had an old firmware without support for PSCI and so it didn’t bring up all four cores or support reboot. OOPS! You’ll need the latest linux rescue images from the 96boards download site. As I write this the latest is the 17.09 release (version 88). Create a directory for this file before you unzip it because it’ll expand all into the current directory. While there we also need a u-boot build that’s prepared for flashing, the upstream support isn’t quite complete, we add a few patches to the Fedora build to get everything working nicely. You can grab a pre-built version here and also get LK firmware build which enables display output.

You’ll need a host with the fastboot utility, in Fedora this is found in the android-tools package, and a micro USB cable. This process is very similar to flashing a phone with a new image, not surprising given the chipset really. If you have a serial console on the board you can follow along on the console but it’s not required for this board.

To put the board into fastboot mode we hold down the volume down button, labeled as ‘(-)’ near the middle USB port and then power it on. Wait around 30 seconds to ensure it’s booted to fastboot. You can test this with the fastboot devices command. You’ll likely want to run the next commands as root, or use sudo, and be in the directory you created with the extracted firmware and u-boot build:

sudo ./flashall
sudo fastboot flash aboot emmc_appsboot.mbn
sudo fastboot flash boot u-boot.img
sudo fastboot oem select-display-panel adv7533_1080p

The flashall command runs a series of fastboot command to write out various early boot firmware to the eMMC, then we write u-boot out to the boot partition, and finally ensure that output is configured to appear on the HDMI port. Assuming you don’t get any errors from fastboot that should be all the firmware done and in place.

Fedora image and further setup

Next up is the Fedora image. I chose the Workstation image, but we also have a Minimal Image and a traditional Server image. GNOME not the fastest in the world as 1Gb of RAM isn’t really enough for GNOME-3 anymore, but it works well enough. On a USB stick or Micro-SD card (I’ve tried both). We need to write out the image, then expand the rootfs (Note: update XXX for the device you’re writing to):

xzcat Fedora-Workstation-27-1.6.aarch64.raw.xz | sudo dd status=progress bs=4M of=/dev/XXX
sudo gparted /dev/XXX (expand the last partition)
partprobe

Next up we need to adjust the kernel command line slightly, mount up the first partition and edit /EFI/fedora/grub.cfg and search for the string cma=256MB and delete it, then add in it’s place the following console=tty1 console=ttyMSM0,115200n8. Next mount the boot partition (partition 2) and create a sym link

ln -s dtb-4.13.9-300.fc27.aarch64 dtb

. Unmount the partitions and we should be good to go on the Dragonboard.

Plug in a keyboard, mouse (and/or a usb cable for the serial console if you’re going that route) and a HDMI cable, plug in the USB stick or SD card and power it up. If you’re following along on the serial console you should see output straight away, screen might take a little longer.

Once you’ve booted you should be able to complete initial-setup (text or the one from Workstation) and login. To get the WiFI and Bluetooth working you need to install a Radio (WiFi and friends) firmware package which I’ve made into a rpm you can grab from here until it lands into linux-firmware.

What next?

The DragonBoard 410c is pretty functional. I’ve not widely tested sound, the Venus media offload components (we have all the firmware and kernel bits for this), the GPS or some of the other more advanced components but I’ll have more details about those soon. I’ll be documenting the above plus other bits on the Fedora ARM wiki so keep an eye on that or get involved and help out 😛

Getting started with Zephyr on Fedora

So while Fedora is great for a lot of IoT use cases it can’t be used everywhere, such as on tiny micro controllers such as an ARM Cortex-M series or Intel Quark micro controllers, but that doesn’t mean that Fedora doesn’t make a fantastic developer platform for working with these devices.

I have a handful of Zephyr capable devices (BBC Micro:bit, NXP FRDM-K64F, 96Boards Carbon, TI CC3200 LaunchPad) so how can you get a build environment up and running quickly so you can start doing real development as quickly as possible.

In testing this I used a Digital Ocean cloud instance for a build host. Wherever you choose to build it make sure you have at least 2GB of RAM available as from my experience you need at least 2GB for building a Zephyr image.

From there we diverge a little from the upstream notes by installing the Fedora ARM cross compiler (only tested with ARM, not sure of state of other targets) and developer tools:

sudo dnf install git-core gcc gcc-arm-linux-gnu glibc-static libstdc++-static make dfu-util dtc python3-PyYAML

Next up we clone the upstream Zephyr git repository:

git clone https://gerrit.zephyrproject.org/r/zephyr zephyr-project

If we want to use a particular stable branch we now switch to the chosen branch. I’m using the latest stable release branch:

cd zephyr-project; git checkout v1.7-branch

Set up the cross compiler variables:

export GCCARMEMB_TOOLCHAIN_PATH="/usr"
source zephyr-env.sh
cd $ZEPHYR_BASE/samples/hello_world

Select and build our target:

make CROSS_COMPILE="/usr/bin/arm-linux-gnu-" DTC=/usr/bin/dtc BOARD=96b_carbon

If we’re developing this on our local machine we can now just directly flash the new build straight to the device. To do this we connect a micro USB cable to the USB OTG port on the Carbon and to your computer. The board should power on. Force the board into DFU mode by keeping the BOOT0 switch pressed while pressing and releasing the RST switch.

Confirm DFU can see the device:

$ sudo dfu-util -l
dfu-util 0.9

Copyright 2005-2009 Weston Schmidt, Harald Welte and OpenMoko Inc.
Copyright 2010-2016 Tormod Volden and Stefan Schmidt
This program is Free Software and has ABSOLUTELY NO WARRANTY
Please report bugs to http://sourceforge.net/p/dfu-util/tickets/

Found DFU: [0483:df11] ver=2200, devnum=8, cfg=1, intf=0, path="2-1", alt=3, name="@Device Feature/0xFFFF0000/01*004 e", serial="123456789"
Found DFU: [0483:df11] ver=2200, devnum=8, cfg=1, intf=0, path="2-1", alt=2, name="@OTP Memory /0x1FFF7800/01*512 e,01*016 e", serial="123456789"
Found DFU: [0483:df11] ver=2200, devnum=8, cfg=1, intf=0, path="2-1", alt=1, name="@Option Bytes  /0x1FFFC000/01*016 e", serial="123456789"
Found DFU: [0483:df11] ver=2200, devnum=8, cfg=1, intf=0, path="2-1", alt=0, name="@Internal Flash  /0x08000000/04*016Kg,01*064Kg,03*128Kg", serial="123456789"

Flash our build onto the device:

sudo dfu-util -d [0483:df11] -a 0 -D outdir/96b_carbon/zephyr.bin -s 0x08000000

Now connect another micro USB cable to the UART port and run a console:

sudo screen /dev/ttyUSB0 115200

Hit the reset button and you should see the following output:

***** BOOTING ZEPHYR OS v1.7.1 - BUILD: Jun  6 2017 14:07:24 *****
Hello World! arm

Now we have a basic development environment setup, know we can build, flash and run a release on the 96boards Carbon next time we can do something more advanced 😉

Update (2017-06-13): Minor updates to dependency installs and make command