So when I wanted to build a version of Linux for the SAMA5D3 board that wasn’t Yocto or a demonstration image, then I started to struggle to find solutions.
Then I happened upon Robert Nelson’s guide on EEWiki. However, I found that it was not as straightforward as I had hoped. A few instructions were confusing and out of order with one another.
Here I present the steps I took to have Debian working on the SAMA5D3, some are the same, others are importantly different. I also have a .IMG of the SD Card I created available.
I set this up using a laptop with Debian Linux installed; I imagine it doesn’t matter which version of Linux you have; you could probably use Cygwin on windows.
You will need:
Open up a terminal, create a directory to work in and run the following commands to grab Linaro, the ARM cross compiler:
wget -c https://releases.linaro.org/14.03/components/toolchain/binaries/gcc-linaro-arm-linux-gnueabihf-4.8-2014.03_linux.tar.xz
tar xf gcc-linaro-arm-linux-gnueabihf-4.8-2014.03_linux.tar.xz
export CC=`pwd`/gcc-linaro-arm-linux-gnueabihf-4.8-2014.03_linux/bin/arm-linux-gnueabihf-
Then test the version of gcc:
${CC}gcc --version
Which should output something like this:
arm-linux-gnueabihf-gcc (crosstool-NG linaro-1.13.1-4.8-2014.03 - Linaro GCC 2014.03) 4.8.3 20140303 (prerelease)
Copyright (C) 2013 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Now we need to grab U-Boot and patch it for the SAMA5D3, you will need to have GIT installed on your distribution of Linux:
git clone git://git.denx.de/u-boot.git
cd u-boot/
git checkout v2014.04 -b tmp
wget -c https://raw.github.com/eewiki/u-boot-patches/master/v2014.04/0001-sama5d3_xplained-uEnv.txt-bootz-n-fixes.patch
patch -p1 < 0001-sama5d3_xplained-uEnv.txt-bootz-n-fixes.patch
make ARCH=arm CROSS_COMPILE=${CC} distclean
make ARCH=arm CROSS_COMPILE=${CC} sama5d3_xplained_mmc_config
make ARCH=arm CROSS_COMPILE=${CC}
Now time to build a kernel for the board!
git clone https://github.com/RobertCNelson/armv7_devel.git
cd armv7_devel/
As of the time of writing the current mainline kernel was v3.14:
git checkout origin/v3.14.x-sama5-armv7 -b tmp
./build_kernel.sh
After the kernel has compiled, you’re presented with a menu config screen where you can include or build additional modules. For example, you can incorporate GSPCA webcam support.
Now, we want to acquire the root system files for Debian, which are handily available:
wget -c https://rcn-ee.net/deb/minfs/wheezy/debian-7.4-minimal-armhf-2014-04-01.tar.xz
tar x -f debian-7.4-minimal-armhf-2014-04-01.tar.xz
Then insert your SDCard, either using a USB SDCard reader or one on your computer if you have one. I had to use a USB SDCard reader. In Linux we can type “dmesg” at a terminal to give us the /dev/ information for the device we’ve plugged in (for example mine’s /dev/sdb), in the following examples, we use mmcblk0, so just replace it for your relevant device id.
In the following steps we will erase the SDCard and set it up with the relevant partitions:
export DISK=/dev/mmcblk0
sudo dd if=/dev/zero of=${DISK} bs=1M count=16
sudo sfdisk --in-order --Linux --unit M ${DISK} < <-__EOF__
1,48,0xE,*
,,,-
__EOF__
If the linux system you're using identifies the device as something similar to mmcblk0 then to format and mount, execute:
sudo mkfs.vfat -F 16 ${DISK}p1 -n boot
sudo mkfs.ext4 ${DISK}p2 -L rootfs
sudo mkdir -p /media/boot/
sudo mkdir -p /media/rootfs/
sudo mount ${DISK}p1 /media/boot/
sudo mount ${DISK}p2 /media/rootfs/
Else if the device identifies itself as something similar to sdb then to format and mount, execute:
sudo mkfs.vfat -F 16 ${DISK}1 -n boot
sudo mkfs.ext4 ${DISK}2 -L rootfs
sudo mkdir -p /media/boot/
sudo mkdir -p /media/rootfs/
sudo mount ${DISK}1 /media/boot/
sudo mount ${DISK}2 /media/rootfs/
Note: You may not need to mount the partitions as new(ish/er) distributions tend to automatically mount partitions upon detection/insertion/creation.
Create a text file using your editor of choice (for the record I prefer vi …) called uEnv.txt and put in it the following, the sama board uses the ‘mmc’ naming convention:
optargs=quiet init=/lib/systemd/systemd
console=ttyS0,115200
mmcroot=/dev/mmcblk0p2 ro
mmcrootfstype=ext4 rootwait fixrtc
Now we’ll extract and copy across all of the necessary files, the locations should all be relative to the initial directory we’ve been working in and you created, they should all be executed as root/sudo:
sudo cp -v ./u-boot/spl/u-boot-spl.bin /media/boot/BOOT.BIN
sudo cp -v ./u-boot/u-boot.img /media/boot/
sudo cp -v ./uEnv.txt /media/boot/
sudo tar -xvp --same-owner --numeric-owner -f ./debian-0.4-minimal-armhf-2014-04-01/armhf-rootfs-debian-wheezy.tar -C /media/rootfs
sudo cp -v ./armv7_devel/deploy/3.14.0-sama5-armv7-r9.zImage /media/boot/zImage
sudo mkdir -p /media/boot/dtbs/
sudo tar xvo -f 3.14.0-sama5-armv7-r9-dtbs.tar.gz -C /media/boot/dtbs
sudo tar xv -f 3.14.0-sama5-armv7-r9-modules.tar.gz -C /media/rootfs
And to setup the partition mounting (if you don’t like vi, replace with nano, emacs or whatever your preferred editor is):
sudo vi /media/rootfs/etc/fstab
Insert into it (in vi, press ‘i’ on your keyboard, then type it in, or copy/paste it into your terminal window):
/dev/mmcblk0p2 / auto errors=remount-ro 0 1
/dev/mmcblk0p1 /boot/uboot auto defaults 0 2
Close and save the file (in vi, press ESC then type in :x and hit enter, which saves and quits).
Then setup the network interfaces:
sudo vi /media/rootfs/etc/network/interfaces
With the following at the end of the file (you can use your cursor keys to navigate vi until you get to where you want to insert):
allow-hotplug eth0
iface eth0 inet dhcp
allow-hotplug eth1
iface eth1 inet dhcp
And setup our serial line:
sudo vi /media/rootfs/etc/inittab
With the following at the end of the file:
T0:23:respawn:/sbin/getty -L ttyS0 115200 vt102
Now we want to unmount our SD Card, so close down any windows/open files that’re on the card and run the following from a terminal:
sync
sudo umount /media/boot
sudo umount /media/rootfs
Our SD Card should be setup! The only thing to do now, is remove the jumper at JP5 on the SAMA5D3 to ensure it’ll boot from the SD Card, connect a serial cable to the debug header J23 so we can see what it’s doing, with the settings in minicom/Putty/your terminal editor of choice:
Baud: 115200
Data Bits: 8
Stop Bits: 1
Parity: None
Flow Control: None
Then connect the USB cable to power the board, then press the reset button for good measure and watch it boot up!
Login details:
User: root
Pass: root
User: debian
Pass: temppwd
When I created this image from scratch initially I encountered a number of problems. The main part is that the SD Card needs to be setup as root, with the files copied over as root. This is because of the permission level required to read the SD Card when the SAMA5D3 board loads up.
The other problem I encountered was the settings for uEnv were confusing me on the eewiki guide.
Something that might trip up anyone following this guide word for word in future is if the kernel version increases, this will need to be altered in the filenames in the guide above. Failing that, the SD Card img I have prepared should help:
Debian-SAMA5D3-140409.zip (543mB)
Debian-SAMA5D3-140409.md5 (211b)