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Boot Debian from an SD Card on the SAMA5D3 Xplained

cstanton

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.image

 

Here I present the steps I took to have Debian working on the SAMA5D3, 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:

 

  • An SD card (I tend to work with at least a Class 6, 8GByte)
  • An Atmel SAMA5D3Atmel SAMA5D3 board with a Micro-A to USB-A cable (should come with the board)
  • A computer with Linux (unless you're able to translate the steps to Windows, feel free) with an internet connection
  • An FTDI 3v3 TTL type cableFTDI 3v3 TTL type cable

 

I built the SAMA5D3 image on an installation of Debian Wheezy, 64bit. Because the pre-compiled GCC compiler is 32bit you need to have the i386 architecture added and some packages installed (you'll have to find the relevant equivalent for your Linux distribution):

 

sudo dpkg --add-architecture i386

sudo apt-get update

sudo apt-get install libc6:i386 libstdc++6:i386 libncurses5:i386 zlib1g:i386 -y

 

Open up a terminal, create a directory to work in and run the following commands to grab Linaro, the ARM cross compiler:

 

    wget -c http://releases.linaro.org/latest/components/toolchain/binaries/gcc-linaro-arm-linux-gnueabihf-4.9-2014.09_linux.tar.xz
    tar x -f gcc-linaro-arm-linux-gnueabihf-4.9-2014.09_linux.tar.xz
    export CC=`pwd`/gcc-linaro-arm-linux-gnueabihf-4.9-2014.09_linux/bin/arm-linux-gnueabihf-

 

The version of the cross compiler will change as it is updated, if you don't keep up to date with it then you may discover unexpected errors as the make files below might expect a more recent version. You can grab the latest compiled binary of gcc-linaro here.

 

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}

 

If you're reading this and you have the SAMA5D3-EK, then the steps are different in which patch you get and apply (thanks mathivanan) :

 

git clone git://git.denx.de/u-boot.git

cd u-boot/

git checkout v2014.04 -b tmp

wget -c https://raw.githubusercontent.com/eewiki/u-boot-patches/master/v2014.04/0001-sama5d3xek-uEnv.txt-bootz-n-fixes.patch

patch -p1 < 0001-sama5d3xek-uEnv.txt-bootz-n-fixes.patch

make ARCH=arm CROSS_COMPILE=${CC} distclean

make ARCH=arm CROSS_COMPILE=${CC} sama5d3xek_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 (check https://rcn-ee.net/deb/minfs/wheezy/ for latest version(s)) :

 

    wget -c https://rcn-ee.net/deb/minfs/wheezy/debian-7.5-minimal-armhf-2014-07-07.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 (colon then 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!

 

The login details are:

 

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.

 

The SD Card IMG file is available here and is sized at approximately 544MByte, and an MD5 to check it against. IT Support lost the file Q_Q;

 

If you have any questions, login/register to the site and add a comment below. If I've made an error, let me know, chances are that I have.

 

I've also found alternate guides, which worked well when building on Debian Jessie.