path: root/en/hardware/supported/arm.xml

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  <sect2 arch="arm"><title>Three different ARM ports</title>

<para>
The ARM architecture has evolved over time and modern ARM processors
provide features which are not available in older models.  &debian;
therefore provides three ARM ports to give the best support for a very
wide range of different machines:
<itemizedlist>
  <listitem><para>
    &debian;/armel targets older 32-bit ARM processors without support
    for a hardware floating point unit (FPU),
  </para></listitem>
  <listitem><para>
    &debian;/armhf works only on newer 32-bit ARM processors which
    implement at least the ARMv7 architecture with version 3 of the
    ARM vector floating point specification (VFPv3). It makes use of
    the extended features and performance enhancements available on
    these models.
  </para></listitem>
  <listitem><para>
    &debian;/arm64 works on 64-bit ARM processors which implement at
    least the ARMv8 architecture.
  </para></listitem>
</itemizedlist>
</para>

<para>
Technically, all currently available ARM CPUs can be run in either
endian mode (big or little), but in practice the vast majority use
little-endian mode. All of &debian;/arm64, &debian;/armhf and
&debian;/armel support only little-endian systems.
</para>

  </sect2>

  <sect2 arch="arm"><title>Variations in ARM CPU designs and support complexity</title>

<para>
ARM systems are much more heterogeneous than those based on the
i386/amd64-based PC architecture, so the support situation can be much
more complicated.
</para>

<para arch="armel;armhf">
The ARM architecture is used mainly in so-called
<quote>system-on-chip</quote> (SoC) designs. These SoCs are designed
by many different companies with vastly varying hardware components
even for the very basic functionality required to bring the system
up. System firmware interfaces have been increasingly standardised
over time, but especially on older hardware firmware/boot interfaces
vary a great deal, so on these systems the Linux kernel has to take
care of many system-specific low-level issues which would be handled
by the mainboard's BIOS in the PC world.
</para>

<para arch="armel;armhf">
At the beginning of the ARM support in the Linux kernel, the hardware
variety resulted in the requirement of having a separate kernel for
each ARM system in contrast to the <quote>one-fits-all</quote> kernel
for PC systems.  As this approach does not scale to a large number of
different systems, work was done to allow booting with a single ARM
kernel that can run on different ARM systems.  Support for newer ARM
systems is now implemented in a way that allows the use of such a
multiplatform kernel, but for several older systems a separate
specific kernel is still required. Because of this, the standard
&debian; distribution only supports installation on a selected number
of such older ARM systems, alongside the newer systems which are
supported by the ARM multiplatform kernels (called <quote>armmp</quote>) in
&debian;/armhf.
</para>

<para arch="arm64">
The ARM architecture is used mainly in so-called
<quote>system-on-chip</quote> (SoC) designs. These SoCs are designed
by many different companies, often with vastly varying hardware
components even for the very basic functionality required to bring the
system up. Older versions of the ARM architecture have seen massive
differences from one SoC to the next, but ARMv8 (arm64) is much more
standardised and so is easier for the Linux kernel and other software
to support.
</para>

<para arch="arm64">
Server versions of ARMv8 hardware are typically configured using the
Unified Extensible Firmware Interface (UEFI) and Advanced
Configuration and Power Interface (ACPI) standards. These two provide
common, device-independent ways to boot and configure computer
hardware. They are also common in the x86 PC world.
</para>

  </sect2>

<sect2 arch="arm64" id="arm64-supported-platforms"><title>Platforms supported by Debian/arm64</title>

  <para>
    Arm64/AArch64/ARMv8 hardware became available quite late in the
    &debian; &releasename-cap; release cycle so not many platforms had
    support merged in the mainline kernel version by the time of this
    release; this is the main requirement to have &d-i; working on
    them. The following platforms are known to be supported by
    &debian;/arm64 in this release. There is only one kernel image,
    which supports all the listed platforms.
  </para>

  <variablelist>
      <varlistentry>
        <term>Applied Micro (APM) Mustang/X-Gene</term>
        <listitem>
          <para>
	    The APM Mustang was the first Linux-capable ARMv8 system
	    available. It uses the X-gene SoC, which has since also
	    been used in other machines. It is an 8-core CPU, with
	    ethernet, USB and serial. A common form-factor looks just
	    like a desktop PC box, but many other versions are
	    expected in the future. Most of the hardware is supported
	    in the mainline kernel, but at this point USB support is
	    lacking in the &releasename-cap; kernel.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>ARM Juno Development Platform</term>
        <listitem>
          <para>	    
	    Juno is a capable development board with a 6-core (2xA57,
	    4xA53) ARMv8-A 800Mhz CPU, Mali (T624) graphics, 8GB DDR3
	    RAM, Ethernet, USB, Serial. It was designed for system
	    bring-up and power testing so is neither small nor cheap,
	    but was one of the first boards available. All the
	    on-board hardware is supported in the mainline kernel and
	    in &releasename-cap;.
          </para>
        </listitem>
      </varlistentry>

  </variablelist>

  <para>
    When using &d-i; on non-UEFI systems, you may have to manually
    make the system bootable at the end of the installation, e.g. by
    running the required commands in a shell started from within
    &d-i;. flash-kernel knows how to set up an X-Gene system booting
    with U-Boot.
  </para>

  <sect3 arch="arm64" id="arm64-other-platforms"><title>Other platforms</title>
  <para>
    The multiplatform support in the arm64 Linux kernel may also allow
    running &d-i; on arm64 systems not explicitly listed above. So
    long as the kernel used by &d-i; has support for the target
    system's components, and a device-tree file for that target is
    available, a new target system may work just fine.  In these
    cases, the installer can usually provide a working installation,
    and so long as UEFI is in use, it should be able to make the
    system bootable as well. If UEFI is not used you may also need to
    perform some manual configuration steps to make the system
    bootable.
  </para>
  </sect3>
</sect2>


<sect2 arch="armhf" id="armhf-armmp-supported-platforms"><title>Platforms supported by Debian/armhf</title>

  <para>
  The following systems are known to work with &debian;/armhf using the
  multiplatform (armmp) kernel:

  <variablelist>

      <varlistentry>
        <term>Freescale MX53 Quick Start Board</term>
        <listitem>
          <para>   
            The IMX53QSB is a development board based on the i.MX53 SoC.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>Versatile Express</term>
        <listitem>
          <para>   
            The Versatile Express is a development board series from ARM
            consisting of a baseboard which can be equipped with various CPU
            daughter boards.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>Certain Allwinner sunXi-based development boards and embedded
        systems</term>
        <listitem>
          <para>   
            The armmp kernel supports several development boards and
            embedded systems based on the Allwinner A10 (architecture
            codename <quote>sun4i</quote>), A10s/A13 (architecture codename
            <quote>sun5i</quote>) and A20 (architecture codename
            <quote>sun7i</quote>) SoCs.  Full installer support is currently
            available for the following sunXi-based systems:
            <itemizedlist>
             <listitem><para>
               Cubietech Cubieboard 1 + 2 / Cubietruck
             </para></listitem>
             <listitem><para>
               LeMaker Banana Pi and Banana Pro
             </para></listitem>
             <listitem><para>
               LinkSprite pcDuino and pcDuino3
             </para></listitem>
             <listitem><para>
               Mele A1000
             </para></listitem>
             <listitem><para>
               Miniand Hackberry
             </para></listitem>
             <listitem><para>
               Olimex A10-Olinuxino-LIME / A10s-Olinuxino Micro /
               A13-Olinuxino / A13-Olinuxino Micro / 
               A20-Olinuxino-LIME / A20-Olinuxino-LIME2 / A20-Olinuxino Micro           
             </para></listitem>
             <listitem><para>
               PineRiver Mini X-Plus
             </para></listitem>

            </itemizedlist>  
          </para> 
          <para>
            System support for Allwinner sunXi-based devices is limited to
            drivers and device-tree information available in the mainline
            Linux kernel.  The android-derived linux-sunxi.org 3.4 kernel
            series is not supported by &debian;.
          </para> 
          <para>
            The mainline Linux kernel generally supports serial console,
            ethernet, SATA, USB and MMC/SD-cards on Allwinner A10, A10s/A13
            and A20 SoCs, but it does not have native drivers for the
            display (HDMI/VGA/LCD) and audio hardware in these SoCs.  The
            NAND flash memory that is built into some sunXi-based systems is
            not supported.
          </para>
          <para>
            Using a local display is technically possible without native
            display drivers via the <quote>simplefb</quote> infrastructure
            in the mainline kernel, which relies on the
            <quote>U-Boot</quote> bootloader for initialising the display
            hardware, but this is not supported by the U-Boot version in
            &debian; 8.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>SolidRun Cubox-i2eX / Cubox-i4Pro</term>
        <listitem>
          <para>
            The Cubox-i series is a set of small, cubical-shaped systems
            based on the Freescale i.MX6 SoC family.  System support for
            the Cubox-i series is limited to drivers and device-tree
            information available in the mainline Linux kernel; the
            Freescale 3.0 kernel series for the Cubox-i is not supported by
            &debian;.  Available drivers in the mainline kernel include
            serial console, ethernet, USB, MMC/SD-card and display
            support over HDMI (console and X11). In addition to that,
            the eSATA port on the Cubox-i4Pro is supported.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>Wandboard Quad</term>
        <listitem>
          <para>
            The Wandboard Quad is a development board based on the Freescale
            i.MX6 Quad SoC.  System support for it is limited to drivers and
            device-tree information available in the mainline Linux kernel;
            the wandboard-specific 3.0 and 3.10 kernel series from
            wandboard.org are not supported by &debian;.  The mainline kernel
            includes driver support for serial console, display via HDMI
            (console and X11), ethernet, USB, MMC/SD and SATA.  Support for
            the onboard audio options (analog, S/PDIF, HDMI-Audio) and for
            the onboard WLAN/Bluetooth module is not available in &debian;
            8.
          </para>
        </listitem>
      </varlistentry>

    </variablelist>
  </para>

  <para>
    
    Generally, the ARM multiplatform support in the Linux kernel
    allows running &d-i; on armhf systems not explicitly listed above,
    as long as the kernel used by &d-i; has support for the target
    system's components and a device-tree file for the target is
    available.  In these cases, the installer can usually provide a
    working installation, but it may not be able to automatically make
    the system bootable. Doing that in many cases requires
    device-specific information.
   
  </para>
  <para>
    When using &d-i; on such systems, you may have to manually make
    the system bootable at the end of the installation, e.g. by
    running the required commands in a shell started from within
    &d-i;.
  </para>

</sect2>

<sect2 arch="armhf" id="armhf-unsupported-platforms"><title>Platforms no longer supported by Debian/armhf</title>

<variablelist>
<varlistentry>
<term>EfikaMX</term>
<listitem><para>

The EfikaMX platform (Genesi Efika Smartbook and Genesi EfikaMX
nettop) was supported in &debian; 7 with a platform-specific kernel,
but is no longer supported from &debian; 8 onwards.  The code required
to build the formerly used platform-specific kernel has been removed
from the upstream Linux kernel source in 2012, so &debian; cannot
provide newer builds. Using the armmp multiplatform kernel on the
EfikaMX platform would require device-tree support for it, which is
currently not available.

</para></listitem>
</varlistentry>
</variablelist>

</sect2>


<sect2 arch="armel" id="armel-supported-platforms"><title>Platforms supported by Debian/armel</title>

<para>

The following platforms are supported by &debian;/armel; they require
platform-specific kernels.

<variablelist>

<varlistentry>
<term>IXP4xx</term>
<listitem><para>   

The Intel IXP4xx processor series is used in commonly used network
attached storage (NAS) devices like the Linksys NSLU2.

</para><para>

While there is kernel support for this platform in &debian; 8, it is
not supported by the &d-i;.  It is possible to do a
<quote>dist-upgrade</quote> from &debian; 7 to &debian; 8 for existing
installations, though.  Due to the small amount of RAM that systems
based on the IXP4xx typically have, this requires that swap space is
enabled prior to upgrading. Support for the IXP4xx platform will be
dropped completely in &debian; 9.

</para></listitem>
</varlistentry>   

<varlistentry>
<term>Kirkwood</term>
<listitem><para>

Kirkwood is a system-on-chip (SoC) from Marvell that integrates an ARM
CPU, Ethernet, SATA, USB, and other functionality in one chip.
&debian; currently supports the following Kirkwood based devices:
OpenRD (OpenRD-Base, OpenRD-Client and OpenRD-Ultimate), <ulink
url="&url-arm-cyrius-sheevaplug;">plug computers (SheevaPlug, GuruPlug
and DreamPlug)</ulink>, <ulink
url="&url-arm-cyrius-qnap-kirkwood;">QNAP Turbo Station</ulink> (all
TS-11x, TS-21x and TS-41x models), and LaCie NASes (Network Space v2,
Network Space Max v2, Internet Space v2, d2 Network v2, 2Big Network
v2 and 5Big Network v2).

</para></listitem>
</varlistentry>

<varlistentry>
<term>Orion5x</term>
<listitem><para>

Orion is a system-on-chip (SoC) from Marvell that integrates an ARM
CPU, Ethernet, SATA, USB, and other functionality in one chip. There
are many Network Attached Storage (NAS) devices on the market that are
based on an Orion chip. &debian; currently supports the following
Orion based devices: <ulink url="&url-arm-cyrius-kuroboxpro;">Buffalo
Kurobox</ulink> and <ulink url="&url-arm-cyrius-mv2120;">HP
mv2120</ulink>.

</para></listitem>
</varlistentry>

<varlistentry>
<term>Versatile</term>
<listitem><para>

The Versatile platform is emulated by QEMU and is therefore a nice way
to test and run &debian; on ARM if you don't have real hardware.

</para></listitem>
</varlistentry>

</variablelist>

</para>
</sect2>