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  • Adding support for new hardware
    ===============================
    This page will give a short overview on how to add support
    for new hardware to Gluon.
    
    Hardware requirements
    ---------------------
    Having an ath9k (or ath10k) based WLAN adapter is highly recommended,
    although other chipsets may also work. VAP (multiple SSID) support
    
    .. _hardware-adding-profiles:
    
    Adding profiles
    ---------------
    
    The vast majority of devices with ath9k WLAN is based on the ar71xx target of OpenWrt.
    
    If the hardware you want to add support for is ar71xx, adding a new profile
    is sufficient.
    
    Profiles are defined in ``targets/*`` in a shell-based DSL (so common shell
    
    command syntax like ``if`` can be used).
    
    The ``device`` command is used to define an image build for a device. It takes
    two or three parameters.
    
    The first parameter defines the Gluon profile name, which is used to refer to the
    device and is part of the generated image name. The profile name must be same as
    the output of the following command (on the target device), so the autoupdater
    can work::
    
        lua -e 'print(require("platform_info").get_image_name())'
    
    While porting Gluon to a new device, it might happen that the profile name is
    unknown. Best practise is to generate an image first by using an arbitrary value
    
    and then executing the lua command on the device and use its output from then on.
    
    
    The second parameter defines the name of the image files generated by OpenWrt. Usually,
    it is also the OpenWrt profile name; for devices that still use the old image build
    code, a third parameter with the OpenWrt profile name can be passed. The profile names
    
    can be found in the image Makefiles in ``openwrt/target/linux/<target>/image/Makefile``.
    
    Examples::
    
        device tp-link-tl-wr1043n-nd-v1 tl-wr1043nd-v1
        device alfa-network-hornet-ub hornet-ub HORNETUB
    
    Suffixes and extensions
    '''''''''''''''''''''''
    
    By default, image files are expected to have the extension ``.bin``. In addition,
    
    the images generated by OpenWrt have a suffix before the extension that defaults to
    
    ``-squashfs-factory`` and ``-squashfs-sysupgrade``.
    
    This can be changed using the ``factory`` and ``sysupgrade`` commands, either at
    the top of the file to set the defaults for all images, or for a single image. There
    are three forms with 0 to 2 arguments (all work with ``sysupgrade`` as well)::
    
        factory SUFFIX .EXT
        factory .EXT
        factory
    
    When only an extension is given, the default suffix is retained. When no arguments
    are given, this signals that no factory (or sysupgrade) image exists.
    
    Aliases
    '''''''
    
    
    Sometimes multiple models use the same OpenWrt images. In this case, the ``alias``
    
    command can be used to create symlinks and additional entries in the autoupdater
    manifest for the alternative models.
    
    Standalone images
    '''''''''''''''''
    
    
    On targets without *per-device rootfs* support in OpenWrt, the commands described above
    
    can't be used. Instead, ``factory_image`` and ``sysupgrade_image`` are used::
    
        factory_image PROFILE IMAGE .EXT
        sysupgrade_image PROFILE IMAGE .EXT
    
    Again, the profile name must match the value printed by the aforementioned Lua
    command. The image name must match the part between the target name and the extension
    
    as generated by OpenWrt and is to be omitted when no such part exists.
    
    
    Packages
    ''''''''
    
    The ``packages`` command takes an arbitrary number of arguments. Each argument
    defines an additional package to include in the images in addition to the default
    
    package sets defined by OpenWrt. When a package name is prefixed by a minus sign, the
    
    packages are excluded instead.
    
    The ``packages`` command may be used at the top of a target definition to modify
    the default package list for all images, or just for a single device (when the
    target supports *per-default rootfs*).
    
    
    Configuration
    '''''''''''''
    
    
    The ``config`` command allows to add arbitrary target-specific OpenWrt configuration
    
    to be emitted to ``.config``.
    
    Notes
    '''''
    
    
    On devices with multiple WLAN adapters, care must also be taken that the primary MAC address is
    configured correctly. ``/lib/gluon/core/sysconfig/primary_mac`` should contain the MAC address which
    
    can be found on a label on most hardware; if it does not, ``/lib/gluon/upgrade/010-primary-mac``
    
    in ``gluon-core`` might need a fix. (There have also been cases in which the address was incorrect
    
    even on devices with only one WLAN adapter, in these cases a OpenWrt bug was the cause).
    
    
    Adding support for new hardware targets
    ---------------------------------------
    
    Adding a new target is much more complex than adding a new profile. There are two basic steps
    required for adding a new target:
    
    
    Package adjustments
    '''''''''''''''''''
    
    
    One package that may need adjustments for new targets is ``libplatforminfo`` (to be found in
    
    Lustikus's avatar
    Lustikus committed
    `packages/gluon/libs/libplatforminfo <https://github.com/freifunk-gluon/packages/tree/master/libs/libplatforminfo>`_).
    
    If the new platform works fine with the definitions found in ``default.c``, nothing needs to be done. Otherwise,
    create a definition for the added target or subtarget, either by symlinking one of the files in the ``templates``
    directory, or adding a new source file.
    
    On many targets, Gluon's network setup scripts (mainly in the package ``gluon-core``)
    
    won't run correctly without some adjustments, so better double check that everything is fine there (and the files
    ``primary_mac``, ``lan_ifname`` and ``wan_ifname`` in ``/lib/gluon/core/sysconfig/`` contain sensible values).
    
    
    Build system support
    ''''''''''''''''''''
    
    A definition for the new target must be created under ``targets``, and it must be added
    to ``targets/targets.mk``. The ``GluonTarget`` macro takes one to three arguments:
    the target name, the Gluon subtarget name (if the target has subtargets), and the
    
    OpenWrt subtarget name (if it differs from the Gluon subtarget). The third argument
    
    can be used to define multiple Gluon targets with different configuration for the
    
    same OpenWrt target, like it is done for the ``ar71xx-tiny`` target.
    
    After this, is should be sufficient to call ``make GLUON_TARGET=<target>`` to build the images for the new target.