• Vladimir Oltean's avatar
    net: dsa: ocelot: add tagger for Ocelot/Felix switches · 8dce89aa
    Vladimir Oltean authored
    While it is entirely possible that this tagger format is in fact more
    generic than just these 2 switch families, I don't have that knowledge.
    The Seville switch in NXP T1040 has a similar frame format, but there
    are enough differences (e.g. DEST field starts at bit 57 instead of 56)
    that calling this file tag_vitesse.c is a bit of a stretch at the
    moment. The frame format has been listed in a comment so that people who
    add support for further Vitesse switches can rework this tagger while
    keeping compatibility with Felix.
    
    The "ocelot" name was chosen instead of "felix" because even the Ocelot
    switch can act as a DSA device when it is used in NPI mode, and the Felix
    tagger format is almost identical. Currently it is only used for the
    Felix switch embedded in the NXP LS1028A chip.
    
    The ABI for this tagger should be considered "not stable" at the moment.
    The DSA tag is always placed before the Ethernet header and therefore,
    we are using the long prefix for RX tags to avoid putting the DSA master
    port in promiscuous mode. Once there will be an API in DSA for drivers
    to request DSA masters to be in promiscuous mode unconditionally, we
    will switch to the "no prefix" extraction frame header, which will save
    16 padding bytes for each RX frame.
    Signed-off-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
    Reviewed-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    8dce89aa
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