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  • Andrew Lunn's avatar
    dsa: mv88e6xxx: Zodiac Spanning Tree Safety Net. · f22f9583
    Andrew Lunn authored and Ezequiel Garcia's avatar Ezequiel Garcia committed
    Provides a mechanism to protect the CPU from broadcast storm when
    spanning tree does the wrong thing/is too slow.
    
    /sys/kernel/debugfs/zii_hacks contains a directory per switch chip.
    Within each directory are two files per user port:
    
    /sys/kernel/debug/zii_hacks/0.1:00# ls
    link_shutdown_1
    link_shutdown_2
    link_shutdown_3
    link_shutdown_4
    shutdown_link_on_member_violation_1
    shutdown_link_on_member_violation_2
    shutdown_link_on_member_violation_3
    shutdown_link_on_member_violation_4
    
    echo'ing y into shutdown_link_on_member_violation_? enables the
    feature for that port. echo'ing n disables it. If an ATU member
    violation interrupt occurs for a port which is enabled, the port is
    disabled. For a port using a copper PHY, the PHY transmitter is
    disabled. This can only be restored with a cold boot, or maybe a
    hardware reset of the switch. Software reset is not sufficient. If the
    port is using an SERDES, e.g for an SFF/SFP, the SERDES is powered
    off. ifdown/ifup is probably sufficient to clear this.
    
    link_shutdown-? will indicate if a port has sometime in the past been
    disabled because of an ATU member violation. For a SERDES port, an
    ifdown/up will restore the operation of the port, and the contents of
    the file will reflect this.
    f22f9583