• Lennert Buytenhek's avatar
    net: Distributed Switch Architecture protocol support · 91da11f8
    Lennert Buytenhek authored
    Distributed Switch Architecture is a protocol for managing hardware
    switch chips.  It consists of a set of MII management registers and
    commands to configure the switch, and an ethernet header format to
    signal which of the ports of the switch a packet was received from
    or is intended to be sent to.
    
    The switches that this driver supports are typically embedded in
    access points and routers, and a typical setup with a DSA switch
    looks something like this:
    
    	+-----------+       +-----------+
    	|           | RGMII |           |
    	|           +-------+           +------ 1000baseT MDI ("WAN")
    	|           |       |  6-port   +------ 1000baseT MDI ("LAN1")
    	|    CPU    |       |  ethernet +------ 1000baseT MDI ("LAN2")
    	|           |MIImgmt|  switch   +------ 1000baseT MDI ("LAN3")
    	|           +-------+  w/5 PHYs +------ 1000baseT MDI ("LAN4")
    	|           |       |           |
    	+-----------+       +-----------+
    
    The switch driver presents each port on the switch as a separate
    network interface to Linux, polls the switch to maintain software
    link state of those ports, forwards MII management interface
    accesses to those network interfaces (e.g. as done by ethtool) to
    the switch, and exposes the switch's hardware statistics counters
    via the appropriate Linux kernel interfaces.
    
    This initial patch supports the MII management interface register
    layout of the Marvell 88E6123, 88E6161 and 88E6165 switch chips, and
    supports the "Ethertype DSA" packet tagging format.
    
    (There is no officially registered ethertype for the Ethertype DSA
    packet format, so we just grab a random one.  The ethertype to use
    is programmed into the switch, and the switch driver uses the value
    of ETH_P_EDSA for this, so this define can be changed at any time in
    the future if the one we chose is allocated to another protocol or
    if Ethertype DSA gets its own officially registered ethertype, and
    everything will continue to work.)
    Signed-off-by: default avatarLennert Buytenhek <buytenh@marvell.com>
    Tested-by: default avatarNicolas Pitre <nico@marvell.com>
    Tested-by: default avatarByron Bradley <byron.bbradley@gmail.com>
    Tested-by: default avatarTim Ellis <tim.ellis@mac.com>
    Tested-by: default avatarPeter van Valderen <linux@ddcrew.com>
    Tested-by: default avatarDirk Teurlings <dirk@upexia.nl>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    91da11f8
if_ether.h 5.74 KB