1. 08 Oct, 2008 1 commit
    • 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