SYSFS FILES
  
    For each InfiniBand device, the InfiniBand drivers create the
    following files under /sys/class/infiniband/<device name>:
  
      node_type      - Node type (CA, switch or router)
      node_guid      - Node GUID
      sys_image_guid - System image GUID
  
    In addition, there is a "ports" subdirectory, with one subdirectory
    for each port.  For example, if mthca0 is a 2-port HCA, there will
    be two directories:
  
      /sys/class/infiniband/mthca0/ports/1
      /sys/class/infiniband/mthca0/ports/2
  
    (A switch will only have a single "0" subdirectory for switch port
    0; no subdirectory is created for normal switch ports)
  
    In each port subdirectory, the following files are created:
  
      cap_mask       - Port capability mask
      lid            - Port LID
      lid_mask_count - Port LID mask count
      rate           - Port data rate (active width * active speed)
      sm_lid         - Subnet manager LID for port's subnet
      sm_sl          - Subnet manager SL for port's subnet
      state          - Port state (DOWN, INIT, ARMED, ACTIVE or ACTIVE_DEFER)
      phys_state     - Port physical state (Sleep, Polling, LinkUp, etc)
  
    There is also a "counters" subdirectory, with files
  
      VL15_dropped
      excessive_buffer_overrun_errors
      link_downed
      link_error_recovery
      local_link_integrity_errors
      port_rcv_constraint_errors
      port_rcv_data
      port_rcv_errors
      port_rcv_packets
      port_rcv_remote_physical_errors
      port_rcv_switch_relay_errors
      port_xmit_constraint_errors
      port_xmit_data
      port_xmit_discards
      port_xmit_packets
      symbol_error
  
    Each of these files contains the corresponding value from the port's
    Performance Management PortCounters attribute, as described in
    section 16.1.3.5 of the InfiniBand Architecture Specification.
  
    The "pkeys" and "gids" subdirectories contain one file for each
    entry in the port's P_Key or GID table respectively.  For example,
    ports/1/pkeys/10 contains the value at index 10 in port 1's P_Key
    table.
  
  MTHCA
  
    The Mellanox HCA driver also creates the files:
  
      hw_rev   - Hardware revision number
      fw_ver   - Firmware version
      hca_type - HCA type: "MT23108", "MT25208 (MT23108 compat mode)",
                 or "MT25208"