RapidIO sysfs Files
  
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  
  1. Device Subdirectories
  ------------------------
  
  For each RapidIO device, the RapidIO subsystem creates files in an individual
  subdirectory with the following name, /sys/bus/rapidio/devices/<device_name>.
  
  The format of device_name is "nn:d:iiii", where:
  
  nn - two-digit hexadecimal ID of RapidIO network where the device resides
  d  - device typr: 'e' - for endpoint or 's' - for switch
  iiii - four-digit device destID for endpoints, or switchID for switches
  
  For example, below is a list of device directories that represents a typical
  RapidIO network with one switch, one host, and two agent endpoints, as it is
  seen by the enumerating host (destID = 1):
  
  /sys/bus/rapidio/devices/00:e:0000
  /sys/bus/rapidio/devices/00:e:0002
  /sys/bus/rapidio/devices/00:s:0001
  
  NOTE: An enumerating or discovering endpoint does not create a sysfs entry for
  itself, this is why an endpoint with destID=1 is not shown in the list.
  
  2. Attributes Common for All Devices
  ------------------------------------
  
  Each device subdirectory contains the following informational read-only files:
  
         did - returns the device identifier
         vid - returns the device vendor identifier
  device_rev - returns the device revision level
     asm_did - returns identifier for the assembly containing the device
     asm_rev - returns revision level of the assembly containing the device
     asm_vid - returns vendor identifier of the assembly containing the device
     destid  - returns device destination ID assigned by the enumeration routine
               (see 4.1 for switch specific details)
     lprev   - returns name of previous device (switch) on the path to the device
               that that owns this attribute
  
  In addition to the files listed above, each device has a binary attribute file
  that allows read/write access to the device configuration registers using
  the RapidIO maintenance transactions:
  
   config - reads from and writes to the device configuration registers.
  
  This attribute is similar in behavior to the "config" attribute of PCI devices
  and provides an access to the RapidIO device registers using standard file read
  and write operations.
  
  3. Endpoint Device Attributes
  -----------------------------
  
  Currently Linux RapidIO subsystem does not create any endpoint specific sysfs
  attributes. It is possible that RapidIO master port drivers and endpoint device
  drivers will add their device-specific sysfs attributes but such attributes are
  outside the scope of this document.
  
  4. Switch Device Attributes
  ---------------------------
  
  RapidIO switches have additional attributes in sysfs. RapidIO subsystem supports
  common and device-specific sysfs attributes for switches. Because switches are
  integrated into the RapidIO subsystem, it offers a method to create
  device-specific sysfs attributes by specifying a callback function that may be
  set by the switch initialization routine during enumeration or discovery process.
  
  4.1 Common Switch Attributes
  
     routes - reports switch routing information in "destID port" format. This
              attribute reports only valid routing table entries, one line for
              each entry.
     destid - device destination ID that defines a route to the switch
   hopcount - number of hops on the path to the switch
      lnext - returns names of devices linked to the switch except one of a device
              linked to the ingress port (reported as "lprev"). This is an array
              names with number of lines equal to number of ports in switch. If
              a switch port has no attached device, returns "null" instead of
              a device name.
  
  4.2 Device-specific Switch Attributes
  
  Device-specific switch attributes are listed for each RapidIO switch driver
  that exports additional attributes.
  
  IDT_GEN2:
   errlog - reads contents of device error log until it is empty.