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+The Gianfar Ethernet Driver
+Sysfs File description
+Author: Andy Fleming <afleming@freescale.com>
+Updated: 2005-07-28
+Several of the features of the gianfar driver are controlled
+through sysfs files. These are:
+To stash RX Buffer Descriptors in the L2, echo 'on' or '1' to
+bd_stash, echo 'off' or '0' to disable
+To stash the first n bytes of the packet in L2, echo the number
+of bytes to buf_stash_len. echo 0 to disable.
+WARNING: You could really screw these up if you set them too low or high!
+To change the number of bytes the controller needs in the
+fifo before it starts transmission, echo the number of bytes to
+fifo_thresh. Range should be 0-511.
+When the FIFO has less than this many bytes during a transmit, it
+enters starve mode, and increases the priority of TX memory
+transactions. To change, echo the number of bytes to
+fifo_starve. Range should be 0-511.
+Once in starve mode, the FIFO remains there until it has this
+many bytes. To change, echo the number of bytes to
+fifo_starve_off. Range should be 0-511.
+The eTSEC controller (first included in parts from late 2005 like
+the 8548) has the ability to perform TCP, UDP, and IP checksums
+in hardware. The Linux kernel only offloads the TCP and UDP
+checksums (and always performs the pseudo header checksums), so
+the driver only supports checksumming for TCP/IP and UDP/IP
+packets. Use ethtool to enable or disable this feature for RX
+and TX.
+In order to use VLAN, please consult Linux documentation on
+configuring VLANs. The gianfar driver supports hardware insertion and
+extraction of VLAN headers, but not filtering. Filtering will be
+done by the kernel.
+The gianfar driver supports using the group hash table on the
+TSEC (and the extended hash table on the eTSEC) for multicast
+filtering. On the eTSEC, the exact-match MAC registers are used
+before the hash tables. See Linux documentation on how to join
+multicast groups.
+The gianfar driver supports padding received frames with 2 bytes
+to align the IP header to a 16-byte boundary, when supported by
+The gianfar driver supports the use of ethtool for many
+configuration options. You must run ethtool only on currently
+open interfaces. See ethtool documentation for details.