gianfar.txt 2.3 KB

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  1. The Gianfar Ethernet Driver
  2. Sysfs File description
  3. Author: Andy Fleming <afleming@freescale.com>
  4. Updated: 2005-07-28
  5. SYSFS
  6. Several of the features of the gianfar driver are controlled
  7. through sysfs files. These are:
  8. bd_stash:
  9. To stash RX Buffer Descriptors in the L2, echo 'on' or '1' to
  10. bd_stash, echo 'off' or '0' to disable
  11. rx_stash_len:
  12. To stash the first n bytes of the packet in L2, echo the number
  13. of bytes to buf_stash_len. echo 0 to disable.
  14. WARNING: You could really screw these up if you set them too low or high!
  15. fifo_threshold:
  16. To change the number of bytes the controller needs in the
  17. fifo before it starts transmission, echo the number of bytes to
  18. fifo_thresh. Range should be 0-511.
  19. fifo_starve:
  20. When the FIFO has less than this many bytes during a transmit, it
  21. enters starve mode, and increases the priority of TX memory
  22. transactions. To change, echo the number of bytes to
  23. fifo_starve. Range should be 0-511.
  24. fifo_starve_off:
  25. Once in starve mode, the FIFO remains there until it has this
  26. many bytes. To change, echo the number of bytes to
  27. fifo_starve_off. Range should be 0-511.
  28. CHECKSUM OFFLOADING
  29. The eTSEC controller (first included in parts from late 2005 like
  30. the 8548) has the ability to perform TCP, UDP, and IP checksums
  31. in hardware. The Linux kernel only offloads the TCP and UDP
  32. checksums (and always performs the pseudo header checksums), so
  33. the driver only supports checksumming for TCP/IP and UDP/IP
  34. packets. Use ethtool to enable or disable this feature for RX
  35. and TX.
  36. VLAN
  37. In order to use VLAN, please consult Linux documentation on
  38. configuring VLANs. The gianfar driver supports hardware insertion and
  39. extraction of VLAN headers, but not filtering. Filtering will be
  40. done by the kernel.
  41. MULTICASTING
  42. The gianfar driver supports using the group hash table on the
  43. TSEC (and the extended hash table on the eTSEC) for multicast
  44. filtering. On the eTSEC, the exact-match MAC registers are used
  45. before the hash tables. See Linux documentation on how to join
  46. multicast groups.
  47. PADDING
  48. The gianfar driver supports padding received frames with 2 bytes
  49. to align the IP header to a 16-byte boundary, when supported by
  50. hardware.
  51. ETHTOOL
  52. The gianfar driver supports the use of ethtool for many
  53. configuration options. You must run ethtool only on currently
  54. open interfaces. See ethtool documentation for details.