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1 | The Gianfar Ethernet Driver |
2 | Sysfs File description | |
3 | ||
4 | Author: Andy Fleming <afleming@freescale.com> | |
5 | Updated: 2005-07-28 | |
6 | ||
7 | SYSFS | |
8 | ||
9 | Several of the features of the gianfar driver are controlled | |
10 | through sysfs files. These are: | |
11 | ||
12 | bd_stash: | |
13 | To stash RX Buffer Descriptors in the L2, echo 'on' or '1' to | |
14 | bd_stash, echo 'off' or '0' to disable | |
15 | ||
16 | rx_stash_len: | |
17 | To stash the first n bytes of the packet in L2, echo the number | |
18 | of bytes to buf_stash_len. echo 0 to disable. | |
19 | ||
20 | WARNING: You could really screw these up if you set them too low or high! | |
21 | fifo_threshold: | |
22 | To change the number of bytes the controller needs in the | |
23 | fifo before it starts transmission, echo the number of bytes to | |
24 | fifo_thresh. Range should be 0-511. | |
25 | ||
26 | fifo_starve: | |
27 | When the FIFO has less than this many bytes during a transmit, it | |
28 | enters starve mode, and increases the priority of TX memory | |
29 | transactions. To change, echo the number of bytes to | |
30 | fifo_starve. Range should be 0-511. | |
31 | ||
32 | fifo_starve_off: | |
33 | Once in starve mode, the FIFO remains there until it has this | |
34 | many bytes. To change, echo the number of bytes to | |
35 | fifo_starve_off. Range should be 0-511. | |
36 | ||
37 | CHECKSUM OFFLOADING | |
38 | ||
39 | The eTSEC controller (first included in parts from late 2005 like | |
40 | the 8548) has the ability to perform TCP, UDP, and IP checksums | |
41 | in hardware. The Linux kernel only offloads the TCP and UDP | |
42 | checksums (and always performs the pseudo header checksums), so | |
43 | the driver only supports checksumming for TCP/IP and UDP/IP | |
44 | packets. Use ethtool to enable or disable this feature for RX | |
45 | and TX. | |
46 | ||
47 | VLAN | |
48 | ||
49 | In order to use VLAN, please consult Linux documentation on | |
50 | configuring VLANs. The gianfar driver supports hardware insertion and | |
51 | extraction of VLAN headers, but not filtering. Filtering will be | |
52 | done by the kernel. | |
53 | ||
54 | MULTICASTING | |
55 | ||
56 | The gianfar driver supports using the group hash table on the | |
57 | TSEC (and the extended hash table on the eTSEC) for multicast | |
58 | filtering. On the eTSEC, the exact-match MAC registers are used | |
59 | before the hash tables. See Linux documentation on how to join | |
60 | multicast groups. | |
61 | ||
62 | PADDING | |
63 | ||
64 | The gianfar driver supports padding received frames with 2 bytes | |
65 | to align the IP header to a 16-byte boundary, when supported by | |
66 | hardware. | |
67 | ||
68 | ETHTOOL | |
69 | ||
70 | The gianfar driver supports the use of ethtool for many | |
71 | configuration options. You must run ethtool only on currently | |
72 | open interfaces. See ethtool documentation for details. |