projects / mirror_ubuntu-artful-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | /* nicstar.c v0.22 Jawaid Bazyar (bazyar@hypermall.com) |
| 2 | * nicstar.c, M. Welsh (matt.welsh@cl.cam.ac.uk) | |
| 3 | * | |
| 4 | * Hacked October, 1997 by Jawaid Bazyar, Interlink Advertising Services Inc. | |
| 5 | * http://www.hypermall.com/ | |
| 6 | * 10/1/97 - commented out CFG_PHYIE bit - we don't care when the PHY | |
| 7 | * interrupts us (except possibly for removal/insertion of the cable?) | |
| 8 | * 10/4/97 - began heavy inline documentation of the code. Corrected typos | |
| 9 | * and spelling mistakes. | |
| 10 | * 10/5/97 - added code to handle PHY interrupts, disable PHY on | |
| 11 | * loss of link, and correctly re-enable PHY when link is | |
| 12 | * re-established. (put back CFG_PHYIE) | |
| 13 | * | |
| 14 | * Modified to work with the IDT7721 nicstar -- AAL5 (tested) only. | |
| 15 | * | |
| 7ff6e6f7 | 16 | * R. D. Rechenmacher <ron@fnal.gov>, Aug. 6, 1997 |
| 1da177e4 LT |
17 | * |
| 18 | * Linux driver for the IDT77201 NICStAR PCI ATM controller. | |
| 19 | * PHY component is expected to be 155 Mbps S/UNI-Lite or IDT 77155; | |
| 20 | * see init_nicstar() for PHY initialization to change this. This driver | |
| 21 | * expects the Linux ATM stack to support scatter-gather lists | |
| 22 | * (skb->atm.iovcnt != 0) for Rx skb's passed to vcc->push. | |
| 23 | * | |
| 24 | * Implementing minimal-copy of received data: | |
| 25 | * IDT always receives data into a small buffer, then large buffers | |
| 26 | * as needed. This means that data must always be copied to create | |
| 27 | * the linear buffer needed by most non-ATM protocol stacks (e.g. IP) | |
| 28 | * Fix is simple: make large buffers large enough to hold entire | |
| 29 | * SDU, and leave <small_buffer_data> bytes empty at the start. Then | |
| 30 | * copy small buffer contents to head of large buffer. | |
| 31 | * Trick is to avoid fragmenting Linux, due to need for a lot of large | |
| 32 | * buffers. This is done by 2 things: | |
| 33 | * 1) skb->destructor / skb->atm.recycle_buffer | |
| 34 | * combined, allow nicstar_free_rx_skb to be called to | |
| 35 | * recycle large data buffers | |
| 36 | * 2) skb_clone of received buffers | |
| 37 | * See nicstar_free_rx_skb and linearize_buffer for implementation | |
| 38 | * details. | |
| 39 | * | |
| 40 | * | |
| 41 | * | |
| 42 | * Copyright (c) 1996 University of Cambridge Computer Laboratory | |
| 43 | * | |
| 44 | * This program is free software; you can redistribute it and/or modify | |
| 45 | * it under the terms of the GNU General Public License as published by | |
| 46 | * the Free Software Foundation; either version 2 of the License, or | |
| 47 | * (at your option) any later version. | |
| 48 | * | |
| 49 | * This program is distributed in the hope that it will be useful, | |
| 50 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 51 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 52 | * GNU General Public License for more details. | |
| 53 | * | |
| 54 | * You should have received a copy of the GNU General Public License | |
| 55 | * along with this program; if not, write to the Free Software | |
| 56 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
| 57 | * | |
| 58 | * M. Welsh, 6 July 1996 | |
| 59 | * | |
| 60 | * | |
| 61 | */ |