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