/* 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 $Revision: 1.1 $ $Date: 1999/08/20 11:00:11 $ * * 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 * * */