xref: /linux/drivers/atm/nicstarmac.copyright (revision e5451c8f8330e03ad3cfa16048b4daf961af434f)
11da177e4SLinus Torvalds/* nicstar.c  v0.22  Jawaid Bazyar (bazyar@hypermall.com)
21da177e4SLinus Torvalds * nicstar.c, M. Welsh (matt.welsh@cl.cam.ac.uk)
31da177e4SLinus Torvalds *
41da177e4SLinus Torvalds * Hacked October, 1997 by Jawaid Bazyar, Interlink Advertising Services Inc.
51da177e4SLinus Torvalds * 	http://www.hypermall.com/
61da177e4SLinus Torvalds * 10/1/97 - commented out CFG_PHYIE bit - we don't care when the PHY
71da177e4SLinus Torvalds *	interrupts us (except possibly for removal/insertion of the cable?)
81da177e4SLinus Torvalds * 10/4/97 - began heavy inline documentation of the code. Corrected typos
91da177e4SLinus Torvalds *	and spelling mistakes.
101da177e4SLinus Torvalds * 10/5/97 - added code to handle PHY interrupts, disable PHY on
111da177e4SLinus Torvalds *	loss of link, and correctly re-enable PHY when link is
121da177e4SLinus Torvalds *	re-established. (put back CFG_PHYIE)
131da177e4SLinus Torvalds *
141da177e4SLinus Torvalds *   Modified to work with the IDT7721 nicstar -- AAL5 (tested) only.
151da177e4SLinus Torvalds *
16*7ff6e6f7SAdrian Bunk * R. D. Rechenmacher <ron@fnal.gov>, Aug. 6, 1997
171da177e4SLinus Torvalds *
181da177e4SLinus Torvalds * Linux driver for the IDT77201 NICStAR PCI ATM controller.
191da177e4SLinus Torvalds * PHY component is expected to be 155 Mbps S/UNI-Lite or IDT 77155;
201da177e4SLinus Torvalds * see init_nicstar() for PHY initialization to change this. This driver
211da177e4SLinus Torvalds * expects the Linux ATM stack to support scatter-gather lists
221da177e4SLinus Torvalds * (skb->atm.iovcnt != 0) for Rx skb's passed to vcc->push.
231da177e4SLinus Torvalds *
241da177e4SLinus Torvalds * Implementing minimal-copy of received data:
251da177e4SLinus Torvalds *   IDT always receives data into a small buffer, then large buffers
261da177e4SLinus Torvalds *     as needed. This means that data must always be copied to create
271da177e4SLinus Torvalds *     the linear buffer needed by most non-ATM protocol stacks (e.g. IP)
281da177e4SLinus Torvalds *     Fix is simple: make large buffers large enough to hold entire
291da177e4SLinus Torvalds *     SDU, and leave <small_buffer_data> bytes empty at the start. Then
301da177e4SLinus Torvalds *     copy small buffer contents to head of large buffer.
311da177e4SLinus Torvalds *   Trick is to avoid fragmenting Linux, due to need for a lot of large
321da177e4SLinus Torvalds *     buffers. This is done by 2 things:
331da177e4SLinus Torvalds *       1) skb->destructor / skb->atm.recycle_buffer
341da177e4SLinus Torvalds *            combined, allow nicstar_free_rx_skb to be called to
351da177e4SLinus Torvalds *            recycle large data buffers
361da177e4SLinus Torvalds *       2) skb_clone of received buffers
371da177e4SLinus Torvalds *   See nicstar_free_rx_skb and linearize_buffer for implementation
381da177e4SLinus Torvalds *     details.
391da177e4SLinus Torvalds *
401da177e4SLinus Torvalds *
411da177e4SLinus Torvalds *
421da177e4SLinus Torvalds * Copyright (c) 1996 University of Cambridge Computer Laboratory
431da177e4SLinus Torvalds *
441da177e4SLinus Torvalds *   This program is free software; you can redistribute it and/or modify
451da177e4SLinus Torvalds *   it under the terms of the GNU General Public License as published by
461da177e4SLinus Torvalds *   the Free Software Foundation; either version 2 of the License, or
471da177e4SLinus Torvalds *   (at your option) any later version.
481da177e4SLinus Torvalds *
491da177e4SLinus Torvalds *   This program is distributed in the hope that it will be useful,
501da177e4SLinus Torvalds *   but WITHOUT ANY WARRANTY; without even the implied warranty of
511da177e4SLinus Torvalds *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
521da177e4SLinus Torvalds *   GNU General Public License for more details.
531da177e4SLinus Torvalds *
541da177e4SLinus Torvalds *   You should have received a copy of the GNU General Public License
551da177e4SLinus Torvalds *   along with this program; if not, write to the Free Software
561da177e4SLinus Torvalds *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
571da177e4SLinus Torvalds *
581da177e4SLinus Torvalds * M. Welsh, 6 July 1996
591da177e4SLinus Torvalds *
601da177e4SLinus Torvalds *
611da177e4SLinus Torvalds */
62