Cisco Cisco MediaSense Release 9.1(1) Licensing Information

Open Source Used In Cisco MediaSense 11.5(1) 2773

* 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.

* 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