$Id: //depot/sw/linuxsrc/src/802_11/madwifi/hal/main/README#4 $


WARNING: THIS IS A BETA DISTRIBUTION.  THIS SOFTWARE HAS KNOWN PROBLEMS AND
WARNING: LIMITATIONS THAT WILL BE CORRECTED BEFORE A PRODUCTION RELEASE.
WARNING: USE AT YOUR OWN RISK!


Atheros Hardware Access Layer (HAL)
===================================

* Copyright (c) 2002-2005 Sam Leffler.
* Copyright (c) 2002-2005 Atheros Communications, Inc.
* All rights reserved.

Read the file COPYRIGHT for the complete copyright.

This code manages much of the chip-specific operation of the Atheros driver.
The HAL is provided in a binary-only form in order to comply with FCC
regulations.  In particular, a radio transmitter can only be operated at
power levels and on frequency channels for which it is approved.  The FCC
requires that a software-defined radio cannot be configured by a user
to operate outside the approved power levels and frequency channels.
This makes it difficult to open-source code that enforces limits on
the power levels, frequency channels and other parameters of the radio
transmitter.  See

http://ftp.fcc.gov/Bureaus/Engineering_Technology/Orders/2001/fcc01264.pdf

for the specific FCC regulation.  Because the module is provided in a
binary-only form it is marked "Proprietary"; this means when you load
it you will see messages that your system is now "tainted".

If you wish to use this driver on a platform for which an ath_hal
module is not already provided please contact the author.  Note that
this is only necessary for new _architectures_; the HAL is not tied to
any specific version of your operating system.


Atheros Hardware
================
There are currently 3 generations of Atheros 802.11 wireless devices:

5210	supports 11a only
5211	supports both 11a and 11b
5212	supports 11a, 11b, and 11g

These parts have been incorporated in a variety of retail products
including cardbus cards from DLink, Linksys, Netgear, and Proxim; and
mini-pci cards from some of these same vendors.  In addition many
laptop vendors use Atheros mini-pci cards for their builtin wireless
support.  An (incomplete) list of products that use Atheros parts is:

Netgear WAG511		D-Link DWL-AG520	Linksys WPC55AG
Netgear WAB501		D-Link DWL-AG650	Linksys WMP55AG
			D-Link DWL-AB650	Linksys WPC51AB

In general, if a device is identified as ``11a only'' it is almost
certain to contain an Atheros 5210 part in it.  All retail a+b
products use the 5211.  The latest generation of universal a+b+g
combo products use the 5212.  When in doubt check the PCI vendor
id with a tool like lspci, the Atheros vendor id is 0x168c; e.g.

   00:13.0 Ethernet controller: Unknown device 168c:0012 (rev 01)
