$Id: //depot/sw/linuxsrc/src/802_11/madwifi/hal/main/README#5 $


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

* Copyright (c) 2002-2006 Sam Leffler.
* Copyright (c) 2002-2006 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 local regulatory agency rules.  In the United States
the FCC requires that a radio transmitter 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" on Linux; 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 many generations of Atheros 802.11 wireless devices that
are typically referred to by their programming model:

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 and mini-pci cards.  In addition many laptop
vendors use Atheros mini-pci cards for their builtin wireless
support.

The Atheors PCI vendor id is 0x168c.  The file ah_devid.h lists most
known PCI device id's but is not exhaustive.  Some vendors program
their own vendor and/or device id's to aid in BIOS-locking mini-pci
cards in laptops.