.\"     $NetBSD: atw.4,v 1.12 2010/01/15 19:24:49 joerg Exp $
.\"
.\" Copyright (c) 2003
.\"	David Young <dyoung@NetBSD.org>. All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
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.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
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.\" THIS SOFTWARE IS PROVIDED BY David Young AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL David Young
.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\"	$Id: atw.4,v 1.12 2010/01/15 19:24:49 joerg Exp $
.\"
.Dd June 5, 2004
.Dt ATW 4
.Os
.Sh NAME
.Nm atw
.Nd ADMtek ADM8211 802.11 wireless network driver
.Sh SYNOPSIS
.Cd "atw* at cardbus? function ?"
.Cd "atw* at pci? dev ? function ?"
.Sh DESCRIPTION
The
.Nm
driver supports PCI/CardBus 802.11b wireless adapters based on the
ADMtek ADM8211.
.Pp
The ADM8211 is a bus-mastering 802.11 Media Access Controller (MAC)
which is derived from ADMtek's Tulip clones (see
.Xr tlp 4 ) .
It supports contention-free traffic (with an 802.11 Point Coordinator),
64/128-bit WEP encryption, and 802.11 power-saving.
The ADM8211 integrates an RF3000 baseband processor (BBP) by RF
Microdevices.
.Pp
In a typical application, the ADM8211 is coupled with an RF front-end
by RFMD and a Silicon Laboratories Si4126 RF/IF synthesizer.
.Pp
With the ADM8211, the division of labor between the host and NIC
is different than with firmware-based NICs such as
.Xr an 4 ,
.Xr awi 4 ,
and
.Xr wi 4 .
The ADM8211 is still responsible for real-time 802.11 functions
such as sending ACK/RTS/CTS/ATIM frames, sending beacons, and
answering CF polls from the access point, but the host takes
responsibility for providing 802.11 functions such as scanning,
association, and authentication.
The host is also responsible for programming both the BBP and the
RF/IF synthesizer.
.Pp
.Nm
contains incomplete support for the ADM8211's WEP encryption/decryption
engine.
.Nm
does not yet support hardware WEP decryption, however, it will use
the ADM8211's crypto engine to encrypt transmitted frames.
Documentation from ADMtek claims that, in addition to the 4 128-bit
shared WEP keys, the ADM8211 will store WEP key pairs for up to 20
peers.
The documentation provides no details, hence
.Nm
does not support the 20 key-pairs.
.Pp
The ADM8211 operates in 802.11 infrastructure mode (with an access
point) and in 802.11 ad hoc mode (without an access point) at 1,
2, 5.5, and 11Mbps.
ADMtek says that the ADM8211 cannot operate as an access point.
.Pp
The operating mode is selected using the
.Xr ifconfig 8
utility.
For more information on configuring this device, see
.Xr ifconfig 8
and
.Xr ifmedia 4 .
.Sh HARDWARE
Cards supported by the
.Nm
driver include:
.Pp
.Bl -item -offset indent -compact
.It
D-Link DWL-650 Rev. ?? CardBus card
.It
D-Link DWL-520 Rev. C1 PCI card
.It
LanReady WP2000 PCI card
.It
TrendNet TEW-221PC CardBus card
.It
Xterasys XN2511B PCI card
.It
.El
.Sh DIAGNOSTICS
.Bl -diag
.It "atw0: failed to tune channel %d"
The driver failed to tune the radio to a new channel.
The radio remains tuned to the old channel.
.It "atw0: atw_si4136_write wrote %08x, SYNCTL still busy"
The driver waited 100ms without seeing an indication that the
ADM8211 had finished writing a register on the Si4126 RF/IF
synthesizer.
.It "atw0: device timeout"
The ADM8211 failed to generate an interrupt to acknowledge a transmit
command.
.El
.Sh SEE ALSO
.Xr arp 4 ,
.Xr cardbus 4 ,
.Xr ifmedia 4 ,
.Xr netintro 4 ,
.Xr pci 4 ,
.Xr ifconfig 8
.Rs
.%T ADMtek
.%U http://www.admtek.com.tw
.Re
.Rs
.%T Silicon Laboratories
.%U http://www.silabs.com
.Re
.Rs
.%T RF Microdevicdes
.%U http://www.rfmd.com
.Re
.Sh HISTORY
The
.Nm
device driver first appeared in
.Nx 2.0 .
.Sh AUTHORS
.An -nosplit
The
.Nm
driver was written by
.An David Young
.Aq dyoung@NetBSD.org .
For features which the ADM8211 has in common with the DECchip 21x4x,
code was liberally borrowed from
.Xr tlp 4
by
.An Jason Thorpe
.Aq thorpej@NetBSD.org .
.Sh BUGS
The author does not fully understand what processing the duration
fields for the PLCP header and the 802.11 header undergo before
they are applied to a transmitted frame.
If the duration fields in transmitted frames are incorrect, the
performance of your network may suffer.
.Pp
The driver does not provide rate control when the media type is
set to autoselect.
.Pp
The driver lets you change to hostap mode, but it does not work
and it probably never will.
.Pp
The driver will sometimes complain that it cannot re-tune the radio
because the transmit process has not gone idle.
The author is investigating.
.Pp
Many features are still missing, especially WEP decryption and
802.11 power-saving.
.Pp
The ad hoc mode has not been rigorously tested.
IBSSs with the same SSID may not coalesce, but this should not
matter for most applications.
.Pp
The driver is untested in the ad-hoc demo mode of Lucent WaveLAN
cards.
.Pp
The ADM8211 supports 802.11 power-saving, however,
.Nm
does not support it yet.
For time-bounded service, the ADM8211 will interoperate with an
access point which implements the 802.11 Point Coordination Function,
however, this is also not supported.
.Pp
Combinations of an ADM8211 with either an Intersil or a Marvell RF
front-end are not supported.