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ATH(4)                   BSD Kernel Interfaces Manual                   ATH(4)

NAME
     ath -- Atheros IEEE 802.11a/b/g wireless network device with GPIO

SYNOPSIS
     ath* at pci? dev ? function ?
     ath* at cardbus? dev ? function ?
     gpio* at ath?

DESCRIPTION
     The ath driver provides support for wireless network devices based on the
     Atheros AR5210, AR5211, and AR5212 chips.

     All host/device interaction is via DMA.  The ath driver encapsulates all
     IP and ARP traffic as 802.11 frames, though it can receive either 802.11
     or 802.3 frames.  Transmit speed and operating mode is selectable and
     depends on the specific chipset.

     Support for the various devices is as follows:

     AR5210  These devices support 802.11a operation with transmit speeds of 6
             Mbps, 9 Mbps, 12 Mbps, 18 Mbps, 24 Mbps, 36 Mbps, 48 Mbps, and 54
             Mbps.

     AR5211  These devices support 802.11a and 802.11b operation with transmit
             speeds as above for 802.11a and 1Mbps, 2Mbps, 5.5 Mbps, and
             11Mbps for 802.11b operation.

     AR5212  These devices support 802.11a, 802.11b, and 802.11g operation
             with transmit speeds as above for 802.11a, 802.11b, and 802.11g
             operation (802.11g speeds are the same as for 802.11a speeds).

     All chips also support an Atheros Turbo Mode (TM) that operates in the
     802.11a frequency range with 2x the transmit speeds.  (This mode is, how-
     ever, only interoperable with other Atheros-based devices.)

     The actual transmit speed used is dependent on signal quality and the
     ``rate control'' algorithm employed by the driver.

     These are the modes the ath driver can operate in:

     BSS mode       Also known as infrastructure mode, this is used when asso-
                    ciating with an access point, through which all traffic
                    passes.  This mode is the default.

     IBSS mode      Also known as IEEE ad-hoc mode or peer-to-peer mode.  This
                    is the standardized method of operating without an access
                    point.  Stations associate with a service set.  However,
                    actual connections between stations are peer-to-peer.

     Host AP        In this mode the adapter acts as an access point (base
                    station) for other cards.

     monitor mode   In this mode the driver is able to receive packets without
                    associating with an access point.  This disables the
                    internal receive filter and enables the card to capture
                    packets from networks which it wouldn't normally have
                    access to, or to scan for access points.

     The ath driver can be configured to use Wired Equivalent Privacy (WEP) or
     Wi-Fi Protected Access (WPA-PSK and WPA2-PSK).  WPA is the current
     encryption standard for wireless networks.  It is strongly recommended
     that WEP not be used as the sole mechanism to secure wireless communica-
     tion, due to serious weaknesses in it.

     AR5211 and AR5212 support the AES, TKIP, and Michael cryptographic opera-
     tions required for WPA in hardware but at this time the driver does not
     support them.

     The ath driver can be configured at runtime with ifconfig(8) or on boot
     with hostname.if(5).

HARDWARE
     Devices supported by the ath driver come in either CardBus or Mini PCI
     packages.  Wireless cards in CardBus slots may be inserted and ejected on
     the fly.

     The following cards are among those supported by the ath driver:

           Card                   Chip      Bus         Standard
           3Com 3CRPAG175         AR5212    CardBus     a/b/g
           Cisco AIR-CB21AG       AR5212    CardBus     a/b/g
           D-Link DWL-A650        AR5210    CardBus     a
           D-Link DWL-AB650       AR5211    CardBus     a/b
           D-Link DWL-A520        AR5210    PCI         a
           Elecom LD-WL54         AR5211    CardBus     a
           IBM 11ABG WL LAN       AR5212    Mini PCI    a/b/g
           Linksys WPC51AB        AR5211    CardBus     a/b
           Netgear WAB501         AR5211    CardBus     a/b
           Planet WL-3560         AR5211    CardBus     a/b/g
           Proxim Skyline 4030    AR5210    CardBus     a
           Proxim Skyline 4032    AR5210    PCI         a
           Senao NL-5354MP        AR5212    Mini PCI    a/b/g
           SMC SMC2735W           AR5210    CardBus     a
           Sony PCWA-C500         AR5210    CardBus     a
           Wistron CM9            AR5212    Mini PCI    a/b/g

EXAMPLES
     The following example scans for available networks:

           # ifconfig ath0 scan

     The following hostname.if(5) example configures ath0 to join network
     ``mynwid'', using WPA key ``mywpakey'', obtaining an IP address using
     DHCP:

           nwid mynwid
           wpakey mywpakey
           dhcp

     The following hostname.if(5) example creates a host-based access point on
     boot:

           inet 192.168.1.1 255.255.255.0
           mediaopt hostap
           nwid mynwid
           wpakey mywpakey

DIAGNOSTICS
     ath0: unable to attach hardware; HAL status N  The Hardware Access Layer
     was unable to configure the hardware as requested.  The status code is
     explained in the HAL include file sys/dev/ic/ar5xxx.h.

     ath0: failed to allocate descriptors: N  The driver was unable to allo-
     cate contiguous memory for the transmit and receive descriptors.  This
     usually indicates system memory is scarce and/or fragmented.

     ath0: unable to setup a data xmit queue!  The request to the HAL to set
     up the transmit queue for normal data frames failed.  This should not
     happen.

     ath0: unable to setup a beacon xmit queue!  The request to the HAL to set
     up the transmit queue for 802.11 beacon frames failed.  This should not
     happen.

     ath0: hardware error; resetting  An unrecoverable error in the hardware
     occurred.  Errors of this sort include unrecoverable DMA errors.  The
     driver will reset the hardware and continue.

     ath0: rx FIFO overrun; resetting  The receive FIFO in the hardware over-
     flowed before the data could be transferred to the host.  This typically
     occurs because the hardware ran short of receive descriptors and had no
     place to transfer received data.  The driver will reset the hardware and
     continue.

     ath0: unable to reset hardware; hal status N  The Hardware Access Layer
     was unable to reset the hardware as requested.  The status code is
     explained in the HAL include file /sys/dev/ic/ar5xxx.h.  This should not
     happen.

     ath0: unable to initialize the key cache  The driver was unable to ini-
     tialize the hardware key cache.  This should not happen.

     ath0: unable to start recv logic  The driver was unable to restart frame
     reception.  This should not happen.

     ath0: device timeout  A frame dispatched to the hardware for transmission
     did not complete in time.  The driver will reset the hardware and con-
     tinue.  This should not happen.

     ath0: bogus xmit rate 0xNNNN  An invalid transmit rate was specified for
     an outgoing frame.  The frame is discarded.  This should not happen.

     ath0: ath_chan_set: unable to reset channel N (X MHz)  The Hardware
     Access Layer was unable to reset the hardware when switching channels
     during scanning.  This should not happen.

     ath0: unable to allocate channel table  The driver was unable to allocate
     memory for the table used to hold the set of available channels.

     ath0: unable to collect channel list from hal  A problem occurred while
     querying the HAL to find the set of available channels for the device.
     This should not happen.

     ath0: failed to enable memory mapping  The driver was unable to enable
     memory-mapped I/O to the PCI device registers.  This should not happen.

     ath0: failed to enable bus mastering  The driver was unable to enable the
     device as a PCI bus master for doing DMA.  This should not happen.

     ath0: cannot map register space  The driver was unable to map the device
     registers into the host address space.  This should not happen.

     ath0: could not map interrupt  The driver was unable to allocate an IRQ
     for the device interrupt.  This should not happen.

     ath0: could not establish interrupt  The driver was unable to install the
     device interrupt handler.  This should not happen.

SEE ALSO
     arp(4), cardbus(4), gpio(4), ifmedia(4), intro(4), netintro(4), pci(4),
     hostname.if(5), gpioctl(8), hostapd(8), ifconfig(8)

HISTORY
     The ath device driver first appeared in FreeBSD 5.2 using a binary-only
     HAL module which was ported to NetBSD 2.0.  The driver using a free HAL-
     replacement first appeared in OpenBSD 3.7.

AUTHORS
     The ath driver was written by Sam Leffler, and was ported to OpenBSD by
     Reyk Floeter <reyk@openbsd.org> who also wrote a free replacement of the
     binary-only HAL.

CAVEATS
     Different regulatory domains may not be able to communicate with each
     other with 802.11a as different regulatory domains do not necessarily
     have overlapping channels.

     Host AP mode doesn't support power saving.  Clients attempting to use
     power saving mode may experience significant packet loss (disabling power
     saving on the client will fix this).

BUGS
     Performance in lossy environments is suboptimal.  The algorithm used to
     select the rate for transmitted packets is very simplistic.  There is no
     software retransmit; only hardware retransmit is used.  Contributors are
     encouraged to replace the existing rate control algorithm with a better
     one.

     The driver does not fully enable power-save operation of the chip; conse-
     quently power use is suboptimal.

BSD                             March 28, 2017                             BSD