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NAME

     ath - Atheros IEEE 802.11 wireless network driver

SYNOPSIS

     To compile this driver into the kernel, place the following lines in your
     kernel configuration file:

           device ath
           device ath_hal
           options AH_SUPPORT_AR5416
           device ath_rate_sample
           device wlan

     Alternatively, to load the driver as a module at boot time, place the
     following line in loader.conf(5):

           if_ath_load="YES"

DESCRIPTION

     The ath driver provides support for wireless network adapters based on
     the Atheros AR5210, AR5211, AR5212, and AR5416 programming APIs.  These
     APIs are used by a wide variety of chips; most all chips with a PCI
     and/or CardBus interface are supported.

     Supported features include 802.11 and 802.3 frames, power management,
     BSS, IBSS, MBSS, TDMA, and host-based access point operation modes.  All
     host/device interaction is via DMA.

     The ath driver encapsulates all IP and ARP traffic as 802.11 frames,
     however it can receive either 802.11 or 802.3 frames.  Transmit speed and
     operating mode is selectable and depends on the specific chipset.
     AR5210-based 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-based devices support 802.11a and 802.11b operation with transmit
     speeds as above for 802.11a operation and 1Mbps, 2Mbps, 5.5 Mbps and
     11Mbps for 802.11b operation.  AR5212-based devices support 802.11a,
     802.11b, and 802.11g operation with transmit speeds appropriate to each.
     AR5416-class devices are capable of 802.11n operation but are supported
     only in legacy modes (802.11a, 11b, 11g).  Most chips also support an
     Atheros Turbo Mode (TM) that operates in the 5Ghz frequency range with 2x
     the transmit speeds.  Some chips also support Turbo mode in the 2.4Ghz
     range with 802.11g though this support is not presently available due to
     regulatory requirements.  (Note that Turbo modes are, however, only
     interoperable with other Atheros-based devices.)  AR5212-based devices
     also support half- (10MHz) and quarter-width (5MHz) channels.  The actual
     transmit speed used is dependent on signal quality and the “rate control”
     algorithm employed by the driver.  All chips support WEP encryption.
     AR5212 and AR5416 parts have hardware support for the AES-CCM, TKIP, and
     Michael cryptographic operations required for WPA.  To enable encryption,
     use ifconfig(8) as shown below.

     The driver supports station, adhoc, adhoc-demo, hostap, mesh, wds, and
     monitor mode operation.  Multiple hostap virtual interfaces may be
     configured for simultaneous use on cards that use a 5212 part.  When
     multiple interfaces are configured each may have a separate mac address
     that is formed by setting the U/L bits in the mac address assigned to the
     underlying device.  Any number of wds virtual interfaces may be
     configured together with hostap interfaces.  Multiple station interfaces
     may be operated together with hostap interfaces to construct a wireless
     repeater device.  The driver also support tdma operation when compiled
     with options IEEE80211_SUPPORT_TDMA (which also enables the required
     802.11 support).  For more information on configuring this device, see
     ifconfig(8).

     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.

HARDWARE

     The ath driver supports all Atheros Cardbus and PCI cards, except those
     that are based on the AR5005VL chipset.

     A list of cards that are supported can be found at
     http://customerproducts.atheros.com/customerproducts/default.asp.

EXAMPLES

     Join an existing BSS network (ie: connect to an access point):

           ifconfig ath0 inet 192.168.0.20 netmask 0xffffff00

     Join a specific BSS network with network name “my_net”:

           ifconfig ath0 inet 192.168.0.20 netmask 0xffffff00 ssid my_net

     Join a specific BSS network with WEP encryption:

           ifconfig wlan0 create wlandev ath0
           ifconfig wlan0 inet 192.168.0.20 netmask 0xffffff00 ssid my_net \
                   wepmode on wepkey 0x8736639624

     Join/create an 802.11b IBSS network with network name “my_net”:

           ifconfig wlan0 create wlandev ath0 wlanmode adhoc
           ifconfig wlan0 inet 192.168.0.22 netmask 0xffffff00 ssid my_net \
                   mode 11b

     Create an 802.11g host-based access point:

           ifconfig wlan0 create wlandev ath0 wlanmode hostap
           ifconfig wlan0 inet 192.168.0.10 netmask 0xffffff00 ssid my_ap \
                   mode 11g

     Create an 802.11a mesh station:

           ifconfig wlan0 create wlandev ath0 wlanmode mesh
           ifconfig wlan0 meshid my_mesh mode 11a inet 192.168.0.10/24

     Create two virtual 802.11a host-based access points, one with with WEP
     enabled and one with no security, and bridge them to the fxp0 (wired)
     device:

           ifconfig wlan0 create wlandev ath0 wlanmode hostap \
                   ssid paying-customers wepmode on wepkey 0x1234567890 \
                   mode 11a up
           ifconfig wlan1 create wlandev ath0 wlanmode hostap bssid \
                   ssid freeloaders up
           ifconfig bridge0 create addm wlan0 addm wlan1 addm fxp0 up

     Create a master node in a two slot TDMA BSS configured to use 2.5
     millisecond slots.

           ifconfig wlan0 create wlandev ath0 wlanmode tdma \
                   ssid tdma-test tmdaslot 0 tdmaslotlen 2500 \
                   channel 36 up

DIAGNOSTICS

     ath%d: unable to attach hardware; HAL status %u  The Atheros Hardware
     Access Layer was unable to configure the hardware as requested.  The
     status code is explained in the HAL include file
     sys/contrib/dev/ath/ah.h.

     ath%d: failed to allocate descriptors: %d  The driver was unable to
     allocate contiguous memory for the transmit and receive descriptors.
     This usually indicates system memory is scarce and/or fragmented.

     ath%d: 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.

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

     ath%d: 802.11 address: %s  The MAC address programmed in the EEPROM is
     displayed.

     ath%d: 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.

     ath%d: rx FIFO overrun; resetting  The receive FIFO in the hardware
     overflowed 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.

     ath%d: unable to reset hardware; hal status %u  The Atheros Hardware
     Access Layer was unable to reset the hardware as requested.  The status
     code is explained in the HAL include file sys/contrib/dev/ath/ah.h.  This
     should not happen.

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

     ath%d: device timeout  A frame dispatched to the hardware for
     transmission did not complete in time.  The driver will reset the
     hardware and continue.  This should not happen.

     ath%d: bogus xmit rate 0x%x  An invalid transmit rate was specified for
     an outgoing frame.  The frame is discarded.  This should not happen.

     ath%d: ath_chan_set: unable to reset channel %u (%u Mhz)  The Atheros
     Hardware Access Layer was unable to reset the hardware when switching
     channels during scanning.  This should not happen.

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

     ath%d: 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.

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

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

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

SEE ALSO

     ath_hal(4), cardbus(4), intro(4), pcic(4), wlan(4), wlan_ccmp(4),
     wlan_tkip(4), wlan_wep(4), wlan_xauth(4), hostapd(8), ifconfig(8),
     wpa_supplicant(8)

HISTORY

     The ath device driver first appeared in FreeBSD 5.2.

CAVEATS

     Revision A1 of the D-LINK DWL-G520 and DWL-G650 are based on an Intersil
     PrismGT chip and are not supported by this driver.

BUGS

     There is no software retransmit; only hardware retransmit is used.

     The driver does not fully enable power-save operation of the chip in
     station mode; consequently power use is suboptimal (e.g. on a laptop).

     WPA is not supported for 5210 parts.