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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/dev/ath/ath_hal/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/dev/ath/ath_hal/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.