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_pci
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"
if_ath_pci_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.
Please note that from FreeBSD-9.0, the
ath
driver does not include the PCI/PCIe bus glue. The same driver supports
multiple underlying bus types, including PCI/PCIe, but also embedded (AHB) and
USB in the future.
To enable use for PCI/PCIe systems, see the
ath_pci(4) driver. For embedded systems which use
the AHB to connect the wireless MAC, see the
ath_ahb(4) driver.
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.
EXAMPLES¶
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 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 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.