ath(4) [FreeBSD WIKI]

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====== Atheros wireless driver support ======

%%|%% [[dev/ath(4)|Driver]] | [[dev/ath_hal(4)|HAL]] | [[dev/ath_hal(4)/HardwareSupport|Supported Hardware]] | [[dev/ath(4)/80211n|802.11n support]] | [[dev/ath(4)/Debugging|Debugging]] |

This is the driver for the Atheros PCI/PCIe NICs.

===== Supported Hardware =====

The in-tree driver supports all of the Atheros PCI/PCIe NICs. This includes the pre-11n chipsets and all 11n chipsets up to the AR9227/AR9287 (using sys/dev/ath/ath_hal/) and AR9380 and later (using sys/contrib/dev/ath/ath_hal/).

Notably - this doesn't yet support the AR5513 MIMO 802.11abg NIC, the AR5523 NICs (AR5212 + USB), the AR7010 series USB NICs, or the AR9271 series USB NICs.

Please see the [[dev/ath_hal(4)/HardwareSupport|Hal Hardware Support Page]] for further more information.

===== Operating Modes =====

  * 802.11a (5GHz)
  * 802.11bg (2GHz)
  * Half and Quarter rate modes in 5GHz for AR5212 family NICs, AR5416, AR9130, AR9160, AR9280, AR9285 (specifically not AR9287 at the moment)
  * Turbo (static 40mhz mode) for AR5212 family NICs
  * 900mhz NIC support (TODO: which NICs)
  * 802.11na (5GHz) and 802.11ng (2.4GHz), 1, 2 and 3 stream operation (MCS0-23), HT/20 and HT/40 channel width, short-GI
  * Mesh, 802.11n support, TDMA support
  * STA powersave support
  * AP powersave support

===== Driver Components =====

  * Rate control: Please see the [[dev/ath_rate(4)|rate control page]] for more information.
  * Ambient/Automatic Noise Immunity (ANI): Please see the [[dev/ath_hal(4)/AutomaticNoiseImmunity|ANI page]] for more information.
  * Radar pulse detection: Please see the [[dev/ath_hal(4)/RadarDetection|HAL Radar Detection]] page. This includes links to some relevant Atheros Patents. There's also some initial software support for extracting the information out via userland at [[dev/ath(4)/RadarFFT]].
  * 802.11n support: Please see the [[dev/ath(4)/80211n]] page for further information.
  * HAL: Please see the [[dev/ath_hal(4)|HAL device page]] for more information.

===== Bug List =====

  * Check %%FreeBSD%% GNATS for [[http://www.freebsd.org/cgi/query-pr-summary.cgi?responsible=freebsd-wireless|bugs filed to freebsd-wireless]]

===== Work in progress =====

| RIFS | Unimplemented | Unimplemented |
| Radar Detection | In progress | Unimplemented |
| Non-aggregate software retry support | Planned | This requires some very strict retransmission behaviour in order to ensure frames aren't transmitted out of order |
| AP PS-POLL and uAPSD support | In progress | PS-POLL done; uAPSD will follow |
| 802.11n TDMA support | In progress | 802.11n rates work, A-MSDU support is needed to reach full 802.11n throughput |
| 802.11n mesh support | Planned | Planned |
| Add/document MCI bluetooth coex support | Planned | Planned |
| PAPRD for AR9380 and later | Planned | Planned |

===== Small Project Wish List =====

The following is a set of simple projects which interested developers can use to get familiar with the ath/hal codebase.

  * Bluetooth Coexistence for AR9280/AR9285 - the routines have been ported; but require some integration work and testing.
  * RFKill for AR5416 and later (both software and hardware) - investigate how it's done for the previous chipsets (AR5212 in particular) and what ath9k does; then plan out a implementation and testing plan.
  * Tidy up the build structure for the ath tools so they can be included in the system by default?

===== Larger Project Wish List =====

  * Support channel busy surveys (a la mac80211.)
  * (Re) Test long link support for AR5212/AR5213 and derivatives - this essentially tweaks the ACK, RTS, CTS and various IFS timings to support long distance links.
  * Implement long link support for AR5416 and later chipsets
  * Investigate and fix power saving mode(s).
  * ATIM?
  * Auto-sleep support in AR9280 and later?
  * AR9271 and USB support in the HAL - a pre-requisite for supporting the 11n NICs after the AR9170-based devices.

===== Completed Wish List =====

  * (Re) Test Quarter/Half rate support for the AR5212/AR5213 and derivatives.
  * Implement Quarter/Half rate support for AR5416 and later chipsets - non-11n and 11n modes.
  * Implement software TX aggregation and retransmit for AR5416 and later chipsets in 11n mode.
  * The HAL configuration variables are global (eg debug, beacon timer adjustments, ALQ logging.) It would be nice to have these per-HAL instance - so move them to the public part of the ath_hal struct and initialise them on device attach. They're not per-vif; they're per-device.
  * I've added quite a few more statistics to the per-device ioctl statistics (sys/dev/ath/if_athioctl.h); athstats needs to be taught about these new statistics so they can be reported.
  * (Re) Test TDMA support for AR5212/AR5213 and derivatives.
  * Implement TDMA support for AR5416 and later chipsets - non-11n and 11n modes.
  * Implement per-packet TPC (Transmission Power Control) for chipsets which support it - required for full DFS support.
  * Modify if_ath.c to report the per-radio control/extension noise floor and RSSI - net80211 has already been taught about it, ath_hal has been taught about how to export the statistics; all that's needed is the glue in if_ath.c.

===== Fixed Issues =====

| ath multi-SSID support - < AR5416 | Fixed | This needs testing - both open and WEP/WPA |
| ath multi-SSID support - >= AR5416 | Fixed | Some further testing would be nice! |
| ath multicast search key support | Fixed | Fixed |
| ath 11n RX support | Fixed | Completed |
| net80211 HT/20 support - 2.4ghz | Fixed | Completed |
| net80211 HT/20 support - 5ghz | Fixed | Completed |
| net80211 HT/40 support | Fixed | Completed |
| net80211 short-GI support | Fixed | Completed |
| net80211 11n STA mode | Fixed | Completed |
| net80211 11n AP mode | Fixed | Completed |
| net80211 A-MPDU/A-MSDU RX support | Fixed | A-MPDU issues resolved; Ath cards require ampdudensity of 8 |

===== Useful Links =====

  * Atheros Patent: Adaptive Noise Immunity: [[http://www.freepatentsonline.com/7349503.html]]
  * Atheros Patent: Noise Floor Calibration / Signal Strength Detection: [[http://www.freepatentsonline.com/7245893.html]]
  * Atheros Patent: Offset/Gain calibration for ADCs: [[http://www.freepatentsonline.com/7541952.html]]
  * Atheros Patent: Radar Pulse Detection/Estimation: [[http://ip.com/patent/US6891496]]
  * May 2008 IEEE: Atheros 2.4/5 Ghz 2x2 MIMO %%SoC%% (talk slides?): [[https://web.archive.org/web/20080830021352/http://www.ewh.ieee.org/r6/scv/ssc/May2008_WLAN.pdf]]