Atheros wireless driver support

| Driver | HAL | Supported Hardware | 802.11n support | Debugging |

Primary development is now in FreeBSD-HEAD.

This work attempts to bring in fixes both from Linux ath9k (from the wireless-testing branch), the Atheros HAL code (not currently open source) and from local testing.

The eventual aim is to support all current and past Atheros wireless devices with a clean, portable, documented driver and HAL.

Please see the Hal Hardware Support Page for more information.

• 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 and 2 stream operation (MCS0-15), HT/20 and HT/40 channel width, short-GI

• Rate control: Please see the rate control page for more information.
• Ambient/Automatic Noise Immunity (ANI): Please see the ANI page for more information.
• Radar pulse detection: Please see the 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 RadarFFT.
• 802.11n support: Please see the 80211n page for further information.
• HAL: Please see the HAL device page for more information.

• Check FreeBSD GNATS for bugs filed to freebsd-wireless

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?
• 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.

• Support channel busy surveys (a la mac80211.)
• (Re) Test Quarter/Half rate support for the AR5212/AR5213 and derivatives.
• (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 Quarter/Half rate support for AR5416 and later chipsets - non-11n and 11n modes.
• Implement long link support for AR5416 and later chipsets
• (Re) Test TDMA support for AR5212/AR5213 and derivatives.
• Implement TDMA support for AR5416 and later chipsets - non-11n and 11n modes.
• 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.
• Implement per-packet TPC (Transmission Power Control) for chipsets which support it - required for full DFS support.

• 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.

• 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 2×2 MIMO SoC (talk slides?): http://www.ewh.ieee.org/r6/scv/ssc/May2008_WLAN.pdf