Open source Atheros HAL to help Wifi developers under Linux
WiFi chipset maker Atheros announced that it has published the source code for a Wifi hardware abstraction layer (HAL) for Atheros chipsets. The announcement was made by Luis R. Rodriguez, a WiFi developer at Atheros, who stated that the HAL source code is licensed under the ISC licence, a modified BSD licence.
The new HAL is not the same as the driver in MadWifi, which was not been accepted into the Linux kernel because it contains proprietary code. The MadWifi HAL prevents direct access to the Wifi hardware in order to ensure that, for example, only the permitted Wifi channels can be set in UK. The developers of the MadWifi driver lived with the restrictions of the HAL, even though it made parts of the software project a closed black box for them. To try and free themselves, other developers ported the OpenBSD ath5k driver for IEEE 802.11a/b/g to Linux last year. Ath5k has no proprietary parts, depending instead on OpenHAL. The Ath5k driver has incorporated into the Linux kernel sources since version 2.6.25.
Rodriguez says the HAL that has now been published can be used as a source of documentation to help further development of ath5k as a WiFi Linux driver. Rodriguez is one of the ath5k driver's developers, but he is also one of the team working on the new ath9k driver, which supports draft IEEE 802.11n hardware and which recently became part of the 2.6.27 Linux kernel.