Saturday, January 17, 2009

one more option for embedded Linux WiFi hardware

There's now one more 802.11b/g wireless chipset available to use in your next embedded Linux system. Thanks to the Blackfin folks at Analog Devices, we now have a driver for the Marvell '8686 chipset using a GSPI interface suitable for many embedded applications. We also fixed an alignment bug in the core driver so that things work on CPUs such as Blackfin and AVR32. Embedded WiFi modules with this chipset are available from several vendors. The new driver, libertas_spi, is available in wireless-testing and coming to a future kernel (2.6.30, most likely).

GSPI is very easy to interface as it consists of a normal SPI bus, an IRQ line, and one GPIO line that acts as a chip select signal (as such, be sure to enable CONFIG_GENERIC_GPIO in your kernel config in order to build the new libertas_spi driver). The GPIO-style chip select is different from a typical SPI chip select in that the chip select stays asserted for an arbitrary number of SPI bus transactions.

Wednesday, January 7, 2009

draft-802.11s mesh in the 2.6.28 kernel

The 2.6.28 kernel, released on Dec. 25th '08, brings several nice improvements to the draft-802.11s mesh support in mac80211:
  • mesh support in the ath5k driver, which supports most Atheros 802.11b/g hardware.
  • mesh parameters can now be adjusted through nl80211 via the iw user space tool instead of using debugfs.
  • initial work on MPP support -- this will allow Mesh Point interfaces to be bridged with other interfaces.
  • several bug fixes and improvements as well as some reorganization of the code.