I was able to get a USB Wifi adapter working on the ZedBoard in Linaro Ubuntu the other day, and I figured I'd share my results here. The process was not difficult, and only required a little tinkering. I used a DLink DWA-140 v.B2 adapter (which I was able to find on Amazon for ~$15), but this procedure has the potential to work for any adapter that is based on a Ralink chipset (Ralink devices typically have a name similar to rtxxxx). Here is what to do:
1) Get Linaro Ubuntu running on the ZedBoard using the Digilent kernel. Some documentation on how to do this just went up, and is available here:
http://www.digilentinc.com/Products/Detail.cfm?NavPath=2,66,1143&Prod=EMBEDDED-LINUX
The guide is called "Getting Started with Embedded Linux -- ZedBoard". You should follow the guide all the way through, because your going to need to configure the kernel source in the next step.
2) Next, the proper drivers need to be built into the kernel. On your Linux PC that has the Digilent Linux repo cloned, open a terminal and change into the linux-digilent directory. Run:
make ARCH=arm digilent_zed_defconfig
Then run:
make ARCH=arm menuconfig
Set (to 'y') the following options (leave any additional options that appear as their defaults):
Networking Support -> Wireless -> cfg80211 - wireless configuration API
Networking Support -> Wireless -> Generic IEEE 802.11 Networking Stack (mac80211)
Device Drivers -> Network device support -> Wireless LAN
Device Drivers -> Network device support -> Wireless LAN -> Ralink driver support
Device Drivers -> Network device support -> Wireless LAN -> Ralink driver support -> Ralink rt27xx/rt28xx/rt30xx
You may also need to build in additional drivers in the "Ralink driver support" menu so that the Ralink chipset on your device is supported. Exit menuconfig and save.
3) Build the kernel, and then insert the SD card you created with the GSwEL guide. Copy the newly built zImage over to the Fat partition of the SD card.
4) Insert the SD card into the ZedBoard and boot it up. Open up a terminal program on a PC and connect to the ZedBoard UART terminal. Also, ensure that the ZedBoard Ethernet port is connected to the internet.
5) At the UART terminal, run:
apt-get install linux-firmware
6) Once completed, connect your Wifi adapter, a keyboard, and a mouse to the USB-OTG port (via a hub). Disconnect the ethernet cable from the internet. At the Linaro desktop, you should see something that resembles a networking symbol in the upper right hand corner. Click on it using the USB mouse, and ensure "Enable Networking" and "Enable Wireless" are checked. If they are, then you should see a list of available networks. Connect to your wireless network, and your done! Try viewing some web sites in Firefox to test it out.
A helpful list of known issues with specific adapters can be found here: http://elinux.org/RPi_VerifiedPeripherals#Working_USB_Wi-Fi_Adapters
This information is targeted for the Raspberry Pi, but should still be helpful on the Zedboard.
Adding Wifi functionallity to the ZedBoard opens up the doors for some pretty cool projects, so have fun!
