MADWIFI: Multimode Atheros Driver for WiFi on Linux =================================================== * Copyright (c) 2002-2005 Sam Leffler. All rights reserved. Read the file COPYRIGHT for the complete copyright. Requirements ------------ - Configured kernel sources of the target kernel. Most Linux distributions provide a kernel development package - it should suffice. - Wireless Extensions support - option CONFIG_NET_RADIO or CONFIG_WIRELESS_EXT in kernel .config file, whichever is available. - Sysctl support - option CONFIG_SYSCTL in kernel .config file. - Crypto API support - option CONFIG_CRYPTO in kernel .config file (AES support is used if present, otherwise the AES-CCMP cipher module falls back to a private implementation). - gcc of the same version that was used to compile the kernel. At least make sure that the first two version numbers or the compiler are the same (e.g. it's OK to use gcc 3.4.6 to compile MadWifi if the kernel was compiled by gcc 3.4.2). Ignoring this rule will cause "Invalid module format" errors during module load. Linux kernels starting with version 2.6.13 should work without problems. Due to quick pace of Linux development, there is no way compatibility with the future 2.6 kernels can be ensured. However, the latest 2.6 kernel at the time of the release should be expected to work. For AHB support, Linux 2.6.15 or newer is required. Automatic module loading support (CONFIG_KMOD) is highly recommended; otherwise, you'll need to load all required modules manually. Building the driver ------------------- The driver is built using the Linux kernel build mechanism. This means you must have some part of the kernel source distribution installed on the machine where you want to build the driver. In particular, the kernel include files, makefiles, build scripts and configuration must be available. This will be present if you built your kernel from source. Otherwise you may need to install an additional kernel development package from your distribution that would match your kernel. For example, the development package for the default kernel is called linux-headers on Debian and kernel-devel on Fedora Core. Installing a package with full kernel sources should not be generally necessary. Note: in the following examples "$" stands for your system prompt; you're not expected to type that as part of the actual command. "#" stands for the command prompt when the commands must be executed by root. Most people can just type: $ make in the top-level MadWifi source directory to build all the modules for the currently running system. You MUST do a "make clean" before compiling for a different version of Linux. If you want to compile MadWifi for a different kernel, you need to specify the location of the kernel build tree, e.g.: $ make KERNELPATH=/usr/src/linux-3.12 Note that you can also specify this path by setting an environment variable; e.g. $ export KERNELPATH=/usr/src/linux-3.12 $ make If the kernel was built outside the source directory, KERNELPATH should point to the output directory where .config is located, not to the sources. Cross-compiling --------------- The build system is designed to support cross-compiling without any modification to the distribution files. It should be sufficient to specify any parameters on the make command line. In most cases, only KERNELPATH, ARCH and CROSS_COMPILE need to be defined. ARCH is the architecture of the kernel. CROSS_COMPILE is the prefix for cross-compiling tools. For instance, if compiling for ARM and the cross compiler is called arm-linux-gcc, set ARCH to "arm" and CROSS_COMPILE to "arm-linux-": $ make KERNELPATH=/usr/src/linux-arm ARCH=arm CROSS_COMPILE=arm-linux- If the compiler needs additional flags to compile userspace binaries, you can redefine CC to include those flags. When installing MadWifi, set DESTDIR to the root of the target filesystem, so that the cross-compiled binaries don't overwrite the native ones. Loading the modules ------------------- Building the software will generate numerous loadable modules: ath_pci Atheros driver for PCI/Cardbus devices ath_hal Atheros HAL wlan 802.11 support layer wlan_wep WEP cipher support wlan_tkip TKIP cipher support wlan_ccmp AES-CCMP cipher support wlan_xauth external authenticator wlan_acl MAC ACL support for AP operation wlan_scan_ap AP scanning support wlan_scan_sta station scanning support ath_rate_onoe ONOE rate control ath_rate_amrr AMRR rate control ath_rate_sample SAMPLE rate control The ath_pci module must be loaded either manually or by the system, e.g. through the hotplug or card manager support. The remaining modules are loaded automatically as needed, so after doing a "make install" you only need to run following: # modprobe ath_pci For automatic module loading you may need to modify your system's configuration files so the necessary modules are loaded when an Atheros device is recognized. The exact procedure varies from system to system. There are module parameters available to fit your needs, e.g. you can set the countrycode manually if your card's EEPROM does not contain the correct one for your location. See http://www.unicode.org/onlinedat/countries.html to find your code. To activate German frequencies you would specify: # modprobe ath_pci countrycode=276 MadWifi currently provides four different rate control algorithms, ONOE, AMRR, SAMPLE and MINSTREL. SAMPLE and MINSTREL are both very advanced, but MINSTREL is quite new. Consequently, SAMPLE is used by default. In order to make MadWifi use e.g. AMRR instead, you have to specify that as the module parameter e.g. # modprobe ath_pci ratectl=amrr NOTE: Changing the rate control is only required (and recommended) for users who want to setup an access point using MadWifi in difficult (e.g. lossy) environments and who know what they are doing. To see all available module parameters type: $ modinfo ath_pci Integrating into the kernel sources ----------------------------------- It is also possible to patch Linux kernel sources to integrate MadWifi directly into the kernel tree. This allows building MadWifi as part of the kernel. This could be useful for embedded systems that don't support loadable modules. Please refer to patch-kernel/README for details. Further information ------------------- Further information on how to work with the driver can be found in the file README. In addition, the project's wiki has a lot of valuable information: http://madwifi-project.org/