BCM43xx Linux Driver Project ============================ Introduction ------------ Many of the wireless devices found in modern notebook computers are based on the wireless chips produced by Broadcom. These devices have been a problem for Linux users as there is no open-source driver available. In addition, Broadcom has not released specifications for the device, and driver availability has been limited to the binary-only form used in the GPL versions of AP hardware such as the Linksys WRT54G, and the Windows and OS X drivers. Before this project began, the only way to use these devices were to use the Windows or OS X drivers with either the Linuxant or ndiswrapper modules. There is a strong penalty if this method is used as loading the binary-only module "taints" the kernel, and no kernel developer will help diagnose any kernel problems. Development ----------- This driver has been developed using a clean-room technique that is described at http://bcm-specs.sipsolutions.net/ReverseEngineeringProcess. For legal reasons, none of the clean-room crew works on the on the Linux driver, and none of the Linux developers sees anything but the specifications, which are the ultimate product of the reverse-engineering group. Software -------- Since the release of the 2.6.17 kernel, the bcm43xx driver has been distributed with the kernel source, and is prebuilt in most, if not all, distributions. There is, however, additional software that is required. The firmware used by the chip is the intellectual property of Broadcom and they have not given the bcm43xx team redistribution rights to this firmware. Since we cannot legally redistribute the firmware we cannot include it with the driver. Furthermore, it cannot be placed in the downloadable archives of any distributing organization; therefore, the user is responsible for obtaining the firmware and placing it in the appropriate location so that the driver can find it when initializing. To help with this process, the bcm43xx developers provide a separate program named bcm43xx-fwcutter to "cut" the firmware out of a Windows or OS X driver and write the extracted files to the proper location. This program is usually provided with the distribution; however, it may be downloaded from http://developer.berlios.de/project/showfiles.php?group_id=4547 The firmware is available in two versions. V3 firmware is used with the in-kernel bcm43xx driver that uses a software MAC layer called SoftMAC, and will have a microcode revision of 0x127 or smaller. The V4 firmware is used by an out-of-kernel driver employing a variation of the Devicescape MAC layer known as d80211. Once bcm43xx-d80211 reaches a satisfactory level of development, it will replace bcm43xx-softmac in the kernel as it is much more flexible and powerful. A source for the latest V3 firmware is http://downloads.openwrt.org/sources/wl_apsta-3.130.20.0.o Once this file is downloaded, the command 'bcm43xx-fwcutter -w ' will extract the microcode and write it to directory . The correct directory will depend on your distribution; however, most use '/lib/firmware'. Once this step is completed, the bcm3xx driver should load when the system is booted. To see any messages relating to the driver, issue the command 'dmesg | grep bcm43xx' from a terminal window. If there are any problems, please send that output to Bcm43xx-dev@lists.berlios.de. Although the driver has been in-kernel since 2.6.17, the earliest version is quite limited in its capability. Patches that include all features of later versions are available for the stable kernel versions from 2.6.18. These will be needed if you use a BCM4318, or a PCI Express version (BCM4311 and BCM4312). In addition, if you have an early BCM4306 and more than 1 GB RAM, your kernel will need to be patched. These patches, which are being updated regularly, are available at ftp://lwfinger.dynalias.org/patches. Look for combined_2.6.YY.patch. Of course you will need kernel source downloaded from kernel.org, or the source from your distribution. If you build your own kernel, please enable CONFIG_BCM43XX_DEBUG and CONFIG_IEEE80211_SOFTMAC_DEBUG. The log information provided is essential for solving any problems.