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Diffstat (limited to 'Documentation/networking')
| -rw-r--r-- | Documentation/networking/bcm43xx.txt | 97 |
1 files changed, 75 insertions, 22 deletions
diff --git a/Documentation/networking/bcm43xx.txt b/Documentation/networking/bcm43xx.txt index 28541d2..a136721 100644 --- a/Documentation/networking/bcm43xx.txt +++ b/Documentation/networking/bcm43xx.txt @@ -2,35 +2,88 @@ BCM43xx Linux Driver Project ============================ -About this software -------------------- +Introduction +------------ -The goal of this project is to develop a linux driver for Broadcom -BCM43xx chips, based on the specification at -http://bcm-specs.sipsolutions.net/ +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. -The project page is http://bcm43xx.berlios.de/ +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. -Requirements ------------- +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 firwmare 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 -1) Linux Kernel 2.6.16 or later - http://www.kernel.org/ +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. - You may want to configure your kernel with: +A source for the latest V3 firmware is - CONFIG_DEBUG_FS (optional): - -> Kernel hacking - -> Debug Filesystem +http://downloads.openwrt.org/sources/wl_apsta-3.130.20.0.o -2) SoftMAC IEEE 802.11 Networking Stack extension and patched ieee80211 - modules: - http://softmac.sipsolutions.net/ +Once this file is downloaded, the command +'bcm43xx-fwcutter -w <dir> <filename>' +will extract the microcode and write it to directory +<dir>. 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. -3) Firmware Files +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. - Please try fwcutter. Fwcutter can extract the firmware from various - binary driver files. It supports driver files from Windows, MacOS and - Linux. You can get fwcutter from http://bcm43xx.berlios.de/. - Also, fwcutter comes with a README file for further instructions. +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. |
