I have rewritten Documentation/networking/bcm43xx.txt. I would appreciate your
comments.
Thanks,
Larry
=========================
Index: wireless-2.6/Documentation/networking/bcm43xx.txt
===================================================================
--- wireless-2.6.orig/Documentation/networking/bcm43xx.txt
+++ wireless-2.6/Documentation/networking/bcm43xx.txt
@@ -2,35 +2,77 @@
BCM43xx Linux Driver Project
============================
-About this software
--------------------
-
-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/
-
-The project page is http://bcm43xx.berlios.de/
-
-
-Requirements
+Introduction
------------
-1) Linux Kernel 2.6.16 or later
- http://www.kernel.org/
-
- You may want to configure your kernel with:
-
- CONFIG_DEBUG_FS (optional):
- -> Kernel hacking
- -> Debug Filesystem
-
-2) SoftMAC IEEE 802.11 Networking Stack extension and patched ieee80211
- modules:
- http://softmac.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 access
+point 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 developend 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 dstributed
+with the kernel source, and is prebuilt in most, if not all, distributions.
+There is, however, additional software that is required. Because the firmware
+used by the processor in the Broadcom chip is copyrighted, it is not possible
+for any third party to distribute it. 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 rev 0x127 (V3) firmware is
+
+http://downloads.openwrt.org/sources/wl_apsta-3.130.20.0.o.
+
+Once this file is downloaded, the command 'bcm43xx-fwcutter -i <filename>'
will list
+the "blobs" of microcode in the file. 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
[EMAIL PROTECTED]
+
+Although the driver has been in-kernel since 2.6.17, the earlier versions are
quite
+limited in their capability. Patches for each of the stable kernel versions
from
+2.6.18 onward are available to include all features of later versions. These
will
+be needed if you use a BCM4318, or a PCI-E 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 <kernel version>_combined_patch.
Of
+course you will need kernel source, either downloaded from kernel.org, or the
source
+from your distribution.
-3) Firmware Files
- 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.
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