================================================================
MADWIFI: Multimode Atheros Driver for WiFi on Linux (VAP branch)
================================================================

* Copyright (c) 2002-2005 Sam Leffler.  All rights reserved.

Read the file COPYRIGHT for the complete copyright.


Requirements
============

o Kernel sources of the target kernel (some Linux distributions provide
  headers, makefiles and configuration data - it should suffice).
o Wireless Extensions support (14 or later, 17 preferred) - option
  CONFIG_NET_RADIO in kernel .config file.
o Sysctl support - option CONFIG_SYSCTL in kernel .config file.
o 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).
o gcc of same version that was used to compile the kernel (ignoring this
  will cause "Invalid module format" errors during module load).

2.4.x kernels starting with 2.4.20 and 2.6 kernels should work without
problems. Other kernel versions may require modifications, e.g. for
crypto support and/or updated wireless extensions.

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.

If you built your kernel from source then this will be present. 
Otherwise you may need to install some packages your distribution (look
for kernel-headers or kernel-devel).

Note: in the following examples "trouble%" stands for your system
prompt; you're not expected to type that as part of the actual
command.


Most people can just type:

trouble% 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; e.g. building for 2.6 after building for 2.4.

If you want to compile madwifi for a different kernel, you need to
specify the location of the kernel build tree, e.g.:

trouble% make KERNELPATH=/usr/src/linux-2.6.3

Note that you can also specify this path by setting an environment
variable; e.g.

trouble% export KERNELPATH=/usr/src/linux-2.6.3
trouble% make

If the kernel was built outside the source directory, KERNELPATH should
point to the output directory, not to the sources.

In rare cases you may also need to specify the kernel version using the
KERNELRELEASE variable.  This used to be necessary for the kernels that
had their exact version set during compilation.  For instance, some
distribution could ship a '2.6.10-4-686' kernel compiled from 2.6.10
sources.  If you still need to use the KERNELRELEASE option, please
report it.


Madwifi currently provides three different rate control algorithms,
ONOE, AMRR and SAMPLE. SAMPLE is the most advanced one and is used
by default. In order to make madwifi use AMRR instead, you have to
specify that via the ATH_RATE environment variable; e.g.

trouble% export ATH_RATE=ath_rate/amrr
trouble% make

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.


This distribution includes support for a variety of target platforms.
Because of the binary nature of the HAL not all platforms are
supported (the list grows as time permits).  The supported target
platforms can be found with:

trouble% ls hal/linux/*.inc
hal/linux/Makefile.inc          hal/linux/mips1-le-elf.inc
hal/linux/arm9-le-thumb-elf.inc hal/linux/mipsisa32-be-elf.inc
hal/linux/armv4-be-elf.inc      hal/linux/mipsisa32-le-elf.inc
hal/linux/armv4-le-elf.inc      hal/linux/powerpc-be-eabi.inc
hal/linux/i386-elf.inc          hal/linux/powerpc-le-eabi.inc
hal/linux/mips-be-elf.inc       hal/linux/sh4-le-elf.inc
hal/linux/mips-le-elf.inc       hal/linux/xscale-be-elf.inc
hal/linux/mips1-be-elf.inc

A target specifies the CPU architecture, byte order, and the ABI/file
format.  For most popular platforms, the build system will find the
appropriate files.  When cross-compiling or compiling for less common
platforms, the target platform should be specified using the TARGET
variable, e.g:

trouble% make TARGET=armv4-le-elf

Consult the contents of the .inc file to find out what the target
platform is and what toolchain was used to build the HAL object module. 
Beware of mixing toolchains; many target platforms require that the HAL
and driver be built with the same toolchain (i.e. compiler, assembler,
and loader).  If you want to override the default toolchain specified in
the .inc file you can do that by editing the .inc file or by specifying
environment variables.

For example, the file for xscale-be-elf is:

#
# Compilation configuration for building big-endian XScale/arm-elf.
#

#
# Built with GNU cross-devel tools:
#
# PREFIX=/pub/gnu
# BINUTILS=binutils-2.14
# GCC=gcc-3.3.2
# target=arm-elf
#
# ${BINUTILS}/configure --target=$target --prefix=${PREFIX}
# ${GCC}/configure --target=$target   --prefix=${PREFIX} \
#	--enable-languages=c   --with-gnu-as --with-gnu-ld \
#	--with-newlib   --with-gxx-include-dir=${PREFIX}/$target/include
#
ifndef TOOLPREFIX
TOOLPREFIX=	/pub/gnu/bin/arm-elf-
endif
#
CC=	${TOOLPREFIX}gcc
LD=	${TOOLPREFIX}ld
STRIP=	${TOOLPREFIX}strip
OBJCOPY=${TOOLPREFIX}objcopy
NM=	${TOOLPREFIX}nm

LDOPTS=	-EB
COPTS+=	-DAH_BYTE_ORDER=AH_BIG_ENDIAN
COPTS+= -march=armv4 -mbig-endian -fno-strict-aliasing -fno-common -mapcs-32 \
	-mtune=xscale  -mshort-load-bytes -msoft-float

The first set of definitions specify the location and name of the
programs used to build the software.  The rest of the file defines
the compilation options for the target platform.  The latter should
usually not be changed because they were the options used to build
the binary HAL module, but TOOLPREFIX is unlikely to be right for
your system and you will want to change it; e.g.

trouble% export TOOLPREFIX=/usr/local/bin/arm-elf-

to use programs installed in /usr/local/bin.  Note that mixing different
versions of the GNU tools may not work.  The .inc file for each target
platform specifies the exact toolchains used, including where they
were obtained (if pre-built).

The build system is designed to support cross-building without any
modification to the distribution files.  If you cannot do what you
need by setting environment variables please send patches to show
where things failed to do the right thing.


Building the software will generate numerous loadable modules:

Linux 2.6
    ath/ath_pci.ko (Atheros driver for PCI/Cardbus devices),
    ath_hal/ath_hal.ko (Atheros HAL), and
    net80211/wlan.ko (802.11 support layer)
    net80211/wlan_wep.ko (WEP cipher support)
    net80211/wlan_tkip.ko (TKIP cipher support)
    net80211/wlan_ccmp.ko (AES-CCMP cipher support)
    net80211/wlan_xauth.ko (external authenticator)
    net80211/wlan_auth.ko (802.1x authenticator)
    net80211/wlan_radius.ko (RADIUS client for 802.1x authenticator)
    net80211/wlan_acl.ko (MAC ACL support for AP operation)

    and, depending on the rate control algorithm you choose (see above),
    one of these:

    ath_rate/onoe/ath_rate_onoe.ko (ONOE rate control)
    ath_rate/amrr/ath_rate_amrr.ko (AMRR rate control)
    ath_rate/sample/ath_rate_sample.ko (SAMPLE rate control)


Linux 2.4
    ath/ath_pci.o (Atheros driver for PCI/Cardbus devices),
    ath_hal/ath_hal.o (Atheros HAL), and
    net80211/wlan.o (802.11 support layer)
    net80211/wlan_wep.o (WEP cipher support)
    net80211/wlan_tkip.o (TKIP cipher support)
    net80211/wlan_ccmp.o (AES-CCMP cipher support)
    net80211/wlan_xauth.o (external authenticator)
    net80211/wlan_auth.o (802.1x authenticator)
    net80211/wlan_radius.o (RADIUS client for 802.1x authenticator)
    net80211/wlan_acl.o (MAC ACL support for AP operation)

    and, depending on the rate control algorithm you choose (see above),
    one of these:

    ath_rate/onoe/ath_rate_onoe.o (ONOE rate control)
    ath_rate/amrr/ath_rate_amrr.o (AMRR rate control)
    ath_rate/sample/ath_rate_sample.o (SAMPLE rate control)


The first three files must be loaded either manually or by the
system, e.g. through the hotplug or card manager support.  The
remaining modules are loaded by the wlan module as needed. Typically
modules are automatically loaded via dependencies, so after doing a
make install you only need to do:

    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

To see available parameters type:

    modinfo ath_pci


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.org/
