imdbere / Ath9k

Ath9k Linux kernel driver to export CSI information for kernels v5.4+

Ath9k CSI Driver for Qualcomm Atheros AR93XX chips

Credits

This work is based off of the work by WANDS. Cheers!

About

This is modified version of the mainline Linux kernel Ath9k Qualcomm wireless driver. Incorporating changes similar to those found here, only for a more relevant kernel version.

Building

I recommend not using an old distribution such as Ubuntu 14 etc as Ubuntu itself struggles to keep up to date, but an outdated Ubuntu version are hopelessly behind and will probably have problems with a modern kernel on ancient gcc versions. eg. Ubuntu 14 uses gcc 4.8 which will give a lot of errors with a 5.4+ kernel.

Prerequisites

Standard Linux kernel prerequisites are required

Arch

sudo pacman -S base-devel ncurses flex bison openssl libelf

Ubuntu

sudo apt-get install build-essential libncurses-dev bison flex libssl-dev libelf-dev

Source code

The driver can be built in the kernel source tree or out of the kernel source tree. Below both methods are described.

Either way you will need a copy of the Linux kernel.

git clone https://github.com/torvalds/linux
cd linux

In tree

To build the module as part of the kernel you simply need to place the modified driver into the kernel source tree and perform a standard kernel build.

rm drivers/net/wireless/ath/ath9k/*
cp -r $(THIS REPO)/* drivers/net/wireless/ath/ath9k/

or run the patch to patch the changes into the ath9k folder. Please note this should be done from the directory in which the linux folder is.

patch -sf -p0 < patches/ath9k.patch

Config

You will need to prepare the kernel to run on the target system, this is done through a .config file and it can be extracted from your existing system.

Arch

zcat /proc/config.gz > .config

Ubuntu

cp /boot/config-$(uname -r) .config

You will then need to run menuconfig or try olddefconfig to synchronize the configs.

make menuconfig

or

make olddefconfig

Make

You must then perform a normal kernel build and a kernel and module install

sudo make -j$(nproc) && sudo make modules_install -j$(nproc) && sudo make install -j$(nproc)

or to build just the ath9k driver

sudo make -j$(nproc) drivers/net/wireless/ath/ath9k/

reboot and check if your new kernel is installed, otherwise continue below.

Booting from kernel (Not always necessary)

My test machines run Ubuntu so I will detail the process for an Ubuntu machine. Arch machines are dependent on the bootloader you have chosen and, as such, harder to detail. This example below is for a 5.4 kernel.

Update your initframfs and your grub.

update-initramfs -c -k 5.4
update-grub

Set the kernel as the default for grub by modifying /etc/default/grub

sudo vim /etc/default/grub

Then add the following to the GRUB_DEAFULT line so that it looks like the following

GRUB_DEAFULT="Advanced options for Ubuntu>Ubuntu, with Linux 5.4"

finally reboot and check the new kernel is being used with uname -r

Out of tree build

An out of tree build means that you simply pass the kernel tree into make with the -C option. This is done using the KDIR variable, set it appropriately.

As the Ath9k driver has the include structure of a potato it is challenging to build it out of tree as the driver has absolute include paths that traverse higher than the ath9k driver. One solution is to build the entire ath folder or to patch the ath folder to fix up the include fro the ath9k driver. Sorry other ath driver but I have better things to do with my time.

export KDIR=$HOME/linux # Assuming linux was cloned into home
sudo make -C $KDIR M=$KDIR/drivers/net/wireless/ath modules

or if you want to directly install the built module

sudo make -C $KDIR -M $KDIR/drivers/net/wireless/ath modules_install

and reboot.

Module install script

here

An old build script I made when testing the WANDS Ubuntu 14 implementation. It should give an outline of the manual process, although the kernel build system should handle this automatically as detailed above.

Travis CI

The Travis CI config (.travis.yml) also provides the steps necessary.