TS-4900 Kernel Compile Guide

From Technologic Systems Manuals

To add additional driver support, reduce the size of our stock kernel kernel, or to write custom kernel drivers the kernel can be compiled from our sources. The following steps walk through the kernel build process; they are compatible with most of our Linux distributions.

This device has multiple kernels released and available in our git repository:

Newer kernels are released on the linux-tsimx repository:

  • embeddedarm/linux-tsimx
  • The "ts-imx_4.9.11_1.0.0_ga" branch is the only one that should be used with our i.MX6 series.

For legacy kernels:

  • embeddedarm/linux-3.10.17-imx6
  • The "master" branch is 3.10.17 and is largely outdated and replaced with later kernels. This is used with the old Yocto Dora builds.
  • The "imx_3.10.53_1.1.0_ga" kernel is a stable branch. Use this with Yocto Dizzy, Fido, or compatible with Debian Jessie.
  • The "imx_3.14.52_1.1.0_ga" branch is compatible with Yocto Jethro, and Debian.
  • The "imx_4.1.15_1.0.0_ga" branch is compatible with Yocto Jethro, Yocto Morty and Debian. Includes recent fixes not in older branches. This is recommended for most users.

The kernel can be rebuilt by cross compiling from an x86 or x86_64 Linux workstation. Our stock kernels are built with the toolchains built by Yocto. The appropriate cross toolchain for your Linux workstation can be downloaded here:

Note: Older kernels will require older toolchains. For older Yocto kernels use a matching Yocto toolchain. For Debian, the latest toolchain and kernel is recommended.
chmod a+x poky*.sh
sudo ./poky*.sh

This will ask for the install directory for the toolchain. A custom location can be chosen, however the following instructions will assume the default installation location.

This process will also require several applications for the install/build process. These can be installed on an Ubuntu/Debian workstation with the following command:

sudo apt-get install git build-essential lzop u-boot-tools libncursesw5-dev fakeroot

Once those are installed:

git clone https://github.com/embeddedarm/linux-tsimx.git -b ts-imx_4.9.11_1.0.0_ga linux-tsimx6 --depth 1

# For legacy kernels instead:
# git clone https://github.com/embeddedarm/linux-3.10.17-imx6.git -b imx_4.1.15_1.0.0_ga linux-tsimx6 --depth 1
# If it is already cloned, the "git pull" command will download and merge the latest changes

# For WiFi support, download qcacld-2.0:
# This is only compatible with 4.1.15 or 4.9.11 kernels
git clone https://github.com/embeddedarm/qcacld-2.0.git -b caf-wlan/CNSS.LEA.NRT_3.1

cd linux-tsimx6
# These export commands must be run every time before any make commands
export ARCH=arm
# For 64-bit
export CROSS_COMPILE=/opt/poky/2.2.2/sysroots/x86_64-pokysdk-linux/usr/bin/arm-poky-linux-gnueabi/arm-poky-linux-gnueabi-
# For 32-bit
#export CROSS_COMPILE=/opt/poky/2.2.2/sysroots/i686-pokysdk-linux/usr/bin/arm-poky-linux-gnueabi/arm-poky-linux-gnueabi-
export LOADADDR=0x10008000
export TEMPDIR=$(mktemp -d)

make ts4900_defconfig

## Make any changes in "make menuconfig" or driver modifications, then compile
make -j8 all uImage zImage

mkdir "$TEMPDIR"/boot/
cp arch/arm/boot/uImage  "$TEMPDIR"/boot/uImage
cp arch/arm/boot/zImage  "$TEMPDIR"/boot/zImage
cp arch/arm/boot/dts/imx6*-ts*.dtb "$TEMPDIR"/boot/
INSTALL_MOD_PATH="$TEMPDIR" make modules_install
make headers_install INSTALL_HDR_PATH="$TEMPDIR"

# Compile wifi driver:
cd ../qcacld-2.0/
export KERNEL_SRC="../linux-tsimx6/"
make clean
CONFIG_CLD_HL_SDIO_CORE=y make -j8
INSTALL_MOD_PATH="$TEMPDIR" make modules_install 

fakeroot sh -c "chmod 755 $TEMPDIR;
	chown -R root:root $TEMPDIR;
	tar cjvf kernel.tar.bz2 -C $TEMPDIR .;
	rm -rvf $TEMPDIR"

This will generate "kernel.tar.bz2" which contains the kernel and necessary modules. It can be installed to the device by copying it to a running unit and executing:

# Only run this on a device! Not on a workstation!
tar -xf kernel.tar.bz2 -C /

This can also be extracted over existing images from a workstation, or removable media like SD cards. For example, assuming the SD card on a workstation is "/dev/sdc":

mkdir /mnt/sd/
mount /dev/sdc1 /mnt/sd/
tar -xf kernel.tar.bz2 -C /mnt/sd/
umount /mnt/sd/

Change Kernel Splash Screen

The kernel splashscreen allow for a 224 color image, up to the full screen resolution. For the fastest boot speed, it should be kept as small as possible. The image will be centered around a black background.

To convert an image, for example, "mylogo.png":

convert mylogo.png mylogo.ppm
ppmquant 224 mylogo.ppm > mylogo-224.ppm
pnmnoraw mylogo-224.ppm > logo_user_clut224.ppm
cp logo_user_clut224.ppm <kernel build sources>/drivers/video/logo/

Recompile the kernel following the guide in the previous section to have the splashscreen appear on all future boots.

Add to the kernel cmdline in U-Boot, "logo.nologo" in order to completely disable the splash screen.