Building Linux kernel (XUELK)

Info Box Applies to AXEL ULite Applies to SBC Lynx

History

Version	Date	XUELK version	Notes
1.0.0	August 2016	XUELK 1.0.0
1.1.3	March 2017	XUELK 1.1.3
1.2.0	May 2017	XUELK 1.2.0	Update for new XUELK release
2.0.1	Sep 2017	XUELK 2.0.1	Update for new XUELK release
2.0.2	Feb 2018	XUELK 2.0.1	Add kernel modules documentation

Quick reference

Repository Information

URL	git@git.dave.eu:lynx/linux-2.6-imx.git
stable branch	lynx
stable tag	xuelk-2.0.1

Build Information

defconfig	imx_v7_lynx_defconfig
Kernel binary	UIMAGE_LOADADDR=0x80008000 uImage
Device trees	Platform	SOM ConfigID	CB ConfigID	DTB
	SBC Lynx	0x00000008	0x0000000E	imx6ul-lynx.dtb
	SBC Lynx	0x0000000C	N/A	imx6ul-lynx-som000c.dtb
	SBC Lynx	0x00000013	0x0000002D 0x0000002E 0x0000002F 0x00000030	imx6ul-lynx-som0013-cb002d.dtb imx6ul-lynx-som0013-cb002e.dtb imx6ul-lynx-som0013-cb002f.dtb imx6ul-lynx-som0013-cb0030.dtb
	Axel ULite	0x0000000B 0x00000014	0x00000010	imx6ul-axelulite-cb0010.dtb

Detailed Instructions

It is assumed that the development environment has been set up properly as described here.

• start the Linux development VM and login into the system
• open a terminal window and cd into Linux kernel source code

cd lynx/linux/

• in case of needs you can update your local repository with the following git command

git pull

• configure the build environment

source ~/env.sh

• to build the binaries run the following commands:

make imx_v7_lynx_defconfig
make UIMAGE_LOADADDR=0x80008000 uImage imx6ul-lynx-som000c.dtb imx6ul-lynx-som0013-cb002f.dtb imx6ul-axelulite-cb0010.dtb
make modules

The first command selects the default XUELK configuration, the second builds the kernel binary image with the required u-boot header and the kernel device tree, while the last command build kernel modules (if present in kernel configuration).

Default Linux kernel configuration can be changed by using the standard menuconfig, xconfig, or gconfig make target. Subsequent builds just require uImage make target to update the binary image. Once the build process is complete, the kernel binary image is stored into the arch/arm/boot/uImage file. Both this file and the kernel device tree can be copied to the tftp root directory /tftpboot/lynx/ with the following commands:

cp arch/arm/boot/uImage /tftpboot/lynx/
cp arch/arm/boot/dts/*.dtb /tftpboot/lynx/

Usually kernel modules are installed with make modules_install command, but this install the modules into /lib/modules directory of you MVM, which is not what you want. A better way to deploy kernel modules while cross-compiling is

• generate a .tar.gz archive
• install this archive into the target root file system

User can create such an archive for example using the following commands

mkdir modules-install
make INSTALL_MOD_PATH=modules-install modules_install

cd modules-install && tar cvzf ../modules.tar.gz . && cd ..

Now copy modules.tar.gz into the target root file system and install them as root with the following command

tar xvzf modules.tar.gz -C /