DESK-MX6UL-L/Development/Building Linux kernel

History
Version	Issue Date	Notes
X.Y.Z	Month Year	TBD
[TBD_link X.Y.Z]	Month Year	TBD

Building Linux

Quick reference

Repository Information

URL	git@git.dave.eu:desk-mx-l/linux-TBD.git
stable branch	desk-mx-l
stable tag	desk-mx-l-1.x.x

Build Information

defconfig	<defconfig>
Kernel binary	UIMAGE_LOADADDR=<loadaddr> uImage
Device trees	Platform	DTB
	SBC	<carrier>.dtb
	EVB	<carrier>.dtb

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 {{{kit-repo}}}/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

• enter the source tree directory and run the following commands:

make imx_v7_{{{kit-repo}}}_defconfig
make  UIMAGE_LOADADDR=''<loadaddr>'' uImage ''<carrier>''.dtb

NOTE: this is the default configuration suitable for latest target.

The former command selects the default DESK-MX6UL-L configuration, while the latter builds the kernel binary image with the required u-boot header and the kernel device tree.

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/desk-mx-l/ with the following commands:

cp arch/arm/boot/uImage /tftpboot/{{{kit-repo}}}/
cp arch/arm/boot/dts/*.dtb /tftpboot/{{{kit-repo}}}/

Usually, kernel modules are installed with make modules_install command, but this method installs the modules into the /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 /

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