Yocto Customizing the Linux kernel

VAR-SOM-MX6 - Customizing the Linux kernel

Choose one of the following three methods to customize the Linux kernel and build it using Yocto:

Add your own patches on top of our source code

Using this method Yocto will take the source code from our default remote repository, and apply your patches to it before building it:

Get the source code by cloning our repository:

$ cd ~/var-fslc-yocto
$ mkdir -p local_repos
$ cd local_repos
$ git clone https://github.com/varigit/linux-2.6-imx.git
$ cd linux-2.6-imx
$ git checkout imx-rel_imx_4.1.15_2.0.0_ga-var02

Make your changes in the source code and create a patch:
You can use either diff or patch file types.
For example:

$ cd ~/var-fslc-yocto/local_repos/linux-2.6-imx
$ gedit arch/arm/boot/dts/imx6qdl-var-som.dtsi
edit and save

$ git diff > imx6qdl-var-som_device_tree_changes.diff

Update the recipes to use your patch:
Copy your patch:

$ cd ~/var-fslc-yocto/sources/meta-variscite-fslc/recipes-kernel/linux/
$ mkdir -p files
$ cp ~/var-fslc-yocto/local_repos/linux-2.6-imx/imx6qdl-var-som_device_tree_changes.diff  files/

Create a linux-variscite_4.1.15.bbappend file:

$ gedit linux-variscite_4.1.15.bbappend

and append the following line to it:

SRC_URI += "file://imx6qdl-var-som_device_tree_changes.diff"

Use a local repository

Using this method Yocto will take the kernel source from a local repository instead of our remote ones on github:

Get the source code by cloning our repository:

$ cd ~/var-fslc-yocto
$ mkdir -p local_repos
$ cd local_repos
$ git clone https://github.com/varigit/linux-2.6-imx.git
$ cd linux-2.6-imx
$ git checkout imx-rel_imx_4.1.15_2.0.0_ga-var02

Make your changes in the source code and commit them:
After making changes in the source code you need to commit them.
For example:

$ cd ~/var-fslc-yocto/local_repos/linux-2.6-imx
$ gedit arch/arm/boot/dts/imx6qdl-var-som.dtsi
edit and save

$ git commit -a -m "imx6qdl-var-som device tree changes"

To list all of the commits:
$ git log

Get the latest commit id:
$ git rev-parse HEAD

Update the recipes to use the local repository instead of the default one:

$ cd ~/var-fslc-yocto/sources/meta-variscite-fslc/recipes-kernel/linux/

Create a linux-variscite_4.1.15.bbappend file:

$ gedit linux-variscite_4.1.15.bbappend

and append the following lines to it (see the previous section for listing the commits or getting the latest commit id):

KERNEL_SRC = "git://${BSPDIR}/local_repos/linux-2.6-imx;protocol=file"
SRCBRANCH = "imx-rel_imx_4.1.15_2.0.0_ga-var02" (or your own created branch)
SRCREV = "The commit id you'd like to use"

For the SRCREV value you can also use "${AUTOREV}" during development to get the latest commit of the branch

Use your own remote repository on github

Using this method Yocto will take the source code from your own remote repository on github:

Create your own github account and upload your proprietary kernel to a new repository:
For example, you can fork our repository to your own account by visiting the following link and clicking on "Fork" at the top right of the screen.
Alternatively, you can clone our repository to your local machine, and push it later to your own account.

https://github.com/varigit/linux-2.6-imx/tree/imx-rel_imx_4.1.15_2.0.0_ga-var02

Update the recipes to use your remote repository instead of the default one:

$ cd ~/var-fslc-yocto/sources/meta-variscite-fslc/recipes-kernel/linux/

Create a linux-variscite_4.1.15.bbappend file:

$ gedit linux-variscite_4.1.15.bbappend

and append the following lines to it (see the previous section for listing the commits or getting the latest commit id):

KERNEL_SRC = "git://github.com/your_account/linux-2.6-imx.git;protocol=git"
SRCBRANCH = "imx-rel_imx_4.1.15_2.0.0_ga-var02" (or your own created branch)
SRCREV = "The commit id you'd like to use"

For the SRCREV value you can also use "${AUTOREV}" during development to get the latest commit of the branch