[yocto] [meta-raspberrypi] how to customize kernel config?

[Alex J Lennon]

On 12/06/2014 07:48, Jonatan Magnusson wrote:
> Hi
>
> I’m trying to use the meta-raspberrypi BSP with Yocto (1.6, Daisy).
>
> It works great, except I have no idea how to use a custom kernel config!
>
> I have a custom kernel recipe that bbappends to the meta-raspberrypi kernel recipe.
>
> I’ve tried using defconfig as well as configuration fragments, but neither work.
>
> I’ve also tried using the kernel_configure_variable function, and that almost works, except if I try to disable an option that is enabled earlier in the the config file, the option is still enabled since kernel_configure_variable only appends to the config file.
>
> Example:
>
> do_configure_append() {
>   kernel_configure_variable SPI_SPIDEV n
> }
>
> So I wonder: how is this supposed to work?
>

I don't think the RPi kernel recipe supports the linux-yocto include and
thus kernel fragments, which would be the preferred way to do things.

(At least if it does I didn't manage to get it working - I am
considering trying to add support for this in).

In the meantime to create a configuration I

bitbake -c menuconfig virtual/kernel

Edit the settings and save the resulting .config file

Then if you go to

bitbake -c devshell virtual/kernel

You can copy the .config file out of there to your source tree

Then the recipe I use to build with that configuration is something like
this, with my_defconfig in a patch
containing linux-raspberrypi folder set for searching with the path prepend,

FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"

KERNEL_DEFCONFIG = "my_defconfig"

SRC_URI += "file://rov_defconfig"

do_configure_prepend() {
        cp ${WORKDIR}/my_defconfig ${S}/arch/arm/configs
}

Regards,

Alex