[yocto] One kernel tree, two BSP layers, two defconfigs. How to pickup the right one based on MACHINE value?

[Daniel.]

Hmmm that seems to fit as a glove to me, is that possible on Daisy?

Regards,
- dhs

2015-12-01 17:30 GMT-02:00 Paul Eggleton <paul.eggleton at linux.intel.com>:
> On Tue, 01 Dec 2015 11:27:19 Daniel. wrote:
>> Hi Saul, thanks for your reply
>>
>> 2015-11-30 21:29 GMT-02:00 Saul Wold <saul.wold at intel.com>:
>> > On Mon, 2015-11-30 at 17:25 -0200, Daniel. wrote:
>> >> Hi,
>> >>
>> >> I have one kernel tree where I keep all my modules in-tree. Inside
>> >> kernel I have two FOO_defconfig and BAR_defconfig which are
>> >> configurations for FOO-board and BAR-board. On Yocto I have
>> >> core-layer, FOO-bsp layer and BAR-bsp layer. At core-layer I have
>> >> linux-custom.bb file which has the URI for kernel tree with a dummy
>> >> defconfig. At FOO-bsp and BAR-bsp a have a .bbappend that adds a
>> >> folder with the right defconfig for each board.
>> >>
>> >> My doubt is: I have two .bbappends, on two distinct layers being
>> >> applied at same time? Both layers are pointed at
>> >> build/conf/bblayers.conf.
>> >
>> > So you are including both your BSP Layers in the bblayers, that will
>> > probably cause problems based on your description above.
>> >
>> > Another option is to look at using overrides and have 1 layer that
>> > supports both boards if they are similar and share other items.
>> >
>> >> How can I have sure to pick up the right defconfig at build time?
>> >>
>> >> I've tried to delete core-layer and have two kernel recipes with
>> >> distinct names, but Yocto complains about two recipes being selected
>> >> at same time for build (because of virtual/kernel feature or
>> >> something
>> >> alike). So I want to keep one kernel recipe and select the right
>> >> defconfig based on MACHINE value.
>> >
>> > You can use PREFERRED_PROVIDER_virtual/kernel to have multiple
>> > alternate kernel present and set it in your <machine>.conf to select
>> > the kernel you want.
>> >
>> > If your kernel recipe does not inherit kernel.bbclass you will need to
>> > set PROVIDES
>> >
>> > You should also be sure to set COMPATIBLE_MACHINE for each machine
>> >
>> >> Both defconfig are present on arch/arm/configs. Can I overwrite
>> >> do_config()? Is that safe? About the .bbappends: Should be two
>> >> .bbappends on same .bb file be avoided?
>> >
>> > You can use a do_config_prepend() to deal with moving the correct
>> > defconfig.
>>
>> Yeah I'm doing that. As you suggested I removed the .bbappend files and
>> have one recipe that support both machines, the config prepend looks
>> like this:
>>
>> do_configure_prepend() {
>>     case "${MACHINE}" in
>>         enlace-imx6)
>>         bbnote "Using csi_enlace_imx6_defconfig"
>>         cp -v ${S}/arch/arm/configs/csi_enlace_imx6_defconfig ${S}/defconfig
>> ;;
>>     pharosserver-imx6)
>>             bbnote "Using csi_pharosserver_imx6_defconfig"
>>         cp -v ${S}/arch/arm/configs/csi_pharosserver_imx6_defconfig
>> ${S}/defconfig
>>         ;;
>>     esac
>> }
>
> We do already have functionality that avoids the need for custom scripting
> like this.
>
> Unless you really need the defconfigs in-tree, the typical way to achieve this
> is to add "file://defconfig" to SRC_URI, then have defconfig files for each of the
> machines under subdirectories named the same as the machine. So your directory
> structure would look like this:
>
> .../recipes-linux/linux-something/linux-something_versionnumber.bb
> .../recipes-linux/linux-something/linux-something/enlace-imx6/defconfig
> .../recipes-linux/linux-something/linux-something/pharosserver-imx6/defconfig
>
> Cheers,
> Paul
>
> --
>
> Paul Eggleton
> Intel Open Source Technology Centre



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