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

[Paul Eggleton]

Yes that's been possible for quite a long time now (possibly going back to OE-
classic).

Cheers,
Paul

On Tue, 01 Dec 2015 17:48:26 Daniel. wrote:
> 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/defcon
> > fig
> > 
> > Cheers,
> > Paul
> > 
> > --
> > 
> > Paul Eggleton
> > Intel Open Source Technology Centre

-- 

Paul Eggleton
Intel Open Source Technology Centre