On Mon, Jan 06, 2025 at 02:55:22PM +0100, Christophe Leroy wrote: > Le 02/01/2025 à 19:31, J. Neuschäfer via B4 Relay a écrit : > > [Vous ne recevez pas souvent de courriers de devnull+j.ne.posteo.net@xxxxxxxxxx. Découvrez pourquoi ceci est important à https://aka.ms/LearnAboutSenderIdentification ] > > > > From: "J. Neuschäfer" <j.ne@xxxxxxxxxx> > > > > In order to produce useful FIT images, the kernel needs to know which > > devicetrees to build. To that end, follow the same approach as other > > architectures, and enable devicetrees per platform. > > Why do you need that ? The FIT infrastructure uses the dtbs-y variable and the dtbs-list file built from it in order to obtain a list of DTBs to include. Having roughly the right DTBs included by setting a simple config option to =y is pretty convenient. > Why not just use CONFIG_EXTRA_TARGETS for that ? To be honest, I didn't know about CONFIG_EXTRA_TARGETS until now. But I also don't quite understand it: () Additional default image types I don't need an additional image type. I want additional device trees, if anything. One thing I specifically wanted to avoid by using FIT is having to add more per-board bootwrapper logic to arch/powerpc/boot/Makefile. > > > > Signed-off-by: J. Neuschäfer <j.ne@xxxxxxxxxx> > > --- > > > > I've only enabled MPC831x devicetrees, because that's the hardware I have. > > --- > > arch/powerpc/boot/dts/Makefile | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/arch/powerpc/boot/dts/Makefile b/arch/powerpc/boot/dts/Makefile > > index 0cd0d8558b475cfe342f36f4b78240ef88dd2e37..6aee895d5baaa2c978d4b1c82a6d198d9e166ea2 100644 > > --- a/arch/powerpc/boot/dts/Makefile > > +++ b/arch/powerpc/boot/dts/Makefile > > @@ -3,3 +3,8 @@ > > subdir-y += fsl > > > > dtb-$(CONFIG_OF_ALL_DTBS) := $(patsubst $(src)/%.dts,%.dtb, $(wildcard $(src)/*.dts)) > > + > > +dtb-$(CONFIG_MPC831x) += \ > > + kmeter1.dtb \ > > + mpc8313erdb.dtb \ > > + mpc8315erdb.dtb > > How will it know which one of the three to put in the FIT image ? > Or do you want all three in the FIT image ? It includes all of them, which is an acceptable outcome. > In that case how do you select which one to use at boot ? The bootloader (most likely U-Boot) is expected to know the compatible string of the board and select the right devicetree based on it. Best regards, J. Neuschäfer
