From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Glass Date: Wed, 4 Mar 2020 10:51:27 -0700 Subject: [PATCH 1/2] Makefile: Add environment variable DEVICE_TREE to header In-Reply-To: References: <65fe3fb4b7f682b4a292b261f0140b1f89f4610e.1582041753.git.michal.simek@xilinx.com> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Michal, On Tue, 3 Mar 2020 at 23:44, Michal Simek wrote: > > On 04. 03. 20 3:47, Simon Glass wrote: > > Hi Michal, > > > > On Mon, 2 Mar 2020 at 23:52, Michal Simek wrote: > >> > >> On 02. 03. 20 20:47, Simon Glass wrote: > >>> Hi Michal, > >>> > >>> On Fri, 28 Feb 2020 at 04:03, Michal Simek wrote: > >>>> > >>>> On 26. 02. 20 16:33, Simon Glass wrote: > >>>>> Hi Michal, > >>>>> > >>>>> On Tue, 18 Feb 2020 at 09:02, Michal Simek wrote: > >>>>>> > >>>>>> Users have option to overwrite default device tree > >>>>>> (CONFIG_DEFAULT_DEVICE_TREE) via environment variable DEVICE_TREE. > >>>>>> > >>>>>> Feature has been added long time ago by commit 74de8c9a1672 > >>>>>> ("dts/Makefile: Build the user specified dts") for a little bit different > >>>>>> reason. > >>>>>> > >>>>>> But this variable can be also used for different purpose like choosing > >>>>>> proper configuration from FIT image in SPL. > >>>>>> And this is the functionality I would like to use on Xilinx Zynq devices > >>>>>> that current u-boot.img can be composed in the same way based on OF_LIST > >>>>>> and different configuration is taken based on platform specific SPL. > >>>>>> SPL requires low level ps7_init_gpl configuration that's why different > >>>>>> boards require different SPL with fixed board_fit_config_name_match(). > >>>>>> > >>>>>> Signed-off-by: Michal Simek > >>>>>> --- > >>>>>> > >>>>>> I have done it in this way but maybe there is any smarter way how this can > >>>>>> be done. Also macro name can change if you want. > >>>>> > >>>>> Can you please add a bit of documentation to doc/README.fdt-control ? > >>>> > >>>> This feature is cover by documentation in this file already. What > >>>> exactly do you think that should be added? > >>>> > >>> > >>> Then I suppose I am confused as to what this patch does. I thought it > >>> was allowing U-Boot to pass the DT to Linux, which wasn't previously > >>> supported? > >> > >> Just a note this is also not supported and would be good to have support > >> for it. > >> > >> The patch is putting device tree name as macro to header and I am using > >> this value just in zynq SPL to choose proper dtb file from u-boot.img. > >> > >> On ZynqMP generic platform I am using mkimage_fit_atf.sh script to > >> automatically fill default configuration. > >> https://gitlab.denx.de/u-boot/u-boot/blob/master/arch/arm/mach-zynqmp/mkimage_fit_atf.sh#L94 > >> And I didn't want to create different u-boot.img/itb for Zynq that's why > >> SPL has device tree built it directly in SPL. > >> > >> As I said maybe there is smarter way how to do it but this was the one I > >> used. > >> In our case SPL another way could be to put filename from ps7_init_* > >> files and save it as variable and use it. > > > > OK I see. So are you using OF_CONTROL for SPL? > > Yes. OK ta. Reviewed-by: Simon Glass Regards, Simon