On 2/21/20 10:14 AM, Alexandre Torgue wrote: > (with title it's better ;) > > Hi, > > The goal of this series is to add device tree build information in dtb. > This information can be dtb build date, where devicetree files come from, > who built the dtb ... Actually, same kind of information that you can find > in the Linux banner which is printout during kernel boot. Having the same > kind of information for device tree is useful for debugging and maintenance. > > A file (dtb-build.txt) containing a string with build information (e.g., >>From Linux 5.5.0-rc1 by alex the Mon Jan 13 18:25:38 CET 2020) is generated by > "gen_dtb_build_info.sh" script. > > This file has to be included manually in each dts file that would like to use > this build information. In the RFC series, you said: "I gonna prepare a V2 with David proposition (to use overlay format) by keeping in mind not to modify existing dts(i) files." https://lore.kernel.org/linux-devicetree/9d83a36c-78c5-3452-bb48-209d68c46038@xxxxxx/ But here in v2 instead requires including dtb-build.txt. This would require modifying every single main .dts file to get the build info. I would prefer the method that Ian and David came up with (sorry, no lore link, it did not go to lkml). Extract from David's email: Date: Tue, 21 Jan 2020 13:05:25 +1100 From: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx> Subject: Re: [RFC PATCH 1/3] dtc: Add dtb build information option > Given that dts files are run through the C preprocessor before being > fed to dtc, the build script could use the '-include' flag to force- > include a fragment containing generated build info without any need to > modify existing dts files. Uh... maybe. -include will essentially prepend the forced file, which is a bit awkward for our purposes. It means that the prepended file would need the /dts-v1/ tag, and we couldn't have it in the main files which would be a bit confusing. I think it would also cause problems with any /memreserve/ tags and means that the main tree could in theory overwrite the build information which we don't necessarily want. I guess we could build things the other way around: have the main .dts file specified with -include and have the dts on the dtc commandline be a fixed one with the build information. It'd be a little weird, though. -Frank > > of/fdt.c is modified to printout "build-info" property during Kernel boot and > scripts/Makefile.lib is modified to call "gen_dtb_build_info.sh" script. > > Patch 1 & 2 script and of/fdt.c updates > Patch 3 is an example of use in stm32mp157c-dk2.dts file. > Patch 4 is a tentative to make it automatic (not yet 100% functional). > > regards > Alex > > Changes since v1; > - Remove modification in dtc (no more -B option) > - Generate a file containing build info which is directly included in dts > file. > > > Regards > Alex > > Alexandre Torgue (4): > scripts: Add script to generate dtb build information > of: fdt: print dtb build information > ARM: dts: stm32: Add dtb build information entry for stm32mp157c-dk2 > script: make automatic dtb build info generation > > arch/arm/boot/dts/stm32mp157c-dk2.dts | 1 + > drivers/of/fdt.c | 9 +++++++++ > scripts/Makefile.lib | 3 +++ > scripts/gen_dtb_build_info.sh | 12 ++++++++++++ > 4 files changed, 25 insertions(+) > create mode 100755 scripts/gen_dtb_build_info.sh >
