[PATCH v6 00/25] fdt: Make OF_BOARD a boolean option
François Ozog
francois.ozog at linaro.org
Thu Dec 2 17:59:00 CET 2021
Hi Simon
Le jeu. 2 déc. 2021 à 17:40, Simon Glass <sjg at chromium.org> a écrit :
> Hi François,
>
> On Thu, 2 Dec 2021 at 09:34, François Ozog <francois.ozog at linaro.org>
> wrote:
> >
> > Hi Simon
> >
> > Le jeu. 2 déc. 2021 à 17:00, Simon Glass <sjg at chromium.org> a écrit :
> >>
> >> With Ilias' efforts we have dropped OF_PRIOR_STAGE and OF_HOSTFILE so
> >> there are only three ways to obtain a devicetree:
> >>
> >> - OF_SEPARATE - the normal way, where the devicetree is built and
> >> appended to U-Boot
> >> - OF_EMBED - for development purposes, the devicetree is embedded in
> >> the ELF file (also used for EFI)
> >> - OF_BOARD - the board figures it out on its own
> >>
> >> The last one is currently set up so that no devicetree is needed at all
> >> in the U-Boot tree. Most boards do provide one, but some don't. Some
> >> don't even provide instructions on how to boot on the board.
> >>
> >> The problems with this approach are documented in another patch in this
> >> series: "doc: Add documentation about devicetree usage"
> >>
> >> In practice, OF_BOARD is not really distinct from OF_SEPARATE. Any board
> >> can obtain its devicetree at runtime, even it is has a devicetree built
> >> in U-Boot. This is because U-Boot may be a second-stage bootloader and
> its
> >> caller may have a better idea about the hardware available in the
> machine.
> >> This is the case with a few QEMU boards, for example.
> >>
> >> So it makes no sense to have OF_BOARD as a 'choice'. It should be an
> >> option, available with either OF_SEPARATE or OF_EMBED.
> >>
> >> This series makes this change, adding various missing devicetree files
> >> (and placeholders) to make the build work.
> >>
> >> Note: If board maintainers are able to add their own patch to add the
> >> files, some patches in this series can be dropped.
> >>
> >> It also provides a few qemu clean-ups discovered along the way. The
> >> qemu-riscv64_spl problem is fixed.
> >>
> >> [1]
> https://patchwork.ozlabs.org/project/uboot/patch/20210919215111.3830278-3-sjg@chromium.org/
> >>
> >> Changes in v6:
> >> - Fix description of OF_BOARD so it refers just to the current state
> >> - Explain that the 'two devicetrees' refers to two *control* devicetrees
> >> - Expand the commit message based on comments
> >> - Expand the commit message based on comments
> >
> > You haven’t addressed any concerns expressed on the mailing list.so I am
> not in favor of this new version either.
>
> Please see the change log. I have addressed everything except the
> fundamental disagreement we have.
>
> > If you make a version without « fake DTs » as you name them, there are
> good advances in the documentation and other areas that would be better in
> mainline….
> > If I am the only one thinking this way and the patch can be accepted, I
> would love there is a warning in capital letters at the top of the DTS fake
> files that explains the intent of this fake DT, the possible outcomes of
> not using the one provided by the platform and the right way of dealing
> with DTs for the platform.
>
> The word 'fake' applies to only three of the boards (highbank, bcm7xxx
> and octeontx),
Qemu is another one, and then you will have all SystemReady compliant
boards.
> where I could not even figure out where to get a
> devicetree. One might think this would be a significant problem!
>
> Anyway yes I can add a comment to all the files, but please try to ask
> for everything at once as there is a cost to continually reworking
> this series.
I proposed this as a last resort if I was the only one with concerns. But
sounds like I am not the only one strongly opinionated here.
Another trick would be to use a “.dts.doc” extension so that it is not
compiled unless someone is knowingly deciding to use the fake DT for debug
purposes (the warning message is still valid). (This is an effort to
advance on the good things of the patch)
>
>
> Regards,
> Simon
>
> >>
> >>
> >> Changes in v5:
> >> - Bring into the OF_BOARD series
> >> - Rebase to master and drop mention of OF_PRIOR_STAGE, since removed
> >> - Refer to the 'control' DTB in the first paragraph
> >> - Use QEMU instead of qemu
> >> - Merge RISC-V and ARM patches since they are similar
> >> - Add new patches to clean up fdtdec_setup() and surrounds
> >>
> >> Changes in v3:
> >> - Clarify the 'bug' refered to at the top
> >> - Reword 'This means that there' paragraph to explain U-Boot-specific
> things
> >> - Move to doc/develop/devicetree now that OF_CONTROL is in the docs
> >>
> >> Changes in v2:
> >> - Fix typos per Sean (thank you!) and a few others
> >> - Add a 'Use of U-Boot /config node' section
> >> - Drop mention of dm-verity since that actually uses the kernel cmdline
> >> - Explain that OF_BOARD will still work after these changes (in
> >> 'Once this bug is fixed...' paragraph)
> >> - Expand a bit on the reason why the 'Current situation' is bad
> >> - Clarify in a second place that Linux and U-Boot use the same
> devicetree
> >> in 'To be clear, while U-Boot...'
> >> - Expand on why we should have rules for other projects in
> >> 'Devicetree in another project'
> >> - Add a comment as to why devicetree in U-Boot is not 'bad design'
> >> - Reword 'in-tree U-Boot devicetree' to 'devicetree source in U-Boot'
> >> - Rewrite 'Devicetree generated on-the-fly in another project' to cover
> >> points raised on v1
> >> - Add 'Why does U-Boot have its nodes and properties?'
> >> - Add 'Why not have two devicetrees?'
> >>
> >> Simon Glass (25):
> >> doc: Add documentation about devicetree usage
> >> arm: qemu: Mention -nographic in the docs
> >> arm: riscv: qemu: Explain how to extract the generated dt
> >> arm: qemu: Add a devicetree file for qemu_arm
> >> arm: qemu: Add a devicetree file for qemu_arm64
> >> riscv: qemu: Add devicetree files for qemu_riscv32/64
> >> arm: rpi: Add a devicetree file for rpi_4
> >> arm: vexpress: Add a devicetree file for juno
> >> arm: xenguest_arm64: Add a fake devicetree file
> >> arm: octeontx: Add a fake devicetree file
> >> arm: xilinx_versal_virt: Add a devicetree file
> >> arm: bcm7xxx: Add a devicetree file
> >> arm: qemu-ppce500: Add a devicetree file
> >> arm: highbank: Add a fake devicetree file
> >> fdt: Make OF_BOARD a bool option
> >> Drop CONFIG_BINMAN_STANDALONE_FDT
> >> doc: Update info on devicetree update
> >> fdt: Move MULTI_DTB_FIT handling out of fdtdec_setup()
> >> fdt: Drop #ifdefs with MULTI_DTB_FIT
> >> fdt: Drop CONFIG_SPL_BUILD check in fdtdec_setup()
> >> fdt: Drop #ifdef around board_fdt_blob_setup()
> >> fdt: Use if() for fdtcontroladdr check
> >> fdt: Drop OF_CONTROL check in fdtdec_setup()
> >> fdt: Drop remaining preprocessor macros in fdtdec_setup()
> >> fdt: Don't call board_fdt_blob_setup() without OF_BOARD
> >>
> >> Makefile | 3 +-
> >> arch/arm/dts/Makefile | 20 +-
> >> arch/arm/dts/bcm2711-rpi-4-b.dts | 1958 ++++++++++++++++++++++++
> >> arch/arm/dts/bcm7xxx.dts | 15 +
> >> arch/arm/dts/highbank.dts | 14 +
> >> arch/arm/dts/juno-r2.dts | 1038 +++++++++++++
> >> arch/arm/dts/octeontx.dts | 14 +
> >> arch/arm/dts/qemu-arm.dts | 402 +++++
> >> arch/arm/dts/qemu-arm64.dts | 381 +++++
> >> arch/arm/dts/xenguest-arm64.dts | 15 +
> >> arch/arm/dts/xilinx-versal-virt.dts | 307 ++++
> >> arch/powerpc/dts/Makefile | 1 +
> >> arch/powerpc/dts/qemu-ppce500.dts | 264 ++++
> >> arch/riscv/dts/Makefile | 2 +-
> >> arch/riscv/dts/qemu-virt.dts | 8 -
> >> arch/riscv/dts/qemu-virt32.dts | 217 +++
> >> arch/riscv/dts/qemu-virt64.dts | 217 +++
> >> configs/bcm7260_defconfig | 1 +
> >> configs/bcm7445_defconfig | 1 +
> >> configs/highbank_defconfig | 2 +-
> >> configs/octeontx2_95xx_defconfig | 1 +
> >> configs/octeontx2_96xx_defconfig | 1 +
> >> configs/octeontx_81xx_defconfig | 1 +
> >> configs/octeontx_83xx_defconfig | 1 +
> >> configs/qemu-ppce500_defconfig | 2 +
> >> configs/qemu-riscv32_defconfig | 1 +
> >> configs/qemu-riscv32_smode_defconfig | 1 +
> >> configs/qemu-riscv32_spl_defconfig | 4 +-
> >> configs/qemu-riscv64_defconfig | 1 +
> >> configs/qemu-riscv64_smode_defconfig | 1 +
> >> configs/qemu-riscv64_spl_defconfig | 3 +-
> >> configs/qemu_arm64_defconfig | 1 +
> >> configs/qemu_arm_defconfig | 1 +
> >> configs/rpi_4_32b_defconfig | 1 +
> >> configs/rpi_4_defconfig | 1 +
> >> configs/rpi_arm64_defconfig | 1 +
> >> configs/vexpress_aemv8a_juno_defconfig | 1 +
> >> configs/xenguest_arm64_defconfig | 2 +-
> >> configs/xilinx_versal_virt_defconfig | 1 +
> >> doc/board/emulation/qemu-arm.rst | 10 +-
> >> doc/board/emulation/qemu-riscv.rst | 3 +
> >> doc/develop/devicetree/dt_qemu.rst | 48 +
> >> doc/develop/devicetree/dt_update.rst | 497 ++++++
> >> doc/develop/devicetree/index.rst | 2 +
> >> dts/Kconfig | 30 +-
> >> include/asm-generic/global_data.h | 8 +
> >> include/fdtdec.h | 21 +-
> >> lib/fdtdec.c | 117 +-
> >> tools/binman/binman.rst | 20 -
> >> 49 files changed, 5538 insertions(+), 124 deletions(-)
> >> create mode 100644 arch/arm/dts/bcm2711-rpi-4-b.dts
> >> create mode 100644 arch/arm/dts/bcm7xxx.dts
> >> create mode 100644 arch/arm/dts/highbank.dts
> >> create mode 100644 arch/arm/dts/juno-r2.dts
> >> create mode 100644 arch/arm/dts/octeontx.dts
> >> create mode 100644 arch/arm/dts/qemu-arm.dts
> >> create mode 100644 arch/arm/dts/qemu-arm64.dts
> >> create mode 100644 arch/arm/dts/xenguest-arm64.dts
> >> create mode 100644 arch/arm/dts/xilinx-versal-virt.dts
> >> create mode 100644 arch/powerpc/dts/qemu-ppce500.dts
> >> delete mode 100644 arch/riscv/dts/qemu-virt.dts
> >> create mode 100644 arch/riscv/dts/qemu-virt32.dts
> >> create mode 100644 arch/riscv/dts/qemu-virt64.dts
> >> create mode 100644 doc/develop/devicetree/dt_qemu.rst
> >> create mode 100644 doc/develop/devicetree/dt_update.rst
> >>
> >> --
> >> 2.34.0.rc2.393.gf8c9666880-goog
> >>
> > --
> > François-Frédéric Ozog | Director Business Development
> > T: +33.67221.6485
> > francois.ozog at linaro.org | Skype: ffozog
> >
>
--
François-Frédéric Ozog | *Director Business Development*
T: +33.67221.6485
francois.ozog at linaro.org | Skype: ffozog
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