On Thu, Dec 02, 2021 at 11:36:59PM +0100, François Ozog wrote: > Hi Simon,Tom > > Le jeu. 2 déc. 2021 à 19:34, Tom Rini <tr...@konsulko.com> a écrit : > > > On Thu, Dec 02, 2021 at 11:17:38AM -0700, Simon Glass wrote: > > > Hi Tom, > > > > > > On Thu, 2 Dec 2021 at 11:03, Tom Rini <tr...@konsulko.com> wrote: > > > > > > > > On Thu, Dec 02, 2021 at 10:07:13AM -0700, Simon Glass wrote: > > > > > Hi Tom, > > > > > > > > > > On Thu, 2 Dec 2021 at 09:59, Tom Rini <tr...@konsulko.com> wrote: > > > > > > > > > > > > On Thu, Dec 02, 2021 at 09:49:51AM -0700, Simon Glass wrote: > > > > > > > Hi Tom, > > > > > > > > > > > > > > On Thu, 2 Dec 2021 at 09:38, Tom Rini <tr...@konsulko.com> > > wrote: > > > > > > > > > > > > > > > > On Thu, Dec 02, 2021 at 05:33:53PM +0100, François Ozog wrote: > > > > > > > > > Hi Simon > > > > > > > > > > > > > > > > > > Le jeu. 2 déc. 2021 à 17:00, Simon Glass <s...@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-...@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. > > > > > > > > > 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. > > > > > > > > > > > > > > > > This is the part that I too am still unhappy about. I do not > > want > > > > > > > > reference or fake or whatever device trees in the U-Boot > > source tree. > > > > > > > > We should be able to _remove_ the ones we have, that are not > > required, > > > > > > > > with doc/board/...rst explaining how to get / view one. Not > > adding > > > > > > > > more. > > > > > > > > > > > > > > I understand you don't like it and that others don't as well. I > > wish > > > > > > > it had not come to this. > > > > > > > > > > > > > > However we are only talking about 10 boards, three of which > > don't even > > > > > > > have a devicetree anywhere I can find. > > > > > > > > > > > > > > I think on balance this is a substantial clean-up. I am happy to > > add > > > > > > > whatever caveats and documentation people want to clarify what is > > > > > > > going on here. I'm happy to look at future options where the > > > > > > > devicetree is hosted elsewhere, so long as it is trivial to > > build it > > > > > > > within U-Boot for development purposes. > > > > > > > > > > > > > > I'll also note that the bootstd series shows the devicetree > > source: > > > > > > > > > > > > > > Core: 246 devices, 88 uclasses, devicetree: board > > > > > > > > > > > > > > But for now, I still feel this is the best path forward. > > > > > > > > > > > > I'm not sure how to proceed here. The reviews are rather strongly > > > > > > against the "include a device tree that won't be used". The use > > case of > > > > > > "but for development someone might need to modify the device tree" > > is > > > > > > handled by platforms documenting where / how to get the real one. > > We > > > > > > should even update the Kconfig help to note that if you enable > > this your > > > > > > board docs MUST explain where the device tree can be seen (or have > > some > > > > > > legal reason you think it's OK to not...). > > > > > > > > > > Right, we can do lots of things as we have discussed. I am very > > > > > willing to work on these and make sure it is hard to do the thing. > > But > > > > > this series is long enough already. > > > > > > > > Yes, I think the rest of us had hoped you would come around to all of > > > > our reasoning by this point, is why this is taking so long. > > > > > > > > > > Look, if I thought this was all wrong I would not be doing it. We have > > > a range of opinions: > > > > And the rest of us wouldn't keep trying to argue otherwise if we didn't > > see problems with it, still. > > > > > - U-Boot should not have its own nodes/properties > > > > The caveat there is that aren't documented upstream bindings. I think > > at this point the lack of screaming and otherwise "wait, no no no > > don't!" that your current patch has gotten means it's time for a pull > > request, and for that to go in, and so this line of argument would be > > simply removed. > > > > > - U-Boot should not have DTs in-tree > > > > ... for the cases where the DTs are not used at run time, yes. > > > > > - U-Boot should have DTs only when essential > > > > I don't understand this point. Can you please elaborate? > > > > > - U-Boot should have DTs in-tree for all boards > > > > This is the line you're pushing and almost every other reviewer > > disagrees with. > > For the sake of getting interesting parts of the patch set in and “move > on”, what about: > providing an empty (see below) DT for boards for which U-Boot receives the > “source of truth” so that there are no build issues. > The empty DT contains a comment that explains the DT lifecycle for the > board and points to the documentation tree for sample DTs. > The boards would the ones we talked about and SystemReady boards > https://www.arm.com/why-arm/architecture/systems/systemready-certification-program/ir?_ga=2.35159527.79382615.1638484482-159131740.1638484482
My ROCKPro64 is on the way still, but I'm not sure what SystemReady IR has to do with this exactly. I mean this very much seriously as I was doing some testing with another platform in preparation for certification and I was just using the device tree that in U-Boot. Perhaps I just missed a section in one of the documents however. -- Tom
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