On 02/10/2023 20.56, Simon Glass wrote:
Hi Tom,
On Mon, 2 Oct 2023 at 10:22, Tom Rini trini@konsulko.com wrote:
I'm really not sure that replacing build rules with a board CONFIG is a good idea. I suppose part of my confusion is why the Makefile is considered a problem?
Because it's duplicative and as Rasmus points out, often wrong.
To me, that is under the control of the board maintainers. They should not put CONFIG_SYS_BOARD in the DT...it obviously goes against what DT is for and I'm not sure what binding would allow it anyway.
If it helps, I could do a little series to remove those? I think it is just arch/arm/dts/rockchip-optee.dtsi ?
This seems like a case of throwing the baby out with the bathwater.
Huh? I don't think you understood what Tom was referring to, and I certainly don't understand what you're talking about.
(1) duplicative = the _defconfig already has the necessary information in *OF_LIST / DEFAULT_DEVICETREE
(2) often wrong = people add .dts targets to dtb-y, not .dtb targets. They are harmless no-ops because people do get their .dtb files built due to (1). "often" is perhaps a bit of an overstatement.
We are trying to use DT (and not custom C code) to deal with the differences between boards. So long as that is preserved, I am happy enough.
Of course. This has nothing at all to do with C code versus device tree(s). Just how we ensure that all relevant .dtbs that get built today with the massive [mostly redundant] lists will still be built if we remove all those dtb-$(FOO) += lists.
The OF_LIST option is a little vague but I think it means that the DTs are packaged into a FIT in u-boot.img - is that right? But they presumably have to be built first.
No, they don't have to be built first because scripts/Makefile.dts ensures that we build everything in *OF_LIST.
That is from this commit:
3609e1dc5f4 dts: automatically build necessary .dtb files
which was for use by custom boards using a private branch. Did it have a wider purpose that I didn't understand?
Not at the time, but it turns out that since we now _do_ have it, new in-tree boards also don't have to modify an arch/*/dts/Makefile, and do it wrong.
Rasmus