[PATCH] ARM: dts: sunxi: Add MMC alias for consistent enumeration
Stefan Gloor
code at stefan-gloor.ch
Sun Jan 5 04:47:55 PST 2025
Hi Chen-Yu and Andre, thank you for your input.
On 01.01.25 09:58, Chen-Yu Tsai wrote:
> IIRC we have chosen against adding explicit MMC aliases for the sunxi
> platforms. Please try using UUID= or PARTUUID= for root partition
> references.
I see, no problem. Out of curiosity, what is the reason for this
decision? I couldn't find related discussions on the mailing list.
Personally, I like the UUID= or PARTUUID= method and I do have a working
Yocto setup that uses PARTUUID to find the rootfs. It integrates nicely
with the automatic disk/uuid creation and U-boot using extlinux.conf
[1]. I do however understand that this requires major changes to the
meta-sunxi layer and the maintainers don't like breaking a working
system with U-boot scripts. So I went with the easier way of adding
aliases. For future reference to anyone, this patch has now been added
downstream to meta-sunxi [2].
[1] https://github.com/linux-sunxi/meta-sunxi/pull/431
[2] https://github.com/linux-sunxi/meta-sunxi/pull/432
On 02.01.25 00:28, Andre Przywara wrote:
> Yes, and LABEL= would be another way.
>
> Alternatively you could use U-Boot's DT when booting the board. U-Boot
> will add those aliases during build time (because it needs them for its
> own purposes), and by using $fdtcontroladdr (instead of $fdt_addr_r,
> on the bootz command line) you get this for free, and even save yourself
> from loading some DT.
> We sync the DTs regularly from the kernel to U-Boot now, and at the
> moment they are identical between the kernel and U-Boot, so you don't
> lose anything.
Thanks Andre for the helpful tips. I'll remember this for future reference.
Best,
Stefan
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