Re: [PATCH v2 7/8] arm: u8500: Switch Stemmy to upstream Janice device tree

On Mon, Aug 17, 2026 at 6:45 PM Stephan Gerhold
<[email protected]> wrote:

> Hm okay so you're basically dropping support for the internal eMMC in
> this patch? Can we support both? BOOTSTD should be able to scan multiple
> storages for boot targets.

Yeah just laziness on my part, I'll fix it up.

> I'm also not really sure about selecting Janice as "default" device tree
> here. Do you expect users to change this setting when they want to build
> stemmy for another board?

I have a script that loops over the Samsung device trees,
and recompiles U-Boot for each of them.
https://dflund.se/~triad/krad/makefiles/ux500-uboot.mak

> I wonder if we could continue using a single generic binary for all
> boards using CONFIG_MULTI_DTB_FIT. We should have "fw_mach" in
> board/ste/stemmy/stemmy.c that should tell us which device we are
> running on, which seems to be mostly(?) unique:
>
> https://github.com/stericsson-mainline/android_kernel/blob/9508895090960012f916561b2ede5eaf8124fabd/arch/arm/tools/mach-types#L3956-L3965
>
> I'm not sure about codina-tmo, you would need to check which number the
> bootloader passes.
>
> If these numbers are unique, it should be easy to implement
> board_fit_config_name_match().

I see the appeal of the ambition to have a "one size fits (pun!) all"
U-Boot.

But as it is, some of the DTS attributes on the external SD card are
different between the platforms, so we would need to modify the
U-Boot internal Stemmy device tree for those, copying over yet
properties from the device trees and into the boardfile.

For example Janice and Codina uses a regulator for
vqmmc-supply, and those using the "sd_level_translator"
for vqmmc-supply actually use different GPIO pins on say
Gavini compared to Codina or Golden.

The pin direction settings on the MMC host vary. (Some of
these were really tricky to get right.)

So I think no, if we want external SD card boot we need
per-device compiled U-Boot binaries with the unique device
trees.

Yours,
Linus Walleij