[PATCH RFC] rockchip: add /chosen/bootsource to U-Boot proper DT

[Quentin Schulz]

Hi Tom,

On 8/12/25 4:15 PM, Tom Rini wrote:
> On Tue, Aug 12, 2025 at 03:15:00PM +0200, Quentin Schulz wrote:
>> Hi Tom,
>>
>> On 7/30/25 7:24 PM, Tom Rini wrote:
>>> On Wed, Jul 30, 2025 at 02:03:18PM +0200, Quentin Schulz wrote:
>>>
>>>> From: Quentin Schulz <quentin.schulz at cherry.de>
>>>>
>>>> U-Boot typically can be loaded from different storage media, such as
>>>> eMMC, SD card, SPI flash, but also from non-persistent media such as USB
>>>> (via proprietary protocols loading directly into SRAM, or fastboot, DFU,
>>>>    etc..), JTAG, ...
>>>>
>>>> This information is usually reported by the BootROM via some proprietary
>>>> mechanism (some specific address in registers/DRAM for example). For
>>>> Rockchip, that information is stored in a register
>>>> (BROM_BOOTSOURCE_ID_ADDR).
>>>>
>>>> While we already have the information about which medium was used to
>>>> load U-Boot proper from SPL (via /chosen/u-boot,spl-boot-device), this
>>>> new property represents the medium used to load U-Boot first phase
>>>> (depending on configuration, can be VPL/TPL/SPL) which absolutely may
>>>> differ from the one used to load U-Boot proper!
>>>>
>>>> It would be useful to know which medium was used to load the first phase
>>>> of U-Boot, for example to check fallback mechanisms (proper loaded from
>>>> a different medium than first phase) are actually working.
>>>>
>>>> For now, this only applies to Rockchip's U-Boot proper DT but could be
>>>> applied to the kernel's as well and possibly for other architectures or
>>>> vendors.
>>>>
>>>> Signed-off-by: Quentin Schulz <quentin.schulz at cherry.de>
>>>> ---
>>>> I have a board (RK3399 Puma) running U-Boot which currently has 9 boot
>>>> scenarios (eMMC/SD/SPI-NOR for the first phase, eMMC/SD/SPI-NOR for the
>>>> next phases; not counting USB loading yet, which would make it a few
>>>> more). I cannot force the BootROM of this board to select a specific
>>>> device aside from erasing the other media.
>>>>
>>>> The only way to identify which device was used for the first phase is to
>>>> parse U-Boot first phase console output or add some custom logic for my
>>>> board. To validate that a new version of the bootloader works, including
>>>> the fallback mechanisms, I need to make sure the BootROM loads the first
>>>> phase from the expected device otherwise I may have false positives.
>>>> This would be useful for automated testing.
>>>>
>>>> Patches pending in the devicetree-spec[1] and dt-schema[2], hence the
>>>> RFC here.
>>>>
>>>> [1] https://lore.kernel.org/devicetree-spec/20250505-bootsource-v2-1-5a315d9bff26@cherry.de/
>>>> [2] https://github.com/devicetree-org/dt-schema/pull/169
>>>
>>> I am conceptually fine with the changes, but this needs to have the
>>> schema side approved first, just for the record.
>>>
>>
>> Now merged in the dt-schema (still no news on the spec side though aside
>> from a R-b from Simon 2 months ago). Is that good enough or do we need to
>> wait on the spec part too?
> 
> Ah good, OK. So should this be in v2025.10 or will v2026.01 be OK? It's
> small enough I'm OK taking it now.
> 

I'm fine with v2026.01, there's no hurry for me as I can carry it in my 
downstream forks until it's merged upstream.

So, up to you!

Cheers,
Quentin