[U-Boot] [RFC PATCH v2 00/12] Add support for applications of overlays in SPL

Jean-Jacques Hiblot jjhiblot at ti.com
Wed Apr 17 12:29:54 UTC 2019

On 17/04/2019 12:38, Michal Simek wrote:
> On 17. 04. 19 11:34, Jean-Jacques Hiblot wrote:
>> Hi Michal,
>> On 28/03/2019 15:03, Michal Simek wrote:
>>> On 27. 03. 19 16:38, Jean-Jacques Hiblot wrote:
>>>> The purpose of this series is to provide the SPL with ability to apply
>>>> overlays for u-boot. this is only a RFC so far, to get a feedback on the
>>>> approach.
>>>> Our use-case is the support of the daughter boards of the AM65x EVM. In
>>>> Linux, each board is supported by a unique overlay. The presence of the
>>>> boards is detected at runtime, and some useful features (like USB) are
>>>> implemented on those daughter boards. Instead of providing multiple dtbs
>>>> and fall in a combinatorial pit, we propose to use DT overlays.
>>>> Patch #1 "spl: fit: Add support for applying DT overlay" has been posted
>>>> a few weeks ago by Michal Simek.
>>>> Patch #2 and #3 amend Michal's patch.
>>>> Patch #4 and #5 are simple fixes for the Makefile
>>>> Patch #6 is not required but relates to this series and will be required
>>>> later by the AM6x platform
>>>> Patch #7 may be a bit controversial. It basically replaces u-boot.img
>>>> with
>>>> a symlink to u-boot.itb in case we use a "complex" FIT (ie: if
>>>> SPL_FIT_SOURCE or SPL_FIT_GENERATOR are set). This breaks buildman for
>>>> several platforms because not all the binaries embedded in the FIT are
>>>> available.
>>>> Patch #9 adds a way to dynamically select the DT overlays. That is
>>>> were we
>>>> would use HW detection to select the required overlays. In that case,
>>>> the
>>>> board-level code tells what overlay it needs (it gives the name of the
>>>> node).
>>>> Patch #10 disables advanced SPL FIT features to keep the size of the
>>>> SPL of
>>>> the am335x_evm in check
>>>> Patch #11 is not required, but demonstrates on a DRA76-evm how this
>>>> series
>>>> can be used.
>>>> On arm, if overlay are supported, this series increases the size of
>>>> the SPL
>>>> by 3-4 kB.
>>>> Changes in v2:
>>>> - reworked board_fit_get_additionnal_images() and how it used in
>>>> spl_fit.c
>>>> - removed dtbo generation from dtso files and use .dts extension for the
>>>>     overlays
>>>> - add dynamic allocation usage in a separate patch
>>>> - defconfig change for the am335x_evm
>>> This series looks better.
>>> Is this able to also handle different images then just dtbs?
>> Sorry I thought  had answered this.
>> Yes this is able to handle different image types, not just dtbos.
>> Have you been able to play with it ? any additional comment ?
> I haven't had a time but series is going in a right direction.
> I found 2 days ago that applying my patch is increasing size for some
> platforms that travis is failing.
> It means I would definitely suggest you to run travis on branch with all
> patches applied to see if this passing or some changes need to happen.

Already done. https://travis-ci.org/jjhiblot/u-boot/builds/511617974

The failures (except dra7 which is unresolved) are all related to the 
generation of u-boot.itb (one patch replaces u-boot.img with a link to 
u-boot.itb, making travis build u-boot.itb)

Was the broken  platform the am335x_evm? In that case, the fix is in the 
series. I disabled advanced FIT features for this platform as this is 
definitely not needed.



> Thanks,
> Michal

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