[U-Boot] [PATCH PATCH v3 00/12] Add support for applications of overlays in SPL

Jean-Jacques Hiblot jjhiblot at ti.com
Tue Jun 25 19:10:24 UTC 2019

Hi Simon,

On 22/06/2019 21:09, Simon Glass wrote:
> Hi Jean-Jacques,
> On Thu, 23 May 2019 at 11:39, Jean-Jacques Hiblot <jjhiblot at ti.com> 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 to #5 amend Michal's patch.
>> Patch #6 to #8 are simple fixes for the Makefile
>> Patch #9 is not required but relates to this series and will be required
>> later by the AM6x platform
>> Patch #10 is used to reduce the complexity of the Makefile by having FIT
>> generator scripts provide their dependencies
>> Patch #12 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).
>> On arm, if overlay are supported, this series increases the size of the SPL
>> by 3.2 kB.
>> Travis build : https://travis-ci.org/jjhiblot/u-boot/builds/535686392
>> For a strange reason, buildman on travis show errors for sun8i ans sun50i,
>> but pass when I run it locally.
>> Changes in v3:
>> - Add a new config option: SPL_LOAD_FIT_APPLY_OVERLAY. By default, it is
>> not selected.
>> - removed the RFC prefix. This work will be needed soon by TI's AM65x
>> platform. and can probably benefit other modular platforms
>> - removed the last patch that provided an example of how to use this with
>> on a DRA76.
>> - removed the patch that made u-boot.img a symlink to u-boot.itb because
>> it breaks the build of many platforms (because files required to build the
>> ITB are missing)
>> - removed the patch to reduce the footprint of the am335x SPL. (already
>> merged)
>> - Made the boot flow more permissive (don't fail immediately if an overlay
>> is not present) and more verbose when an error occures
>> - handle the dependencies of the FIT generation in a more generic way
>> - use a dedicated kconfig option to enable the application of the overlays
>> by the SPL.
>> 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
>> Jean-Jacques Hiblot (11):
>>    spl: fit: Make room in the FDT before applying overlays
>>    spl: fit: allocate a temporary buffer to load the overlays
>>    spl: fit: Do not fail immediately if an overlay is not available
>>    spl: fit: be more verbose when an error occurs when applying the
>>      overlays
>>    Makefile.lib: include /__symbols__ in dtb if
>>      SPL_LOAD_FIT_APPLY_OVERLAY is enabled
>>    Makefile: Fix tests for CONFIG_SPL_LOAD_FIT and
>>    Makefile: Fix u-boot.itb generation when building outside the source
>>      tree
>>    Makefile: Pass the board name to the FIT generator scripts
>>    Makefile: Query the SPL Fit Generator for its dependencies
>>    spl: fit: constify the output parameter of spl_fit_get_image_name()
>>    spl: fit: Allow the board to tell if more images must be loaded from
>>      FIT
>> Michal Simek (1):
>>    spl: fit: Add support for applying DT overlay
>>   Kconfig                                       | 10 +++
>>   Makefile                                      | 23 +++--
>>   arch/arm/mach-imx/mkimage_fit_atf.sh          | 10 ++-
>>   arch/arm/mach-rockchip/make_fit_atf.py        | 13 ++-
>>   board/sunxi/mksunxi_fit_atf.sh                |  7 ++
>>   .../lion_rk3368/fit_spl_atf.its               |  6 +-
>>   .../puma_rk3399/fit_spl_atf.its               |  8 +-
>>   common/spl/spl_fit.c                          | 90 +++++++++++++++++--
>>   include/spl.h                                 | 16 ++++
>>   scripts/Makefile.lib                          |  4 +
>>   10 files changed, 156 insertions(+), 31 deletions(-)
> How about a test that uses sandbox to apply some overlays?

I had had a look  it but came to the conclusion that the SPL is not 
passing the FDT to u-boot. Were I mistaken ?

Thanks for the reviews, I'll take your comments in account for the next 


> Regards,
> Simon

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