[U-Boot] [RFC PATCH v1 0/9] Add support for applications of overlays in SPL

[Jean-Jacques Hiblot]

On 27/03/2019 10:39, Lukasz Majewski wrote:
> Hi Jean-Jacques,
>
>> 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.
>>
>> The first 4 patches are small fixes/improvement related to the build.
>> Patch #5 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)
>>
>> Patch #6 and #7 are the core support for DTB application in the SPL.
>> Based on a patch posted by Michal Simek a few weeks ago. The list of
>> overlays is read from the "fdt" of the configuration chosen in the
>> ITB (same property as for the DTB):
>>    configurations {
>>       default = "conf-1";
>>       conf-1 {
>>         description = "dra76-evm";
>>         firmware = "firmware-1";
>>         fdt = "fdt-1", "overlay-1";
>>        };
>>    }
>>
>>
>> Patch #8 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 #9 is not required, but demonstrates on a DRA76-evm how this
>> series can be used.
>>
>>
>> Jean-Jacques Hiblot (8):
>>    dtbo: also generate dtbo from dtso
>>    Makefile.lib: include /__symbols__ in dtb if OF_LIBFDT_OVERLAY is
>>      enabled
>>    Makefile: Fix u-boot.itb generation when building outside the source
>>      tree
>>    Makefile: Pass the board name to the FIT generator scripts
>>    Makefile: use custom ITS to build u-boot.img if SPL_FIT_SOURCE or
>>      SPL_FIT_GENERATOR are set
>>    spl: fit: Allow calling spl_load_fit_image() to only get the image
>>      size
>>    sp: fit: Allow the board to dynamically select the DTB overlays it
>>      needs.
>>    !!! TEMP !!! For demonstration only !!! DRA76: Usage of overlays in
>>      SPL
>>
>> Michal Simek (1):
>>    spl: fit: Add support for applying DT overlay
> Just out of curiosity - what is the difference in SPL footprint when
> with and without this feature?

For the dra76-evm, the diff in SPL size is 3.3kB

JJ


>
>>   Makefile                                      |  20 ++-
>>   arch/arm/dts/Makefile                         |   2 +-
>>   arch/arm/dts/dra76-evm-dummy.dtso             |  14 +++
>>   arch/arm/dts/dra76-evm-dummy2.dtso            |  15 +++
>>   arch/arm/mach-imx/mkimage_fit_atf.sh          |   3 +-
>>   arch/arm/mach-rockchip/make_fit_atf.py        |   5 +-
>>   .../lion_rk3368/fit_spl_atf.its               |   6 +-
>>   .../puma_rk3399/fit_spl_atf.its               |   8 +-
>>   board/ti/dra7xx/evm.c                         |  30 +++++
>>   board/ti/dra7xx/evm.its                       |  48 ++++++++
>>   common/spl/spl_fit.c                          | 114
>> +++++++++++++++++- configs/dra7xx_evm_defconfig                  |
>> 2 + include/spl.h                                 |  20 +++
>>   scripts/Makefile.lib                          |   7 ++
>>   14 files changed, 273 insertions(+), 21 deletions(-)
>>   create mode 100644 arch/arm/dts/dra76-evm-dummy.dtso
>>   create mode 100644 arch/arm/dts/dra76-evm-dummy2.dtso
>>   create mode 100644 board/ti/dra7xx/evm.its
>>
>
>
>
> Best regards,
>
> Lukasz Majewski
>
> --
>
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