[U-Boot] [PATCH PATCH v4 00/15] Add support for applications of overlays in SPL

[Simon Glass]

Hi Jean-Jacques,

On Mon, 5 Aug 2019 at 03:44, 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.

But why do this in SPL? Is it so U-Boot can use the DT with overlays
itself for driver model?

>
> Patch #2 "spl: fit: Add support for applying DT overlay" has been posted
> a few weeks ago by Michal Simek.
> Patch #3 to #6 amend Michal's patch.
> Patch #7 to #9 are simple fixes for the Makefile
> Patch #10 is used to reduce the complexity of the Makefile by having FIT
> generator scripts provide their dependencies
> Patch #12-#13 allow to use the board driver in SPL
> Patch #14-#15 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 driver 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/567779404
>
> Changes in v4:
> - use CONFIG_IS_ENABLED() instead of #idef
> - make sure that the temp buffer is freed in all cases
> - Use the board driver infrastructure to get the image names from the
> board code.
> - Remove a patch that passed the board name to the FIT generator. If needed
> the generator can get it from elsewhere
> - Add a fix to not load the firmware twice (once as a firmware and once as
> a loadable)
>
> 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 (14):
>   spl: fit: don't load the firmware twice
>   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
>     CONFIG_SPL_FIT_GENERATOR
>   Makefile: Fix u-boot.itb generation when building outside the source
>     tree
>   Makefile: Query the SPL Fit Generator for its dependencies
>   spl: fit: constify the output parameter of spl_fit_get_image_name()
>   drivers: board: Make the board drivers available in SPL
>   drivers: board: Add get_fit_loadable()
>   include: board: provide empty stubs when the BOARD option is not
>     selected
>   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                                       |   9 ++
>  Makefile                                      |  23 ++--
>  arch/arm/mach-imx/mkimage_fit_atf.sh          |   5 +
>  arch/arm/mach-rockchip/make_fit_atf.py        |   7 ++
>  board/sunxi/mksunxi_fit_atf.sh                |   4 +
>  .../lion_rk3368/fit_spl_atf.its               |   6 +-
>  .../puma_rk3399/fit_spl_atf.sh                |   6 +
>  common/spl/spl_fit.c                          | 104 ++++++++++++++++--
>  drivers/Makefile                              |   2 +-
>  drivers/board/Kconfig                         |   2 +
>  drivers/board/Makefile                        |   2 +-
>  drivers/board/board-uclass.c                  |  11 ++
>  include/board.h                               |  72 ++++++++++++
>  scripts/Makefile.lib                          |   4 +
>  14 files changed, 230 insertions(+), 27 deletions(-)
>
> --
> 2.17.1
>

Please can we have a sandbox test for this?

Regards,
SImon