[U-Boot] [PATCH v5 00/15] Add support for applications of overlays in SPL

Jean-Jacques Hiblot jjhiblot at ti.com
Fri Sep 20 15:28:08 UTC 2019

The purpose of this series is to provide the SPL with ability to apply
overlays for u-boot.

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 #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 v5:
- Do not allocate the buffer if not needed (no overlay).
- Add a Kconfig option for the buffer size
- board_get_fit_loadable() returns an error code instead of a NULL string
  in case of failure
- reword some commit logs

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
- 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:
- depend on SPL_DM
- update the commit log
- 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
- 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
  Makefile.lib: include /__symbols__ in dtb if
  Makefile: Fix tests for CONFIG_SPL_LOAD_FIT and
  Makefile: Fix u-boot.itb generation when building outside the source
  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
  spl: fit: Allow the board to tell if more images must be loaded from

Michal Simek (1):
  spl: fit: Add support for applying DT overlay

 Kconfig                                       |  18 +++
 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                          | 113 ++++++++++++++++--
 drivers/Makefile                              |   2 +-
 drivers/board/Kconfig                         |   3 +
 drivers/board/Makefile                        |   2 +-
 drivers/board/board-uclass.c                  |  11 ++
 include/board.h                               |  74 ++++++++++++
 scripts/Makefile.lib                          |   4 +
 14 files changed, 251 insertions(+), 27 deletions(-)


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