[U-Boot] [RFC PATCH 00/11] extend FIT loading support (plus Pine64/ATF support)

[Andre Przywara]

Currently the FIT format is not used to its full potential in the SPL:
It only loads the first image from the /images node and appends the
proper FDT.
Some boards and platforms would benefit from loading more images before
starting U-Boot proper, notably Allwinner A64 and ARMv8 Rockchip boards,
which use an ARM Trusted Firmware (ATF) image to be executed before U-Boot.

This series tries to solve this in a board agnostic and generic way:
We extend the SPL FIT loading scheme to allow loading multiple images.
So apart from loading the image which is referenced by the "firmware"
property in the respective configuration node and placing the DTB right
behind it, we iterate over all strings in the "loadable" property.
Each image referenced there will be loaded to its specified load address.
The entry point U-Boot eventually branches to will be taken from the
first image to explicitly provide the "entry" property, or, if none
of them does so, from the load address of the "firmware" image.
This keeps the scheme compatible with the FIT images our Makefile creates
automatically at the moment.

Apart from the already mentioned ATF scenario this opens up more usage
scenarios, of which the commit message of patch 04/11 lists some.

The first three patches rework the SPL FIT support to be more flexible
and to allow easier usage in the fourth patch, which introduces the
multiple-image loading facility.
The remaining patches enable that support for the Pine64 board to make
its SPL support finally useful and to demonstrate usage of this scheme:
patches 5-7 extend the usable SPL size by about 4 KB to allow AArch64
compilation of the SPL with FIT support enabled. Patch 8 implements the
board selector routine, which selects either the Pine64 or Pine64+ DTB
depending on the detected DRAM size. Patch 9 enables SPL FIT support in
the Pine64 defconfig.
To demonstrate the usage, patch 10 provides a FIT source file, which
loads and executes ATF before the U-Boot proper. Users are expected to
compile this with "mkimage -f boards/sunxi/pine64_atf.its -E pine64.itb",
then write the resulting file behind the SPL on an SD card (or any other
U-Boot supported boot media, for that matter).
Patch 11 then adds FIT support to the sunxi SPL SPI loading routine,
which allows to load ATF on boards with SPI flash as well.

Questions:
1) Is this scheme the right one (usage of "firmware" and "loadables",
   determination of entry point)? Shall we make use of the "setup"
   property?
2) Shall we extend mkimage to allow supplying "loadable" files on the
   command line, which would allow to build the .itb file automatically?
3) Is providing the .its source file for a (family of) boards the right
   way?
4) Does this break any boards which already use SPL FIT loading?

And for the Pine64 part:
5) Is extending the usable SPL size like in patch 5-7 acceptable?

I have a more generic solution for the .dtb selection in mind: Based on
some patch from Siarhei we store the .dtb filename in the SPL header and
select the .dtb from the FIT image by simply matching the name. This would
allow _one_ build supporting multiple boards. The actual board name would
need to written into the SPL header or could be copied from there when
updating the image.
I can provide the patches once we agreed upon this series.

Please let me know what you think!

Cheers,
Andre.

Andre Przywara (11):
  SPL: FIT: refactor FDT loading
  SPL: FIT: rework U-Boot image loading
  SPL: FIT: factor out spl_load_fit_image()
  SPL: FIT: allow loading multiple images
  tools: mksunxiboot: allow larger SPL binaries
  sunxi: A64: SPL: allow large SPL binary
  sunxi: A64: move SPL stack to end of SRAM A2
  sunxi: SPL: add FIT config selector for Pine64 boards
  sunxi: Pine64: defconfig: enable SPL FIT support
  sunxi: Pine64: add FIT image source
  SPL: SPI: sunxi: add SPL FIT image support

 board/sunxi/board.c             |  13 +++
 board/sunxi/pine64_atf.its      |  54 +++++++++
 common/spl/spl_fit.c            | 241 +++++++++++++++++++++++-----------------
 configs/pine64_plus_defconfig   |   5 +
 drivers/mtd/spi/sunxi_spi_spl.c |  39 +++++--
 include/configs/sunxi-common.h  |   6 +-
 scripts/Makefile.spl            |   7 +-
 tools/mksunxiboot.c             |  51 ++++++---
 8 files changed, 290 insertions(+), 126 deletions(-)
 create mode 100644 board/sunxi/pine64_atf.its

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2.8.2