Boot loader: u-boot: Issues and future developments

[m-weigand]

This is a meta issue, meant as a starting point for people looking to help.

Current state

• We use this upstream-based u-boot repo: https://github.com/m-weigand/u-boot-pinenote

• this includes a rough port of the cyttsp5 driver to u-boot for touch input (https://github.com/m-weigand/u-boot-pinenote/blob/branch_cyttsp5ub/drivers/input/cyttsp5ub.c)

• this branch also includes the upstream ebc driver

• We do not have UMS enalbed

• This branch does not support compressed kernel images

Future

• It would probably be nice to switch to mainline, or something very much related to it: https://wiki.pine64.org/wiki/ Quartz64_Building_U-Boot (this can be accomplished using the rockchip-provided rkbin blobs, but would require porting the touch/ebc-specific stuff)
• There is work ongoing related to using opened TF-A parts in u-boot, see, for example, here:
  https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/31265/comments/b3a9d59e_61a913d7?tab=comments