On Tue, May 21, 2019 at 10:14 PM Simon Glass sjg@chromium.org wrote:
Hi,
(moved from thread "U-Boot PXA support")
We have of-platdata, which produces C data from the DT, for linking into U-Boot. It saves libfdt and DT space. But we still have the DM overhead.
We have binman which can insert values into the binary after link-time. This is barely used at present, only for accessing the location of things in flash.
Another thing is that every little tweak and feature adds a few bytes and there are dozens of them in each release. It would be interesting to build a board from 10 years ago (like PXA) and see where the growth is. My bet is that we could add Kconfig options to disable extra features (and enhancements of features) and make quite a difference.
For DM, I think it would be interesting to revisit and compare against the initial release, and see if some features could be made optional in SPL.
Finally I feel we could implement a single-device API for where CONFIG_SPL_DM is not set. We could use the debug UART for serial, a single instance of tiny MMC for MMC, etc.
This is what I'm looking for quite sometime, a tiny MMC which would bypass the mmc stack and do the possible stuff in SPL, since we don't have any option to use full DM in SPL (specifically for Allwinner 64 SoC's). API that would atleast compatible with DM with small foot-print would help.