Hi Simon,
In order to make people easier to maintain a U-Boot for product,
we want to re-use the dtb from kernel. Some peripheral like power/pmic
and display panel, key, charger which need work in U-Boot and may different
in different product, we want to make people only maintain kernel dts, but not
one more U-Boot project for all these devices.
I want to do this just around the
relocate, need to read dtb from storage like emmc/nand/spi, and then use
a new dtb for initr_dm after relocate.
Here are issues I have met:
- The kernel dts may not have a stdout in chosen, we may use earlycon, earlyprintk instead;
this lead to U-Boot can not find a serial driver after relocate;
- no alias for mmc device which is need by U-Boot but not used in kernel;
- not able to init mmc driver twice with current driver;
mmc driver not able to work before relocate, no bss for (static int initialized), and hang even
if I skip this;
mmc driver can init and read dtb before initr_dm, but not able to init again after initr_dm.
In fact, I don't think we have to re-init serial driver and mmc driver, and most other driver which
need pre-relocate like clock, the only driver I have seem have different use in pre-relocate and post-relocate
is video driver(no idea why it have to be pre-relocate, we always have display very late),
can we add a tag for re-use the dm driver data for those with pre-relocate ?
Thanks,
- Kever