fix(rcar3-drivers): disable A/B loader support by default
The A/B loader [1] meant to be used for convenient CI testing.
The tool is installed into the same location as SA0, where it
conveniently fits due to its size, and where it makes use of
non-volatile PMIC registers to alternate between loading and
starting A or B copy of the BL2. The PMIC registers are used
because CPU registers are lost across reset.
In case the B copy is loaded, it is loaded from 8 MiB offset
from start of HF. In case the B copy fails to boot, a simple
reset of the system will switch back to booting previously
known working A copy and allow recovery.
The A/B loader sets MFIS bit MFISBTSTSR_BOOT_PARTITION to
pass the information which A/B copy is currently booting on
to TFA, which then loads the follow up components from 0 MiB
or 8 MiB offset, depending on whether the A or B copy is being
booted.
The MFISBTSTSR_BOOT_PARTITION interferes with regular A/B
switching during boot from eMMC as the boot media, where
the BootROM also sets MFISBTSTSR_BOOT_PARTITION bit in case
the system boots from SECOND eMMC HW BOOT partition.
Since the A/B loader is meant as a development and CI tool,
isolate the A/B loader use to RPC HF only and furthermore
isolate it behind new RCAR_RPC_HYPERFLASH_ABLOADER option
which is disabled by default.
[1] https://github.com/marex/abloader
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Change-Id: I04ecd50fa1405b78e1ba3949d54029034d4f22d8
2 files changed