arm64: dts: renesas: ironhide: Describe all reserved memory

Fully describe all available DRAM in the DT, and describe regions which
are not accessible because they are used by firmware in reserved-memory
nodes.

Replace the first memory bank memory@60600000 with memory@40000000 and a
518 MiB long reserved-memory no-map subnode. This memory region is used
by other cores in the system.

Reserve 32 kiB of memory at 0x8c100000 for parameters shared by IPL,
SCP, TFA BL31 and TEE.

Reserve 512 kiB of memory at 0x8c200000 for TFA BL31.  The upcoming
upstream TFA 2.15 BL31 uses memory from 0x8c200000..0x8c242fff; rounding
up to 512 kiB is slight future-proofing.

Reserve 32 MiB of memory at 0x8c400000 for OPTEE-OS, which is the entire
OPTEE-OS TZ protected DRAM area.

Neither TFA BL31 nor OPTEE-OS modify the DT passed to Linux in any way
with any new reserved-memory {} nodes to reserve memory areas used by
the TFA BL31 or OPTEE-OS to prevent the next stage from using those
areas, which lets Linux use all of the available DRAM as it is described
in the DT that was passed in by U-Boot, including the areas that are
newly utilized by TFA BL31 or OPTEE-OS.

In case of high DRAM utilization, unless the memory used by TFA BL31 or
OPTEE-OS is properly reserved, Linux may use and corrupt the memory used
by TFA BL31 or OPTEE-OS, which would lead to the system becoming
unresponsive.

Fixes: ad142a4ef710 ("arm64: dts: renesas: r8a78000: Add initial Ironhide board support")
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20260517163212.18016-1-marek.vasut+renesas@mailbox.org
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

0 files changed, 0 insertions, 0 deletions