mainboard/qemu-riscv: Get top of memory from device-tree blob

Trying to probe RAM space to figure out top of memory causes an
exception on RISC-V virtual machines with recent versions of QEMU, but
we temporarily enable exception handlers for that and use it to help
detect if a RAM address is usable or not. However, QEMU docs recommend
reading device information from the device-tree blob it provides us at
the start of RAM.

A previous commit adds a library function to parse device-tree blob that
QEMU provides us. Use it to determine top of memory in RISC-V QEMU
virtual machines, but still fall back to the RAM probing approach as a
last-ditch effort.

Change-Id: I9e4a95f49ad373675939329eef40d7423a4132ab
Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/80363
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Maximilian Brune <maximilian.brune@9elements.com>

0 files changed, 0 insertions, 0 deletions