fix(rpi4): drop /memreserve/ region

Most DTBs used on the RaspberryPi contain a FDT /memreserve/ region,
that covers the original secondaries' spin table.
We need to reserve more memory than described there, to cover the whole
of the TF-A image, so we add a /reserved-memory node to the DTB.

However having the same memory region described by both methods upsets
the Linux kernel and U-Boot, so we have to make sure there is only one
instance describing this reserved memory.

Keep our currently used /reserved-memory node, since it's more capable
(it allows to mark the region as secure memory). Add some code to drop
the original /memreserve/ region, since we don't need this anymore,
because we take the secondaries out of their original spin loop.

We explicitly check for the currently used size of 4KB for this region,
to be alerted by any changes to this region in the upstream DTB.

Change-Id: Ia3105560deb3f939e026f6ed715a9bbe68b56230
Signed-off-by: Andre Przywara <>
1 file changed