arch: arm: core: aarch32: support for On-Chip Memory (OCM) areas in aarch32

Introduce support for On-Chip Memory (OCM) areas in aarch32 Cortex-A
SoCs. This memory area is suitable for, amongst other things, un-
cached device DMA. The OCM memory can reside either at address zero
or at a high memory address, with configuration of the memory's lo-
cation similar to the configuration of the location of the exception
vectors. In both cases, it must be assured that the low/high OCM
area declaration doesn't overlap with the exception vectors memory
page at either the low/high address. Therefore, all possible OCM
location options shall be described in the SoC's device tree, the
current location shall be indicated via a "chosen" entry in the
target board's device tree.

This commit contains the necessary changes to the linker-related
files as well as the static region declaration for the MMU in-
itialization in the Zynq-7000 SoC-specific init code.

Signed-off-by: Immo Birnbaum <Immo.Birnbaum@weidmueller.com>
4 files changed