i.MX 7's Cortex-M4 core can run from DDR and uses DDR memory for the rpmsg communication. Both use cases need a fixed location of memory reserved. For the rpmsg use case the reserved area needs to be in sync with the kernel's hardcoded vring descriptor location.
Introduce support for adding linux,usable-memory property to carve out 1MB of memory in case the M4 core is running. Also make sure that the i.MX 7 specific rpmsg driver does not get loaded in case we do not carve out memory.
v2: - fixed build where CONFIG_ARCH_FIXUP_FDT_MEMORY is not set.
Igor Opaniuk (2): common: fdt_support: add support for setting usable memory board: colibri_imx7: reserve DDR memory for Cortex-M4
arch/arm/include/asm/mach-imx/sys_proto.h | 2 ++ board/toradex/colibri_imx7/colibri_imx7.c | 37 +++++++++++++++++++++++ common/fdt_support.c | 35 +++++++++++++++++++++ include/fdt_support.h | 1 + 4 files changed, 75 insertions(+)