Hi Bjørn,
On Sun, 6 Nov 2022 at 11:20, Bjørn Mork bjorn@mork.no wrote:
Properties are sometimes used to store data with stricter alignment requirements than the 4-byte fdt tag alignment. Aligning the offset of the property data will alloe a client to directly address it, without reloaction, provided the fdt is loaded on a similarily aligned boundary.
One known use-case for this is the U-Boot FIT images, which may embed nested fdt blobs inside properties of the outer FIT fdt. Although strongly discouraged, U-Boot can be configured to use these embedded blobs "in place". This is discouraged because if only will work if the offset of the property value, i.e. the embedded fdt, happens to match the 8-byte boundary required by the devicetree spec.
Adding the ability to align property data allows U-Boot tools to reliably create FIT images for such use.
Other use cases are currently not known, but anticipated.
Signed-off-by: Bjørn Mork bjorn@mork.no
scripts/dtc/libfdt/fdt_rw.c | 26 ++++++++++++++++++++++++ scripts/dtc/libfdt/fdt_wip.c | 2 +- scripts/dtc/libfdt/libfdt.h | 30 ++++++++++++++++++++++++++++ scripts/dtc/libfdt/libfdt_internal.h | 1 + 4 files changed, 58 insertions(+), 1 deletion(-)
Can you use an external FIT?
Regards, Simon