Device-trees are often Linux version specific. So it seems reasonable to let GRUB load device-trees according to the selected kernel version. What currently is missing is a means to let the firmware apply necessary fix-ups.
In the Device Tree Evolution Project (DTE) the idea was born to provide a UEFI protocol which can be called by a boot manager to request the firmware to apply fix-ups to a device-tree. A draft specification for such a protocol can be found at: https://github.com/U-Boot-EFI/EFI_DT_FIXUP_PROTOCOL The first patch implements the protocol. The second allows the dtbdump.efi test tool to load a flattened device-tree and call the EFI_DT_FIXUP_PROTOCOL to apply fix-ups, make memory reservations and finally install the device tree as a configuration table. In a next step this configuration table can be dumped to a file. Heinrich Schuchardt (2): efi_loader: implement EFI_DT_FIXUP_PROTOCOL efi_selftest: dtbdump support EFI_DT_FIXUP_PROTOCOL cmd/bootefi.c | 80 --------- cmd/efidebug.c | 5 + include/efi_dt_fixup.h | 39 +++++ include/efi_loader.h | 2 + lib/efi_loader/Makefile | 3 + lib/efi_loader/efi_dt_fixup.c | 160 ++++++++++++++++++ lib/efi_loader/efi_root_node.c | 6 + lib/efi_selftest/dtbdump.c | 298 +++++++++++++++++++++++++++++---- 8 files changed, 477 insertions(+), 116 deletions(-) create mode 100644 include/efi_dt_fixup.h create mode 100644 lib/efi_loader/efi_dt_fixup.c -- 2.29.2
