VBE provides the ability for an OS to request that information be passed to it when it is booted. This is added into the /chosen node, in addition to things like the bootargs for Linux, for example.
VBE's OS requests are intended to replace the need for the EFI 'boot-time services'. This works via a 'stub' which runs before Linux, collects the information from U-Boot, writes it to the device tree (mostly) and then jumps to Linux with the updated device tree.
Rather than just jumping into Linux and waiting for it to request things from U-Boot, we can look at the requests in the FIT and process them before jumping to Linux. This is simpler and easier to test. It is also more deterministic, since we can tell whether we might lack something needed by Linux, before jumping to it.
This series adds initial support for OS requests, with just a few simple ones provided. Further work will expand these out.
Simon Glass (14): dm: core: Avoid registering an invalid tree in oftree_ensure() bootm: Change incorrect 'unsupported' error bootm: Avoid returning error codes from command bootm: Drop #ifdef from do_bootm() boot: Correct handling of addresses in boot_relocate_fdt() fs: Quieten down the filesystems more fdt: Show a message when the working FDT changes bootstd: Move VBE setup into a shared function sandbox: Support FDT fixups boot: Pass the correct FDT to the EVT_FT_FIXUP event boot: Tidy up logging and naming in vbe_simple test: Move common FIT code into a separate fit_util file vbe: Add fixups for a basic set of OS requests vbe: Add a test for VBE device tree fixups
arch/sandbox/lib/bootm.c | 17 +++ boot/Makefile | 2 +- boot/bootm.c | 2 +- boot/image-fdt.c | 37 ++--- boot/vbe_fixup.c | 233 +++++++++++++++++++++++++++++ boot/vbe_simple.c | 16 +- cmd/bootm.c | 25 ++-- cmd/fdt.c | 1 + configs/sandbox_flattree_defconfig | 2 +- disk/part_efi.c | 15 +- doc/develop/vbe.rst | 3 +- doc/usage/cmd/fdt.rst | 1 + drivers/core/ofnode.c | 2 +- fs/btrfs/disk-io.c | 7 +- fs/ext4/ext4_common.c | 2 +- fs/fs_internal.c | 3 +- test/boot/Makefile | 1 + test/boot/bootflow.c | 2 + test/boot/bootstd_common.c | 49 ++++++ test/boot/bootstd_common.h | 16 ++ test/boot/vbe_fixup.c | 59 ++++++++ test/boot/vbe_simple.c | 34 +---- test/cmd/fdt.c | 11 +- test/py/tests/fit_util.py | 93 ++++++++++++ test/py/tests/test_event_dump.py | 1 + test/py/tests/test_fit.py | 79 ++-------- test/py/tests/test_vbe.py | 123 +++++++++++++++ 27 files changed, 681 insertions(+), 155 deletions(-) create mode 100644 boot/vbe_fixup.c create mode 100644 test/boot/vbe_fixup.c create mode 100644 test/py/tests/fit_util.py create mode 100644 test/py/tests/test_vbe.py