Add support for starting TFA from U-Boot running in EL3 as part of
fitImage boot, so the user can start U-Boot in the highest privilege
level on the platform, bundle TFA, Linux, DT into a single fitImage
and boot such a bundle as a whole.

There are two main benefits of this approach. First is the ability
to run U-Boot in EL3, where it has unrestricted access to the entire
system and can act as a useful debug tool, as it was always intended
to be used. Second is the ability to easily and safely update of any
component in the fitImage, be it TFA, Linux or DT.

The boot process is similar to regular Linux with DT fitImage boot
process, except the TFA has to be bundled into the fitImage. For the
bundling instructions, see below. The TFA is started as a 'loadables'
with custom U_BOOT_FIT_LOADABLE_HANDLER and armv8_switch_to_el2_prep()
handling implemented in board code, and performing the handoff and
boot in case the TFA was loaded.

The loadables handler is optional and meant to set up any sort of
handoff structures used by the TFA BL31 or perform any other setup
that is needed by the blob. The custom armv8_switch_to_el2_prep()
has to implement the jump to TFA BL31 with return to U-Boot just
before booting the Linux kernel.

Example fitImage image and configuration section:

/dts-v1/;

/ {
    description = "Linux kernel with FDT blob and TFA BL31";

    images {
        kernel-1 { ... };
        fdt-1 { ... };
        atf-1 {                  /* This is the TFA BL31 image */
            description = "TFA BL31";
            data = /incbin/("../build/plat/release/bl31.bin");
            type = "tfa-bl31";
            arch = "arm64";
            os = "arm-trusted-firmware";
            compression = "none";
            load = <0x46400000>;
            entry = <0x46400000>;
        };
    };

    configurations {
        default = "conf-1";
        conf-1 {
            description = "Boot Linux";
            kernel = "kernel-1";
            fdt = "fdt-1";
            loadables = "atf-1"; /* This is the TFA BL31 loadable */
        };
    };
};

Reviewed-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>

Simon Glass <sjg@chromium.org> says:

The current UPL spec[1] has been tidied up and improved over the last
year, since U-Boot's original UPL support was written.

This series includes some prerequisite patches needed for the real UPL
patches. It is split from [2]

[1] https://github.com/UniversalPayload/spec/tree/3f1450d
[2] https://patchwork.ozlabs.org/project/uboot/list/?series=438574&state=*

Link: https://lore.kernel.org/r/20250111000029.245022-1-sjg@chromium.org

This function is really just getting the data. The size comes along for
the ride. In fact this function is only reliable way to obtain the data
for an image in a FIT, since the FIT may use external data.

Rename it to fit_image_get_data()

Signed-off-by: Simon Glass <sjg@chromium.org>

This function can only be used with FITs that use embedded data. Rename
it so this is clear.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

Simon Glass <sjg@chromium.org> says:

This includes various patches towards implementing the VBE abrec
bootmeth in U-Boot. It mostly focuses on SPL tweaks and adjusting what
fatures are available in VPL.

Link: https://lore.kernel.org/r/20241219182907.2609704-1-sjg@chromium.org

When the best-match feature fails to find something, use the provided
config name as a fallback. The allows SPL to select a suitable config
when best-match is enabled.

Signed-off-by: Simon Glass <sjg@chromium.org>

This function exists but is not exported. Add a prototype so it can be
used elsewhere.

Signed-off-by: Simon Glass <sjg@chromium.org>

When the initialisation vector is randomly generated, its value shall be
stored in the FIT together with the encrypted data. The changes allow to
store the IV in the FIT also in the case where the key is not stored in
the DTB but retrieved somewhere else at runtime.

Signed-off-by: Paul HENRYS <paul.henrys_ext@softathome.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

This reverts commit 1fdf53ace13f745fe8ad4d2d4e79eed98088d555, reversing
changes made to e5aef1bbf11412eebd4c242b46adff5301353c30.

I had missed that this caused too much size growth on rcar3_salvator-x.

Signed-off-by: Tom Rini <trini@konsulko.com>

When the best-match feature fails to find something, use the provided
config name as a fallback. The allows SPL to select a suitable config
when best-match is enabled.

Signed-off-by: Simon Glass <sjg@chromium.org>