So far only VBE-simple is implemented in U-Boot. This supports a single
image which can be updated in situ.

It is often necessary to support two images (A and B) so that the board
is not bricked if the update is interrupted or is bad.

In some cases, a non-updatable recovery image is desirable, so that the
board can be returned to a known-good state in the event of a serious
failure.

Introduce ABrec which provides these features. It supports three
independent images and the logic to select the desired one on boot.

While we are here, fix a debug message to indicate the function it
called. Provide a maintainers entry for VBE.

Note that fwupdated only supports VBE-simple so far, but supports for
ABrec will appear in time.

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

When VBE operates within VPL it does not want the FDT to be changed.
Provide a way to disable this feature.

Move the FIT_IMAGE_TINY condition out of spl_fit_record_loadable() so
that both conditions are together. This makes the code easier to
understand.

Replace the existing fit_loaded member, which is no-longer used.

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

Join the comment block for the fit_image_load() call back to where it
should be. Also fix a debug statement.

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

For a sandbox implementation, where code size is no object, it makes sense
to use the full bootstd drivers to load images.

For real boards, running from SRAM, this adds quite a bit of overhead.

Add a way to load the next phase using just the underlying storage
driver, to reduce code size. For now, only MMC is supported.

Change the log_debug() to show the load address and size in a more
neutral way, rather than suggesting that the load has already happened.

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

VBE needs to load different images from a FIT depending on the xPL phase
in use. The IH_PHASE value is used to select the image to load.

Add the required logic to handle this. For compatibility with the
SPL-loader driver, fill out a struct spl_image_info with the details
needed to boot the next phase.

This is good enough for VBE-simple but ABrec will need the full set of
bootstd features. So add a USE_BOOTMETH define to control this.

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

Add FDT support so that this can be copied down in memory after loading
and made available to the new image.

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

In many cases the FIT includes a devicetree. Add support for loading
this into a suitable place in memory.

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

In some cases only the 'loadable' property is present in the FIT.
Handle this by loading the first such image.

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

There is no guarantee that an FIT image starts on a block boundary. When
it doesn't, the image starts part-way through the first block.

Add logic to detect this and copy the image down into place.

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

This function can read fewer blocks than requested, so update the checks
to handle this.

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