Add more detail to the description of U-Boot boot phases:
* describe which steps are optional
* mentions alternative boot flows
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Now that Linux has accepted these tags, move U-Boot over to use them.
Tidy up the comments and formatting, making sure that VPL is mentioned
too.
Signed-off-by: Simon Glass <sjg@chromium.org>
Add support for VPL, a new phase of U-Boot. This runs after TPL. It is
responsible for selecting which SPL binary to run, based on a
verified-boot process.
Signed-off-by: Simon Glass <sjg@chromium.org>
