With global bootmeths we want to scan without a bootdev. Update the logic
to allow this.
Change the bootflow command to show the bootdev only when valid.
Signed-off-by: Simon Glass <sjg@chromium.org>
Avoid using 'count' to mean either a count or an error, since this is
confusing. In fact, the called function never return 0, since that is an
error.
Use 'ret' instead.
Signed-off-by: Simon Glass <sjg@chromium.org>
A 'bootdev' is a device which can be used to boot an operating system.
It is a child of the media device (e.g. MMC) which handles reading files
from that device, such as a bootflow file.
Add a uclass for bootdev and the various helpers needed to make it
work. Also add a binding file, empty for now.
Signed-off-by: Simon Glass <sjg@chromium.org>
