When the value of a text entry is not provided an execption is generated
talking about a None type. This is confusing. Add a more explanatory error
and a test for this case.
Signed-off-by: Simon Glass <sjg@chromium.org>
At present only the more complex entries are documented. It is useful to
have documentation for all entries in one place.
As a first step, add and expand the documentation to cover all entries.
Signed-off-by: Simon Glass <sjg@chromium.org>
It is useful to able to write an identifying string to the image within an
entry. Add a 'text' entry type to handle this. The actual text is
typically passed to binman on the command line. The text is not itself
nul-terminated but this can be achieved if required by setting the size of
the entry to something larger than the text.
Signed-off-by: Simon Glass <sjg@chromium.org>
