[U-Boot] [PATCH] Kbuild: allow building tools without board configuration

[Alexey Brodkin]

On Mon, 2014-03-31 at 11:31 -0400, Tom Rini wrote:
> On Mon, Mar 31, 2014 at 03:24:19PM +0000, Alexey Brodkin wrote:
> > Hi Tom,
> > 
> > On Mon, 2014-03-31 at 11:16 -0400, Tom Rini wrote:
> > > On Mon, Mar 31, 2014 at 05:33:51PM +0900, Masahiro Yamada wrote:
> > > 
> > > > Prior to Kbuild, U-Boot could build under tools/ directory
> > > > withour configuring for a specific board.
> > > > 
> > > > That feature was lost when switching to Kbuild.
> > > > 
> > > > This patch revives it again by adding a make target "tools-only".
> > > > 
> > > > Usage:
> > > >   $ make tools-only
> > > > 
> > > > Neither board configuration nor cross compiler are required to
> > > > build host tools.
> > > > 
> > > > Signed-off-by: Masahiro Yamada <yamada.m at jp.panasonic.com>
> > > > Suggested-by: Alexey Brodkin <Alexey.Brodkin at synopsys.com>
> > > > Cc: Alexey Brodkin <Alexey.Brodkin at synopsys.com>
> > > > Cc: Simon Glass <sjg at chromium.org>
> > > > Cc: Tom Rini <trini at ti.com>
> > > 
> > > Problem is that we make enabling the signature code (which adds more
> > > deps on the host) based on the config, and this was intentional.   So
> > > I'm not sure if we want to do this exactly, at least right now.
> > 
> > Could you please add a bit more clarifications for your comment.
> > 
> > I don't quite understand why do I need to have any info from a board
> > configuration when building "mkimage" utility.
> > 
> > Maybe I'm missing something.
> > 
> > And the problem is without proposed patch it's virtually impossible (or
> > I don't know how) to build "mkimage" without configuring the real board.
> > 
> > For example what Linux distros will do to build generic "mkimage" tool?
> 
> So, if you check out tools/mkimage.c you can see that if
> CONFIG_FIT_SIGNATURE is set we add options for doing rsa/etc signatures
> on parts of a FIT image (see doc/uImage.FIT/signature.txt).  But then
> you need to have crypto libraries on the host available for linking.
> When not set we capture the relevant flags and print out a message to
> stderr.  Since generic distros today hate FIT images even more than
> legacy images, I'm not overly concerned about that, today.

So why don't we accept proposed patch so at least there will be a simple
way to build generic "mkimage" people usually need?

If needed we may do more changes in the patch. For example we may add
warning message saying that FIT images won't be supported by this
"generic" "mkimage" etc.

-Alexey