[yocto] SDK-only build

[Trevor Woerner]

Hi Khem,

Thanks for adding your thoughts; you were exactly who I was hoping
would have input to my question :-)

On Fri, Mar 8, 2013 at 3:59 AM, Khem Raj <raj.khem at gmail.com> wrote:
>> Sometimes I like to work with a "sub-Linux" device, something that is
>> too small to run Linux, or a device on which, for whatever reason,
>> I've decided I don't want to run Linux.
>
> However adding a pure bare metal
> SDK generation is a whole different story and may be out of scope here
>
>> I've been wondering lately if, theoretically, it would be possible to
>> use yocto to create a development environment for such projects
>> (specifically an SDK).

I watched the video of your presentation a couple years ago at some
ELC(E?) where you discussed using Yocto to generate an SDK. That
presentation struck a chord with me because I know exactly how I would
use such an SDK. I knew, of course, of using Yocto to create a Linux
distribution, and I was aware of creating a -dev form of that
distribution for doing development on the target, but I wasn't aware
of the SDK option for putting together the -native programs, sysroot,
and cross-development tools for independent development for a given
distribution.

I recently started working with a Cortex-M4 based device. Knowing that
simply pushing my code to github wasn't going to help many people
unless I provided instructions on how to setup an environment to work
with the code and the device, I wrote a script that aims to easily
setup someone's environment to be the same as mine. Setting up an
environment involves generating cross-development tools, building a
set of native tools which are used with the device (for example some
sort of flash programmer or openOCD), and having a sysroot-like area
populated with libraries, linker scripts, and header files specific to
the device which the cross-development tools can find without
requiring any -L and -I options.

The whole time I was writing my script I couldn't help think to myself
how nice it would be to be able to write recipes instead of a script,
how nice it would be to make use of bitbake's fetchers, and the
ability to apply patches etc., and then have that all wrapped up into
a nice, self-extracting SDK! Why re-invent the wheel?

Somehow I can't help think this could/should be possible. I can
perform all the necessary steps by hand, but when I consider using
OE/Yocto I feel a bit overwhelmed. Maybe all I need is just bitbake?