[yocto] SPL_IMAGE, SPL_BINARY, and SPL_SYMLINK definitions

[Denys Dmytriyenko]

On Mon, Nov 25, 2013 at 01:02:35PM -0500, William Mills wrote:
> On 11/25/2013 09:06 AM, Rifenbark, Scott M wrote:
> >Anyone have descriptions for these three variables?  I would like to 
> >document them and am wondering if anyone has used them or knows how they 
> >work.

git blame u-boot.inc would have shown the commit 2965aa2f that added those 
vars into the main u-boot.inc. The commit log does provide some explanation. 
Although, that is the commit that unified SPL_* vars into a common .inc file, 
previously we used to add them into specific u-boot_*.bb recipes along with 
the necessary do_install_append() and do_deploy_append()...


> SPL is the preloader for U-boot required on some platforms.

And it stands for Secondary Program Loader:
http://git.denx.de/?p=u-boot.git;a=blob;f=doc/README.SPL;hb=HEAD


> The base include for u-boot defines the SPL_IMAGE and SPL_SYMLINK
> http://git.yoctoproject.org/cgit/cgit.cgi/poky/tree/meta/recipes-bsp/u-boot/u-boot.inc
> 
> One example of use of SPL_BINARY is here:
> http://git.yoctoproject.org/cgit/cgit.cgi/meta-ti/tree/recipes-bsp/u-boot/u-boot_2011.12.bb
> 
> So the SPL_BINARY defines the name of the file in the filesystem image.
> The SPL_IMAGE and SPL_SYMLINK appear to specific the long version
> specific image file produced by the build and the somewhat shorter
> symlink that points to it.  These will be in a machine specific dir
> on the build machine; the same place the kernel is found.
> (The kernel also gets a very long name and a symlink  you can reuse
> wording from the description if you have that already.)
>