Kernel 3.10.31 and SD card numbering and boot scripts

[Eric Nelson <eric.nelson@boundarydevices.com>]

Hi all,

The 3.10.31 kernel contains a nifty bit of code from Sascha Hauer
that addresses the question of SD card numbering (device naming)
quite well:

	http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/commit/drivers/mmc/card/block.c?h=imx_3.10.31_1.1.0_beta&id=5f9447e5d97060207c4742d5a06e5548de45972d
	https://www.mail-archive.com/linux-mmc@vger.kernel.org/msg26472.html

Unfortunately, it also changes the requirements for the kernel
command-line and breaks our boot scripts.

This is probably a good time to ask a related question about
where we're keeping boot scripts.

We have been compiling boot scripts out of our U-Boot tree
from a Yocto-specific "6x_bootscript-yocto.txt" that implements
the conventions of the Freescale Community BSP (kernel in
the root of partition 1 and rootfs in partition 2).

Since boot scripts have dependencies on a lot of things, it's
not clear to me that they belong in the U-Boot source tree
and that a Yocto-specific boot script really belongs directly
in the Yocto tree somewhere.

Since a Yocto build knows about the PREFERRED_VERSION of the
kernel, it would be straightforward to have multiple versions
of a boot script.

Otherwise, we'd need to place a couple of versions in the
U-Boot tree:
	6x_bootscript-yocto.txt
	6x_bootscript-yocto-after-3.10.17.txt
and we'd also need some logic in u-boot-script-boundary.bb
to choose between them.

Before crafting a patch to do this, I'd like to get some feedback.

Regards,


Eric