[U-Boot] [PATCH 7/7] tegra: seaboard: disable SPI, move environment to eMMC

[Stephen Warren <swarren@wwwdotorg.org>]

On 05/31/2012 05:39 PM, Simon Glass wrote:
> Hi Stephen,
> 
> On Thu, May 24, 2012 at 2:38 PM, Stephen Warren <swarren@wwwdotorg.org
> <mailto:swarren@wwwdotorg.org>> wrote:
> 
>     From: Stephen Warren <swarren at nvidia.com <mailto:swarren@nvidia.com>>
> 
> 
> Acked-by: Simon Glass <sjg at chromium.org <mailto:sjg@chromium.org>>
> 
> But a question - what happens if we have a partition table and
> filesystems on the eMMC - i.e. if we are not actually booting from eMMC?

The eMMC is divided into:

* Boot block 0, 512K
* Boot block 1, 512K
* Main area, the rest

This patch stores the environment at the end of boot block 1.

The Linux kernel sees each of those 3 areas as separate block devices
(and indeed the 2 boot blocks are read-only by default and require sysfs
writes to enable writing). As such, any partition table etc. would be
confined to the main area. So, there should be no conflict between PT/FS
and saved environment.

SD cards don't have these separate areas, and it may even be optional on
eMMC. Still, the Seaboard/Springbank eMMC has these separate blocks.