Combining multiple NAND MTDs

[Scott Wood]

On Tue, 5 Apr 2011 16:35:10 -0700
Barry G <mr.scada at gmail.com> wrote:

> I want to run UBIFS on the combined 2 gigs of flash.  Whats the best
> way to do this?
> 
> I tried using the mtdconcat stuff and wrote a small driver
> but I am not sure how to populate the mtd_info structure since do_probe_map
> doesn't work with NAND AFAIK.
> 
> I see that fsl_elbc_select_chip says "hardware does not seem to support this".
> Not sure if this is related.

It's not related -- it's talking about a single physical chip with
multiple chip selects, not a logical concatenation of multiple separate
devices.

> I see some comments in mtd-physmap.txt about using multiple reg ranges?
> Does this work with NAND?

No.

I don't know of an out-of-the-box configuration step you can take to do
mtdconcat of eLBC NAND, but you could try creating a custom map driver that
glues things together as you wish.  Or if you want to be more ambitious,
perhaps a kernel command line (or other dynamic config) option that lets you
glue arbitrary MTD devices together.

-Scott