a complex map

Mike Frysinger vapier.adi at gmail.com
Mon Sep 8 15:23:11 EDT 2008

On Mon, Sep 8, 2008 at 2:44 PM, Allon Stern wrote:
> I've got the unique pleasure of dealing with a hardware design
> cramming a 64MB NOR flash onto a 23 bit address bus (Coldfire M5282).
> The memory chip is a Numonyx Strataflash (P30). It's a single part on
> a 16 bit data bus.
> A couple of questions:
> #1: this chip appears as two dies; Each die has four small (32K)
> blocks at the bottom, with 128K blocks elsewhere. Is this a problem,
> particularly if the small blocks appear in the middle of an MTD
> partition? I'm assuming no problem. (I have concatenating support
> enabled to allow my partition to span the two dies)

the mtd layers handle bottom/top boot devices just fine. usually
people use those sectors to store configurations or bootloaders rather
than filesystems though.  but that is of course your choice.

> #2: I control the high two address bits on the flash (A24 and A25)
> using GPIOs. I have a customized map for this flash which sets the
> GPIOs appropraitely for the offset being accessed. Is this is all I
> need to do?

ive written a generic gpio mapping driver but i'm not sure it's been
posted to LKML yet ... perhaps you will find it useful:

example platform resources can be found here:

and here:

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