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 for linux-mtd@lists.infradead.org; Wed, 18 Mar 2015 10:03:49 +0000
From: Boris Brezillon <boris.brezillon@free-electrons.com>
To: Andrea Marson <andrea.marson@dave.eu>
Subject: Re: RFC: detect and manage power cut on MLC NAND (linux-mtd Digest,
 Vol 144, Issue 70)
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Cc: Andrea Scian <rnd4@dave-tech.it>,
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Date: Wed, 18 Mar 2015 10:03:55 -0000

On Wed, 18 Mar 2015 10:56:15 +0100
Andrea Marson <andrea.marson@dave.eu> wrote:

> >
> > IIUC, you want to select SLC/MLC mode on a per-partition basis, that
> > should be feasible, and this would be particularly useful for bootloader
> > partitions (where UBI is not involved).
> That's exactly what I was thinking about.
> However it is still not clear to me how this should be implemented. I 
> have read a datasheet saying that "SLC mode" consists of halving block 
> addresses, that is higher bit of block address lines must be set to low. 
> I wonder if this strategy prevents paired page related issues. I think 
> one should work at page addressing level instead, in order to use pages 
> that are not paired only. Do you think it makes sense?

Yes, actually implementing the SLC mode in software is quite easy, the
only thing we need is a description of which pages are paired together
in a block.
Moreover, by doing that in SW we won't have to deal with each vendor
implementation of "SLC mode".



-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com