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Date: Fri, 28 Oct 2011 12:40:03 +0200
From: Matthieu CASTET <matthieu.castet@parrot.com>
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To: Jon Povey <Jon.Povey@racelogic.co.uk>
Subject: Re: [RFC] Change ECC algorithm from userspace
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Cc: Enric Balletbo i Serra <eballetbo@iseebcn.com>,
	Javier Martinez Canillas <martinez.javier@gmail.com>,
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Jon Povey a écrit :
> linux-mtd-bounces@lists.infradead.org wrote:
>> I want to be able to use 1-bit ECC for the first partition where I
>> save the loader binary and has to be accessed by the ROM boot but use
>> a 4-bit ECC for my rootfs partition.
>>
>> Does anyone have this same issue?
> 
> DM355 and DM365 has similar issues as the RBL expects a different OOB/ECC
> layout to Linux.
> 
>> What is the best approach to store data in a NAND device using
>> different ECC techniques?
> 
> What I have done is write a utility that calculates ECC and writes to
> the mtd device in RAW mode. So to rewrite the bootloader I take care of
> the ECC and layout at application level without changing the kernel.
>
Note that the kernel raw mode doesn't write the page in one time : it write data
and then ecc. This may cause problem with NOP1 nand.

see http://lists.infradead.org/pipermail/linux-mtd/2010-August/031262.html


Matthieu