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From: voice.shen@atmel.com (Bo Shen)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] mtd: atmel_nand: make ecc parameters same as definition
Date: Wed, 11 Jun 2014 11:24:41 +0800	[thread overview]
Message-ID: <5397CBF9.800@atmel.com> (raw)
In-Reply-To: <53958CCE.5080307@atmel.com>

Hi Josh,

On 06/09/2014 06:30 PM, Josh Wu wrote:
> Hi, Bo
>
> Thanks for the patch.
>
> On 6/6/2014 4:02 PM, Bo Shen wrote:
>> If the ecc parameter is not the same as definition, when the
>> mtd core check these parameters, it will give the unexpected
>> result.
> Could you be more specific to tell what kind of result will happened?

For example:
When try to calculate how many bits can correct in one page according to 
the definition, it will give the wrong result.

one page correct bits = (mtd->writesize * ecc->strength) / ecc->size;

take the following use case as an example:
mtd->writesize = 2048 bytes,
ecc->strength = 4 bytes, (for 512 bytes)

before this patch, the ecc->size = 2048, so the result is 4 bytes.

after this patch, the ecc->size = 512, so the result is 16 bytes.

The maximum correct bytes is 16 bytes while not 4 bytes. So, if not align

Best Regards,
Bo Shen

  reply	other threads:[~2014-06-11  3:24 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-06  8:02 [PATCH] mtd: atmel_nand: make ecc parameters same as definition Bo Shen
2014-06-09 10:30 ` Josh Wu
2014-06-11  3:24   ` Bo Shen [this message]
2014-06-12  7:20     ` Josh Wu
2014-06-12  7:26       ` Nicolas Ferre
2014-06-12  7:45         ` Bo Shen

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