Message-ID: <52E8D827.8010609@overkiz.com>
Date: Wed, 29 Jan 2014 11:29:59 +0100
From: boris brezillon <b.brezillon@overkiz.com>
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To: Brian Norris <computersforpeace@gmail.com>
CC: Maxime Ripard <maxime.ripard@free-electrons.com>,
        Rob Landley <rob@landley.net>, Russell King <linux@arm.linux.org.uk>,
        David Woodhouse <dwmw2@infradead.org>,
        Grant Likely <grant.likely@linaro.org>, devicetree@vger.kernel.org,
        linux-doc@vger.kernel.org, dev@linux-sunxi.org,
        linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org,
        Huang Shijie <b32955@freescale.com>
Subject: Re: [RFC PATCH 1/9] mtd: nand: retrieve ECC requirements from Hynix
 READ ID byte 4
References: <1389190924-26226-1-git-send-email-b.brezillon@overkiz.com> <1389190924-26226-2-git-send-email-b.brezillon@overkiz.com> <20140123014906.GY8919@ld-irv-0074>
In-Reply-To: <20140123014906.GY8919@ld-irv-0074>
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Sender: linux-kernel-owner@vger.kernel.org

Hello Brian,

On 23/01/2014 02:49, Brian Norris wrote:
> + Huang
>
> Hi Boris,
>
> On Wed, Jan 08, 2014 at 03:21:56PM +0100, Boris BREZILLON wrote:
>> The Hynix nand flashes store their ECC requirements in byte 4 of its id
>> (returned on READ ID command).
>>
>> Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
> I haven't verified yet (perhaps Huang can confirm?), but this may be
> similar to a patch Huang submitted recently. In his case, we found that
> this table is actually quite unreliable and is likely hard to maintain.

You mean these bytes are not reliable within the whole Hynix LP (Large Page)
NAND product line ?

>
> Why do you need this ECC information, for my reference?

Because the NAND flash available on the cubietruck board does not 
support the
ONFI standard, and I thought this could be a option to retrieve the ECC 
strength
requirements.

Anyway, I added a new helper function to retrieve ecc informations from 
device
tree (I'll post it in the 2nd version of this series). We'll see if this 
approach is
accepted...

>
> Brian

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