Message-ID: <1362386776.2943.11.camel@sauron>
Subject: Re: [PATCH V3 1/3] mtd: add new fields to nand_flash_dev{}
From: Artem Bityutskiy <dedekind1@gmail.com>
Reply-To: dedekind1@gmail.com
To: Huang Shijie <b32955@freescale.com>
Cc: Huang Shijie <shijie8@gmail.com>, dwmw2@infradead.org,
        computersforpeace@gmail.com, linux-mtd@lists.infradead.org,
        linux-kernel@vger.kernel.org
Date: Mon, 04 Mar 2013 10:46:16 +0200
In-Reply-To: <51345DFA.7070601@freescale.com>
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On Mon, 2013-03-04 at 16:40 +0800, Huang Shijie wrote:
> 于 2013年03月04日 16:24, Artem Bityutskiy 写道:
> > On Mon, 2013-03-04 at 16:08 +0800, Huang Shijie wrote:
> >> 于 2013年03月04日 15:50, Artem Bityutskiy 写道:
> >>> On Mon, 2013-03-04 at 13:57 +0800, Huang Shijie wrote:
> >>>> The current code uses the @id to store the device id(byte 1).
> >>>> But if we use the 8 bytes id data as the keyword, and expand the @id
> >>>> field to 8byte array,
> >>>> the device id is the second byte now. All the added zeros are for the
> >>> I do not think you need to store the full array of ID's. Device ID's for
> >>> all the 4 of above chips are different, which is enough to distinguish
> >>> between them.
> >>>
> >>> The only thing you need to add is the OOB size field to 'struct
> >>> nand_flash_dev'.
> >>>
> >> If i only add the oob size field. There will be two items with the same
> >> Device ID in nand_flash_ids table,
> >> one has oob_size, one does not have. such as:
> >>
> >>      {"NAND 8GIB 3,3V 8-bit", 0xDE, 0, 8192, 0, LP_OPTIONS},
> > Do you know what is this chip?
> this maybe not just a nand chip, it may stands for a class of nand chips.
> Toshiba may uses this device id, Micron may also uses it.
> 
> In other word, this item may stands for many nand chips.
> >>      {"NAND 8GIB 3,3V 8-bit", 0xDE, 0, 8192, 0, LP_OPTIONS, 640},   //OOB
> >> size is 640
> > So there are really 2 different chips with the same device id and
> > different OOB size? If you had 2 datasheets for me demonstrating this,
> > I'd be grateful.
> Please see the http://www.linux-mtd.infradead.org/nand-data/nanddata.html
> The ST's NAND08GW3B2C and Numonyx's NAND08GW3F2B share the same device 

Thanks, I forgot we have this great table. BTW, please, do not forget to
update it with information about these 4 chip you are adding,
irrespective of the solution we end up with.

-- 
Best Regards,
Artem Bityutskiy

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