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Date: Mon, 4 Mar 2013 16:40:26 +0800
From: Huang Shijie <b32955@freescale.com>
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Subject: Re: [PATCH V3 1/3] mtd: add new fields to nand_flash_dev{}
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Cc: dwmw2@infradead.org, computersforpeace@gmail.com,
 Huang Shijie <shijie8@gmail.com>, linux-kernel@vger.kernel.org,
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=E4=BA=8E 2013=E5=B9=B403=E6=9C=8804=E6=97=A5 16:24, Artem Bityutskiy =E5=
=86=99=E9=81=93:
> On Mon, 2013-03-04 at 16:08 +0800, Huang Shijie wrote:
>> =E4=BA=8E 2013=E5=B9=B403=E6=9C=8804=E6=97=A5 15:50, Artem Bityutskiy =
=E5=86=99=E9=81=93:
>>> 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 th=
e
>>> 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 distinguis=
h
>>> 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 sam=
e
>> 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=20
id but with the
different oob size.

thanks
Huang Shijie