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From: Juergen Beisert <jbe@pengutronix.de>
To: linux-mtd@lists.infradead.org
Cc: "Fabio Estevam" <fabio.estevam@freescale.com>,
	"javier Martin" <javier.martin@vista-silicon.com>,
	"Gaëtan Carlier" <gcembed@gmail.com>
Subject: Re: [1/1] mxc_nand : allow swapping the Bad block Indicator for NFC v1.
Date: Thu, 6 Sep 2012 12:44:01 +0200	[thread overview]
Message-ID: <201209061244.02071.jbe@pengutronix.de> (raw)
In-Reply-To: <504871AF.7040809@gmail.com>

Gaëtan Carlier wrote:
> Hi Javier,
>
> On 09/06/2012 11:14 AM, javier Martin wrote:
> > Hi Gaëtan,
> > has this behavior been documented by Freescale anywhere?

There is an application note available 
called "FSL_AppNote_Nand_Flash_Bad_Block_Management_for_Linux_BSP.pdf"
which describes the behaviour.

After reading a page from NAND into the internal NFC's SRAM, the data layout 
looks like:

SRAM Offset               real NAND's Data
---------------- SRAM data area ---------------------
  0
  .                     [   0 ...  511] 512 Byte page data
 511
 512
  .                     [ 528 ... 1039] 512 Byte page data
1023
1024
  .                     [1056 ... 1567] 512 Byte page data
1535
1536
  .                     [1584 ... 2047] 464 Byte page data
1999
2000
  .                     [   0 ...   47] 48 Byte OOB data
2047

-------------- SRAM OOB area ----------------------------
2048     0x800
  .                     [ 512 ...  527] 16 Byte page data
2063
2064     0x810
  .                     [1040 ... 1055] 16 Byte page data
2079
2080     0x820
  .                     [1568 ... 1583] 16 Byte page data
2095
2096     0x830
  .                     [  48 ...   63] 16 Byte OOB data
2112

> > Furthermore, what I can't guess is where that 0x7D0 comes from. I know
> > Jürgen described something related to the spare area being mixed with
> > the data (main) area but, is there any documentation about it we can
> > check?

See the table above: if you are interested in the byte at offset 0 in the 
NAND's OOB area, you must read the byte at offset 2000 (= 0x7D0) in the SRAM 
area instead.

Regards,
Juergen

-- 
Pengutronix e.K.                              | Juergen Beisert             |
Linux Solutions for Science and Industry      | Phone: +49-5121-206917-5128 |
Vertretung Sued/Muenchen, Germany             | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686              | http://www.pengutronix.de/  |

  reply	other threads:[~2012-09-06 10:45 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CACKLOr0zCCZ0WNpGiOOvoUk4s_vR5Ls4aw6PhXDoYeNQFTESgQ@mail.gmail.com>
2012-09-06  9:49 ` [1/1] mxc_nand : allow swapping the Bad block Indicator for NFC v1 Gaëtan Carlier
2012-09-06 10:44   ` Juergen Beisert [this message]
2012-09-06 10:57   ` Juergen Beisert
2012-09-06 11:07     ` Juergen Beisert
2012-09-06 11:31       ` javier Martin
2012-09-10 13:22   ` Juergen Beisert

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