From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Wed, 26 Mar 2014 12:55:02 +0100
From: Lothar =?UTF-8?B?V2HDn21hbm4=?= <LW@KARO-electronics.de>
To: Huang Shijie <b32955@freescale.com>
Subject: Re: [PATCHv2 1/1] mtd: gpmi: make blockmark swapping optional
Message-ID: <20140326125502.0e8d0657@ipc1.ka-ro>
In-Reply-To: <5332AEE7.2040402@freescale.com>
References: <532BCFCC.4080205@freescale.com>
 <1395399017-19005-1-git-send-email-LW@KARO-electronics.de>
 <20140324095902.GB11377@localhost>
 <20140326095156.3e5585b8@ipc1.ka-ro>
 <5332AEE7.2040402@freescale.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Cc: Fabio Estevam <fabio.estevam@freescale.com>,
 Mark Rutland <mark.rutland@arm.com>,
 Brian Norris <computersforpeace@gmail.com>,
 Russell King <linux@arm.linux.org.uk>, Pawel Moll <pawel.moll@arm.com>,
 Arnd Bergmann <arnd@arndb.de>, Ian Campbell <ijc+devicetree@hellion.org.uk>,
 Artem Bityutskiy <artem.bityutskiy@linux.intel.com>, linux-doc@vger.kernel.org,
 linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
 Rob Herring <robh+dt@kernel.org>, linux-mtd@lists.infradead.org,
 Shawn Guo <shawn.guo@freescale.com>, Rob Landley <rob@landley.net>,
 Kumar Gala <galak@codeaurora.org>, Shawn Guo <shawn.guo@linaro.org>,
 David Woodhouse <dwmw2@infradead.org>, Sascha Hauer <kernel@pengutronix.de>,
 linux-arm-kernel@lists.infradead.org
List-Id: Linux MTD discussion mailing list <linux-mtd.lists.infradead.org>
List-Unsubscribe: <http://lists.infradead.org/mailman/options/linux-mtd>,
 <mailto:linux-mtd-request@lists.infradead.org?subject=unsubscribe>
List-Archive: <http://lists.infradead.org/pipermail/linux-mtd/>
List-Post: <mailto:linux-mtd@lists.infradead.org>
List-Help: <mailto:linux-mtd-request@lists.infradead.org?subject=help>
List-Subscribe: <http://lists.infradead.org/mailman/listinfo/linux-mtd>,
 <mailto:linux-mtd-request@lists.infradead.org?subject=subscribe>

Hi,

Huang Shijie wrote:
> =E4=BA=8E 2014=E5=B9=B403=E6=9C=8826=E6=97=A5 16:51, Lothar Wa=C3=9Fmann =
=E5=86=99=E9=81=93:
> > I don't see why this should not be supported on i.MX28 (i.MX23 doesn't
> > do byteswapping anyway, so this wouldn't change anything for i.MX23).
> > The partitions used by Linux need not necessarily be accessible for the
> > Boot ROM code (and vice versa).
> But the first partition used to store the u-boot is accessible for the RO=
M.
>=20
Whether this partition is available to Linux depends on the partition table
passed in the DT.

> Please see "Figure 12-13" in the 12.12.1.12:
>    "In order to preserve the BI (bad block information), flash updater=20
> or gang programmer
> applications need to swap Bad Block Information (BI) data to byte 0 of=20
> metadata area for
> every page before programming NAND Flash. ROM when loading firmware,=20
> copies back
> the value at metadata[0] to BI offset in page data. The following figure=
=20
> shows how the
> factory bad block marker is preserved."
>=20
The inspection of the BB markers is only a fallback for the case that
there is no DBBT. From the same chapter that you quoted above:
| ROM uses DBBT to skip any bad block that falls within firmware data
| on NAND Flash device.
| If the address of DBBT Search Area in FCB is 0, ROM will rely on
| factory marked bad block markers to find out if a block is good or bad.

Thus, even the boot ROM of i.MX28 can well live without blockmark
swapping.


Lothar Wa=C3=9Fmann
--=20
___________________________________________________________

Ka-Ro electronics GmbH | Pascalstra=C3=9Fe 22 | D - 52076 Aachen
Phone: +49 2408 1402-0 | Fax: +49 2408 1402-10
Gesch=C3=A4ftsf=C3=BChrer: Matthias Kaussen
Handelsregistereintrag: Amtsgericht Aachen, HRB 4996

www.karo-electronics.de | info@karo-electronics.de
___________________________________________________________