From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from top.free-electrons.com ([176.31.233.9]
 helo=mail.free-electrons.com)
 by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux))
 id 1WDDtv-0003p0-DZ
 for linux-mtd@lists.infradead.org; Tue, 11 Feb 2014 14:01:28 +0000
Date: Tue, 11 Feb 2014 11:01:03 -0300
From: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
To: Boris BREZILLON <b.brezillon.dev@gmail.com>
Subject: Re: [RFC PATCH] mtd: add per NAND partition ECC config
Message-ID: <20140211140102.GB23150@localhost>
References: <1391855206-5974-1-git-send-email-b.brezillon.dev@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <1391855206-5974-1-git-send-email-b.brezillon.dev@gmail.com>
Cc: linux-mtd@lists.infradead.org,
 Maxime Ripard <maxime.ripard@free-electrons.com>,
 Brian Norris <computersforpeace@gmail.com>,
 David Woodhouse <dwmw2@infradead.org>, linux-kernel@vger.kernel.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 Boris,

On Sat, Feb 08, 2014 at 11:26:46AM +0100, Boris BREZILLON wrote:
> This patch aims to add per partition ECC config for NAND devices.
> It defines a new field in the mtd struct to store the mtd ECC config and
> thus each mtd partition device can store its config instead of using the
> default NAND chip config.
> 
> This feature is needed to support the sunxi boot0 paritition case:
> Allwinner boot code (BROM) requires a specific HW ECC for its boot code
> that may not fit the HW NAND requirements for the entire NAND chip.
> 
> Signed-off-by: Boris BREZILLON <b.brezillon.dev@gmail.com>
> ---
> Hello,
> 
> This patch is just a draft that implement per partition ECC config.
> It's currently not properly splitted (it should be separated in several
> patches) and not documented either.
> 

Ah, ah...

> There's at least one point that bother me in the current implementation:
> I introduced DT notions in the nand core code by the mean of the get_ecc_ctrl
> callback, and so far this was kept out of mtd/nand core code (I guess it was
> on purpose).
> 
> Please let me know if you see other drawbacks.
> 
> If you think per partition ECC should not be implemented, could you help me
> find a way to handle sunxi specific case decribed above ?
> 
>  drivers/mtd/mtdpart.c          |   23 ++-
>  drivers/mtd/nand/nand_base.c   |  428 ++++++++++++++++++++++++----------------

I really appreciate your effort, but 428 changed lines is a too big and
intrusive change. I must admit I'm not smart enough to review such patches.

I honestly think you'll have better luck getting feedback if you take the time
to properly split and document this.

Yeah, it's annoying and time-consuming, but it's globally cheaper for you to
invest time on making it easier for reviewers and maintainers, than for each
of us to invest the time deciphering this :-)

Just my point of view, of course.
-- 
Ezequiel García, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com