From mboxrd@z Thu Jan  1 00:00:00 1970
From: moore@free.fr (Chris Moore)
Date: Mon, 14 Apr 2014 04:10:31 +0200
Subject: [PATCH 23/29] ARM: orion5x: use DT to describe NOR on edmini_v2
In-Reply-To: <20140413174513.2e39a55c@skate>
References: <1397400006-4315-1-git-send-email-thomas.petazzoni@free-electrons.com>
 <1397400006-4315-24-git-send-email-thomas.petazzoni@free-electrons.com>
 <20140413153150.GD10033@lunn.ch> <20140413174513.2e39a55c@skate>
Message-ID: <534B4397.2000500@free.fr>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Hi,

Le 13/04/2014 17:45, Thomas Petazzoni a ?crit :
> Dear Andrew Lunn,
>
> On Sun, 13 Apr 2014 17:31:50 +0200, Andrew Lunn wrote:
>
>>> -/*****************************************************************************
>>> - * 512KB NOR Flash on BOOT Device
>>> - ****************************************************************************/
>>> -
>>> -/*
>>> - * Currently the MTD code does not recognize the MX29LV400CBCT as a bottom
>>> - * -type device. This could cause risks of accidentally erasing critical
>>> - * flash sectors. We thus define a single, write-protected partition covering
>>> - * the whole flash.
>>> - * TODO: once the flash part TOP/BOTTOM detection issue is sorted out in the MTD
>>> - * code, break this into at least three partitions: 'u-boot code', 'u-boot
>>> - * environment' and 'whatever is left'.
>>> - */
>> Hi Thomas
>>
>> Did you check if this is still true? If it is fixed, maybe now would
>> be a good time to swap to three partitions?
> I don't know, and since the NOR contains the bootloader, and I'm not
> sure those Orion devices support UART booting, I clearly don't want to
> play too much with NOR writing, as I don't want to brick the only two
> Orion platforms that I have. So I'd prefer to leave the functionality
> as it was, and leave it to other more adventurous and interested people
> the work on improving this.
>

I subsequently added a fixup todrivers 
<http://lxr.free-electrons.com/source/drivers/>/mtd 
<http://lxr.free-electrons.com/source/drivers/mtd/>/chips 
<http://lxr.free-electrons.com/source/drivers/mtd/chips/>/cfi_cmdset_0002.c 
to correct top/bottom detection for many Macronix devices including the 
MX29LV400CBCT.
(Commit 87e92c062b19eea6054532f8143a91242f104a6f see 
http://lists.infradead.org/pipermail/linux-mtd/2008-October/023307.html)

Like Thomas, I was afraid of bricking my device so I didn't dare to 
modify and test the partitioning.
(Unfortunately I don't have working JTAG.)

Cheers,
Chris