From: Tom Rini <trini@ti.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] Broken ecc.size when switching between sw and hw ecc (beagleboard)
Date: Mon, 5 Mar 2012 11:58:35 -0700 [thread overview]
Message-ID: <20120305185835.GG18051@bill-the-cat> (raw)
In-Reply-To: <4F4E9201.60502@freescale.com>
On Wed, Feb 29, 2012 at 03:00:49PM -0600, Scott Wood wrote:
> On 02/29/2012 06:12 AM, Orjan Friberg wrote:
> > For the beagleboard, ecc.size is not explicitly set when doing 'nandecc
> > sw'. If it's not set for the NAND_ECC_SOFT case in nand_scan_tail, it's
> > set to 256 bytes.
> >
> > When doing 'nandecc hw', ecc.size is set to 512 bytes. Hence, when
> > changing back to 'nandecc sw' ecc.size remains at 512 bytes and suddenly
> > the format has changed.
> >
> >
> > It seems the current nandecc command needs to set this explicitly, but
> > also needs to be augmented to be able to select the newly added 4/8-bit
> > BCH ECC.
>
> Yes, that looks like a bug in omap_nand_switch_ecc().
Correct. And wrt using the new 4/8/16-bit BCH library, that's what I
was starting on when I found the nand dump issue :)
> > But it also seems like nandecc selection should be more generic than for
> > omap3 (currently it lives in arch/arm/cpu/armv7/omap3/board.c).
>
> ECC mode is normally not something that you want to be runtime
> switchable, as changing it usually changes the on-flash format. It also
> requires driver cooperation -- the actual implementation (as opposed to
> the command-line wrapper) is in drivers/mtd/nand/omap_gpmc.c.
There is unfortunately a long-running saga here and what we have now is
what we have for a number of existing platforms. Moving forward, things
are better and there's an argument at least for not making ECC mode
switching a run-time command.
--
Tom
prev parent reply other threads:[~2012-03-05 18:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-29 12:12 [U-Boot] Broken ecc.size when switching between sw and hw ecc (beagleboard) Orjan Friberg
2012-02-29 21:00 ` Scott Wood
2012-03-01 9:17 ` Orjan Friberg
2012-03-01 17:32 ` Scott Wood
2012-03-02 8:39 ` Orjan Friberg
2012-03-05 18:58 ` Tom Rini [this message]
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