From: Mike Dunn <mikedunn@newsguy.com>
To: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: linux-mtd@lists.infradead.org, dwmw2@infradead.org,
linux-kernel@vger.kernel.org, dedekind1@gmail.com
Subject: Re: [PATCH v2 07/16] mtd/docg3: add OOB layout to mtdinfo
Date: Sun, 13 Nov 2011 16:58:54 -0800 [thread overview]
Message-ID: <4EC067CE.4050805@newsguy.com> (raw)
In-Reply-To: <87vcqoiavr.fsf@free.fr>
On 11/13/2011 02:18 AM, Robert Jarzmik wrote:
> I took a different approach. I check an internal docg3 register to see if the
> page was written. Or I could had have checked the Hamming code, as I don't think
> it can be 0xff whatever the pagesize 7 bytes values.
>
> The reason behind is that the Hamming code is Ham(64, 57), ie. Ham(2^6,
> 2^6-6-1). The means the 6 bits are enough to cover all codewords possibilities,
> and 0xff is not one of them.
>
> So unless a bitflip in Hamming code, 0xff in it means blank page.
Clever!
> And I think
> the ECC engine is even smarter, with the ECCCONF1_PAGE_IS_WRITTEN.
I forgot about this. If the hardware can indeed tell you, I guess this is the
best way. Sounds like I'll be updating my blank page detection.
Mike
WARNING: multiple messages have this Message-ID (diff)
From: Mike Dunn <mikedunn@newsguy.com>
To: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: dwmw2@infradead.org, dedekind1@gmail.com,
linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 07/16] mtd/docg3: add OOB layout to mtdinfo
Date: Sun, 13 Nov 2011 16:58:54 -0800 [thread overview]
Message-ID: <4EC067CE.4050805@newsguy.com> (raw)
In-Reply-To: <87vcqoiavr.fsf@free.fr>
On 11/13/2011 02:18 AM, Robert Jarzmik wrote:
> I took a different approach. I check an internal docg3 register to see if the
> page was written. Or I could had have checked the Hamming code, as I don't think
> it can be 0xff whatever the pagesize 7 bytes values.
>
> The reason behind is that the Hamming code is Ham(64, 57), ie. Ham(2^6,
> 2^6-6-1). The means the 6 bits are enough to cover all codewords possibilities,
> and 0xff is not one of them.
>
> So unless a bitflip in Hamming code, 0xff in it means blank page.
Clever!
> And I think
> the ECC engine is even smarter, with the ECCCONF1_PAGE_IS_WRITTEN.
I forgot about this. If the hardware can indeed tell you, I guess this is the
best way. Sounds like I'll be updating my blank page detection.
Mike
next prev parent reply other threads:[~2011-11-14 0:00 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-10 8:05 [PATCH v2 00/16] DocG3 fixes and write support Robert Jarzmik
2011-11-10 8:05 ` Robert Jarzmik
2011-11-10 8:05 ` [PATCH v2 01/16] mtd/docg3: fix debug log verbosity Robert Jarzmik
2011-11-10 8:05 ` Robert Jarzmik
2011-11-10 8:05 ` [PATCH v2 02/16] mtd/docg3: fix tracing of IO in writeb Robert Jarzmik
2011-11-10 8:05 ` Robert Jarzmik
2011-11-10 8:05 ` [PATCH v2 03/16] mtd/docg3: fix protection areas reading Robert Jarzmik
2011-11-10 8:05 ` Robert Jarzmik
2011-11-10 8:05 ` [PATCH v2 04/16] mtd/docg3: fix BCH registers Robert Jarzmik
2011-11-10 8:05 ` Robert Jarzmik
2011-11-12 19:40 ` Mike Dunn
2011-11-12 19:40 ` Mike Dunn
2011-11-13 10:20 ` Robert Jarzmik
2011-11-13 10:20 ` Robert Jarzmik
2011-11-10 8:05 ` [PATCH v2 05/16] mtd/docg3: fix reading oob+data without correction Robert Jarzmik
2011-11-10 8:05 ` Robert Jarzmik
2011-11-10 8:05 ` [PATCH v2 06/16] mtd/docg3: add multiple floor support Robert Jarzmik
2011-11-10 8:05 ` Robert Jarzmik
2011-11-10 8:05 ` [PATCH v2 07/16] mtd/docg3: add OOB layout to mtdinfo Robert Jarzmik
2011-11-10 8:05 ` Robert Jarzmik
2011-11-12 19:39 ` Mike Dunn
2011-11-12 19:39 ` Mike Dunn
2011-11-13 10:18 ` Robert Jarzmik
2011-11-13 10:18 ` Robert Jarzmik
2011-11-13 12:53 ` Artem Bityutskiy
2011-11-13 12:53 ` Artem Bityutskiy
2011-11-13 13:03 ` David Woodhouse
2011-11-13 13:03 ` David Woodhouse
2011-11-13 13:35 ` Artem Bityutskiy
2011-11-13 13:35 ` Artem Bityutskiy
2011-11-13 16:38 ` Robert Jarzmik
2011-11-13 16:38 ` Robert Jarzmik
2011-11-13 19:55 ` Mike Dunn
2011-11-13 19:55 ` Mike Dunn
2011-11-13 20:27 ` Artem Bityutskiy
2011-11-13 20:27 ` Artem Bityutskiy
2011-11-14 18:08 ` Proposed change to mtd read functions (Was Re: [PATCH v2 07/16] mtd/docg3: add OOB layout to mtdinfo) Mike Dunn
2011-11-14 18:08 ` Mike Dunn
2011-11-14 17:38 ` Artem Bityutskiy
2011-11-14 17:38 ` Artem Bityutskiy
2011-11-14 0:58 ` Mike Dunn [this message]
2011-11-14 0:58 ` [PATCH v2 07/16] mtd/docg3: add OOB layout to mtdinfo Mike Dunn
2011-11-10 8:05 ` [PATCH v2 08/16] mtd/docg3: add registers for erasing and writing Robert Jarzmik
2011-11-10 8:05 ` Robert Jarzmik
2011-11-10 8:05 ` [PATCH v2 09/16] mtd/docg3: add OOB buffer to device structure Robert Jarzmik
2011-11-10 8:05 ` Robert Jarzmik
2011-11-10 8:05 ` [PATCH v2 10/16] mtd/docg3: add write functions Robert Jarzmik
2011-11-10 8:05 ` Robert Jarzmik
2011-11-10 8:05 ` [PATCH v2 11/16] mtd/docg3: add erase functions Robert Jarzmik
2011-11-10 8:05 ` Robert Jarzmik
2011-11-10 8:05 ` [PATCH v2 12/16] mtd/docg3: map erase and write functions Robert Jarzmik
2011-11-10 8:05 ` Robert Jarzmik
2011-11-10 8:05 ` [PATCH v2 13/16] mtd/docg3: add ECC correction code Robert Jarzmik
2011-11-10 8:05 ` Robert Jarzmik
2011-11-12 19:49 ` Mike Dunn
2011-11-12 19:49 ` Mike Dunn
2011-11-13 10:35 ` Robert Jarzmik
2011-11-13 10:35 ` Robert Jarzmik
2011-11-14 2:13 ` Mike Dunn
2011-11-14 2:13 ` Mike Dunn
2011-11-10 8:05 ` [PATCH v2 14/16] mtd/docg3: add suspend and resume Robert Jarzmik
2011-11-10 8:05 ` Robert Jarzmik
2011-11-10 8:05 ` [PATCH v2 15/16] mtd/docg3: add fast mode Robert Jarzmik
2011-11-10 8:05 ` Robert Jarzmik
2011-11-10 8:05 ` [PATCH v2 16/16] mtd/docg3: add protection areas sysfs access Robert Jarzmik
2011-11-10 8:05 ` Robert Jarzmik
2011-11-12 20:02 ` [PATCH v2 00/16] DocG3 fixes and write support Mike Dunn
2011-11-12 20:02 ` Mike Dunn
2011-11-13 10:41 ` Robert Jarzmik
2011-11-13 10:41 ` Robert Jarzmik
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