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From: Richard Weinberger <richard@nod.at>
To: KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp>
Cc: David Woodhouse <dwmw2@infradead.org>,
	Brian Norris <computersforpeace@gmail.com>,
	"linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] mtd: nand: support for Toshiba BENAND (Built-in ECC NAND)
Date: Tue, 16 Jun 2015 15:53:08 +0200	[thread overview]
Message-ID: <55802A44.6040708@nod.at> (raw)
In-Reply-To: <558025B7.3030103@toshiba.co.jp>

Am 16.06.2015 um 15:33 schrieb KOBAYASHI Yoshitake:
>>> +       /* correctable */
>>> +       else if (status & NAND_STATUS_RECOM_REWRT) {
>>> +               pr_info("BENAND : Recommended to rewrite!\n");
>>> +               bitflips = chip->ecc.strength;
>>
>> In your case this might be okay, as you set strength to 1.
>> Otherweise you'd have to report the real number of bitflips.
> 
> I also thought it is okay in this case.
> BENAND return corrected data to Host NAND Controller till uncorrectable status.
> The current patch uses this Read Status command 70h to abstract BENAND Multi
> bit ECC and Need to Rewrite judgement so BENAND would look like 1bit ECC device.

The layers above MTD need to know how many bits got repaired.
It seems like BENAND suffers from the same shortcomings than On-Die-ECC. ;-\
Please see my patches how to deal with that. Maybe you can find a better solution.

Thanks,
//richard


WARNING: multiple messages have this Message-ID (diff)
From: Richard Weinberger <richard@nod.at>
To: KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp>
Cc: "linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
	Brian Norris <computersforpeace@gmail.com>,
	David Woodhouse <dwmw2@infradead.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] mtd: nand: support for Toshiba BENAND (Built-in ECC NAND)
Date: Tue, 16 Jun 2015 15:53:08 +0200	[thread overview]
Message-ID: <55802A44.6040708@nod.at> (raw)
In-Reply-To: <558025B7.3030103@toshiba.co.jp>

Am 16.06.2015 um 15:33 schrieb KOBAYASHI Yoshitake:
>>> +       /* correctable */
>>> +       else if (status & NAND_STATUS_RECOM_REWRT) {
>>> +               pr_info("BENAND : Recommended to rewrite!\n");
>>> +               bitflips = chip->ecc.strength;
>>
>> In your case this might be okay, as you set strength to 1.
>> Otherweise you'd have to report the real number of bitflips.
> 
> I also thought it is okay in this case.
> BENAND return corrected data to Host NAND Controller till uncorrectable status.
> The current patch uses this Read Status command 70h to abstract BENAND Multi
> bit ECC and Need to Rewrite judgement so BENAND would look like 1bit ECC device.

The layers above MTD need to know how many bits got repaired.
It seems like BENAND suffers from the same shortcomings than On-Die-ECC. ;-\
Please see my patches how to deal with that. Maybe you can find a better solution.

Thanks,
//richard

  reply	other threads:[~2015-06-16 13:53 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-11 16:00 [PATCH v2] mtd: nand: support for Toshiba BENAND (Built-in ECC NAND) KOBAYASHI Yoshitake
2015-06-12  8:11 ` Paul Bolle
2015-06-12  8:11   ` Paul Bolle
2015-06-16 13:37   ` KOBAYASHI Yoshitake
2015-06-16 13:37     ` KOBAYASHI Yoshitake
2015-06-12  9:49 ` Richard Weinberger
2015-06-12  9:49   ` Richard Weinberger
2015-06-16 13:33   ` KOBAYASHI Yoshitake
2015-06-16 13:33     ` KOBAYASHI Yoshitake
2015-06-16 13:53     ` Richard Weinberger [this message]
2015-06-16 13:53       ` Richard Weinberger
2015-06-19 14:46       ` KOBAYASHI Yoshitake
2015-06-19 14:46         ` KOBAYASHI Yoshitake
2015-07-24 17:42 ` [PATCH REPOST v3] mtd: nand " KOBAYASHI Yoshitake

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