From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756502AbbFPNxT (ORCPT ); Tue, 16 Jun 2015 09:53:19 -0400 Received: from a.ns.miles-group.at ([95.130.255.143]:65275 "EHLO radon.swed.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754604AbbFPNxM (ORCPT ); Tue, 16 Jun 2015 09:53:12 -0400 Message-ID: <55802A44.6040708@nod.at> Date: Tue, 16 Jun 2015 15:53:08 +0200 From: Richard Weinberger User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: KOBAYASHI Yoshitake CC: David Woodhouse , Brian Norris , "linux-mtd@lists.infradead.org" , LKML Subject: Re: [PATCH v2] mtd: nand: support for Toshiba BENAND (Built-in ECC NAND) References: <1434038402-26365-1-git-send-email-yoshitake.kobayashi@toshiba.co.jp> <558025B7.3030103@toshiba.co.jp> In-Reply-To: <558025B7.3030103@toshiba.co.jp> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from a.ns.miles-group.at ([95.130.255.143] helo=radon.swed.at) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Z4rPX-00011y-6f for linux-mtd@lists.infradead.org; Tue, 16 Jun 2015 14:00:20 +0000 Message-ID: <55802A44.6040708@nod.at> Date: Tue, 16 Jun 2015 15:53:08 +0200 From: Richard Weinberger MIME-Version: 1.0 To: KOBAYASHI Yoshitake Subject: Re: [PATCH v2] mtd: nand: support for Toshiba BENAND (Built-in ECC NAND) References: <1434038402-26365-1-git-send-email-yoshitake.kobayashi@toshiba.co.jp> <558025B7.3030103@toshiba.co.jp> In-Reply-To: <558025B7.3030103@toshiba.co.jp> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: "linux-mtd@lists.infradead.org" , Brian Norris , David Woodhouse , LKML List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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