From patchwork Wed Mar 14 06:17:12 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vipin Kumar X-Patchwork-Id: 146548 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:4978:20e::2]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id C7F88B6EF4 for ; Wed, 14 Mar 2012 17:19:57 +1100 (EST) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1S7hXw-0002yj-Ts; Wed, 14 Mar 2012 06:18:52 +0000 Received: from eu1sys200aog117.obsmtp.com ([207.126.144.143]) by merlin.infradead.org with smtps (Exim 4.76 #1 (Red Hat Linux)) id 1S7hXV-0002mS-Gs for linux-mtd@lists.infradead.org; Wed, 14 Mar 2012 06:18:26 +0000 Received: from beta.dmz-ap.st.com ([138.198.100.35]) (using TLSv1) by eu1sys200aob117.postini.com ([207.126.147.11]) with SMTP ID DSNKT2A4LPDWKa1w07YWwsDVQb503UZr9m+7@postini.com; Wed, 14 Mar 2012 06:18:25 UTC Received: from zeta.dmz-ap.st.com (ns6.st.com [138.198.234.13]) by beta.dmz-ap.st.com (STMicroelectronics) with ESMTP id C2DD4C4; Wed, 14 Mar 2012 06:09:54 +0000 (GMT) Received: from Webmail-ap.st.com (eapex1hubcas1.st.com [10.80.176.8]) by zeta.dmz-ap.st.com (STMicroelectronics) with ESMTP id 444E51755; Wed, 14 Mar 2012 06:18:18 +0000 (GMT) Received: from localhost (10.199.82.151) by Webmail-ap.st.com (10.80.176.7) with Microsoft SMTP Server (TLS) id 8.3.192.1; Wed, 14 Mar 2012 14:17:39 +0800 From: Vipin Kumar To: , Subject: [PATCH v2 06/13] nand/fsmc: Initialize the badblockbits to 7 Date: Wed, 14 Mar 2012 11:47:12 +0530 Message-ID: <900367e4195091bb17bbba2f996680b9d0bece16.1331705527.git.vipin.kumar@st.com> X-Mailer: git-send-email 1.7.0.4 In-Reply-To: References: MIME-Version: 1.0 X-Spam-Note: CRM114 invocation failed X-Spam-Score: -4.2 (----) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-4.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [207.126.144.143 listed in list.dnswl.org] -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: sr@denx.de, Vipin Kumar , linus.walleij@linaro.org, spear-devel@list.st.com X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-mtd-bounces@lists.infradead.org Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org Ideally, the block should have 0xff written on the bad block position. Any value other than 0xff implies a bad block. In practical situations, there can be bit flips in the oob area as well which means that a block with 0x7f being read at bad block position may imply a bad block but it is infact only a bit flip in the bad block byte. To resolve this problem, the block is marked as good if number of high bits is greater than or equal to badblockbits (initialized to 7) Signed-off-by: Vipin Kumar --- drivers/mtd/nand/fsmc_nand.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/drivers/mtd/nand/fsmc_nand.c b/drivers/mtd/nand/fsmc_nand.c index 745db62..bfc924f 100644 --- a/drivers/mtd/nand/fsmc_nand.c +++ b/drivers/mtd/nand/fsmc_nand.c @@ -802,6 +802,7 @@ static int __init fsmc_nand_probe(struct platform_device *pdev) nand->ecc.size = 512; nand->options = pdata->options; nand->select_chip = fsmc_select_chip; + nand->badblockbits = 7; if (pdata->width == FSMC_NAND_BW16) nand->options |= NAND_BUSWIDTH_16;