From patchwork Wed May 13 08:17:37 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Baruch Siach X-Patchwork-Id: 471750 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2001:1868:205::9]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id F30A2140D1A for ; Wed, 13 May 2015 18:24:25 +1000 (AEST) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1YsRvE-000187-Ol; Wed, 13 May 2015 08:21:44 +0000 Received: from guitar.tcltek.co.il ([192.115.133.116] helo=mx.tkos.co.il) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1YsRsZ-0006sC-Ja; Wed, 13 May 2015 08:19:03 +0000 Received: from tarshish.tkos.co.il (unknown [10.0.8.6]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) by mx.tkos.co.il (Postfix) with ESMTPSA id 56854440809; Wed, 13 May 2015 11:18:34 +0300 (IDT) From: Baruch Siach To: David Woodhouse , Brian Norris Subject: [PATCH v3 2/4] mtd: mxc_nand: limit the size of used oob Date: Wed, 13 May 2015 11:17:37 +0300 Message-Id: <6edf6c3df2371522cb43ab864272e560176b0d5b.1431504091.git.baruch@tkos.co.il> X-Mailer: git-send-email 2.1.4 In-Reply-To: References: MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150513_011900_740292_43FEFE7C X-CRM114-Status: GOOD ( 15.57 ) X-Spam-Score: 0.0 (/) X-Spam-Report: SpamAssassin version 3.4.0 on bombadil.infradead.org summary: Content analysis details: (0.0 points) pts rule name description ---- ---------------------- -------------------------------------------------- Cc: Fabio Estevam , Baruch Siach , linux-mtd@lists.infradead.org, Sascha Hauer , =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= , Shawn Guo , linux-arm-kernel@lists.infradead.org X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-mtd" Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org For 4k pages the i.MX NFC hardware uses no more than 218 bytes for 8bit ECC data. Larger oobsize confuses the logic of copy_spare(). Limit the size of used oob size to avoid that. Reviewed-by: Sascha Hauer Acked-by: Uwe Kleine-König Signed-off-by: Baruch Siach --- v2: * Move used_oobsize into struct mxc_nand_host, and initialize it from _probe() (Uwe Kleine-König) * Add a more details to in-code comment --- drivers/mtd/nand/mxc_nand.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/drivers/mtd/nand/mxc_nand.c b/drivers/mtd/nand/mxc_nand.c index 33b22b9c0b30..51c1600d7eb9 100644 --- a/drivers/mtd/nand/mxc_nand.c +++ b/drivers/mtd/nand/mxc_nand.c @@ -189,6 +189,7 @@ struct mxc_nand_host { int clk_act; int irq; int eccsize; + int used_oobsize; int active_cs; struct completion op_completion; @@ -827,7 +828,7 @@ static void copy_spare(struct mtd_info *mtd, bool bfrom) u16 sparebuf_size = host->devtype_data->spare_len; /* size of oob chunk for all but possibly the last one */ - oob_chunk_size = (mtd->oobsize / num_chunks) & ~1; + oob_chunk_size = (host->used_oobsize / num_chunks) & ~1; if (bfrom) { for (i = 0; i < num_chunks - 1; i++) @@ -838,7 +839,7 @@ static void copy_spare(struct mtd_info *mtd, bool bfrom) /* the last chunk */ memcpy32_fromio(d + i * oob_chunk_size, s + i * sparebuf_size, - mtd->oobsize - i * oob_chunk_size); + host->used_oobsize - i * oob_chunk_size); } else { for (i = 0; i < num_chunks - 1; i++) memcpy32_toio(&s[i * sparebuf_size], @@ -848,7 +849,7 @@ static void copy_spare(struct mtd_info *mtd, bool bfrom) /* the last chunk */ memcpy32_toio(&s[oob_chunk_size * sparebuf_size], &d[i * oob_chunk_size], - mtd->oobsize - i * oob_chunk_size); + host->used_oobsize - i * oob_chunk_size); } } @@ -1606,6 +1607,15 @@ static int mxcnd_probe(struct platform_device *pdev) else if (mtd->writesize == 4096) this->ecc.layout = host->devtype_data->ecclayout_4k; + /* + * Experimentation shows that i.MX NFC can only handle up to 218 oob + * bytes. Limit used_oobsize to 218 so as to not confuse copy_spare() + * into copying invalid data to/from the spare IO buffer, as this + * might cause ECC data corruption when doing sub-page write to a + * partially written page. + */ + host->used_oobsize = min(mtd->oobsize, 218U); + if (this->ecc.mode == NAND_ECC_HW) { if (is_imx21_nfc(host) || is_imx27_nfc(host)) this->ecc.strength = 1;