From patchwork Mon May 9 14:21:39 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: kishore kadiyala X-Patchwork-Id: 769212 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter2.kernel.org (8.14.4/8.14.3) with ESMTP id p49ED8lG005707 for ; Mon, 9 May 2011 14:13:08 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753362Ab1EIOM5 (ORCPT ); Mon, 9 May 2011 10:12:57 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:47026 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753338Ab1EIOM4 (ORCPT ); Mon, 9 May 2011 10:12:56 -0400 Received: from dbdp20.itg.ti.com ([172.24.170.38]) by devils.ext.ti.com (8.13.7/8.13.7) with ESMTP id p49ECoMf030650 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Mon, 9 May 2011 09:12:52 -0500 Received: from dbde71.ent.ti.com (localhost [127.0.0.1]) by dbdp20.itg.ti.com (8.13.8/8.13.8) with ESMTP id p49ECna7004444; Mon, 9 May 2011 19:42:49 +0530 (IST) Received: from dbdp31.itg.ti.com (172.24.170.98) by DBDE71.ent.ti.com (172.24.170.149) with Microsoft SMTP Server id 8.3.106.1; Mon, 9 May 2011 19:42:49 +0530 Received: from ucmsshproxy.india.ext.ti.com (dbdp20.itg.ti.com [172.24.170.38]) by dbdp31.itg.ti.com (8.13.8/8.13.8) with SMTP id p49EClTk004248; Mon, 9 May 2011 19:42:47 +0530 (IST) Received: from localhost (unknown [10.24.244.72]) by ucmsshproxy.india.ext.ti.com (Postfix) with ESMTP id 6E275158002; Mon, 9 May 2011 19:42:47 +0530 (IST) From: Kishore Kadiyala To: , , CC: Kishore Kadiyala , Vimal Singh Subject: [PATCH RESEND] omap : nand : fix subpage ecc issue with prefetch Date: Mon, 9 May 2011 19:51:39 +0530 Message-ID: <1304950899-26009-1-git-send-email-kishore.kadiyala@ti.com> X-Mailer: git-send-email 1.7.4.1 MIME-Version: 1.0 Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter2.kernel.org [140.211.167.43]); Mon, 09 May 2011 14:13:08 +0000 (UTC) When reading/writing a subpage (When HW ECC is not available/enabled) for number of bytes not aligned to 4, the mis-aligned bytes are handled first (by cpu copy method) before enabling the Prefetch engine to/from 'p'(start of buffer 'buf'). Then it reads/writes rest of the bytes with the help of Prefetch engine, if available, or again using cpu copy method. Currently, reading/writing of rest of bytes, is not done correctly since its trying to read/write again to/from begining of buffer 'buf', overwriting the mis-aligned bytes. Read & write using prefetch engine got broken in commit '2c01946c'. We never hit a scenario of not getting 'gpmc_prefetch_enable' call success. So, problem did not get caught up. Signed-off-by: Kishore Kadiyala Signed-off-by: Vimal Singh Reported-by: Bryan DE FARIA --- drivers/mtd/nand/omap2.c | 12 +++++------- 1 files changed, 5 insertions(+), 7 deletions(-) diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c index da9a351..2c8040f 100644 --- a/drivers/mtd/nand/omap2.c +++ b/drivers/mtd/nand/omap2.c @@ -263,11 +263,10 @@ static void omap_read_buf_pref(struct mtd_info *mtd, u_char *buf, int len) if (ret) { /* PFPW engine is busy, use cpu copy method */ if (info->nand.options & NAND_BUSWIDTH_16) - omap_read_buf16(mtd, buf, len); + omap_read_buf16(mtd, (u_char *)p, len); else - omap_read_buf8(mtd, buf, len); + omap_read_buf8(mtd, (u_char *)p, len); } else { - p = (u32 *) buf; do { r_count = gpmc_read_status(GPMC_PREFETCH_FIFO_CNT); r_count = r_count >> 2; @@ -293,7 +292,7 @@ static void omap_write_buf_pref(struct mtd_info *mtd, struct omap_nand_info, mtd); uint32_t w_count = 0; int i = 0, ret = 0; - u16 *p; + u16 *p = (u16 *)buf; unsigned long tim, limit; /* take care of subpage writes */ @@ -309,11 +308,10 @@ static void omap_write_buf_pref(struct mtd_info *mtd, if (ret) { /* PFPW engine is busy, use cpu copy method */ if (info->nand.options & NAND_BUSWIDTH_16) - omap_write_buf16(mtd, buf, len); + omap_write_buf16(mtd, (u_char *)p, len); else - omap_write_buf8(mtd, buf, len); + omap_write_buf8(mtd, (u_char *)p, len); } else { - p = (u16 *) buf; while (len) { w_count = gpmc_read_status(GPMC_PREFETCH_FIFO_CNT); w_count = w_count >> 1;