From patchwork Tue Nov 3 10:31:10 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rajashekhara, Sudhakar" X-Patchwork-Id: 57266 Received: from devils.ext.ti.com (devils.ext.ti.com [198.47.26.153]) by demeter.kernel.org (8.14.2/8.14.2) with ESMTP id nA3AgLTF015732 for ; Tue, 3 Nov 2009 10:42:23 GMT Received: from dlep35.itg.ti.com ([157.170.170.118]) by devils.ext.ti.com (8.13.7/8.13.7) with ESMTP id nA3AelZA012765 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Tue, 3 Nov 2009 04:40:48 -0600 Received: from linux.omap.com (localhost [127.0.0.1]) by dlep35.itg.ti.com (8.13.7/8.13.7) with ESMTP id nA3Ael0L025015; Tue, 3 Nov 2009 04:40:47 -0600 (CST) Received: from linux.omap.com (localhost [127.0.0.1]) by linux.omap.com (Postfix) with ESMTP id 7169F80627; Tue, 3 Nov 2009 04:40:47 -0600 (CST) X-Original-To: davinci-linux-open-source@linux.davincidsp.com Delivered-To: davinci-linux-open-source@linux.davincidsp.com Received: from dflp53.itg.ti.com (dflp53.itg.ti.com [128.247.5.6]) by linux.omap.com (Postfix) with ESMTP id 163B180626 for ; Tue, 3 Nov 2009 04:40:47 -0600 (CST) Received: from tidmzi-ftp.india.ext.ti.com (localhost [127.0.0.1]) by dflp53.itg.ti.com (8.13.8/8.13.8) with SMTP id nA3AeiSL027067; Tue, 3 Nov 2009 04:40:45 -0600 (CST) Received: from symphonyindia.ti.com (symphony-ftp [192.168.247.11]) by tidmzi-ftp.india.ext.ti.com (Postfix) with SMTP id E74753886B; Tue, 3 Nov 2009 16:07:36 +0530 (IST) Received: from localhost.localdomain ([192.168.247.76]) by symphonyindia.ti.com (8.13.1/8.12.10) with ESMTP id nA3AUVDU015535; Tue, 3 Nov 2009 16:00:31 +0530 From: Sudhakar Rajashekhara To: linux-mtd@lists.infradead.org Date: Tue, 3 Nov 2009 16:01:10 +0530 Message-Id: <1257244270-2433-1-git-send-email-sudhakar.raj@ti.com> X-Mailer: git-send-email 1.5.6 Cc: akpm@linux-foundation.org, davinci-linux-open-source@linux.davincidsp.com Subject: [PATCH] mtd-nand: davinci: Correct 4-bit error correction X-BeenThere: davinci-linux-open-source@linux.davincidsp.com X-Mailman-Version: 2.1.4 Precedence: list List-Id: davinci-linux-open-source.linux.davincidsp.com List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: davinci-linux-open-source-bounces@linux.davincidsp.com Errors-To: davinci-linux-open-source-bounces@linux.davincidsp.com diff --git a/drivers/mtd/nand/davinci_nand.c b/drivers/mtd/nand/davinci_nand.c index fe3eba8..8a32999 100644 --- a/drivers/mtd/nand/davinci_nand.c +++ b/drivers/mtd/nand/davinci_nand.c @@ -310,6 +310,7 @@ static int nand_davinci_correct_4bit(struct mtd_info *mtd, unsigned short ecc10[8]; unsigned short *ecc16; u32 syndrome[4]; + u32 ecc_state; unsigned num_errors, corrected; /* All bytes 0xff? It's an erased page; ignore its ECC. */ @@ -360,6 +361,21 @@ compare: */ davinci_nand_writel(info, NANDFCR_OFFSET, davinci_nand_readl(info, NANDFCR_OFFSET) | BIT(13)); + + /* + * ECC_STATE field reads 0x3 (Error correction complete) immediately + * after setting the 4BITECC_ADD_CALC_START bit. So if you immediately + * begin trying to poll for the state, you may fall right out of your + * loop without any of the correction calculations having taken place. + * The recommendation from the hardware team is to wait till ECC_STATE + * reads less than 4, which means ECC HW has entered correction state. + */ + do { + ecc_state = (davinci_nand_readl(info, + NANDFSR_OFFSET) >> 8) & 0x0f; + cpu_relax(); + } while (ecc_state < 4); + for (;;) { u32 fsr = davinci_nand_readl(info, NANDFSR_OFFSET);