Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966022AbcJFIwV (ORCPT ); Thu, 6 Oct 2016 04:52:21 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:48736 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965502AbcJFIwT (ORCPT ); Thu, 6 Oct 2016 04:52:19 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Karl Beldan , Boris Brezillon , Brian Norris Subject: [PATCH 4.4 02/93] mtd: nand: davinci: Reinitialize the HW ECC engine in 4bit hwctl Date: Thu, 6 Oct 2016 10:28:32 +0200 Message-Id: <20161006074731.254965277@linuxfoundation.org> X-Mailer: git-send-email 2.10.0 In-Reply-To: <20161006074731.150212126@linuxfoundation.org> References: <20161006074731.150212126@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1921 Lines: 53 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Karl Beldan commit f6d7c1b5598b6407c3f1da795dd54acf99c1990c upstream. This fixes subpage writes when using 4-bit HW ECC. There has been numerous reports about ECC errors with devices using this driver for a while. Also the 4-bit ECC has been reported as broken with subpages in [1] and with 16 bits NANDs in the driver and in mach* board files both in mainline and in the vendor BSPs. What I saw with 4-bit ECC on a 16bits NAND (on an LCDK) which got me to try reinitializing the ECC engine: - R/W on whole pages properly generates/checks RS code - try writing the 1st subpage only of a blank page, the subpage is well written and the RS code properly generated, re-reading the same page the HW detects some ECC error, reading the same page again no ECC error is detected Note that the ECC engine is already reinitialized in the 1-bit case. Tested on my LCDK with UBI+UBIFS using subpages. This could potentially get rid of the issue workarounded in [1]. [1] 28c015a9daab ("mtd: davinci-nand: disable subpage write for keystone-nand") Fixes: 6a4123e581b3 ("mtd: nand: davinci_nand, 4-bit ECC for smallpage") Signed-off-by: Karl Beldan Acked-by: Boris Brezillon Signed-off-by: Brian Norris Signed-off-by: Greg Kroah-Hartman --- drivers/mtd/nand/davinci_nand.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/mtd/nand/davinci_nand.c +++ b/drivers/mtd/nand/davinci_nand.c @@ -241,6 +241,9 @@ static void nand_davinci_hwctl_4bit(stru unsigned long flags; u32 val; + /* Reset ECC hardware */ + davinci_nand_readl(info, NAND_4BIT_ECC1_OFFSET); + spin_lock_irqsave(&davinci_nand_lock, flags); /* Start 4-bit ECC calculation for read/write */