From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:43878 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751308AbcJDHqs (ORCPT ); Tue, 4 Oct 2016 03:46:48 -0400 Subject: Patch "mtd: nand: davinci: Reinitialize the HW ECC engine in 4bit hwctl" has been added to the 4.4-stable tree To: kbeldan@baylibre.com, boris.brezillon@free-electrons.com, computersforpeace@gmail.com, gregkh@linuxfoundation.org Cc: , From: Date: Tue, 04 Oct 2016 09:07:35 +0200 Message-ID: <147556485510924@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled mtd: nand: davinci: Reinitialize the HW ECC engine in 4bit hwctl to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mtd-nand-davinci-reinitialize-the-hw-ecc-engine-in-4bit-hwctl.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From f6d7c1b5598b6407c3f1da795dd54acf99c1990c Mon Sep 17 00:00:00 2001 From: Karl Beldan Date: Mon, 29 Aug 2016 07:45:49 +0000 Subject: mtd: nand: davinci: Reinitialize the HW ECC engine in 4bit hwctl 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 */ Patches currently in stable-queue which might be from kbeldan@baylibre.com are queue-4.4/mtd-nand-davinci-reinitialize-the-hw-ecc-engine-in-4bit-hwctl.patch