From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3D848C4338F for ; Mon, 23 Aug 2021 15:04:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1D2BD61245 for ; Mon, 23 Aug 2021 15:04:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230437AbhHWPEm convert rfc822-to-8bit (ORCPT ); Mon, 23 Aug 2021 11:04:42 -0400 Received: from relay8-d.mail.gandi.net ([217.70.183.201]:47821 "EHLO relay8-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230364AbhHWPEl (ORCPT ); Mon, 23 Aug 2021 11:04:41 -0400 Received: (Authenticated sender: miquel.raynal@bootlin.com) by relay8-d.mail.gandi.net (Postfix) with ESMTPSA id 2D1E01BF203; Mon, 23 Aug 2021 15:03:55 +0000 (UTC) Date: Mon, 23 Aug 2021 17:03:54 +0200 From: Miquel Raynal To: Daniel Palmer Cc: linux-mtd@lists.infradead.org, richard@nod.at, Linux Kernel Mailing List , linux-arm-kernel Subject: Re: [PATCH v3] mtd: spinand: add support for Foresee FS35ND0*G parts Message-ID: <20210823170354.2dccabd5@xps13> In-Reply-To: References: <20210811084924.52293-1-daniel@0x0f.com> <20210816101143.2a64d7b9@xps13> <20210823162148.35a24183@xps13> Organization: Bootlin X-Mailer: Claws Mail 3.17.7 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Daniel, Daniel Palmer wrote on Mon, 23 Aug 2021 23:54:20 +0900: > Hi Miquel, > > On Mon, 23 Aug 2021 at 23:21, Miquel Raynal wrote: > > I am not sure to follow, above the software says "3 corrected bf" while > > Due to the status being "between 0 and 3 bitflips" I think it'll > basically report 3 most of the time. > As a refresher we seem to have a status for 0 - 3 flips but ok, 4 bit > flips but ok, and >4 flips no go. > In most cases (0 - 3) the driver is reporting 3. > > > I thought the problem was when getting 4 bf, but the dump show many > > more. Can you show me how it behaves: > > * erase (like you did) > > * insert {1, 2, 3, 4, 5} bf and show the dump each time? > > Here's a complete log of erasing the page then flipping all the bits > in the first byte. > > # flash_erase /dev/mtd0 0x8000000 1 > Erasing 128 Kibyte @ 8000000 -- 100 % complete > # nanddump --bb=dumpbad -s 0x8000000 -l 1 -c -p /dev/mtd0 | head -n 10 > ECC failed: 0 > ECC corrected: 6249 > Number of bad blocks: 0 > Number of bbt blocks: 0 > Block size 131072, page size 2048, OOB size 64 > Dumping data starting at 0x08000000 and ending at 0x08000001... > ECC: 3 corrected bitflip(s) at offset 0x08000000 > 0x08000000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000010: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000020: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000030: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000040: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000050: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000060: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000070: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000090: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > # nandflipbits /dev/mtd0 0@0x8000000 > # nanddump --bb=dumpbad -s 0x8000000 -l 1 -c -p /dev/mtd0 | head -n 10 > ECC failed: 0 > ECC corrected: 6252 > Number of bad blocks: 0 > Number of bbt blocks: 0 > Block size 131072, page size 2048, OOB size 64 > Dumping data starting at 0x08000000 and ending at 0x08000001... > ECC: 3 corrected bitflip(s) at offset 0x08000000 > 0x08000000: fe ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| How is this result possible? You are dumping with the ECC engine enabled, it reports 3 bf (meaning that it is actually running, at least the software really thinks there is an on-die engine enabled) but the data has not been corrected. I expect the first byte to be 0xFF after correction. Only with -n (raw dump) we should see this. > 0x08000010: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000020: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000030: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000040: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000050: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000060: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000070: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000090: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| Thanks, Miquèl