From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1040178AbdDUNtV (ORCPT ); Fri, 21 Apr 2017 09:49:21 -0400 Received: from mail.free-electrons.com ([62.4.15.54]:43992 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1040084AbdDUNtU (ORCPT ); Fri, 21 Apr 2017 09:49:20 -0400 Date: Fri, 21 Apr 2017 15:49:03 +0200 From: Boris Brezillon To: Pavel Machek Cc: Dipen.Dudhat@freescale.com, richard@nod.at, dwmw2@infradead.org, computersforpeace@gmail.com, marek.vasut@gmail.com, cyrille.pitchen@atmel.com, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, mark.marshall@omicronenergy.com, b44839@freescale.com, prabhakar@freescale.com Subject: Re: fsl_ifc_nand: are blank pages protected by ECC? Message-ID: <20170421154903.2782cd06@bbrezillon> In-Reply-To: <20170421133721.GA15332@amd> References: <20170419121332.GA26979@amd> <20170419231804.5a04ed69@bbrezillon> <20170421100813.GA4332@amd> <20170421133721.GA15332@amd> X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 21 Apr 2017 15:37:21 +0200 Pavel Machek wrote: > Hi! > > > (Added driver author to the cc list, maybe he can help). > > > > > UBIFS complains: > > > > > > > > UBIFS error (pid 931): ubifs_scan: corrupt empty space at LEB 282:252630 > > > > UBIFS error (pid 931): ubifs_scanned_corruption: corruption at LEB 282:252630 > > > > UBIFS error (pid 931): ubifs_scanned_corruption: first 1322 bytes from LEB 282:252630 > > > > UBIFS error (pid 931): ubifs_scan: LEB 282 scanning failed > ... > > > > is_blank() checks for all 0xff's, so single-bit 0xfe in the data will > > > > result in_blank() == 0 and uncorrectable error being signaled. > > > > > > > > Should the driver be modified somehow? > > > > > > Yep, nand_check_erased_ecc_chunk() [1] is here to help you check this > > > case, unfortunately, it's not directly applicable here, because this > > Maybe I figured it out. Unfortunately, it is only compile tested. Does > it look approximately right? Yep that's definitely better. Just one thing missing (see below), otherwise it looks good. > > Thanks, > Pavel > > --- a/drivers/mtd/nand/fsl_ifc_nand.c > +++ b/drivers/mtd/nand/fsl_ifc_nand.c > @@ -171,32 +171,6 @@ static void set_addr(struct mtd_info *mtd, int column, int page_addr, int oob) > ifc_nand_ctrl->index += mtd->writesize; > } > > -static int is_blank(struct mtd_info *mtd, unsigned int bufnum) > -{ > - struct nand_chip *chip = mtd_to_nand(mtd); > - struct fsl_ifc_mtd *priv = nand_get_controller_data(chip); > - u8 __iomem *addr = priv->vbase + bufnum * (mtd->writesize * 2); > - u32 __iomem *mainarea = (u32 __iomem *)addr; > - u8 __iomem *oob = addr + mtd->writesize; > - struct mtd_oob_region oobregion = { }; > - int i, section = 0; > - > - i = nand_check_erased_buf(&mainarea[i], mtd->writesize, 0); > - if (i) > - return 0; > - > - mtd_ooblayout_ecc(mtd, section++, &oobregion); > - while (oobregion.length) { > - i = nand_check_erased_buf(&oob[oobregion.offset], oobregion.length, 0); > - if (i) > - return 0; > - > - mtd_ooblayout_ecc(mtd, section++, &oobregion); > - } > - > - return 1; > -} > - > /* returns nonzero if entire page is blank */ > static int check_read_ecc(struct mtd_info *mtd, struct fsl_ifc_ctrl *ctrl, > u32 *eccstat, unsigned int bufnum) > @@ -272,16 +246,14 @@ static void fsl_ifc_run_command(struct mtd_info *mtd) > if (errors == 15) { > /* > * Uncorrectable error. > - * OK only if the whole page is blank. > + * We'll check for blank pages later. > * > * We disable ECCER reporting due to... > * erratum IFC-A002770 -- so report it now if we > * see an uncorrectable error in ECCSTAT. > */ > - if (!is_blank(mtd, bufnum)) > - ctrl->nand_stat |= > - IFC_NAND_EVTER_STAT_ECCER; > - break; > + ctrl->nand_stat |= IFC_NAND_EVTER_STAT_ECCER; > + printk("NAND flash read: error but continuing.\n"); > } > > mtd->ecc_stats.corrected += errors; > @@ -676,6 +648,40 @@ static int fsl_ifc_wait(struct mtd_info *mtd, struct nand_chip *chip) > return nand_fsr | NAND_STATUS_WP; > } > > +/* > + * The controller does not check for bitflips in erased pages, > + * therefore software must check instead. > + */ > +static int check_erased_page(struct nand_chip *chip, u8 *buf) > +{ > + struct mtd_info *mtd = nand_to_mtd(chip); > + u8 *ecc = chip->oob_poi; > + const int ecc_size = chip->ecc.bytes; > + const int pkt_size = chip->ecc.size; > + int i, res, bitflips = 0; > + struct mtd_oob_region oobregion = { }; > + > + mtd_ooblayout_ecc(mtd, 0, &oobregion); > + ecc += oobregion.offset; > + > + for (i = 0; i < chip->ecc.steps; ++i) { > + res = nand_check_erased_ecc_chunk(buf, pkt_size, ecc, ecc_size, > + NULL, 0, > + chip->ecc.strength); > + if (res < 0) > + mtd->ecc_stats.failed++; else mtd->ecc_stats.corrected += res; > + > + bitflips = max(res, bitflips); > + buf += pkt_size; > + ecc += ecc_size; > + } > + > + mtd_ooblayout_ecc(mtd, 1, &oobregion); > + BUG_ON(oobregion.length); Probably something you should check at registration time only. > + > + return bitflips; > +} > + > static int fsl_ifc_read_page(struct mtd_info *mtd, struct nand_chip *chip, > uint8_t *buf, int oob_required, int page) > { > @@ -687,11 +693,23 @@ static int fsl_ifc_read_page(struct mtd_info *mtd, struct nand_chip *chip, > if (oob_required) > fsl_ifc_read_buf(mtd, chip->oob_poi, mtd->oobsize); > > - if (ctrl->nand_stat & IFC_NAND_EVTER_STAT_ECCER) > - dev_err(priv->dev, "NAND Flash ECC Uncorrectable Error\n"); > - > if (ctrl->nand_stat != IFC_NAND_EVTER_STAT_OPC) > mtd->ecc_stats.failed++; > + > + if (ctrl->nand_stat & IFC_NAND_EVTER_STAT_ECCER) { > + int res; > + > + if (!oob_required) > + fsl_ifc_read_buf(mtd, chip->oob_poi, mtd->oobsize); > + > + printk("NAND flash: have error (%d)\n", nctrl->max_bitflips); > + res = check_erased_page(chip, buf); > + printk("NAND flash: but erased page says %d\n", res); > + > + dev_err(priv->dev, "NAND Flash ECC Uncorrectable Error or erased page\n"); > + return res; > + } > + > > return nctrl->max_bitflips; > } >