From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ch1outboundpool.messaging.microsoft.com (ch1ehsobe004.messaging.microsoft.com [216.32.181.184]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (Client CN "mail.global.frontbridge.com", Issuer "Microsoft Secure Server Authority" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id 6E97F1007D9 for ; Wed, 4 Jan 2012 15:36:25 +1100 (EST) Message-ID: <4F03D717.6030108@freescale.com> Date: Wed, 4 Jan 2012 10:05:35 +0530 From: Prabhakar MIME-Version: 1.0 To: Scott Wood Subject: Re: [PATCH 1/2] mtd/nand:Fix wrong address read in is_blank() References: <1325134779-3571-1-git-send-email-prabhakar@freescale.com> <1325134779-3571-2-git-send-email-prabhakar@freescale.com> <4F0363E2.6040702@freescale.com> In-Reply-To: <4F0363E2.6040702@freescale.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Cc: linux-mtd@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, Poonam Aggrwal List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wednesday 04 January 2012 01:54 AM, Scott Wood wrote: > On 12/28/2011 10:59 PM, Prabhakar Kushwaha wrote: >> IFC NAND Machine calculates ECC on 512byte sector. Same is taken care in >> fsl_ifc_run_command() while ECC status verification. Here buffer number is >> calculated assuming 512byte sector and same is passed to is_blank. >> However in is_blank() buffer address is calculated using mdt->writesize which is >> wrong. It should be calculated on basis of ecc sector size. >> >> Also, in fsl_ifc_run_command() bufferpage is calculated on the basis of ecc sector >> size instead of hard coded value. >> >> Signed-off-by: Poonam Aggrwal >> Signed-off-by: Prabhakar Kushwaha >> --- >> git://git.kernel.org/pub/scm/linux/kernel/git/galak/powerpc.git (branch next) >> >> Tested on P1010RDB >> >> drivers/mtd/nand/fsl_ifc_nand.c | 6 ++++-- >> 1 files changed, 4 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/mtd/nand/fsl_ifc_nand.c b/drivers/mtd/nand/fsl_ifc_nand.c >> index 8475b88..2df7206 100644 >> --- a/drivers/mtd/nand/fsl_ifc_nand.c >> +++ b/drivers/mtd/nand/fsl_ifc_nand.c >> @@ -191,7 +191,9 @@ static int is_blank(struct mtd_info *mtd, unsigned int bufnum) >> { >> struct nand_chip *chip = mtd->priv; >> struct fsl_ifc_mtd *priv = chip->priv; >> - u8 __iomem *addr = priv->vbase + bufnum * (mtd->writesize * 2); >> + int bufperpage = mtd->writesize / chip->ecc.size; >> + u8 __iomem *addr = priv->vbase + bufnum / bufperpage >> + * (mtd->writesize * 2); >> u32 __iomem *mainarea = (u32 *)addr; >> u8 __iomem *oob = addr + mtd->writesize; >> int i; > This function should only be checking one ECC block, not the entire > page. The caller is responsible for passing in the appropriate buffer > numbers. > > I think what the current code needs is for (mtd->writesize * 2) to be > replaced with chip->ecc.size, and for the calling code to multiply the > starting bufnum by two. Got your point :). I will take care in next patch version. >> @@ -273,7 +275,7 @@ static void fsl_ifc_run_command(struct mtd_info *mtd) >> dev_err(priv->dev, "NAND Flash Write Protect Error\n"); >> >> if (nctrl->eccread) { >> - int bufperpage = mtd->writesize / 512; >> + int bufperpage = mtd->writesize / chip->ecc.size; >> int bufnum = (nctrl->page& priv->bufnum_mask) * bufperpage; >> int bufnum_end = bufnum + bufperpage - 1; >> > Currently this driver always sets chip->ecc.size to 512. If we want to > support other ECC block sizes that future versions of IFC may have, can > we calculate bufperpage during chip init (similar to bufnum_mask) to > avoid the runtime division? It's probably not huge overhead compared to > everything else we do per NAND page transfer, but still... > Yes. I agree. We are working on this in order to support new controller version. --Prabhakar