From: Sascha Hauer <s.hauer@pengutronix.de>
To: Christian Hemp <c.hemp@phytec.de>
Cc: barebox@lists.infradead.org, Stefan Lengfeld <s.lengfeld@phytec.de>
Subject: Re: [PATCH 2/2] mtd: nand: nand_mxs: Fix readtotal calculation
Date: Fri, 21 Oct 2016 09:18:08 +0200 [thread overview]
Message-ID: <20161021071808.ygaw53zjn3x5ns6f@pengutronix.de> (raw)
In-Reply-To: <1476970807-43811-2-git-send-email-c.hemp@phytec.de>
On Thu, Oct 20, 2016 at 03:40:07PM +0200, Christian Hemp wrote:
> The calculation of readtotal must be bit alligend. If not the bch core
> finds bit flips in every page, because readtotal is too small.
> This bug was mostly introduced since commit "51061a9 mtd: nand: nand_mxs:
> Add subpage read support".
Is this somehow related to:
http://lists.infradead.org/pipermail/linux-mtd/2016-June/068243.html
Or is this another topic?
Sascha
>
> Tested with:
> nand: NAND device: Manufacturer ID: 0x01, Chip ID: 0xd3 (AMD/Spansion
> S34ML08G2), 1024MiB, page size: 2048, OOB size: 128
>
> nand: NAND device: Manufacturer ID: 0x2c, Chip ID: 0xdc (Micron
> MT29F4G08ABADAWP), 512MiB, page size: 2048, OOB size: 64
>
> nand: NAND device: Manufacturer ID: 0xec, Chip ID: 0xd3 (Samsung NAND
> 1GiB 3,3V 8-bit), 1024MiB, page size: 2048, OOB size: 64
>
> Signed-off-by: Christian Hemp <c.hemp@phytec.de>
> Signed-off-by: Stefan Lengfeld <s.lengfeld@phytec.de>
> ---
> drivers/mtd/nand/nand_mxs.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mtd/nand/nand_mxs.c b/drivers/mtd/nand/nand_mxs.c
> index fe955e8..cba0bee 100644
> --- a/drivers/mtd/nand/nand_mxs.c
> +++ b/drivers/mtd/nand/nand_mxs.c
> @@ -728,15 +728,15 @@ static int __mxs_nand_ecc_read_page(struct mtd_info *mtd, struct nand_chip *nand
> uint32_t corrected = 0, failed = 0;
> uint8_t *status;
> unsigned int max_bitflips = 0;
> - int i, ret, readtotal, nchunks, eccstrength, ecc_parity_size;
> + int i, ret, readtotal, nchunks, eccstrength;
>
> eccstrength = mxs_nand_get_ecc_strength(mtd->writesize, mtd->oobsize);
>
> readlen = roundup(readlen, MXS_NAND_CHUNK_DATA_CHUNK_SIZE);
> nchunks = mxs_nand_ecc_chunk_cnt(readlen);
> - ecc_parity_size = 13 * eccstrength / 8;
> - readtotal = MXS_NAND_METADATA_SIZE +
> - (MXS_NAND_CHUNK_DATA_CHUNK_SIZE + ecc_parity_size) * nchunks;
> + readtotal = MXS_NAND_METADATA_SIZE;
> + readtotal += MXS_NAND_CHUNK_DATA_CHUNK_SIZE * nchunks;
> + readtotal += DIV_ROUND_UP(13 * eccstrength * nchunks, 8);
>
> mxs_nand_config_bch(mtd, readtotal);
>
> --
> 1.9.1
>
>
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>
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next prev parent reply other threads:[~2016-10-21 7:18 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-20 13:40 [PATCH 1/2] nand: imx6: Changed default NAND clock Christian Hemp
2016-10-20 13:40 ` [PATCH 2/2] mtd: nand: nand_mxs: Fix readtotal calculation Christian Hemp
2016-10-21 7:18 ` Sascha Hauer [this message]
2016-10-24 8:51 ` Stefan Lengfeld
2016-10-21 7:11 ` [PATCH 1/2] nand: imx6: Changed default NAND clock Sascha Hauer
2016-10-24 9:20 ` Stefan Lengfeld
2016-10-25 6:21 ` Sascha Hauer
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