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 <poonam.aggr...@freescale.com>
> Signed-off-by: Prabhakar Kushwaha <prabha...@freescale.com>
> ---
> 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.
> @@ -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...
-Scott
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