On Sat,  4 Aug 2018 14:26:18 +0900
KOBAYASHI Yoshitake <yoshitake.kobaya...@toshiba.co.jp> wrote:

> This patch is a patch to support TOSHIBA MEMORY CORPORATION BENAND
> memory devices.  This use vendor specific command
> (TOSHIBA_NAND_CMD_ECC_STATUS) to know the exact bitflips.  However, I

                                            ^ exact number of bitflips

> could not test this patch because I do not have a platform that
> supports chip-> exec_op.  Therefore, I post this patch as RFC.

           ^ chip->exec_op()

How about adding ->exec_op() support to the controller driver you're
testing with?

> As soon as I get a platform that supports chip-> exec_op, I would like
> to test and re-post.

All the explanation about why this is an RFC should be placed after the
'---' separator so that it does not appear when we apply the patch.

> 
> Signed-off-by: KOBAYASHI Yoshitake <yoshitake.kobaya...@toshiba.co.jp>

With the commit message adjusted as suggested above,

Reviewed-by: Boris Brezillon <boris.brezil...@bootlin.com>


> ---
>  drivers/mtd/nand/raw/nand_toshiba.c | 53 
> ++++++++++++++++++++++++++++++++++++-
>  1 file changed, 52 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/nand/raw/nand_toshiba.c 
> b/drivers/mtd/nand/raw/nand_toshiba.c
> index 8aec3fa..3f4683b 100644
> --- a/drivers/mtd/nand/raw/nand_toshiba.c
> +++ b/drivers/mtd/nand/raw/nand_toshiba.c
> @@ -23,14 +23,65 @@
>  /* Recommended to rewrite for BENAND */
>  #define TOSHIBA_NAND_STATUS_REWRITE_RECOMMENDED      BIT(3)
>  
> +/* ECC Status Read Command for BENAND */
> +#define TOSHIBA_NAND_CMD_ECC_STATUS_READ     0x7A
> +
> +/* ECC Status Mask for BENAND */
> +#define TOSHIBA_NAND_ECC_STATUS_MASK         0x0F
> +
> +/* Uncorrectable Error for BENAND */
> +#define TOSHIBA_NAND_ECC_STATUS_UNCORR               0x0F
> +
> +static int toshiba_nand_benand_read_eccstatus_op(struct nand_chip *chip,
> +                                              u8 *buf)
> +{
> +     u8 *ecc_status = buf;
> +
> +     if (chip->exec_op) {
> +             const struct nand_sdr_timings *sdr =
> +                     nand_get_sdr_timings(&chip->data_interface);
> +             struct nand_op_instr instrs[] = {
> +                     NAND_OP_CMD(TOSHIBA_NAND_CMD_ECC_STATUS_READ,
> +                                 PSEC_TO_NSEC(sdr->tADL_min)),
> +                     NAND_OP_8BIT_DATA_IN(chip->ecc.steps, ecc_status, 0),
> +             };
> +             struct nand_operation op = NAND_OPERATION(instrs);
> +
> +             return nand_exec_op(chip, &op);
> +     }
> +
> +     return -ENOTSUPP;
> +}
> +
>  static int toshiba_nand_benand_eccstatus(struct mtd_info *mtd,
>                                        struct nand_chip *chip)
>  {
>       int ret;
>       unsigned int max_bitflips = 0;
> -     u8 status;
> +     u8 status, ecc_status[8];
>  
>       /* Check Status */
> +     ret = toshiba_nand_benand_read_eccstatus_op(chip, ecc_status);
> +     if (!ret) {
> +             unsigned int i, bitflips = 0;
> +
> +             for (i = 0; i < chip->ecc.steps; i++) {
> +                     bitflips = ecc_status[i] & TOSHIBA_NAND_ECC_STATUS_MASK;
> +                     if (bitflips == TOSHIBA_NAND_ECC_STATUS_UNCORR) {
> +                             mtd->ecc_stats.failed++;
> +                     } else {
> +                             mtd->ecc_stats.corrected += bitflips;
> +                             max_bitflips = max(max_bitflips, bitflips);
> +                     }
> +             }
> +
> +             return max_bitflips;
> +     }
> +
> +     /*
> +      * Fallback to regular status check if
> +      * toshiba_nand_benand_read_eccstatus_op() failed.
> +      */
>       ret = nand_status_op(chip, &status);
>       if (ret)
>               return ret;

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