[PATCH v8 6/7] mtd: nand: gpmi: correct bitflip for erased NAND page

Huang Shijie shijie.huang at arm.com
Wed Dec 16 18:11:22 PST 2015


On Wed, Dec 02, 2015 at 04:47:45PM -0600, Han Xu wrote:
> i.MX6QP and i.MX7D BCH module integrated a new feature to detect the
> bitflip number for erased NAND page. So for these two platform, set the
> erase threshold to ecc_strength and if bitflip detected, GPMI driver will
> correct the data to all 0xFF.
>
> Signed-off-by: Han Xu <b45815 at freescale.com>
> ---
>  drivers/mtd/nand/gpmi-nand/bch-regs.h  | 10 ++++++++++
>  drivers/mtd/nand/gpmi-nand/gpmi-lib.c  |  5 +++++
>  drivers/mtd/nand/gpmi-nand/gpmi-nand.c | 24 +++++++++++++++++++++++-
>  drivers/mtd/nand/gpmi-nand/gpmi-nand.h |  5 ++++-
>  4 files changed, 42 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mtd/nand/gpmi-nand/bch-regs.h b/drivers/mtd/nand/gpmi-nand/bch-regs.h
> index 53e58bc..a84d72b 100644
> --- a/drivers/mtd/nand/gpmi-nand/bch-regs.h
> +++ b/drivers/mtd/nand/gpmi-nand/bch-regs.h
> @@ -30,7 +30,13 @@
>  #define BM_BCH_CTRL_COMPLETE_IRQ             (1 << 0)
>
>  #define HW_BCH_STATUS0                               0x00000010
> +
>  #define HW_BCH_MODE                          0x00000020
> +#define BP_BCH_MODE_ERASE_THRESHOLD          0
> +#define BM_BCH_MODE_ERASE_THRESHOLD  (0xff << BP_BCH_MODE_ERASE_THRESHOLD)
> +#define BF_BCH_MODE_ERASE_THRESHOLD(v)               \
> +     (((v) << BP_BCH_MODE_ERASE_THRESHOLD) & BM_BCH_MODE_ERASE_THRESHOLD)
> +
>  #define HW_BCH_ENCODEPTR                     0x00000030
>  #define HW_BCH_DATAPTR                               0x00000040
>  #define HW_BCH_METAPTR                               0x00000050
> @@ -125,4 +131,8 @@
>       )
>
>  #define HW_BCH_VERSION                               0x00000160
> +#define HW_BCH_DEBUG1                                0x00000170
> +#define BP_BCH_DEBUG1_ERASED_ZERO_COUNT      0
> +#define BM_BCH_DEBUG1_ERASED_ZERO_COUNT              \
> +             (0x1ff << BP_BCH_DEBUG1_ERASED_ZERO_COUNT)
>  #endif
> diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
> index 1f26a79..0548d84 100644
> --- a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
> +++ b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
> @@ -298,6 +298,11 @@ int bch_set_geometry(struct gpmi_nand_data *this)
>                       | BF_BCH_FLASH0LAYOUT1_DATAN_SIZE(block_size, this),
>                       r->bch_regs + HW_BCH_FLASH0LAYOUT1);
>
> +     /* Set erase threshold to ecc_strength for mx6qp and mx7 */
> +     if (GPMI_IS_MX6QP(this) || GPMI_IS_MX7(this))
> +             writel(BF_BCH_MODE_ERASE_THRESHOLD(ecc_strength),
> +                     r->bch_regs + HW_BCH_MODE);
> +
>       /* Set *all* chip selects to use layout 0. */
>       writel(0, r->bch_regs + HW_BCH_LAYOUTSELECT);
>
> diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
> index 9f67f0f..9dea56e 100644
> --- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
> +++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
> @@ -71,6 +71,12 @@ static const struct gpmi_devdata gpmi_devdata_imx6q = {
>       .max_chain_delay = 12,
>  };
>
> +static const struct gpmi_devdata gpmi_devdata_imx6qp = {
> +     .type = IS_MX6QP,
> +     .bch_max_ecc_strength = 40,
> +     .max_chain_delay = 12,
> +};
> +
>  static const struct gpmi_devdata gpmi_devdata_imx6sx = {
>       .type = IS_MX6SX,
>       .bch_max_ecc_strength = 62,
> @@ -1010,6 +1016,7 @@ static int gpmi_ecc_read_page(struct mtd_info *mtd, struct nand_chip *chip,
>  {
>       struct gpmi_nand_data *this = chip->priv;
>       struct bch_geometry *nfc_geo = &this->bch_geometry;
> +     void __iomem *bch_regs = this->resources.bch_regs;
>       void          *payload_virt;
>       dma_addr_t    payload_phys;
>       void          *auxiliary_virt;
> @@ -1018,6 +1025,7 @@ static int gpmi_ecc_read_page(struct mtd_info *mtd, struct nand_chip *chip,
>       unsigned char *status;
>       unsigned int  max_bitflips = 0;
>       int           ret;
> +     int flag = 0;
>
>       dev_dbg(this->dev, "page number is : %d\n", page);
>       ret = read_page_prepare(this, buf, nfc_geo->payload_size,
> @@ -1050,9 +1058,16 @@ static int gpmi_ecc_read_page(struct mtd_info *mtd, struct nand_chip *chip,
>       status = auxiliary_virt + nfc_geo->auxiliary_status_offset;
>
>       for (i = 0; i < nfc_geo->ecc_chunk_count; i++, status++) {
> -             if ((*status == STATUS_GOOD) || (*status == STATUS_ERASED))
> +             if (*status == STATUS_GOOD)
>                       continue;
>
> +             if (*status == STATUS_ERASED) {
> +                     if (GPMI_IS_MX6QP(this) || GPMI_IS_MX7(this))
> +                             if (readl(bch_regs + HW_BCH_DEBUG1))
> +                                     flag = 1;
> +                     continue;
> +             }
> +
>               if (*status == STATUS_UNCORRECTABLE) {
>                       mtd->ecc_stats.failed++;
>                       continue;
> @@ -1081,6 +1096,10 @@ static int gpmi_ecc_read_page(struct mtd_info *mtd, struct nand_chip *chip,
>                       nfc_geo->payload_size,
>                       payload_virt, payload_phys);
>
> +     /* if bitflip occurred in erased page, change data to all 0xff */
> +     if (flag)
> +             memset(buf, 0xff, nfc_geo->payload_size);
> +
>       return max_bitflips;
>  }
>
> @@ -1990,6 +2009,9 @@ static const struct of_device_id gpmi_nand_id_table[] = {
>               .compatible = "fsl,imx6q-gpmi-nand",
>               .data = &gpmi_devdata_imx6q,
>       }, {
> +             .compatible = "fsl,imx6qp-gpmi-nand",
> +             .data = (void *)&gpmi_devdata_imx6qp,
> +     }, {
>               .compatible = "fsl,imx6sx-gpmi-nand",
>               .data = &gpmi_devdata_imx6sx,
>       }, {
> diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-nand.h b/drivers/mtd/nand/gpmi-nand/gpmi-nand.h
> index 58b3d69..149a442 100644
> --- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.h
> +++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.h
> @@ -123,6 +123,7 @@ enum gpmi_type {
>       IS_MX23,
>       IS_MX28,
>       IS_MX6Q,
> +     IS_MX6QP,
>       IS_MX6SX,
>       IS_MX7D,
>  };
> @@ -306,9 +307,11 @@ void gpmi_copy_bits(u8 *dst, size_t dst_bit_off,
>  #define GPMI_IS_MX23(x)              ((x)->devdata->type == IS_MX23)
>  #define GPMI_IS_MX28(x)              ((x)->devdata->type == IS_MX28)
>  #define GPMI_IS_MX6Q(x)              ((x)->devdata->type == IS_MX6Q)
> +#define GPMI_IS_MX6QP(x)     ((x)->devdata->type == IS_MX6QP)
>  #define GPMI_IS_MX6SX(x)     ((x)->devdata->type == IS_MX6SX)
>  #define GPMI_IS_MX7D(x)              ((x)->devdata->type == IS_MX7D)
>
> -#define GPMI_IS_MX6(x)               (GPMI_IS_MX6Q(x) || GPMI_IS_MX6SX(x))
> +#define GPMI_IS_MX6(x)               (GPMI_IS_MX6Q(x) || GPMI_IS_MX6QP(x)\
> +        || GPMI_IS_MX6SX(x))
>  #define GPMI_IS_MX7(x)               (GPMI_IS_MX7D(x))
>  #endif
> --
> 1.9.1
>
Very good feature.

Acked-by: Huang Shijie <shijie.huang at arm.com>
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