Re: [PATCH v2 5/6] mtd: nand: gpmi: correct bitflip for erased NAND page

[Andrea Scian <rnd4@dave-tech.it>]

Il 18/08/2015 05:25, Han Xu ha scritto:
> 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 gf/2 and if bitflip detected, GPMI driver will
> correct the data to all 0xFF.

Please also fix the commit message. Once fixed I can add my Reviewed-by 
(for what it's worth ;-) )

>
> Signed-off-by: Han Xu <b45815@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 6b37414..f00ce90 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 0462103..362cf4c 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;
>   }
>
> @@ -1991,6 +2010,9 @@ 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 1e105f1..36ffeda 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
>