Re: [PATCH v3 06/16] mtd: rawnand: qcom: use the ecc strength from device parameter

From: Miquel Raynal
Date: Sat May 26 2018 - 04:43:32 EST


Hi Abhishek,

On Fri, 25 May 2018 17:51:34 +0530, Abhishek Sahu
<absahu@xxxxxxxxxxxxxx> wrote:

> Currently the driver uses the ECC strength specified in DT.
> The QPIC/EBI2 NAND supports 4 or 8-bit ECC correction. The same
> kind of board can have different NAND parts so use the ECC
> strength from device parameters if it is not specified in DT.
>
> Signed-off-by: Abhishek Sahu <absahu@xxxxxxxxxxxxxx>
> ---
> * Changes from v2:
> NONE

Yes you did change things:

- s/<< 2/* 4/
- updated the cwperpage location
- the block handling the ecc-step-size property has been removed in a
previous patch

Please be careful with that, it is time consuming to review the patches
all over again.

>
> * Changes from v1:
>
> 1. Removed the custom logic and used the helper fuction.
>
> drivers/mtd/nand/raw/qcom_nandc.c | 29 +++++++++++++++++++++--------
> 1 file changed, 21 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c
> index b538390..7377923 100644
> --- a/drivers/mtd/nand/raw/qcom_nandc.c
> +++ b/drivers/mtd/nand/raw/qcom_nandc.c
> @@ -2315,19 +2315,39 @@ static int qcom_nand_ooblayout_free(struct mtd_info *mtd, int section,
> .free = qcom_nand_ooblayout_free,
> };
>
> +static int
> +qcom_nandc_calc_ecc_bytes(int step_size, int strength)
> +{
> + return strength == 4 ? 12 : 16;
> +}
> +NAND_ECC_CAPS_SINGLE(qcom_nandc_ecc_caps, qcom_nandc_calc_ecc_bytes,
> + NANDC_STEP_SIZE, 4, 8);
> +
> static int qcom_nand_host_setup(struct qcom_nand_host *host)
> {
> struct nand_chip *chip = &host->chip;
> struct mtd_info *mtd = nand_to_mtd(chip);
> struct nand_ecc_ctrl *ecc = &chip->ecc;
> struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
> - int cwperpage, bad_block_byte;
> + int cwperpage, bad_block_byte, ret;
> bool wide_bus;
> int ecc_mode = 1;
>
> /* controller only supports 512 bytes of data in each step */
> ecc->size = NANDC_STEP_SIZE;
> wide_bus = chip->options & NAND_BUSWIDTH_16 ? true : false;
> + cwperpage = mtd->writesize / NANDC_STEP_SIZE;
> +
> + /*
> + * Each CW has 4 available OOB bytes which will be protected with ECC
> + * so remaining bytes can be used for ECC.
> + */
> + ret = nand_ecc_choose_conf(chip, &qcom_nandc_ecc_caps,
> + mtd->oobsize - cwperpage * 4);

Nitpick: could you add parenthesis around (cwperpage * 4) just for
clarity.

> + if (ret) {
> + dev_err(nandc->dev, "No valid ECC settings possible\n");
> + return ret;
> + }
>
> if (ecc->strength >= 8) {
> /* 8 bit ECC defaults to BCH ECC on all platforms */
> @@ -2396,7 +2416,6 @@ static int qcom_nand_host_setup(struct qcom_nand_host *host)
>
> mtd_set_ooblayout(mtd, &qcom_nand_ooblayout_ops);
>
> - cwperpage = mtd->writesize / ecc->size;
> nandc->max_cwperpage = max_t(unsigned int, nandc->max_cwperpage,
> cwperpage);
>
> @@ -2412,12 +2431,6 @@ static int qcom_nand_host_setup(struct qcom_nand_host *host)
> * for 8 bit ECC
> */
> host->cw_size = host->cw_data + ecc->bytes;
> -
> - if (ecc->bytes * (mtd->writesize / ecc->size) > mtd->oobsize) {
> - dev_err(nandc->dev, "ecc data doesn't fit in OOB area\n");
> - return -EINVAL;
> - }
> -
> bad_block_byte = mtd->writesize - host->cw_size * (cwperpage - 1) + 1;
>
> host->cfg0 = (cwperpage - 1) << CW_PER_PAGE

Once corrected:

Acked-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>

Thanks,
MiquÃl