[PATCH v2] mtd: rawnand: nand_base: Handle algorithm selection

[Michael Nazzareno Trimarchi]

Hi

On Wed, Mar 8, 2023 at 10:29 PM Linus Walleij <linus.walleij at linaro.org> wrote:
>
> For BRCMNAND with 1-bit BCH ECC (BCH-1) such as used on the
> D-Link DIR-885L and DIR-890L routers, we need to explicitly
> select the ECC like this in the device tree:
>
>   nand-ecc-algo = "bch";
>   nand-ecc-strength = <1>;
>   nand-ecc-step-size = <512>;
>
> This is handled by the Linux kernel but U-Boot core does
> not respect this. Fix it up by parsing the algorithm and
> preserve the behaviour using this property to select
> software BCH as far as possible.
>
> Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
> ---
> ChangeLog v1->v2:
> - Drop pointless check for ecc_algo >= 0, it is always
>   >= 0.
> ---
>  drivers/mtd/nand/raw/nand_base.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
> index 9eba360d55f3..c173fd09237a 100644
> --- a/drivers/mtd/nand/raw/nand_base.c
> +++ b/drivers/mtd/nand/raw/nand_base.c
> @@ -4487,6 +4487,7 @@ EXPORT_SYMBOL(nand_detect);
>  static int nand_dt_init(struct mtd_info *mtd, struct nand_chip *chip, ofnode node)
>  {
>         int ret, ecc_mode = -1, ecc_strength, ecc_step;
> +       int ecc_algo = NAND_ECC_UNKNOWN;
>         const char *str;
>
>         ret = ofnode_read_s32_default(node, "nand-bus-width", -1);
> @@ -4512,10 +4513,13 @@ static int nand_dt_init(struct mtd_info *mtd, struct nand_chip *chip, ofnode nod
>                         ecc_mode = NAND_ECC_SOFT_BCH;
>         }
>
> -       if (ecc_mode == NAND_ECC_SOFT) {
> -               str = ofnode_read_string(node, "nand-ecc-algo");
> -               if (str && !strcmp(str, "bch"))
> +       str = ofnode_read_string(node, "nand-ecc-algo");
> +       if (str && !strcmp(str, "bch")) {
> +               ecc_algo = NAND_ECC_BCH;
> +               if (ecc_mode == NAND_ECC_SOFT)
>                         ecc_mode = NAND_ECC_SOFT_BCH;
> +       } else if (!strcmp(str, "hamming")) {
> +               ecc_algo = NAND_ECC_HAMMING;
>         }
>
>         ecc_strength = ofnode_read_s32_default(node,
> @@ -4529,6 +4533,8 @@ static int nand_dt_init(struct mtd_info *mtd, struct nand_chip *chip, ofnode nod
>                 return -EINVAL;
>         }
>
> +       chip->ecc.algo = ecc_algo;
> +
>         if (ecc_mode >= 0)
>                 chip->ecc.mode = ecc_mode;
>
> --
> 2.39.1
>
Reviewed-by: Michael Trimarchi <michael at amarulasolutions.com>

Michael