[PATCH 2/3] mtd: nand: read (from DT) and store ECC algorithm

[Brian Norris]

On Fri, Feb 12, 2016 at 07:11:24PM +0100, Rafał Miłecki wrote:
> This will allow drivers handle ECC properly.
> 
> Signed-off-by: Rafał Miłecki <zajec5 at gmail.com>
> ---
>  drivers/mtd/nand/nand_base.c | 6 +++++-
>  include/linux/mtd/nand.h     | 1 +
>  2 files changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
> index f2c8ff3..ef977f3 100644
> --- a/drivers/mtd/nand/nand_base.c
> +++ b/drivers/mtd/nand/nand_base.c
> @@ -3979,7 +3979,7 @@ ident_done:
>  static int nand_dt_init(struct nand_chip *chip)
>  {
>  	struct device_node *dn = nand_get_flash_node(chip);
> -	int ecc_mode, ecc_strength, ecc_step;
> +	int ecc_mode, ecc_algo, ecc_strength, ecc_step;
>  
>  	if (!dn)
>  		return 0;
> @@ -3991,6 +3991,7 @@ static int nand_dt_init(struct nand_chip *chip)
>  		chip->bbt_options |= NAND_BBT_USE_FLASH;
>  
>  	ecc_mode = of_get_nand_ecc_mode(dn);
> +	ecc_algo = of_get_nand_ecc_algo(dn);
>  	ecc_strength = of_get_nand_ecc_strength(dn);
>  	ecc_step = of_get_nand_ecc_step_size(dn);
>  
> @@ -4003,6 +4004,9 @@ static int nand_dt_init(struct nand_chip *chip)
>  	if (ecc_mode >= 0)
>  		chip->ecc.mode = ecc_mode;
>  
> +	if (ecc_algo >= 0)
> +		chip->ecc.algo = ecc_algo;
> +

While this might appear to handle the absence of the nand-ecc-algo
property correctly, this isn't safe. This means that any existing DT
without the property will get treated as Hamming ECC. Perhaps we need
the enum to have a 0 value of 'NAND_ECC_ALGO_UNKNOWN' or something like
that?

Brian

>  	if (ecc_strength >= 0)
>  		chip->ecc.strength = ecc_strength;
>  
> diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
> index 25854d2..8deca1b 100644
> --- a/include/linux/mtd/nand.h
> +++ b/include/linux/mtd/nand.h
> @@ -513,6 +513,7 @@ struct nand_hw_control {
>   */
>  struct nand_ecc_ctrl {
>  	nand_ecc_modes_t mode;
> +	enum nand_ecc_algo algo;
>  	int steps;
>  	int size;
>  	int bytes;
> -- 
> 1.8.4.5
>