Subject: Re: [PATCH v6 14/18] mtd: nand: Add more parameters to the nand_ecc_props structure

From: Boris Brezillon <[email-masked]>
Date: Thu, 28 May 2020 16:34:24 +0200

On Thu, 28 May 2020 13:31:09 +0200
Miquel Raynal <[email-masked]> wrote:

> Prepare the migration to the generic ECC framework by adding more
> fields to the nand_ecc_props structure which will be used widely to
> describe different kind of ECC properties.
> 
> Doing this imposes to move the engine type, ECC placement and
> algorithm enumerations in a shared place: nand.h.
> 
> Signed-off-by: Miquel Raynal <[email-masked]>
> ---
>  include/linux/mtd/nand.h    | 52 +++++++++++++++++++++++++++++++++++++
>  include/linux/mtd/rawnand.h | 44 -------------------------------
>  2 files changed, 52 insertions(+), 44 deletions(-)
> 
> diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
> index 6add464fd18b..2e9af24936cd 100644
> --- a/include/linux/mtd/nand.h
> +++ b/include/linux/mtd/nand.h
> @@ -127,14 +127,66 @@ struct nand_page_io_req {
>  	int mode;
>  };
>  
> +/**
> + * enum nand_ecc_engine_type - NAND ECC engine type
> + * @NAND_ECC_ENGINE_TYPE_INVALID: Invalid value
> + * @NAND_ECC_ENGINE_TYPE_NONE: No ECC correction
> + * @NAND_ECC_ENGINE_TYPE_SOFT: Software ECC correction
> + * @NAND_ECC_ENGINE_TYPE_ON_HOST: On host hardware ECC correction
> + * @NAND_ECC_ENGINE_TYPE_ON_DIE: On chip hardware ECC correction
> + */
> +enum nand_ecc_engine_type {
> +	NAND_ECC_ENGINE_TYPE_INVALID,
> +	NAND_ECC_ENGINE_TYPE_NONE,
> +	NAND_ECC_ENGINE_TYPE_SOFT,
> +	NAND_ECC_ENGINE_TYPE_ON_HOST,
> +	NAND_ECC_ENGINE_TYPE_ON_DIE,
> +};
> +
> +/**
> + * enum nand_ecc_placement - NAND ECC bytes placement
> + * @NAND_ECC_PLACEMENT_UNKNOWN: The actual position of the ECC bytes is unknown
> + * @NAND_ECC_PLACEMENT_OOB: The ECC bytes are located in the OOB area
> + * @NAND_ECC_PLACEMENT_INTERLEAVED: Syndrome layout, there are ECC bytes
> + *                                  interleaved with regular data in the main
> + *                                  area
> + */
> +enum nand_ecc_placement {
> +	NAND_ECC_PLACEMENT_UNKNOWN,
> +	NAND_ECC_PLACEMENT_OOB,
> +	NAND_ECC_PLACEMENT_INTERLEAVED,
> +};
> +
> +/**
> + * enum nand_ecc_algo - NAND ECC algorithm
> + * @NAND_ECC_ALGO_UNKNOWN: Unknown algorithm
> + * @NAND_ECC_ALGO_HAMMING: Hamming algorithm
> + * @NAND_ECC_ALGO_BCH: Bose-Chaudhuri-Hocquenghem algorithm
> + * @NAND_ECC_ALGO_RS: Reed-Solomon algorithm
> + */
> +enum nand_ecc_algo {
> +	NAND_ECC_ALGO_UNKNOWN,
> +	NAND_ECC_ALGO_HAMMING,
> +	NAND_ECC_ALGO_BCH,
> +	NAND_ECC_ALGO_RS,
> +};
> +
>  /**
>   * struct nand_ecc_props - NAND ECC properties
> + * @engine_type: ECC engine type
> + * @placement: OOB placement (if relevant)
> + * @algo: ECC algorithm (if relevant)
>   * @strength: ECC strength
>   * @step_size: Number of bytes per step
> + * @flags: Misc properties

I'd like to hear more about that one. What is this about? I'd rather
not add a field if it's not needed.

>   */
>  struct nand_ecc_props {
> +	enum nand_ecc_engine_type engine_type;
> +	enum nand_ecc_placement placement;
> +	enum nand_ecc_algo algo;
>  	unsigned int strength;
>  	unsigned int step_size;
> +	unsigned int flags;
>  };
>  
>  #define NAND_ECCREQ(str, stp) { .strength = (str), .step_size = (stp) }
> diff --git a/include/linux/mtd/rawnand.h b/include/linux/mtd/rawnand.h
> index c3411a08ce61..8f7f1cce3b4b 100644
> --- a/include/linux/mtd/rawnand.h
> +++ b/include/linux/mtd/rawnand.h
> @@ -92,50 +92,6 @@ enum nand_ecc_mode {
>  	NAND_ECC_ON_DIE,
>  };
>  
> -/**
> - * enum nand_ecc_engine_type - NAND ECC engine type
> - * @NAND_ECC_ENGINE_TYPE_INVALID: Invalid value
> - * @NAND_ECC_ENGINE_TYPE_NONE: No ECC correction
> - * @NAND_ECC_ENGINE_TYPE_SOFT: Software ECC correction
> - * @NAND_ECC_ENGINE_TYPE_ON_HOST: On host hardware ECC correction
> - * @NAND_ECC_ENGINE_TYPE_ON_DIE: On chip hardware ECC correction
> - */
> -enum nand_ecc_engine_type {
> -	NAND_ECC_ENGINE_TYPE_INVALID,
> -	NAND_ECC_ENGINE_TYPE_NONE,
> -	NAND_ECC_ENGINE_TYPE_SOFT,
> -	NAND_ECC_ENGINE_TYPE_ON_HOST,
> -	NAND_ECC_ENGINE_TYPE_ON_DIE,
> -};
> -
> -/**
> - * enum nand_ecc_placement - NAND ECC bytes placement
> - * @NAND_ECC_PLACEMENT_UNKNOWN: The actual position of the ECC bytes is unknown
> - * @NAND_ECC_PLACEMENT_OOB: The ECC bytes are located in the OOB area
> - * @NAND_ECC_PLACEMENT_INTERLEAVED: Syndrome layout, there are ECC bytes
> - *                                  interleaved with regular data in the main
> - *                                  area
> - */
> -enum nand_ecc_placement {
> -	NAND_ECC_PLACEMENT_UNKNOWN,
> -	NAND_ECC_PLACEMENT_OOB,
> -	NAND_ECC_PLACEMENT_INTERLEAVED,
> -};
> -
> -/**
> - * enum nand_ecc_algo - NAND ECC algorithm
> - * @NAND_ECC_ALGO_UNKNOWN: Unknown algorithm
> - * @NAND_ECC_ALGO_HAMMING: Hamming algorithm
> - * @NAND_ECC_ALGO_BCH: Bose-Chaudhuri-Hocquenghem algorithm
> - * @NAND_ECC_ALGO_RS: Reed-Solomon algorithm
> - */
> -enum nand_ecc_algo {
> -	NAND_ECC_ALGO_UNKNOWN,
> -	NAND_ECC_ALGO_HAMMING,
> -	NAND_ECC_ALGO_BCH,
> -	NAND_ECC_ALGO_RS,
> -};
> -
>  /*
>   * Constants for Hardware ECC
>   */

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