Re: [PATCH v6 24/30] mtd: rawnand: Add the ->choose_interface() hook

[Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>]

On Fri, 29 May 2020 01:16:06 +0200
Miquel Raynal <miquel.raynal@xxxxxxxxxxx> wrote:

> This hook can be overloaded by NAND manufacturer drivers to propose
> alternative timings when not following the main standards. In this
> case, the manufacturer drivers is responsible for choosing the best
> interface configuration that fits both the controller and chip
> capabilities.
> 
> Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
> ---
>  drivers/mtd/nand/raw/nand_base.c | 9 +++++++--
>  include/linux/mtd/rawnand.h      | 3 +++
>  2 files changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
> index 28e249beb335..132feee3ba13 100644
> --- a/drivers/mtd/nand/raw/nand_base.c
> +++ b/drivers/mtd/nand/raw/nand_base.c
> @@ -1047,7 +1047,6 @@ int nand_choose_best_sdr_timings(struct nand_chip *chip,
>  		}
>  	}
>  
> -
>  	for (mode = best_mode; mode >= 0; mode--) {
>  		onfi_fill_interface_config(chip, iface, NAND_SDR_IFACE, mode);
>  
> @@ -1065,7 +1064,9 @@ int nand_choose_best_sdr_timings(struct nand_chip *chip,
>   * @chip: The NAND chip
>   *
>   * Find the best data interface and NAND timings supported by the chip
> - * and the driver.
> + * and the driver. Eventually let the NAND manufacturer driver propose his own
> + * set of timings.
> + *
>   * After this function nand_chip->data_interface is initialized with the best
>   * timing mode available.
>   *
> @@ -1076,6 +1077,10 @@ static int nand_choose_interface(struct nand_chip *chip)
>  	if (!nand_controller_can_setup_interface(chip))
>  		return 0;
>  
> +	if (chip->ops.choose_interface)
> +		return chip->ops.choose_interface(chip,
> +						  &chip->interface_config);
> +
>  	return nand_choose_best_sdr_timings(chip, &chip->interface_config,
>  					    NULL);
>  }
> diff --git a/include/linux/mtd/rawnand.h b/include/linux/mtd/rawnand.h
> index 03b62f900d20..ce4a525517a6 100644
> --- a/include/linux/mtd/rawnand.h
> +++ b/include/linux/mtd/rawnand.h
> @@ -1033,6 +1033,7 @@ struct nand_legacy {
>   * @lock_area: Lock operation
>   * @unlock_area: Unlock operation
>   * @setup_read_retry: Set the read-retry mode (mostly needed for MLC NANDs)
> + * @choose_data_interface: Choose the best data interface
>   */
>  struct nand_chip_ops {
>  	int (*suspend)(struct nand_chip *chip);
> @@ -1040,6 +1041,8 @@ struct nand_chip_ops {
>  	int (*lock_area)(struct nand_chip *chip, loff_t ofs, uint64_t len);
>  	int (*unlock_area)(struct nand_chip *chip, loff_t ofs, uint64_t len);
>  	int (*setup_read_retry)(struct nand_chip *chip, int retry_mode);
> +	int (*choose_interface)(struct nand_chip *chip,

s/choose_interface/choose_interface_config/

> +				struct nand_interface_config *iface);
>  };
>  
>  /**


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