Re: [PATCH v7 22/28] mtd: rawnand: Add the ->choose_interface_config() hook

[Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>]

On Fri, 29 May 2020 13:13:16 +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>

Reviewed-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>

> ---
>  drivers/mtd/nand/raw/nand_base.c | 18 +++++++++++-------
>  include/linux/mtd/rawnand.h      |  3 +++
>  2 files changed, 14 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
> index 956a66fdccb8..2f4eba1a1082 100644
> --- a/drivers/mtd/nand/raw/nand_base.c
> +++ b/drivers/mtd/nand/raw/nand_base.c
> @@ -1049,7 +1049,6 @@ int nand_choose_best_sdr_timings(struct nand_chip *chip,
>  		}
>  	}
>  
> -

Still this unrelated blank line removal :-).

>  	for (mode = best_mode; mode >= 0; mode--) {
>  		onfi_fill_interface_config(chip, iface, NAND_SDR_IFACE, mode);
>  
> @@ -1067,18 +1066,23 @@ 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.
> - * First tries to retrieve supported timing modes from ONFI information,
> - * and if the NAND chip does not support ONFI, relies on the
> - * ->onfi_timing_mode_default specified in the nand_ids table. After this
> - * function nand_chip->interface_ is initialized with the best timing mode
> - * available.
> + * and the driver. Eventually let the NAND manufacturer driver propose his own
> + * set of timings.
> + *
> + * After this function nand_chip->interface_config is initialized with the best
> + * timing mode available.
> + *
> + * Returns 0 for success or negative error code otherwise.
>   */
>  static int nand_choose_interface_config(struct nand_chip *chip)
>  {
>  	if (!nand_controller_can_setup_interface(chip))
>  		return 0;
>  
> +	if (chip->ops.choose_interface_config)
> +		return chip->ops.choose_interface_config(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 2ca56eef0f07..316a02189da1 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_interface_config: Choose the best interface configuration
>   */
>  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_config)(struct nand_chip *chip,
> +				       struct nand_interface_config *iface);
>  };
>  
>  /**


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