Re: [PATCH v6 19/30] mtd: rawnand: Define a unique reset interface configuration

[Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>]

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

> All NAND chips will always use the same interface configuration for
> reset and at startup: SDR mode 0. Instead of copying around the
> interface configuration, let's just define a helper to retrieve the
> reset interface configuration object.
> 
> Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
> ---
>  drivers/mtd/nand/raw/nand_base.c    | 10 +++-------
>  drivers/mtd/nand/raw/nand_timings.c |  6 ++++++
>  include/linux/mtd/rawnand.h         |  3 +++
>  3 files changed, 12 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
> index 07a7d918b462..4a72ec221262 100644
> --- a/drivers/mtd/nand/raw/nand_base.c
> +++ b/drivers/mtd/nand/raw/nand_base.c
> @@ -928,9 +928,7 @@ static int nand_reset_interface(struct nand_chip *chip, int chipnr)
>  	 * timings to timing mode 0.
>  	 */
>  
> -	onfi_fill_interface_config(chip, &chip->interface_config,
> -				   NAND_SDR_IFACE, 0);
> -	ret = ops->setup_interface(chip, chipnr, &chip->interface_config);
> +	ret = ops->setup_interface(chip, chipnr, nand_get_reset_interface());
>  	if (ret)
>  		pr_err("Failed to configure data interface to SDR timing mode 0\n");
>  
> @@ -2483,7 +2481,6 @@ EXPORT_SYMBOL_GPL(nand_subop_get_data_len);
>   */
>  int nand_reset(struct nand_chip *chip, int chipnr)
>  {
> -	struct nand_interface_config saved_intf_config = chip->interface_config;
>  	int ret;
>  
>  	ret = nand_reset_interface(chip, chipnr);
> @@ -2508,11 +2505,10 @@ int nand_reset(struct nand_chip *chip, int chipnr)
>  	 * nand_setup_interface() uses ->set/get_features() which would
>  	 * fail anyway as the parameter page is not available yet.
>  	 */
> -	if (!memcmp(&chip->interface_config, &saved_intf_config,
> -		    sizeof(saved_intf_config)))
> +	if (!memcmp(&chip->interface_config, nand_get_reset_interface(),
> +		    sizeof(chip->interface_config)))
>  		return 0;
>  
> -	chip->interface_config = saved_intf_config;

Are you sure you can do that now? Looks like the current interface
config is not preserved, and you end up with mode 0 after a reset.

>  	ret = nand_setup_interface(chip, chipnr);
>  	if (ret)
>  		return ret;
> diff --git a/drivers/mtd/nand/raw/nand_timings.c b/drivers/mtd/nand/raw/nand_timings.c
> index 6c12cd52323d..0089196b9e36 100644
> --- a/drivers/mtd/nand/raw/nand_timings.c
> +++ b/drivers/mtd/nand/raw/nand_timings.c
> @@ -292,6 +292,12 @@ static const struct nand_interface_config onfi_sdr_timings[] = {
>  	},
>  };
>  
> +/* All NAND chips share the same reset data interface: SDR mode 0 */
> +const struct nand_interface_config *nand_get_reset_interface(void)
> +{
> +	return &onfi_sdr_timings[0];
> +}
> +
>  /**
>   * onfi_find_closest_sdr_mode - Derive the closest ONFI SDR timing mode given a
>   *                              set of timings
> diff --git a/include/linux/mtd/rawnand.h b/include/linux/mtd/rawnand.h
> index c2fcac38bcc2..b37eb5ee11c8 100644
> --- a/include/linux/mtd/rawnand.h
> +++ b/include/linux/mtd/rawnand.h
> @@ -1202,6 +1202,9 @@ static inline struct device_node *nand_get_flash_node(struct nand_chip *chip)
>  	return mtd_get_of_node(nand_to_mtd(chip));
>  }
>  
> +/* Default/reset data interface */
> +const struct nand_interface_config *nand_get_reset_interface(void);
> +
>  /*
>   * A helper for defining older NAND chips where the second ID byte fully
>   * defined the chip, including the geometry (chip size, eraseblock size, page


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