Re: [PATCH v7 28/28] mtd: rawnand: Allocate the interface configurations dynamically

[Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>]

On Fri, 29 May 2020 13:13:22 +0200
Miquel Raynal <miquel.raynal@xxxxxxxxxxx> wrote:

> Instead of manipulating the statically allocated structure and copy
> timings around, allocate one at identification time and save it in the
> nand_chip structure once it has been initialized.
> 
> All NAND chips using the same interface configuration during reset and
> startup, we define a helper to retrieve a single reset interface
> configuration object, shared across all NAND chips.
> 
> We use a second pointer to always have a reference on the currently
> applied interface configuration, which may either point to the "best
> interface configuration" or to the "default reset interface
> configuration".
> 
> Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
> ---
>  drivers/mtd/nand/raw/nand_base.c    | 59 +++++++++++++++++++----------
>  drivers/mtd/nand/raw/nand_timings.c |  6 +++
>  include/linux/mtd/rawnand.h         | 14 +++++--
>  3 files changed, 56 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
> index 753328f106c1..9912a3afa1c9 100644
> --- a/drivers/mtd/nand/raw/nand_base.c
> +++ b/drivers/mtd/nand/raw/nand_base.c
> @@ -928,9 +928,9 @@ 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);
> +	chip->current_interface_config = nand_get_reset_interface();
> +	ret = ops->setup_interface(chip, chipnr,
> +				   chip->current_interface_config);
>  	if (ret)
>  		pr_err("Failed to configure data interface to SDR timing mode 0\n");
>  
> @@ -949,7 +949,8 @@ static int nand_reset_interface(struct nand_chip *chip, int chipnr)
>   */
>  static int nand_setup_interface(struct nand_chip *chip, int chipnr)
>  {
> -	u8 mode = chip->interface_config.timings.mode;
> +	const struct nand_controller_ops *ops = chip->controller->ops;
> +	u8 mode = chip->best_interface_config->timings.mode;
>  	u8 tmode_param[ONFI_SUBFEATURE_PARAM_LEN] = { mode, };
>  	int ret;
>  
> @@ -967,14 +968,13 @@ static int nand_setup_interface(struct nand_chip *chip, int chipnr)
>  	}
>  
>  	/* Change the mode on the controller side */
> -	ret = chip->controller->ops->setup_interface(chip, chipnr,
> -						     &chip->interface_config);
> +	ret = ops->setup_interface(chip, chipnr, chip->best_interface_config);
>  	if (ret)
>  		return ret;
>  
>  	/* Check the mode has been accepted by the chip, if supported */
>  	if (!nand_supports_get_features(chip, ONFI_FEATURE_ADDR_TIMING_MODE))
> -		return 0;
> +		goto update_interface_config;
>  
>  	memset(tmode_param, 0, ONFI_SUBFEATURE_PARAM_LEN);
>  	nand_select_target(chip, chipnr);
> @@ -990,6 +990,9 @@ static int nand_setup_interface(struct nand_chip *chip, int chipnr)
>  		goto err_reset_chip;
>  	}
>  
> +update_interface_config:
> +	chip->current_interface_config = chip->best_interface_config;
> +
>  	return 0;
>  
>  err_reset_chip:
> @@ -1031,8 +1034,10 @@ int nand_choose_best_sdr_timings(struct nand_chip *chip,
>  		/* Verify the controller supports the requested interface */
>  		ret = ops->setup_interface(chip, NAND_DATA_IFACE_CHECK_ONLY,
>  					   iface);
> -		if (!ret)
> +		if (!ret) {
> +			chip->best_interface_config = iface;
>  			return ret;
> +		}
>  
>  		/* Fallback to slower modes */
>  		best_mode = iface->timings.mode;
> @@ -1046,9 +1051,11 @@ int nand_choose_best_sdr_timings(struct nand_chip *chip,
>  		ret = ops->setup_interface(chip, NAND_DATA_IFACE_CHECK_ONLY,
>  					   iface);
>  		if (!ret)
> -			return 0;
> +			break;
>  	}
>  
> +	chip->best_interface_config = iface;
> +
>  	return 0;
>  }
>  
> @@ -1067,15 +1074,25 @@ int nand_choose_best_sdr_timings(struct nand_chip *chip,
>   */
>  static int nand_choose_interface_config(struct nand_chip *chip)
>  {
> +	struct nand_interface_config *iface;
> +	int ret;
> +
>  	if (!nand_controller_can_setup_interface(chip))
>  		return 0;
>  
> +	iface = kzalloc(sizeof(*iface), GFP_KERNEL);
> +	if (!iface)
> +		return -ENOMEM;
> +
>  	if (chip->ops.choose_interface_config)
> -		return chip->ops.choose_interface_config(chip,
> -							 &chip->interface_config);
> +		ret = chip->ops.choose_interface_config(chip, iface);
> +	else
> +		ret = nand_choose_best_sdr_timings(chip, iface, NULL);
>  
> -	return nand_choose_best_sdr_timings(chip, &chip->interface_config,
> -					    NULL);
> +	if (ret)
> +		kfree(iface);
> +
> +	return ret;
>  }
>  
>  /**
> @@ -2501,7 +2518,6 @@ 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);
> @@ -2526,11 +2542,9 @@ 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 (!chip->best_interface_config)
>  		return 0;
>  
> -	chip->interface_config = saved_intf_config;
>  	ret = nand_setup_interface(chip, chipnr);
>  	if (ret)
>  		return ret;
> @@ -5198,7 +5212,7 @@ static int nand_scan_ident(struct nand_chip *chip, unsigned int maxchips,
>  	mutex_init(&chip->lock);
>  
>  	/* Enforce the right timings for reset/detection */
> -	onfi_fill_interface_config(chip, &chip->interface_config, NAND_SDR_IFACE, 0);
> +	chip->current_interface_config = nand_get_reset_interface();
>  
>  	ret = nand_dt_init(chip);
>  	if (ret)
> @@ -5994,7 +6008,7 @@ static int nand_scan_tail(struct nand_chip *chip)
>  	for (i = 0; i < nanddev_ntargets(&chip->base); i++) {
>  		ret = nand_setup_interface(chip, i);
>  		if (ret)
> -			goto err_nanddev_cleanup;
> +			goto err_free_interface_config;
>  	}
>  
>  	/* Check, if we should skip the bad block table scan */
> @@ -6004,10 +6018,12 @@ static int nand_scan_tail(struct nand_chip *chip)
>  	/* Build bad block table */
>  	ret = nand_create_bbt(chip);
>  	if (ret)
> -		goto err_nanddev_cleanup;
> +		goto err_free_interface_config;
>  
>  	return 0;
>  
> +err_free_interface_config:
> +	kfree(chip->best_interface_config);
>  
>  err_nanddev_cleanup:
>  	nanddev_cleanup(&chip->base);
> @@ -6101,6 +6117,9 @@ void nand_cleanup(struct nand_chip *chip)
>  			& NAND_BBT_DYNAMICSTRUCT)
>  		kfree(chip->badblock_pattern);
>  
> +	/* Free the data interface */
> +	kfree(chip->best_interface_config);
> +
>  	/* Free manufacturer priv data. */
>  	nand_manufacturer_cleanup(chip);
>  
> diff --git a/drivers/mtd/nand/raw/nand_timings.c b/drivers/mtd/nand/raw/nand_timings.c
> index 1e22006c79ba..d999f48ca105 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 a2427c67d38b..219086e56d76 100644
> --- a/include/linux/mtd/rawnand.h
> +++ b/include/linux/mtd/rawnand.h
> @@ -1069,7 +1069,11 @@ struct nand_manufacturer {
>   * @options: Various chip options. They can partly be set to inform nand_scan
>   *           about special functionality. See the defines for further
>   *           explanation.
> - * @interface_config: NAND interface timing information
> + * @current_interface_config: The currently used NAND interface configuration
> + * @best_interface_config: The best NAND interface configuration which fits both
> + *                         the NAND chip and NAND controller constraints. If
> + *                         unset, the default reset interface configuration must
> + *                         be used.
>   * @bbt_erase_shift: Number of address bits in a bbt entry
>   * @bbt_options: Bad block table specific options. All options used here must
>   *               come from bbm.h. By default, these options will be copied to
> @@ -1116,7 +1120,8 @@ struct nand_chip {
>  	unsigned int options;
>  
>  	/* Data interface */
> -	struct nand_interface_config interface_config;
> +	const struct nand_interface_config *current_interface_config;
> +	struct nand_interface_config *best_interface_config;
>  
>  	/* Bad block information */
>  	unsigned int bbt_erase_shift;
> @@ -1201,6 +1206,9 @@ 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);

nand_get_reset_interface_config(), and I'm not sure you need to
expose that one. I'd expect it to be used only by the core.

> +
>  /**
>   * nand_get_interface_config - Retrieve the current interface configuration
>   *                             of a NAND chip
> @@ -1209,7 +1217,7 @@ static inline struct device_node *nand_get_flash_node(struct nand_chip *chip)
>  static inline const struct nand_interface_config *
>  nand_get_interface_config(struct nand_chip *chip)
>  {
> -	return &chip->interface_config;
> +	return chip->current_interface_config;
>  }
>  
>  /*


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