[U-Boot] [PATCH v7 08/13] mtd: uclass: search for an equivalent MTD name with the mtdids

[Stefan Roese]

On 31.08.2018 16:57, Miquel Raynal wrote:
> Using an MTD device (resp. partition) name in mtdparts is simple and
> straightforward. However, for a long time already, another name was
> given in mtdparts to indicate a device (resp. partition) so the
> "mtdids" environment variable was created to do the match.
> 
> Let's create a function that, from an MTD device (resp. partition)
> name, search for the equivalent name in the "mtdparts" environment
> variable thanks to the "mtdids" string.
> 
> Signed-off-by: Miquel Raynal <miquel.raynal at bootlin.com>
> ---
>   drivers/mtd/mtdpart.c          | 62 ++++++++++++++++++++++++++++++++++
>   include/linux/mtd/partitions.h |  2 ++
>   2 files changed, 64 insertions(+)
> 
> diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
> index d9708da2ae..096351e48b 100644
> --- a/drivers/mtd/mtdpart.c
> +++ b/drivers/mtd/mtdpart.c
> @@ -263,6 +263,68 @@ int mtd_parse_partitions(struct mtd_info *parent, const char **_mtdparts,
>   	return 0;
>   }
>   
> +/**
> + * mtd_search_alternate_name - Search an alternate name for @mtdname thanks to
> + *                             the mtdids legacy environment variable.
> + *
> + * The mtdids string is a list of comma-separated 'dev_id=mtd_id' tupples.
> + * Check if one of the mtd_id matches mtdname, in this case save dev_id in
> + * altname.
> + *
> + * @mtdname: Current MTD device name
> + * @altname: Alternate name to return
> + * @max_len: Length of the alternate name buffer
> + *
> + * @return 0 on success, an error otherwise.
> + */
> +int mtd_search_alternate_name(const char *mtdname, char *altname,
> +			      unsigned int max_len)
> +{
> +	const char *mtdids, *equal, *comma, *dev_id, *mtd_id;
> +	int dev_id_len, mtd_id_len;
> +
> +	mtdids = env_get("mtdids");
> +	if (!mtdids)
> +		return -EINVAL;
> +
> +	do {
> +		/* Find the '=' sign */
> +		dev_id = mtdids;
> +		equal = strchr(dev_id, '=');
> +		if (!equal)
> +			break;
> +
> +		dev_id_len = equal - mtdids;
> +		mtd_id = equal + 1;
> +
> +		/* Find the end of the tupple */
> +		comma = strchr(mtdids, ',');
> +		if (comma)
> +			mtd_id_len = comma - equal;
> +		else
> +			mtd_id_len = &mtdids[strlen(mtdids)] - equal;
> +
> +		if (!dev_id_len || !mtd_id_len)
> +			return -EINVAL;
> +
> +		if (dev_id_len + 1 > max_len)
> +			continue;
> +
> +		/* Compare the name we search with the current mtd_id */
> +		if (!strncmp(mtdname, mtd_id, mtd_id_len)) {
> +			strncpy(altname, dev_id, dev_id_len);
> +			altname[dev_id_len] = 0;
> +
> +			return 0;
> +		}
> +
> +		/* Go to the next tupple */
> +		mtdids = comma + 1;
> +	} while (comma);
> +
> +	return -EINVAL;
> +}
> +
>   /*
>    * MTD methods which simply translate the effective address and pass through
>    * to the _real_ device.
> diff --git a/include/linux/mtd/partitions.h b/include/linux/mtd/partitions.h
> index ed4ece5e13..082a4966ea 100644
> --- a/include/linux/mtd/partitions.h
> +++ b/include/linux/mtd/partitions.h
> @@ -88,5 +88,7 @@ int mtd_del_partition(struct mtd_info *master, int partno);
>   uint64_t mtd_get_device_size(const struct mtd_info *mtd);
>   int mtd_parse_partitions(struct mtd_info *parent, const char **_mtdparts,
>   			 struct mtd_partition **_parts, int *_nb_parts);
> +int mtd_search_alternate_name(const char *mtdname, char *altname,
> +			      unsigned int max_len);
>   
>   #endif
> 

Reviewed-by: Stefan Roese <sr at denx.de>

Thanks,
Stefan