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@bootlin.com Reviewed-by: Stefan Roese sr@denx.de --- drivers/mtd/mtdpart.c | 61 ++++++++++++++++++++++++++++++++++ include/linux/mtd/partitions.h | 2 ++ 2 files changed, 63 insertions(+)
diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c index eecdb650ad..09427b7b87 100644 --- a/drivers/mtd/mtdpart.c +++ b/drivers/mtd/mtdpart.c @@ -263,6 +263,67 @@ 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 - mtd_id; + else + mtd_id_len = &mtdids[strlen(mtdids)] - mtd_id + 1; + + 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