diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c index 9ccb1b3361..49353b038a 100644 --- a/drivers/mtd/mtdpart.c +++ b/drivers/mtd/mtdpart.c @@ -26,6 +26,7 @@ #include #include #include +#include #include "mtdcore.h" @@ -76,6 +77,215 @@ char *kstrdup(const char *s, gfp_t gfp) } #endif +#define MTD_SIZE_REMAINING (~0LLU) +#define MTD_OFFSET_NOT_SPECIFIED (~0LLU) + +/** + * mtd_parse_partition - Parse @mtdparts partition definition, fill @partition + * with it and update the @mtdparts string pointer. + * + * The partition name is allocated and must be freed by the caller. + * + * This function is widely inspired from part_parse (mtdparts.c). + * + * @mtdparts: String describing the partition with mtdparts command syntax + * @partition: MTD partition structure to fill + * + * @return 0 on success, an error otherwise. + */ +static int mtd_parse_partition(const char **_mtdparts, + struct mtd_partition *partition) +{ + const char *mtdparts = *_mtdparts; + const char *name = NULL; + int name_len; + char *buf; + + /* Ensure the partition structure is empty */ + memset(partition, 0, sizeof(struct mtd_partition)); + + /* Fetch the partition size */ + if (*mtdparts == '-') { + /* Assign all remaining space to this partition */ + partition->size = MTD_SIZE_REMAINING; + mtdparts++; + } else { + partition->size = ustrtoull(mtdparts, (char **)&mtdparts, 0); + if (partition->size < SZ_4K) { + printf("Minimum partition size 4kiB, %lldB requested\n", + partition->size); + return -EINVAL; + } + } + + /* Check for the offset */ + partition->offset = MTD_OFFSET_NOT_SPECIFIED; + if (*mtdparts == '@') { + mtdparts++; + partition->offset = ustrtoull(mtdparts, (char **)&mtdparts, 0); + } + + /* Now look for the name */ + if (*mtdparts == '(') { + name = ++mtdparts; + mtdparts = strchr(name, ')'); + if (!mtdparts) { + printf("No closing ')' found in partition name\n"); + return -EINVAL; + } + name_len = mtdparts - name + 1; + if ((name_len - 1) == 0) { + printf("Empty partition name\n"); + return -EINVAL; + } + mtdparts++; + } else { + /* Name will be of the form size@offset */ + name_len = 22; + } + + /* Check if the partition is read-only */ + if (strncmp(mtdparts, "ro", 2) == 0) { + partition->mask_flags |= MTD_WRITEABLE; + mtdparts += 2; + } + + /* Check for a potential next partition definition */ + if (*mtdparts == ',') { + if (partition->size == MTD_SIZE_REMAINING) { + printf("No partitions allowed after a fill-up\n"); + return -EINVAL; + } + ++mtdparts; + } else if ((*mtdparts == ';') || (*mtdparts == '\0')) { + /* NOP */ + } else { + printf("Unexpected character '%c' in mtdparts\n", *mtdparts); + return -EINVAL; + } + + /* + * Allocate a buffer for the name and either copy the provided name or + * auto-generate it with the form 'size@offset'. + */ + buf = malloc(name_len); + if (!buf) + return -ENOMEM; + + if (name) + strncpy(buf, name, name_len - 1); + else + snprintf(buf, name_len, "0x%08llx@0x%08llx", + partition->size, partition->offset); + + buf[name_len - 1] = '\0'; + partition->name = buf; + + *_mtdparts = mtdparts; + + return 0; +} + +/** + * mtd_parse_partitions - Create a partition array from an mtdparts definition + * + * Stateless function that takes a @parent MTD device, a string @_mtdparts + * describing the partitions (with the "mtdparts" command syntax) and creates + * the corresponding MTD partition structure array @_parts. Both the name and + * the structure partition itself must be freed freed, the caller may use + * @mtd_free_parsed_partitions() for this purpose. + * + * @parent: MTD device which contains the partitions + * @_mtdparts: Pointer to a string describing the partitions with "mtdparts" + * command syntax. + * @_parts: Allocated array containing the partitions, must be freed by the + * caller. + * @_nparts: Size of @_parts array. + * + * @return 0 on success, an error otherwise. + */ +int mtd_parse_partitions(struct mtd_info *parent, const char **_mtdparts, + struct mtd_partition **_parts, int *_nparts) +{ + struct mtd_partition partition = {}, *parts; + const char *mtdparts = *_mtdparts; + int cur_off = 0, cur_sz = 0; + int nparts = 0; + int ret, idx; + u64 sz; + + /* First, iterate over the partitions until we know their number */ + while (mtdparts[0] != '\0' && mtdparts[0] != ';') { + ret = mtd_parse_partition(&mtdparts, &partition); + if (ret) + return ret; + + free((char *)partition.name); + nparts++; + } + + /* Allocate an array of partitions to give back to the caller */ + parts = malloc(sizeof(*parts) * nparts); + if (!parts) { + printf("Not enough space to save partitions meta-data\n"); + return -ENOMEM; + } + + /* Iterate again over each partition to save the data in our array */ + for (idx = 0; idx < nparts; idx++) { + ret = mtd_parse_partition(_mtdparts, &parts[idx]); + if (ret) + return ret; + + if (parts[idx].size == MTD_SIZE_REMAINING) + parts[idx].size = parent->size - cur_sz; + cur_sz += parts[idx].size; + + sz = parts[idx].size; + if (sz < parent->writesize || do_div(sz, parent->writesize)) { + printf("Partition size must be a multiple of %d\n", + parent->writesize); + return -EINVAL; + } + + if (parts[idx].offset == MTD_OFFSET_NOT_SPECIFIED) + parts[idx].offset = cur_off; + cur_off += parts[idx].size; + + parts[idx].ecclayout = parent->ecclayout; + } + + /* Offset by one mtdparts to point to the next device if any */ + if (*_mtdparts[0] == ';') + (*_mtdparts)++; + + *_parts = parts; + *_nparts = nparts; + + return 0; +} + +/** + * mtd_free_parsed_partitions - Free dynamically allocated partitions + * + * Each successful call to @mtd_parse_partitions must be followed by a call to + * @mtd_free_parsed_partitions to free any allocated array during the parsing + * process. + * + * @parts: Array containing the partitions that will be freed. + * @nparts: Size of @parts array. + */ +void mtd_free_parsed_partitions(struct mtd_partition *parts, + unsigned int nparts) +{ + int i; + + for (i = 0; i < nparts; i++) + free((char *)parts[i].name); + + free(parts); +} + /* * 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 ce0e8dbee4..6eea0a547a 100644 --- a/include/linux/mtd/partitions.h +++ b/include/linux/mtd/partitions.h @@ -87,4 +87,25 @@ int mtd_add_partition(struct mtd_info *master, const char *name, int mtd_del_partition(struct mtd_info *master, int partno); uint64_t mtd_get_device_size(const struct mtd_info *mtd); +#if defined(CONFIG_MTD_PARTITIONS) +int mtd_parse_partitions(struct mtd_info *parent, const char **_mtdparts, + struct mtd_partition **_parts, int *_nparts); +void mtd_free_parsed_partitions(struct mtd_partition *parts, + unsigned int nparts); +#else +static inline int +mtd_parse_partitions(struct mtd_info *parent, const char **_mtdparts, + struct mtd_partition **_parts, int *_nparts) +{ + *_nparts = 0; + + return 0; +} +static inline void +mtd_free_parsed_partitions(struct mtd_partition *parts, unsigned int nparts) +{ + return; +} +#endif /* defined(MTD_PARTITIONS) */ + #endif