bootargs 之 mtdparts

Uboot:  bootargs  mtdparts=4m(kernel:0),25856k(rootfs:0) 设置分区Uboot传给内核mtdparts分区表优先级高于在flash在设备树中的分区表/** * mtd_device_parse_register - parse partitions and register an MTD device. * * @mtd: the MTD device to register * @types: the list of MTD partition probes to try, see *         'parse_mtd_partitions()' for more information * @parser_data: MTD partition parser-specific data * @parts: fallback partition information to register, if parsing fails; *         only valid if %nr_parts > %0 * @nr_parts: the number of partitions in parts, if zero then the full *            MTD device is registered if no partition info is found * * This function aggregates MTD partitions parsing (done by * 'parse_mtd_partitions()') and MTD device and partitions registering. It * basically follows the most common pattern found in many MTD drivers: * * * It first tries to probe partitions on MTD device @mtd using parsers *   specified in @types (if @types is %NULL, then the default list of parsers *   is used, see 'parse_mtd_partitions()' for more information). If none are *   found this functions tries to fallback to information specified in *   @parts/@nr_parts. * * If any partitioning info was found, this function registers the found *   partitions. * * If no partitions were found this function just registers the MTD device *   @mtd and exits. * * Returns zero in case of success and a negative error code in case of failure. */int mtd_device_parse_register(struct mtd_info *mtd, const char * const *types,      struct mtd_part_parser_data *parser_data,      const struct mtd_partition *parts,      int nr_parts){int err;struct mtd_partition *real_parts;//首先尝试从mtdparts获取分区表err = parse_mtd_partitions(mtd, types, &real_parts, parser_data);if (err <= 0 && nr_parts && parts) {//其次从flash所在设备树结点获取分区表real_parts = kmemdup(parts, sizeof(*parts) * nr_parts,     GFP_KERNEL);if (!real_parts)err = -ENOMEM;elseerr = nr_parts;}//建立分区设备if (err > 0) {err = add_mtd_partitions(mtd, real_parts, err);kfree(real_parts);} else if (err == 0) {err = add_mtd_device(mtd);if (err == 1)err = -ENODEV;}return err;}