1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2013 HUAWEI
4 * Author: Cai Zhiyong <caizhiyong@huawei.com>
6 * Read block device partition table from the command line.
7 * Typically used for fixed block (eMMC) embedded devices.
8 * It has no MBR, so saves storage space. Bootloader can be easily accessed
9 * by absolute address of data on the block device.
10 * Users can easily change the partition.
12 * The format for the command line is just like mtdparts.
14 * For further information, see "Documentation/block/cmdline-partition.txt"
18 #include <linux/cmdline-parser.h>
24 static struct cmdline_parts *bdev_parts;
26 static int add_part(int slot, struct cmdline_subpart *subpart, void *param)
29 struct partition_meta_info *info;
30 char tmp[sizeof(info->volname) + 4];
31 struct parsed_partitions *state = (struct parsed_partitions *)param;
33 if (slot >= state->limit)
36 put_partition(state, slot, subpart->from >> 9,
39 info = &state->parts[slot].info;
41 label_min = min_t(int, sizeof(info->volname) - 1,
42 sizeof(subpart->name));
43 strncpy(info->volname, subpart->name, label_min);
44 info->volname[label_min] = '\0';
46 snprintf(tmp, sizeof(tmp), "(%s)", info->volname);
47 strlcat(state->pp_buf, tmp, PAGE_SIZE);
49 state->parts[slot].has_info = true;
54 static int __init cmdline_parts_setup(char *s)
59 __setup("blkdevparts=", cmdline_parts_setup);
62 * Purpose: allocate cmdline partitions.
64 * -1 if unable to read the partition table
65 * 0 if this isn't our partition table
68 int cmdline_partition(struct parsed_partitions *state)
71 char bdev[BDEVNAME_SIZE];
72 struct cmdline_parts *parts;
76 cmdline_parts_free(&bdev_parts);
78 if (cmdline_parts_parse(&bdev_parts, cmdline)) {
88 bdevname(state->bdev, bdev);
89 parts = cmdline_parts_find(bdev_parts, bdev);
93 disk_size = get_capacity(state->bdev->bd_disk) << 9;
95 cmdline_parts_set(parts, disk_size, 1, add_part, (void *)state);
97 strlcat(state->pp_buf, "\n", PAGE_SIZE);