xref: /openbmc/linux/block/partitions/sgi.c (revision a08aa9bc)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  fs/partitions/sgi.c
4  *
5  *  Code extracted from drivers/block/genhd.c
6  */
7 
8 #include "check.h"
9 
10 #define SGI_LABEL_MAGIC 0x0be5a941
11 
12 enum {
13 	LINUX_RAID_PARTITION = 0xfd,	/* autodetect RAID partition */
14 };
15 
16 struct sgi_disklabel {
17 	__be32 magic_mushroom;		/* Big fat spliff... */
18 	__be16 root_part_num;		/* Root partition number */
19 	__be16 swap_part_num;		/* Swap partition number */
20 	s8 boot_file[16];		/* Name of boot file for ARCS */
21 	u8 _unused0[48];		/* Device parameter useless crapola.. */
22 	struct sgi_volume {
23 		s8 name[8];		/* Name of volume */
24 		__be32 block_num;		/* Logical block number */
25 		__be32 num_bytes;		/* How big, in bytes */
26 	} volume[15];
27 	struct sgi_partition {
28 		__be32 num_blocks;		/* Size in logical blocks */
29 		__be32 first_block;	/* First logical block */
30 		__be32 type;		/* Type of this partition */
31 	} partitions[16];
32 	__be32 csum;			/* Disk label checksum */
33 	__be32 _unused1;			/* Padding */
34 };
35 
sgi_partition(struct parsed_partitions * state)36 int sgi_partition(struct parsed_partitions *state)
37 {
38 	int i, csum;
39 	__be32 magic;
40 	int slot = 1;
41 	unsigned int start, blocks;
42 	__be32 *ui, cs;
43 	Sector sect;
44 	struct sgi_disklabel *label;
45 	struct sgi_partition *p;
46 
47 	label = read_part_sector(state, 0, &sect);
48 	if (!label)
49 		return -1;
50 	p = &label->partitions[0];
51 	magic = label->magic_mushroom;
52 	if(be32_to_cpu(magic) != SGI_LABEL_MAGIC) {
53 		/*printk("Dev %s SGI disklabel: bad magic %08x\n",
54 		       state->disk->disk_name, be32_to_cpu(magic));*/
55 		put_dev_sector(sect);
56 		return 0;
57 	}
58 	ui = ((__be32 *) (label + 1)) - 1;
59 	for(csum = 0; ui >= ((__be32 *) label);) {
60 		cs = *ui--;
61 		csum += be32_to_cpu(cs);
62 	}
63 	if(csum) {
64 		printk(KERN_WARNING "Dev %s SGI disklabel: csum bad, label corrupted\n",
65 		       state->disk->disk_name);
66 		put_dev_sector(sect);
67 		return 0;
68 	}
69 	/* All SGI disk labels have 16 partitions, disks under Linux only
70 	 * have 15 minor's.  Luckily there are always a few zero length
71 	 * partitions which we don't care about so we never overflow the
72 	 * current_minor.
73 	 */
74 	for(i = 0; i < 16; i++, p++) {
75 		blocks = be32_to_cpu(p->num_blocks);
76 		start  = be32_to_cpu(p->first_block);
77 		if (blocks) {
78 			put_partition(state, slot, start, blocks);
79 			if (be32_to_cpu(p->type) == LINUX_RAID_PARTITION)
80 				state->parts[slot].flags = ADDPART_FLAG_RAID;
81 		}
82 		slot++;
83 	}
84 	strlcat(state->pp_buf, "\n", PAGE_SIZE);
85 	put_dev_sector(sect);
86 	return 1;
87 }
88