1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 *  fs/partitions/amiga.c
  4 *
  5 *  Code extracted from drivers/block/genhd.c
  6 *
  7 *  Copyright (C) 1991-1998  Linus Torvalds
  8 *  Re-organised Feb 1998 Russell King
  9 */
 10
 11#define pr_fmt(fmt) fmt
 12
 13#include <linux/types.h>
 14#include <linux/affs_hardblocks.h>
 15
 16#include "check.h"
 17
 18static __inline__ u32
 19checksum_block(__be32 *m, int size)
 20{
 21	u32 sum = 0;
 22
 23	while (size--)
 24		sum += be32_to_cpu(*m++);
 25	return sum;
 26}
 27
 28int amiga_partition(struct parsed_partitions *state)
 29{
 30	Sector sect;
 31	unsigned char *data;
 32	struct RigidDiskBlock *rdb;
 33	struct PartitionBlock *pb;
 34	int start_sect, nr_sects, blk, part, res = 0;
 35	int blksize = 1;	/* Multiplier for disk block size */
 36	int slot = 1;
 37
 38	for (blk = 0; ; blk++, put_dev_sector(sect)) {
 39		if (blk == RDB_ALLOCATION_LIMIT)
 40			goto rdb_done;
 41		data = read_part_sector(state, blk, &sect);
 42		if (!data) {
 43			pr_err("Dev %s: unable to read RDB block %d\n",
 44			       state->disk->disk_name, blk);
 45			res = -1;
 46			goto rdb_done;
 47		}
 48		if (*(__be32 *)data != cpu_to_be32(IDNAME_RIGIDDISK))
 49			continue;
 50
 51		rdb = (struct RigidDiskBlock *)data;
 52		if (checksum_block((__be32 *)data, be32_to_cpu(rdb->rdb_SummedLongs) & 0x7F) == 0)
 53			break;
 54		/* Try again with 0xdc..0xdf zeroed, Windows might have
 55		 * trashed it.
 56		 */
 57		*(__be32 *)(data+0xdc) = 0;
 58		if (checksum_block((__be32 *)data,
 59				be32_to_cpu(rdb->rdb_SummedLongs) & 0x7F)==0) {
 60			pr_err("Trashed word at 0xd0 in block %d ignored in checksum calculation\n",
 61			       blk);
 62			break;
 63		}
 64
 65		pr_err("Dev %s: RDB in block %d has bad checksum\n",
 66		       state->disk->disk_name, blk);
 67	}
 68
 69	/* blksize is blocks per 512 byte standard block */
 70	blksize = be32_to_cpu( rdb->rdb_BlockBytes ) / 512;
 71
 72	{
 73		char tmp[7 + 10 + 1 + 1];
 74
 75		/* Be more informative */
 76		snprintf(tmp, sizeof(tmp), " RDSK (%d)", blksize * 512);
 77		strlcat(state->pp_buf, tmp, PAGE_SIZE);
 78	}
 79	blk = be32_to_cpu(rdb->rdb_PartitionList);
 80	put_dev_sector(sect);
 81	for (part = 1; blk>0 && part<=16; part++, put_dev_sector(sect)) {
 82		blk *= blksize;	/* Read in terms partition table understands */
 83		data = read_part_sector(state, blk, &sect);
 84		if (!data) {
 85			pr_err("Dev %s: unable to read partition block %d\n",
 86			       state->disk->disk_name, blk);
 87			res = -1;
 88			goto rdb_done;
 89		}
 90		pb  = (struct PartitionBlock *)data;
 91		blk = be32_to_cpu(pb->pb_Next);
 92		if (pb->pb_ID != cpu_to_be32(IDNAME_PARTITION))
 93			continue;
 94		if (checksum_block((__be32 *)pb, be32_to_cpu(pb->pb_SummedLongs) & 0x7F) != 0 )
 95			continue;
 96
 97		/* Tell Kernel about it */
 98
 99		nr_sects = (be32_to_cpu(pb->pb_Environment[10]) + 1 -
100			    be32_to_cpu(pb->pb_Environment[9])) *
101			   be32_to_cpu(pb->pb_Environment[3]) *
102			   be32_to_cpu(pb->pb_Environment[5]) *
103			   blksize;
104		if (!nr_sects)
105			continue;
106		start_sect = be32_to_cpu(pb->pb_Environment[9]) *
107			     be32_to_cpu(pb->pb_Environment[3]) *
108			     be32_to_cpu(pb->pb_Environment[5]) *
109			     blksize;
110		put_partition(state,slot++,start_sect,nr_sects);
111		{
112			/* Be even more informative to aid mounting */
113			char dostype[4];
114			char tmp[42];
115
116			__be32 *dt = (__be32 *)dostype;
117			*dt = pb->pb_Environment[16];
118			if (dostype[3] < ' ')
119				snprintf(tmp, sizeof(tmp), " (%c%c%c^%c)",
120					dostype[0], dostype[1],
121					dostype[2], dostype[3] + '@' );
122			else
123				snprintf(tmp, sizeof(tmp), " (%c%c%c%c)",
124					dostype[0], dostype[1],
125					dostype[2], dostype[3]);
126			strlcat(state->pp_buf, tmp, PAGE_SIZE);
127			snprintf(tmp, sizeof(tmp), "(res %d spb %d)",
128				be32_to_cpu(pb->pb_Environment[6]),
129				be32_to_cpu(pb->pb_Environment[4]));
130			strlcat(state->pp_buf, tmp, PAGE_SIZE);
131		}
132		res = 1;
133	}
134	strlcat(state->pp_buf, "\n", PAGE_SIZE);
135
136rdb_done:
137	return res;
138}