1/* $NetBSD: dkwedge_tos.c,v 1.2 2024/04/06 09:51:34 hannken Exp $ */
2
3/*
4 * Copyright (c) 2024 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Charlotte Koch.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32/*
33 * dk(4) support for Atari "TOS" partition schemes.
34 *
35 * Technical details taken from:
36 *
37 * - "Atari Hard Disk File Systems Reference Guide" v1.2b by Jean
38 * Louis-Guerin (DrCoolZic) (September 2014)
39 *
40 * https://info-coach.fr/atari/documents/_mydoc/Atari_HD_File_Sytem_Reference_Guide.pdf
41 */
42
43#include <sys/buf.h>
44#include <sys/disk.h>
45#include <sys/endian.h>
46#include <sys/vnode.h>
47
48#define TOS_PART_TYPE_LEN	3
49#define TOS_GEM_PARTITION	"GEM"
50#define TOS_BGM_PARTITION	"BGM"
51#define TOS_XGM_PARTITION	"XGM"
52
53#define TOS_CXNMETHOD_SASI	0x00
54#define TOS_CXNMETHOD_SCSI	0xFF
55
56#define TOS_MAX_PART_COUNT	4
57#define TOS_SECTOR_SIZE		512
58
59struct tos_partition {
60	uint8_t status;
61	char type[TOS_PART_TYPE_LEN];
62	uint32_t offset;
63	uint32_t size;
64} __packed;
65__CTASSERT(sizeof(struct tos_partition) == 12);
66
67struct tos_root_sector {
68	uint8_t unused1[441];
69	uint8_t connection_method;
70	uint8_t unused2[8];
71	uint32_t size;
72	struct tos_partition parts[TOS_MAX_PART_COUNT];
73	uint8_t unused3[10];
74} __packed;
75__CTASSERT(sizeof(struct tos_root_sector) == TOS_SECTOR_SIZE);
76
77static int dkwedge_discover_tos(struct disk *pdk, struct vnode *vp);
78
79static int
80dkwedge_discover_tos(struct disk *pdk, struct vnode *vp)
81{
82	struct dkwedge_info dkw;
83	int error = 0;
84	size_t i;
85	char safe_type[4];
86
87	/* Get ourselves a fistful of memory. */
88	buf_t *bp = geteblk(TOS_SECTOR_SIZE);
89
90	error = dkwedge_read(pdk, vp, 0L, bp->b_data, TOS_SECTOR_SIZE);
91	if (error) {
92		aprint_error("unable to read TOS Root Sector: error = %d",
93		    error);
94		goto out;
95	}
96
97	struct tos_root_sector *trs = bp->b_data;
98
99	/*
100	 * If the "connection method" isn't recognized, then this is
101	 * probably NOT an Atari-style partition, so get outta here. Note
102	 * that there really isn't a magic number we can rely on; this check
103	 * is somewhat made up. But at least it's better than nothing.
104	 */
105	switch (trs->connection_method) {
106	case TOS_CXNMETHOD_SASI: /* FALLTHROUGH */
107	case TOS_CXNMETHOD_SCSI:
108		; /* OK */
109		break;
110	default:
111		error = ESRCH;
112		goto out;
113	}
114
115	/*
116	 * Make a wedge for each partition that exists (i.e., has the "exist"
117	 * bit set).
118	 */
119	for (i = 0; i < TOS_MAX_PART_COUNT; i++) {
120		struct tos_partition part = trs->parts[i];
121
122		if (!(part.status & 0x01))
123			continue;
124
125		/* Ignore if we see it's an extended "XGM" partition. */
126		if (!strncmp(part.type, TOS_XGM_PARTITION, TOS_PART_TYPE_LEN)) {
127			aprint_normal(
128			    "WARNING: XGM partitions are not yet supported\n");
129			continue;
130		}
131
132		/*
133		 * Otherwise, get outta here if it's not the partition-types
134		 * we *do* support.
135		 */
136		if (strncmp(part.type, TOS_GEM_PARTITION, TOS_PART_TYPE_LEN) &&
137		    strncmp(part.type, TOS_BGM_PARTITION, TOS_PART_TYPE_LEN)) {
138			error = ESRCH;
139			goto out;
140		}
141
142		memset(&dkw, 0, sizeof(dkw));
143		memset(safe_type, 0, sizeof(safe_type));
144
145		/*
146		 * The partition type string is NOT NUL-terminated, so let's
147		 * play it safe.
148		 */
149		memcpy(safe_type, part.type, TOS_PART_TYPE_LEN);
150		safe_type[TOS_PART_TYPE_LEN] = '\0';
151
152		/* Finally, make the wedge. */
153		snprintf(dkw.dkw_wname, sizeof(dkw.dkw_wname), "ATARI_%s_%02zu",
154		    safe_type, i);
155		dkw.dkw_offset = be32toh(trs->parts[i].offset);
156		dkw.dkw_size = be32toh(trs->parts[i].size);
157		strlcpy(dkw.dkw_ptype, DKW_PTYPE_FAT, sizeof(dkw.dkw_ptype));
158		strlcpy(dkw.dkw_parent, pdk->dk_name, sizeof(dkw.dkw_parent));
159		error = dkwedge_add(&dkw);
160
161		if (error == EEXIST) {
162			aprint_error("partition named \"%s\" already exists",
163			    dkw.dkw_wname);
164			goto out;
165		}
166	}
167
168	error = 0;
169
170out:
171	brelse(bp, 0);
172	return error;
173}
174
175DKWEDGE_DISCOVERY_METHOD_DECL(TOS, 10, dkwedge_discover_tos);
176