xref: /linux/block/partitions/acorn.c (revision 4b132aacb0768ac1e652cf517097ea6f237214b9)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  Copyright (c) 1996-2000 Russell King.
4  *
5  *  Scan ADFS partitions on hard disk drives.  Unfortunately, there
6  *  isn't a standard for partitioning drives on Acorn machines, so
7  *  every single manufacturer of SCSI and IDE cards created their own
8  *  method.
9  */
10 #include <linux/buffer_head.h>
11 #include <linux/adfs_fs.h>
12 
13 #include "check.h"
14 
15 /*
16  * Partition types. (Oh for reusability)
17  */
18 #define PARTITION_RISCIX_MFM	1
19 #define PARTITION_RISCIX_SCSI	2
20 #define PARTITION_LINUX		9
21 
22 #if defined(CONFIG_ACORN_PARTITION_CUMANA) || \
23 	defined(CONFIG_ACORN_PARTITION_ADFS)
24 static struct adfs_discrecord *
25 adfs_partition(struct parsed_partitions *state, char *name, char *data,
26 	       unsigned long first_sector, int slot)
27 {
28 	struct adfs_discrecord *dr;
29 	unsigned int nr_sects;
30 
31 	if (adfs_checkbblk(data))
32 		return NULL;
33 
34 	dr = (struct adfs_discrecord *)(data + 0x1c0);
35 
36 	if (dr->disc_size == 0 && dr->disc_size_high == 0)
37 		return NULL;
38 
39 	nr_sects = (le32_to_cpu(dr->disc_size_high) << 23) |
40 		   (le32_to_cpu(dr->disc_size) >> 9);
41 
42 	if (name) {
43 		strlcat(state->pp_buf, " [", PAGE_SIZE);
44 		strlcat(state->pp_buf, name, PAGE_SIZE);
45 		strlcat(state->pp_buf, "]", PAGE_SIZE);
46 	}
47 	put_partition(state, slot, first_sector, nr_sects);
48 	return dr;
49 }
50 #endif
51 
52 #ifdef CONFIG_ACORN_PARTITION_RISCIX
53 
54 struct riscix_part {
55 	__le32	start;
56 	__le32	length;
57 	__le32	one;
58 	char	name[16];
59 };
60 
61 struct riscix_record {
62 	__le32	magic;
63 #define RISCIX_MAGIC	cpu_to_le32(0x4a657320)
64 	__le32	date;
65 	struct riscix_part part[8];
66 };
67 
68 #if defined(CONFIG_ACORN_PARTITION_CUMANA) || \
69 	defined(CONFIG_ACORN_PARTITION_ADFS)
70 static int riscix_partition(struct parsed_partitions *state,
71 			    unsigned long first_sect, int slot,
72 			    unsigned long nr_sects)
73 {
74 	Sector sect;
75 	struct riscix_record *rr;
76 
77 	rr = read_part_sector(state, first_sect, &sect);
78 	if (!rr)
79 		return -1;
80 
81 	strlcat(state->pp_buf, " [RISCiX]", PAGE_SIZE);
82 
83 
84 	if (rr->magic == RISCIX_MAGIC) {
85 		unsigned long size = nr_sects > 2 ? 2 : nr_sects;
86 		int part;
87 
88 		strlcat(state->pp_buf, " <", PAGE_SIZE);
89 
90 		put_partition(state, slot++, first_sect, size);
91 		for (part = 0; part < 8; part++) {
92 			if (rr->part[part].one &&
93 			    memcmp(rr->part[part].name, "All\0", 4)) {
94 				put_partition(state, slot++,
95 					le32_to_cpu(rr->part[part].start),
96 					le32_to_cpu(rr->part[part].length));
97 				strlcat(state->pp_buf, "(", PAGE_SIZE);
98 				strlcat(state->pp_buf, rr->part[part].name, PAGE_SIZE);
99 				strlcat(state->pp_buf, ")", PAGE_SIZE);
100 			}
101 		}
102 
103 		strlcat(state->pp_buf, " >\n", PAGE_SIZE);
104 	} else {
105 		put_partition(state, slot++, first_sect, nr_sects);
106 	}
107 
108 	put_dev_sector(sect);
109 	return slot;
110 }
111 #endif
112 #endif
113 
114 #define LINUX_NATIVE_MAGIC 0xdeafa1de
115 #define LINUX_SWAP_MAGIC   0xdeafab1e
116 
117 struct linux_part {
118 	__le32 magic;
119 	__le32 start_sect;
120 	__le32 nr_sects;
121 };
122 
123 #if defined(CONFIG_ACORN_PARTITION_CUMANA) || \
124 	defined(CONFIG_ACORN_PARTITION_ADFS)
125 static int linux_partition(struct parsed_partitions *state,
126 			   unsigned long first_sect, int slot,
127 			   unsigned long nr_sects)
128 {
129 	Sector sect;
130 	struct linux_part *linuxp;
131 	unsigned long size = nr_sects > 2 ? 2 : nr_sects;
132 
133 	strlcat(state->pp_buf, " [Linux]", PAGE_SIZE);
134 
135 	put_partition(state, slot++, first_sect, size);
136 
137 	linuxp = read_part_sector(state, first_sect, &sect);
138 	if (!linuxp)
139 		return -1;
140 
141 	strlcat(state->pp_buf, " <", PAGE_SIZE);
142 	while (linuxp->magic == cpu_to_le32(LINUX_NATIVE_MAGIC) ||
143 	       linuxp->magic == cpu_to_le32(LINUX_SWAP_MAGIC)) {
144 		if (slot == state->limit)
145 			break;
146 		put_partition(state, slot++, first_sect +
147 				 le32_to_cpu(linuxp->start_sect),
148 				 le32_to_cpu(linuxp->nr_sects));
149 		linuxp ++;
150 	}
151 	strlcat(state->pp_buf, " >", PAGE_SIZE);
152 
153 	put_dev_sector(sect);
154 	return slot;
155 }
156 #endif
157 
158 #ifdef CONFIG_ACORN_PARTITION_CUMANA
159 int adfspart_check_CUMANA(struct parsed_partitions *state)
160 {
161 	unsigned long first_sector = 0;
162 	unsigned int start_blk = 0;
163 	Sector sect;
164 	unsigned char *data;
165 	char *name = "CUMANA/ADFS";
166 	int first = 1;
167 	int slot = 1;
168 
169 	/*
170 	 * Try Cumana style partitions - sector 6 contains ADFS boot block
171 	 * with pointer to next 'drive'.
172 	 *
173 	 * There are unknowns in this code - is the 'cylinder number' of the
174 	 * next partition relative to the start of this one - I'm assuming
175 	 * it is.
176 	 *
177 	 * Also, which ID did Cumana use?
178 	 *
179 	 * This is totally unfinished, and will require more work to get it
180 	 * going. Hence it is totally untested.
181 	 */
182 	do {
183 		struct adfs_discrecord *dr;
184 		unsigned int nr_sects;
185 
186 		data = read_part_sector(state, start_blk * 2 + 6, &sect);
187 		if (!data)
188 			return -1;
189 
190 		if (slot == state->limit)
191 			break;
192 
193 		dr = adfs_partition(state, name, data, first_sector, slot++);
194 		if (!dr)
195 			break;
196 
197 		name = NULL;
198 
199 		nr_sects = (data[0x1fd] + (data[0x1fe] << 8)) *
200 			   (dr->heads + (dr->lowsector & 0x40 ? 1 : 0)) *
201 			   dr->secspertrack;
202 
203 		if (!nr_sects)
204 			break;
205 
206 		first = 0;
207 		first_sector += nr_sects;
208 		start_blk += nr_sects >> (BLOCK_SIZE_BITS - 9);
209 		nr_sects = 0; /* hmm - should be partition size */
210 
211 		switch (data[0x1fc] & 15) {
212 		case 0: /* No partition / ADFS? */
213 			break;
214 
215 #ifdef CONFIG_ACORN_PARTITION_RISCIX
216 		case PARTITION_RISCIX_SCSI:
217 			/* RISCiX - we don't know how to find the next one. */
218 			slot = riscix_partition(state, first_sector, slot,
219 						nr_sects);
220 			break;
221 #endif
222 
223 		case PARTITION_LINUX:
224 			slot = linux_partition(state, first_sector, slot,
225 					       nr_sects);
226 			break;
227 		}
228 		put_dev_sector(sect);
229 		if (slot == -1)
230 			return -1;
231 	} while (1);
232 	put_dev_sector(sect);
233 	return first ? 0 : 1;
234 }
235 #endif
236 
237 #ifdef CONFIG_ACORN_PARTITION_ADFS
238 /*
239  * Purpose: allocate ADFS partitions.
240  *
241  * Params : hd		- pointer to gendisk structure to store partition info.
242  *	    dev		- device number to access.
243  *
244  * Returns: -1 on error, 0 for no ADFS boot sector, 1 for ok.
245  *
246  * Alloc  : hda  = whole drive
247  *	    hda1 = ADFS partition on first drive.
248  *	    hda2 = non-ADFS partition.
249  */
250 int adfspart_check_ADFS(struct parsed_partitions *state)
251 {
252 	unsigned long start_sect, nr_sects, sectscyl, heads;
253 	Sector sect;
254 	unsigned char *data;
255 	struct adfs_discrecord *dr;
256 	unsigned char id;
257 	int slot = 1;
258 
259 	data = read_part_sector(state, 6, &sect);
260 	if (!data)
261 		return -1;
262 
263 	dr = adfs_partition(state, "ADFS", data, 0, slot++);
264 	if (!dr) {
265 		put_dev_sector(sect);
266     		return 0;
267 	}
268 
269 	heads = dr->heads + ((dr->lowsector >> 6) & 1);
270 	sectscyl = dr->secspertrack * heads;
271 	start_sect = ((data[0x1fe] << 8) + data[0x1fd]) * sectscyl;
272 	id = data[0x1fc] & 15;
273 	put_dev_sector(sect);
274 
275 	/*
276 	 * Work out start of non-adfs partition.
277 	 */
278 	nr_sects = get_capacity(state->disk) - start_sect;
279 
280 	if (start_sect) {
281 		switch (id) {
282 #ifdef CONFIG_ACORN_PARTITION_RISCIX
283 		case PARTITION_RISCIX_SCSI:
284 		case PARTITION_RISCIX_MFM:
285 			riscix_partition(state, start_sect, slot,
286 						nr_sects);
287 			break;
288 #endif
289 
290 		case PARTITION_LINUX:
291 			linux_partition(state, start_sect, slot,
292 					       nr_sects);
293 			break;
294 		}
295 	}
296 	strlcat(state->pp_buf, "\n", PAGE_SIZE);
297 	return 1;
298 }
299 #endif
300 
301 #ifdef CONFIG_ACORN_PARTITION_ICS
302 
303 struct ics_part {
304 	__le32 start;
305 	__le32 size;
306 };
307 
308 static int adfspart_check_ICSLinux(struct parsed_partitions *state,
309 				   unsigned long block)
310 {
311 	Sector sect;
312 	unsigned char *data = read_part_sector(state, block, &sect);
313 	int result = 0;
314 
315 	if (data) {
316 		if (memcmp(data, "LinuxPart", 9) == 0)
317 			result = 1;
318 		put_dev_sector(sect);
319 	}
320 
321 	return result;
322 }
323 
324 /*
325  * Check for a valid ICS partition using the checksum.
326  */
327 static inline int valid_ics_sector(const unsigned char *data)
328 {
329 	unsigned long sum;
330 	int i;
331 
332 	for (i = 0, sum = 0x50617274; i < 508; i++)
333 		sum += data[i];
334 
335 	sum -= le32_to_cpu(*(__le32 *)(&data[508]));
336 
337 	return sum == 0;
338 }
339 
340 /*
341  * Purpose: allocate ICS partitions.
342  * Params : hd		- pointer to gendisk structure to store partition info.
343  *	    dev		- device number to access.
344  * Returns: -1 on error, 0 for no ICS table, 1 for partitions ok.
345  * Alloc  : hda  = whole drive
346  *	    hda1 = ADFS partition 0 on first drive.
347  *	    hda2 = ADFS partition 1 on first drive.
348  *		..etc..
349  */
350 int adfspart_check_ICS(struct parsed_partitions *state)
351 {
352 	const unsigned char *data;
353 	const struct ics_part *p;
354 	int slot;
355 	Sector sect;
356 
357 	/*
358 	 * Try ICS style partitions - sector 0 contains partition info.
359 	 */
360 	data = read_part_sector(state, 0, &sect);
361 	if (!data)
362 	    	return -1;
363 
364 	if (!valid_ics_sector(data)) {
365 	    	put_dev_sector(sect);
366 		return 0;
367 	}
368 
369 	strlcat(state->pp_buf, " [ICS]", PAGE_SIZE);
370 
371 	for (slot = 1, p = (const struct ics_part *)data; p->size; p++) {
372 		u32 start = le32_to_cpu(p->start);
373 		s32 size = le32_to_cpu(p->size); /* yes, it's signed. */
374 
375 		if (slot == state->limit)
376 			break;
377 
378 		/*
379 		 * Negative sizes tell the RISC OS ICS driver to ignore
380 		 * this partition - in effect it says that this does not
381 		 * contain an ADFS filesystem.
382 		 */
383 		if (size < 0) {
384 			size = -size;
385 
386 			/*
387 			 * Our own extension - We use the first sector
388 			 * of the partition to identify what type this
389 			 * partition is.  We must not make this visible
390 			 * to the filesystem.
391 			 */
392 			if (size > 1 && adfspart_check_ICSLinux(state, start)) {
393 				start += 1;
394 				size -= 1;
395 			}
396 		}
397 
398 		if (size)
399 			put_partition(state, slot++, start, size);
400 	}
401 
402 	put_dev_sector(sect);
403 	strlcat(state->pp_buf, "\n", PAGE_SIZE);
404 	return 1;
405 }
406 #endif
407 
408 #ifdef CONFIG_ACORN_PARTITION_POWERTEC
409 struct ptec_part {
410 	__le32 unused1;
411 	__le32 unused2;
412 	__le32 start;
413 	__le32 size;
414 	__le32 unused5;
415 	char type[8];
416 };
417 
418 static inline int valid_ptec_sector(const unsigned char *data)
419 {
420 	unsigned char checksum = 0x2a;
421 	int i;
422 
423 	/*
424 	 * If it looks like a PC/BIOS partition, then it
425 	 * probably isn't PowerTec.
426 	 */
427 	if (data[510] == 0x55 && data[511] == 0xaa)
428 		return 0;
429 
430 	for (i = 0; i < 511; i++)
431 		checksum += data[i];
432 
433 	return checksum == data[511];
434 }
435 
436 /*
437  * Purpose: allocate ICS partitions.
438  * Params : hd		- pointer to gendisk structure to store partition info.
439  *	    dev		- device number to access.
440  * Returns: -1 on error, 0 for no ICS table, 1 for partitions ok.
441  * Alloc  : hda  = whole drive
442  *	    hda1 = ADFS partition 0 on first drive.
443  *	    hda2 = ADFS partition 1 on first drive.
444  *		..etc..
445  */
446 int adfspart_check_POWERTEC(struct parsed_partitions *state)
447 {
448 	Sector sect;
449 	const unsigned char *data;
450 	const struct ptec_part *p;
451 	int slot = 1;
452 	int i;
453 
454 	data = read_part_sector(state, 0, &sect);
455 	if (!data)
456 		return -1;
457 
458 	if (!valid_ptec_sector(data)) {
459 		put_dev_sector(sect);
460 		return 0;
461 	}
462 
463 	strlcat(state->pp_buf, " [POWERTEC]", PAGE_SIZE);
464 
465 	for (i = 0, p = (const struct ptec_part *)data; i < 12; i++, p++) {
466 		u32 start = le32_to_cpu(p->start);
467 		u32 size = le32_to_cpu(p->size);
468 
469 		if (size)
470 			put_partition(state, slot++, start, size);
471 	}
472 
473 	put_dev_sector(sect);
474 	strlcat(state->pp_buf, "\n", PAGE_SIZE);
475 	return 1;
476 }
477 #endif
478 
479 #ifdef CONFIG_ACORN_PARTITION_EESOX
480 struct eesox_part {
481 	char	magic[6];
482 	char	name[10];
483 	__le32	start;
484 	__le32	unused6;
485 	__le32	unused7;
486 	__le32	unused8;
487 };
488 
489 /*
490  * Guess who created this format?
491  */
492 static const char eesox_name[] = {
493 	'N', 'e', 'i', 'l', ' ',
494 	'C', 'r', 'i', 't', 'c', 'h', 'e', 'l', 'l', ' ', ' '
495 };
496 
497 /*
498  * EESOX SCSI partition format.
499  *
500  * This is a goddamned awful partition format.  We don't seem to store
501  * the size of the partition in this table, only the start addresses.
502  *
503  * There are two possibilities where the size comes from:
504  *  1. The individual ADFS boot block entries that are placed on the disk.
505  *  2. The start address of the next entry.
506  */
507 int adfspart_check_EESOX(struct parsed_partitions *state)
508 {
509 	Sector sect;
510 	const unsigned char *data;
511 	unsigned char buffer[256];
512 	struct eesox_part *p;
513 	sector_t start = 0;
514 	int i, slot = 1;
515 
516 	data = read_part_sector(state, 7, &sect);
517 	if (!data)
518 		return -1;
519 
520 	/*
521 	 * "Decrypt" the partition table.  God knows why...
522 	 */
523 	for (i = 0; i < 256; i++)
524 		buffer[i] = data[i] ^ eesox_name[i & 15];
525 
526 	put_dev_sector(sect);
527 
528 	for (i = 0, p = (struct eesox_part *)buffer; i < 8; i++, p++) {
529 		sector_t next;
530 
531 		if (memcmp(p->magic, "Eesox", 6))
532 			break;
533 
534 		next = le32_to_cpu(p->start);
535 		if (i)
536 			put_partition(state, slot++, start, next - start);
537 		start = next;
538 	}
539 
540 	if (i != 0) {
541 		sector_t size;
542 
543 		size = get_capacity(state->disk);
544 		put_partition(state, slot++, start, size - start);
545 		strlcat(state->pp_buf, "\n", PAGE_SIZE);
546 	}
547 
548 	return i ? 1 : 0;
549 }
550 #endif
551