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)
24static struct adfs_discrecord *
25adfs_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
54struct riscix_part {
55	__le32	start;
56	__le32	length;
57	__le32	one;
58	char	name[16];
59};
60
61struct 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)
70static 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
117struct 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)
125static 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
159int 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 */
250int 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
303struct ics_part {
304	__le32 start;
305	__le32 size;
306};
307
308static 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 */
327static 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 */
350int 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
409struct ptec_part {
410	__le32 unused1;
411	__le32 unused2;
412	__le32 start;
413	__le32 size;
414	__le32 unused5;
415	char type[8];
416};
417
418static 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 */
446int 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
480struct 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 */
492static 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 */
507int 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