block/partitions/acorn.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  *  Copyright (c) 1996-2000 Russell King.
  *
  *  Scan ADFS partitions on hard disk drives.  Unfortunately, there
  *  isn't a standard for partitioning drives on Acorn machines, so
  *  every single manufacturer of SCSI and IDE cards created their own
  *  method.
  */
 #include <linux/buffer_head.h>
 #include <linux/adfs_fs.h>

 #include "check.h"

 /*
  * Partition types. (Oh for reusability)
  */
 #define PARTITION_RISCIX_MFM	1
 #define PARTITION_RISCIX_SCSI	2
 #define PARTITION_LINUX		9

 #if defined(CONFIG_ACORN_PARTITION_CUMANA) || \
 	defined(CONFIG_ACORN_PARTITION_ADFS)
 static struct adfs_discrecord *
 adfs_partition(struct parsed_partitions *state, char *name, char *data,
 	       unsigned long first_sector, int slot)
 {
 	struct adfs_discrecord *dr;
 	unsigned int nr_sects;

 	if (adfs_checkbblk(data))
 		return NULL;

 	dr = (struct adfs_discrecord *)(data + 0x1c0);

 	if (dr->disc_size == 0 && dr->disc_size_high == 0)
 		return NULL;

 	nr_sects = (le32_to_cpu(dr->disc_size_high) << 23) |
 		   (le32_to_cpu(dr->disc_size) >> 9);

 	if (name) {
 		strlcat(state->pp_buf, " [", PAGE_SIZE);
 		strlcat(state->pp_buf, name, PAGE_SIZE);
 		strlcat(state->pp_buf, "]", PAGE_SIZE);
 	}
 	put_partition(state, slot, first_sector, nr_sects);
 	return dr;
 }
 #endif

 #ifdef CONFIG_ACORN_PARTITION_RISCIX

 struct riscix_part {
 	__le32	start;
 	__le32	length;
 	__le32	one;
 	char	name[16];
 };

 struct riscix_record {
 	__le32	magic;
 #define RISCIX_MAGIC	cpu_to_le32(0x4a657320)
 	__le32	date;
 	struct riscix_part part[8];
 };

 #if defined(CONFIG_ACORN_PARTITION_CUMANA) || \
 	defined(CONFIG_ACORN_PARTITION_ADFS)
 static int riscix_partition(struct parsed_partitions *state,
 			    unsigned long first_sect, int slot,
 			    unsigned long nr_sects)
 {
 	Sector sect;
 	struct riscix_record *rr;

 	rr = read_part_sector(state, first_sect, &sect);
 	if (!rr)
 		return -1;

 	strlcat(state->pp_buf, " [RISCiX]", PAGE_SIZE);


 	if (rr->magic == RISCIX_MAGIC) {
 		unsigned long size = nr_sects > 2 ? 2 : nr_sects;
 		int part;

 		strlcat(state->pp_buf, " <", PAGE_SIZE);

 		put_partition(state, slot++, first_sect, size);
 		for (part = 0; part < 8; part++) {
 			if (rr->part[part].one &&
 			    memcmp(rr->part[part].name, "All\0", 4)) {
 				put_partition(state, slot++,
 					le32_to_cpu(rr->part[part].start),
 					le32_to_cpu(rr->part[part].length));
 				strlcat(state->pp_buf, "(", PAGE_SIZE);
 				strlcat(state->pp_buf, rr->part[part].name, PAGE_SIZE);
 				strlcat(state->pp_buf, ")", PAGE_SIZE);
 			}
 		}

 		strlcat(state->pp_buf, " >\n", PAGE_SIZE);
 	} else {
 		put_partition(state, slot++, first_sect, nr_sects);
 	}

 	put_dev_sector(sect);
 	return slot;
 }
 #endif
 #endif

 #define LINUX_NATIVE_MAGIC 0xdeafa1de
 #define LINUX_SWAP_MAGIC   0xdeafab1e

 struct linux_part {
 	__le32 magic;
 	__le32 start_sect;
 	__le32 nr_sects;
 };

 #if defined(CONFIG_ACORN_PARTITION_CUMANA) || \
 	defined(CONFIG_ACORN_PARTITION_ADFS)
 static int linux_partition(struct parsed_partitions *state,
 			   unsigned long first_sect, int slot,
 			   unsigned long nr_sects)
 {
 	Sector sect;
 	struct linux_part *linuxp;
 	unsigned long size = nr_sects > 2 ? 2 : nr_sects;

 	strlcat(state->pp_buf, " [Linux]", PAGE_SIZE);

 	put_partition(state, slot++, first_sect, size);

 	linuxp = read_part_sector(state, first_sect, &sect);
 	if (!linuxp)
 		return -1;

 	strlcat(state->pp_buf, " <", PAGE_SIZE);
 	while (linuxp->magic == cpu_to_le32(LINUX_NATIVE_MAGIC) ||
 	       linuxp->magic == cpu_to_le32(LINUX_SWAP_MAGIC)) {
 		if (slot == state->limit)
 			break;
 		put_partition(state, slot++, first_sect +
 				 le32_to_cpu(linuxp->start_sect),
 				 le32_to_cpu(linuxp->nr_sects));
 		linuxp ++;
 	}
 	strlcat(state->pp_buf, " >", PAGE_SIZE);

 	put_dev_sector(sect);
 	return slot;
 }
 #endif

 #ifdef CONFIG_ACORN_PARTITION_CUMANA
 int adfspart_check_CUMANA(struct parsed_partitions *state)
 {
 	unsigned long first_sector = 0;
 	unsigned int start_blk = 0;
 	Sector sect;
 	unsigned char *data;
 	char *name = "CUMANA/ADFS";
 	int first = 1;
 	int slot = 1;

 	/*
 	 * Try Cumana style partitions - sector 6 contains ADFS boot block
 	 * with pointer to next 'drive'.
 	 *
 	 * There are unknowns in this code - is the 'cylinder number' of the
 	 * next partition relative to the start of this one - I'm assuming
 	 * it is.
 	 *
 	 * Also, which ID did Cumana use?
 	 *
 	 * This is totally unfinished, and will require more work to get it
 	 * going. Hence it is totally untested.
 	 */
 	do {
 		struct adfs_discrecord *dr;
 		unsigned int nr_sects;

 		data = read_part_sector(state, start_blk * 2 + 6, &sect);
 		if (!data)
 			return -1;

 		if (slot == state->limit)
 			break;

 		dr = adfs_partition(state, name, data, first_sector, slot++);
 		if (!dr)
 			break;

 		name = NULL;

 		nr_sects = (data[0x1fd] + (data[0x1fe] << 8)) *
 			   (dr->heads + (dr->lowsector & 0x40 ? 1 : 0)) *
 			   dr->secspertrack;

 		if (!nr_sects)
 			break;

 		first = 0;
 		first_sector += nr_sects;
 		start_blk += nr_sects >> (BLOCK_SIZE_BITS - 9);
 		nr_sects = 0; /* hmm - should be partition size */

 		switch (data[0x1fc] & 15) {
 		case 0: /* No partition / ADFS? */
 			break;

 #ifdef CONFIG_ACORN_PARTITION_RISCIX
 		case PARTITION_RISCIX_SCSI:
 			/* RISCiX - we don't know how to find the next one. */
 			slot = riscix_partition(state, first_sector, slot,
 						nr_sects);
 			break;
 #endif

 		case PARTITION_LINUX:
 			slot = linux_partition(state, first_sector, slot,
 					       nr_sects);
 			break;
 		}
 		put_dev_sector(sect);
 		if (slot == -1)
 			return -1;
 	} while (1);
 	put_dev_sector(sect);
 	return first ? 0 : 1;
 }
 #endif

 #ifdef CONFIG_ACORN_PARTITION_ADFS
 /*
  * Purpose: allocate ADFS partitions.
  *
  * Params : hd		- pointer to gendisk structure to store partition info.
  *	    dev		- device number to access.
  *
  * Returns: -1 on error, 0 for no ADFS boot sector, 1 for ok.
  *
  * Alloc  : hda  = whole drive
  *	    hda1 = ADFS partition on first drive.
  *	    hda2 = non-ADFS partition.
  */
 int adfspart_check_ADFS(struct parsed_partitions *state)
 {
 	unsigned long start_sect, nr_sects, sectscyl, heads;
 	Sector sect;
 	unsigned char *data;
 	struct adfs_discrecord *dr;
 	unsigned char id;
 	int slot = 1;

 	data = read_part_sector(state, 6, &sect);
 	if (!data)
 		return -1;

 	dr = adfs_partition(state, "ADFS", data, 0, slot++);
 	if (!dr) {
 		put_dev_sector(sect);
     		return 0;
 	}

 	heads = dr->heads + ((dr->lowsector >> 6) & 1);
 	sectscyl = dr->secspertrack * heads;
 	start_sect = ((data[0x1fe] << 8) + data[0x1fd]) * sectscyl;
 	id = data[0x1fc] & 15;
 	put_dev_sector(sect);

 	/*
 	 * Work out start of non-adfs partition.
 	 */
 	nr_sects = get_capacity(state->disk) - start_sect;

 	if (start_sect) {
 		switch (id) {
 #ifdef CONFIG_ACORN_PARTITION_RISCIX
 		case PARTITION_RISCIX_SCSI:
 		case PARTITION_RISCIX_MFM:
 			riscix_partition(state, start_sect, slot,
 						nr_sects);
 			break;
 #endif

 		case PARTITION_LINUX:
 			linux_partition(state, start_sect, slot,
 					       nr_sects);
 			break;
 		}
 	}
 	strlcat(state->pp_buf, "\n", PAGE_SIZE);
 	return 1;
 }
 #endif

 #ifdef CONFIG_ACORN_PARTITION_ICS

 struct ics_part {
 	__le32 start;
 	__le32 size;
 };

 static int adfspart_check_ICSLinux(struct parsed_partitions *state,
 				   unsigned long block)
 {
 	Sector sect;
 	unsigned char *data = read_part_sector(state, block, &sect);
 	int result = 0;

 	if (data) {
 		if (memcmp(data, "LinuxPart", 9) == 0)
 			result = 1;
 		put_dev_sector(sect);
 	}

 	return result;
 }

 /*
  * Check for a valid ICS partition using the checksum.
  */
 static inline int valid_ics_sector(const unsigned char *data)
 {
 	unsigned long sum;
 	int i;

 	for (i = 0, sum = 0x50617274; i < 508; i++)
 		sum += data[i];

 	sum -= le32_to_cpu(*(__le32 *)(&data[508]));

 	return sum == 0;
 }

 /*
  * Purpose: allocate ICS partitions.
  * Params : hd		- pointer to gendisk structure to store partition info.
  *	    dev		- device number to access.
  * Returns: -1 on error, 0 for no ICS table, 1 for partitions ok.
  * Alloc  : hda  = whole drive
  *	    hda1 = ADFS partition 0 on first drive.
  *	    hda2 = ADFS partition 1 on first drive.
  *		..etc..
  */
 int adfspart_check_ICS(struct parsed_partitions *state)
 {
 	const unsigned char *data;
 	const struct ics_part *p;
 	int slot;
 	Sector sect;

 	/*
 	 * Try ICS style partitions - sector 0 contains partition info.
 	 */
 	data = read_part_sector(state, 0, &sect);
 	if (!data)
 	    	return -1;

 	if (!valid_ics_sector(data)) {
 	    	put_dev_sector(sect);
 		return 0;
 	}

 	strlcat(state->pp_buf, " [ICS]", PAGE_SIZE);

 	for (slot = 1, p = (const struct ics_part *)data; p->size; p++) {
 		u32 start = le32_to_cpu(p->start);
 		s32 size = le32_to_cpu(p->size); /* yes, it's signed. */

 		if (slot == state->limit)
 			break;

 		/*
 		 * Negative sizes tell the RISC OS ICS driver to ignore
 		 * this partition - in effect it says that this does not
 		 * contain an ADFS filesystem.
 		 */
 		if (size < 0) {
 			size = -size;

 			/*
 			 * Our own extension - We use the first sector
 			 * of the partition to identify what type this
 			 * partition is.  We must not make this visible
 			 * to the filesystem.
 			 */
 			if (size > 1 && adfspart_check_ICSLinux(state, start)) {
 				start += 1;
 				size -= 1;
 			}
 		}

 		if (size)
 			put_partition(state, slot++, start, size);
 	}

 	put_dev_sector(sect);
 	strlcat(state->pp_buf, "\n", PAGE_SIZE);
 	return 1;
 }
 #endif

 #ifdef CONFIG_ACORN_PARTITION_POWERTEC
 struct ptec_part {
 	__le32 unused1;
 	__le32 unused2;
 	__le32 start;
 	__le32 size;
 	__le32 unused5;
 	char type[8];
 };

 static inline int valid_ptec_sector(const unsigned char *data)
 {
 	unsigned char checksum = 0x2a;
 	int i;

 	/*
 	 * If it looks like a PC/BIOS partition, then it
 	 * probably isn't PowerTec.
 	 */
 	if (data[510] == 0x55 && data[511] == 0xaa)
 		return 0;

 	for (i = 0; i < 511; i++)
 		checksum += data[i];

 	return checksum == data[511];
 }

 /*
  * Purpose: allocate ICS partitions.
  * Params : hd		- pointer to gendisk structure to store partition info.
  *	    dev		- device number to access.
  * Returns: -1 on error, 0 for no ICS table, 1 for partitions ok.
  * Alloc  : hda  = whole drive
  *	    hda1 = ADFS partition 0 on first drive.
  *	    hda2 = ADFS partition 1 on first drive.
  *		..etc..
  */
 int adfspart_check_POWERTEC(struct parsed_partitions *state)
 {
 	Sector sect;
 	const unsigned char *data;
 	const struct ptec_part *p;
 	int slot = 1;
 	int i;

 	data = read_part_sector(state, 0, &sect);
 	if (!data)
 		return -1;

 	if (!valid_ptec_sector(data)) {
 		put_dev_sector(sect);
 		return 0;
 	}

 	strlcat(state->pp_buf, " [POWERTEC]", PAGE_SIZE);

 	for (i = 0, p = (const struct ptec_part *)data; i < 12; i++, p++) {
 		u32 start = le32_to_cpu(p->start);
 		u32 size = le32_to_cpu(p->size);

 		if (size)
 			put_partition(state, slot++, start, size);
 	}

 	put_dev_sector(sect);
 	strlcat(state->pp_buf, "\n", PAGE_SIZE);
 	return 1;
 }
 #endif

 #ifdef CONFIG_ACORN_PARTITION_EESOX
 struct eesox_part {
 	char	magic[6];
 	char	name[10];
 	__le32	start;
 	__le32	unused6;
 	__le32	unused7;
 	__le32	unused8;
 };

 /*
  * Guess who created this format?
  */
 static const char eesox_name[] = {
 	'N', 'e', 'i', 'l', ' ',
 	'C', 'r', 'i', 't', 'c', 'h', 'e', 'l', 'l', ' ', ' '
 };

 /*
  * EESOX SCSI partition format.
  *
  * This is a goddamned awful partition format.  We don't seem to store
  * the size of the partition in this table, only the start addresses.
  *
  * There are two possibilities where the size comes from:
  *  1. The individual ADFS boot block entries that are placed on the disk.
  *  2. The start address of the next entry.
  */
 int adfspart_check_EESOX(struct parsed_partitions *state)
 {
 	Sector sect;
 	const unsigned char *data;
 	unsigned char buffer[256];
 	struct eesox_part *p;
 	sector_t start = 0;
 	int i, slot = 1;

 	data = read_part_sector(state, 7, &sect);
 	if (!data)
 		return -1;

 	/*
 	 * "Decrypt" the partition table.  God knows why...
 	 */
 	for (i = 0; i < 256; i++)
 		buffer[i] = data[i] ^ eesox_name[i & 15];

 	put_dev_sector(sect);

 	for (i = 0, p = (struct eesox_part *)buffer; i < 8; i++, p++) {
 		sector_t next;

 		if (memcmp(p->magic, "Eesox", 6))
 			break;

 		next = le32_to_cpu(p->start);
 		if (i)
 			put_partition(state, slot++, start, next - start);
 		start = next;
 	}

 	if (i != 0) {
 		sector_t size;

 		size = get_capacity(state->disk);
 		put_partition(state, slot++, start, size - start);
 		strlcat(state->pp_buf, "\n", PAGE_SIZE);
 	}

 	return i ? 1 : 0;
 }
 #endif
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Copyright (c) 1996-2000 Russell King.
	*
	* Scan ADFS partitions on hard disk drives. Unfortunately, there
	* isn't a standard for partitioning drives on Acorn machines, so
	* every single manufacturer of SCSI and IDE cards created their own
	* method.
	*/
	#include <linux/buffer_head.h>
	#include <linux/adfs_fs.h>

	#include "check.h"

	/*
	* Partition types. (Oh for reusability)
	*/
	#define PARTITION_RISCIX_MFM 1
	#define PARTITION_RISCIX_SCSI 2
	#define PARTITION_LINUX 9

	#if defined(CONFIG_ACORN_PARTITION_CUMANA) \|\| \
	defined(CONFIG_ACORN_PARTITION_ADFS)
	static struct adfs_discrecord *
	adfs_partition(struct parsed_partitions state, char name, char *data,
	unsigned long first_sector, int slot)
	{
	struct adfs_discrecord *dr;
	unsigned int nr_sects;

	if (adfs_checkbblk(data))
	return NULL;

	dr = (struct adfs_discrecord *)(data + 0x1c0);

	if (dr->disc_size == 0 && dr->disc_size_high == 0)
	return NULL;

	nr_sects = (le32_to_cpu(dr->disc_size_high) << 23) \|
	(le32_to_cpu(dr->disc_size) >> 9);

	if (name) {
	strlcat(state->pp_buf, " [", PAGE_SIZE);
	strlcat(state->pp_buf, name, PAGE_SIZE);
	strlcat(state->pp_buf, "]", PAGE_SIZE);
	}
	put_partition(state, slot, first_sector, nr_sects);
	return dr;
	}
	#endif

	#ifdef CONFIG_ACORN_PARTITION_RISCIX

	struct riscix_part {
	__le32 start;
	__le32 length;
	__le32 one;
	char name[16];
	};

	struct riscix_record {
	__le32 magic;
	#define RISCIX_MAGIC cpu_to_le32(0x4a657320)
	__le32 date;
	struct riscix_part part[8];
	};

	#if defined(CONFIG_ACORN_PARTITION_CUMANA) \|\| \
	defined(CONFIG_ACORN_PARTITION_ADFS)
	static int riscix_partition(struct parsed_partitions *state,
	unsigned long first_sect, int slot,
	unsigned long nr_sects)
	{
	Sector sect;
	struct riscix_record *rr;

	rr = read_part_sector(state, first_sect, &sect);
	if (!rr)
	return -1;

	strlcat(state->pp_buf, " [RISCiX]", PAGE_SIZE);


	if (rr->magic == RISCIX_MAGIC) {
	unsigned long size = nr_sects > 2 ? 2 : nr_sects;
	int part;

	strlcat(state->pp_buf, " <", PAGE_SIZE);

	put_partition(state, slot++, first_sect, size);
	for (part = 0; part < 8; part++) {
	if (rr->part[part].one &&
	memcmp(rr->part[part].name, "All\0", 4)) {
	put_partition(state, slot++,
	le32_to_cpu(rr->part[part].start),
	le32_to_cpu(rr->part[part].length));
	strlcat(state->pp_buf, "(", PAGE_SIZE);
	strlcat(state->pp_buf, rr->part[part].name, PAGE_SIZE);
	strlcat(state->pp_buf, ")", PAGE_SIZE);
	}
	}

	strlcat(state->pp_buf, " >\n", PAGE_SIZE);
	} else {
	put_partition(state, slot++, first_sect, nr_sects);
	}

	put_dev_sector(sect);
	return slot;
	}
	#endif
	#endif

	#define LINUX_NATIVE_MAGIC 0xdeafa1de
	#define LINUX_SWAP_MAGIC 0xdeafab1e

	struct linux_part {
	__le32 magic;
	__le32 start_sect;
	__le32 nr_sects;
	};

	#if defined(CONFIG_ACORN_PARTITION_CUMANA) \|\| \
	defined(CONFIG_ACORN_PARTITION_ADFS)
	static int linux_partition(struct parsed_partitions *state,
	unsigned long first_sect, int slot,
	unsigned long nr_sects)
	{
	Sector sect;
	struct linux_part *linuxp;
	unsigned long size = nr_sects > 2 ? 2 : nr_sects;

	strlcat(state->pp_buf, " [Linux]", PAGE_SIZE);

	put_partition(state, slot++, first_sect, size);

	linuxp = read_part_sector(state, first_sect, &sect);
	if (!linuxp)
	return -1;

	strlcat(state->pp_buf, " <", PAGE_SIZE);
	while (linuxp->magic == cpu_to_le32(LINUX_NATIVE_MAGIC) \|\|
	linuxp->magic == cpu_to_le32(LINUX_SWAP_MAGIC)) {
	if (slot == state->limit)
	break;
	put_partition(state, slot++, first_sect +
	le32_to_cpu(linuxp->start_sect),
	le32_to_cpu(linuxp->nr_sects));
	linuxp ++;
	}
	strlcat(state->pp_buf, " >", PAGE_SIZE);

	put_dev_sector(sect);
	return slot;
	}
	#endif

	#ifdef CONFIG_ACORN_PARTITION_CUMANA
	int adfspart_check_CUMANA(struct parsed_partitions *state)
	{
	unsigned long first_sector = 0;
	unsigned int start_blk = 0;
	Sector sect;
	unsigned char *data;
	char *name = "CUMANA/ADFS";
	int first = 1;
	int slot = 1;

	/*
	* Try Cumana style partitions - sector 6 contains ADFS boot block
	* with pointer to next 'drive'.
	*
	* There are unknowns in this code - is the 'cylinder number' of the
	* next partition relative to the start of this one - I'm assuming
	* it is.
	*
	* Also, which ID did Cumana use?
	*
	* This is totally unfinished, and will require more work to get it
	* going. Hence it is totally untested.
	*/
	do {
	struct adfs_discrecord *dr;
	unsigned int nr_sects;

	data = read_part_sector(state, start_blk * 2 + 6, &sect);
	if (!data)
	return -1;

	if (slot == state->limit)
	break;

	dr = adfs_partition(state, name, data, first_sector, slot++);
	if (!dr)
	break;

	name = NULL;

	nr_sects = (data[0x1fd] + (data[0x1fe] << 8)) *
	(dr->heads + (dr->lowsector & 0x40 ? 1 : 0)) *
	dr->secspertrack;

	if (!nr_sects)
	break;

	first = 0;
	first_sector += nr_sects;
	start_blk += nr_sects >> (BLOCK_SIZE_BITS - 9);
	nr_sects = 0; /* hmm - should be partition size */

	switch (data[0x1fc] & 15) {
	case 0: /* No partition / ADFS? */
	break;

	#ifdef CONFIG_ACORN_PARTITION_RISCIX
	case PARTITION_RISCIX_SCSI:
	/* RISCiX - we don't know how to find the next one. */
	slot = riscix_partition(state, first_sector, slot,
	nr_sects);
	break;
	#endif

	case PARTITION_LINUX:
	slot = linux_partition(state, first_sector, slot,
	nr_sects);
	break;
	}
	put_dev_sector(sect);
	if (slot == -1)
	return -1;
	} while (1);
	put_dev_sector(sect);
	return first ? 0 : 1;
	}
	#endif

	#ifdef CONFIG_ACORN_PARTITION_ADFS
	/*
	* Purpose: allocate ADFS partitions.
	*
	* Params : hd - pointer to gendisk structure to store partition info.
	* dev - device number to access.
	*
	* Returns: -1 on error, 0 for no ADFS boot sector, 1 for ok.
	*
	* Alloc : hda = whole drive
	* hda1 = ADFS partition on first drive.
	* hda2 = non-ADFS partition.
	*/
	int adfspart_check_ADFS(struct parsed_partitions *state)
	{
	unsigned long start_sect, nr_sects, sectscyl, heads;
	Sector sect;
	unsigned char *data;
	struct adfs_discrecord *dr;
	unsigned char id;
	int slot = 1;

	data = read_part_sector(state, 6, &sect);
	if (!data)
	return -1;

	dr = adfs_partition(state, "ADFS", data, 0, slot++);
	if (!dr) {
	put_dev_sector(sect);
	return 0;
	}

	heads = dr->heads + ((dr->lowsector >> 6) & 1);
	sectscyl = dr->secspertrack * heads;
	start_sect = ((data[0x1fe] << 8) + data[0x1fd]) * sectscyl;
	id = data[0x1fc] & 15;
	put_dev_sector(sect);

	/*
	* Work out start of non-adfs partition.
	*/
	nr_sects = get_capacity(state->disk) - start_sect;

	if (start_sect) {
	switch (id) {
	#ifdef CONFIG_ACORN_PARTITION_RISCIX
	case PARTITION_RISCIX_SCSI:
	case PARTITION_RISCIX_MFM:
	riscix_partition(state, start_sect, slot,
	nr_sects);
	break;
	#endif

	case PARTITION_LINUX:
	linux_partition(state, start_sect, slot,
	nr_sects);
	break;
	}
	}
	strlcat(state->pp_buf, "\n", PAGE_SIZE);
	return 1;
	}
	#endif

	#ifdef CONFIG_ACORN_PARTITION_ICS

	struct ics_part {
	__le32 start;
	__le32 size;
	};

	static int adfspart_check_ICSLinux(struct parsed_partitions *state,
	unsigned long block)
	{
	Sector sect;
	unsigned char *data = read_part_sector(state, block, &sect);
	int result = 0;

	if (data) {
	if (memcmp(data, "LinuxPart", 9) == 0)
	result = 1;
	put_dev_sector(sect);
	}

	return result;
	}

	/*
	* Check for a valid ICS partition using the checksum.
	*/
	static inline int valid_ics_sector(const unsigned char *data)
	{
	unsigned long sum;
	int i;

	for (i = 0, sum = 0x50617274; i < 508; i++)
	sum += data[i];

	sum -= le32_to_cpu((__le32 )(&data[508]));

	return sum == 0;
	}

	/*
	* Purpose: allocate ICS partitions.
	* Params : hd - pointer to gendisk structure to store partition info.
	* dev - device number to access.
	* Returns: -1 on error, 0 for no ICS table, 1 for partitions ok.
	* Alloc : hda = whole drive
	* hda1 = ADFS partition 0 on first drive.
	* hda2 = ADFS partition 1 on first drive.
	* ..etc..
	*/
	int adfspart_check_ICS(struct parsed_partitions *state)
	{
	const unsigned char *data;
	const struct ics_part *p;
	int slot;
	Sector sect;

	/*
	* Try ICS style partitions - sector 0 contains partition info.
	*/
	data = read_part_sector(state, 0, &sect);
	if (!data)
	return -1;

	if (!valid_ics_sector(data)) {
	put_dev_sector(sect);
	return 0;
	}

	strlcat(state->pp_buf, " [ICS]", PAGE_SIZE);

	for (slot = 1, p = (const struct ics_part *)data; p->size; p++) {
	u32 start = le32_to_cpu(p->start);
	s32 size = le32_to_cpu(p->size); /* yes, it's signed. */

	if (slot == state->limit)
	break;

	/*
	* Negative sizes tell the RISC OS ICS driver to ignore
	* this partition - in effect it says that this does not
	* contain an ADFS filesystem.
	*/
	if (size < 0) {
	size = -size;

	/*
	* Our own extension - We use the first sector
	* of the partition to identify what type this
	* partition is. We must not make this visible
	* to the filesystem.
	*/
	if (size > 1 && adfspart_check_ICSLinux(state, start)) {
	start += 1;
	size -= 1;
	}
	}

	if (size)
	put_partition(state, slot++, start, size);
	}

	put_dev_sector(sect);
	strlcat(state->pp_buf, "\n", PAGE_SIZE);
	return 1;
	}
	#endif

	#ifdef CONFIG_ACORN_PARTITION_POWERTEC
	struct ptec_part {
	__le32 unused1;
	__le32 unused2;
	__le32 start;
	__le32 size;
	__le32 unused5;
	char type[8];
	};

	static inline int valid_ptec_sector(const unsigned char *data)
	{
	unsigned char checksum = 0x2a;
	int i;

	/*
	* If it looks like a PC/BIOS partition, then it
	* probably isn't PowerTec.
	*/
	if (data[510] == 0x55 && data[511] == 0xaa)
	return 0;

	for (i = 0; i < 511; i++)
	checksum += data[i];

	return checksum == data[511];
	}

	/*
	* Purpose: allocate ICS partitions.
	* Params : hd - pointer to gendisk structure to store partition info.
	* dev - device number to access.
	* Returns: -1 on error, 0 for no ICS table, 1 for partitions ok.
	* Alloc : hda = whole drive
	* hda1 = ADFS partition 0 on first drive.
	* hda2 = ADFS partition 1 on first drive.
	* ..etc..
	*/
	int adfspart_check_POWERTEC(struct parsed_partitions *state)
	{
	Sector sect;
	const unsigned char *data;
	const struct ptec_part *p;
	int slot = 1;
	int i;

	data = read_part_sector(state, 0, &sect);
	if (!data)
	return -1;

	if (!valid_ptec_sector(data)) {
	put_dev_sector(sect);
	return 0;
	}

	strlcat(state->pp_buf, " [POWERTEC]", PAGE_SIZE);

	for (i = 0, p = (const struct ptec_part *)data; i < 12; i++, p++) {
	u32 start = le32_to_cpu(p->start);
	u32 size = le32_to_cpu(p->size);

	if (size)
	put_partition(state, slot++, start, size);
	}

	put_dev_sector(sect);
	strlcat(state->pp_buf, "\n", PAGE_SIZE);
	return 1;
	}
	#endif

	#ifdef CONFIG_ACORN_PARTITION_EESOX
	struct eesox_part {
	char magic[6];
	char name[10];
	__le32 start;
	__le32 unused6;
	__le32 unused7;
	__le32 unused8;
	};

	/*
	* Guess who created this format?
	*/
	static const char eesox_name[] = {
	'N', 'e', 'i', 'l', ' ',
	'C', 'r', 'i', 't', 'c', 'h', 'e', 'l', 'l', ' ', ' '
	};

	/*
	* EESOX SCSI partition format.
	*
	* This is a goddamned awful partition format. We don't seem to store
	* the size of the partition in this table, only the start addresses.
	*
	* There are two possibilities where the size comes from:
	* 1. The individual ADFS boot block entries that are placed on the disk.
	* 2. The start address of the next entry.
	*/
	int adfspart_check_EESOX(struct parsed_partitions *state)
	{
	Sector sect;
	const unsigned char *data;
	unsigned char buffer[256];
	struct eesox_part *p;
	sector_t start = 0;
	int i, slot = 1;

	data = read_part_sector(state, 7, &sect);
	if (!data)
	return -1;

	/*
	* "Decrypt" the partition table. God knows why...
	*/
	for (i = 0; i < 256; i++)
	buffer[i] = data[i] ^ eesox_name[i & 15];

	put_dev_sector(sect);

	for (i = 0, p = (struct eesox_part *)buffer; i < 8; i++, p++) {
	sector_t next;

	if (memcmp(p->magic, "Eesox", 6))
	break;

	next = le32_to_cpu(p->start);
	if (i)
	put_partition(state, slot++, start, next - start);
	start = next;
	}

	if (i != 0) {
	sector_t size;

	size = get_capacity(state->disk);
	put_partition(state, slot++, start, size - start);
	strlcat(state->pp_buf, "\n", PAGE_SIZE);
	}

	return i ? 1 : 0;
	}
	#endif