/*
   *  linux/fs/partitions/acorn.c
   *
   *  Copyright (c) 1996-2000 Russell King.
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   *
   *  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"
  #include "acorn.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, " >
  ", 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 = (state->bdev->bd_inode->i_size >> 9) - start_sect;

  
  	if (start_sect) {
  		switch (id) {
  #ifdef CONFIG_ACORN_PARTITION_RISCIX
  		case PARTITION_RISCIX_SCSI:
  		case PARTITION_RISCIX_MFM:

  			slot = riscix_partition(state, start_sect, slot,
  						nr_sects);

  			break;
  #endif
  
  		case PARTITION_LINUX:

  			slot = linux_partition(state, start_sect, slot,
  					       nr_sects);

  			break;
  		}
  	}

  	strlcat(state->pp_buf, "
  ", 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, "
  ", 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, "
  ", 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->bdev->bd_disk);

  		put_partition(state, slot++, start, size - start);

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

  	}
  
  	return i ? 1 : 0;
  }
  #endif