/*
 *  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.
 */
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/kdev_t.h>
#include <linux/major.h>
#include <linux/string.h>
#include <linux/genhd.h>
#include <linux/fs.h>
#include <linux/pagemap.h>

#include "check.h"
#include "acorn.h"

static void
adfspart_setgeometry(kdev_t dev, unsigned int secspertrack, unsigned int heads)
{
#ifdef CONFIG_BLK_DEV_MFM
        extern void xd_set_geometry(kdev_t dev, unsigned char, unsigned char,
                                    unsigned long, unsigned int);

        if (MAJOR(dev) == MFM_ACORN_MAJOR) {
                unsigned long totalblocks = hd->part[MINOR(dev)].nr_sects;
                xd_set_geometry(dev, secspertrack, heads, totalblocks, 1);
        }
#endif
}

static struct adfs_discrecord *
adfs_partition(struct gendisk *hd, char *name, char *data,
               unsigned long first_sector, int minor)
{
        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)
                printk(" [%s]", name);
        add_gd_partition(hd, minor, first_sector, nr_sects);
        return dr;
}

#ifdef CONFIG_ACORN_PARTITION_RISCIX
static int
riscix_partition(struct gendisk *hd, struct block_device *bdev,
                unsigned long first_sect, int minor, unsigned long nr_sects)
{
        Sector sect;
        struct riscix_record *rr;
        
        rr = (struct riscix_record *)read_dev_sector(bdev, first_sect, &sect);
        if (!rr)
                return -1;

        printk(" [RISCiX]");


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

                printk(" <");

                add_gd_partition(hd, minor++, first_sect, size);
                for (part = 0; part < 8; part++) {
                        if (rr->part[part].one &&
                            memcmp(rr->part[part].name, "All\0", 4)) {
                                add_gd_partition(hd, minor++,
                                                le32_to_cpu(rr->part[part].start),
                                                le32_to_cpu(rr->part[part].length));
                                printk("(%s)", rr->part[part].name);
                        }
                }

                printk(" >\n");
        } else {
                add_gd_partition(hd, minor++, first_sect, nr_sects);
        }

        put_dev_sector(sect);
        return minor;
}
#endif

static int
linux_partition(struct gendisk *hd, struct block_device *bdev,
                unsigned long first_sect, int minor, unsigned long nr_sects)
{
        Sector sect;
        struct linux_part *linuxp;
        unsigned int mask = (1 << hd->minor_shift) - 1;
        unsigned long size = nr_sects > 2 ? 2 : nr_sects;

        printk(" [Linux]");

        add_gd_partition(hd, minor++, first_sect, size);

        linuxp = (struct linux_part *)read_dev_sector(bdev, first_sect, &sect);
        if (!linuxp)
                return -1;

        printk(" <");
        while (linuxp->magic == cpu_to_le32(LINUX_NATIVE_MAGIC) ||
               linuxp->magic == cpu_to_le32(LINUX_SWAP_MAGIC)) {
                if (!(minor & mask))
                        break;
                add_gd_partition(hd, minor++, first_sect +
                                 le32_to_cpu(linuxp->start_sect),
                                 le32_to_cpu(linuxp->nr_sects));
                linuxp ++;
        }
        printk(" >");

        put_dev_sector(sect);
        return minor;
}

#ifdef CONFIG_ACORN_PARTITION_CUMANA
static int
adfspart_check_CUMANA(struct gendisk *hd, struct block_device *bdev,
                      unsigned long first_sector, int minor)
{
        unsigned int start_blk = 0, mask = (1 << hd->minor_shift) - 1;
        Sector sect;
        unsigned char *data;
        char *name = "CUMANA/ADFS";
        int first = 1;

        /*
         * Try Cumana style partitions - sector 3 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;

                if (!(minor & mask))
                        break;

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

                dr = adfs_partition(hd, name, data, first_sector, minor++);
                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. */
                        minor = riscix_partition(hd, bdev, first_sector,
                                                 minor, nr_sects);
                        break;
#endif

                case PARTITION_LINUX:
                        minor = linux_partition(hd, bdev, first_sector,
                                                minor, nr_sects);
                        break;
                }
                put_dev_sector(sect);
                if (minor == -1)
                        return minor;
        } 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.
 *          first_sector- first readable sector on the device.
 *          minor       - first available minor on device.
 *
 * 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.
 */
static int
adfspart_check_ADFS(struct gendisk *hd, struct block_device *bdev,
                   unsigned long first_sector, int minor)
{
        unsigned long start_sect, nr_sects, sectscyl, heads;
        Sector sect;
        unsigned char *data;
        struct adfs_discrecord *dr;
        unsigned char id;

        data = read_dev_sector(bdev, 6, &sect);
        if (!data)
                return -1;

        dr = adfs_partition(hd, "ADFS", data, first_sector, minor++);
        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);

        adfspart_setgeometry(to_kdev_t(bdev->bd_dev), dr->secspertrack, heads);
        invalidate_bdev(bdev, 1);
        truncate_inode_pages(bdev->bd_inode->i_mapping, 0);

        /*
         * Work out start of non-adfs partition.
         */
        nr_sects = hd->part[MINOR(to_kdev_t(bdev->bd_dev))].nr_sects - start_sect;

        if (start_sect) {
                first_sector += start_sect;

                switch (id) {
#ifdef CONFIG_ACORN_PARTITION_RISCIX
                case PARTITION_RISCIX_SCSI:
                case PARTITION_RISCIX_MFM:
                        minor = riscix_partition(hd, bdev, first_sector,
                                                 minor, nr_sects);
                        break;
#endif

                case PARTITION_LINUX:
                        minor = linux_partition(hd, bdev, first_sector,
                                                minor, nr_sects);
                        break;
                }
        }
        return 1;
}
#endif

#ifdef CONFIG_ACORN_PARTITION_ICS
static int adfspart_check_ICSLinux(struct block_device *bdev, unsigned long block)
{
        Sector sect;
        unsigned char *data = read_dev_sector(bdev, block, &sect);
        int result = 0;

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

        return result;
}

/*
 * Purpose: allocate ICS partitions.
 * Params : hd          - pointer to gendisk structure to store partition info.
 *          dev         - device number to access.
 *          first_sector- first readable sector on the device.
 *          minor       - first available minor on device.
 * 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..
 */
static int
adfspart_check_ICS(struct gendisk *hd, struct block_device *bdev,
                   unsigned long first_sector, int minor)
{
        Sector sect;
        unsigned char *data;
        unsigned long sum;
        unsigned int i, mask = (1 << hd->minor_shift) - 1;
        struct ics_part *p;

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

        /*
         * check for a valid checksum
         */
        for (i = 0, sum = 0x50617274; i < 508; i++)
                sum += data[i];

        sum -= le32_to_cpu(*(__u32 *)(&data[508]));
        if (sum) {
                put_dev_sector(sect);
                return 0; /* not ICS partition table */
        }

        printk(" [ICS]");

        for (p = (struct ics_part *)data; p->size; p++) {
                unsigned long start;
                long size;

                if ((minor & mask) == 0)
                        break;

                start = le32_to_cpu(p->start);
                size  = le32_to_cpu(p->size);

                if (size < 0) {
                        size = -size;

                        /*
                         * We use the first sector to identify what type
                         * this partition is...
                         */
                        if (size > 1 && adfspart_check_ICSLinux(bdev, start)) {
                                start += 1;
                                size -= 1;
                        }
                }

                if (size) {
                        add_gd_partition(hd, minor, first_sector + start, size);
                        minor++;
                }
        }

        put_dev_sector(sect);
        return 1;
}
#endif

/*
 * Purpose: allocate ICS partitions.
 * Params : hd          - pointer to gendisk structure to store partition info.
 *          dev         - device number to access.
 *          first_sector- first readable sector on the device.
 *          minor       - first available minor on device.
 * 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..
 */
#ifdef CONFIG_ACORN_PARTITION_POWERTEC
static int
adfspart_check_POWERTEC(struct gendisk *hd, struct block_device *bdev,
                        unsigned long first_sector, int minor)
{
        Sector sect;
        unsigned char *data;
        struct ptec_partition *p;
        unsigned char checksum;
        int i;

        data = read_dev_sector(bdev, 0, &sect);
        if (!data)
                return -1;

        for (checksum = 0x2a, i = 0; i < 511; i++)
                checksum += data[i];

        if (checksum != data[511]) {
                put_dev_sector(sect);
                return 0;
        }

        printk(" [POWERTEC]");

        for (i = 0, p = (struct ptec_partition *)data; i < 12; i++, p++) {
                unsigned long start;
                unsigned long size;

                start = le32_to_cpu(p->start);
                size  = le32_to_cpu(p->size);

                if (size)
                        add_gd_partition(hd, minor, first_sector + start,
                                         size);
                minor++;
        }

        put_dev_sector(sect);
        return 1;
}
#endif

static int (*partfn[])(struct gendisk *, struct block_device *, unsigned long, int) = {
#ifdef CONFIG_ACORN_PARTITION_ICS
        adfspart_check_ICS,
#endif
#ifdef CONFIG_ACORN_PARTITION_POWERTEC
        adfspart_check_POWERTEC,
#endif
#ifdef CONFIG_ACORN_PARTITION_CUMANA
        adfspart_check_CUMANA,
#endif
#ifdef CONFIG_ACORN_PARTITION_ADFS
        adfspart_check_ADFS,
#endif
        NULL
};
/*
 * Purpose: initialise all the partitions on an ADFS drive.
 *          These may be other ADFS partitions or a Linux/RiscBSD/RISCiX
 *          partition.
 *
 * Params : hd          - pointer to gendisk structure
 *          dev         - device number to access
 *          first_sect  - first available sector on the disk.
 *          first_minor - first available minor on this device.
 *
 * Returns: -1 on error, 0 if not ADFS format, 1 if ok.
 */
int acorn_partition(struct gendisk *hd, struct block_device *bdev,
                    unsigned long first_sect, int first_minor)
{
        int i;

        for (i = 0; partfn[i]; i++) {
                int r = partfn[i](hd, bdev, first_sect, first_minor);
                if (r) {
                        if (r > 0)
                                printk("\n");
                        return r;
                }
        }
        return 0;
}