root/fs/partitions/amiga.c

DEFINITIONS

1. checksum_block
2. amiga_partition

/*
 *  fs/partitions/amiga.c
 *
 *  Code extracted from drivers/block/genhd.c
 *
 *  Copyright (C) 1991-1998  Linus Torvalds
 *  Re-organised Feb 1998 Russell King
 */

#include <linux/types.h>
#include <linux/affs_hardblocks.h>

#include "check.h"
#include "amiga.h"

static __inline__ u32
checksum_block(__be32 *m, int size)
{
        u32 sum = 0;

        while (size--)
                sum += be32_to_cpu(*m++);
        return sum;
}

int
amiga_partition(struct parsed_partitions *state, struct block_device *bdev)
{
        Sector sect;
        unsigned char *data;
        struct RigidDiskBlock *rdb;
        struct PartitionBlock *pb;
        int start_sect, nr_sects, blk, part, res = 0;
        int blksize = 1;        /* Multiplier for disk block size */
        int slot = 1;
        char b[BDEVNAME_SIZE];

        for (blk = 0; ; blk++, put_dev_sector(sect)) {
                if (blk == RDB_ALLOCATION_LIMIT)
                        goto rdb_done;
                data = read_dev_sector(bdev, blk, &sect);
                if (!data) {
                        if (warn_no_part)
                                printk("Dev %s: unable to read RDB block %d\n",
                                       bdevname(bdev, b), blk);
                        res = -1;
                        goto rdb_done;
                }
                if (*(__be32 *)data != cpu_to_be32(IDNAME_RIGIDDISK))
                        continue;

                rdb = (struct RigidDiskBlock *)data;
                if (checksum_block((__be32 *)data, be32_to_cpu(rdb->rdb_SummedLongs) & 0x7F) == 0)
                        break;
                /* Try again with 0xdc..0xdf zeroed, Windows might have
                 * trashed it.
                 */
                *(__be32 *)(data+0xdc) = 0;
                if (checksum_block((__be32 *)data,
                                be32_to_cpu(rdb->rdb_SummedLongs) & 0x7F)==0) {
                        printk("Warning: Trashed word at 0xd0 in block %d "
                                "ignored in checksum calculation\n",blk);
                        break;
                }

                printk("Dev %s: RDB in block %d has bad checksum\n",
                               bdevname(bdev, b), blk);
        }

        /* blksize is blocks per 512 byte standard block */
        blksize = be32_to_cpu( rdb->rdb_BlockBytes ) / 512;

        printk(" RDSK (%d)", blksize * 512);    /* Be more informative */
        blk = be32_to_cpu(rdb->rdb_PartitionList);
        put_dev_sector(sect);
        for (part = 1; blk>0 && part<=16; part++, put_dev_sector(sect)) {
                blk *= blksize; /* Read in terms partition table understands */
                data = read_dev_sector(bdev, blk, &sect);
                if (!data) {
                        if (warn_no_part)
                                printk("Dev %s: unable to read partition block %d\n",
                                       bdevname(bdev, b), blk);
                        res = -1;
                        goto rdb_done;
                }
                pb  = (struct PartitionBlock *)data;
                blk = be32_to_cpu(pb->pb_Next);
                if (pb->pb_ID != cpu_to_be32(IDNAME_PARTITION))
                        continue;
                if (checksum_block((__be32 *)pb, be32_to_cpu(pb->pb_SummedLongs) & 0x7F) != 0 )
                        continue;

                /* Tell Kernel about it */

                nr_sects = (be32_to_cpu(pb->pb_Environment[10]) + 1 -
                            be32_to_cpu(pb->pb_Environment[9])) *
                           be32_to_cpu(pb->pb_Environment[3]) *
                           be32_to_cpu(pb->pb_Environment[5]) *
                           blksize;
                if (!nr_sects)
                        continue;
                start_sect = be32_to_cpu(pb->pb_Environment[9]) *
                             be32_to_cpu(pb->pb_Environment[3]) *
                             be32_to_cpu(pb->pb_Environment[5]) *
                             blksize;
                put_partition(state,slot++,start_sect,nr_sects);
                {
                        /* Be even more informative to aid mounting */
                        char dostype[4];
                        __be32 *dt = (__be32 *)dostype;
                        *dt = pb->pb_Environment[16];
                        if (dostype[3] < ' ')
                                printk(" (%c%c%c^%c)",
                                        dostype[0], dostype[1],
                                        dostype[2], dostype[3] + '@' );
                        else
                                printk(" (%c%c%c%c)",
                                        dostype[0], dostype[1],
                                        dostype[2], dostype[3]);
                        printk("(res %d spb %d)",
                                be32_to_cpu(pb->pb_Environment[6]),
                                be32_to_cpu(pb->pb_Environment[4]));
                }
                res = 1;
        }
        printk("\n");

rdb_done:
        return res;
}