i386/linux/linux-2.3.21/fs/partitions/amiga.c

   1 /*
   2  *  fs/partitions/amiga.c
   3  *
   4  *  Code extracted from drivers/block/genhd.c
   5  *
   6  *  Copyright (C) 1991-1998  Linus Torvalds
   7  *  Re-organised Feb 1998 Russell King
   8  */
   9
  10 #include <linux/fs.h>
  11 #include <linux/genhd.h>
  12 #include <linux/kernel.h>
  13 #include <linux/major.h>
  14 #include <linux/string.h>
  15 #include <linux/blk.h>
  16
  17 #include <asm/byteorder.h>
  18 #include <linux/affs_hardblocks.h>
  19
  20 #include "check.h"
  21 #include "amiga.h"
  22
  23 static __inline__ u32
  24 checksum_block(u32 *m, int size)
  25 {
  26         u32 sum = 0;
  27
  28         while (size--)
  29                 sum += be32_to_cpu(*m++);
  30         return sum;
  31 }
  32
  33 int
  34 amiga_partition(struct gendisk *hd, kdev_t dev, unsigned long first_sector, int first_part_minor)
  35 {
  36         struct buffer_head      *bh;
  37         struct RigidDiskBlock   *rdb;
  38         struct PartitionBlock   *pb;
  39         int                      start_sect;
  40         int                      nr_sects;
  41         int                      blk;
  42         int                      part, res;
  43         int                      old_blocksize;
  44         int                      blocksize;
  45
  46         old_blocksize = get_ptable_blocksize(dev);
  47         blocksize = get_hardsect_size(dev);
  48
  49         if (blocksize < 512)
  50                 blocksize = 512;
  51
  52         set_blocksize(dev,blocksize);
  53         res = 0;
  54
  55         for (blk = 0; blk < RDB_ALLOCATION_LIMIT; blk++) {
  56                 if(!(bh = bread(dev,blk,blocksize))) {
  57                         printk("Dev %s: unable to read RDB block %d\n",
  58                                kdevname(dev),blk);
  59                         goto rdb_done;
  60                 }
  61                 if (*(u32 *)bh->b_data == cpu_to_be32(IDNAME_RIGIDDISK)) {
  62                         rdb = (struct RigidDiskBlock *)bh->b_data;
  63                         if (checksum_block((u32 *)bh->b_data,be32_to_cpu(rdb->rdb_SummedLongs) & 0x7F)) {
  64                                 /* Try again with 0xdc..0xdf zeroed, Windows might have
  65                                  * trashed it.
  66                                  */
  67                                 *(u32 *)(&bh->b_data[0xdc]) = 0;
  68                                 if (checksum_block((u32 *)bh->b_data,
  69                                                 be32_to_cpu(rdb->rdb_SummedLongs) & 0x7F)) {
  70                                         brelse(bh);
  71                                         printk("Dev %s: RDB in block %d has bad checksum\n",
  72                                                kdevname(dev),blk);
  73                                         continue;
  74                                 }
  75                                 printk("Warning: Trashed word at 0xd0 in block %d "
  76                                         "ignored in checksum calculation\n",blk);
  77                         }
  78                         printk(" RDSK");
  79                         blk = be32_to_cpu(rdb->rdb_PartitionList);
  80                         brelse(bh);
  81                         for (part = 1; blk > 0 && part <= 16; part++) {
  82                                 if (!(bh = bread(dev,blk,blocksize))) {
  83                                         printk("Dev %s: unable to read partition block %d\n",
  84                                                        kdevname(dev),blk);
  85                                         goto rdb_done;
  86                                 }
  87                                 pb  = (struct PartitionBlock *)bh->b_data;
  88                                 blk = be32_to_cpu(pb->pb_Next);
  89                                 if (pb->pb_ID == cpu_to_be32(IDNAME_PARTITION) && checksum_block(
  90                                     (u32 *)pb,be32_to_cpu(pb->pb_SummedLongs) & 0x7F) == 0 ) {
  91
  92                                         /* Tell Kernel about it */
  93
  94                                         if (!(nr_sects = (be32_to_cpu(pb->pb_Environment[10]) + 1 -
  95                                                           be32_to_cpu(pb->pb_Environment[9])) *
  96                                                          be32_to_cpu(pb->pb_Environment[3]) *
  97                                                          be32_to_cpu(pb->pb_Environment[5]))) {
  98                                                 brelse(bh);
  99                                                 continue;
 100                                         }
 101                                         start_sect = be32_to_cpu(pb->pb_Environment[9]) *
 102                                                      be32_to_cpu(pb->pb_Environment[3]) *
 103                                                      be32_to_cpu(pb->pb_Environment[5]);
 104                                         add_gd_partition(hd,first_part_minor,start_sect,nr_sects);
 105                                         first_part_minor++;
 106                                         res = 1;
 107                                 }
 108                                 brelse(bh);
 109                         }
 110                         printk("\n");
 111                         break;
 112                 }
 113                 else
 114                         brelse(bh);
 115         }
 116
 117 rdb_done:
 118         set_blocksize(dev,old_blocksize);
 119         return res;
 120 }