fs/partitions/sun.c

   1 /*
   2  *  fs/partitions/sun.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/system.h>
  18
  19 #include "check.h"
  20 #include "sun.h"
  21
  22 int sun_partition(struct gendisk *hd, kdev_t dev, unsigned long first_sector, int first_part_minor)
  23 {
  24         int i, csum;
  25         unsigned short *ush;
  26         struct buffer_head *bh;
  27         struct sun_disklabel {
  28                 unsigned char info[128];   /* Informative text string */
  29                 unsigned char spare[292];  /* Boot information etc. */
  30                 unsigned short rspeed;     /* Disk rotational speed */
  31                 unsigned short pcylcount;  /* Physical cylinder count */
  32                 unsigned short sparecyl;   /* extra sects per cylinder */
  33                 unsigned char spare2[4];   /* More magic... */
  34                 unsigned short ilfact;     /* Interleave factor */
  35                 unsigned short ncyl;       /* Data cylinder count */
  36                 unsigned short nacyl;      /* Alt. cylinder count */
  37                 unsigned short ntrks;      /* Tracks per cylinder */
  38                 unsigned short nsect;      /* Sectors per track */
  39                 unsigned char spare3[4];   /* Even more magic... */
  40                 struct sun_partition {
  41                         __u32 start_cylinder;
  42                         __u32 num_sectors;
  43                 } partitions[8];
  44                 unsigned short magic;      /* Magic number */
  45                 unsigned short csum;       /* Label xor'd checksum */
  46         } * label;
  47         struct sun_partition *p;
  48         unsigned long spc;
  49
  50         if(!(bh = bread(dev, 0, get_ptable_blocksize(dev)))) {
  51                 printk(KERN_WARNING "Dev %s: unable to read partition table\n",
  52                        kdevname(dev));
  53                 return -1;
  54         }
  55         label = (struct sun_disklabel *) bh->b_data;
  56         p = label->partitions;
  57         if (be16_to_cpu(label->magic) != SUN_LABEL_MAGIC) {
  58 /*              printk(KERN_INFO "Dev %s Sun disklabel: bad magic %04x\n",
  59                        kdevname(dev), be16_to_cpu(label->magic)); */
  60                 brelse(bh);
  61                 return 0;
  62         }
  63         /* Look at the checksum */
  64         ush = ((unsigned short *) (label+1)) - 1;
  65         for(csum = 0; ush >= ((unsigned short *) label);)
  66                 csum ^= *ush--;
  67         if(csum) {
  68                 printk("Dev %s Sun disklabel: Csum bad, label corrupted\n",
  69                        kdevname(dev));
  70                 brelse(bh);
  71                 return 0;
  72         }
  73         /* All Sun disks have 8 partition entries */
  74         spc = be16_to_cpu(label->ntrks) * be16_to_cpu(label->nsect);
  75         for(i=0; i < 8; i++, p++) {
  76                 unsigned long st_sector;
  77                 int num_sectors;
  78
  79                 st_sector = first_sector + be32_to_cpu(p->start_cylinder) * spc;
  80                 num_sectors = be32_to_cpu(p->num_sectors);
  81                 if (num_sectors)
  82                         add_gd_partition(hd, first_part_minor, st_sector, num_sectors);
  83                 first_part_minor++;
  84         }
  85         printk("\n");
  86         brelse(bh);
  87         return 1;
  88 }
  89