include/linux/adfs_fs.h

   1 #ifndef _ADFS_FS_H
   2 #define _ADFS_FS_H
   3
   4 #include <linux/types.h>
   5 #include <linux/magic.h>
   6
   7 /*
   8  * Disc Record at disc address 0xc00
   9  */
  10 struct adfs_discrecord {
  11     __u8  log2secsize;
  12     __u8  secspertrack;
  13     __u8  heads;
  14     __u8  density;
  15     __u8  idlen;
  16     __u8  log2bpmb;
  17     __u8  skew;
  18     __u8  bootoption;
  19     __u8  lowsector;
  20     __u8  nzones;
  21     __le16 zone_spare;
  22     __le32 root;
  23     __le32 disc_size;
  24     __le16 disc_id;
  25     __u8  disc_name[10];
  26     __le32 disc_type;
  27     __le32 disc_size_high;
  28     __u8  log2sharesize:4;
  29     __u8  unused40:4;
  30     __u8  big_flag:1;
  31     __u8  unused41:1;
  32     __u8  nzones_high;
  33     __le32 format_version;
  34     __le32 root_size;
  35     __u8  unused52[60 - 52];
  36 };
  37
  38 #define ADFS_DISCRECORD         (0xc00)
  39 #define ADFS_DR_OFFSET          (0x1c0)
  40 #define ADFS_DR_SIZE             60
  41 #define ADFS_DR_SIZE_BITS       (ADFS_DR_SIZE << 3)
  42
  43 #ifdef __KERNEL__
  44 /*
  45  * Calculate the boot block checksum on an ADFS drive.  Note that this will
  46  * appear to be correct if the sector contains all zeros, so also check that
  47  * the disk size is non-zero!!!
  48  */
  49 static inline int adfs_checkbblk(unsigned char *ptr)
  50 {
  51         unsigned int result = 0;
  52         unsigned char *p = ptr + 511;
  53
  54         do {
  55                 result = (result & 0xff) + (result >> 8);
  56                 result = result + *--p;
  57         } while (p != ptr);
  58
  59         return (result & 0xff) != ptr[511];
  60 }
  61 #endif
  62
  63 #endif