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  */
adfs_checkbblk(unsigned char * ptr)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
64