1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ADFS_FS_H
3 #define _ADFS_FS_H
4 
5 #include <uapi/linux/adfs_fs.h>
6 
7 /*
8  * Calculate the boot block checksum on an ADFS drive.  Note that this will
9  * appear to be correct if the sector contains all zeros, so also check that
10  * the disk size is non-zero!!!
11  */
adfs_checkbblk(unsigned char * ptr)12 static inline int adfs_checkbblk(unsigned char *ptr)
13 {
14 	unsigned int result = 0;
15 	unsigned char *p = ptr + 511;
16 
17 	do {
18 	        result = (result & 0xff) + (result >> 8);
19         	result = result + *--p;
20 	} while (p != ptr);
21 
22 	return (result & 0xff) != ptr[511];
23 }
24 #endif
25