let drivers allocate memory at 64k physical boundary.

include/minix/syslib.h

@@ -84,6 +84,7 @@ _PROTOTYPE( int sys_sdevio, (int req, long port, endpoint_t proc_nr,
 _PROTOTYPE(void *alloc_contig, (size_t len, int flags, phys_bytes *phys));
 #define AC_ALIGN4K	0x01
 #define AC_LOWER16M	0x02
+#define AC_ALIGN64K	0x04
 
 /* Clock functionality: get system times or (un)schedule an alarm call. */
 _PROTOTYPE( int sys_times, (endpoint_t proc_nr, clock_t *user_time,

include/sys/mman.h

@@ -19,6 +19,7 @@
 #define MAP_PREALLOC	0x0008		/* not on-demand */
 #define MAP_CONTIG	0x0010		/* contiguous in physical memory */
 #define MAP_LOWER16M	0x0020		/* physically below 16MB */
+#define MAP_ALIGN64K	0x0040		/* physically aligned at 64kB */
 
 /* mmap() error return */
 #define MAP_FAILED      ((void *)-1)