#define HDR_QUARKS 9
#define HDR_QUARK 10
-#define MKDEV(ma,mi) ((ma)<<8 | (mi))
+/* Device number manipulation macros from kernel source */
+#define MINORBITS 20
+#define MINORMASK ((1U << MINORBITS) - 1)
+#define MAJOR(dev) ((unsigned int) ((dev) >> MINORBITS))
+#define MINOR(dev) ((unsigned int) ((dev) & MINORMASK))
+#define MKDEV(ma,mi) (((ma) << MINORBITS) | (mi))
#endif // STATE_H