+void timer_msleep (int64_t milliseconds);
+void timer_usleep (int64_t microseconds);
+void timer_nsleep (int64_t nanoseconds);
+
+/* Busy waits. */
+void timer_mdelay (int64_t milliseconds);
+void timer_udelay (int64_t microseconds);
+void timer_ndelay (int64_t nanoseconds);