-#ifndef HEADER_TIMER_H
-#define HEADER_TIMER_H 1
+#ifndef DEVICES_TIMER_H
+#define DEVICES_TIMER_H
+#include <round.h>
#include <stdint.h>
+/* Number of timer interrupts per second. */
#define TIMER_FREQ 100
void timer_init (void);
+void timer_calibrate (void);
+
int64_t timer_ticks (void);
int64_t timer_elapsed (int64_t);
-void timer_msleep (int64_t ms);
-void timer_usleep (int64_t us);
-void timer_nsleep (int64_t ns);
+/* Sleep and yield the CPU to other threads. */
+void timer_sleep (int64_t ticks);
+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);
+
+void timer_print_stats (void);
-#endif /* timer.h */
+#endif /* devices/timer.h */