1 files changed, 50 insertions, 0 deletions

diff --git a/include/asm-x86/timer.h b/include/asm-x86/timer.h
new file mode 100644
index 000000000000..0db7e994fb8b
--- /dev/null
+++ b/include/asm-x86/timer.h
@@ -0,0 +1,50 @@
+#ifndef _ASMi386_TIMER_H
+#define _ASMi386_TIMER_H
+#include <linux/init.h>
+#include <linux/pm.h>
+
+#define TICK_SIZE (tick_nsec / 1000)
+
+unsigned long long native_sched_clock(void);
+unsigned long native_calculate_cpu_khz(void);
+
+extern int timer_ack;
+extern int no_timer_check;
+extern int recalibrate_cpu_khz(void);
+
+#ifndef CONFIG_PARAVIRT
+#define calculate_cpu_khz() native_calculate_cpu_khz()
+#endif
+
+/* Accellerators for sched_clock()
+ * convert from cycles(64bits) => nanoseconds (64bits)
+ *  basic equation:
+ *              ns = cycles / (freq / ns_per_sec)
+ *              ns = cycles * (ns_per_sec / freq)
+ *              ns = cycles * (10^9 / (cpu_khz * 10^3))
+ *              ns = cycles * (10^6 / cpu_khz)
+ *
+ *      Then we use scaling math (suggested by george@mvista.com) to get:
+ *              ns = cycles * (10^6 * SC / cpu_khz) / SC
+ *              ns = cycles * cyc2ns_scale / SC
+ *
+ *      And since SC is a constant power of two, we can convert the div
+ *  into a shift.
+ *
+ *  We can use khz divisor instead of mhz to keep a better percision, since
+ *  cyc2ns_scale is limited to 10^6 * 2^10, which fits in 32 bits.
+ *  (mathieu.desnoyers@polymtl.ca)
+ *
+ *                      -johnstul@us.ibm.com "math is hard, lets go shopping!"
+ */
+extern unsigned long cyc2ns_scale __read_mostly;
+
+#define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */
+
+static inline unsigned long long cycles_2_ns(unsigned long long cyc)
+{
+        return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR;
+}
+
+
+#endif