1 files changed, 37 insertions, 9 deletions

diff --git a/arch/s390/include/asm/timex.h b/arch/s390/include/asm/timex.h
index fba4d66788a..8ad8af91503 100644
--- a/arch/s390/include/asm/timex.h
+++ b/arch/s390/include/asm/timex.h
@@ -15,7 +15,7 @@
 #define TOD_UNIX_EPOCH 0x7d91048bca000000ULL
 
 /* Inline functions for clock register access. */
-static inline int set_clock(__u64 time)
+static inline int set_tod_clock(__u64 time)
 {
 	int cc;
 
@@ -27,7 +27,7 @@ static inline int set_clock(__u64 time)
 	return cc;
 }
 
-static inline int store_clock(__u64 *time)
+static inline int store_tod_clock(__u64 *time)
 {
 	int cc;
 
@@ -71,7 +71,7 @@ static inline void local_tick_enable(unsigned long long comp)
 
 typedef unsigned long long cycles_t;
 
-static inline unsigned long long get_clock(void)
+static inline unsigned long long get_tod_clock(void)
 {
 	unsigned long long clk;
 
@@ -83,21 +83,21 @@ static inline unsigned long long get_clock(void)
 	return clk;
 }
 
-static inline void get_clock_ext(char *clk)
+static inline void get_tod_clock_ext(char *clk)
 {
 	asm volatile("stcke %0" : "=Q" (*clk) : : "cc");
 }
 
-static inline unsigned long long get_clock_xt(void)
+static inline unsigned long long get_tod_clock_xt(void)
 {
 	unsigned char clk[16];
-	get_clock_ext(clk);
+	get_tod_clock_ext(clk);
 	return *((unsigned long long *)&clk[1]);
 }
 
 static inline cycles_t get_cycles(void)
 {
-	return (cycles_t) get_clock() >> 2;
+	return (cycles_t) get_tod_clock() >> 2;
 }
 
 int get_sync_clock(unsigned long long *clock);
@@ -123,9 +123,37 @@ extern u64 sched_clock_base_cc;
  * function, otherwise the returned value is not guaranteed to
  * be monotonic.
  */
-static inline unsigned long long get_clock_monotonic(void)
+static inline unsigned long long get_tod_clock_monotonic(void)
 {
-	return get_clock_xt() - sched_clock_base_cc;
+	return get_tod_clock_xt() - sched_clock_base_cc;
+}
+
+/**
+ * tod_to_ns - convert a TOD format value to nanoseconds
+ * @todval: to be converted TOD format value
+ * Returns: number of nanoseconds that correspond to the TOD format value
+ *
+ * Converting a 64 Bit TOD format value to nanoseconds means that the value
+ * must be divided by 4.096. In order to achieve that we multiply with 125
+ * and divide by 512:
+ *
+ *    ns = (todval * 125) >> 9;
+ *
+ * In order to avoid an overflow with the multiplication we can rewrite this.
+ * With a split todval == 2^32 * th + tl (th upper 32 bits, tl lower 32 bits)
+ * we end up with
+ *
+ *    ns = ((2^32 * th + tl) * 125 ) >> 9;
+ * -> ns = (2^23 * th * 125) + ((tl * 125) >> 9);
+ *
+ */
+static inline unsigned long long tod_to_ns(unsigned long long todval)
+{
+	unsigned long long ns;
+
+	ns = ((todval >> 32) << 23) * 125;
+	ns += ((todval & 0xffffffff) * 125) >> 9;
+	return ns;
 }
 
 #endif