[MIPS] time: Helpers to compute clocksource/event shift and mult values.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

2 files changed, 36 insertions, 8 deletions

diff --git a/arch/mips/kernel/time.c b/arch/mips/kernel/time.c
index ca38fb0faed3..c4e6866d5cbc 100644
--- a/arch/mips/kernel/time.c
+++ b/arch/mips/kernel/time.c
@@ -171,25 +171,48 @@ struct clocksource clocksource_mips = {
         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
-static void __init init_mips_clocksource(void)
+void __init clocksource_set_clock(struct clocksource *cs, unsigned int clock)
 {
         u64 temp;
         u32 shift;
 
-        if (!mips_hpt_frequency || clocksource_mips.read == null_hpt_read)
-                return;
+        /* Find a shift value */
+        for (shift = 32; shift > 0; shift--) {
+                temp = (u64) NSEC_PER_SEC << shift;
+                do_div(temp, clock);
+                if ((temp >> 32) == 0)
+                        break;
+        }
+        cs->shift = shift;
+        cs->mult = (u32) temp;
+}
+
+void __cpuinit clockevent_set_clock(struct clock_event_device *cd,
+        unsigned int clock)
+{
+        u64 temp;
+        u32 shift;
 
-        /* Calclate a somewhat reasonable rating value */
-        clocksource_mips.rating = 200 + mips_hpt_frequency / 10000000;
         /* Find a shift value */
         for (shift = 32; shift > 0; shift--) {
                 temp = (u64) NSEC_PER_SEC << shift;
-                do_div(temp, mips_hpt_frequency);
+                do_div(temp, clock);
                 if ((temp >> 32) == 0)
                         break;
         }
-        clocksource_mips.shift = shift;
-        clocksource_mips.mult = (u32)temp;
+        cd->shift = shift;
+        cd->mult = (u32) temp;
+}
+
+static void __init init_mips_clocksource(void)
+{
+        if (!mips_hpt_frequency || clocksource_mips.read == null_hpt_read)
+                return;
+
+        /* Calclate a somewhat reasonable rating value */
+        clocksource_mips.rating = 200 + mips_hpt_frequency / 10000000;
+
+        clocksource_set_clock(&clocksource_mips, mips_hpt_frequency);
 
         clocksource_register(&clocksource_mips);
 }
diff --git a/include/asm-mips/time.h b/include/asm-mips/time.h
index cf76f4f7435f..bc47af313bcd 100644
--- a/include/asm-mips/time.h
+++ b/include/asm-mips/time.h
@@ -21,6 +21,7 @@
 #include <linux/ptrace.h>
 #include <linux/rtc.h>
 #include <linux/spinlock.h>
+#include <linux/clockchips.h>
 #include <linux/clocksource.h>
 
 extern spinlock_t rtc_lock;
@@ -83,4 +84,8 @@ static inline void mips_clockevent_init(void)
 }
 #endif
 
+extern void clocksource_set_clock(struct clocksource *cs, unsigned int clock);
+extern void clockevent_set_clock(struct clock_event_device *cd,
+                unsigned int clock);
+
 #endif /* _ASM_TIME_H */