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

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Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Ralf Baechle 2007-10-19 08:13:08 +01:00
parent f887b93e17
commit 93c846f904
2 changed files with 38 additions and 10 deletions
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43
arch/mips/kernel/time.c
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@ -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;
/* 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;
/* 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;
}
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;
/* Find a shift value */
for (shift = 32; shift > 0; shift--) {
temp = (u64) NSEC_PER_SEC << shift;
do_div(temp, mips_hpt_frequency);
if ((temp >> 32) == 0)
break;
}
clocksource_mips.shift = shift;
clocksource_mips.mult = (u32)temp;
clocksource_set_clock(&clocksource_mips, mips_hpt_frequency);
clocksource_register(&clocksource_mips);
}

5
include/asm-mips/time.h
View File

@ -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 */