diff options
Diffstat (limited to 'kernel/time/clocksource.c')
| -rw-r--r-- | kernel/time/clocksource.c | 42 |
1 files changed, 31 insertions, 11 deletions
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index f08e99c1d56..6519cf62d9c 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -113,7 +113,7 @@ EXPORT_SYMBOL_GPL(timecounter_cyc2time); * @shift: pointer to shift variable * @from: frequency to convert from * @to: frequency to convert to - * @minsec: guaranteed runtime conversion range in seconds + * @maxsec: guaranteed runtime conversion range in seconds * * The function evaluates the shift/mult pair for the scaled math * operations of clocksources and clockevents. @@ -122,7 +122,7 @@ EXPORT_SYMBOL_GPL(timecounter_cyc2time); * NSEC_PER_SEC == 1GHz and @from is the counter frequency. For clock * event @to is the counter frequency and @from is NSEC_PER_SEC. * - * The @minsec conversion range argument controls the time frame in + * The @maxsec conversion range argument controls the time frame in * seconds which must be covered by the runtime conversion with the * calculated mult and shift factors. This guarantees that no 64bit * overflow happens when the input value of the conversion is @@ -131,7 +131,7 @@ EXPORT_SYMBOL_GPL(timecounter_cyc2time); * factors. */ void -clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec) +clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 maxsec) { u64 tmp; u32 sft, sftacc= 32; @@ -140,7 +140,7 @@ clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec) * Calculate the shift factor which is limiting the conversion * range: */ - tmp = ((u64)minsec * from) >> 32; + tmp = ((u64)maxsec * from) >> 32; while (tmp) { tmp >>=1; sftacc--; @@ -152,6 +152,7 @@ clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec) */ for (sft = 32; sft > 0; sft--) { tmp = (u64) to << sft; + tmp += from / 2; do_div(tmp, from); if ((tmp >> sftacc) == 0) break; @@ -531,7 +532,7 @@ static u64 clocksource_max_deferment(struct clocksource *cs) return max_nsecs - (max_nsecs >> 5); } -#ifdef CONFIG_GENERIC_TIME +#ifndef CONFIG_ARCH_USES_GETTIMEOFFSET /** * clocksource_select - Select the best clocksource available @@ -577,7 +578,7 @@ static void clocksource_select(void) } } -#else /* CONFIG_GENERIC_TIME */ +#else /* !CONFIG_ARCH_USES_GETTIMEOFFSET */ static inline void clocksource_select(void) { } @@ -639,19 +640,18 @@ static void clocksource_enqueue(struct clocksource *cs) #define MAX_UPDATE_LENGTH 5 /* Seconds */ /** - * __clocksource_register_scale - Used to install new clocksources + * __clocksource_updatefreq_scale - Used update clocksource with new freq * @t: clocksource to be registered * @scale: Scale factor multiplied against freq to get clocksource hz * @freq: clocksource frequency (cycles per second) divided by scale * - * Returns -EBUSY if registration fails, zero otherwise. + * This should only be called from the clocksource->enable() method. * * This *SHOULD NOT* be called directly! Please use the - * clocksource_register_hz() or clocksource_register_khz helper functions. + * clocksource_updatefreq_hz() or clocksource_updatefreq_khz helper functions. */ -int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq) +void __clocksource_updatefreq_scale(struct clocksource *cs, u32 scale, u32 freq) { - /* * Ideally we want to use some of the limits used in * clocksource_max_deferment, to provide a more informed @@ -662,7 +662,27 @@ int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq) NSEC_PER_SEC/scale, MAX_UPDATE_LENGTH*scale); cs->max_idle_ns = clocksource_max_deferment(cs); +} +EXPORT_SYMBOL_GPL(__clocksource_updatefreq_scale); + +/** + * __clocksource_register_scale - Used to install new clocksources + * @t: clocksource to be registered + * @scale: Scale factor multiplied against freq to get clocksource hz + * @freq: clocksource frequency (cycles per second) divided by scale + * + * Returns -EBUSY if registration fails, zero otherwise. + * + * This *SHOULD NOT* be called directly! Please use the + * clocksource_register_hz() or clocksource_register_khz helper functions. + */ +int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq) +{ + + /* Initialize mult/shift and max_idle_ns */ + __clocksource_updatefreq_scale(cs, scale, freq); + /* Add clocksource to the clcoksource list */ mutex_lock(&clocksource_mutex); clocksource_enqueue(cs); clocksource_select(); |