diff options
Diffstat (limited to 'include/linux/clocksource.h')
| -rw-r--r-- | include/linux/clocksource.h | 127 |
1 files changed, 17 insertions, 110 deletions
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index abcafaa20b86..135509821c39 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -18,8 +18,6 @@ #include <asm/div64.h> #include <asm/io.h> -/* clocksource cycle base type */ -typedef u64 cycle_t; struct clocksource; struct module; @@ -28,106 +26,6 @@ struct module; #endif /** - * struct cyclecounter - hardware abstraction for a free running counter - * Provides completely state-free accessors to the underlying hardware. - * Depending on which hardware it reads, the cycle counter may wrap - * around quickly. Locking rules (if necessary) have to be defined - * by the implementor and user of specific instances of this API. - * - * @read: returns the current cycle value - * @mask: bitmask for two's complement - * subtraction of non 64 bit counters, - * see CLOCKSOURCE_MASK() helper macro - * @mult: cycle to nanosecond multiplier - * @shift: cycle to nanosecond divisor (power of two) - */ -struct cyclecounter { - cycle_t (*read)(const struct cyclecounter *cc); - cycle_t mask; - u32 mult; - u32 shift; -}; - -/** - * struct timecounter - layer above a %struct cyclecounter which counts nanoseconds - * Contains the state needed by timecounter_read() to detect - * cycle counter wrap around. Initialize with - * timecounter_init(). Also used to convert cycle counts into the - * corresponding nanosecond counts with timecounter_cyc2time(). Users - * of this code are responsible for initializing the underlying - * cycle counter hardware, locking issues and reading the time - * more often than the cycle counter wraps around. The nanosecond - * counter will only wrap around after ~585 years. - * - * @cc: the cycle counter used by this instance - * @cycle_last: most recent cycle counter value seen by - * timecounter_read() - * @nsec: continuously increasing count - */ -struct timecounter { - const struct cyclecounter *cc; - cycle_t cycle_last; - u64 nsec; -}; - -/** - * cyclecounter_cyc2ns - converts cycle counter cycles to nanoseconds - * @cc: Pointer to cycle counter. - * @cycles: Cycles - * - * XXX - This could use some mult_lxl_ll() asm optimization. Same code - * as in cyc2ns, but with unsigned result. - */ -static inline u64 cyclecounter_cyc2ns(const struct cyclecounter *cc, - cycle_t cycles) -{ - u64 ret = (u64)cycles; - ret = (ret * cc->mult) >> cc->shift; - return ret; -} - -/** - * timecounter_init - initialize a time counter - * @tc: Pointer to time counter which is to be initialized/reset - * @cc: A cycle counter, ready to be used. - * @start_tstamp: Arbitrary initial time stamp. - * - * After this call the current cycle register (roughly) corresponds to - * the initial time stamp. Every call to timecounter_read() increments - * the time stamp counter by the number of elapsed nanoseconds. - */ -extern void timecounter_init(struct timecounter *tc, - const struct cyclecounter *cc, - u64 start_tstamp); - -/** - * timecounter_read - return nanoseconds elapsed since timecounter_init() - * plus the initial time stamp - * @tc: Pointer to time counter. - * - * In other words, keeps track of time since the same epoch as - * the function which generated the initial time stamp. - */ -extern u64 timecounter_read(struct timecounter *tc); - -/** - * timecounter_cyc2time - convert a cycle counter to same - * time base as values returned by - * timecounter_read() - * @tc: Pointer to time counter. - * @cycle_tstamp: a value returned by tc->cc->read() - * - * Cycle counts that are converted correctly as long as they - * fall into the interval [-1/2 max cycle count, +1/2 max cycle count], - * with "max cycle count" == cs->mask+1. - * - * This allows conversion of cycle counter values which were generated - * in the past. - */ -extern u64 timecounter_cyc2time(struct timecounter *tc, - cycle_t cycle_tstamp); - -/** * struct clocksource - hardware abstraction for a free running counter * Provides mostly state-free accessors to the underlying hardware. * This is the structure used for system time. @@ -158,6 +56,7 @@ extern u64 timecounter_cyc2time(struct timecounter *tc, * @shift: cycle to nanosecond divisor (power of two) * @max_idle_ns: max idle time permitted by the clocksource (nsecs) * @maxadj: maximum adjustment value to mult (~11%) + * @max_cycles: maximum safe cycle value which won't overflow on multiplication * @flags: flags describing special properties * @archdata: arch-specific data * @suspend: suspend function for the clocksource, if necessary @@ -178,7 +77,7 @@ struct clocksource { #ifdef CONFIG_ARCH_CLOCKSOURCE_DATA struct arch_clocksource_data archdata; #endif - + u64 max_cycles; const char *name; struct list_head list; int rating; @@ -280,7 +179,6 @@ static inline s64 clocksource_cyc2ns(cycle_t cycles, u32 mult, u32 shift) } -extern int clocksource_register(struct clocksource*); extern int clocksource_unregister(struct clocksource*); extern void clocksource_touch_watchdog(void); extern struct clocksource* clocksource_get_next(void); @@ -291,7 +189,7 @@ extern struct clocksource * __init clocksource_default_clock(void); extern void clocksource_mark_unstable(struct clocksource *cs); extern u64 -clocks_calc_max_nsecs(u32 mult, u32 shift, u32 maxadj, u64 mask); +clocks_calc_max_nsecs(u32 mult, u32 shift, u32 maxadj, u64 mask, u64 *max_cycles); extern void clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec); @@ -302,7 +200,16 @@ clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec); extern int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq); extern void -__clocksource_updatefreq_scale(struct clocksource *cs, u32 scale, u32 freq); +__clocksource_update_freq_scale(struct clocksource *cs, u32 scale, u32 freq); + +/* + * Don't call this unless you are a default clocksource + * (AKA: jiffies) and absolutely have to. + */ +static inline int __clocksource_register(struct clocksource *cs) +{ + return __clocksource_register_scale(cs, 1, 0); +} static inline int clocksource_register_hz(struct clocksource *cs, u32 hz) { @@ -314,14 +221,14 @@ static inline int clocksource_register_khz(struct clocksource *cs, u32 khz) return __clocksource_register_scale(cs, 1000, khz); } -static inline void __clocksource_updatefreq_hz(struct clocksource *cs, u32 hz) +static inline void __clocksource_update_freq_hz(struct clocksource *cs, u32 hz) { - __clocksource_updatefreq_scale(cs, 1, hz); + __clocksource_update_freq_scale(cs, 1, hz); } -static inline void __clocksource_updatefreq_khz(struct clocksource *cs, u32 khz) +static inline void __clocksource_update_freq_khz(struct clocksource *cs, u32 khz) { - __clocksource_updatefreq_scale(cs, 1000, khz); + __clocksource_update_freq_scale(cs, 1000, khz); } |
