X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=include%2Flinux%2Ftimex.h;h=94f8faecdcbc75bc9a10ffc9fb2a97465480b76e;hb=5ad6468801d28c4d4ac9f48ec19297817c915f6a;hp=261381b5da82ae4400be2124e8da9b283d8c36be;hpb=0883d899ef862c1b0f8b2c2d38098470c193a3dd;p=safe%2Fjmp%2Flinux-2.6 diff --git a/include/linux/timex.h b/include/linux/timex.h index 261381b..94f8fae 100644 --- a/include/linux/timex.h +++ b/include/linux/timex.h @@ -53,45 +53,9 @@ #ifndef _LINUX_TIMEX_H #define _LINUX_TIMEX_H -#include #include -#include - -/* - * SHIFT_KG and SHIFT_KF establish the damping of the PLL and are chosen - * for a slightly underdamped convergence characteristic. SHIFT_KH - * establishes the damping of the FLL and is chosen by wisdom and black - * art. - * - * MAXTC establishes the maximum time constant of the PLL. With the - * SHIFT_KG and SHIFT_KF values given and a time constant range from - * zero to MAXTC, the PLL will converge in 15 minutes to 16 hours, - * respectively. - */ -#define SHIFT_PLL 4 /* PLL frequency factor (shift) */ -#define SHIFT_FLL 2 /* FLL frequency factor (shift) */ -#define MAXTC 10 /* maximum time constant (shift) */ - -/* - * The SHIFT_UPDATE define establishes the decimal point of the - * time_offset variable which represents the current offset with - * respect to standard time. - * - * SHIFT_USEC defines the scaling (shift) of the time_freq and - * time_tolerance variables, which represent the current frequency - * offset and maximum frequency tolerance. - */ -#define SHIFT_UPDATE (SHIFT_HZ + 1) /* time offset scale (shift) */ -#define SHIFT_USEC 16 /* frequency offset scale (shift) */ -#define SHIFT_NSEC 12 /* kernel frequency offset scale */ - -#define MAXPHASE 512000L /* max phase error (us) */ -#define MAXFREQ (512L << SHIFT_USEC) /* max frequency error (ppm) */ -#define MAXFREQ_NSEC (512000L << SHIFT_NSEC) /* max frequency error (ppb) */ -#define MINSEC 256 /* min interval between updates (s) */ -#define MAXSEC 2048 /* max interval between updates (s) */ -#define NTP_PHASE_LIMIT (MAXPHASE << 5) /* beyond max. dispersion */ +#define NTP_API 4 /* NTP API version */ /* * syscall interface - used (mainly by NTP daemon) @@ -121,9 +85,11 @@ struct timex { long errcnt; /* calibration errors (ro) */ long stbcnt; /* stability limit exceeded (ro) */ + int tai; /* TAI offset (ro) */ + int :32; int :32; int :32; int :32; int :32; int :32; int :32; int :32; - int :32; int :32; int :32; int :32; + int :32; int :32; int :32; }; /* @@ -135,18 +101,30 @@ struct timex { #define ADJ_ESTERROR 0x0008 /* estimated time error */ #define ADJ_STATUS 0x0010 /* clock status */ #define ADJ_TIMECONST 0x0020 /* pll time constant */ +#define ADJ_TAI 0x0080 /* set TAI offset */ +#define ADJ_MICRO 0x1000 /* select microsecond resolution */ +#define ADJ_NANO 0x2000 /* select nanosecond resolution */ #define ADJ_TICK 0x4000 /* tick value */ + +#ifdef __KERNEL__ +#define ADJ_ADJTIME 0x8000 /* switch between adjtime/adjtimex modes */ +#define ADJ_OFFSET_SINGLESHOT 0x0001 /* old-fashioned adjtime */ +#define ADJ_OFFSET_READONLY 0x2000 /* read-only adjtime */ +#else #define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime */ +#define ADJ_OFFSET_SS_READ 0xa001 /* read-only adjtime */ +#endif -/* xntp 3.4 compatibility names */ +/* NTP userland likes the MOD_ prefix better */ #define MOD_OFFSET ADJ_OFFSET #define MOD_FREQUENCY ADJ_FREQUENCY #define MOD_MAXERROR ADJ_MAXERROR #define MOD_ESTERROR ADJ_ESTERROR #define MOD_STATUS ADJ_STATUS #define MOD_TIMECONST ADJ_TIMECONST -#define MOD_CLKB ADJ_TICK -#define MOD_CLKA ADJ_OFFSET_SINGLESHOT /* 0x8000 in original */ +#define MOD_TAI ADJ_TAI +#define MOD_MICRO ADJ_MICRO +#define MOD_NANO ADJ_NANO /* @@ -168,9 +146,13 @@ struct timex { #define STA_PPSERROR 0x0800 /* PPS signal calibration error (ro) */ #define STA_CLOCKERR 0x1000 /* clock hardware fault (ro) */ +#define STA_NANO 0x2000 /* resolution (0 = us, 1 = ns) (ro) */ +#define STA_MODE 0x4000 /* mode (0 = PLL, 1 = FLL) (ro) */ +#define STA_CLK 0x8000 /* clock source (0 = A, 1 = B) (ro) */ +/* read-only bits */ #define STA_RONLY (STA_PPSSIGNAL | STA_PPSJITTER | STA_PPSWANDER | \ - STA_PPSERROR | STA_CLOCKERR) /* read-only bits */ + STA_PPSERROR | STA_CLOCKERR | STA_NANO | STA_MODE | STA_CLK) /* * Clock states (time_state) @@ -184,9 +166,66 @@ struct timex { #define TIME_BAD TIME_ERROR /* bw compat */ #ifdef __KERNEL__ +#include +#include +#include + #include /* + * SHIFT_PLL is used as a dampening factor to define how much we + * adjust the frequency correction for a given offset in PLL mode. + * It also used in dampening the offset correction, to define how + * much of the current value in time_offset we correct for each + * second. Changing this value changes the stiffness of the ntp + * adjustment code. A lower value makes it more flexible, reducing + * NTP convergence time. A higher value makes it stiffer, increasing + * convergence time, but making the clock more stable. + * + * In David Mills' nanokernel reference implementation SHIFT_PLL is 4. + * However this seems to increase convergence time much too long. + * + * https://lists.ntp.org/pipermail/hackers/2008-January/003487.html + * + * In the above mailing list discussion, it seems the value of 4 + * was appropriate for other Unix systems with HZ=100, and that + * SHIFT_PLL should be decreased as HZ increases. However, Linux's + * clock steering implementation is HZ independent. + * + * Through experimentation, a SHIFT_PLL value of 2 was found to allow + * for fast convergence (very similar to the NTPv3 code used prior to + * v2.6.19), with good clock stability. + * + * + * SHIFT_FLL is used as a dampening factor to define how much we + * adjust the frequency correction for a given offset in FLL mode. + * In David Mills' nanokernel reference implementation SHIFT_FLL is 2. + * + * MAXTC establishes the maximum time constant of the PLL. + */ +#define SHIFT_PLL 2 /* PLL frequency factor (shift) */ +#define SHIFT_FLL 2 /* FLL frequency factor (shift) */ +#define MAXTC 10 /* maximum time constant (shift) */ + +/* + * SHIFT_USEC defines the scaling (shift) of the time_freq and + * time_tolerance variables, which represent the current frequency + * offset and maximum frequency tolerance. + */ +#define SHIFT_USEC 16 /* frequency offset scale (shift) */ +#define PPM_SCALE ((s64)NSEC_PER_USEC << (NTP_SCALE_SHIFT - SHIFT_USEC)) +#define PPM_SCALE_INV_SHIFT 19 +#define PPM_SCALE_INV ((1LL << (PPM_SCALE_INV_SHIFT + NTP_SCALE_SHIFT)) / \ + PPM_SCALE + 1) + +#define MAXPHASE 500000000L /* max phase error (ns) */ +#define MAXFREQ 500000 /* max frequency error (ns/s) */ +#define MAXFREQ_SCALED ((s64)MAXFREQ << NTP_SCALE_SHIFT) +#define MINSEC 256 /* min interval between updates (s) */ +#define MAXSEC 2048 /* max interval between updates (s) */ +#define NTP_PHASE_LIMIT ((MAXPHASE / NSEC_PER_USEC) << 5) /* beyond max. dispersion */ + +/* * kernel variables * Note: maximum error = NTP synch distance = dispersion + delay / 2; * estimated error = NTP dispersion. @@ -198,21 +237,14 @@ extern int tickadj; /* amount of adjustment per tick */ /* * phase-lock loop variables */ -extern int time_state; /* clock status */ extern int time_status; /* clock synchronization status bits */ -extern long time_offset; /* time adjustment (us) */ -extern long time_constant; /* pll time constant */ -extern long time_precision; /* clock precision (us) */ extern long time_maxerror; /* maximum error */ extern long time_esterror; /* estimated error */ -extern long time_freq; /* frequency offset (scaled ppm) */ -extern long time_reftime; /* time at last adjustment (s) */ - extern long time_adjust; /* The amount of adjtime left */ +extern void ntp_init(void); extern void ntp_clear(void); -extern void ntp_update_frequency(void); /** * ntp_synced - Returns 1 if the NTP status is not UNSYNC @@ -230,75 +262,26 @@ static inline int ntp_synced(void) __x < 0 ? -(-__x >> __s) : __x >> __s; \ }) +#define NTP_SCALE_SHIFT 32 -#ifdef CONFIG_TIME_INTERPOLATION - -#define TIME_SOURCE_CPU 0 -#define TIME_SOURCE_MMIO64 1 -#define TIME_SOURCE_MMIO32 2 -#define TIME_SOURCE_FUNCTION 3 - -/* For proper operations time_interpolator clocks must run slightly slower - * than the standard clock since the interpolator may only correct by having - * time jump forward during a tick. A slower clock is usually a side effect - * of the integer divide of the nanoseconds in a second by the frequency. - * The accuracy of the division can be increased by specifying a shift. - * However, this may cause the clock not to be slow enough. - * The interpolator will self-tune the clock by slowing down if no - * resets occur or speeding up if the time jumps per analysis cycle - * become too high. - * - * Setting jitter compensates for a fluctuating timesource by comparing - * to the last value read from the timesource to insure that an earlier value - * is not returned by a later call. The price to pay - * for the compensation is that the timer routines are not as scalable anymore. - */ - -struct time_interpolator { - u16 source; /* time source flags */ - u8 shift; /* increases accuracy of multiply by shifting. */ - /* Note that bits may be lost if shift is set too high */ - u8 jitter; /* if set compensate for fluctuations */ - u32 nsec_per_cyc; /* set by register_time_interpolator() */ - void *addr; /* address of counter or function */ - u64 mask; /* mask the valid bits of the counter */ - unsigned long offset; /* nsec offset at last update of interpolator */ - u64 last_counter; /* counter value in units of the counter at last update */ - u64 last_cycle; /* Last timer value if TIME_SOURCE_JITTER is set */ - u64 frequency; /* frequency in counts/second */ - long drift; /* drift in parts-per-million (or -1) */ - unsigned long skips; /* skips forward */ - unsigned long ns_skipped; /* nanoseconds skipped */ - struct time_interpolator *next; -}; - -extern void register_time_interpolator(struct time_interpolator *); -extern void unregister_time_interpolator(struct time_interpolator *); -extern void time_interpolator_reset(void); -extern unsigned long time_interpolator_get_offset(void); -extern void time_interpolator_update(long delta_nsec); - -#else /* !CONFIG_TIME_INTERPOLATION */ - -static inline void time_interpolator_reset(void) -{ -} - -static inline void time_interpolator_update(long delta_nsec) -{ -} - -#endif /* !CONFIG_TIME_INTERPOLATION */ +#define NTP_INTERVAL_FREQ (HZ) +#define NTP_INTERVAL_LENGTH (NSEC_PER_SEC/NTP_INTERVAL_FREQ) -#define TICK_LENGTH_SHIFT 32 - -/* Returns how long ticks are at present, in ns / 2^(SHIFT_SCALE-10). */ -extern u64 current_tick_length(void); +/* Returns how long ticks are at present, in ns / 2^NTP_SCALE_SHIFT. */ +extern u64 tick_length; extern void second_overflow(void); extern void update_ntp_one_tick(void); extern int do_adjtimex(struct timex *); +/* Don't use! Compatibility define for existing users. */ +#define tickadj (500/HZ ? : 1) + +int read_current_timer(unsigned long *timer_val); + +/* The clock frequency of the i8253/i8254 PIT */ +#define PIT_TICK_RATE 1193182ul + #endif /* KERNEL */ #endif /* LINUX_TIMEX_H */