#ifndef _LINUX_TIMEX_H
#define _LINUX_TIMEX_H
-#include <linux/compiler.h>
#include <linux/time.h>
-#include <asm/param.h>
-#include <asm/timex.h>
-
-/*
- * 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_KG 6 /* phase factor (shift) */
-#define SHIFT_KF 16 /* PLL frequency factor (shift) */
-#define SHIFT_KH 2 /* FLL frequency factor (shift) */
-#define MAXTC 6 /* maximum time constant (shift) */
-
-/*
- * The SHIFT_SCALE define establishes the decimal point of the time_phase
- * variable which serves as an extension to the low-order bits of the
- * system clock variable. The SHIFT_UPDATE define establishes the decimal
- * point of the time_offset variable which represents the current offset
- * with respect to standard time. The FINENSEC define represents 1 nsec in
- * scaled units.
- *
- * SHIFT_USEC defines the scaling (shift) of the time_freq and
- * time_tolerance variables, which represent the current frequency
- * offset and maximum frequency tolerance.
- *
- * FINENSEC is 1 ns in SHIFT_UPDATE units of the time_phase variable.
- */
-#define SHIFT_SCALE 22 /* phase scale (shift) */
-#define SHIFT_UPDATE (SHIFT_KG + MAXTC) /* time offset scale (shift) */
-#define SHIFT_USEC 16 /* frequency offset scale (shift) */
-#define FINENSEC (1L << (SHIFT_SCALE - 10)) /* ~1 ns in phase units */
-
-#define MAXPHASE 512000L /* max phase error (us) */
-#define MAXFREQ (512L << SHIFT_USEC) /* max frequency error (ppm) */
-#define MINSEC 16L /* min interval between updates (s) */
-#define MAXSEC 1200L /* 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)
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;
};
/*
#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
/*
#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)
#define TIME_BAD TIME_ERROR /* bw compat */
#ifdef __KERNEL__
+#include <linux/compiler.h>
+#include <linux/types.h>
+#include <linux/param.h>
+
+#include <asm/timex.h>
+
+/*
+ * 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;
/*
* 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_tolerance; /* frequency tolerance (ppm) */
-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 long time_next_adjust; /* Value for time_adjust at next tick */
-/**
- * ntp_clear - Clears the NTP state variables
- *
- * Must be called while holding a write on the xtime_lock
- */
-static inline void ntp_clear(void)
-{
- time_adjust = 0; /* stop active adjtime() */
- time_status |= STA_UNSYNC;
- time_maxerror = NTP_PHASE_LIMIT;
- time_esterror = NTP_PHASE_LIMIT;
-}
+extern void ntp_init(void);
+extern void ntp_clear(void);
/**
* ntp_synced - Returns 1 if the NTP status is not UNSYNC
__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);
+#define NTP_INTERVAL_FREQ (HZ)
+#define NTP_INTERVAL_LENGTH (NSEC_PER_SEC/NTP_INTERVAL_FREQ)
-#else /* !CONFIG_TIME_INTERPOLATION */
+/* Returns how long ticks are at present, in ns / 2^NTP_SCALE_SHIFT. */
+extern u64 tick_length;
-static inline void
-time_interpolator_reset(void)
-{
-}
+extern void second_overflow(void);
+extern void update_ntp_one_tick(void);
+extern int do_adjtimex(struct timex *);
-#endif /* !CONFIG_TIME_INTERPOLATION */
+/* Don't use! Compatibility define for existing users. */
+#define tickadj (500/HZ ? : 1)
-/* Returns how long ticks are at present, in ns / 2^(SHIFT_SCALE-10). */
-extern u64 current_tick_length(void);
+int read_current_timer(unsigned long *timer_val);
-extern int do_adjtimex(struct timex *);
+/* The clock frequency of the i8253/i8254 PIT */
+#define PIT_TICK_RATE 1193182ul
#endif /* KERNEL */
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff