#include <linux/timex.h>
#include <linux/time.h>
#include <linux/list.h>
+#include <linux/cache.h>
+#include <linux/timer.h>
#include <asm/div64.h>
#include <asm/io.h>
/* clocksource cycle base type */
typedef u64 cycle_t;
+struct clocksource;
/**
* struct clocksource - hardware abstraction for a free running counter
* subtraction of non 64 bit counters
* @mult: cycle to nanosecond multiplier
* @shift: cycle to nanosecond divisor (power of two)
- * @update_callback: called when safe to alter clocksource values
- * @is_continuous: defines if clocksource is free-running.
- * @interval_cycles: Used internally by timekeeping core, please ignore.
- * @interval_snsecs: Used internally by timekeeping core, please ignore.
+ * @flags: flags describing special properties
+ * @vread: vsyscall based read
+ * @resume: resume function for the clocksource, if necessary
+ * @cycle_interval: Used internally by timekeeping core, please ignore.
+ * @xtime_interval: Used internally by timekeeping core, please ignore.
*/
struct clocksource {
+ /*
+ * First part of structure is read mostly
+ */
char *name;
struct list_head list;
int rating;
cycle_t mask;
u32 mult;
u32 shift;
- int (*update_callback)(void);
- int is_continuous;
+ unsigned long flags;
+ cycle_t (*vread)(void);
+ void (*resume)(void);
+#ifdef CONFIG_IA64
+ void *fsys_mmio; /* used by fsyscall asm code */
+#define CLKSRC_FSYS_MMIO_SET(mmio, addr) ((mmio) = (addr))
+#else
+#define CLKSRC_FSYS_MMIO_SET(mmio, addr) do { } while (0)
+#endif
/* timekeeping specific data, ignore */
- cycle_t interval_cycles;
- u64 interval_snsecs;
+ cycle_t cycle_interval;
+ u64 xtime_interval;
+ /*
+ * Second part is written at each timer interrupt
+ * Keep it in a different cache line to dirty no
+ * more than one cache line.
+ */
+ cycle_t cycle_last ____cacheline_aligned_in_smp;
+ u64 xtime_nsec;
+ s64 error;
+
+#ifdef CONFIG_CLOCKSOURCE_WATCHDOG
+ /* Watchdog related data, used by the framework */
+ struct list_head wd_list;
+ cycle_t wd_last;
+#endif
};
+extern struct clocksource *clock; /* current clocksource */
+
+/*
+ * Clock source flags bits::
+ */
+#define CLOCK_SOURCE_IS_CONTINUOUS 0x01
+#define CLOCK_SOURCE_MUST_VERIFY 0x02
+
+#define CLOCK_SOURCE_WATCHDOG 0x10
+#define CLOCK_SOURCE_VALID_FOR_HRES 0x20
+
/* simplify initialization of mask field */
-#define CLOCKSOURCE_MASK(bits) (cycle_t)(bits<64 ? ((1ULL<<bits)-1) : -1)
+#define CLOCKSOURCE_MASK(bits) (cycle_t)((bits) < 64 ? ((1ULL<<(bits))-1) : -1)
/**
* clocksource_khz2mult - calculates mult from khz and shift
* Unless you're the timekeeping code, you should not be using this!
*/
static inline void clocksource_calculate_interval(struct clocksource *c,
- unsigned long length_nsec)
+ unsigned long length_nsec)
{
u64 tmp;
tmp += c->mult/2;
do_div(tmp, c->mult);
- c->interval_cycles = (cycle_t)tmp;
- if(c->interval_cycles == 0)
- c->interval_cycles = 1;
+ c->cycle_interval = (cycle_t)tmp;
+ if (c->cycle_interval == 0)
+ c->cycle_interval = 1;
- c->interval_snsecs = (u64)c->interval_cycles * c->mult;
+ c->xtime_interval = (u64)c->cycle_interval * c->mult;
}
-/**
- * error_aproximation - calculates an error adjustment for a given error
- *
- * @error: Error value (unsigned)
- * @unit: Adjustment unit
- *
- * For a given error value, this function takes the adjustment unit
- * and uses binary approximation to return a power of two adjustment value.
- *
- * This function is only for use by the the make_ntp_adj() function
- * and you must hold a write on the xtime_lock when calling.
- */
-static inline int error_aproximation(u64 error, u64 unit)
+/* used to install a new clocksource */
+extern int clocksource_register(struct clocksource*);
+extern void clocksource_unregister(struct clocksource*);
+extern void clocksource_touch_watchdog(void);
+extern struct clocksource* clocksource_get_next(void);
+extern void clocksource_change_rating(struct clocksource *cs, int rating);
+extern void clocksource_resume(void);
+
+#ifdef CONFIG_GENERIC_TIME_VSYSCALL
+extern void update_vsyscall(struct timespec *ts, struct clocksource *c);
+extern void update_vsyscall_tz(void);
+#else
+static inline void update_vsyscall(struct timespec *ts, struct clocksource *c)
{
- static int saved_adj = 0;
- u64 adjusted_unit = unit << saved_adj;
-
- if (error > (adjusted_unit * 2)) {
- /* large error, so increment the adjustment factor */
- saved_adj++;
- } else if (error > adjusted_unit) {
- /* just right, don't touch it */
- } else if (saved_adj) {
- /* small error, so drop the adjustment factor */
- saved_adj--;
- return 0;
- }
-
- return saved_adj;
}
-
-/**
- * make_ntp_adj - Adjusts the specified clocksource for a given error
- *
- * @clock: Pointer to clock to be adjusted
- * @cycles_delta: Current unacounted cycle delta
- * @error: Pointer to current error value
- *
- * Returns clock shifted nanosecond adjustment to be applied against
- * the accumulated time value (ie: xtime).
- *
- * If the error value is large enough, this function calulates the
- * (power of two) adjustment value, and adjusts the clock's mult and
- * interval_snsecs values accordingly.
- *
- * However, since there may be some unaccumulated cycles, to avoid
- * time inconsistencies we must adjust the accumulation value
- * accordingly.
- *
- * This is not very intuitive, so the following proof should help:
- * The basic timeofday algorithm: base + cycle * mult
- * Thus:
- * new_base + cycle * new_mult = old_base + cycle * old_mult
- * new_base = old_base + cycle * old_mult - cycle * new_mult
- * new_base = old_base + cycle * (old_mult - new_mult)
- * new_base - old_base = cycle * (old_mult - new_mult)
- * base_delta = cycle * (old_mult - new_mult)
- * base_delta = cycle * (mult_delta)
- *
- * Where mult_delta is the adjustment value made to mult
- *
- */
-static inline s64 make_ntp_adj(struct clocksource *clock,
- cycles_t cycles_delta, s64* error)
+static inline void update_vsyscall_tz(void)
{
- s64 ret = 0;
- if (*error > ((s64)clock->interval_cycles+1)/2) {
- /* calculate adjustment value */
- int adjustment = error_aproximation(*error,
- clock->interval_cycles);
- /* adjust clock */
- clock->mult += 1 << adjustment;
- clock->interval_snsecs += clock->interval_cycles << adjustment;
-
- /* adjust the base and error for the adjustment */
- ret = -(cycles_delta << adjustment);
- *error -= clock->interval_cycles << adjustment;
- /* XXX adj error for cycle_delta offset? */
- } else if ((-(*error)) > ((s64)clock->interval_cycles+1)/2) {
- /* calculate adjustment value */
- int adjustment = error_aproximation(-(*error),
- clock->interval_cycles);
- /* adjust clock */
- clock->mult -= 1 << adjustment;
- clock->interval_snsecs -= clock->interval_cycles << adjustment;
-
- /* adjust the base and error for the adjustment */
- ret = cycles_delta << adjustment;
- *error += clock->interval_cycles << adjustment;
- /* XXX adj error for cycle_delta offset? */
- }
- return ret;
}
-
-
-/* used to install a new clocksource */
-int clocksource_register(struct clocksource*);
-void clocksource_reselect(void);
-struct clocksource* clocksource_get_next(void);
+#endif
#endif /* _LINUX_CLOCKSOURCE_H */
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