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timekeeping: Introduce struct timekeeper

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Add struct timekeeper to keep the internal values timekeeping.c needs
in regard to the currently selected clock source. This moves the
timekeeping intervals, xtime_nsec and the ntp error value from struct
clocksource to struct timekeeper. The raw_time is removed from the
clocksource as well. It gets treated like xtime as a global variable.
Eventually xtime raw_time should be moved to struct timekeeper.

[ tglx: minor cleanup ]

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: John Stultz <johnstul@us.ibm.com>
Cc: Daniel Walker <dwalker@fifo99.com>
LKML-Reference: <20090814134809.613209842@de.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Martin Schwidefsky 2009-08-14 15:47:26 +02:00 • committed by Thomas Gleixner
parent c55c87c892
commit 155ec60226
4 changed files with 165 additions and 133 deletions
Download patch file Download diff file Expand all files Collapse all files

54
include/linux/clocksource.h
View file

@ -155,8 +155,6 @@ extern u64 timecounter_cyc2time(struct timecounter *tc,
* @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 {
/*
@ -182,19 +180,12 @@ struct clocksource {
#define CLKSRC_FSYS_MMIO_SET(mmio, addr) do { } while (0)
#endif
/* timekeeping specific data, ignore */
cycle_t cycle_interval;
u64 xtime_interval;
u32 raw_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;
struct timespec raw_time;
#ifdef CONFIG_CLOCKSOURCE_WATCHDOG
/* Watchdog related data, used by the framework */
@ -203,8 +194,6 @@ struct clocksource {
#endif
};
extern struct clocksource *clock; /* current clocksource */
/*
* Clock source flags bits::
*/
@ -270,50 +259,15 @@ static inline u32 clocksource_hz2mult(u32 hz, u32 shift_constant)
}
/**
* cyc2ns - converts clocksource cycles to nanoseconds
* @cs: Pointer to clocksource
* @cycles: Cycles
* clocksource_cyc2ns - converts clocksource cycles to nanoseconds
*
* Uses the clocksource and ntp ajdustment to convert cycle_ts to nanoseconds.
* Converts cycles to nanoseconds, using the given mult and shift.
*
* XXX - This could use some mult_lxl_ll() asm optimization
*/
static inline s64 cyc2ns(struct clocksource *cs, cycle_t cycles)
static inline s64 clocksource_cyc2ns(cycle_t cycles, u32 mult, u32 shift)
{
u64 ret = (u64)cycles;
ret = (ret * cs->mult) >> cs->shift;
return ret;
}
/**
* clocksource_calculate_interval - Calculates a clocksource interval struct
*
* @c: Pointer to clocksource.
* @length_nsec: Desired interval length in nanoseconds.
*
* Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
* pair and interval request.
*
* 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)
{
u64 tmp;
/* Do the ns -> cycle conversion first, using original mult */
tmp = length_nsec;
tmp <<= c->shift;
tmp += c->mult_orig/2;
do_div(tmp, c->mult_orig);
c->cycle_interval = (cycle_t)tmp;
if (c->cycle_interval == 0)
c->cycle_interval = 1;
/* Go back from cycles -> shifted ns, this time use ntp adjused mult */
c->xtime_interval = (u64)c->cycle_interval * c->mult;
c->raw_interval = ((u64)c->cycle_interval * c->mult_orig) >> c->shift;
return ((u64) cycles * mult) >> shift;
}