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[IA64] Convert to generic timekeeping/clocksource

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This is a merge of Peter Keilty's initial patch (which was
revived by Bob Picco) for this with Hidetoshi Seto's fixes
and scaling improvements.

Acked-by: Bob Picco <bob.picco@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This commit is contained in:
Tony Luck
2007-07-20 11:22:30 -07:00
parent 5bae7ac9fe
commit 0aa366f351
18 changed files with 334 additions and 174 deletions
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96
arch/ia64/kernel/time.c
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@@ -19,6 +19,7 @@
#include <linux/interrupt.h>
#include <linux/efi.h>
#include <linux/timex.h>
#include <linux/clocksource.h>
#include <asm/machvec.h>
#include <asm/delay.h>
@@ -28,6 +29,16 @@
#include <asm/sections.h>
#include <asm/system.h>
#include "fsyscall_gtod_data.h"
static cycle_t itc_get_cycles(void);
struct fsyscall_gtod_data_t fsyscall_gtod_data = {
.lock = SEQLOCK_UNLOCKED,
};
struct itc_jitter_data_t itc_jitter_data;
volatile int time_keeper_id = 0; /* smp_processor_id() of time-keeper */
#ifdef CONFIG_IA64_DEBUG_IRQ
@@ -37,11 +48,16 @@ EXPORT_SYMBOL(last_cli_ip);
#endif
static struct time_interpolator itc_interpolator = {
.shift = 16,
.mask = 0xffffffffffffffffLL,
.source = TIME_SOURCE_CPU
static struct clocksource clocksource_itc = {
.name = "itc",
.rating = 350,
.read = itc_get_cycles,
.mask = 0xffffffffffffffff,
.mult = 0, /*to be caluclated*/
.shift = 16,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static struct clocksource *itc_clocksource;
static irqreturn_t
timer_interrupt (int irq, void *dev_id)
@@ -210,8 +226,6 @@ ia64_init_itm (void)
+ itc_freq/2)/itc_freq;
if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) {
itc_interpolator.frequency = local_cpu_data->itc_freq;
itc_interpolator.drift = itc_drift;
#ifdef CONFIG_SMP
/* On IA64 in an SMP configuration ITCs are never accurately synchronized.
* Jitter compensation requires a cmpxchg which may limit
@@ -223,15 +237,50 @@ ia64_init_itm (void)
* even going backward) if the ITC offsets between the individual CPUs
* are too large.
*/
if (!nojitter) itc_interpolator.jitter = 1;
if (!nojitter)
itc_jitter_data.itc_jitter = 1;
#endif
register_time_interpolator(&itc_interpolator);
}
/* Setup the CPU local timer tick */
ia64_cpu_local_tick();
if (!itc_clocksource) {
/* Sort out mult/shift values: */
clocksource_itc.mult =
clocksource_hz2mult(local_cpu_data->itc_freq,
clocksource_itc.shift);
clocksource_register(&clocksource_itc);
itc_clocksource = &clocksource_itc;
}
}
static cycle_t itc_get_cycles()
{
u64 lcycle, now, ret;
if (!itc_jitter_data.itc_jitter)
return get_cycles();
lcycle = itc_jitter_data.itc_lastcycle;
now = get_cycles();
if (lcycle && time_after(lcycle, now))
return lcycle;
/*
* Keep track of the last timer value returned.
* In an SMP environment, you could lose out in contention of
* cmpxchg. If so, your cmpxchg returns new value which the
* winner of contention updated to. Use the new value instead.
*/
ret = cmpxchg(&itc_jitter_data.itc_lastcycle, lcycle, now);
if (unlikely(ret != lcycle))
return ret;
return now;
}
static struct irqaction timer_irqaction = {
.handler = timer_interrupt,
.flags = IRQF_DISABLED | IRQF_IRQPOLL,
@@ -307,3 +356,34 @@ ia64_setup_printk_clock(void)
if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT))
ia64_printk_clock = ia64_itc_printk_clock;
}
void update_vsyscall(struct timespec *wall, struct clocksource *c)
{
unsigned long flags;
write_seqlock_irqsave(&fsyscall_gtod_data.lock, flags);
/* copy fsyscall clock data */
fsyscall_gtod_data.clk_mask = c->mask;
fsyscall_gtod_data.clk_mult = c->mult;
fsyscall_gtod_data.clk_shift = c->shift;
fsyscall_gtod_data.clk_fsys_mmio = c->fsys_mmio;
fsyscall_gtod_data.clk_cycle_last = c->cycle_last;
/* copy kernel time structures */
fsyscall_gtod_data.wall_time.tv_sec = wall->tv_sec;
fsyscall_gtod_data.wall_time.tv_nsec = wall->tv_nsec;
fsyscall_gtod_data.monotonic_time.tv_sec = wall_to_monotonic.tv_sec
+ wall->tv_sec;
fsyscall_gtod_data.monotonic_time.tv_nsec = wall_to_monotonic.tv_nsec
+ wall->tv_nsec;
/* normalize */
while (fsyscall_gtod_data.monotonic_time.tv_nsec >= NSEC_PER_SEC) {
fsyscall_gtod_data.monotonic_time.tv_nsec -= NSEC_PER_SEC;
fsyscall_gtod_data.monotonic_time.tv_sec++;
}
write_sequnlock_irqrestore(&fsyscall_gtod_data.lock, flags);
}