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[PARISC] GENERIC_TIME patchset for parisc

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Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
This commit is contained in:
Helge Deller 2007-01-02 23:54:16 +01:00 committed by Kyle McMartin
parent df47b4386a
commit 12df29b64c
2 changed files with 29 additions and 111 deletions
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4
arch/parisc/Kconfig
View File

@ -50,6 +50,10 @@ config GENERIC_CALIBRATE_DELAY
bool
default y
config GENERIC_TIME
bool
default y
config TIME_LOW_RES
bool
depends on SMP

136
arch/parisc/kernel/time.c
View File

@ -22,6 +22,7 @@
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/profile.h>
#include <linux/clocksource.h>
#include <asm/uaccess.h>
#include <asm/io.h>
@ -172,121 +173,23 @@ unsigned long profile_pc(struct pt_regs *regs)
EXPORT_SYMBOL(profile_pc);
/*
* Return the number of micro-seconds that elapsed since the last
* update to wall time (aka xtime). The xtime_lock
* must be at least read-locked when calling this routine.
*/
static inline unsigned long gettimeoffset (void)
/* clock source code */
static cycle_t read_cr16(void)
{
#ifndef CONFIG_SMP
/*
* FIXME: This won't work on smp because jiffies are updated by cpu 0.
* Once parisc-linux learns the cr16 difference between processors,
* this could be made to work.
*/
unsigned long now;
unsigned long prev_tick;
unsigned long next_tick;
unsigned long elapsed_cycles;
unsigned long usec;
unsigned long cpuid = smp_processor_id();
unsigned long cpt = clocktick;
next_tick = cpu_data[cpuid].it_value;
now = mfctl(16); /* Read the hardware interval timer. */
prev_tick = next_tick - cpt;
/* Assume Scenario 1: "now" is later than prev_tick. */
elapsed_cycles = now - prev_tick;
/* aproximate HZ with shifts. Intended math is "(elapsed/clocktick) > HZ" */
#if HZ == 1000
if (elapsed_cycles > (cpt << 10) )
#elif HZ == 250
if (elapsed_cycles > (cpt << 8) )
#elif HZ == 100
if (elapsed_cycles > (cpt << 7) )
#else
#warn WTF is HZ set to anyway?
if (elapsed_cycles > (HZ * cpt) )
#endif
{
/* Scenario 3: clock ticks are missing. */
printk (KERN_CRIT "gettimeoffset(CPU %ld): missing %ld ticks!"
" cycles %lX prev/now/next %lX/%lX/%lX clock %lX\n",
cpuid, elapsed_cycles / cpt,
elapsed_cycles, prev_tick, now, next_tick, cpt);
}
/* FIXME: Can we improve the precision? Not with PAGE0. */
usec = (elapsed_cycles * 10000) / PAGE0->mem_10msec;
return usec;
#else
return 0;
#endif
return get_cycles();
}
void
do_gettimeofday (struct timeval *tv)
{
unsigned long flags, seq, usec, sec;
static struct clocksource clocksource_cr16 = {
.name = "cr16",
.rating = 300,
.read = read_cr16,
.mask = CLOCKSOURCE_MASK(BITS_PER_LONG),
.mult = 0, /* to be set */
.shift = 22,
.is_continuous = 1,
};
/* Hold xtime_lock and adjust timeval. */
do {
seq = read_seqbegin_irqsave(&xtime_lock, flags);
usec = gettimeoffset();
sec = xtime.tv_sec;
usec += (xtime.tv_nsec / 1000);
} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
/* Move adjusted usec's into sec's. */
while (usec >= USEC_PER_SEC) {
usec -= USEC_PER_SEC;
++sec;
}
/* Return adjusted result. */
tv->tv_sec = sec;
tv->tv_usec = usec;
}
EXPORT_SYMBOL(do_gettimeofday);
int
do_settimeofday (struct timespec *tv)
{
time_t wtm_sec, sec = tv->tv_sec;
long wtm_nsec, nsec = tv->tv_nsec;
if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
return -EINVAL;
write_seqlock_irq(&xtime_lock);
{
/*
* This is revolting. We need to set "xtime"
* correctly. However, the value in this location is
* the value at the most recent update of wall time.
* Discover what correction gettimeofday would have
* done, and then undo it!
*/
nsec -= gettimeoffset() * 1000;
wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
set_normalized_timespec(&xtime, sec, nsec);
set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
ntp_clear();
}
write_sequnlock_irq(&xtime_lock);
clock_was_set();
return 0;
}
EXPORT_SYMBOL(do_settimeofday);
/*
* XXX: We can do better than this.
@ -312,11 +215,22 @@ void __init start_cpu_itimer(void)
void __init time_init(void)
{
static struct pdc_tod tod_data;
unsigned long current_cr16_khz;
clocktick = (100 * PAGE0->mem_10msec) / HZ;
start_cpu_itimer(); /* get CPU 0 started */
/* register at clocksource framework */
current_cr16_khz = PAGE0->mem_10msec/10; /* kHz */
clocksource_cr16.mult = clocksource_khz2mult(current_cr16_khz,
clocksource_cr16.shift);
/* lower the rating if we already know its unstable: */
if (num_online_cpus()>1)
clocksource_cr16.rating = 200;
clocksource_register(&clocksource_cr16);
if (pdc_tod_read(&tod_data) == 0) {
unsigned long flags;