#include <linux/init.h>
#include <linux/smp.h>
#include <linux/profile.h>
+#include <linux/clocksource.h>
#include <asm/uaccess.h>
#include <asm/io.h>
* cycles after the IT fires. But it's arbitrary how much time passes
* before we call it "late". I've picked one second.
*/
- if (ticks_elapsed > HZ) {
+ if (unlikely(ticks_elapsed > HZ)) {
/* Scenario 3: very long delay? bad in any case */
printk (KERN_CRIT "timer_interrupt(CPU %d): delayed!"
" cycles %lX rem %lX "
write_sequnlock(&xtime_lock);
}
- /* check soft power switch status */
- if (cpu == 0 && !atomic_read(&power_tasklet.count))
- tasklet_schedule(&power_tasklet);
-
return IRQ_HANDLED;
}
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)
-{
-#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. */
+/* clock source code */
- prev_tick = next_tick - cpt;
+static cycle_t read_cr16(void)
+{
+ return get_cycles();
+}
- /* Assume Scenario 1: "now" is later than prev_tick. */
- elapsed_cycles = now - prev_tick;
+static int cr16_update_callback(void);
-/* 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);
- }
+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,
+ .update_callback = cr16_update_callback,
+ .is_continuous = 1,
+};
- /* FIXME: Can we improve the precision? Not with PAGE0. */
- usec = (elapsed_cycles * 10000) / PAGE0->mem_10msec;
- return usec;
-#else
- return 0;
-#endif
-}
-
-void
-do_gettimeofday (struct timeval *tv)
+static int cr16_update_callback(void)
{
- unsigned long flags, seq, usec, sec;
-
- /* 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;
+ int change = 0;
+
+ /* since the cr16 cycle counters are not syncronized across CPUs,
+ we'll check if we should switch to a safe clocksource: */
+ if (clocksource_cr16.rating != 0 && num_online_cpus() > 1) {
+ clocksource_cr16.rating = 0;
+ clocksource_reselect();
+ change = 1;
}
- /* Return adjusted result. */
- tv->tv_sec = sec;
- tv->tv_usec = usec;
+ return change;
}
-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);
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);
+ clocksource_register(&clocksource_cr16);
+
if (pdc_tod_read(&tod_data) == 0) {
unsigned long flags;
projects / linux-drm-fsl-dcu.git / blobdiff