patch-2.4.20 linux-2.4.20/arch/parisc/kernel/time.c
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- Lines: 255
- Date:
Thu Nov 28 15:53:10 2002
- Orig file:
linux-2.4.19/arch/parisc/kernel/time.c
- Orig date:
Wed Dec 6 11:46:39 2000
diff -urN linux-2.4.19/arch/parisc/kernel/time.c linux-2.4.20/arch/parisc/kernel/time.c
@@ -1,5 +1,5 @@
/*
- * linux/arch/arm/kernel/time.c
+ * linux/arch/parisc/kernel/time.c
*
* Copyright (C) 1991, 1992, 1995 Linus Torvalds
* Modifications for ARM (C) 1994, 1995, 1996,1997 Russell King
@@ -10,6 +10,7 @@
* 1998-12-20 Updated NTP code according to technical memorandum Jan '96
* "A Kernel Model for Precision Timekeeping" by Dave Mills
*/
+#include <linux/config.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
@@ -30,69 +31,208 @@
#include <linux/timex.h>
+/* xtime and wall_jiffies keep wall-clock time */
+extern unsigned long wall_jiffies;
extern rwlock_t xtime_lock;
-static int timer_value;
-static int timer_delta;
-static struct pdc_tod tod_data __attribute__((aligned(8)));
+static long clocktick; /* timer cycles per tick */
+static long halftick;
-void timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+#ifdef CONFIG_SMP
+extern void smp_do_timer(struct pt_regs *regs);
+#endif
+
+static inline void
+parisc_do_profile(unsigned long pc)
{
- int old;
- int lost = 0;
- int cr16;
-
- old = timer_value;
+ extern char _stext;
- cr16 = mfctl(16);
- while((timer_value - cr16) < (timer_delta / 2)) {
- timer_value += timer_delta;
- lost++;
- }
+ if (!prof_buffer)
+ return;
- mtctl(timer_value ,16);
+ pc -= (unsigned long) &_stext;
+ pc >>= prof_shift;
+ /*
+ * Don't ignore out-of-bounds PC values silently,
+ * put them into the last histogram slot, so if
+ * present, they will show up as a sharp peak.
+ */
+ if (pc > prof_len - 1)
+ pc = prof_len - 1;
+ atomic_inc((atomic_t *)&prof_buffer[pc]);
+}
+
+void timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+ long now = mfctl(16);
+ long next_tick;
+ int nticks;
+ int cpu = smp_processor_id();
+
+ /* initialize next_tick to time at last clocktick */
+
+ next_tick = cpu_data[cpu].it_value;
+
+ /* since time passes between the interrupt and the mfctl()
+ * above, it is never true that last_tick + clocktick == now. If we
+ * never miss a clocktick, we could set next_tick = last_tick + clocktick
+ * but maybe we'll miss ticks, hence the loop.
+ *
+ * Variables are *signed*.
+ */
+
+ nticks = 0;
+ while((next_tick - now) < halftick) {
+ next_tick += clocktick;
+ nticks++;
+ }
+ mtctl(next_tick, 16);
+ cpu_data[cpu].it_value = next_tick;
- do_timer(regs);
+ while (nticks--) {
+#ifdef CONFIG_SMP
+ smp_do_timer(regs);
+#endif
+ if (cpu == 0) {
+ extern int pc_in_user_space;
+ write_lock(&xtime_lock);
+#ifndef CONFIG_SMP
+ if (!user_mode(regs))
+ parisc_do_profile(regs->iaoq[0]);
+ else
+ parisc_do_profile(&pc_in_user_space);
+#endif
+ do_timer(regs);
+ write_unlock(&xtime_lock);
+ }
+ }
- led_interrupt_func();
+#ifdef CONFIG_CHASSIS_LCD_LED
+ /* Only schedule the led tasklet on cpu 0, and only if it
+ * is enabled.
+ */
+ if (cpu == 0 && !atomic_read(&led_tasklet.count))
+ tasklet_schedule(&led_tasklet);
+#endif
+
+ /* check soft power switch status */
+ if (cpu == 0 && !atomic_read(&power_tasklet.count))
+ tasklet_schedule(&power_tasklet);
}
-void do_gettimeofday(struct timeval *tv)
+/*** converted from ia64 ***/
+/*
+ * Return the number of micro-seconds that elapsed since the last
+ * update to wall time (aka xtime aka wall_jiffies). The xtime_lock
+ * must be at least read-locked when calling this routine.
+ */
+static inline unsigned long
+gettimeoffset (void)
{
- unsigned long flags;
-
+#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.
+ */
+ long last_tick;
+ long elapsed_cycles;
+
+ /* it_value is the intended time of the next tick */
+ last_tick = cpu_data[smp_processor_id()].it_value;
+
+ /* Subtract one tick and account for possible difference between
+ * when we expected the tick and when it actually arrived.
+ * (aka wall vs real)
+ */
+ last_tick -= clocktick * (jiffies - wall_jiffies + 1);
+ elapsed_cycles = mfctl(16) - last_tick;
+
+ /* the precision of this math could be improved */
+ return elapsed_cycles / (PAGE0->mem_10msec / 10000);
+#else
+ return 0;
+#endif
+}
+
+void
+do_gettimeofday (struct timeval *tv)
+{
+ unsigned long flags, usec, sec;
+
read_lock_irqsave(&xtime_lock, flags);
- tv->tv_sec = xtime.tv_sec;
- tv->tv_usec = xtime.tv_usec;
+ {
+ usec = gettimeoffset();
+
+ sec = xtime.tv_sec;
+ usec += xtime.tv_usec;
+ }
read_unlock_irqrestore(&xtime_lock, flags);
+ while (usec >= 1000000) {
+ usec -= 1000000;
+ ++sec;
+ }
+
+ tv->tv_sec = sec;
+ tv->tv_usec = usec;
}
-void do_settimeofday(struct timeval *tv)
+void
+do_settimeofday (struct timeval *tv)
{
write_lock_irq(&xtime_lock);
- xtime.tv_sec = tv->tv_sec;
- xtime.tv_usec = tv->tv_usec;
+ {
+ /*
+ * 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!
+ */
+ tv->tv_usec -= gettimeoffset();
+ tv->tv_usec -= (jiffies - wall_jiffies) * (1000000 / HZ);
+
+ while (tv->tv_usec < 0) {
+ tv->tv_usec += 1000000;
+ tv->tv_sec--;
+ }
+
+ xtime = *tv;
+ time_adjust = 0; /* stop active adjtime() */
+ time_status |= STA_UNSYNC;
+ time_maxerror = NTP_PHASE_LIMIT;
+ time_esterror = NTP_PHASE_LIMIT;
+ }
write_unlock_irq(&xtime_lock);
}
+
void __init time_init(void)
{
- timer_delta = (100 * PAGE0->mem_10msec) / HZ;
+ unsigned long next_tick;
+ static struct pdc_tod tod_data;
+
+ clocktick = (100 * PAGE0->mem_10msec) / HZ;
+ halftick = clocktick / 2;
- /* make the first timer interrupt go off in one second */
- timer_value = mfctl(16) + (HZ * timer_delta);
- mtctl(timer_value, 16);
+ /* Setup clock interrupt timing */
+ next_tick = mfctl(16);
+ next_tick += clocktick;
+ cpu_data[smp_processor_id()].it_value = next_tick;
+
+ /* kick off Itimer (CR16) */
+ mtctl(next_tick, 16);
if(pdc_tod_read(&tod_data) == 0) {
+ write_lock_irq(&xtime_lock);
xtime.tv_sec = tod_data.tod_sec;
xtime.tv_usec = tod_data.tod_usec;
+ write_unlock_irq(&xtime_lock);
} else {
printk(KERN_ERR "Error reading tod clock\n");
xtime.tv_sec = 0;
xtime.tv_usec = 0;
}
-
}
-
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