2 * linux/arch/parisc/kernel/time.c
4 * Copyright (C) 1991, 1992, 1995 Linus Torvalds
5 * Modifications for ARM (C) 1994, 1995, 1996,1997 Russell King
6 * Copyright (C) 1999 SuSE GmbH, (Philipp Rumpf, prumpf@tux.org)
8 * 1994-07-02 Alan Modra
9 * fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
10 * 1998-12-20 Updated NTP code according to technical memorandum Jan '96
11 * "A Kernel Model for Precision Timekeeping" by Dave Mills
13 #include <linux/config.h>
14 #include <linux/errno.h>
15 #include <linux/module.h>
16 #include <linux/sched.h>
17 #include <linux/kernel.h>
18 #include <linux/param.h>
19 #include <linux/string.h>
21 #include <linux/interrupt.h>
22 #include <linux/time.h>
23 #include <linux/init.h>
24 #include <linux/smp.h>
25 #include <linux/profile.h>
27 #include <asm/uaccess.h>
30 #include <asm/param.h>
34 #include <linux/timex.h>
36 u64 jiffies_64 = INITIAL_JIFFIES;
38 EXPORT_SYMBOL(jiffies_64);
40 /* xtime and wall_jiffies keep wall-clock time */
41 extern unsigned long wall_jiffies;
43 static long clocktick; /* timer cycles per tick */
47 extern void smp_do_timer(struct pt_regs *regs);
51 parisc_do_profile(struct pt_regs *regs)
53 unsigned long pc = regs->iaoq[0];
55 extern unsigned long prof_cpu_mask;
68 /* FIXME: when we have irq affinity to cpu, we need to
69 * only look at the cpus specified in this mask
72 if (!((1 << smp_processor_id()) & prof_cpu_mask))
76 pc -= (unsigned long) &_stext;
79 * Don't ignore out-of-bounds PC values silently,
80 * put them into the last histogram slot, so if
81 * present, they will show up as a sharp peak.
83 if (pc > prof_len - 1)
85 atomic_inc((atomic_t *)&prof_buffer[pc]);
88 irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
93 int cpu = smp_processor_id();
95 parisc_do_profile(regs);
98 /* initialize next_tick to time at last clocktick */
99 next_tick = cpu_data[cpu].it_value;
101 /* since time passes between the interrupt and the mfctl()
102 * above, it is never true that last_tick + clocktick == now. If we
103 * never miss a clocktick, we could set next_tick = last_tick + clocktick
104 * but maybe we'll miss ticks, hence the loop.
106 * Variables are *signed*.
110 while((next_tick - now) < halftick) {
111 next_tick += clocktick;
114 mtctl(next_tick, 16);
115 cpu_data[cpu].it_value = next_tick;
122 write_seqlock(&xtime_lock);
124 write_sequnlock(&xtime_lock);
128 #ifdef CONFIG_CHASSIS_LCD_LED
129 /* Only schedule the led tasklet on cpu 0, and only if it
132 if (cpu == 0 && !atomic_read(&led_tasklet.count))
133 tasklet_schedule(&led_tasklet);
136 /* check soft power switch status */
137 if (cpu == 0 && !atomic_read(&power_tasklet.count))
138 tasklet_schedule(&power_tasklet);
143 /*** converted from ia64 ***/
145 * Return the number of micro-seconds that elapsed since the last
146 * update to wall time (aka xtime aka wall_jiffies). The xtime_lock
147 * must be at least read-locked when calling this routine.
149 static inline unsigned long
154 * FIXME: This won't work on smp because jiffies are updated by cpu 0.
155 * Once parisc-linux learns the cr16 difference between processors,
156 * this could be made to work.
161 /* it_value is the intended time of the next tick */
162 last_tick = cpu_data[smp_processor_id()].it_value;
164 /* Subtract one tick and account for possible difference between
165 * when we expected the tick and when it actually arrived.
168 last_tick -= clocktick * (jiffies - wall_jiffies + 1);
169 elapsed_cycles = mfctl(16) - last_tick;
171 /* the precision of this math could be improved */
172 return elapsed_cycles / (PAGE0->mem_10msec / 10000);
179 do_gettimeofday (struct timeval *tv)
181 unsigned long flags, seq, usec, sec;
184 seq = read_seqbegin_irqsave(&xtime_lock, flags);
185 usec = gettimeoffset();
187 usec += (xtime.tv_nsec / 1000);
188 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
190 while (usec >= 1000000) {
199 EXPORT_SYMBOL(do_gettimeofday);
202 do_settimeofday (struct timespec *tv)
204 time_t wtm_sec, sec = tv->tv_sec;
205 long wtm_nsec, nsec = tv->tv_nsec;
207 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
210 write_seqlock_irq(&xtime_lock);
213 * This is revolting. We need to set "xtime"
214 * correctly. However, the value in this location is
215 * the value at the most recent update of wall time.
216 * Discover what correction gettimeofday would have
217 * done, and then undo it!
219 nsec -= gettimeoffset() * 1000;
221 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
222 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
224 set_normalized_timespec(&xtime, sec, nsec);
225 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
227 time_adjust = 0; /* stop active adjtime() */
228 time_status |= STA_UNSYNC;
229 time_maxerror = NTP_PHASE_LIMIT;
230 time_esterror = NTP_PHASE_LIMIT;
232 write_sequnlock_irq(&xtime_lock);
236 EXPORT_SYMBOL(do_settimeofday);
239 * XXX: We can do better than this.
240 * Returns nanoseconds
243 unsigned long long sched_clock(void)
245 return (unsigned long long)jiffies * (1000000000 / HZ);
249 void __init time_init(void)
251 unsigned long next_tick;
252 static struct pdc_tod tod_data;
254 clocktick = (100 * PAGE0->mem_10msec) / HZ;
255 halftick = clocktick / 2;
257 /* Setup clock interrupt timing */
259 next_tick = mfctl(16);
260 next_tick += clocktick;
261 cpu_data[smp_processor_id()].it_value = next_tick;
263 /* kick off Itimer (CR16) */
264 mtctl(next_tick, 16);
266 if(pdc_tod_read(&tod_data) == 0) {
267 write_seqlock_irq(&xtime_lock);
268 xtime.tv_sec = tod_data.tod_sec;
269 xtime.tv_nsec = tod_data.tod_usec * 1000;
270 set_normalized_timespec(&wall_to_monotonic,
271 -xtime.tv_sec, -xtime.tv_nsec);
272 write_sequnlock_irq(&xtime_lock);
274 printk(KERN_ERR "Error reading tod clock\n");