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Linux/arch/v850/kernel/time.c

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  1 /*
  2  * linux/arch/v850/kernel/time.c -- Arch-dependent timer functions
  3  *
  4  *  Copyright (C) 1991, 1992, 1995, 2001, 2002  Linus Torvalds
  5  *
  6  * This file contains the v850-specific time handling details.
  7  * Most of the stuff is located in the machine specific files.
  8  *
  9  * 1997-09-10   Updated NTP code according to technical memorandum Jan '96
 10  *              "A Kernel Model for Precision Timekeeping" by Dave Mills
 11  */
 12 
 13 #include <linux/config.h> /* CONFIG_HEARTBEAT */
 14 #include <linux/errno.h>
 15 #include <linux/kernel.h>
 16 #include <linux/module.h>
 17 #include <linux/param.h>
 18 #include <linux/string.h>
 19 #include <linux/mm.h>
 20 #include <linux/interrupt.h>
 21 #include <linux/time.h>
 22 #include <linux/timex.h>
 23 #include <linux/profile.h>
 24 
 25 #include <asm/io.h>
 26 
 27 #include "mach.h"
 28 
 29 u64 jiffies_64 = INITIAL_JIFFIES;
 30 
 31 EXPORT_SYMBOL(jiffies_64);
 32 
 33 #define TICK_SIZE       (tick_nsec / 1000)
 34 
 35 /*
 36  * Scheduler clock - returns current time in nanosec units.
 37  */
 38 unsigned long long sched_clock(void)
 39 {
 40         return (unsigned long long)jiffies * (1000000000 / HZ);
 41 }
 42 
 43 static inline void do_profile (unsigned long pc)
 44 {
 45         if (prof_buffer && current->pid) {
 46                 extern int _stext;
 47                 pc -= (unsigned long) &_stext;
 48                 pc >>= prof_shift;
 49                 if (pc < prof_len)
 50                         ++prof_buffer[pc];
 51                 else
 52                 /*
 53                  * Don't ignore out-of-bounds PC values silently,
 54                  * put them into the last histogram slot, so if
 55                  * present, they will show up as a sharp peak.
 56                  */
 57                         ++prof_buffer[prof_len-1];
 58         }
 59 }
 60 
 61 /*
 62  * timer_interrupt() needs to keep up the real-time clock,
 63  * as well as call the "do_timer()" routine every clocktick
 64  */
 65 static irqreturn_t timer_interrupt (int irq, void *dummy, struct pt_regs *regs)
 66 {
 67 #if 0
 68         /* last time the cmos clock got updated */
 69         static long last_rtc_update=0;
 70 #endif
 71 
 72         /* may need to kick the hardware timer */
 73         if (mach_tick)
 74           mach_tick ();
 75 
 76         do_timer (regs);
 77 
 78         if (! user_mode (regs))
 79                 do_profile (regs->pc);
 80 
 81 #if 0
 82         /*
 83          * If we have an externally synchronized Linux clock, then update
 84          * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
 85          * called as close as possible to 500 ms before the new second starts.
 86          */
 87         if ((time_status & STA_UNSYNC) == 0 &&
 88             xtime.tv_sec > last_rtc_update + 660 &&
 89             (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
 90             (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
 91           if (set_rtc_mmss (xtime.tv_sec) == 0)
 92             last_rtc_update = xtime.tv_sec;
 93           else
 94             last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
 95         }
 96 #ifdef CONFIG_HEARTBEAT
 97         /* use power LED as a heartbeat instead -- much more useful
 98            for debugging -- based on the version for PReP by Cort */
 99         /* acts like an actual heart beat -- ie thump-thump-pause... */
100         if (mach_heartbeat) {
101             static unsigned cnt = 0, period = 0, dist = 0;
102 
103             if (cnt == 0 || cnt == dist)
104                 mach_heartbeat ( 1 );
105             else if (cnt == 7 || cnt == dist+7)
106                 mach_heartbeat ( 0 );
107 
108             if (++cnt > period) {
109                 cnt = 0;
110                 /* The hyperbolic function below modifies the heartbeat period
111                  * length in dependency of the current (5min) load. It goes
112                  * through the points f(0)=126, f(1)=86, f(5)=51,
113                  * f(inf)->30. */
114                 period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
115                 dist = period / 4;
116             }
117         }
118 #endif /* CONFIG_HEARTBEAT */
119 #endif /* 0 */
120 
121         return IRQ_HANDLED;
122 }
123 
124 /*
125  * This version of gettimeofday has near microsecond resolution.
126  */
127 void do_gettimeofday (struct timeval *tv)
128 {
129 #if 0 /* DAVIDM later if possible */
130         extern volatile unsigned long lost_ticks;
131         unsigned long lost;
132 #endif
133         unsigned long flags;
134         unsigned long usec, sec;
135         unsigned long seq;
136 
137         do {
138                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
139 
140 #if 0
141                 usec = mach_gettimeoffset ? mach_gettimeoffset () : 0;
142 #else
143                 usec = 0;
144 #endif
145 #if 0 /* DAVIDM later if possible */
146                 lost = lost_ticks;
147                 if (lost)
148                         usec += lost * (1000000/HZ);
149 #endif
150                 sec = xtime.tv_sec;
151                 usec += xtime.tv_nsec / 1000;
152         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
153 
154         while (usec >= 1000000) {
155                 usec -= 1000000;
156                 sec++;
157         }
158 
159         tv->tv_sec = sec;
160         tv->tv_usec = usec;
161 }
162 
163 EXPORT_SYMBOL(do_gettimeofday);
164 
165 int do_settimeofday(struct timespec *tv)
166 {
167         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
168                 return -EINVAL;
169 
170         write_seqlock_irq (&xtime_lock);
171 
172         /* This is revolting. We need to set the xtime.tv_nsec
173          * correctly. However, the value in this location is
174          * is value at the last tick.
175          * Discover what correction gettimeofday
176          * would have done, and then undo it!
177          */
178 #if 0
179         tv->tv_nsec -= mach_gettimeoffset() * 1000;
180 #endif
181 
182         while (tv->tv_nsec < 0) {
183                 tv->tv_nsec += NSEC_PER_SEC;
184                 tv->tv_sec--;
185         }
186 
187         xtime.tv_sec = tv->tv_sec;
188         xtime.tv_nsec = tv->tv_nsec;
189 
190         time_adjust = 0;                /* stop active adjtime () */
191         time_status |= STA_UNSYNC;
192         time_maxerror = NTP_PHASE_LIMIT;
193         time_esterror = NTP_PHASE_LIMIT;
194 
195         write_sequnlock_irq (&xtime_lock);
196         return 0;
197 }
198 
199 EXPORT_SYMBOL(do_settimeofday);
200 
201 static int timer_dev_id;
202 static struct irqaction timer_irqaction = {
203         timer_interrupt,
204         SA_INTERRUPT,
205         0,
206         "timer",
207         &timer_dev_id,
208         NULL
209 };
210 
211 void time_init (void)
212 {
213         mach_gettimeofday (&xtime);
214         mach_sched_init (&timer_irqaction);
215 }
216 

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