arch/m32r/kernel/time.c

   1 /*
   2  *  linux/arch/m32r/kernel/time.c
   3  *
   4  *  Copyright (c) 2001, 2002  Hiroyuki Kondo, Hirokazu Takata,
   5  *                            Hitoshi Yamamoto
   6  *  Taken from i386 version.
   7  *    Copyright (C) 1991, 1992, 1995  Linus Torvalds
   8  *    Copyright (C) 1996, 1997, 1998  Ralf Baechle
   9  *
  10  *  This file contains the time handling details for PC-style clocks as
  11  *  found in some MIPS systems.
  12  *
  13  *  Some code taken from sh version.
  14  *    Copyright (C) 1999  Tetsuya Okada & Niibe Yutaka
  15  *    Copyright (C) 2000  Philipp Rumpf <prumpf@tux.org>
  16  */
  17
  18 #undef  DEBUG_TIMER
  19
  20 #include <linux/config.h>
  21 #include <linux/errno.h>
  22 #include <linux/init.h>
  23 #include <linux/module.h>
  24 #include <linux/sched.h>
  25 #include <linux/kernel.h>
  26 #include <linux/param.h>
  27 #include <linux/string.h>
  28 #include <linux/mm.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/profile.h>
  31
  32 #include <asm/io.h>
  33 #include <asm/m32r.h>
  34
  35 #include <asm/hw_irq.h>
  36
  37 #ifdef CONFIG_SMP
  38 extern void send_IPI_allbutself(int, int);
  39 extern void smp_local_timer_interrupt(struct pt_regs *);
  40 #endif
  41
  42 u64 jiffies_64 = INITIAL_JIFFIES;
  43
  44 EXPORT_SYMBOL(jiffies_64);
  45
  46 extern unsigned long wall_jiffies;
  47 #define TICK_SIZE       (tick_nsec / 1000)
  48
  49 /*
  50  * Change this if you have some constant time drift
  51  */
  52
  53 /* This is for machines which generate the exact clock. */
  54 #define USECS_PER_JIFFY (1000000/HZ)
  55
  56 static unsigned long latch;
  57
  58 static unsigned long do_gettimeoffset(void)
  59 {
  60         unsigned long  elapsed_time = 0;  /* [us] */
  61
  62 #if defined(CONFIG_CHIP_M32102) || defined(CONFIG_CHIP_XNUX2) \
  63         || defined(CONFIG_CHIP_VDEC2) || defined(CONFIG_CHIP_M32700) \
  64         || defined(CONFIG_CHIP_OPSP)
  65 #ifndef CONFIG_SMP
  66
  67         unsigned long count;
  68
  69         /* timer count may underflow right here */
  70         count = inl(M32R_MFT2CUT_PORTL);
  71
  72         if (inl(M32R_ICU_CR18_PORTL) & 0x00000100)      /* underflow check */
  73                 count = 0;
  74
  75         count = (latch - count) * TICK_SIZE;
  76         elapsed_time = (count + latch / 2) / latch;
  77         /* NOTE: LATCH is equal to the "interval" value (= reload count). */
  78
  79 #else /* CONFIG_SMP */
  80         unsigned long count;
  81         static unsigned long p_jiffies = -1;
  82         static unsigned long p_count = 0;
  83
  84         /* timer count may underflow right here */
  85         count = inl(M32R_MFT2CUT_PORTL);
  86
  87         if (jiffies == p_jiffies && count > p_count)
  88                 count = 0;
  89
  90         p_jiffies = jiffies;
  91         p_count = count;
  92
  93         count = (latch - count) * TICK_SIZE;
  94         elapsed_time = (count + latch / 2) / latch;
  95         /* NOTE: LATCH is equal to the "interval" value (= reload count). */
  96 #endif /* CONFIG_SMP */
  97 #elif defined(CONFIG_CHIP_M32310)
  98 #warning do_gettimeoffse not implemented
  99 #else
 100 #error no chip configuration
 101 #endif
 102
 103         return elapsed_time;
 104 }
 105
 106 /*
 107  * This version of gettimeofday has near microsecond resolution.
 108  */
 109 void do_gettimeofday(struct timeval *tv)
 110 {
 111         unsigned long seq;
 112         unsigned long usec, sec;
 113         unsigned long max_ntp_tick = tick_usec - tickadj;
 114
 115         do {
 116                 unsigned long lost;
 117
 118                 seq = read_seqbegin(&xtime_lock);
 119
 120                 usec = do_gettimeoffset();
 121                 lost = jiffies - wall_jiffies;
 122
 123                 /*
 124                  * If time_adjust is negative then NTP is slowing the clock
 125                  * so make sure not to go into next possible interval.
 126                  * Better to lose some accuracy than have time go backwards..
 127                  */
 128                 if (unlikely(time_adjust < 0)) {
 129                         usec = min(usec, max_ntp_tick);
 130                         if (lost)
 131                                 usec += lost * max_ntp_tick;
 132                 } else if (unlikely(lost))
 133                         usec += lost * tick_usec;
 134
 135                 sec = xtime.tv_sec;
 136                 usec += (xtime.tv_nsec / 1000);
 137         } while (read_seqretry(&xtime_lock, seq));
 138
 139         while (usec >= 1000000) {
 140                 usec -= 1000000;
 141                 sec++;
 142         }
 143
 144         tv->tv_sec = sec;
 145         tv->tv_usec = usec;
 146 }
 147
 148 EXPORT_SYMBOL(do_gettimeofday);
 149
 150 int do_settimeofday(struct timespec *tv)
 151 {
 152         time_t wtm_sec, sec = tv->tv_sec;
 153         long wtm_nsec, nsec = tv->tv_nsec;
 154
 155         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 156                 return -EINVAL;
 157
 158         write_seqlock_irq(&xtime_lock);
 159         /*
 160          * This is revolting. We need to set "xtime" correctly. However, the
 161          * value in this location is the value at the most recent update of
 162          * wall time.  Discover what correction gettimeofday() would have
 163          * made, and then undo it!
 164          */
 165         nsec -= do_gettimeoffset() * NSEC_PER_USEC;
 166         nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
 167
 168         wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
 169         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 170
 171         set_normalized_timespec(&xtime, sec, nsec);
 172         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 173
 174         time_adjust = 0;                /* stop active adjtime() */
 175         time_status |= STA_UNSYNC;
 176         time_maxerror = NTP_PHASE_LIMIT;
 177         time_esterror = NTP_PHASE_LIMIT;
 178         write_sequnlock_irq(&xtime_lock);
 179         clock_was_set();
 180
 181         return 0;
 182 }
 183
 184 EXPORT_SYMBOL(do_settimeofday);
 185
 186 /*
 187  * In order to set the CMOS clock precisely, set_rtc_mmss has to be
 188  * called 500 ms after the second nowtime has started, because when
 189  * nowtime is written into the registers of the CMOS clock, it will
 190  * jump to the next second precisely 500 ms later. Check the Motorola
 191  * MC146818A or Dallas DS12887 data sheet for details.
 192  *
 193  * BUG: This routine does not handle hour overflow properly; it just
 194  *      sets the minutes. Usually you won't notice until after reboot!
 195  */
 196 static inline int set_rtc_mmss(unsigned long nowtime)
 197 {
 198         return 0;
 199 }
 200
 201 /* last time the cmos clock got updated */
 202 static long last_rtc_update = 0;
 203
 204 /*
 205  * timer_interrupt() needs to keep up the real-time clock,
 206  * as well as call the "do_timer()" routine every clocktick
 207  */
 208 static inline void
 209 do_timer_interrupt(int irq, void *dev_id, struct pt_regs * regs)
 210 {
 211 #ifndef CONFIG_SMP
 212         profile_tick(CPU_PROFILING, regs);
 213 #endif
 214         do_timer(regs);
 215
 216 #ifndef CONFIG_SMP
 217         update_process_times(user_mode(regs));
 218 #endif
 219         /*
 220          * If we have an externally synchronized Linux clock, then update
 221          * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
 222          * called as close as possible to 500 ms before the new second starts.
 223          */
 224         if ((time_status & STA_UNSYNC) == 0
 225                 && xtime.tv_sec > last_rtc_update + 660
 226                 && (xtime.tv_nsec / 1000) >= 500000 - ((unsigned)TICK_SIZE) / 2
 227                 && (xtime.tv_nsec / 1000) <= 500000 + ((unsigned)TICK_SIZE) / 2)
 228         {
 229                 if (set_rtc_mmss(xtime.tv_sec) == 0)
 230                         last_rtc_update = xtime.tv_sec;
 231                 else    /* do it again in 60 s */
 232                         last_rtc_update = xtime.tv_sec - 600;
 233         }
 234         /* As we return to user mode fire off the other CPU schedulers..
 235            this is basically because we don't yet share IRQ's around.
 236            This message is rigged to be safe on the 386 - basically it's
 237            a hack, so don't look closely for now.. */
 238
 239 #ifdef CONFIG_SMP
 240         smp_local_timer_interrupt(regs);
 241 #endif
 242 }
 243
 244 irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 245 {
 246         write_seqlock(&xtime_lock);
 247         do_timer_interrupt(irq, NULL, regs);
 248         write_sequnlock(&xtime_lock);
 249
 250         return IRQ_HANDLED;
 251 }
 252
 253 struct irqaction irq0 = { timer_interrupt, SA_INTERRUPT, CPU_MASK_NONE,
 254                           "MFT2", NULL, NULL };
 255
 256 void __init time_init(void)
 257 {
 258         unsigned int epoch, year, mon, day, hour, min, sec;
 259
 260         sec = min = hour = day = mon = year = 0;
 261         epoch = 0;
 262
 263         year = 23;
 264         mon = 4;
 265         day = 17;
 266
 267         /* Attempt to guess the epoch.  This is the same heuristic as in rtc.c
 268            so no stupid things will happen to timekeeping.  Who knows, maybe
 269            Ultrix also uses 1952 as epoch ...  */
 270         if (year > 10 && year < 44)
 271                 epoch = 1980;
 272         else if (year < 96)
 273                 epoch = 1952;
 274         year += epoch;
 275
 276         xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
 277         xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
 278         set_normalized_timespec(&wall_to_monotonic,
 279                 -xtime.tv_sec, -xtime.tv_nsec);
 280
 281 #if defined(CONFIG_CHIP_M32102) || defined(CONFIG_CHIP_XNUX2) \
 282         || defined(CONFIG_CHIP_VDEC2) || defined(CONFIG_CHIP_M32700) \
 283         || defined(CONFIG_CHIP_OPSP)
 284
 285         /* M32102 MFT setup */
 286         setup_irq(M32R_IRQ_MFT2, &irq0);
 287         {
 288                 unsigned long bus_clock;
 289                 unsigned short divide;
 290
 291                 bus_clock = boot_cpu_data.bus_clock;
 292                 divide = boot_cpu_data.timer_divide;
 293                 latch = (bus_clock/divide + HZ / 2) / HZ;
 294
 295                 printk("Timer start : latch = %ld\n", latch);
 296
 297                 outl((M32R_MFTMOD_CC_MASK | M32R_MFTMOD_TCCR \
 298                         |M32R_MFTMOD_CSSEL011), M32R_MFT2MOD_PORTL);
 299                 outl(latch, M32R_MFT2RLD_PORTL);
 300                 outl(latch, M32R_MFT2CUT_PORTL);
 301                 outl(0, M32R_MFT2CMPRLD_PORTL);
 302                 outl((M32R_MFTCR_MFT2MSK|M32R_MFTCR_MFT2EN), M32R_MFTCR_PORTL);
 303         }
 304
 305 #elif defined(CONFIG_CHIP_M32310)
 306 #warning time_init not implemented
 307 #else
 308 #error no chip configuration
 309 #endif
 310 }
 311
 312 /*
 313  *  Scheduler clock - returns current time in nanosec units.
 314  */
 315 unsigned long long sched_clock(void)
 316 {
 317         return (unsigned long long)jiffies * (1000000000 / HZ);
 318 }