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/errno.h>
  21 #include <linux/init.h>
  22 #include <linux/module.h>
  23 #include <linux/sched.h>
  24 #include <linux/kernel.h>
  25 #include <linux/param.h>
  26 #include <linux/string.h>
  27 #include <linux/mm.h>
  28 #include <linux/interrupt.h>
  29 #include <linux/profile.h>
  30
  31 #include <asm/io.h>
  32 #include <asm/m32r.h>
  33
  34 #include <asm/hw_irq.h>
  35
  36 #ifdef CONFIG_SMP
  37 extern void send_IPI_allbutself(int, int);
  38 extern void smp_local_timer_interrupt(struct pt_regs *);
  39 #endif
  40
  41 extern unsigned long wall_jiffies;
  42 #define TICK_SIZE       (tick_nsec / 1000)
  43
  44 /*
  45  * Change this if you have some constant time drift
  46  */
  47
  48 /* This is for machines which generate the exact clock. */
  49 #define USECS_PER_JIFFY (1000000/HZ)
  50
  51 static unsigned long latch;
  52
  53 static unsigned long do_gettimeoffset(void)
  54 {
  55         unsigned long  elapsed_time = 0;  /* [us] */
  56
  57 #if defined(CONFIG_CHIP_M32102) || defined(CONFIG_CHIP_XNUX2) \
  58         || defined(CONFIG_CHIP_VDEC2) || defined(CONFIG_CHIP_M32700) \
  59         || defined(CONFIG_CHIP_OPSP) || defined(CONFIG_CHIP_M32104)
  60 #ifndef CONFIG_SMP
  61
  62         unsigned long count;
  63
  64         /* timer count may underflow right here */
  65         count = inl(M32R_MFT2CUT_PORTL);
  66
  67         if (inl(M32R_ICU_CR18_PORTL) & 0x00000100)      /* underflow check */
  68                 count = 0;
  69
  70         count = (latch - count) * TICK_SIZE;
  71         elapsed_time = (count + latch / 2) / latch;
  72         /* NOTE: LATCH is equal to the "interval" value (= reload count). */
  73
  74 #else /* CONFIG_SMP */
  75         unsigned long count;
  76         static unsigned long p_jiffies = -1;
  77         static unsigned long p_count = 0;
  78
  79         /* timer count may underflow right here */
  80         count = inl(M32R_MFT2CUT_PORTL);
  81
  82         if (jiffies == p_jiffies && count > p_count)
  83                 count = 0;
  84
  85         p_jiffies = jiffies;
  86         p_count = count;
  87
  88         count = (latch - count) * TICK_SIZE;
  89         elapsed_time = (count + latch / 2) / latch;
  90         /* NOTE: LATCH is equal to the "interval" value (= reload count). */
  91 #endif /* CONFIG_SMP */
  92 #elif defined(CONFIG_CHIP_M32310)
  93 #warning do_gettimeoffse not implemented
  94 #else
  95 #error no chip configuration
  96 #endif
  97
  98         return elapsed_time;
  99 }
 100
 101 /*
 102  * This version of gettimeofday has near microsecond resolution.
 103  */
 104 void do_gettimeofday(struct timeval *tv)
 105 {
 106         unsigned long seq;
 107         unsigned long usec, sec;
 108         unsigned long max_ntp_tick = tick_usec - tickadj;
 109
 110         do {
 111                 unsigned long lost;
 112
 113                 seq = read_seqbegin(&xtime_lock);
 114
 115                 usec = do_gettimeoffset();
 116                 lost = jiffies - wall_jiffies;
 117
 118                 /*
 119                  * If time_adjust is negative then NTP is slowing the clock
 120                  * so make sure not to go into next possible interval.
 121                  * Better to lose some accuracy than have time go backwards..
 122                  */
 123                 if (unlikely(time_adjust < 0)) {
 124                         usec = min(usec, max_ntp_tick);
 125                         if (lost)
 126                                 usec += lost * max_ntp_tick;
 127                 } else if (unlikely(lost))
 128                         usec += lost * tick_usec;
 129
 130                 sec = xtime.tv_sec;
 131                 usec += (xtime.tv_nsec / 1000);
 132         } while (read_seqretry(&xtime_lock, seq));
 133
 134         while (usec >= 1000000) {
 135                 usec -= 1000000;
 136                 sec++;
 137         }
 138
 139         tv->tv_sec = sec;
 140         tv->tv_usec = usec;
 141 }
 142
 143 EXPORT_SYMBOL(do_gettimeofday);
 144
 145 int do_settimeofday(struct timespec *tv)
 146 {
 147         time_t wtm_sec, sec = tv->tv_sec;
 148         long wtm_nsec, nsec = tv->tv_nsec;
 149
 150         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 151                 return -EINVAL;
 152
 153         write_seqlock_irq(&xtime_lock);
 154         /*
 155          * This is revolting. We need to set "xtime" correctly. However, the
 156          * value in this location is the value at the most recent update of
 157          * wall time.  Discover what correction gettimeofday() would have
 158          * made, and then undo it!
 159          */
 160         nsec -= do_gettimeoffset() * NSEC_PER_USEC;
 161         nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
 162
 163         wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
 164         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 165
 166         set_normalized_timespec(&xtime, sec, nsec);
 167         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 168
 169         ntp_clear();
 170         write_sequnlock_irq(&xtime_lock);
 171         clock_was_set();
 172
 173         return 0;
 174 }
 175
 176 EXPORT_SYMBOL(do_settimeofday);
 177
 178 /*
 179  * In order to set the CMOS clock precisely, set_rtc_mmss has to be
 180  * called 500 ms after the second nowtime has started, because when
 181  * nowtime is written into the registers of the CMOS clock, it will
 182  * jump to the next second precisely 500 ms later. Check the Motorola
 183  * MC146818A or Dallas DS12887 data sheet for details.
 184  *
 185  * BUG: This routine does not handle hour overflow properly; it just
 186  *      sets the minutes. Usually you won't notice until after reboot!
 187  */
 188 static inline int set_rtc_mmss(unsigned long nowtime)
 189 {
 190         return 0;
 191 }
 192
 193 /* last time the cmos clock got updated */
 194 static long last_rtc_update = 0;
 195
 196 /*
 197  * timer_interrupt() needs to keep up the real-time clock,
 198  * as well as call the "do_timer()" routine every clocktick
 199  */
 200 irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 201 {
 202 #ifndef CONFIG_SMP
 203         profile_tick(CPU_PROFILING, regs);
 204 #endif
 205         do_timer(regs);
 206
 207 #ifndef CONFIG_SMP
 208         update_process_times(user_mode(regs));
 209 #endif
 210         /*
 211          * If we have an externally synchronized Linux clock, then update
 212          * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
 213          * called as close as possible to 500 ms before the new second starts.
 214          */
 215         write_seqlock(&xtime_lock);
 216         if (ntp_synced()
 217                 && xtime.tv_sec > last_rtc_update + 660
 218                 && (xtime.tv_nsec / 1000) >= 500000 - ((unsigned)TICK_SIZE) / 2
 219                 && (xtime.tv_nsec / 1000) <= 500000 + ((unsigned)TICK_SIZE) / 2)
 220         {
 221                 if (set_rtc_mmss(xtime.tv_sec) == 0)
 222                         last_rtc_update = xtime.tv_sec;
 223                 else    /* do it again in 60 s */
 224                         last_rtc_update = xtime.tv_sec - 600;
 225         }
 226         write_sequnlock(&xtime_lock);
 227         /* As we return to user mode fire off the other CPU schedulers..
 228            this is basically because we don't yet share IRQ's around.
 229            This message is rigged to be safe on the 386 - basically it's
 230            a hack, so don't look closely for now.. */
 231
 232 #ifdef CONFIG_SMP
 233         smp_local_timer_interrupt(regs);
 234         smp_send_timer();
 235 #endif
 236
 237         return IRQ_HANDLED;
 238 }
 239
 240 struct irqaction irq0 = { timer_interrupt, SA_INTERRUPT, CPU_MASK_NONE,
 241                           "MFT2", NULL, NULL };
 242
 243 void __init time_init(void)
 244 {
 245         unsigned int epoch, year, mon, day, hour, min, sec;
 246
 247         sec = min = hour = day = mon = year = 0;
 248         epoch = 0;
 249
 250         year = 23;
 251         mon = 4;
 252         day = 17;
 253
 254         /* Attempt to guess the epoch.  This is the same heuristic as in rtc.c
 255            so no stupid things will happen to timekeeping.  Who knows, maybe
 256            Ultrix also uses 1952 as epoch ...  */
 257         if (year > 10 && year < 44)
 258                 epoch = 1980;
 259         else if (year < 96)
 260                 epoch = 1952;
 261         year += epoch;
 262
 263         xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
 264         xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
 265         set_normalized_timespec(&wall_to_monotonic,
 266                 -xtime.tv_sec, -xtime.tv_nsec);
 267
 268 #if defined(CONFIG_CHIP_M32102) || defined(CONFIG_CHIP_XNUX2) \
 269         || defined(CONFIG_CHIP_VDEC2) || defined(CONFIG_CHIP_M32700) \
 270         || defined(CONFIG_CHIP_OPSP) || defined(CONFIG_CHIP_M32104)
 271
 272         /* M32102 MFT setup */
 273         setup_irq(M32R_IRQ_MFT2, &irq0);
 274         {
 275                 unsigned long bus_clock;
 276                 unsigned short divide;
 277
 278                 bus_clock = boot_cpu_data.bus_clock;
 279                 divide = boot_cpu_data.timer_divide;
 280                 latch = (bus_clock/divide + HZ / 2) / HZ;
 281
 282                 printk("Timer start : latch = %ld\n", latch);
 283
 284                 outl((M32R_MFTMOD_CC_MASK | M32R_MFTMOD_TCCR \
 285                         |M32R_MFTMOD_CSSEL011), M32R_MFT2MOD_PORTL);
 286                 outl(latch, M32R_MFT2RLD_PORTL);
 287                 outl(latch, M32R_MFT2CUT_PORTL);
 288                 outl(0, M32R_MFT2CMPRLD_PORTL);
 289                 outl((M32R_MFTCR_MFT2MSK|M32R_MFTCR_MFT2EN), M32R_MFTCR_PORTL);
 290         }
 291
 292 #elif defined(CONFIG_CHIP_M32310)
 293 #warning time_init not implemented
 294 #else
 295 #error no chip configuration
 296 #endif
 297 }
 298
 299 /*
 300  *  Scheduler clock - returns current time in nanosec units.
 301  */
 302 unsigned long long sched_clock(void)
 303 {
 304         return (unsigned long long)jiffies * (1000000000 / HZ);
 305 }