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