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 #if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE)
  37 /* this needs a better home */
  38 DEFINE_SPINLOCK(rtc_lock);
  39
  40 #ifdef CONFIG_RTC_DRV_CMOS_MODULE
  41 EXPORT_SYMBOL(rtc_lock);
  42 #endif
  43 #endif  /* pc-style 'CMOS' RTC support */
  44
  45 #ifdef CONFIG_SMP
  46 extern void smp_local_timer_interrupt(void);
  47 #endif
  48
  49 #define TICK_SIZE       (tick_nsec / 1000)
  50
  51 /*
  52  * Change this if you have some constant time drift
  53  */
  54
  55 /* This is for machines which generate the exact clock. */
  56 #define USECS_PER_JIFFY (1000000/HZ)
  57
  58 static unsigned long latch;
  59
  60 u32 arch_gettimeoffset(void)
  61 {
  62         unsigned long  elapsed_time = 0;  /* [us] */
  63
  64 #if defined(CONFIG_CHIP_M32102) || defined(CONFIG_CHIP_XNUX2) \
  65         || defined(CONFIG_CHIP_VDEC2) || defined(CONFIG_CHIP_M32700) \
  66         || defined(CONFIG_CHIP_OPSP) || defined(CONFIG_CHIP_M32104)
  67 #ifndef CONFIG_SMP
  68
  69         unsigned long count;
  70
  71         /* timer count may underflow right here */
  72         count = inl(M32R_MFT2CUT_PORTL);
  73
  74         if (inl(M32R_ICU_CR18_PORTL) & 0x00000100)      /* underflow check */
  75                 count = 0;
  76
  77         count = (latch - count) * TICK_SIZE;
  78         elapsed_time = (count + latch / 2) / latch;
  79         /* NOTE: LATCH is equal to the "interval" value (= reload count). */
  80
  81 #else /* CONFIG_SMP */
  82         unsigned long count;
  83         static unsigned long p_jiffies = -1;
  84         static unsigned long p_count = 0;
  85
  86         /* timer count may underflow right here */
  87         count = inl(M32R_MFT2CUT_PORTL);
  88
  89         if (jiffies == p_jiffies && count > p_count)
  90                 count = 0;
  91
  92         p_jiffies = jiffies;
  93         p_count = count;
  94
  95         count = (latch - count) * TICK_SIZE;
  96         elapsed_time = (count + latch / 2) / latch;
  97         /* NOTE: LATCH is equal to the "interval" value (= reload count). */
  98 #endif /* CONFIG_SMP */
  99 #elif defined(CONFIG_CHIP_M32310)
 100 #warning do_gettimeoffse not implemented
 101 #else
 102 #error no chip configuration
 103 #endif
 104
 105         return elapsed_time * 1000;
 106 }
 107
 108 /*
 109  * In order to set the CMOS clock precisely, set_rtc_mmss has to be
 110  * called 500 ms after the second nowtime has started, because when
 111  * nowtime is written into the registers of the CMOS clock, it will
 112  * jump to the next second precisely 500 ms later. Check the Motorola
 113  * MC146818A or Dallas DS12887 data sheet for details.
 114  *
 115  * BUG: This routine does not handle hour overflow properly; it just
 116  *      sets the minutes. Usually you won't notice until after reboot!
 117  */
 118 static inline int set_rtc_mmss(unsigned long nowtime)
 119 {
 120         return 0;
 121 }
 122
 123 /* last time the cmos clock got updated */
 124 static long last_rtc_update = 0;
 125
 126 /*
 127  * timer_interrupt() needs to keep up the real-time clock,
 128  * as well as call the "do_timer()" routine every clocktick
 129  */
 130 static irqreturn_t timer_interrupt(int irq, void *dev_id)
 131 {
 132 #ifndef CONFIG_SMP
 133         profile_tick(CPU_PROFILING);
 134 #endif
 135         /* XXX FIXME. Uh, the xtime_lock should be held here, no? */
 136         do_timer(1);
 137
 138 #ifndef CONFIG_SMP
 139         update_process_times(user_mode(get_irq_regs()));
 140 #endif
 141         /*
 142          * If we have an externally synchronized Linux clock, then update
 143          * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
 144          * called as close as possible to 500 ms before the new second starts.
 145          */
 146         write_seqlock(&xtime_lock);
 147         if (ntp_synced()
 148                 && xtime.tv_sec > last_rtc_update + 660
 149                 && (xtime.tv_nsec / 1000) >= 500000 - ((unsigned)TICK_SIZE) / 2
 150                 && (xtime.tv_nsec / 1000) <= 500000 + ((unsigned)TICK_SIZE) / 2)
 151         {
 152                 if (set_rtc_mmss(xtime.tv_sec) == 0)
 153                         last_rtc_update = xtime.tv_sec;
 154                 else    /* do it again in 60 s */
 155                         last_rtc_update = xtime.tv_sec - 600;
 156         }
 157         write_sequnlock(&xtime_lock);
 158         /* As we return to user mode fire off the other CPU schedulers..
 159            this is basically because we don't yet share IRQ's around.
 160            This message is rigged to be safe on the 386 - basically it's
 161            a hack, so don't look closely for now.. */
 162
 163 #ifdef CONFIG_SMP
 164         smp_local_timer_interrupt();
 165         smp_send_timer();
 166 #endif
 167
 168         return IRQ_HANDLED;
 169 }
 170
 171 static struct irqaction irq0 = {
 172         .handler = timer_interrupt,
 173         .flags = IRQF_DISABLED,
 174         .name = "MFT2",
 175 };
 176
 177 void __init time_init(void)
 178 {
 179         unsigned int epoch, year, mon, day, hour, min, sec;
 180
 181         sec = min = hour = day = mon = year = 0;
 182         epoch = 0;
 183
 184         year = 23;
 185         mon = 4;
 186         day = 17;
 187
 188         /* Attempt to guess the epoch.  This is the same heuristic as in rtc.c
 189            so no stupid things will happen to timekeeping.  Who knows, maybe
 190            Ultrix also uses 1952 as epoch ...  */
 191         if (year > 10 && year < 44)
 192                 epoch = 1980;
 193         else if (year < 96)
 194                 epoch = 1952;
 195         year += epoch;
 196
 197         xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
 198         xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
 199         set_normalized_timespec(&wall_to_monotonic,
 200                 -xtime.tv_sec, -xtime.tv_nsec);
 201
 202 #if defined(CONFIG_CHIP_M32102) || defined(CONFIG_CHIP_XNUX2) \
 203         || defined(CONFIG_CHIP_VDEC2) || defined(CONFIG_CHIP_M32700) \
 204         || defined(CONFIG_CHIP_OPSP) || defined(CONFIG_CHIP_M32104)
 205
 206         /* M32102 MFT setup */
 207         setup_irq(M32R_IRQ_MFT2, &irq0);
 208         {
 209                 unsigned long bus_clock;
 210                 unsigned short divide;
 211
 212                 bus_clock = boot_cpu_data.bus_clock;
 213                 divide = boot_cpu_data.timer_divide;
 214                 latch = (bus_clock/divide + HZ / 2) / HZ;
 215
 216                 printk("Timer start : latch = %ld\n", latch);
 217
 218                 outl((M32R_MFTMOD_CC_MASK | M32R_MFTMOD_TCCR \
 219                         |M32R_MFTMOD_CSSEL011), M32R_MFT2MOD_PORTL);
 220                 outl(latch, M32R_MFT2RLD_PORTL);
 221                 outl(latch, M32R_MFT2CUT_PORTL);
 222                 outl(0, M32R_MFT2CMPRLD_PORTL);
 223                 outl((M32R_MFTCR_MFT2MSK|M32R_MFTCR_MFT2EN), M32R_MFTCR_PORTL);
 224         }
 225
 226 #elif defined(CONFIG_CHIP_M32310)
 227 #warning time_init not implemented
 228 #else
 229 #error no chip configuration
 230 #endif
 231 }