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 static u32 m32r_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 = DIV_ROUND_CLOSEST(count, 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 = DIV_ROUND_CLOSEST(count, 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  * timer_interrupt() needs to keep up the real-time clock,
 110  * as well as call the "xtime_update()" routine every clocktick
 111  */
 112 static irqreturn_t timer_interrupt(int irq, void *dev_id)
 113 {
 114 #ifndef CONFIG_SMP
 115         profile_tick(CPU_PROFILING);
 116 #endif
 117         xtime_update(1);
 118
 119 #ifndef CONFIG_SMP
 120         update_process_times(user_mode(get_irq_regs()));
 121 #endif
 122         /* As we return to user mode fire off the other CPU schedulers..
 123            this is basically because we don't yet share IRQ's around.
 124            This message is rigged to be safe on the 386 - basically it's
 125            a hack, so don't look closely for now.. */
 126
 127 #ifdef CONFIG_SMP
 128         smp_local_timer_interrupt();
 129         smp_send_timer();
 130 #endif
 131
 132         return IRQ_HANDLED;
 133 }
 134
 135 static struct irqaction irq0 = {
 136         .handler = timer_interrupt,
 137         .name = "MFT2",
 138 };
 139
 140 void read_persistent_clock(struct timespec *ts)
 141 {
 142         unsigned int epoch, year, mon, day, hour, min, sec;
 143
 144         sec = min = hour = day = mon = year = 0;
 145         epoch = 0;
 146
 147         year = 23;
 148         mon = 4;
 149         day = 17;
 150
 151         /* Attempt to guess the epoch.  This is the same heuristic as in rtc.c
 152            so no stupid things will happen to timekeeping.  Who knows, maybe
 153            Ultrix also uses 1952 as epoch ...  */
 154         if (year > 10 && year < 44)
 155                 epoch = 1980;
 156         else if (year < 96)
 157                 epoch = 1952;
 158         year += epoch;
 159
 160         ts->tv_sec = mktime(year, mon, day, hour, min, sec);
 161         ts->tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
 162 }
 163
 164
 165 void __init time_init(void)
 166 {
 167         arch_gettimeoffset = m32r_gettimeoffset;
 168
 169 #if defined(CONFIG_CHIP_M32102) || defined(CONFIG_CHIP_XNUX2) \
 170         || defined(CONFIG_CHIP_VDEC2) || defined(CONFIG_CHIP_M32700) \
 171         || defined(CONFIG_CHIP_OPSP) || defined(CONFIG_CHIP_M32104)
 172
 173         /* M32102 MFT setup */
 174         setup_irq(M32R_IRQ_MFT2, &irq0);
 175         {
 176                 unsigned long bus_clock;
 177                 unsigned short divide;
 178
 179                 bus_clock = boot_cpu_data.bus_clock;
 180                 divide = boot_cpu_data.timer_divide;
 181                 latch = DIV_ROUND_CLOSEST(bus_clock/divide, HZ);
 182
 183                 printk("Timer start : latch = %ld\n", latch);
 184
 185                 outl((M32R_MFTMOD_CC_MASK | M32R_MFTMOD_TCCR \
 186                         |M32R_MFTMOD_CSSEL011), M32R_MFT2MOD_PORTL);
 187                 outl(latch, M32R_MFT2RLD_PORTL);
 188                 outl(latch, M32R_MFT2CUT_PORTL);
 189                 outl(0, M32R_MFT2CMPRLD_PORTL);
 190                 outl((M32R_MFTCR_MFT2MSK|M32R_MFTCR_MFT2EN), M32R_MFTCR_PORTL);
 191         }
 192
 193 #elif defined(CONFIG_CHIP_M32310)
 194 #warning time_init not implemented
 195 #else
 196 #error no chip configuration
 197 #endif
 198 }