text: /*
   * Copytight (C) 1999, 2000, 05 Ralf Baechle (ralf@linux-mips.org)
   * Copytight (C) 1999, 2000 Silicon Graphics, Inc.
   */
  #include <linux/bcd.h>
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/sched.h>
  #include <linux/interrupt.h>
  #include <linux/kernel_stat.h>
  #include <linux/param.h>
  #include <linux/time.h>
  #include <linux/timex.h>
  #include <linux/mm.h>
  
  #include <asm/time.h>
  #include <asm/pgtable.h>
  #include <asm/sgialib.h>
  #include <asm/sn/ioc3.h>
  #include <asm/m48t35.h>
  #include <asm/sn/klconfig.h>
  #include <asm/sn/arch.h>
  #include <asm/sn/addrs.h>
  #include <asm/sn/sn_private.h>
  #include <asm/sn/sn0/ip27.h>
  #include <asm/sn/sn0/hub.h>
  
  /*
   * This is a hack; we really need to figure these values out dynamically
   *
   * Since 800 ns works very well with various HUB frequencies, such as
   * 360, 380, 390 and 400 MHZ, we use 800 ns rtc cycle time.
   *
   * Ralf: which clock rate is used to feed the counter?
   */
  #define NSEC_PER_CYCLE		800
  #define CYCLES_PER_SEC		(NSEC_PER_SEC/NSEC_PER_CYCLE)
  #define CYCLES_PER_JIFFY	(CYCLES_PER_SEC/HZ)
  
  #define TICK_SIZE (tick_nsec / 1000)
  
  static unsigned long ct_cur[NR_CPUS];	/* What counter should be at next timer irq */
  static long last_rtc_update;		/* Last time the rtc clock got updated */
  
  extern volatile unsigned long wall_jiffies;
  
  #if 0
  static int set_rtc_mmss(unsigned long nowtime)
  {
  	int retval = 0;
  	int real_seconds, real_minutes, cmos_minutes;
  	struct m48t35_rtc *rtc;
  	nasid_t nid;
  
  	nid = get_nasid();
  	rtc = (struct m48t35_rtc *)(KL_CONFIG_CH_CONS_INFO(nid)->memory_base +
  							IOC3_BYTEBUS_DEV0);
  
  	rtc->control |= M48T35_RTC_READ;
  	cmos_minutes = BCD2BIN(rtc->min);
  	rtc->control &= ~M48T35_RTC_READ;
  
  	/*
  	 * Since we're only adjusting minutes and seconds, don't interfere with
  	 * hour overflow. This avoids messing with unknown time zones but
  	 * requires your RTC not to be off by more than 15 minutes
  	 */
  	real_seconds = nowtime % 60;
  	real_minutes = nowtime / 60;
  	if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
  		real_minutes += 30;	/* correct for half hour time zone */
  	real_minutes %= 60;
  
  	if (abs(real_minutes - cmos_minutes) < 30) {
  		real_seconds = BIN2BCD(real_seconds);
  		real_minutes = BIN2BCD(real_minutes);
  		rtc->control |= M48T35_RTC_SET;
  		rtc->sec = real_seconds;
  		rtc->min = real_minutes;
  		rtc->control &= ~M48T35_RTC_SET;
  	} else {
  		printk(KERN_WARNING
  		       "set_rtc_mmss: can't update from %d to %d\n",
  		       cmos_minutes, real_minutes);
  		retval = -1;
  	}
  
  	return retval;
  }
  #endif
  
  void ip27_rt_timer_interrupt(struct pt_regs *regs)
  {
  	int cpu = smp_processor_id();
  	int cpuA = cputoslice(cpu) == 0;
  	int irq = 9;				/* XXX Assign number */
  
  	irq_enter();
  	write_seqlock(&xtime_lock);
  
  again:
  	LOCAL_HUB_S(cpuA ? PI_RT_PEND_A : PI_RT_PEND_B, 0);	/* Ack  */
  	ct_cur[cpu] += CYCLES_PER_JIFFY;
  	LOCAL_HUB_S(cpuA ? PI_RT_COMPARE_A : PI_RT_COMPARE_B, ct_cur[cpu]);
  
  	if (LOCAL_HUB_L(PI_RT_COUNT) >= ct_cur[cpu])
  		goto again;
  
  	kstat_this_cpu.irqs[irq]++;		/* kstat only for bootcpu? */
  
  	if (cpu == 0)
  		do_timer(regs);
  
  	update_process_times(user_mode(regs));
  
  	/*
  	 * If we have an externally synchronized Linux clock, then update
  	 * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
  	 * called as close as possible to when a second starts.
  	 */
  	if (ntp_synced() &&
  	    xtime.tv_sec > last_rtc_update + 660 &&
  	    (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
  	    (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
  		if (rtc_set_time(xtime.tv_sec) == 0) {
  			last_rtc_update = xtime.tv_sec;
  		} else {
  			last_rtc_update = xtime.tv_sec - 600;
  			/* do it again in 60 s */
  		}
  	}
  
  	write_sequnlock(&xtime_lock);
  	irq_exit();
  }
  
  unsigned long ip27_do_gettimeoffset(void)
  {
  	unsigned long ct_cur1;
  	ct_cur1 = REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT) + CYCLES_PER_JIFFY;
  	return (ct_cur1 - ct_cur[0]) * NSEC_PER_CYCLE / 1000;
  }
  
  /* Includes for ioc3_init().  */
  #include <asm/sn/types.h>
  #include <asm/sn/sn0/addrs.h>
  #include <asm/sn/sn0/hubni.h>
  #include <asm/sn/sn0/hubio.h>
  #include <asm/pci/bridge.h>
  
  static __init unsigned long get_m48t35_time(void)
  {
          unsigned int year, month, date, hour, min, sec;
  	struct m48t35_rtc *rtc;
  	nasid_t nid;
  
  	nid = get_nasid();
  	rtc = (struct m48t35_rtc *)(KL_CONFIG_CH_CONS_INFO(nid)->memory_base +
  							IOC3_BYTEBUS_DEV0);
  
  	rtc->control |= M48T35_RTC_READ;
  	sec = rtc->sec;
  	min = rtc->min;
  	hour = rtc->hour;
  	date = rtc->date;
  	month = rtc->month;
  	year = rtc->year;
  	rtc->control &= ~M48T35_RTC_READ;
  
          sec = BCD2BIN(sec);
          min = BCD2BIN(min);
          hour = BCD2BIN(hour);
          date = BCD2BIN(date);
          month = BCD2BIN(month);
          year = BCD2BIN(year);
  
          year += 1970;
  
          return mktime(year, month, date, hour, min, sec);
  }
  
  static void ip27_timer_setup(struct irqaction *irq)
  {
  	/* over-write the handler, we use our own way */
  	irq->handler = no_action;
  
  	/* setup irqaction */
  //	setup_irq(IP27_TIMER_IRQ, irq);		/* XXX Can't do this yet.  */
  }
  
  void __init ip27_time_init(void)
  {
  	xtime.tv_sec = get_m48t35_time();
  	xtime.tv_nsec = 0;
  
  	do_gettimeoffset = ip27_do_gettimeoffset;
  
  	board_timer_setup = ip27_timer_setup;
  }
  
  void __init cpu_time_init(void)
  {
  	lboard_t *board;
  	klcpu_t *cpu;
  	int cpuid;
  
  	/* Don't use ARCS.  ARCS is fragile.  Klconfig is simple and sane.  */
  	board = find_lboard(KL_CONFIG_INFO(get_nasid()), KLTYPE_IP27);
  	if (!board)
  		panic("Can't find board info for myself.");
  
  	cpuid = LOCAL_HUB_L(PI_CPU_NUM) ? IP27_CPU0_INDEX : IP27_CPU1_INDEX;
  	cpu = (klcpu_t *) KLCF_COMP(board, cpuid);
  	if (!cpu)
  		panic("No information about myself?");
  
  	printk("CPU %d clock is %dMHz.\n", smp_processor_id(), cpu->cpu_speed);
  
  	set_c0_status(SRB_TIMOCLK);
  }
  
  void __init hub_rtc_init(cnodeid_t cnode)
  {
  	/*
  	 * We only need to initialize the current node.
  	 * If this is not the current node then it is a cpuless
  	 * node and timeouts will not happen there.
  	 */
  	if (get_compact_nodeid() == cnode) {
  		int cpu = smp_processor_id();
  		LOCAL_HUB_S(PI_RT_EN_A, 1);
  		LOCAL_HUB_S(PI_RT_EN_B, 1);
  		LOCAL_HUB_S(PI_PROF_EN_A, 0);
  		LOCAL_HUB_S(PI_PROF_EN_B, 0);
  		ct_cur[cpu] = CYCLES_PER_JIFFY;
  		LOCAL_HUB_S(PI_RT_COMPARE_A, ct_cur[cpu]);
  		LOCAL_HUB_S(PI_RT_COUNT, 0);
  		LOCAL_HUB_S(PI_RT_PEND_A, 0);
  		LOCAL_HUB_S(PI_RT_COMPARE_B, ct_cur[cpu]);
  		LOCAL_HUB_S(PI_RT_COUNT, 0);
  		LOCAL_HUB_S(PI_RT_PEND_B, 0);
  	}
  }
  