arch/mips64/sgi-ip27/ip27-timer.c

   1 /*
   2  * Copytight (C) 1999, 2000 Ralf Baechle (ralf@gnu.org)
   3  * Copytight (C) 1999, 2000 Silicon Graphics, Inc.
   4  */
   5 #include <linux/config.h>
   6 #include <linux/init.h>
   7 #include <linux/kernel.h>
   8 #include <linux/sched.h>
   9 #include <linux/interrupt.h>
  10 #include <linux/kernel_stat.h>
  11 #include <linux/param.h>
  12 #include <linux/timex.h>
  13 #include <linux/mm.h>
  14
  15 #include <asm/pgtable.h>
  16 #include <asm/sgialib.h>
  17 #include <asm/sn/ioc3.h>
  18 #include <asm/m48t35.h>
  19 #include <asm/sn/klconfig.h>
  20 #include <asm/sn/arch.h>
  21 #include <asm/sn/addrs.h>
  22 #include <asm/sn/sn_private.h>
  23 #include <asm/sn/sn0/ip27.h>
  24 #include <asm/sn/sn0/hub.h>
  25
  26 /*
  27  * This is a hack; we really need to figure these values out dynamically
  28  *
  29  * Since 800 ns works very well with various HUB frequencies, such as
  30  * 360, 380, 390 and 400 MHZ, we use 800 ns rtc cycle time.
  31  *
  32  * Ralf: which clock rate is used to feed the counter?
  33  */
  34 #define NSEC_PER_CYCLE          800
  35 #define NSEC_PER_SEC            1000000000
  36 #define CYCLES_PER_SEC          (NSEC_PER_SEC/NSEC_PER_CYCLE)
  37 #define CYCLES_PER_JIFFY        (CYCLES_PER_SEC/HZ)
  38
  39 static unsigned long ct_cur[NR_CPUS];   /* What counter should be at next timer irq */
  40 static long last_rtc_update;            /* Last time the rtc clock got updated */
  41
  42 extern rwlock_t xtime_lock;
  43 extern volatile unsigned long wall_jiffies;
  44
  45
  46 static int set_rtc_mmss(unsigned long nowtime)
  47 {
  48         int retval = 0;
  49         int real_seconds, real_minutes, cmos_minutes;
  50         struct m48t35_rtc *rtc;
  51         nasid_t nid;
  52
  53         nid = get_nasid();
  54         rtc = (struct m48t35_rtc *)(KL_CONFIG_CH_CONS_INFO(nid)->memory_base +
  55                                                         IOC3_BYTEBUS_DEV0);
  56
  57         rtc->control |= M48T35_RTC_READ;
  58         cmos_minutes = rtc->min;
  59         BCD_TO_BIN(cmos_minutes);
  60         rtc->control &= ~M48T35_RTC_READ;
  61
  62         /*
  63          * Since we're only adjusting minutes and seconds, don't interfere with
  64          * hour overflow. This avoids messing with unknown time zones but
  65          * requires your RTC not to be off by more than 15 minutes
  66          */
  67         real_seconds = nowtime % 60;
  68         real_minutes = nowtime / 60;
  69         if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
  70                 real_minutes += 30;     /* correct for half hour time zone */
  71         real_minutes %= 60;
  72
  73         if (abs(real_minutes - cmos_minutes) < 30) {
  74                 BIN_TO_BCD(real_seconds);
  75                 BIN_TO_BCD(real_minutes);
  76                 rtc->control |= M48T35_RTC_SET;
  77                 rtc->sec = real_seconds;
  78                 rtc->min = real_minutes;
  79                 rtc->control &= ~M48T35_RTC_SET;
  80         } else {
  81                 printk(KERN_WARNING
  82                        "set_rtc_mmss: can't update from %d to %d\n",
  83                        cmos_minutes, real_minutes);
  84                 retval = -1;
  85         }
  86
  87         return retval;
  88 }
  89
  90 void rt_timer_interrupt(struct pt_regs *regs)
  91 {
  92         int cpu = smp_processor_id();
  93         int cpuA = ((cputoslice(cpu)) == 0);
  94         int irq = 7;                            /* XXX Assign number */
  95
  96         write_lock(&xtime_lock);
  97
  98 again:
  99         LOCAL_HUB_S(cpuA ? PI_RT_PEND_A : PI_RT_PEND_B, 0);     /* Ack  */
 100         ct_cur[cpu] += CYCLES_PER_JIFFY;
 101         LOCAL_HUB_S(cpuA ? PI_RT_COMPARE_A : PI_RT_COMPARE_B, ct_cur[cpu]);
 102
 103         if (LOCAL_HUB_L(PI_RT_COUNT) >= ct_cur[cpu])
 104                 goto again;
 105
 106         kstat.irqs[cpu][irq]++;         /* kstat only for bootcpu? */
 107
 108         if (cpu == 0)
 109                 do_timer(regs);
 110
 111 #ifdef CONFIG_SMP
 112         {
 113                 int user = user_mode(regs);
 114
 115                 /*
 116                  * update_process_times() expects us to have done irq_enter().
 117                  * Besides, if we don't timer interrupts ignore the global
 118                  * interrupt lock, which is the WrongThing (tm) to do.
 119                  * Picked from i386 code.
 120                  */
 121                 irq_enter(cpu, 0);
 122                 update_process_times(user);
 123                 irq_exit(cpu, 0);
 124         }
 125 #endif /* CONFIG_SMP */
 126
 127         /*
 128          * If we have an externally synchronized Linux clock, then update
 129          * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
 130          * called as close as possible to when a second starts.
 131          */
 132         if ((time_status & STA_UNSYNC) == 0 &&
 133             xtime.tv_sec > last_rtc_update + 660) {
 134                 if (xtime.tv_usec >= 1000000 - ((unsigned) tick) / 2) {
 135                         if (set_rtc_mmss(xtime.tv_sec + 1) == 0)
 136                                 last_rtc_update = xtime.tv_sec;
 137                         else
 138                                 last_rtc_update = xtime.tv_sec - 600;
 139                 } else if (xtime.tv_usec <= ((unsigned) tick) / 2) {
 140                         if (set_rtc_mmss(xtime.tv_sec) == 0)
 141                                 last_rtc_update = xtime.tv_sec;
 142                         else
 143                                 last_rtc_update = xtime.tv_sec - 600;
 144                 }
 145         }
 146
 147         write_unlock(&xtime_lock);
 148 }
 149
 150 unsigned long inline do_gettimeoffset(void)
 151 {
 152         unsigned long ct_cur1;
 153         ct_cur1 = REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT) + CYCLES_PER_JIFFY;
 154         return (ct_cur1 - ct_cur[0]) * NSEC_PER_CYCLE / 1000;
 155 }
 156
 157 void do_gettimeofday(struct timeval *tv)
 158 {
 159         unsigned long flags;
 160         unsigned long usec, sec;
 161
 162         read_lock_irqsave(&xtime_lock, flags);
 163         usec = do_gettimeoffset();
 164         {
 165                 unsigned long lost = jiffies - wall_jiffies;
 166                 if (lost)
 167                         usec += lost * (1000000 / HZ);
 168         }
 169         sec = xtime.tv_sec;
 170         usec += xtime.tv_usec;
 171         read_unlock_irqrestore(&xtime_lock, flags);
 172
 173         while (usec >= 1000000) {
 174                 usec -= 1000000;
 175                 sec++;
 176         }
 177
 178         tv->tv_sec = sec;
 179         tv->tv_usec = usec;
 180 }
 181
 182 void do_settimeofday(struct timeval *tv)
 183 {
 184         write_lock_irq(&xtime_lock);
 185         tv->tv_usec -= do_gettimeoffset();
 186         tv->tv_usec -= (jiffies - wall_jiffies) * (1000000 / HZ);
 187
 188         while (tv->tv_usec < 0) {
 189                 tv->tv_usec += 1000000;
 190                 tv->tv_sec--;
 191         }
 192
 193         xtime = *tv;
 194         time_adjust = 0;                /* stop active adjtime() */
 195         time_status |= STA_UNSYNC;
 196         time_maxerror = NTP_PHASE_LIMIT;
 197         time_esterror = NTP_PHASE_LIMIT;
 198         write_unlock_irq(&xtime_lock);
 199 }
 200
 201 /* Includes for ioc3_init().  */
 202 #include <asm/sn/types.h>
 203 #include <asm/sn/sn0/addrs.h>
 204 #include <asm/sn/sn0/hubni.h>
 205 #include <asm/sn/sn0/hubio.h>
 206 #include <asm/pci/bridge.h>
 207
 208 static __init unsigned long get_m48t35_time(void)
 209 {
 210         unsigned int year, month, date, hour, min, sec;
 211         struct m48t35_rtc *rtc;
 212         nasid_t nid;
 213
 214         nid = get_nasid();
 215         rtc = (struct m48t35_rtc *)(KL_CONFIG_CH_CONS_INFO(nid)->memory_base +
 216                                                         IOC3_BYTEBUS_DEV0);
 217
 218         rtc->control |= M48T35_RTC_READ;
 219         sec = rtc->sec;
 220         min = rtc->min;
 221         hour = rtc->hour;
 222         date = rtc->date;
 223         month = rtc->month;
 224         year = rtc->year;
 225         rtc->control &= ~M48T35_RTC_READ;
 226
 227         BCD_TO_BIN(sec);
 228         BCD_TO_BIN(min);
 229         BCD_TO_BIN(hour);
 230         BCD_TO_BIN(date);
 231         BCD_TO_BIN(month);
 232         BCD_TO_BIN(year);
 233
 234         year += 1970;
 235
 236         return mktime(year, month, date, hour, min, sec);
 237 }
 238
 239 void __init time_init(void)
 240 {
 241         xtime.tv_sec = get_m48t35_time();
 242         xtime.tv_usec = 0;
 243 }
 244
 245 void __init cpu_time_init(void)
 246 {
 247         lboard_t *board;
 248         klcpu_t *cpu;
 249         int cpuid;
 250
 251         /* Don't use ARCS.  ARCS is fragile.  Klconfig is simple and sane.  */
 252         board = find_lboard(KL_CONFIG_INFO(get_nasid()), KLTYPE_IP27);
 253         if (!board)
 254                 panic("Can't find board info for myself.");
 255
 256         cpuid = LOCAL_HUB_L(PI_CPU_NUM) ? IP27_CPU0_INDEX : IP27_CPU1_INDEX;
 257         cpu = (klcpu_t *) KLCF_COMP(board, cpuid);
 258         if (!cpu)
 259                 panic("No information about myself?");
 260
 261         printk("CPU %d clock is %dMHz.\n", smp_processor_id(), cpu->cpu_speed);
 262
 263         set_cp0_status(SRB_TIMOCLK, SRB_TIMOCLK);
 264 }
 265
 266 void __init hub_rtc_init(cnodeid_t cnode)
 267 {
 268         /*
 269          * We only need to initialize the current node.
 270          * If this is not the current node then it is a cpuless
 271          * node and timeouts will not happen there.
 272          */
 273         if (get_compact_nodeid() == cnode) {
 274                 int cpu = smp_processor_id();
 275                 LOCAL_HUB_S(PI_RT_EN_A, 1);
 276                 LOCAL_HUB_S(PI_RT_EN_B, 1);
 277                 LOCAL_HUB_S(PI_PROF_EN_A, 0);
 278                 LOCAL_HUB_S(PI_PROF_EN_B, 0);
 279                 ct_cur[cpu] = CYCLES_PER_JIFFY;
 280                 LOCAL_HUB_S(PI_RT_COMPARE_A, ct_cur[cpu]);
 281                 LOCAL_HUB_S(PI_RT_COUNT, 0);
 282                 LOCAL_HUB_S(PI_RT_PEND_A, 0);
 283                 LOCAL_HUB_S(PI_RT_COMPARE_B, ct_cur[cpu]);
 284                 LOCAL_HUB_S(PI_RT_COUNT, 0);
 285                 LOCAL_HUB_S(PI_RT_PEND_B, 0);
 286         }
 287 }