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

   1 /*
   2  * Copytight (C) 1999, 2000, 05 Ralf Baechle (ralf@linux-mips.org)
   3  * Copytight (C) 1999, 2000 Silicon Graphics, Inc.
   4  */
   5 #include <linux/bcd.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/time.h>
  13 #include <linux/timex.h>
  14 #include <linux/mm.h>
  15
  16 #include <asm/time.h>
  17 #include <asm/pgtable.h>
  18 #include <asm/sgialib.h>
  19 #include <asm/sn/ioc3.h>
  20 #include <asm/m48t35.h>
  21 #include <asm/sn/klconfig.h>
  22 #include <asm/sn/arch.h>
  23 #include <asm/sn/addrs.h>
  24 #include <asm/sn/sn_private.h>
  25 #include <asm/sn/sn0/ip27.h>
  26 #include <asm/sn/sn0/hub.h>
  27
  28 /*
  29  * This is a hack; we really need to figure these values out dynamically
  30  *
  31  * Since 800 ns works very well with various HUB frequencies, such as
  32  * 360, 380, 390 and 400 MHZ, we use 800 ns rtc cycle time.
  33  *
  34  * Ralf: which clock rate is used to feed the counter?
  35  */
  36 #define NSEC_PER_CYCLE          800
  37 #define CYCLES_PER_SEC          (NSEC_PER_SEC/NSEC_PER_CYCLE)
  38 #define CYCLES_PER_JIFFY        (CYCLES_PER_SEC/HZ)
  39
  40 #define TICK_SIZE (tick_nsec / 1000)
  41
  42 static unsigned long ct_cur[NR_CPUS];   /* What counter should be at next timer irq */
  43 static long last_rtc_update;            /* Last time the rtc clock got updated */
  44
  45 extern volatile unsigned long wall_jiffies;
  46
  47 #if 0
  48 static int set_rtc_mmss(unsigned long nowtime)
  49 {
  50         int retval = 0;
  51         int real_seconds, real_minutes, cmos_minutes;
  52         struct m48t35_rtc *rtc;
  53         nasid_t nid;
  54
  55         nid = get_nasid();
  56         rtc = (struct m48t35_rtc *)(KL_CONFIG_CH_CONS_INFO(nid)->memory_base +
  57                                                         IOC3_BYTEBUS_DEV0);
  58
  59         rtc->control |= M48T35_RTC_READ;
  60         cmos_minutes = BCD2BIN(rtc->min);
  61         rtc->control &= ~M48T35_RTC_READ;
  62
  63         /*
  64          * Since we're only adjusting minutes and seconds, don't interfere with
  65          * hour overflow. This avoids messing with unknown time zones but
  66          * requires your RTC not to be off by more than 15 minutes
  67          */
  68         real_seconds = nowtime % 60;
  69         real_minutes = nowtime / 60;
  70         if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
  71                 real_minutes += 30;     /* correct for half hour time zone */
  72         real_minutes %= 60;
  73
  74         if (abs(real_minutes - cmos_minutes) < 30) {
  75                 real_seconds = BIN2BCD(real_seconds);
  76                 real_minutes = BIN2BCD(real_minutes);
  77                 rtc->control |= M48T35_RTC_SET;
  78                 rtc->sec = real_seconds;
  79                 rtc->min = real_minutes;
  80                 rtc->control &= ~M48T35_RTC_SET;
  81         } else {
  82                 printk(KERN_WARNING
  83                        "set_rtc_mmss: can't update from %d to %d\n",
  84                        cmos_minutes, real_minutes);
  85                 retval = -1;
  86         }
  87
  88         return retval;
  89 }
  90 #endif
  91
  92 static unsigned int rt_timer_irq;
  93
  94 void ip27_rt_timer_interrupt(struct pt_regs *regs)
  95 {
  96         int cpu = smp_processor_id();
  97         int cpuA = cputoslice(cpu) == 0;
  98         unsigned int irq = rt_timer_irq;
  99
 100         irq_enter();
 101         write_seqlock(&xtime_lock);
 102
 103 again:
 104         LOCAL_HUB_S(cpuA ? PI_RT_PEND_A : PI_RT_PEND_B, 0);     /* Ack  */
 105         ct_cur[cpu] += CYCLES_PER_JIFFY;
 106         LOCAL_HUB_S(cpuA ? PI_RT_COMPARE_A : PI_RT_COMPARE_B, ct_cur[cpu]);
 107
 108         if (LOCAL_HUB_L(PI_RT_COUNT) >= ct_cur[cpu])
 109                 goto again;
 110
 111         kstat_this_cpu.irqs[irq]++;             /* kstat only for bootcpu? */
 112
 113         if (cpu == 0)
 114                 do_timer(regs);
 115
 116         update_process_times(user_mode(regs));
 117
 118         /*
 119          * If we have an externally synchronized Linux clock, then update
 120          * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
 121          * called as close as possible to when a second starts.
 122          */
 123         if (ntp_synced() &&
 124             xtime.tv_sec > last_rtc_update + 660 &&
 125             (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
 126             (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
 127                 if (rtc_mips_set_time(xtime.tv_sec) == 0) {
 128                         last_rtc_update = xtime.tv_sec;
 129                 } else {
 130                         last_rtc_update = xtime.tv_sec - 600;
 131                         /* do it again in 60 s */
 132                 }
 133         }
 134
 135         write_sequnlock(&xtime_lock);
 136         irq_exit();
 137 }
 138
 139 unsigned long ip27_do_gettimeoffset(void)
 140 {
 141         unsigned long ct_cur1;
 142         ct_cur1 = REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT) + CYCLES_PER_JIFFY;
 143         return (ct_cur1 - ct_cur[0]) * NSEC_PER_CYCLE / 1000;
 144 }
 145
 146 /* Includes for ioc3_init().  */
 147 #include <asm/sn/types.h>
 148 #include <asm/sn/sn0/addrs.h>
 149 #include <asm/sn/sn0/hubni.h>
 150 #include <asm/sn/sn0/hubio.h>
 151 #include <asm/pci/bridge.h>
 152
 153 static __init unsigned long get_m48t35_time(void)
 154 {
 155         unsigned int year, month, date, hour, min, sec;
 156         struct m48t35_rtc *rtc;
 157         nasid_t nid;
 158
 159         nid = get_nasid();
 160         rtc = (struct m48t35_rtc *)(KL_CONFIG_CH_CONS_INFO(nid)->memory_base +
 161                                                         IOC3_BYTEBUS_DEV0);
 162
 163         rtc->control |= M48T35_RTC_READ;
 164         sec = rtc->sec;
 165         min = rtc->min;
 166         hour = rtc->hour;
 167         date = rtc->date;
 168         month = rtc->month;
 169         year = rtc->year;
 170         rtc->control &= ~M48T35_RTC_READ;
 171
 172         sec = BCD2BIN(sec);
 173         min = BCD2BIN(min);
 174         hour = BCD2BIN(hour);
 175         date = BCD2BIN(date);
 176         month = BCD2BIN(month);
 177         year = BCD2BIN(year);
 178
 179         year += 1970;
 180
 181         return mktime(year, month, date, hour, min, sec);
 182 }
 183
 184 static void startup_rt_irq(unsigned int irq)
 185 {
 186 }
 187
 188 static void shutdown_rt_irq(unsigned int irq)
 189 {
 190 }
 191
 192 static void enable_rt_irq(unsigned int irq)
 193 {
 194 }
 195
 196 static void disable_rt_irq(unsigned int irq)
 197 {
 198 }
 199
 200 static void mask_and_ack_rt(unsigned int irq)
 201 {
 202 }
 203
 204 static void end_rt_irq(unsigned int irq)
 205 {
 206 }
 207
 208 static struct irq_chip rt_irq_type = {
 209         .typename       = "SN HUB RT timer",
 210         .startup        = startup_rt_irq,
 211         .shutdown       = shutdown_rt_irq,
 212         .enable         = enable_rt_irq,
 213         .disable        = disable_rt_irq,
 214         .ack            = mask_and_ack_rt,
 215         .end            = end_rt_irq,
 216 };
 217
 218 static struct irqaction rt_irqaction = {
 219         .handler        = ip27_rt_timer_interrupt,
 220         .flags          = IRQF_DISABLED,
 221         .mask           = CPU_MASK_NONE,
 222         .name           = "timer"
 223 };
 224
 225 extern int allocate_irqno(void);
 226
 227 static void ip27_timer_setup(struct irqaction *irq)
 228 {
 229         int irqno  = allocate_irqno();
 230
 231         if (irqno < 0)
 232                 panic("Can't allocate interrupt number for timer interrupt");
 233
 234         irq_desc[irqno].status = IRQ_DISABLED;
 235         irq_desc[irqno].action = NULL;
 236         irq_desc[irqno].depth = 1;
 237         irq_desc[irqno].chip = &rt_irq_type;
 238
 239         /* over-write the handler, we use our own way */
 240         irq->handler = no_action;
 241
 242         /* setup irqaction */
 243         irq_desc[irqno].status |= IRQ_PER_CPU;
 244
 245         rt_timer_irq = irqno;
 246 }
 247
 248 void __init ip27_time_init(void)
 249 {
 250         xtime.tv_sec = get_m48t35_time();
 251         xtime.tv_nsec = 0;
 252
 253         do_gettimeoffset = ip27_do_gettimeoffset;
 254
 255         board_timer_setup = ip27_timer_setup;
 256 }
 257
 258 void __init cpu_time_init(void)
 259 {
 260         lboard_t *board;
 261         klcpu_t *cpu;
 262         int cpuid;
 263
 264         /* Don't use ARCS.  ARCS is fragile.  Klconfig is simple and sane.  */
 265         board = find_lboard(KL_CONFIG_INFO(get_nasid()), KLTYPE_IP27);
 266         if (!board)
 267                 panic("Can't find board info for myself.");
 268
 269         cpuid = LOCAL_HUB_L(PI_CPU_NUM) ? IP27_CPU0_INDEX : IP27_CPU1_INDEX;
 270         cpu = (klcpu_t *) KLCF_COMP(board, cpuid);
 271         if (!cpu)
 272                 panic("No information about myself?");
 273
 274         printk("CPU %d clock is %dMHz.\n", smp_processor_id(), cpu->cpu_speed);
 275
 276         set_c0_status(SRB_TIMOCLK);
 277 }
 278
 279 void __init hub_rtc_init(cnodeid_t cnode)
 280 {
 281         /*
 282          * We only need to initialize the current node.
 283          * If this is not the current node then it is a cpuless
 284          * node and timeouts will not happen there.
 285          */
 286         if (get_compact_nodeid() == cnode) {
 287                 int cpu = smp_processor_id();
 288                 LOCAL_HUB_S(PI_RT_EN_A, 1);
 289                 LOCAL_HUB_S(PI_RT_EN_B, 1);
 290                 LOCAL_HUB_S(PI_PROF_EN_A, 0);
 291                 LOCAL_HUB_S(PI_PROF_EN_B, 0);
 292                 ct_cur[cpu] = CYCLES_PER_JIFFY;
 293                 LOCAL_HUB_S(PI_RT_COMPARE_A, ct_cur[cpu]);
 294                 LOCAL_HUB_S(PI_RT_COUNT, 0);
 295                 LOCAL_HUB_S(PI_RT_PEND_A, 0);
 296                 LOCAL_HUB_S(PI_RT_COMPARE_B, ct_cur[cpu]);
 297                 LOCAL_HUB_S(PI_RT_COUNT, 0);
 298                 LOCAL_HUB_S(PI_RT_PEND_B, 0);
 299         }
 300 }