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

   1 /*
   2  * Copytight (C) 1999, 2000, 05, 06 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 #if 0
  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 = BCD2BIN(rtc->min);
  59         rtc->control &= ~M48T35_RTC_READ;
  60
  61         /*
  62          * Since we're only adjusting minutes and seconds, don't interfere with
  63          * hour overflow. This avoids messing with unknown time zones but
  64          * requires your RTC not to be off by more than 15 minutes
  65          */
  66         real_seconds = nowtime % 60;
  67         real_minutes = nowtime / 60;
  68         if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
  69                 real_minutes += 30;     /* correct for half hour time zone */
  70         real_minutes %= 60;
  71
  72         if (abs(real_minutes - cmos_minutes) < 30) {
  73                 real_seconds = BIN2BCD(real_seconds);
  74                 real_minutes = BIN2BCD(real_minutes);
  75                 rtc->control |= M48T35_RTC_SET;
  76                 rtc->sec = real_seconds;
  77                 rtc->min = real_minutes;
  78                 rtc->control &= ~M48T35_RTC_SET;
  79         } else {
  80                 printk(KERN_WARNING
  81                        "set_rtc_mmss: can't update from %d to %d\n",
  82                        cmos_minutes, real_minutes);
  83                 retval = -1;
  84         }
  85
  86         return retval;
  87 }
  88 #endif
  89
  90 static unsigned int rt_timer_irq;
  91
  92 void ip27_rt_timer_interrupt(void)
  93 {
  94         int cpu = smp_processor_id();
  95         int cpuA = cputoslice(cpu) == 0;
  96         unsigned int irq = rt_timer_irq;
  97
  98         irq_enter();
  99         write_seqlock(&xtime_lock);
 100
 101 again:
 102         LOCAL_HUB_S(cpuA ? PI_RT_PEND_A : PI_RT_PEND_B, 0);     /* Ack  */
 103         ct_cur[cpu] += CYCLES_PER_JIFFY;
 104         LOCAL_HUB_S(cpuA ? PI_RT_COMPARE_A : PI_RT_COMPARE_B, ct_cur[cpu]);
 105
 106         if (LOCAL_HUB_L(PI_RT_COUNT) >= ct_cur[cpu])
 107                 goto again;
 108
 109         kstat_this_cpu.irqs[irq]++;             /* kstat only for bootcpu? */
 110
 111         if (cpu == 0)
 112                 do_timer(1);
 113
 114         update_process_times(user_mode(get_irq_regs()));
 115
 116         /*
 117          * If we have an externally synchronized Linux clock, then update
 118          * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
 119          * called as close as possible to when a second starts.
 120          */
 121         if (ntp_synced() &&
 122             xtime.tv_sec > last_rtc_update + 660 &&
 123             (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
 124             (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
 125                 if (rtc_mips_set_time(xtime.tv_sec) == 0) {
 126                         last_rtc_update = xtime.tv_sec;
 127                 } else {
 128                         last_rtc_update = xtime.tv_sec - 600;
 129                         /* do it again in 60 s */
 130                 }
 131         }
 132
 133         write_sequnlock(&xtime_lock);
 134         irq_exit();
 135 }
 136
 137 /* Includes for ioc3_init().  */
 138 #include <asm/sn/types.h>
 139 #include <asm/sn/sn0/addrs.h>
 140 #include <asm/sn/sn0/hubni.h>
 141 #include <asm/sn/sn0/hubio.h>
 142 #include <asm/pci/bridge.h>
 143
 144 static __init unsigned long get_m48t35_time(void)
 145 {
 146         unsigned int year, month, date, hour, min, sec;
 147         struct m48t35_rtc *rtc;
 148         nasid_t nid;
 149
 150         nid = get_nasid();
 151         rtc = (struct m48t35_rtc *)(KL_CONFIG_CH_CONS_INFO(nid)->memory_base +
 152                                                         IOC3_BYTEBUS_DEV0);
 153
 154         rtc->control |= M48T35_RTC_READ;
 155         sec = rtc->sec;
 156         min = rtc->min;
 157         hour = rtc->hour;
 158         date = rtc->date;
 159         month = rtc->month;
 160         year = rtc->year;
 161         rtc->control &= ~M48T35_RTC_READ;
 162
 163         sec = BCD2BIN(sec);
 164         min = BCD2BIN(min);
 165         hour = BCD2BIN(hour);
 166         date = BCD2BIN(date);
 167         month = BCD2BIN(month);
 168         year = BCD2BIN(year);
 169
 170         year += 1970;
 171
 172         return mktime(year, month, date, hour, min, sec);
 173 }
 174
 175 static void enable_rt_irq(unsigned int irq)
 176 {
 177 }
 178
 179 static void disable_rt_irq(unsigned int irq)
 180 {
 181 }
 182
 183 static struct irq_chip rt_irq_type = {
 184         .name           = "SN HUB RT timer",
 185         .ack            = disable_rt_irq,
 186         .mask           = disable_rt_irq,
 187         .mask_ack       = disable_rt_irq,
 188         .unmask         = enable_rt_irq,
 189         .eoi            = enable_rt_irq,
 190 };
 191
 192 static struct irqaction rt_irqaction = {
 193         .handler        = (irq_handler_t) ip27_rt_timer_interrupt,
 194         .flags          = IRQF_DISABLED,
 195         .mask           = CPU_MASK_NONE,
 196         .name           = "timer"
 197 };
 198
 199 void __init plat_timer_setup(struct irqaction *irq)
 200 {
 201         int irqno  = allocate_irqno();
 202
 203         if (irqno < 0)
 204                 panic("Can't allocate interrupt number for timer interrupt");
 205
 206         set_irq_chip_and_handler(irqno, &rt_irq_type, handle_percpu_irq);
 207
 208         /* over-write the handler, we use our own way */
 209         irq->handler = no_action;
 210
 211         /* setup irqaction */
 212         irq_desc[irqno].status |= IRQ_PER_CPU;
 213
 214         rt_timer_irq = irqno;
 215         /*
 216          * Only needed to get /proc/interrupt to display timer irq stats
 217          */
 218         setup_irq(irqno, &rt_irqaction);
 219 }
 220
 221 static cycle_t ip27_hpt_read(void)
 222 {
 223         return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
 224 }
 225
 226 void __init ip27_time_init(void)
 227 {
 228         clocksource_mips.read = ip27_hpt_read;
 229         mips_hpt_frequency = CYCLES_PER_SEC;
 230         xtime.tv_sec = get_m48t35_time();
 231         xtime.tv_nsec = 0;
 232 }
 233
 234 void __init cpu_time_init(void)
 235 {
 236         lboard_t *board;
 237         klcpu_t *cpu;
 238         int cpuid;
 239
 240         /* Don't use ARCS.  ARCS is fragile.  Klconfig is simple and sane.  */
 241         board = find_lboard(KL_CONFIG_INFO(get_nasid()), KLTYPE_IP27);
 242         if (!board)
 243                 panic("Can't find board info for myself.");
 244
 245         cpuid = LOCAL_HUB_L(PI_CPU_NUM) ? IP27_CPU0_INDEX : IP27_CPU1_INDEX;
 246         cpu = (klcpu_t *) KLCF_COMP(board, cpuid);
 247         if (!cpu)
 248                 panic("No information about myself?");
 249
 250         printk("CPU %d clock is %dMHz.\n", smp_processor_id(), cpu->cpu_speed);
 251
 252         set_c0_status(SRB_TIMOCLK);
 253 }
 254
 255 void __init hub_rtc_init(cnodeid_t cnode)
 256 {
 257         /*
 258          * We only need to initialize the current node.
 259          * If this is not the current node then it is a cpuless
 260          * node and timeouts will not happen there.
 261          */
 262         if (get_compact_nodeid() == cnode) {
 263                 int cpu = smp_processor_id();
 264                 LOCAL_HUB_S(PI_RT_EN_A, 1);
 265                 LOCAL_HUB_S(PI_RT_EN_B, 1);
 266                 LOCAL_HUB_S(PI_PROF_EN_A, 0);
 267                 LOCAL_HUB_S(PI_PROF_EN_B, 0);
 268                 ct_cur[cpu] = CYCLES_PER_JIFFY;
 269                 LOCAL_HUB_S(PI_RT_COMPARE_A, ct_cur[cpu]);
 270                 LOCAL_HUB_S(PI_RT_COUNT, 0);
 271                 LOCAL_HUB_S(PI_RT_PEND_A, 0);
 272                 LOCAL_HUB_S(PI_RT_COMPARE_B, ct_cur[cpu]);
 273                 LOCAL_HUB_S(PI_RT_COUNT, 0);
 274                 LOCAL_HUB_S(PI_RT_PEND_B, 0);
 275         }
 276 }