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/clockchips.h>
   7 #include <linux/init.h>
   8 #include <linux/kernel.h>
   9 #include <linux/sched.h>
  10 #include <linux/interrupt.h>
  11 #include <linux/kernel_stat.h>
  12 #include <linux/param.h>
  13 #include <linux/smp.h>
  14 #include <linux/time.h>
  15 #include <linux/timex.h>
  16 #include <linux/mm.h>
  17 #include <linux/platform_device.h>
  18
  19 #include <asm/time.h>
  20 #include <asm/pgtable.h>
  21 #include <asm/sgialib.h>
  22 #include <asm/sn/ioc3.h>
  23 #include <asm/sn/klconfig.h>
  24 #include <asm/sn/arch.h>
  25 #include <asm/sn/addrs.h>
  26 #include <asm/sn/sn_private.h>
  27 #include <asm/sn/sn0/ip27.h>
  28 #include <asm/sn/sn0/hub.h>
  29
  30 #define TICK_SIZE (tick_nsec / 1000)
  31
  32 /* Includes for ioc3_init().  */
  33 #include <asm/sn/types.h>
  34 #include <asm/sn/sn0/addrs.h>
  35 #include <asm/sn/sn0/hubni.h>
  36 #include <asm/sn/sn0/hubio.h>
  37 #include <asm/pci/bridge.h>
  38
  39 static void enable_rt_irq(struct irq_data *d)
  40 {
  41 }
  42
  43 static void disable_rt_irq(struct irq_data *d)
  44 {
  45 }
  46
  47 static struct irq_chip rt_irq_type = {
  48         .name           = "SN HUB RT timer",
  49         .irq_mask       = disable_rt_irq,
  50         .irq_unmask     = enable_rt_irq,
  51 };
  52
  53 static int rt_next_event(unsigned long delta, struct clock_event_device *evt)
  54 {
  55         unsigned int cpu = smp_processor_id();
  56         int slice = cputoslice(cpu);
  57         unsigned long cnt;
  58
  59         cnt = LOCAL_HUB_L(PI_RT_COUNT);
  60         cnt += delta;
  61         LOCAL_HUB_S(PI_RT_COMPARE_A + PI_COUNT_OFFSET * slice, cnt);
  62
  63         return LOCAL_HUB_L(PI_RT_COUNT) >= cnt ? -ETIME : 0;
  64 }
  65
  66 static void rt_set_mode(enum clock_event_mode mode,
  67                 struct clock_event_device *evt)
  68 {
  69         switch (mode) {
  70         case CLOCK_EVT_MODE_ONESHOT:
  71                 /* The only mode supported */
  72                 break;
  73
  74         case CLOCK_EVT_MODE_PERIODIC:
  75         case CLOCK_EVT_MODE_UNUSED:
  76         case CLOCK_EVT_MODE_SHUTDOWN:
  77         case CLOCK_EVT_MODE_RESUME:
  78                 /* Nothing to do  */
  79                 break;
  80         }
  81 }
  82
  83 int rt_timer_irq;
  84
  85 static DEFINE_PER_CPU(struct clock_event_device, hub_rt_clockevent);
  86 static DEFINE_PER_CPU(char [11], hub_rt_name);
  87
  88 static irqreturn_t hub_rt_counter_handler(int irq, void *dev_id)
  89 {
  90         unsigned int cpu = smp_processor_id();
  91         struct clock_event_device *cd = &per_cpu(hub_rt_clockevent, cpu);
  92         int slice = cputoslice(cpu);
  93
  94         /*
  95          * Ack
  96          */
  97         LOCAL_HUB_S(PI_RT_PEND_A + PI_COUNT_OFFSET * slice, 0);
  98         cd->event_handler(cd);
  99
 100         return IRQ_HANDLED;
 101 }
 102
 103 struct irqaction hub_rt_irqaction = {
 104         .handler        = hub_rt_counter_handler,
 105         .flags          = IRQF_DISABLED | IRQF_PERCPU | IRQF_TIMER,
 106         .name           = "hub-rt",
 107 };
 108
 109 /*
 110  * This is a hack; we really need to figure these values out dynamically
 111  *
 112  * Since 800 ns works very well with various HUB frequencies, such as
 113  * 360, 380, 390 and 400 MHZ, we use 800 ns rtc cycle time.
 114  *
 115  * Ralf: which clock rate is used to feed the counter?
 116  */
 117 #define NSEC_PER_CYCLE          800
 118 #define CYCLES_PER_SEC          (NSEC_PER_SEC / NSEC_PER_CYCLE)
 119
 120 void __cpuinit hub_rt_clock_event_init(void)
 121 {
 122         unsigned int cpu = smp_processor_id();
 123         struct clock_event_device *cd = &per_cpu(hub_rt_clockevent, cpu);
 124         unsigned char *name = per_cpu(hub_rt_name, cpu);
 125         int irq = rt_timer_irq;
 126
 127         sprintf(name, "hub-rt %d", cpu);
 128         cd->name                = name;
 129         cd->features            = CLOCK_EVT_FEAT_ONESHOT;
 130         clockevent_set_clock(cd, CYCLES_PER_SEC);
 131         cd->max_delta_ns        = clockevent_delta2ns(0xfffffffffffff, cd);
 132         cd->min_delta_ns        = clockevent_delta2ns(0x300, cd);
 133         cd->rating              = 200;
 134         cd->irq                 = irq;
 135         cd->cpumask             = cpumask_of(cpu);
 136         cd->set_next_event      = rt_next_event;
 137         cd->set_mode            = rt_set_mode;
 138         clockevents_register_device(cd);
 139 }
 140
 141 static void __init hub_rt_clock_event_global_init(void)
 142 {
 143         int irq;
 144
 145         do {
 146                 smp_wmb();
 147                 irq = rt_timer_irq;
 148                 if (irq)
 149                         break;
 150
 151                 irq = allocate_irqno();
 152                 if (irq < 0)
 153                         panic("Allocation of irq number for timer failed");
 154         } while (xchg(&rt_timer_irq, irq));
 155
 156         irq_set_chip_and_handler(irq, &rt_irq_type, handle_percpu_irq);
 157         setup_irq(irq, &hub_rt_irqaction);
 158 }
 159
 160 static cycle_t hub_rt_read(struct clocksource *cs)
 161 {
 162         return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
 163 }
 164
 165 struct clocksource hub_rt_clocksource = {
 166         .name   = "HUB-RT",
 167         .rating = 200,
 168         .read   = hub_rt_read,
 169         .mask   = CLOCKSOURCE_MASK(52),
 170         .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
 171 };
 172
 173 static void __init hub_rt_clocksource_init(void)
 174 {
 175         struct clocksource *cs = &hub_rt_clocksource;
 176
 177         clocksource_set_clock(cs, CYCLES_PER_SEC);
 178         clocksource_register(cs);
 179 }
 180
 181 void __init plat_time_init(void)
 182 {
 183         hub_rt_clocksource_init();
 184         hub_rt_clock_event_global_init();
 185         hub_rt_clock_event_init();
 186 }
 187
 188 void __cpuinit cpu_time_init(void)
 189 {
 190         lboard_t *board;
 191         klcpu_t *cpu;
 192         int cpuid;
 193
 194         /* Don't use ARCS.  ARCS is fragile.  Klconfig is simple and sane.  */
 195         board = find_lboard(KL_CONFIG_INFO(get_nasid()), KLTYPE_IP27);
 196         if (!board)
 197                 panic("Can't find board info for myself.");
 198
 199         cpuid = LOCAL_HUB_L(PI_CPU_NUM) ? IP27_CPU0_INDEX : IP27_CPU1_INDEX;
 200         cpu = (klcpu_t *) KLCF_COMP(board, cpuid);
 201         if (!cpu)
 202                 panic("No information about myself?");
 203
 204         printk("CPU %d clock is %dMHz.\n", smp_processor_id(), cpu->cpu_speed);
 205
 206         set_c0_status(SRB_TIMOCLK);
 207 }
 208
 209 void __cpuinit hub_rtc_init(cnodeid_t cnode)
 210 {
 211
 212         /*
 213          * We only need to initialize the current node.
 214          * If this is not the current node then it is a cpuless
 215          * node and timeouts will not happen there.
 216          */
 217         if (get_compact_nodeid() == cnode) {
 218                 LOCAL_HUB_S(PI_RT_EN_A, 1);
 219                 LOCAL_HUB_S(PI_RT_EN_B, 1);
 220                 LOCAL_HUB_S(PI_PROF_EN_A, 0);
 221                 LOCAL_HUB_S(PI_PROF_EN_B, 0);
 222                 LOCAL_HUB_S(PI_RT_COUNT, 0);
 223                 LOCAL_HUB_S(PI_RT_PEND_A, 0);
 224                 LOCAL_HUB_S(PI_RT_PEND_B, 0);
 225         }
 226 }
 227
 228 static int __init sgi_ip27_rtc_devinit(void)
 229 {
 230         struct resource res;
 231
 232         memset(&res, 0, sizeof(res));
 233         res.start = XPHYSADDR(KL_CONFIG_CH_CONS_INFO(master_nasid)->memory_base +
 234                               IOC3_BYTEBUS_DEV0);
 235         res.end = res.start + 32767;
 236         res.flags = IORESOURCE_MEM;
 237
 238         return IS_ERR(platform_device_register_simple("rtc-m48t35", -1,
 239                                                       &res, 1));
 240 }
 241
 242 /*
 243  * kludge make this a device_initcall after ioc3 resource conflicts
 244  * are resolved
 245  */
 246 late_initcall(sgi_ip27_rtc_devinit);