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/sched_clock.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/kernel_stat.h>
  13 #include <linux/param.h>
  14 #include <linux/smp.h>
  15 #include <linux/time.h>
  16 #include <linux/timex.h>
  17 #include <linux/mm.h>
  18 #include <linux/platform_device.h>
  19
  20 #include <asm/time.h>
  21 #include <asm/pgtable.h>
  22 #include <asm/sgialib.h>
  23 #include <asm/sn/ioc3.h>
  24 #include <asm/sn/klconfig.h>
  25 #include <asm/sn/arch.h>
  26 #include <asm/sn/addrs.h>
  27 #include <asm/sn/sn_private.h>
  28 #include <asm/sn/sn0/ip27.h>
  29 #include <asm/sn/sn0/hub.h>
  30
  31 #define TICK_SIZE (tick_nsec / 1000)
  32
  33 /* Includes for ioc3_init().  */
  34 #include <asm/sn/types.h>
  35 #include <asm/sn/sn0/addrs.h>
  36 #include <asm/sn/sn0/hubni.h>
  37 #include <asm/sn/sn0/hubio.h>
  38 #include <asm/pci/bridge.h>
  39
  40 static void enable_rt_irq(struct irq_data *d)
  41 {
  42 }
  43
  44 static void disable_rt_irq(struct irq_data *d)
  45 {
  46 }
  47
  48 static struct irq_chip rt_irq_type = {
  49         .name           = "SN HUB RT timer",
  50         .irq_mask       = disable_rt_irq,
  51         .irq_unmask     = enable_rt_irq,
  52 };
  53
  54 static int rt_next_event(unsigned long delta, struct clock_event_device *evt)
  55 {
  56         unsigned int cpu = smp_processor_id();
  57         int slice = cputoslice(cpu);
  58         unsigned long cnt;
  59
  60         cnt = LOCAL_HUB_L(PI_RT_COUNT);
  61         cnt += delta;
  62         LOCAL_HUB_S(PI_RT_COMPARE_A + PI_COUNT_OFFSET * slice, cnt);
  63
  64         return LOCAL_HUB_L(PI_RT_COUNT) >= cnt ? -ETIME : 0;
  65 }
  66
  67 unsigned int rt_timer_irq;
  68
  69 static DEFINE_PER_CPU(struct clock_event_device, hub_rt_clockevent);
  70 static DEFINE_PER_CPU(char [11], hub_rt_name);
  71
  72 static irqreturn_t hub_rt_counter_handler(int irq, void *dev_id)
  73 {
  74         unsigned int cpu = smp_processor_id();
  75         struct clock_event_device *cd = &per_cpu(hub_rt_clockevent, cpu);
  76         int slice = cputoslice(cpu);
  77
  78         /*
  79          * Ack
  80          */
  81         LOCAL_HUB_S(PI_RT_PEND_A + PI_COUNT_OFFSET * slice, 0);
  82         cd->event_handler(cd);
  83
  84         return IRQ_HANDLED;
  85 }
  86
  87 struct irqaction hub_rt_irqaction = {
  88         .handler        = hub_rt_counter_handler,
  89         .flags          = IRQF_PERCPU | IRQF_TIMER,
  90         .name           = "hub-rt",
  91 };
  92
  93 /*
  94  * This is a hack; we really need to figure these values out dynamically
  95  *
  96  * Since 800 ns works very well with various HUB frequencies, such as
  97  * 360, 380, 390 and 400 MHZ, we use 800 ns rtc cycle time.
  98  *
  99  * Ralf: which clock rate is used to feed the counter?
 100  */
 101 #define NSEC_PER_CYCLE          800
 102 #define CYCLES_PER_SEC          (NSEC_PER_SEC / NSEC_PER_CYCLE)
 103
 104 void hub_rt_clock_event_init(void)
 105 {
 106         unsigned int cpu = smp_processor_id();
 107         struct clock_event_device *cd = &per_cpu(hub_rt_clockevent, cpu);
 108         unsigned char *name = per_cpu(hub_rt_name, cpu);
 109         int irq = rt_timer_irq;
 110
 111         sprintf(name, "hub-rt %d", cpu);
 112         cd->name                = name;
 113         cd->features            = CLOCK_EVT_FEAT_ONESHOT;
 114         clockevent_set_clock(cd, CYCLES_PER_SEC);
 115         cd->max_delta_ns        = clockevent_delta2ns(0xfffffffffffff, cd);
 116         cd->min_delta_ns        = clockevent_delta2ns(0x300, cd);
 117         cd->rating              = 200;
 118         cd->irq                 = irq;
 119         cd->cpumask             = cpumask_of(cpu);
 120         cd->set_next_event      = rt_next_event;
 121         clockevents_register_device(cd);
 122 }
 123
 124 static void __init hub_rt_clock_event_global_init(void)
 125 {
 126         int irq;
 127
 128         do {
 129                 smp_wmb();
 130                 irq = rt_timer_irq;
 131                 if (irq)
 132                         break;
 133
 134                 irq = allocate_irqno();
 135                 if (irq < 0)
 136                         panic("Allocation of irq number for timer failed");
 137         } while (xchg(&rt_timer_irq, irq));
 138
 139         irq_set_chip_and_handler(irq, &rt_irq_type, handle_percpu_irq);
 140         setup_irq(irq, &hub_rt_irqaction);
 141 }
 142
 143 static cycle_t hub_rt_read(struct clocksource *cs)
 144 {
 145         return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
 146 }
 147
 148 struct clocksource hub_rt_clocksource = {
 149         .name   = "HUB-RT",
 150         .rating = 200,
 151         .read   = hub_rt_read,
 152         .mask   = CLOCKSOURCE_MASK(52),
 153         .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
 154 };
 155
 156 static u64 notrace hub_rt_read_sched_clock(void)
 157 {
 158         return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
 159 }
 160
 161 static void __init hub_rt_clocksource_init(void)
 162 {
 163         struct clocksource *cs = &hub_rt_clocksource;
 164
 165         clocksource_register_hz(cs, CYCLES_PER_SEC);
 166
 167         sched_clock_register(hub_rt_read_sched_clock, 52, CYCLES_PER_SEC);
 168 }
 169
 170 void __init plat_time_init(void)
 171 {
 172         hub_rt_clocksource_init();
 173         hub_rt_clock_event_global_init();
 174         hub_rt_clock_event_init();
 175 }
 176
 177 void cpu_time_init(void)
 178 {
 179         lboard_t *board;
 180         klcpu_t *cpu;
 181         int cpuid;
 182
 183         /* Don't use ARCS.  ARCS is fragile.  Klconfig is simple and sane.  */
 184         board = find_lboard(KL_CONFIG_INFO(get_nasid()), KLTYPE_IP27);
 185         if (!board)
 186                 panic("Can't find board info for myself.");
 187
 188         cpuid = LOCAL_HUB_L(PI_CPU_NUM) ? IP27_CPU0_INDEX : IP27_CPU1_INDEX;
 189         cpu = (klcpu_t *) KLCF_COMP(board, cpuid);
 190         if (!cpu)
 191                 panic("No information about myself?");
 192
 193         printk("CPU %d clock is %dMHz.\n", smp_processor_id(), cpu->cpu_speed);
 194
 195         set_c0_status(SRB_TIMOCLK);
 196 }
 197
 198 void hub_rtc_init(cnodeid_t cnode)
 199 {
 200
 201         /*
 202          * We only need to initialize the current node.
 203          * If this is not the current node then it is a cpuless
 204          * node and timeouts will not happen there.
 205          */
 206         if (get_compact_nodeid() == cnode) {
 207                 LOCAL_HUB_S(PI_RT_EN_A, 1);
 208                 LOCAL_HUB_S(PI_RT_EN_B, 1);
 209                 LOCAL_HUB_S(PI_PROF_EN_A, 0);
 210                 LOCAL_HUB_S(PI_PROF_EN_B, 0);
 211                 LOCAL_HUB_S(PI_RT_COUNT, 0);
 212                 LOCAL_HUB_S(PI_RT_PEND_A, 0);
 213                 LOCAL_HUB_S(PI_RT_PEND_B, 0);
 214         }
 215 }
 216
 217 static int __init sgi_ip27_rtc_devinit(void)
 218 {
 219         struct resource res;
 220
 221         memset(&res, 0, sizeof(res));
 222         res.start = XPHYSADDR(KL_CONFIG_CH_CONS_INFO(master_nasid)->memory_base +
 223                               IOC3_BYTEBUS_DEV0);
 224         res.end = res.start + 32767;
 225         res.flags = IORESOURCE_MEM;
 226
 227         return IS_ERR(platform_device_register_simple("rtc-m48t35", -1,
 228                                                       &res, 1));
 229 }
 230
 231 /*
 232  * kludge make this a device_initcall after ioc3 resource conflicts
 233  * are resolved
 234  */
 235 late_initcall(sgi_ip27_rtc_devinit);