release/src-rt-6.x.4708/linux/linux-2.6.36/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(unsigned int irq)
  40 {
  41 }
  42
  43 static void disable_rt_irq(unsigned int irq)
  44 {
  45 }
  46
  47 static struct irq_chip rt_irq_type = {
  48         .name           = "SN HUB RT timer",
  49         .ack            = disable_rt_irq,
  50         .mask           = disable_rt_irq,
  51         .mask_ack       = disable_rt_irq,
  52         .unmask         = enable_rt_irq,
  53         .eoi            = enable_rt_irq,
  54 };
  55
  56 static int rt_next_event(unsigned long delta, struct clock_event_device *evt)
  57 {
  58         unsigned int cpu = smp_processor_id();
  59         int slice = cputoslice(cpu);
  60         unsigned long cnt;
  61
  62         cnt = LOCAL_HUB_L(PI_RT_COUNT);
  63         cnt += delta;
  64         LOCAL_HUB_S(PI_RT_COMPARE_A + PI_COUNT_OFFSET * slice, cnt);
  65
  66         return LOCAL_HUB_L(PI_RT_COUNT) >= cnt ? -ETIME : 0;
  67 }
  68
  69 static void rt_set_mode(enum clock_event_mode mode,
  70                 struct clock_event_device *evt)
  71 {
  72         switch (mode) {
  73         case CLOCK_EVT_MODE_ONESHOT:
  74                 /* The only mode supported */
  75                 break;
  76
  77         case CLOCK_EVT_MODE_PERIODIC:
  78         case CLOCK_EVT_MODE_UNUSED:
  79         case CLOCK_EVT_MODE_SHUTDOWN:
  80         case CLOCK_EVT_MODE_RESUME:
  81                 /* Nothing to do  */
  82                 break;
  83         }
  84 }
  85
  86 int rt_timer_irq;
  87
  88 static DEFINE_PER_CPU(struct clock_event_device, hub_rt_clockevent);
  89 static DEFINE_PER_CPU(char [11], hub_rt_name);
  90
  91 static irqreturn_t hub_rt_counter_handler(int irq, void *dev_id)
  92 {
  93         unsigned int cpu = smp_processor_id();
  94         struct clock_event_device *cd = &per_cpu(hub_rt_clockevent, cpu);
  95         int slice = cputoslice(cpu);
  96
  97         /*
  98          * Ack
  99          */
 100         LOCAL_HUB_S(PI_RT_PEND_A + PI_COUNT_OFFSET * slice, 0);
 101         cd->event_handler(cd);
 102
 103         return IRQ_HANDLED;
 104 }
 105
 106 struct irqaction hub_rt_irqaction = {
 107         .handler        = hub_rt_counter_handler,
 108         .flags          = IRQF_DISABLED | IRQF_PERCPU | IRQF_TIMER,
 109         .name           = "hub-rt",
 110 };
 111
 112 /*
 113  * This is a hack; we really need to figure these values out dynamically
 114  *
 115  * Since 800 ns works very well with various HUB frequencies, such as
 116  * 360, 380, 390 and 400 MHZ, we use 800 ns rtc cycle time.
 117  *
 118  * Ralf: which clock rate is used to feed the counter?
 119  */
 120 #define NSEC_PER_CYCLE          800
 121 #define CYCLES_PER_SEC          (NSEC_PER_SEC / NSEC_PER_CYCLE)
 122
 123 void __cpuinit hub_rt_clock_event_init(void)
 124 {
 125         unsigned int cpu = smp_processor_id();
 126         struct clock_event_device *cd = &per_cpu(hub_rt_clockevent, cpu);
 127         unsigned char *name = per_cpu(hub_rt_name, cpu);
 128         int irq = rt_timer_irq;
 129
 130         sprintf(name, "hub-rt %d", cpu);
 131         cd->name                = name;
 132         cd->features            = CLOCK_EVT_FEAT_ONESHOT;
 133         clockevent_set_clock(cd, CYCLES_PER_SEC);
 134         cd->max_delta_ns        = clockevent_delta2ns(0xfffffffffffff, cd);
 135         cd->min_delta_ns        = clockevent_delta2ns(0x300, cd);
 136         cd->rating              = 200;
 137         cd->irq                 = irq;
 138         cd->cpumask             = cpumask_of(cpu);
 139         cd->set_next_event      = rt_next_event;
 140         cd->set_mode            = rt_set_mode;
 141         clockevents_register_device(cd);
 142 }
 143
 144 static void __init hub_rt_clock_event_global_init(void)
 145 {
 146         int irq;
 147
 148         do {
 149                 smp_wmb();
 150                 irq = rt_timer_irq;
 151                 if (irq)
 152                         break;
 153
 154                 irq = allocate_irqno();
 155                 if (irq < 0)
 156                         panic("Allocation of irq number for timer failed");
 157         } while (xchg(&rt_timer_irq, irq));
 158
 159         set_irq_chip_and_handler(irq, &rt_irq_type, handle_percpu_irq);
 160         setup_irq(irq, &hub_rt_irqaction);
 161 }
 162
 163 static cycle_t hub_rt_read(struct clocksource *cs)
 164 {
 165         return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
 166 }
 167
 168 struct clocksource hub_rt_clocksource = {
 169         .name   = "HUB-RT",
 170         .rating = 200,
 171         .read   = hub_rt_read,
 172         .mask   = CLOCKSOURCE_MASK(52),
 173         .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
 174 };
 175
 176 static void __init hub_rt_clocksource_init(void)
 177 {
 178         struct clocksource *cs = &hub_rt_clocksource;
 179
 180         clocksource_set_clock(cs, CYCLES_PER_SEC);
 181         clocksource_register(cs);
 182 }
 183
 184 void __init plat_time_init(void)
 185 {
 186         hub_rt_clocksource_init();
 187         hub_rt_clock_event_global_init();
 188         hub_rt_clock_event_init();
 189 }
 190
 191 void __cpuinit cpu_time_init(void)
 192 {
 193         lboard_t *board;
 194         klcpu_t *cpu;
 195         int cpuid;
 196
 197         /* Don't use ARCS.  ARCS is fragile.  Klconfig is simple and sane.  */
 198         board = find_lboard(KL_CONFIG_INFO(get_nasid()), KLTYPE_IP27);
 199         if (!board)
 200                 panic("Can't find board info for myself.");
 201
 202         cpuid = LOCAL_HUB_L(PI_CPU_NUM) ? IP27_CPU0_INDEX : IP27_CPU1_INDEX;
 203         cpu = (klcpu_t *) KLCF_COMP(board, cpuid);
 204         if (!cpu)
 205                 panic("No information about myself?");
 206
 207         printk("CPU %d clock is %dMHz.\n", smp_processor_id(), cpu->cpu_speed);
 208
 209         set_c0_status(SRB_TIMOCLK);
 210 }
 211
 212 void __cpuinit hub_rtc_init(cnodeid_t cnode)
 213 {
 214
 215         /*
 216          * We only need to initialize the current node.
 217          * If this is not the current node then it is a cpuless
 218          * node and timeouts will not happen there.
 219          */
 220         if (get_compact_nodeid() == cnode) {
 221                 LOCAL_HUB_S(PI_RT_EN_A, 1);
 222                 LOCAL_HUB_S(PI_RT_EN_B, 1);
 223                 LOCAL_HUB_S(PI_PROF_EN_A, 0);
 224                 LOCAL_HUB_S(PI_PROF_EN_B, 0);
 225                 LOCAL_HUB_S(PI_RT_COUNT, 0);
 226                 LOCAL_HUB_S(PI_RT_PEND_A, 0);
 227                 LOCAL_HUB_S(PI_RT_PEND_B, 0);
 228         }
 229 }
 230
 231 static int __init sgi_ip27_rtc_devinit(void)
 232 {
 233         struct resource res;
 234
 235         memset(&res, 0, sizeof(res));
 236         res.start = XPHYSADDR(KL_CONFIG_CH_CONS_INFO(master_nasid)->memory_base +
 237                               IOC3_BYTEBUS_DEV0);
 238         res.end = res.start + 32767;
 239         res.flags = IORESOURCE_MEM;
 240
 241         return IS_ERR(platform_device_register_simple("rtc-m48t35", -1,
 242                                                       &res, 1));
 243 }
 244
 245 /*
 246  * kludge make this a device_initcall after ioc3 resource conflicts
 247  * are resolved
 248  */
 249 late_initcall(sgi_ip27_rtc_devinit);