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/time.h>
  14 #include <linux/timex.h>
  15 #include <linux/mm.h>
  16 #include <linux/platform_device.h>
  17
  18 #include <asm/time.h>
  19 #include <asm/pgtable.h>
  20 #include <asm/sgialib.h>
  21 #include <asm/sn/ioc3.h>
  22 #include <asm/sn/klconfig.h>
  23 #include <asm/sn/arch.h>
  24 #include <asm/sn/addrs.h>
  25 #include <asm/sn/sn_private.h>
  26 #include <asm/sn/sn0/ip27.h>
  27 #include <asm/sn/sn0/hub.h>
  28
  29 #define TICK_SIZE (tick_nsec / 1000)
  30
  31 /* Includes for ioc3_init().  */
  32 #include <asm/sn/types.h>
  33 #include <asm/sn/sn0/addrs.h>
  34 #include <asm/sn/sn0/hubni.h>
  35 #include <asm/sn/sn0/hubio.h>
  36 #include <asm/pci/bridge.h>
  37
  38 static void enable_rt_irq(unsigned int irq)
  39 {
  40 }
  41
  42 static void disable_rt_irq(unsigned int irq)
  43 {
  44 }
  45
  46 static struct irq_chip rt_irq_type = {
  47         .name           = "SN HUB RT timer",
  48         .ack            = disable_rt_irq,
  49         .mask           = disable_rt_irq,
  50         .mask_ack       = disable_rt_irq,
  51         .unmask         = enable_rt_irq,
  52         .eoi            = enable_rt_irq,
  53 };
  54
  55 static int rt_next_event(unsigned long delta, struct clock_event_device *evt)
  56 {
  57         unsigned int cpu = smp_processor_id();
  58         int slice = cputoslice(cpu);
  59         unsigned long cnt;
  60
  61         cnt = LOCAL_HUB_L(PI_RT_COUNT);
  62         cnt += delta;
  63         LOCAL_HUB_S(PI_RT_COMPARE_A + PI_COUNT_OFFSET * slice, cnt);
  64
  65         return LOCAL_HUB_L(PI_RT_COUNT) >= cnt ? -ETIME : 0;
  66 }
  67
  68 static void rt_set_mode(enum clock_event_mode mode,
  69                 struct clock_event_device *evt)
  70 {
  71         switch (mode) {
  72         case CLOCK_EVT_MODE_ONESHOT:
  73                 /* The only mode supported */
  74                 break;
  75
  76         case CLOCK_EVT_MODE_PERIODIC:
  77         case CLOCK_EVT_MODE_UNUSED:
  78         case CLOCK_EVT_MODE_SHUTDOWN:
  79         case CLOCK_EVT_MODE_RESUME:
  80                 /* Nothing to do  */
  81                 break;
  82         }
  83 }
  84
  85 int rt_timer_irq;
  86
  87 static DEFINE_PER_CPU(struct clock_event_device, hub_rt_clockevent);
  88 static DEFINE_PER_CPU(char [11], hub_rt_name);
  89
  90 static irqreturn_t hub_rt_counter_handler(int irq, void *dev_id)
  91 {
  92         unsigned int cpu = smp_processor_id();
  93         struct clock_event_device *cd = &per_cpu(hub_rt_clockevent, cpu);
  94         int slice = cputoslice(cpu);
  95
  96         /*
  97          * Ack
  98          */
  99         LOCAL_HUB_S(PI_RT_PEND_A + PI_COUNT_OFFSET * slice, 0);
 100         cd->event_handler(cd);
 101
 102         return IRQ_HANDLED;
 103 }
 104
 105 struct irqaction hub_rt_irqaction = {
 106         .handler        = hub_rt_counter_handler,
 107         .flags          = IRQF_DISABLED | IRQF_PERCPU,
 108         .name           = "hub-rt",
 109 };
 110
 111 /*
 112  * This is a hack; we really need to figure these values out dynamically
 113  *
 114  * Since 800 ns works very well with various HUB frequencies, such as
 115  * 360, 380, 390 and 400 MHZ, we use 800 ns rtc cycle time.
 116  *
 117  * Ralf: which clock rate is used to feed the counter?
 118  */
 119 #define NSEC_PER_CYCLE          800
 120 #define CYCLES_PER_SEC          (NSEC_PER_SEC / NSEC_PER_CYCLE)
 121
 122 void __cpuinit hub_rt_clock_event_init(void)
 123 {
 124         unsigned int cpu = smp_processor_id();
 125         struct clock_event_device *cd = &per_cpu(hub_rt_clockevent, cpu);
 126         unsigned char *name = per_cpu(hub_rt_name, cpu);
 127         int irq = rt_timer_irq;
 128
 129         sprintf(name, "hub-rt %d", cpu);
 130         cd->name                = name;
 131         cd->features            = CLOCK_EVT_FEAT_ONESHOT;
 132         clockevent_set_clock(cd, CYCLES_PER_SEC);
 133         cd->max_delta_ns        = clockevent_delta2ns(0xfffffffffffff, cd);
 134         cd->min_delta_ns        = clockevent_delta2ns(0x300, cd);
 135         cd->rating              = 200;
 136         cd->irq                 = irq;
 137         cd->cpumask             = cpumask_of_cpu(cpu);
 138         cd->set_next_event      = rt_next_event;
 139         cd->set_mode            = rt_set_mode;
 140         clockevents_register_device(cd);
 141 }
 142
 143 static void __init hub_rt_clock_event_global_init(void)
 144 {
 145         int irq;
 146
 147         do {
 148                 smp_wmb();
 149                 irq = rt_timer_irq;
 150                 if (irq)
 151                         break;
 152
 153                 irq = allocate_irqno();
 154                 if (irq < 0)
 155                         panic("Allocation of irq number for timer failed");
 156         } while (xchg(&rt_timer_irq, irq));
 157
 158         set_irq_chip_and_handler(irq, &rt_irq_type, handle_percpu_irq);
 159         setup_irq(irq, &hub_rt_irqaction);
 160 }
 161
 162 static cycle_t hub_rt_read(void)
 163 {
 164         return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
 165 }
 166
 167 struct clocksource hub_rt_clocksource = {
 168         .name   = "HUB-RT",
 169         .rating = 200,
 170         .read   = hub_rt_read,
 171         .mask   = CLOCKSOURCE_MASK(52),
 172         .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
 173 };
 174
 175 static void __init hub_rt_clocksource_init(void)
 176 {
 177         struct clocksource *cs = &hub_rt_clocksource;
 178
 179         clocksource_set_clock(cs, CYCLES_PER_SEC);
 180         clocksource_register(cs);
 181 }
 182
 183 void __init plat_time_init(void)
 184 {
 185         hub_rt_clocksource_init();
 186         hub_rt_clock_event_global_init();
 187         hub_rt_clock_event_init();
 188 }
 189
 190 void __cpuinit cpu_time_init(void)
 191 {
 192         lboard_t *board;
 193         klcpu_t *cpu;
 194         int cpuid;
 195
 196         /* Don't use ARCS.  ARCS is fragile.  Klconfig is simple and sane.  */
 197         board = find_lboard(KL_CONFIG_INFO(get_nasid()), KLTYPE_IP27);
 198         if (!board)
 199                 panic("Can't find board info for myself.");
 200
 201         cpuid = LOCAL_HUB_L(PI_CPU_NUM) ? IP27_CPU0_INDEX : IP27_CPU1_INDEX;
 202         cpu = (klcpu_t *) KLCF_COMP(board, cpuid);
 203         if (!cpu)
 204                 panic("No information about myself?");
 205
 206         printk("CPU %d clock is %dMHz.\n", smp_processor_id(), cpu->cpu_speed);
 207
 208         set_c0_status(SRB_TIMOCLK);
 209 }
 210
 211 void __cpuinit hub_rtc_init(cnodeid_t cnode)
 212 {
 213
 214         /*
 215          * We only need to initialize the current node.
 216          * If this is not the current node then it is a cpuless
 217          * node and timeouts will not happen there.
 218          */
 219         if (get_compact_nodeid() == cnode) {
 220                 LOCAL_HUB_S(PI_RT_EN_A, 1);
 221                 LOCAL_HUB_S(PI_RT_EN_B, 1);
 222                 LOCAL_HUB_S(PI_PROF_EN_A, 0);
 223                 LOCAL_HUB_S(PI_PROF_EN_B, 0);
 224                 LOCAL_HUB_S(PI_RT_COUNT, 0);
 225                 LOCAL_HUB_S(PI_RT_PEND_A, 0);
 226                 LOCAL_HUB_S(PI_RT_PEND_B, 0);
 227         }
 228 }
 229
 230 static int __init sgi_ip27_rtc_devinit(void)
 231 {
 232         struct resource res;
 233
 234         memset(&res, 0, sizeof(res));
 235         res.start = XPHYSADDR(KL_CONFIG_CH_CONS_INFO(master_nasid)->memory_base +
 236                               IOC3_BYTEBUS_DEV0);
 237         res.end = res.start + 32767;
 238         res.flags = IORESOURCE_MEM;
 239
 240         return IS_ERR(platform_device_register_simple("rtc-m48t35", -1,
 241                                                       &res, 1));
 242 }
 243
 244 /*
 245  * kludge make this a device_initcall after ioc3 resource conflicts
 246  * are resolved
 247  */
 248 late_initcall(sgi_ip27_rtc_devinit);