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ip27-timer.c

/*
 * Copytight (C) 1999, 2000, 05, 06 Ralf Baechle (ralf@linux-mips.org)
 * Copytight (C) 1999, 2000 Silicon Graphics, Inc.
 */
#include <linux/bcd.h>
#include <linux/clockchips.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/param.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/mm.h>
#include <linux/platform_device.h>

#include <asm/time.h>
#include <asm/pgtable.h>
#include <asm/sgialib.h>
#include <asm/sn/ioc3.h>
#include <asm/sn/klconfig.h>
#include <asm/sn/arch.h>
#include <asm/sn/addrs.h>
#include <asm/sn/sn_private.h>
#include <asm/sn/sn0/ip27.h>
#include <asm/sn/sn0/hub.h>

#define TICK_SIZE (tick_nsec / 1000)

/* Includes for ioc3_init().  */
#include <asm/sn/types.h>
#include <asm/sn/sn0/addrs.h>
#include <asm/sn/sn0/hubni.h>
#include <asm/sn/sn0/hubio.h>
#include <asm/pci/bridge.h>

static void enable_rt_irq(unsigned int irq)
{
}

static void disable_rt_irq(unsigned int irq)
{
}

static struct irq_chip rt_irq_type = {
      .name       = "SN HUB RT timer",
      .ack        = disable_rt_irq,
      .mask       = disable_rt_irq,
      .mask_ack   = disable_rt_irq,
      .unmask           = enable_rt_irq,
      .eoi        = enable_rt_irq,
};

static int rt_next_event(unsigned long delta, struct clock_event_device *evt)
{
      unsigned int cpu = smp_processor_id();
      int slice = cputoslice(cpu);
      unsigned long cnt;

      cnt = LOCAL_HUB_L(PI_RT_COUNT);
      cnt += delta;
      LOCAL_HUB_S(PI_RT_COMPARE_A + PI_COUNT_OFFSET * slice, cnt);

      return LOCAL_HUB_L(PI_RT_COUNT) >= cnt ? -ETIME : 0;
}

static void rt_set_mode(enum clock_event_mode mode,
            struct clock_event_device *evt)
{
      switch (mode) {
      case CLOCK_EVT_MODE_ONESHOT:
            /* The only mode supported */
            break;

      case CLOCK_EVT_MODE_PERIODIC:
      case CLOCK_EVT_MODE_UNUSED:
      case CLOCK_EVT_MODE_SHUTDOWN:
      case CLOCK_EVT_MODE_RESUME:
            /* Nothing to do  */
            break;
      }
}

int rt_timer_irq;

static DEFINE_PER_CPU(struct clock_event_device, hub_rt_clockevent);
static DEFINE_PER_CPU(char [11], hub_rt_name);

static irqreturn_t hub_rt_counter_handler(int irq, void *dev_id)
{
      unsigned int cpu = smp_processor_id();
      struct clock_event_device *cd = &per_cpu(hub_rt_clockevent, cpu);
      int slice = cputoslice(cpu);

      /*
       * Ack
       */
      LOCAL_HUB_S(PI_RT_PEND_A + PI_COUNT_OFFSET * slice, 0);
      cd->event_handler(cd);

      return IRQ_HANDLED;
}

struct irqaction hub_rt_irqaction = {
      .handler    = hub_rt_counter_handler,
      .flags            = IRQF_DISABLED | IRQF_PERCPU,
      .name       = "hub-rt",
};

/*
 * This is a hack; we really need to figure these values out dynamically
 *
 * Since 800 ns works very well with various HUB frequencies, such as
 * 360, 380, 390 and 400 MHZ, we use 800 ns rtc cycle time.
 *
 * Ralf: which clock rate is used to feed the counter?
 */
#define NSEC_PER_CYCLE        800
#define CYCLES_PER_SEC        (NSEC_PER_SEC / NSEC_PER_CYCLE)

void __cpuinit hub_rt_clock_event_init(void)
{
      unsigned int cpu = smp_processor_id();
      struct clock_event_device *cd = &per_cpu(hub_rt_clockevent, cpu);
      unsigned char *name = per_cpu(hub_rt_name, cpu);
      int irq = rt_timer_irq;

      sprintf(name, "hub-rt %d", cpu);
      cd->name          = name;
      cd->features            = CLOCK_EVT_FEAT_ONESHOT;
      clockevent_set_clock(cd, CYCLES_PER_SEC);
      cd->max_delta_ns        = clockevent_delta2ns(0xfffffffffffff, cd);
      cd->min_delta_ns        = clockevent_delta2ns(0x300, cd);
      cd->rating        = 200;
      cd->irq                 = irq;
      cd->cpumask       = cpumask_of_cpu(cpu);
      cd->set_next_event      = rt_next_event;
      cd->set_mode            = rt_set_mode;
      clockevents_register_device(cd);
}

static void __init hub_rt_clock_event_global_init(void)
{
      int irq;

      do {
            smp_wmb();
            irq = rt_timer_irq;
            if (irq)
                  break;

            irq = allocate_irqno();
            if (irq < 0)
                  panic("Allocation of irq number for timer failed");
      } while (xchg(&rt_timer_irq, irq));

      set_irq_chip_and_handler(irq, &rt_irq_type, handle_percpu_irq);
      setup_irq(irq, &hub_rt_irqaction);
}

static cycle_t hub_rt_read(void)
{
      return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
}

struct clocksource hub_rt_clocksource = {
      .name = "HUB-RT",
      .rating     = 200,
      .read = hub_rt_read,
      .mask = CLOCKSOURCE_MASK(52),
      .flags      = CLOCK_SOURCE_IS_CONTINUOUS,
};

static void __init hub_rt_clocksource_init(void)
{
      struct clocksource *cs = &hub_rt_clocksource;

      clocksource_set_clock(cs, CYCLES_PER_SEC);
      clocksource_register(cs);
}

void __init plat_time_init(void)
{
      hub_rt_clocksource_init();
      hub_rt_clock_event_global_init();
      hub_rt_clock_event_init();
}

void __cpuinit cpu_time_init(void)
{
      lboard_t *board;
      klcpu_t *cpu;
      int cpuid;

      /* Don't use ARCS.  ARCS is fragile.  Klconfig is simple and sane.  */
      board = find_lboard(KL_CONFIG_INFO(get_nasid()), KLTYPE_IP27);
      if (!board)
            panic("Can't find board info for myself.");

      cpuid = LOCAL_HUB_L(PI_CPU_NUM) ? IP27_CPU0_INDEX : IP27_CPU1_INDEX;
      cpu = (klcpu_t *) KLCF_COMP(board, cpuid);
      if (!cpu)
            panic("No information about myself?");

      printk("CPU %d clock is %dMHz.\n", smp_processor_id(), cpu->cpu_speed);

      set_c0_status(SRB_TIMOCLK);
}

void __cpuinit hub_rtc_init(cnodeid_t cnode)
{

      /*
       * We only need to initialize the current node.
       * If this is not the current node then it is a cpuless
       * node and timeouts will not happen there.
       */
      if (get_compact_nodeid() == cnode) {
            LOCAL_HUB_S(PI_RT_EN_A, 1);
            LOCAL_HUB_S(PI_RT_EN_B, 1);
            LOCAL_HUB_S(PI_PROF_EN_A, 0);
            LOCAL_HUB_S(PI_PROF_EN_B, 0);
            LOCAL_HUB_S(PI_RT_COUNT, 0);
            LOCAL_HUB_S(PI_RT_PEND_A, 0);
            LOCAL_HUB_S(PI_RT_PEND_B, 0);
      }
}

static int __init sgi_ip27_rtc_devinit(void)
{
      struct resource res;

      memset(&res, 0, sizeof(res));
      res.start = XPHYSADDR(KL_CONFIG_CH_CONS_INFO(master_nasid)->memory_base +
                        IOC3_BYTEBUS_DEV0);
      res.end = res.start + 32767;
      res.flags = IORESOURCE_MEM;

      return IS_ERR(platform_device_register_simple("rtc-m48t35", -1,
                                          &res, 1));
}

/*
 * kludge make this a device_initcall after ioc3 resource conflicts
 * are resolved
 */
late_initcall(sgi_ip27_rtc_devinit);

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