LXR linux/arch/mn10300/kernel/cevt-mn10300.c

   1/* MN10300 clockevents
   2 *
   3 * Copyright (C) 2010 Red Hat, Inc. All Rights Reserved.
   4 * Written by Mark Salter (msalter@redhat.com)
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public Licence
   8 * as published by the Free Software Foundation; either version
   9 * 2 of the Licence, or (at your option) any later version.
  10 */
  11#include <linux/clockchips.h>
  12#include <linux/interrupt.h>
  13#include <linux/percpu.h>
  14#include <linux/smp.h>
  15#include <asm/timex.h>
  16#include "internal.h"
  17
  18#ifdef CONFIG_SMP
  19#if (CONFIG_NR_CPUS > 2) && !defined(CONFIG_GEENERIC_CLOCKEVENTS_BROADCAST)
  20#error "This doesn't scale well! Need per-core local timers."
  21#endif
  22#else /* CONFIG_SMP */
  23#define stop_jiffies_counter1()
  24#define reload_jiffies_counter1(x)
  25#define TMJC1IRQ TMJCIRQ
  26#endif
  27
  28
  29static int next_event(unsigned long delta,
  30                      struct clock_event_device *evt)
  31{
  32        unsigned int cpu = smp_processor_id();
  33
  34        if (cpu == 0) {
  35                stop_jiffies_counter();
  36                reload_jiffies_counter(delta - 1);
  37        } else {
  38                stop_jiffies_counter1();
  39                reload_jiffies_counter1(delta - 1);
  40        }
  41        return 0;
  42}
  43
  44static void set_clock_mode(enum clock_event_mode mode,
  45                           struct clock_event_device *evt)
  46{
  47        /* Nothing to do ...  */
  48}
  49
  50static DEFINE_PER_CPU(struct clock_event_device, mn10300_clockevent_device);
  51static DEFINE_PER_CPU(struct irqaction, timer_irq);
  52
  53static irqreturn_t timer_interrupt(int irq, void *dev_id)
  54{
  55        struct clock_event_device *cd;
  56        unsigned int cpu = smp_processor_id();
  57
  58        if (cpu == 0)
  59                stop_jiffies_counter();
  60        else
  61                stop_jiffies_counter1();
  62
  63        cd = &per_cpu(mn10300_clockevent_device, cpu);
  64        cd->event_handler(cd);
  65
  66        return IRQ_HANDLED;
  67}
  68
  69static void event_handler(struct clock_event_device *dev)
  70{
  71}
  72
  73int __init init_clockevents(void)
  74{
  75        struct clock_event_device *cd;
  76        struct irqaction *iact;
  77        unsigned int cpu = smp_processor_id();
  78
  79        cd = &per_cpu(mn10300_clockevent_device, cpu);
  80
  81        if (cpu == 0) {
  82                stop_jiffies_counter();
  83                cd->irq = TMJCIRQ;
  84        } else {
  85                stop_jiffies_counter1();
  86                cd->irq = TMJC1IRQ;
  87        }
  88
  89        cd->name                = "Timestamp";
  90        cd->features            = CLOCK_EVT_FEAT_ONESHOT;
  91
  92        /* Calculate the min / max delta */
  93        clockevent_set_clock(cd, MN10300_JCCLK);
  94
  95        cd->max_delta_ns        = clockevent_delta2ns(TMJCBR_MAX, cd);
  96        cd->min_delta_ns        = clockevent_delta2ns(100, cd);
  97
  98        cd->rating              = 200;
  99        cd->cpumask             = cpumask_of(smp_processor_id());
 100        cd->set_mode            = set_clock_mode;
 101        cd->event_handler       = event_handler;
 102        cd->set_next_event      = next_event;
 103
 104        iact = &per_cpu(timer_irq, cpu);
 105        iact->flags = IRQF_DISABLED | IRQF_SHARED | IRQF_TIMER;
 106        iact->handler = timer_interrupt;
 107
 108        clockevents_register_device(cd);
 109
 110#if defined(CONFIG_SMP) && !defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST)
 111        /* setup timer irq affinity so it only runs on this cpu */
 112        {
 113                struct irq_desc *desc;
 114                desc = irq_to_desc(cd->irq);
 115                cpumask_copy(desc->affinity, cpumask_of(cpu));
 116                iact->flags |= IRQF_NOBALANCING;
 117        }
 118#endif
 119
 120        if (cpu == 0) {
 121                reload_jiffies_counter(MN10300_JC_PER_HZ - 1);
 122                iact->name = "CPU0 Timer";
 123        } else {
 124                reload_jiffies_counter1(MN10300_JC_PER_HZ - 1);
 125                iact->name = "CPU1 Timer";
 126        }
 127
 128        setup_jiffies_interrupt(cd->irq, iact);
 129
 130        return 0;
 131}
 132