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
  29 static 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
  44 static void set_clock_mode(enum clock_event_mode mode,
  45                            struct clock_event_device *evt)
  46 {
  47         /* Nothing to do ...  */
  48 }
  49
  50 static DEFINE_PER_CPU(struct clock_event_device, mn10300_clockevent_device);
  51 static DEFINE_PER_CPU(struct irqaction, timer_irq);
  52
  53 static 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
  69 static void event_handler(struct clock_event_device *dev)
  70 {
  71 }
  72
  73 int __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 }