kernel/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 DEFINE_PER_CPU(struct clock_event_device, mn10300_clockevent_device);
  45 static DEFINE_PER_CPU(struct irqaction, timer_irq);
  46
  47 static irqreturn_t timer_interrupt(int irq, void *dev_id)
  48 {
  49         struct clock_event_device *cd;
  50         unsigned int cpu = smp_processor_id();
  51
  52         if (cpu == 0)
  53                 stop_jiffies_counter();
  54         else
  55                 stop_jiffies_counter1();
  56
  57         cd = &per_cpu(mn10300_clockevent_device, cpu);
  58         cd->event_handler(cd);
  59
  60         return IRQ_HANDLED;
  61 }
  62
  63 static void event_handler(struct clock_event_device *dev)
  64 {
  65 }
  66
  67 static inline void setup_jiffies_interrupt(int irq,
  68                                            struct irqaction *action)
  69 {
  70         u16 tmp;
  71         setup_irq(irq, action);
  72         set_intr_level(irq, NUM2GxICR_LEVEL(CONFIG_TIMER_IRQ_LEVEL));
  73         GxICR(irq) |= GxICR_ENABLE | GxICR_DETECT | GxICR_REQUEST;
  74         tmp = GxICR(irq);
  75 }
  76
  77 int __init init_clockevents(void)
  78 {
  79         struct clock_event_device *cd;
  80         struct irqaction *iact;
  81         unsigned int cpu = smp_processor_id();
  82
  83         cd = &per_cpu(mn10300_clockevent_device, cpu);
  84
  85         if (cpu == 0) {
  86                 stop_jiffies_counter();
  87                 cd->irq = TMJCIRQ;
  88         } else {
  89                 stop_jiffies_counter1();
  90                 cd->irq = TMJC1IRQ;
  91         }
  92
  93         cd->name                = "Timestamp";
  94         cd->features            = CLOCK_EVT_FEAT_ONESHOT;
  95
  96         /* Calculate shift/mult. We want to spawn at least 1 second */
  97         clockevents_calc_mult_shift(cd, MN10300_JCCLK, 1);
  98
  99         /* Calculate the min / max delta */
 100         cd->max_delta_ns        = clockevent_delta2ns(TMJCBR_MAX, cd);
 101         cd->min_delta_ns        = clockevent_delta2ns(100, cd);
 102
 103         cd->rating              = 200;
 104         cd->cpumask             = cpumask_of(smp_processor_id());
 105         cd->event_handler       = event_handler;
 106         cd->set_next_event      = next_event;
 107
 108         iact = &per_cpu(timer_irq, cpu);
 109         iact->flags = IRQF_SHARED | IRQF_TIMER;
 110         iact->handler = timer_interrupt;
 111
 112         clockevents_register_device(cd);
 113
 114 #if defined(CONFIG_SMP) && !defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST)
 115         /* setup timer irq affinity so it only runs on this cpu */
 116         {
 117                 struct irq_data *data;
 118                 data = irq_get_irq_data(cd->irq);
 119                 cpumask_copy(irq_data_get_affinity_mask(data), cpumask_of(cpu));
 120                 iact->flags |= IRQF_NOBALANCING;
 121         }
 122 #endif
 123
 124         if (cpu == 0) {
 125                 reload_jiffies_counter(MN10300_JC_PER_HZ - 1);
 126                 iact->name = "CPU0 Timer";
 127         } else {
 128                 reload_jiffies_counter1(MN10300_JC_PER_HZ - 1);
 129                 iact->name = "CPU1 Timer";
 130         }
 131
 132         setup_jiffies_interrupt(cd->irq, iact);
 133
 134         return 0;
 135 }