driver/gator_hrtimer_gator.c

   1 /**
   2  * Copyright (C) ARM Limited 2011-2014. All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  */
   9
  10 void (*callback)(void);
  11 DEFINE_PER_CPU(struct hrtimer, percpu_hrtimer);
  12 DEFINE_PER_CPU(ktime_t, hrtimer_expire);
  13 DEFINE_PER_CPU(int, hrtimer_is_active);
  14 static ktime_t profiling_interval;
  15 static void gator_hrtimer_online(void);
  16 static void gator_hrtimer_offline(void);
  17
  18 static enum hrtimer_restart gator_hrtimer_notify(struct hrtimer *hrtimer)
  19 {
  20         int cpu = get_logical_cpu();
  21         hrtimer_forward(hrtimer, per_cpu(hrtimer_expire, cpu), profiling_interval);
  22         per_cpu(hrtimer_expire, cpu) = ktime_add(per_cpu(hrtimer_expire, cpu), profiling_interval);
  23         (*callback)();
  24         return HRTIMER_RESTART;
  25 }
  26
  27 static void gator_hrtimer_online(void)
  28 {
  29         int cpu = get_logical_cpu();
  30         struct hrtimer *hrtimer = &per_cpu(percpu_hrtimer, cpu);
  31
  32         if (per_cpu(hrtimer_is_active, cpu) || profiling_interval.tv64 == 0)
  33                 return;
  34
  35         per_cpu(hrtimer_is_active, cpu) = 1;
  36         hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
  37         hrtimer->function = gator_hrtimer_notify;
  38 #ifdef CONFIG_PREEMPT_RT_BASE
  39         hrtimer->irqsafe = 1;
  40 #endif
  41         per_cpu(hrtimer_expire, cpu) = ktime_add(hrtimer->base->get_time(), profiling_interval);
  42         hrtimer_start(hrtimer, per_cpu(hrtimer_expire, cpu), HRTIMER_MODE_ABS_PINNED);
  43 }
  44
  45 static void gator_hrtimer_offline(void)
  46 {
  47         int cpu = get_logical_cpu();
  48         struct hrtimer *hrtimer = &per_cpu(percpu_hrtimer, cpu);
  49
  50         if (!per_cpu(hrtimer_is_active, cpu))
  51                 return;
  52
  53         per_cpu(hrtimer_is_active, cpu) = 0;
  54         hrtimer_cancel(hrtimer);
  55 }
  56
  57 static int gator_hrtimer_init(int interval, void (*func)(void))
  58 {
  59         int cpu;
  60
  61         (callback) = (func);
  62
  63         for_each_present_cpu(cpu) {
  64                 per_cpu(hrtimer_is_active, cpu) = 0;
  65         }
  66
  67         // calculate profiling interval
  68         if (interval > 0) {
  69                 profiling_interval = ns_to_ktime(1000000000UL / interval);
  70         } else {
  71                 profiling_interval.tv64 = 0;
  72         }
  73
  74         return 0;
  75 }
  76
  77 static void gator_hrtimer_shutdown(void)
  78 {
  79         /* empty */
  80 }