drivers/gator/gator_hrtimer_gator.c

   1 /**
   2  * Copyright (C) ARM Limited 2011-2013. 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 // gator_hrtimer_perf.c is used if perf is supported
  11 //   update, gator_hrtimer_gator.c always used until issues resolved with perf hrtimers
  12 #if 1
  13
  14 void (*callback)(void);
  15 DEFINE_PER_CPU(struct hrtimer, percpu_hrtimer);
  16 DEFINE_PER_CPU(int, hrtimer_is_active);
  17 static ktime_t profiling_interval;
  18 static void gator_hrtimer_online(void);
  19 static void gator_hrtimer_offline(void);
  20
  21 static enum hrtimer_restart gator_hrtimer_notify(struct hrtimer *hrtimer)
  22 {
  23         hrtimer_forward_now(hrtimer, profiling_interval);
  24         (*callback)();
  25         return HRTIMER_RESTART;
  26 }
  27
  28 static void gator_hrtimer_online(void)
  29 {
  30         int cpu = get_logical_cpu();
  31         struct hrtimer *hrtimer = &per_cpu(percpu_hrtimer, cpu);
  32
  33         if (per_cpu(hrtimer_is_active, cpu) || profiling_interval.tv64 == 0)
  34                 return;
  35
  36         per_cpu(hrtimer_is_active, cpu) = 1;
  37         hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
  38         hrtimer->function = gator_hrtimer_notify;
  39 #ifdef CONFIG_PREEMPT_RT_BASE
  40         hrtimer->irqsafe = 1;
  41 #endif
  42         hrtimer_start(hrtimer, profiling_interval, HRTIMER_MODE_REL_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 }
  81
  82 #endif