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(ktime_t, hrtimer_expire);
  17 DEFINE_PER_CPU(int, hrtimer_is_active);
  18 static ktime_t profiling_interval;
  19 static void gator_hrtimer_online(void);
  20 static void gator_hrtimer_offline(void);
  21
  22 static enum hrtimer_restart gator_hrtimer_notify(struct hrtimer *hrtimer)
  23 {
  24         int cpu = get_logical_cpu();
  25         hrtimer_forward(hrtimer, per_cpu(hrtimer_expire, cpu), profiling_interval);
  26         per_cpu(hrtimer_expire, cpu) = ktime_add(per_cpu(hrtimer_expire, cpu), profiling_interval);
  27         (*callback)();
  28         return HRTIMER_RESTART;
  29 }
  30
  31 static void gator_hrtimer_online(void)
  32 {
  33         int cpu = get_logical_cpu();
  34         struct hrtimer *hrtimer = &per_cpu(percpu_hrtimer, cpu);
  35
  36         if (per_cpu(hrtimer_is_active, cpu) || profiling_interval.tv64 == 0)
  37                 return;
  38
  39         per_cpu(hrtimer_is_active, cpu) = 1;
  40         hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
  41         hrtimer->function = gator_hrtimer_notify;
  42 #ifdef CONFIG_PREEMPT_RT_BASE
  43         hrtimer->irqsafe = 1;
  44 #endif
  45         per_cpu(hrtimer_expire, cpu) = ktime_add(hrtimer->base->get_time(), profiling_interval);
  46         hrtimer_start(hrtimer, per_cpu(hrtimer_expire, cpu), HRTIMER_MODE_ABS_PINNED);
  47 }
  48
  49 static void gator_hrtimer_offline(void)
  50 {
  51         int cpu = get_logical_cpu();
  52         struct hrtimer *hrtimer = &per_cpu(percpu_hrtimer, cpu);
  53
  54         if (!per_cpu(hrtimer_is_active, cpu))
  55                 return;
  56
  57         per_cpu(hrtimer_is_active, cpu) = 0;
  58         hrtimer_cancel(hrtimer);
  59 }
  60
  61 static int gator_hrtimer_init(int interval, void (*func)(void))
  62 {
  63         int cpu;
  64
  65         (callback) = (func);
  66
  67         for_each_present_cpu(cpu) {
  68                 per_cpu(hrtimer_is_active, cpu) = 0;
  69         }
  70
  71         // calculate profiling interval
  72         if (interval > 0) {
  73                 profiling_interval = ns_to_ktime(1000000000UL / interval);
  74         } else {
  75                 profiling_interval.tv64 = 0;
  76         }
  77
  78         return 0;
  79 }
  80
  81 static void gator_hrtimer_shutdown(void)
  82 {
  83         /* empty */
  84 }
  85
  86 #endif