x15/kern/clock.c

/*
 * Copyright (c) 2017 Richard Braun.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdio.h>
#include <stdint.h>

#include <kern/atomic.h>
#include <kern/clock.h>
#include <kern/init.h>
#include <kern/percpu.h>
#include <kern/rcu.h>
#include <kern/sref.h>
#include <kern/syscnt.h>
#include <kern/thread.h>
#include <kern/timer.h>
#include <kern/work.h>
#include <machine/boot.h>
#include <machine/cpu.h>

struct clock_cpu_data
{
  struct syscnt sc_tick_intrs;
};

static struct clock_cpu_data clock_cpu_data __percpu;

union clock_global_time clock_global_time;

static inline void __init
clock_cpu_data_init (struct clock_cpu_data *cpu_data, unsigned int cpu)
{
  char name[SYSCNT_NAME_SIZE];

  snprintf (name, sizeof (name), "clock_tick_intrs/%u", cpu);
  syscnt_register (&cpu_data->sc_tick_intrs, name);
}

static int __init
clock_setup (void)
{
  for (uint32_t cpu = 0; cpu < cpu_count (); ++cpu)
    clock_cpu_data_init (percpu_ptr (clock_cpu_data, cpu), cpu);

  return (0);
}

INIT_OP_DEFINE (clock_setup,
                INIT_OP_DEP (cpu_mp_probe, true),
                INIT_OP_DEP (syscnt_setup, true));

void clock_tick_intr (void)
{
  struct clock_cpu_data *cpu_data;

  assert (thread_check_intr_context ());

  if (cpu_id () == 0)
    {
#ifdef __LP64__
      atomic_add_rlx (&clock_global_time.ticks, 1);
#else
      union clock_global_time t = { .ticks = clock_global_time.ticks };
      ++t.ticks;

      atomic_store_rlx (&clock_global_time.high2, t.high1);
      atomic_store_rel (&clock_global_time.low, t.low);
      atomic_store_rel (&clock_global_time.high1, t.high1);
#endif
    }

  timer_report_periodic_event ();
  rcu_report_periodic_event ();
  sref_report_periodic_event ();
  work_report_periodic_event ();
  thread_report_periodic_event ();

  cpu_data = cpu_local_ptr (clock_cpu_data);
  syscnt_inc (&cpu_data->sc_tick_intrs);
}