aos/time/time.cc

#include "aos/time/time.h"

#include <inttypes.h>
#include <string.h>

#include <atomic>
#include <chrono>

#ifdef __linux__

#include "aos/mutex/mutex.h"
#include "glog/logging.h"

#else  // __linux__

#include "motors/core/kinetis.h"

// The systick interrupt increments this every 1ms.
extern "C" volatile uint32_t systick_millis_count;

#endif  // __linux__

namespace chrono = ::std::chrono;

#ifdef __linux__

namespace std {
namespace this_thread {
template <>
void sleep_until(const ::aos::monotonic_clock::time_point &end_time) {
  struct timespec end_time_timespec;
  ::std::chrono::seconds sec =
      ::std::chrono::duration_cast<::std::chrono::seconds>(
          end_time.time_since_epoch());
  ::std::chrono::nanoseconds nsec =
      ::std::chrono::duration_cast<::std::chrono::nanoseconds>(
          end_time.time_since_epoch() - sec);
  end_time_timespec.tv_sec = sec.count();
  end_time_timespec.tv_nsec = nsec.count();
  int returnval;
  do {
    returnval = clock_nanosleep(CLOCK_MONOTONIC, TIMER_ABSTIME,
                                &end_time_timespec, nullptr);
    PCHECK(returnval == 0 || returnval == EINTR)
        << ": clock_nanosleep(" << static_cast<uintmax_t>(CLOCK_MONOTONIC)
        << ", TIMER_ABSTIME, " << &end_time_timespec << ", nullptr) failed";
  } while (returnval != 0);
}

}  // namespace this_thread
}  // namespace std

#endif  // __linux__

namespace aos {
namespace time {

struct timespec to_timespec(
    const ::aos::monotonic_clock::duration duration) {
  struct timespec time_timespec;
  ::std::chrono::seconds sec =
      ::std::chrono::duration_cast<::std::chrono::seconds>(duration);
  ::std::chrono::nanoseconds nsec =
      ::std::chrono::duration_cast<::std::chrono::nanoseconds>(duration - sec);
  time_timespec.tv_sec = sec.count();
  time_timespec.tv_nsec = nsec.count();
  return time_timespec;
}

struct timespec to_timespec(
    const ::aos::monotonic_clock::time_point time) {
  return to_timespec(time.time_since_epoch());
}
}  // namespace time

constexpr monotonic_clock::time_point monotonic_clock::min_time;
constexpr monotonic_clock::time_point monotonic_clock::max_time;
constexpr realtime_clock::time_point realtime_clock::min_time;
constexpr realtime_clock::time_point realtime_clock::max_time;

monotonic_clock::time_point monotonic_clock::now() noexcept {
#ifdef __linux__
  struct timespec current_time;
  PCHECK(clock_gettime(CLOCK_MONOTONIC, &current_time) == 0)
      << ": clock_gettime(" << static_cast<uintmax_t>(CLOCK_MONOTONIC) << ", "
      << &current_time << ") failed";

  return time_point(::std::chrono::seconds(current_time.tv_sec) +
                    ::std::chrono::nanoseconds(current_time.tv_nsec));

#else  // __linux__

  __disable_irq();
  const uint32_t current_counter = SYST_CVR;
  uint32_t ms_count = systick_millis_count;
  const uint32_t istatus = SCB_ICSR;
  __enable_irq();
  // If the interrupt is pending and the timer has already wrapped from 0 back
  // up to its max, then add another ms.
  if ((istatus & SCB_ICSR_PENDSTSET) && current_counter > 50) {
    ++ms_count;
  }

  // It counts down, but everything we care about counts up.
  const uint32_t counter_up = ((F_CPU / 1000) - 1) - current_counter;

  // "3.2.1.2 System Tick Timer" in the TRM says "The System Tick Timer's clock
  // source is always the core clock, FCLK".
  using systick_duration =
      std::chrono::duration<uint32_t, std::ratio<1, F_CPU>>;

  return time_point(aos::time::round<std::chrono::nanoseconds>(
      std::chrono::milliseconds(ms_count) + systick_duration(counter_up)));

#endif  // __linux__
}

#ifdef __linux__
realtime_clock::time_point realtime_clock::now() noexcept {
  struct timespec current_time;
  PCHECK(clock_gettime(CLOCK_REALTIME, &current_time) == 0)
      << "clock_gettime(" << static_cast<uintmax_t>(CLOCK_REALTIME) << ", "
      << &current_time << ") failed";

  return time_point(::std::chrono::seconds(current_time.tv_sec) +
                    ::std::chrono::nanoseconds(current_time.tv_nsec));
}
#endif  // __linux__

}  // namespace aos