clock: refactor clock_systime_timespec() & clock_systime_ticks()

Signed-off-by: ligd <liguiding1@xiaomi.com>

Author: GUIDINGLI

sched/clock/clock_systime_ticks.c

@@ -76,86 +76,51 @@
 clock_t clock_systime_ticks(void)
 {
 #ifdef CONFIG_RTC_HIRES
-  /* Do we have a high-resolution RTC that can provide us with the time? */
-
-  if (g_rtc_enabled)
+  struct timespec ts =
     {
-      struct timespec ts;
-
-      /* Get the time from the platform specific hardware */
-
-      if (clock_systime_timespec(&ts) == OK)
-        {
-          /* Convert to a 64-bit value in microseconds,
-           * then in clock tick units.
-           */
-
-          return clock_time2ticks(&ts);
-        }
-      else
-        {
-          return 0;
-        }
-    }
-  else
-#endif
-    {
-      /* In tickless mode, all timing is controlled by platform-specific
-       * code.  Let the platform timer do the work.
-       */
-
-#if defined(CONFIG_SCHED_TICKLESS_TICK_ARGUMENT)
-      clock_t ticks;
-      if (up_timer_gettick(&ticks) == OK)
-        {
-          return ticks;
-        }
-      else
-        {
-          return 0;
-        }
-#elif defined(CONFIG_SCHED_TICKLESS)
-      struct timespec ts;
-      if (up_timer_gettime(&ts) == OK)
-        {
-          return clock_time2ticks(&ts);
-        }
-      else
-        {
-          return 0;
-        }
-#elif defined(CONFIG_SYSTEM_TIME64)
-
-      clock_t sample;
-      clock_t verify;
-
-      /* 64-bit accesses are not atomic on most architectures.  The following
-       * loop samples the 64-bit timer twice and loops in the rare event that
-       * there was 32-bit rollover between samples.
-       *
-       * If there is no 32-bit rollover, then:
-       *
-       *  - The MS 32-bits of each sample will be the same, and
-       *  - The LS 32-bits of the second sample will be greater than or equal
-       *    to the LS 32-bits for the first sample.
-       */
-
-      do
-        {
-          verify = g_system_ticks;
-          sample = g_system_ticks;
-        }
-      while ((sample &  TIMER_MASK32)  < (verify &  TIMER_MASK32) ||
-             (sample & ~TIMER_MASK32) != (verify & ~TIMER_MASK32));
+      0
+    };
 
-      return sample;
+  clock_systime_timespec(&ts);
+  return clock_time2ticks(&ts);
+#elif defined(CONFIG_SCHED_TICKLESS_TICK_ARGUMENT)
+  clock_t ticks = 0;
 
-#else /* CONFIG_SYSTEM_TIME64 */
-
-      /* Return the current system time */
-
-      return g_system_ticks;
+  up_timer_gettick(&ticks);
+  return ticks;
+#elif defined(CONFIG_SCHED_TICKLESS)
+  struct timespec ts =
+    {
+      0
+    };
 
-#endif /* CONFIG_SYSTEM_TIME64 */
+  up_timer_gettime(&ts);
+  return clock_time2ticks(&ts);
+#elif defined(CONFIG_SYSTEM_TIME64)
+  clock_t sample;
+  clock_t verify;
+
+  /* 64-bit accesses are not atomic on most architectures.  The following
+   * loop samples the 64-bit timer twice and loops in the rare event that
+   * there was 32-bit rollover between samples.
+   *
+   * If there is no 32-bit rollover, then:
+   *
+   *  - The MS 32-bits of each sample will be the same, and
+   *  - The LS 32-bits of the second sample will be greater than or equal
+   *    to the LS 32-bits for the first sample.
+   */
+
+  do
+    {
+      verify = g_system_ticks;
+      sample = g_system_ticks;
     }
+  while ((sample &  TIMER_MASK32)  < (verify &  TIMER_MASK32) ||
+         (sample & ~TIMER_MASK32) != (verify & ~TIMER_MASK32));
+
+  return sample;
+#else
+  return g_system_ticks;
+#endif
 }

sched/clock/clock_systime_timespec.c

@@ -59,76 +59,31 @@
 int clock_systime_timespec(FAR struct timespec *ts)
 {
 #ifdef CONFIG_RTC_HIRES
-  /* Do we have a high-resolution RTC that can provide us with the time? */
-
   if (g_rtc_enabled)
     {
-      int ret;
-
-      /* Get the hi-resolution time from the RTC.  This will return the
-       * current time, not the time since power up.
-       */
-
-      ret = up_rtc_gettime(ts);
-      if (ret < 0)
-        {
-          return ret;
-        }
-
-      /* Subtract the base time to this in order to convert this to the
-       * time since power up.
-       */
-
-      DEBUGASSERT(ts->tv_sec >= g_basetime.tv_sec);
-      if (ts->tv_sec < g_basetime.tv_sec)
-        {
-          /* Negative times are not supported */
-
-          return -ENOSYS;
-        }
-
-      ts->tv_sec -= g_basetime.tv_sec;
-      if (ts->tv_nsec < g_basetime.tv_nsec)
-        {
-          /* Borrow */
-
-          if (ts->tv_sec < 1)
-            {
-              /* Negative times are not supported */
+      irqstate_t flags;
 
-              return -ENOSYS;
-            }
+      up_rtc_gettime(ts);
 
-          ts->tv_sec--;
-          ts->tv_nsec += NSEC_PER_SEC;
-        }
-
-      ts->tv_nsec -= g_basetime.tv_nsec;
-      return OK;
+      flags = spin_lock_irqsave(NULL);
+      clock_timespec_subtract(ts, &g_basetime, ts);
+      spin_unlock_irqrestore(NULL, flags);
     }
   else
-#endif
     {
-      /* In tickless mode, all timing is controlled by platform-specific
-       * code.  Let the platform timer do the work.
-       */
-
-#if defined(CONFIG_SCHED_TICKLESS_TICK_ARGUMENT)
-      clock_t ticks;
-      int ret;
+      ts->tv_sec = 0;
+      ts->tv_nsec = 0;
+    }
+#elif defined(CONFIG_SCHED_TICKLESS_TICK_ARGUMENT)
+  clock_t ticks = 0;
 
-      ret = up_timer_gettick(&ticks);
-      clock_ticks2time(ts, ticks);
-      return ret;
+  up_timer_gettick(&ticks);
+  clock_ticks2time(ts, ticks);
 #elif defined(CONFIG_SCHED_TICKLESS)
-      return up_timer_gettime(ts);
+  up_timer_gettime(ts);
 #else
-      /* 64-bit microsecond calculations should improve our accuracy
-       * when the clock period is in units of microseconds.
-       */
-
-      clock_ticks2time(ts, clock_systime_ticks());
-      return OK;
+  clock_ticks2time(ts, g_system_ticks);
 #endif
-    }
+  return 0;
 }
+