From 0863e771a99553e83bdbf5bdf4b8fe71fc7cf6b0 Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Fri, 26 Apr 2019 07:24:57 -0600
Subject: [PATCH] Revert "sched/clock/clock_initialize.c:  clock_inittime()
 needs to be done with CONFIG_SCHED_TICKLESS and clock_initialize should skip
 clock_inittime() for external RTC case since the RTC isn't ready yet."

This reverts commit 2bc709d4b99447f8decdc7580fdabab6dd8939b1.

Commit 2bc709d4b99447f8decdc7580fdabab6dd8939b1 was intended to handle the case where up_timer_gettime may not start from zero case.  However, this change has the side-effect of breaking every implementation of tickless mode:  After this change the tickless timer structures are used before they are initialized in clock_inittime().  Initialization happens later when up_initialize is called() when arm_timer_initialize().

Since the tickless mode timer is very special, one solution might be to

1. Rename xxx_timer_initialize to up_timer_initialize
2  Move up_timer_initialize to include/nuttx/arch.h
3.  Call it from clock subsystem instead up_initialize

Basically, this change make timer initialization almost same as rtc initialization(up_rtc_initialize).

For now, however, we just need to revert the change.
---
 sched/clock/clock_initialize.c | 36 ++++++++++++++++++++--------------
 1 file changed, 21 insertions(+), 15 deletions(-)

diff --git a/sched/clock/clock_initialize.c b/sched/clock/clock_initialize.c
index 1034fc2c5f1..8d770e388a1 100644
--- a/sched/clock/clock_initialize.c
+++ b/sched/clock/clock_initialize.c
@@ -65,9 +65,9 @@
 
 #ifndef CONFIG_SCHED_TICKLESS
 #ifdef CONFIG_SYSTEM_TIME64
-volatile uint64_t g_system_timer = INITIAL_SYSTEM_TIMER_TICKS;
+volatile uint64_t g_system_timer;
 #else
-volatile uint32_t g_system_timer = INITIAL_SYSTEM_TIMER_TICKS;
+volatile uint32_t g_system_timer;
 #endif
 #endif
 
@@ -170,31 +170,37 @@ int clock_basetime(FAR struct timespec *tp)
  *
  ****************************************************************************/
 
-#ifdef CONFIG_RTC
 static void clock_inittime(void)
 {
   /* (Re-)initialize the time value to match the RTC */
 
 #ifndef CONFIG_CLOCK_TIMEKEEPING
-  struct timespec ts;
-
+#ifndef CONFIG_RTC_HIRES
   clock_basetime(&g_basetime);
-  clock_systimespec(&ts);
+#endif
+#ifndef CONFIG_SCHED_TICKLESS
+  g_system_timer = INITIAL_SYSTEM_TIMER_TICKS;
+  if (g_system_timer > 0)
+    {
+      struct timespec ts;
 
-  /* Adjust base time to hide initial timer ticks. */
+      (void)clock_ticks2time((sclock_t)g_system_timer, &ts);
 
-  g_basetime.tv_sec  -= ts.tv_sec;
-  g_basetime.tv_nsec -= ts.tv_nsec;
-  while (g_basetime.tv_nsec < 0)
-    {
-      g_basetime.tv_nsec += NSEC_PER_SEC;
-      g_basetime.tv_sec--;
+      /* Adjust base time to hide initial timer ticks. */
+
+      g_basetime.tv_sec  -= ts.tv_sec;
+      g_basetime.tv_nsec -= ts.tv_nsec;
+      while (g_basetime.tv_nsec < 0)
+        {
+          g_basetime.tv_nsec += NSEC_PER_SEC;
+          g_basetime.tv_sec--;
+        }
     }
+#endif /* !CONFIG_SCHED_TICKLESS */
 #else
   clock_inittimekeeping();
 #endif
 }
-#endif
 
 /****************************************************************************
  * Public Functions
@@ -216,11 +222,11 @@ void clock_initialize(void)
    */
 
   up_rtc_initialize();
+#endif
 
   /* Initialize the time value to match the RTC */
 
   clock_inittime();
-#endif
 }
 
 /****************************************************************************