From 35c5bb8e0f177643ec8d182d5a8fe2a813a3a2ad Mon Sep 17 00:00:00 2001
From: patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3>
Date: Thu, 10 Jan 2013 14:07:30 +0000
Subject: [PATCH] Fix rounding in clock_time2ticks().  From Mike Smith.

git-svn-id: http://svn.code.sf.net/p/nuttx/code/trunk@5502 42af7a65-404d-4744-a932-0658087f49c3
---
 nuttx/ChangeLog                |  2 ++
 nuttx/sched/clock_time2ticks.c | 42 ++++++++++++++++++++++++++++++----
 2 files changed, 40 insertions(+), 4 deletions(-)

diff --git a/nuttx/ChangeLog b/nuttx/ChangeLog
index 3d124073b8..758e8c862e 100644
--- a/nuttx/ChangeLog
+++ b/nuttx/ChangeLog
@@ -3897,4 +3897,6 @@
 	  arch/arm/src/lm so that is can support other members of the
 	  Stellaris family.
 	* libc/spawn:  Add file action interfaces needed by posix_spawn().
+	* sched/clock_time2ticks.c:  Another case where time was being
+	  rounded down instead of up (from Mikek Smith).
 
diff --git a/nuttx/sched/clock_time2ticks.c b/nuttx/sched/clock_time2ticks.c
index 383264d513..012f4e4f1a 100644
--- a/nuttx/sched/clock_time2ticks.c
+++ b/nuttx/sched/clock_time2ticks.c
@@ -89,14 +89,48 @@
 
 int clock_time2ticks(FAR const struct timespec *reltime, FAR int *ticks)
 {
+#ifdef CONFIG_HAVE_LONG_LONG
+  int64_t relnsec;
+
+  /* Convert the relative time into nanoseconds.  The range of the int64_t is
+   * sufficiently large that there is no real need for range checking.
+   */
+
+  relnsec = (int64_t)reltime->tv_sec * NSEC_PER_SEC +
+            (int64_t)reltime->tv_nsec;
+  
+  /* Convert nanoseconds to clock ticks, rounding up to the smallest integer
+   * that is greater than or equal to the exact number of tick.
+   */
+
+  *ticks = (int)((relnsec + NSEC_PER_TICK - 1) / NSEC_PER_TICK);
+  return OK;
+#else
   int32_t relusec;
 
-  /* Convert the relative time into microseconds.*/
+  /* This function uses an int32_t to only the relative time in microseconds.
+   * that means that the maximum supported relative time is 2,147,487.647
+   * seconds
+   */
 
-  relusec = reltime->tv_sec * USEC_PER_SEC + reltime->tv_nsec / NSEC_PER_USEC;
+#if 0 // overkill
+  DEBUGASSERT(reltime->tv_sec  <  2147487 ||
+              reltime->tv_sec  == 2147487 &&
+              reltime->tv_nsec <= 647 * NSEC_PER_MSEC);
+#endif
 
-  /* Convert microseconds to clock ticks */
+  /* Convert the relative time into microseconds, rounding up to the smallest
+   * value that is greater than or equal to the exact number of microseconds.
+   */
 
-  *ticks = relusec / USEC_PER_TICK;
+  relusec = reltime->tv_sec * USEC_PER_SEC +
+            (reltime->tv_nsec + NSEC_PER_USEC - 1) / NSEC_PER_USEC;
+
+  /* Convert microseconds to clock ticks, rounding up to the smallest integer
+   * that is greater than or equal to the exact number of tick.
+   */
+
+  *ticks = (int)((relusec + USEC_PER_TICK - 1) / USEC_PER_TICK);
   return OK;
+#endif
 }