Add handy functions for handling non recurrent timeouts.

[bertos.git] / bertos / drv / timer.c

diff --git a/bertos/drv/timer.c b/bertos/drv/timer.c
index 4d1309466da6b37fb870ad244aa4f802df57f74a..a64a839ca76ea5415b5f488c3edaefd0695e10cd 100644 (file)
--- a/bertos/drv/timer.c
+++ b/bertos/drv/timer.c
@@ -127,10 +127,6 @@ INLINE void timer_addToList(Timer *timer, List *queue)
        ASSERT(timer->magic != TIMER_MAGIC_ACTIVE);
        DB(timer->magic = TIMER_MAGIC_ACTIVE;)
 
-
-       /* Calculate expiration time for this timer */
-       timer->tick = _clock + timer->_delay;
-
        /*
         * Search for the first node whose expiration time is
         * greater than the timer we want to add.
@@ -162,7 +158,12 @@ INLINE void timer_addToList(Timer *timer, List *queue)
  */
 void timer_add(Timer *timer)
 {
-       ATOMIC(timer_addToList(timer, &timers_queue));
+       ATOMIC(
+               /* Calculate expiration time for this timer */
+               timer->tick = _clock + timer->_delay;
+
+               timer_addToList(timer, &timers_queue);
+       );
 }
 
 /**
@@ -212,9 +213,18 @@ INLINE void timer_poll(List *queue)
  */
 void synctimer_add(Timer *timer, List *queue)
 {
+       timer->tick = timer_clock() + timer->_delay;
+
+       timer_addToList(timer, queue);
+}
+
+void synctimer_readd(Timer *timer, List *queue)
+{
+       timer->tick += timer->_delay;
        timer_addToList(timer, queue);
 }
 
+
 /**
  * Simple synchronous timer based scheduler polling routine.
  *
@@ -252,7 +262,7 @@ void timer_delayTicks(ticks_t delay)
 
 #if CONFIG_KERN_SIGNALS
        Timer t;
-
+       DB(t.magic = TIMER_MAGIC_INACTIVE;)
        if (proc_preemptAllowed())
        {
                ASSERT(!sig_check(SIG_SINGLE));
@@ -289,7 +299,27 @@ void timer_busyWait(hptime_t delay)
        for (;;)
        {
                now = timer_hw_hpread();
-               delta = (now < prev) ? (TIMER_HW_CNT - prev + now) : (now - prev);
+               /*
+                * The timer counter may wrap here and "prev" can become
+                * greater than "now". So, be sure to always evaluate a
+                * coherent timer difference:
+                *
+                * 0     prev            now   TIMER_HW_CNT
+                * |_____|_______________|_____|
+                *        ^^^^^^^^^^^^^^^
+                * delta = now - prev
+                *
+                * 0     now             prev  TIMER_HW_CNT
+                * |_____|_______________|_____|
+                *  ^^^^^                 ^^^^^
+                * delta = (TIMER_HW_CNT - prev) + now
+                *
+                * NOTE: TIMER_HW_CNT can be any value, not necessarily a power
+                * of 2. For this reason the "%" operator is not suitable for
+                * the generic case.
+                */
+               delta = (now < prev) ? ((hptime_t)TIMER_HW_CNT - prev + now) :
+                                               (now - prev);
                if (delta >= delay)
                        break;
                delay -= delta;
@@ -381,17 +411,14 @@ void timer_init(void)
 }
 
 
-#if (ARCH & ARCH_EMUL)
+#if (ARCH & ARCH_EMUL) || (CPU_ARM_AT91)
 /**
- * Stop timer (only used by emulator)
+ * Stop timer
  */
 void timer_cleanup(void)
 {
        MOD_CLEANUP(timer);
 
        timer_hw_cleanup();
-
-       // Hmmm... apparently, the demo app does not cleanup properly
-       //ASSERT(LIST_EMPTY(&timers_queue));
 }
-#endif /* ARCH_EMUL */
+#endif