Implement timer_cleanup() function for SAM7.

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

diff --git a/bertos/drv/timer.c b/bertos/drv/timer.c
index 4d1309466da6b37fb870ad244aa4f802df57f74a..a59f2a77aaa258071ac0eade8095514d536dba10 100644 (file)
--- a/bertos/drv/timer.c
+++ b/bertos/drv/timer.c
@@ -158,6 +158,8 @@ INLINE void timer_addToList(Timer *timer, List *queue)
  * When the delay indicated by the timer expires, the timer
  * device will execute the event associated with it.
  *
+ * You should not call this function on an already running timer.
+ *
  * \note Interrupt safe
  */
 void timer_add(Timer *timer)
@@ -252,14 +254,13 @@ 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));
-               timer_setSignal(&t, proc_current(), SIG_SINGLE);
+               timer_setEvent(&t);
                timer_setDelay(&t, delay);
                timer_add(&t);
-               sig_wait(SIG_SINGLE);
+               timer_waitEvent(&t);
        }
        else
 #endif /* !CONFIG_KERN_SIGNALS */
@@ -289,7 +290,27 @@ 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;
@@ -381,7 +402,7 @@ void timer_init(void)
 }
 
 
-#if (ARCH & ARCH_EMUL)
+#if (ARCH & ARCH_EMUL) || (CPU_ARM_AT91)
 /**
  * Stop timer (only used by emulator)
  */