From 953eab4dbf1d0c3971935d1eca5d172209e80384 Mon Sep 17 00:00:00 2001
From: Giovanni Di Sirio <gdisirio@gmail.com>
Date: Sun, 15 Mar 2015 11:51:46 +0000
Subject: Tickless Mode improvements and more assertions added.

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@7771 35acf78f-673a-0410-8e92-d51de3d6d3f4
---
 os/rt/include/chvt.h                     | 47 ++++++++++++++++++--------------
 testhal/STM32/STM32F4xx/IRQ_STORM/main.c |  1 +
 2 files changed, 27 insertions(+), 21 deletions(-)

diff --git a/os/rt/include/chvt.h b/os/rt/include/chvt.h
index 01cfbdeee..80465fbcd 100644
--- a/os/rt/include/chvt.h
+++ b/os/rt/include/chvt.h
@@ -448,10 +448,10 @@ static inline void chVTDoTickI(void) {
 #if CH_CFG_ST_TIMEDELTA == 0
   ch.vtlist.vt_systime++;
   if (&ch.vtlist != (virtual_timers_list_t *)ch.vtlist.vt_next) {
-    virtual_timer_t *vtp;
-
+    /* The list is not empty, processing elements on top.*/
     --ch.vtlist.vt_next->vt_delta;
     while (ch.vtlist.vt_next->vt_delta == (systime_t)0) {
+      virtual_timer_t *vtp;
       vtfunc_t fn;
 
       vtp = ch.vtlist.vt_next;
@@ -466,11 +466,17 @@ static inline void chVTDoTickI(void) {
   }
 #else /* CH_CFG_ST_TIMEDELTA > 0 */
   virtual_timer_t *vtp;
-  systime_t now;
+  systime_t now, delta;
+
+  /* The list is assumed to be non-empty because an tick interrupt just
+     occurred.*/
+  chDbgAssert(&ch.vtlist != (virtual_timers_list_t *)ch.vtlist.vt_next,
+              "timers list empty");
 
+  /* Timers processing loop.*/
+  vtp = ch.vtlist.vt_next;
   while (true) {
     vtfunc_t fn;
-    systime_t delta;
 
     /* Getting the current system time and calculating the time window since
        the last time has expired.*/
@@ -479,13 +485,11 @@ static inline void chVTDoTickI(void) {
 
     /* The next element is outside the current time window, the loop
        is stopped here.*/
-    vtp = ch.vtlist.vt_next;
     if (vtp->vt_delta > delta) {
       break;
     }
 
     /* The "last time" becomes this timer's expiration time.*/
-    delta -= vtp->vt_delta;
     ch.vtlist.vt_lasttime += vtp->vt_delta;
 
     /* The timer is removed from the list and marked as non-armed.*/
@@ -493,27 +497,28 @@ static inline void chVTDoTickI(void) {
     ch.vtlist.vt_next = vtp->vt_next;
     fn = vtp->vt_func;
     vtp->vt_func = NULL;
+    chSysUnlockFromISR();
 
     /* The callback is invoked outside the kernel critical zone.*/
-    chSysUnlockFromISR();
     fn(vtp->vt_par);
+
+    /* Next element in the list, if the list is empty then the timer is
+       stopped.*/
     chSysLockFromISR();
-  }
-  if (&ch.vtlist == (virtual_timers_list_t *)ch.vtlist.vt_next) {
-    /* The list is empty, no tick event needed so the alarm timer
-       is stopped.*/
-    port_timer_stop_alarm();
-  }
-  else {
-    /* Updating the alarm to the next deadline, deadline that must not be
-       closer in time than the minimum time delta.*/
-    if (vtp->vt_delta >= (systime_t)CH_CFG_ST_TIMEDELTA) {
-      port_timer_set_alarm(now + vtp->vt_delta);
-    }
-    else {
-      port_timer_set_alarm(now + (systime_t)CH_CFG_ST_TIMEDELTA);
+    vtp = ch.vtlist.vt_next;
+    if (&ch.vtlist == (virtual_timers_list_t *)vtp) {
+      port_timer_stop_alarm();
+      return;
     }
   }
+  /* Updating the alarm to the next deadline, deadline that must not be
+     closer in time than the minimum time delta.*/
+  delta = (vtp->vt_delta >= (systime_t)CH_CFG_ST_TIMEDELTA) ?
+           vtp->vt_delta : (systime_t)CH_CFG_ST_TIMEDELTA;
+  port_timer_set_alarm(now + delta);
+
+  chDbgAssert((chVTGetSystemTimeX() - ch.vtlist.vt_lasttime) < delta,
+              "exceeding delta");
 #endif /* CH_CFG_ST_TIMEDELTA > 0 */
 }
 
diff --git a/testhal/STM32/STM32F4xx/IRQ_STORM/main.c b/testhal/STM32/STM32F4xx/IRQ_STORM/main.c
index 581a1142a..0b5ae9c00 100644
--- a/testhal/STM32/STM32F4xx/IRQ_STORM/main.c
+++ b/testhal/STM32/STM32F4xx/IRQ_STORM/main.c
@@ -302,6 +302,7 @@ int main(void) {
         print("#");
         if (threshold == 0)
           threshold = interval;
+        break;
       }
     }
     /* Gives the worker threads a chance to empty the mailboxes before next
-- 
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