[Qemu-devel] [PATCH 1/2] arm_mptimer: Fix timer shutdown and mode change

[Dmitry Osipenko <digetx@gmail.com>]

Timer, running in periodic mode, can't be stopped or coming one-shot
tick won't be canceled because timer control code just doesn't handle
timer disabling. Fix it by deleting the timer if enable bit isn't set.

Timer won't start periodic ticking if ONE-SHOT -> PERIODIC mode change
happened after one-shot tick was completed. Fix it by starting ticking
only if the timer isn't ticking right now.

To avoid code churning, these two fixes are squashed in one commit.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---

Commits are squashed as per Peter Crosthwaite suggestion.

 hw/timer/arm_mptimer.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/hw/timer/arm_mptimer.c b/hw/timer/arm_mptimer.c
index 8b93b3c..0e132b1 100644
--- a/hw/timer/arm_mptimer.c
+++ b/hw/timer/arm_mptimer.c
@@ -122,11 +122,18 @@ static void timerblock_write(void *opaque, hwaddr addr,
     case 8: /* Control.  */
         old = tb->control;
         tb->control = value;
-        if (((old & 1) == 0) && (value & 1)) {
-            if (tb->count == 0 && (tb->control & 2)) {
+        if (value & 1) {
+            if ((old & 1) && (tb->count != 0)) {
+                /* Do nothing if timer is ticking right now.  */
+                break;
+            }
+            if (tb->control & 2) {
                 tb->count = tb->load;
             }
             timerblock_reload(tb, 1);
+        } else if (old & 1) {
+            /* Shutdown the timer.  */
+            timer_del(tb->timer);
         }
         break;
     case 12: /* Interrupt status.  */
-- 
2.4.4